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The Pharmacokinetic/Pharmacodynamic (PK/PD) relationship of antimicrobial drugs (AMD) for surgical prophylaxis has been poorly studied, hampering evidence-based decision making around AMD dosing and timing. Our objective is to use PK/PD principles to inform (1) the timing of administration and (2) the interval for re-administration of AMD used peri-operatively in dogs. Raw plasma concentrations of cefazolin, cefuroxime, cefalexin, amoxicillin and ampicillin were retrieved from original intravenous studies performed in dogs. E. coli and methicillin-susceptible staphylococci were identified as possible intraoperative contaminants and their epidemiological cut-offs (ECOFF) were retrieved from the EUCAST database. Individual PK data were refitted with non-linear mixed effect models (Phoenix®). We performed Monte Carlo simulation to compute i) the 95 th percentile of time of peak concentration in the peripheral compartment (informing timing between administration and first incision) and ii) the duration for which at least 90% of dogs maintain a free plasma concentration above ECOFF (informing timing of re-administration: 1.5-4 h). Cefazolin (22-25 mg/kg), cefuroxime (20 mg/kg), cefalexin (15 mg/kg) and amoxicillin (16.7 mg/kg) reached peak peripheral concentrations within 30 min, but ampicillin (20 mg/kg) required 82 min, respectively. For methicillin-susceptible staphylococci, cefazolin and cefuroxime require re-administration every 2 h, whereas cefalexin and both amoxicillin and ampicillin can be readministered every 3 and 4 h, respectively. For E. coli, only cefazolin provided adequate perioperative coverage with 2-hourly administration, where cefuroxime and cefalexin failed uniformly. Alternatively, ampicillin and amoxicillin (critically ill dogs) may cover E. coli contaminations, but only if readministered every 1.5 h. These PK-derived conclusions provide a rationale for perioperative AMD administration timing., Competing Interests: Declaration of Competing Interest The authors of the manuscripts are members of ENOVAT working groups (WG1: FA, WG2: LP, WG3: LP, PC and WG4: LP, TMS, FA) and the veterinary subcommittee of EUCAST named VetCAST (LP, PC, PLT). None of the authors has any financial or personal relationships that could inappropriately influence or bias the content of the paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Objective: To evaluate the knowledge, attitudes, and practices toward antibiotic use among board-certified veterinary dentists., Sample: 104 veterinarians board certified by the American Veterinary Dental College., Methods: A 30-question survey was generated from an online platform and sent via email listserv to board-certified veterinary dentists. Responses were examined to identify patterns or correlations among the variables of interest., Results: There were 104 board-certified veterinary dentists who responded. The majority reported using prophylactic intraoperative antibiotics sparingly for dental procedures and predominately for patients with historic endocarditis or on immunosuppressive doses of steroids. For healthy patients, they reported that antibiotics are often prescribed during jaw fracture repair, maxillectomy/mandibulectomy, and treatment of stage 4 periodontal disease or periapical lucencies. Knowledge of antibiotic resistance and evidence-based antibiotic use were not significantly different between different practice sectors (academia vs private practice) or dependent on the duration of board certification. Dentists who did not believe antibiotics used postoperatively reduce local postoperative infection rates were less likely to prescribe injectable intraoperative antibiotics for the prevention of postoperative infection. No other variables were associated with the likelihood of prescribing intraoperative antibiotics. More than 95% of veterinary dentists surveyed agreed that specific antibiotic use guidelines for veterinary dentistry would help reduce inappropriate use of antibiotics., Clinical Relevance: There are differences among veterinary dentists regarding which procedures and patient-specific comorbidities they believe necessitate the use of prophylactic antibiotics. The development of a consensus statement and prospective studies of current antibiotic use are important next steps to improving antibiotic stewardship in veterinary dentistry.

Objectives: To evaluate the effectiveness and complication rate of a 1.5- and 2.0-mm titanium locking plate for the treatment of radial and ulnar fractures in small dog breeds and cats without peri-operative antibiotic prophylaxis in a prospective case series., Materials and Methods: Medical records and radiographs of closed radial and ulnar fractures treated using internal fixation with a 1.5- or 2.0-mm titanium locking plate without antibiotic prophylaxis were collected prospectively. Patients were clinically followed up until radiographical fracture healing was complete., Results: Thirty-two fractures in small breed dogs and cats with an average bodyweight of 3.9 kg met the inclusion criteria. The follow-up time radiographically and clinically was 4-35 weeks. All fractures showed radiographical fracture union, and all patients had a good clinical outcome. The superficial infection rate in this case series was 0%; the deep infection rate involving the implant/bone was 3.1%., Clinical Significance: The novel 1.5- and 2.0-mm titanium locking plate system was successfully used to treat simple closed radial and ulnar fractures in small breed dogs and cats without peri-operative antibiotic prophylaxis, resulting in good clinical outcome and a low infection rate., (© 2021 British Small Animal Veterinary Association.)

Background: Mastectomy is the most common procedure for treatment of mammary tumours. Dogs undergoing mastectomy have a risk of developing surgical site infections (SSI) and other postoperative complications. However, potential risk factors associated with such complications have been sparsely investigated. Thus, the objective of this retrospective study was to determine the incidence of, and identify risk factors for, SSI and non-SSI postoperative complications after mastectomy performed without perioperative antimicrobial prophylaxis in privately owned otherwise clinically healthy dogs., Results: Medical records were reviewed retrospectively for 135 client-owned female dogs, 10-35 kg in weight and three to 10 years of age, which had undergone mastectomy due to mammary tumours at three referral animal hospitals in Sweden over a 3-year period. Twelve (8.9%) dogs developed SSI, and 21 dogs (17.1%) dogs suffered a non-SSI postoperative complication. The incidence of SSI and all complications (SSI and non-SSI) were higher in dogs that had two to three (SSI: P = 0.036 and all complications: P = 0.0039) and four to five (SSI and all complications: P = 0.038) mammary glands excised, compared to dogs that had one mammary gland excised. The incidence of SSI was 1.7% (n = 1/60) in dogs that had one gland removed. The incidence of non-SSI postoperative complications was higher in dogs with a higher body weight (P = 0.02)., Conclusions: The incidence of SSI was lower than or similar to previously reported incidences of SSI in dog populations that have undergone tumour excisional surgery, despite the fact that dogs in the present study had not received perioperative antibiotics. Dogs that had two or more glands excised had an increased risk of developing SSI and non-SSI complications compared to dogs that had one gland excised. Furthermore, higher BW was associated with an increased risk of non-SSI complications. Results from the study indicate that routine use of perioperative antibiotics in tumour excisional surgery can be questioned, at least in single gland mastectomy in otherwise clinically healthy dogs., (© 2021. The Author(s).)

This objective of this study was to evaluate the use of tulathromycin on the timing of appearance and number of four indicator organisms representing the gastrointestinal microbial community, the incidence of diarrhea and a measure of the systemic inflammatory profile in Holstein heifers. Twenty-six Holstein heifer calves were distributed between receiving (ATB+) or not receiving (ATB-) tulathromycin at a dose of 2.5 mg/kg by 12 h of age. Samples from the calves were collected at six times during the neonatal period. Stool samples were used to determine the dry matter content and quantitative analysis of specific indicator bacterial populations. Samples of whole blood and serum were collected to determine the total number of neutrophils, the number of CD62L+ neutrophils, quantity of haptoglobin, and to allow for ex vivo measurement of reactive oxygen species. A higher frequency of diarrhea was detected in the ATB+ calves (84.6%) than ATB- (53.8%) on days 13-15 (P = 0.084). ATB- calves had a greater number of Bifidobacterium in stool on day 3-5 (P = 0.002), and on days 7-9 (P = 0.018). The ATB+ calves tended to have a higher number of Escherichia coli in stool on days 20-23 and days 27-30 (P = 0.052 and P = 0.072). Both the total number of neutrophils (P = 0.013) and the capacity for ROS production was higher in ATB- (P = 0.038) than ATB+ calves at all points tested. ATB+ calves had higher levels of haptoglobin (P = 0.032) on days 13-15. Administration of tulathromycin appeared to negatively impact the establishment of a normal microbiome and to modulate the development of innate immune function., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Background: Surgical site infections (SSI) are associated with increased morbidity and mortality. To lower the incidence of SSI, antimicrobial prophylaxis is given 30-60 min before certain types of surgeries in both human and veterinary patients. However, due to the increasing concern of antimicrobial resistance, the benefit of antimicrobial prophylaxis in clean orthopaedic and neurosurgeries warrants investigation. The aims of this retrospective cross-sectional study were to review the rate of SSI and evaluate the compliance with antimicrobial guidelines in dogs at a veterinary teaching hospital in 2012-2016. In addition, possible risk factors for SSI were assessed., Results: Nearly all dogs (377/406; 92.9%) received antimicrobial prophylaxis. Twenty-nine dogs (7.1%) did not receive any antimicrobials and only four (1.1%) received postoperative antimicrobials. The compliance with in-house and national protocols was excellent regarding the choice of prophylactic antimicrobial (cefazolin), but there was room for improvement in the timing of prophylaxis administration. Follow-up data was available for 89.4% (363/406) of the dogs. Mean follow-up time was 464 days (range: 3-2600 days). The overall SSI rate was 6.3%: in orthopaedic surgeries it was 6.7%, and in neurosurgeries it was 4.2%. The lowest SSI rates (0%) were seen in extracapsular repair of cranial cruciate ligament rupture, ulnar ostectomy, femoral head and neck excision, arthrotomy and coxofemoral luxation repair. The highest SSI rate (25.0%) was seen in arthrodesis. Omission of antimicrobials did not increase the risk for SSI (P = 0.56; OR 1.7; CI 95% 0.4-5.0). Several risk factors for SSI were identified, including methicillin-resistant Staphylococcus pseudintermedius carriage (P = 0.02; OR 9.0; CI 95% 1.4-57.9) and higher body temperature (P = 0.03; OR 1.69; CI 95% 1.0-2.7; mean difference + 0.4 °C compared to dogs without SSI)., Conclusions: Antimicrobial prophylaxis without postoperative antimicrobials is sufficient to maintain the overall rate of SSI at a level similar to published data in canine clean orthopedic and neurosurgeries.

Absolute neutrophil count (ANC) cut-offs for antimicrobial prophylaxis in veterinary cancer chemotherapy patients are empirical and vary between institutions. Evidence based cut-offs are vital for antimicrobial stewardship, particularly as global antimicrobial resistance rises. The primary objectives of this study were to evaluate the tolerability of a <0.75 × 10 9 /l ANC cut-off for antimicrobial prophylaxis in dogs after receiving chemotherapy and its impact on antimicrobial prescription. Predicted nadir ANCs (pnANCs) were stratified into six groups (<0.75 × 10 9 /l [receiving antimicrobial prophylaxis], 0.75-0.99 × 10 9 /l, 1-1.49 × 10 9 /l, 1.5-1.99 × 10 9 /l, 2.0-3.59 × 10 9 /l and 3.6-12 × 10 9 /l [reference interval]). The incidences of post-nadir febrile neutropenia (FN) and non-haematological toxicity (NHT) were compared between groups. Five hundred and eighty-six pnANCs were recorded for 181 dogs. There were four episodes of post-nadir FN and 90 episodes of post-nadir NHT. There was no significant difference in incidence of post-nadir FN (P = .063) or post-nadir NHT (P = .084) between pnANC groups. Antimicrobial prophylaxis was prescribed following 8.8% of the chemotherapy administrations; had cut-off values of <1.0 × 10 9 /l or <1.5 × 10 9 /l been used it would have been prescribed in 15.3% and 25.8% of cases respectively. An ANC cut-off of <0.75 × 10 9 /l for antimicrobial prophylaxis appears to be well tolerated and minimizes the prescription of antimicrobials., (© 2019 John Wiley & Sons Ltd.)

Histomoniasis is currently a re-emerging disease of major significance for many commercial turkey and broiler breeder production companies because of the unavailability of drugs or vaccines. The protozoa Histomonas meleagridis (HM) requires the presence of enteric microflora to promote the disease. The objectives of this research note were to evaluate the effect of dietary administration of sodium chlorate (SC) and sodium nitrate (SN) in vitro and in vivo for HM prophylaxis in poults. A total of 128 day-of-hatch female poults obtained from a commercial hatchery were wing-tagged and randomly assigned into 1 of 4 experimental groups: negative control (NC), positive control, dietary inclusion of SC (3,200 ppm) and SN (500 ppm). Poults from groups SC and SN started on their respective diets on day 12. All groups, except the NC, were challenged with 2 × 10 5 HM on day 19. Controls were fed a basal diet, identical to the treatment diets but not supplemented with SC or SN. Body weight gain (BWG) was determined weekly, starting on day 1 until day 28, and postchallenge morbidity and mortality were recorded. On day 28 of age, all surviving poults were lesion scored for hepatic and cecal lesions. Ceca and distal ileum were collected on day 28 for bacterial recovery on selective media for total aerobic, lactic acid bacteria, or gram-negative bacteria. The addition of SC and SN in the in vitro growth of HM greatly reduced the growth of the protozoa after 20 h of incubation when compared with the control nontreated group (P < 0.05). However, dietary supplementation of SC and SN had no effect against HM in vivo, as was demonstrated by BWG, the severity of lesions in the liver and ceca or bacterial recovery of treated poults when compared with the positive control group., (Copyright © 2020 The Authors. Published by Elsevier Inc. All rights reserved.)

Bio-logging devices can provide unique insights on the life of freely moving animals. However, implanting these devices often requires invasive surgery that causes stress and physiological side-effects. While certain medications in connection to surgeries have therapeutic capacity, others may have aversive effects. Here, we hypothesized that the commonly prescribed prophylactic treatment with enrofloxacin would increase the physiological recovery rate and reduce the presence of systemic inflammation following the intraperitoneal implantation of a heart rate bio-logger in rainbow trout (Oncorhynchus mykiss). To assess post-surgical recovery, heart rate was recorded for 21 days in trout with or without enrofloxacin treatment. Contrary to our hypothesis, treated trout exhibited a prolonged recovery time and elevated resting heart rates during the first week of post-surgical recovery compared to untreated trout. In addition, an upregulated mRNA expression of TNFα in treated trout indicate a possible inflammatory response 21 days post-surgery. Interestingly, the experience level of the surgeon was observed to have a long-lasting impact on heart rate. In conclusion, our study showed no favorable effects of enrofloxacin treatment. Our findings highlight the importance of adequate post-surgical recovery times and surgical training with regards to improving the welfare of experimental animals and reliability of research outcomes.

The use of prophylactic antibiotics in veterinary surgery reduces the occurrence of postoperative complications. In order to limit the development of antimicrobial resistance in bacteria and to maximize therapy efficacy, antibiotics should be used prudently and efficiently. A survey was sent to Wallonian rural veterinarians in order to assess the use of antibiotics before, during and after bovine elective caesarean section, the most common surgical procedure in Belgian rural practice. Results were analysed in the light of the current guidelines formulated by the Belgian Centre of Expertise on Antimicrobial Consumption and Resistance in Animals. Among 380 contacted veterinarians, 113 answered the survey. All veterinarians use antibiotics during caesarean section. Veterinarians predominantly use penicillin as the first drug of choice, whereas a minority use drugs considered as second or third choice, such as amoxicillin, oxytetracyclin or lincomycin-spectinomycin. Also, 31/113 veterinarians simultaneously use molecules from different antibiotic classes. The majority (100/113) of veterinarians inject antibiotics during or after surgery, while a minority (13/113) administer antibiotics preoperatively. Most veterinarians (67/113) limit the duration of their antibiotic treatment to 1 day. Considering the administration route, most veterinarians (88/113) systematically use the intraperitoneal injection route, which is not registered. Intramuscular injection and injection between muscle layers during surgery are carried out by 82/113 and 43/113 respondents, respectively. Twenty-two respondents apply intra-uterine antibiotics. Most veterinarians (87/113) combine several administration routes. The dosage of antibiotics varies enormously and excessive injection volumes are common, especially when multiple injection routes are combined. Our results show a striking lack of consistency in the antibiotic therapy during elective CS by rural veterinarians. Whereas the drug of choice and the treatment duration were largely in line with the current guidelines, this is certainly not the case for the dosage and the administration route. The intraperitoneal injection of antibiotics cannot be justified. Incorrect dosage of antibiotics should be avoided at all cost. The use of second and third line molecules and the simultaneous use of different antibiotic classes should be discouraged. A major challenge lies in the education of veterinary students and the sensitization of practitioners to avoid or unlearn unnecessary habits concerning antibiotic use. Finally, more clinical trials are needed in order to refine the current guidelines for antibiotic use and to determine the optimal drug of choice, treatment moment and application route in elective caesarean section in cattle., (Copyright © 2019 Elsevier B.V. All rights reserved.)

The Australian Veterinary Prescribing Guidelines for antimicrobial prophylaxis for surgery on dogs and cats are evidence-based guidelines for veterinary practitioners. Validation of these guidelines is necessary to ensure quality and implementability. Two validated tools, used for medical guideline appraisal, were chosen to assess the guidelines. The terminology from the GuideLine Implementability Appraisal (GLIA) and the Appraisal of Guidelines for Research and Evaluation version 2 (AGREE II) were adapted for use by veterinarians. A two-phase evaluation approach was conducted. In the first phase of the evaluation, the GLIA tool was used by two specialist veterinary surgeons in clinical practice. The results of this phase were then used to modify the guidelines. In the second phase, the AGREE II tool was used by 6 general practitioners and 6 specialists to appraise the guidelines. In phase 1, the specialist surgeons either agreed or strongly agreed that the guidelines were executable, decidable, valid and novel, and that the guidelines would fit within the process of care. The surgeons were neutral on flexibility and measurability. Additional clarity around one common surgical procedure was added to the guidelines, after which the surgeons agreed that the guidelines were sufficiently flexible. In phase 2, 12 veterinarians completed the assessment using the AGREE II tool. In all sections the scaled domain score was greater than 70%. The overall quality of the guidelines was given a global scaled score of 76%. This assessment has demonstrated that the guidelines for antimicrobial prophylaxis for companion animal surgery are valid and appear implementable., (© 2019 Australian Veterinary Association.)

Objectives: In humans with herpetic disease, early or pre-emptive famciclovir therapy reduces disease duration and severity. This prospective, masked, placebo-controlled study tested therapeutic and prophylactic effects of two famciclovir doses given to cats for 7 days following shelter entry., Methods: Cats were assigned to prophylactic or therapeutic study arms based on clinical evidence of herpetic disease at study entry. Cats in the therapeutic arm received no treatment (n = 19), placebo (lactose; n = 18) or famciclovir at ~30 (n = 21) or ~90 mg/kg (n = 20) PO q12h for 7 days. Cats in the prophylactic arm received no treatment (n = 25) or famciclovir at ~30 (n = 28) or ~90 mg/kg (n = 27) PO q12h for 7 days. Disease scores, body weight, conjunctival feline herpesvirus 1 (FHV-1) shedding, and adoption rates were recorded on days 1 (admission), 8 (end of therapy) and 15 (1 week after cessation of therapy)., Results: No significant differences in clinical scores were observed among groups in the prophylactic or therapeutic arms at any of the three time points. However, within the therapeutic arm, viral shedding on day 8 was significantly higher in cats receiving no treatment than in those receiving ~30 or ~90 mg/kg famciclovir, and this effect persisted 1 week after famciclovir was stopped (day 15) only in cats receiving ~30 mg/kg, although this approached significance in cats receiving ~90 mg/kg. No significant differences in adoption rates were detected among groups in either arm throughout the study., Conclusions and Relevance: Although we did not demonstrate a statistically or clinically significant effect of famciclovir administration upon clinical signs of infectious upper respiratory disease or adoption, when it was administered at ~30 or ~90 mg/kg q12h for 1 week famciclovir reduced conjunctival FHV-1 shedding. This suggests a potential role in interrupting the infectious cycle within a shelter population; however, cost in time and resources, and stress and pathogen transmission induced by oral administration should be considered.

The increase in antimicrobial-resistant (AMR) bacteria caused by antimicrobial usage is a public health problem. We investigated the proportion of cephalexin (LEX)-resistant bacteria in fresh feces obtained from antimicrobial-free broilers in three flocks at ＜15, 15-40, and＞ 40 days old. DHL agar plates containing 25 μg/mL LEX (DHL-L) showed LEX-resistant bacteria in all flocks at ＜15 days old and in one flock at ＞ 40 days old. The bacterial counts on DHL and DHL-L were 10 5 -10 8 colony forming units (CFU)/g feces and ＜10 2 -10 5 CFU/g feces, respectively. We also assessed the proportion of AMR bacteria in feces collected at 5, 12, 19, 26, 33, and 40 days old from two flocks treated with amoxicillin at 5-7 days old and co-trimoxazole at 24-26 days old. The proportion of ampicillin (AMP)-resistant bacteria was elevated at 12 and 26-33 days old on DHL containing 50 μg/mL AMP, while no increase in LEX-resistant bacteria was observed on DHL-L. All isolates tested exhibited AMP resistance at 12 days old, while most exhibited resistance to both AMP and trimethoprim/sulfamethoxazole at 26-33 days old. Our results suggest that antimicrobial administration influenced the selection of AMR bacteria with cross- and coresistance.

Background: Antibiotics (AB) are an important tool to tackle infectious disease in pig farms; however some research indicates that their frequent mis/over-use may contribute to the development of antibiotic resistance and the WHO has declared that this issue should be addressed. Little is known about the long term consequences of withdrawing prophylactic AB from pig feed; hence we aimed to assess its effects on performance and health of pigs from weaning to slaughter. Six batches of 140 pigs each were monitored on a commercial farm through the weaner and finisher stages to slaughter. In-feed antibiotics were not added to the feed for half of the pigs (NOI) and were added in the other half (ABI) within each batch for the whole weaner stage. Individual pigs in both treatments were treated with parenteral administrations if and when detected as ill or lame. Productive performance, parenteral treatments and mortality were recorded on farm and the presence of respiratory disease was recorded at slaughter. Pen was considered the experimental unit., Results: ABI pigs showed higher growth (P = 0.018) and feed intake (P = 0.048) than NOI pigs in the first weaner stage but feed efficiency was not affected (NOI = 1.48 vs. ABI = 1.52). Despite an initial reduction in performance, NOI pigs had similar performance in finisher stage (ADG: NOI = 865.4 vs. ABI = 882.2) and minimal effects on health compared to ABI pigs. No difference between treatments was found at the abattoir for the percentage of pigs affected by pneumonia, pleurisy, pleuropneumonia and abscesses (P > 0.05). Mortality rate was not affected by treatment during the weaner stage (P = 0.806) although it tended to be slightly higher in NOI than ABI pigs during the finisher stage (P = 0.099). Parenteral treatments were more frequent in NOI pigs during the weaner stage (P <  0.001) while no difference was recorded during the finisher stage (P = 0.406)., Conclusions: These data suggest that the removal of prophylactic in-feed antibiotics is possible with only minor reductions in productive performance and health which can be addressed by improved husbandry and use of parenteral antibiotics.

Although aquaculture activity has experienced a great development over the past three decades, infectious diseases have become a limiting factor for further intensification. Because the use of antibiotics has led to the widespread emergence of antibiotic resistance, the search for alternative environmentally friendly approaches is urgently needed. This Opinion paper offers an update on the successes and challenges of biological approaches for bacterial disease prevention and control in aquaculture. Although most of these approaches are still in research and development stages, some of them have shown promising results in field trials. Therefore, a better understanding of the mechanisms of action of these approaches will help to maximise their beneficial properties., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Societal concerns about antibiotic resistance prompted us to evaluate the use of prophylactic and postoperative antibiotic treatments following cesarean section (CS) and exploratory laparotomy (EL) in a surgery theater within the Farm Animal Health clinic. All procedures were performed by supervised veterinary students for training purposes. Cows undergoing CS (n = 100) received either a prophylaxis with a single 5-g injection of ampicillin-sodium i.v. only (CSL), or in combination with postoperative i.m. injections of ampicillin-trihydrate 20% for 3 d (10 mg/kg, twice a day; CSH). Cows undergoing EL (n = 110) received either no antibiotic prophylaxis (ELN) or were given a single 5-g injection of ampicillin-sodium i.v. (ELL). The primary outcome measure was healthy recovery after surgery, which we assessed according to the need to treat surgery-related complications within a 10-d follow-up period based on daily clinical observations. Cows in all groups had a normal temperature and feed intake, and a satisfying clinical appearance at the end of the follow-up period. The clinical need to treat cows with antibiotics to deal with postoperative complications was higher for the CS groups than the EL groups. Within both CS and EL groups, the number of complications for each protocol was the same. However, in terms of the secondary outcomes, we observed that CSL cows required, for example, more treatments for mastitis and other diseases unrelated to the surgery than CSH cows (odds ratio 2.8; confidence interval 1.2-7.2). The percentage of infected sutures was higher for ELN cows compared with ELL cows (odds ratio 2.6; confidence interval 1.5-4.9). We estimated that 29 CSH treatments were needed to prevent 1 CS cow with serious surgery-related complications in the CSL group. Likewise, 53 ELL treatments would prevent 1 EL cow with surgery-related complications in the ELN group. We therefore concluded that it is possible to reduce antibiotic prophylaxis in CS and EL cows. The low number cows of clinically detected complications were effectively treated with a postoperative antibiotic intervention at the moment of detection., (The Authors. Published by FASS Inc. and Elsevier Inc. on behalf of the American Dairy Science Association®. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/3.0/).)

Bacterial infection following cancer chemotherapy-induced neutropenia is a serious cause of morbidity and mortality in human and veterinary patients. Antimicrobial prophylaxis is controversial in the human oncology field, as any decreased incidence in bacterial infections is countered by patient adverse effects and increased antimicrobial resistance. Comprehensive guidelines exist to aid human oncologists in prescribing antimicrobial prophylaxis but similar recommendations are not available in veterinary literature. As the veterinarian's role in antimicrobial stewardship is increasingly emphasized, it is vital that veterinary oncologists implement appropriate antimicrobial use. By considering the available human and veterinary literature we present an overview of current clinical practices and are able to suggest recommendations for prophylactic antimicrobial use in veterinary cancer chemotherapy patients., (© 2018 The Authors. Veterinary and Comparative Oncology published by John Wiley & Sons Ltd.)

Objective:  The aim of this study was to retrospectively review the surgical site infection (SSI) rate in dogs undergoing laminectomies without perioperative antibiotics, and compare those data with the expected infection rate for clean surgical wounds in dogs undergoing similar procedures., Methods:  This was a retrospective single-centre study composed of dogs that underwent hemilaminectomies or laminectomies for thoracolumbar disc herniation or lumbosacral disease during a 2-year period (during 2015 and 2016). All incisional complications within 30 days were recorded and divided into superficial, deep or organ/space infections. Those dogs that received perioperative or postoperative antibiotics due to non-related comorbidities and those with incomplete medical records during the study period were excluded., Results:  Of 221 consecutive hemilaminectomy and laminectomy procedures, 154 were included in this research study. One superficial wound infection was recorded and treated with antimicrobials. Overall, the SSI rate was 0.6%, while the expected SSI rate in clean operative wounds in dogs and cats is 2.0 to 4.8%. The SSI rate in human spinal surgery is 0.7 to 4.3%., Clinical Significance:  Considering the low incidence of SSI in our study group, the routine use of perioperative antibiotic prophylaxis in dogs undergoing laminectomy procedures should be reconsidered to help address the global problem of bacterial resistance., Competing Interests: None., (Schattauer GmbH Stuttgart.)

Objective: Retrospective analysis of postoperative complications in equines after clean, orthopaedic surgical procedures in order to detect differences between animals treated with antibiotics and horses without receiving these drugs., Material and Methods: Details on 652 patients, surgical procedures and surgery-associated complications were compiled from horses being operated between June 2011 and January 2015. Antibiotic-receiving patients (n = 259) were tested for differences in complication rates and characteristics to controls (n = 393)., Results: The total complication rate was 39.1 %. Increased swelling was observed most often (25.6 %), followed by exudation (7.5 %), fever without incisional alterations (2.3 %), suture dehiscence (1.8 %), and seroma (0.8 %). Seven patients (five treated, two controls) developed septic arthritis within a total of 463 arthroscopies (1.5 %). There were no significant differences in the development of postoperative complications, which were seen in 97/259 (37.5 %) antibiotic receiving patients and in 158/393 (40.2 %) controls. The application of perioperative antibiotics was significantly influenced by surgeon (p < 0.0001) and type of surgery (p = 0.0007) and increased with the number of surgical lesions (p = 0.03). In patients undergoing tendovaginoscopy/ bursoscopy, fasciotomy and neurectomy (n = 98), antibiotic prophylaxis was initiated less frequently than in other surgeries, e. g. combinations of surgeries, splint bone extraction, tenotomy, and arthroscopy (n = 554)., Conclusion: Severe complications in equine clean orthopaedic surgery are rare and complication rates in patients either receiving perioperative antibiotics or not were not significantly different., Clinical Relevance: Based on the results the use of antibiotics appears to be non-essential in uncomplicated elective orthopaedic interventions in the horse., Competing Interests: The authors confirm that they do not have any conflict of interest., (Schattauer GmbH.)

Background: Acute radiation-induced dermatitis (ARID) is a common sequela of radiation therapy and carries the risk of secondary bacterial skin infection. No standard of care exists for managing canine ARID and evidence-based guidelines are lacking; however, prophylactic use of antibiotics is common., Hypothesis/objectives: To evaluate the impact of prophylactic cefalexin on the prevalence and severity of bacterial infection in canine ARID., Animals: Seventeen dogs treated with definitive-intent radiotherapy., Methods: All dogs were treated with definitive-intent radiation therapy (48-57.5 gray) targeted to the skin surface. Dogs were randomized to receive either prophylactic cefalexin (22 mg/kg twice daily) beginning halfway through the prescribed radiotherapy course (cohort A) or to serve as controls (cohort B). Aerobic skin cultures and surface cytological evaluation were performed at first onset of moist desquamation and one week following completion of radiation therapy. Skin toxicity grading and owner quality of life (QoL) questionnaires were performed weekly. The rate of infection, multidrug resistance status, toxicity severity and QoL between cohorts were compared., Results: Staphylococcus schleiferi and S. pseudintermedius were the most frequent bacterial agents isolated in both cohorts. There was no significant difference in prevalence of bacterial infection or overall QoL between cohorts at either time point; however, multidrug-resistant infections were significantly increased in cohort A versus cohort B. Clinician- and client-perceived severity of toxicity was significantly greater and median duration of moist desquamation was significantly longer in cohort A than cohort B., Conclusions and Clinical Importance: Prophylactic use of cefalexin for management of canine ARID is not recommended., (© 2017 ESVD and ACVD.)

Antibiotic prophylaxis in dogs undergoing surgical procedures frequently involves the administration of a product without a veterinary licence. Two drugs commonly used for this purpose are the clavulanate amoxicillin Augmentin and the cefuroxime Zinacef. This prospective observational study aims to compare the incidence of adverse events associated with these two antibiotics in a clinical setting. The authors hypothesised that a higher incidence of adverse effects would be observed with Augmentin. Sixty-five dogs were included in the study and adverse events were recorded using a modified scoring system. A significantly higher incidence of adverse events to Augmentin (8/22; 36 per cent) was observed compared with Zinacef (1/43; 2 per cent) (P=0.0003). The majority of these adverse events involved cutaneous signs and/or hypotension. These findings might be taken into consideration when selecting one of these intravenous antibiotics for prophylaxis in anaesthetised dogs undergoing surgery., Competing Interests: Competing interests: None declared., (© British Veterinary Association (unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.)

Background: Prechemotherapy absolute neutrophil count (ANC) cutoffs are arbitrary and vary across institutions and clinicians. Similarly, subjective guidelines are utilized for the administration of prophylactic antibiotics in neutropenic dogs., Objectives: To evaluate the impact of various ANC cutoffs on chemotherapy administration in dogs with lymphoma treated with CHOP chemotherapy and to determine whether an association between prechemotherapy ANC and subsequent toxicity exists. The secondary objective was to evaluate a currently used ANC cutoff to indicate prescription of prophylactic antibiotics., Animals: Dogs diagnosed with lymphoma treated with CHOP chemotherapy (n = 64)., Methods: Six hundred and fifteen ANCs were stratified into 6 classes. The 3 ANC cutoffs 1.5 × 10 3 /μL, 2.0 × 10 3 /μL, and 2.5 × 10 3 /μL were assessed. The presence of an association between prechemotherapy ANC class and toxicity was determined. Afebrile neutropenic dogs with ANC <1.5 × 10 3 /μL but above the criteria for prophylactic antibiotics were evaluated., Results: Chemotherapy was not administered in 7% of visits with an ANC cutoff of 1.5 × 10 3 /μL; chemotherapy would not have been administered in 10% and 16% of visits with an ANC cutoff of 2.0 × 10 3 /μL or 2.5 × 10 3 /μL, respectively. There was no association among the 3 lower prechemotherapy ANC classes and toxicity. All dogs with ANC 0.75-1.5 × 10 3 /μL recovered spontaneously without medical intervention., Conclusion and Clinical Importance: The number of dose delays was minimized with a prechemotherapy ANC cutoff of 1.5 × 10 3 /μL, and the prechemotherapy ANC class 1.5-1.99 × 10 3 /μL was not associated with an increased toxicity. Further investigation of an ANC cutoff near 0.75 × 10 3 /μL in which to prescribe prophylactic antibiotics is indicated., (Copyright © 2017 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals, Inc. on behalf of the American College of Veterinary Internal Medicine.)

When traumatic wounds are quickly and accurately treated, morbidity and costs can be significantly decreased. Several factors, such as time delay between injury and treatment, the degree of contamination, extension and depth of the wound, and the mechanism of injury, influence the treatment and prognosis and stress the importance of a patient-specific approach. Although all traumatic wounds are contaminated, antibiotic therapy is seldom required if correct wound management is installed., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Antimicrobials are widely used in veterinary practices, but there has been no investigation of antimicrobial classes used or the appropriateness of their use in bovine practice. This study investigated antimicrobial use for surgical prophylaxis in bovine practice in Australia. A cross-sectional study of veterinarian antimicrobial usage patterns was conducted using an online questionnaire. Information solicited included respondent's details, the frequency with which antimicrobials were used for specific surgical conditions (including the dose, timing and duration of therapy) and details of practice antimicrobial use policies and sources of information about antimicrobials. In total, 212 members of the Australian veterinary profession working in bovine practice completed the survey. Antimicrobials were always or frequently used by more than 75 per cent of respondents in all scenarios. Generally, antimicrobial drug choice was appropriate for the reported surgical conditions. Procaine penicillin and oxytetracycline accounted for 93 per cent of use. However, there was a wide range of doses used, with underdosing and inappropriate timing of administration being common reasons for inappropriate prophylactic treatment. There was very low use of critically important antimicrobials (3.3 per cent of antimicrobials reported). Antimicrobial use guidelines need to be developed and promoted to improve the responsible use of antimicrobials in bovine practice., Competing Interests: Competing interests: None declared., (© British Veterinary Association (unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.)

OBJECTIVE To evaluate pharmacokinetics of cefazolin after IV injection of cefazolin (22 mg/kg) and after simultaneous IV and IM injections of cefazolin (total dose, 44 mg/kg) to dogs. ANIMALS 12 adult Beagles. PROCEDURES Dogs (6/group) were assigned to receive a single injection of cefazolin (IV group; 22 mg/kg, IV) or simultaneous injections (IV + IM group; 22 mg/kg, IV, and 22 mg/kg, IM). Interstitial fluid was collected over a 5-hour period by use of ultrafiltration probes for pharmacokinetic analysis. RESULTS Mean cefazolin concentration in the interstitial fluid at 1, 1.5, 2, 3, 4, and 5 hours after injection was 39.6, 29.1, 21.2, 10.3, 6.4, and 2.7 μg/mL, respectively, for the IV group and 38.3, 53.3, 46.4, 31.7, 19.1, and 8.9 μg/mL, respectively, for the IV + IM group. Mean area under the concentration-time curve extrapolated to infinity, maximum concentration, half-life, and time to maximum concentration was 74.99 and 154.16 h·μg/mL, 37.3 and 51.5 μg/mL, 0.96 and 1.11 hours, and 1.28 and 1.65 hours, respectively, for the IV and IV + IM groups. CONCLUSIONS AND CLINICAL RELEVANCE Cefazolin concentrations in interstitial fluid of dogs were maintained at > 4 μg/mL for 4 hours after a single IV injection and for 5 hours after simultaneous IV and IM injections. Therefore, simultaneous IV and IM administration of cefazolin 30 to 60 minutes before surgery should provide interstitial fluid concentrations effective against the most common commensal organisms (Staphylococcus spp and Streptococcus spp) on the skin of dogs for surgical procedures lasting ≤ 4 hours.

Antimicrobials are widely used in veterinary practices, but there has been no investigation into the classes of antimicrobials used or the appropriateness of their use in surgical prophylaxis. Antimicrobial usage guidelines were published by the Australian Infectious Disease Advisory Panel (AIDAP) in 2013, but there has been no investigation of compliance with them. This study aimed to investigate antimicrobial use for surgical prophylaxis in companion animal practice and assess compliance with AIDAP guidelines for selected conditions by conducting a cross-sectional study of antimicrobial usage patterns of Australian veterinarians using an online questionnaire. Information solicited included: details of the respondent, the frequency with which antimicrobials were used for specific surgical conditions (including dose and duration) and practice antimicrobial use policies and sources of information about antimicrobial drugs and their uses. A total of 886 members of the Australian veterinary profession completed the survey. Few (22%) reported that their practice that had an antimicrobial use policy. Generally, the choice of antimicrobial drug was appropriate for the given surgical conditions. There was poor compliance with AIDAP guidelines for non-use of antimicrobials for routine neutering. Veterinarians caring solely for companion animals had higher odds of optimal compliance with guidelines than veterinarians in mixed species practices (OR 1.4, 95%CI 1.1-1.9). Recent graduates (>2011) had lower odds of compliance than older graduates (OR 0.8, 95%CI 0.6-0.9). The findings suggest that antimicrobial use guidelines need to be expanded and promoted to improve the responsible use of antimicrobials in small animal practice in Australia., (Copyright © 2017 Elsevier B.V. All rights reserved.)

This study used probabilistic elicitation and a Bayesian framework to quantitatively explore how logically practitioners' update their clinical beliefs after exposure to new data. The clinical context was the efficacy of antibiotics versus teat sealants for preventing mammary infections during the dry period. While most practitioners updated their clinical expectations logically, the majority failed to draw sufficient strength from the new data so that their clinical confidence afterwards was lower than merited. This study provides quantitative insight into how practitioners' update their beliefs. We discuss some of the psychological issues that may be faced by practitioners when interpreting new data. The results have important implications for evidence-based practice and clinical research in terms of the impact that new data may bring to the clinical community., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Undifferentiated fever, or bovine respiratory disease complex (BRDc), is a challenging multi-factorial health issue caused by viral/bacterial pathogens and stressors linked to the transport and mixing of cattle, negatively impacting the cattle feedlot industry. Common practice during processing at feedlots is administration of antibiotic metaphylaxis to reduce the incidence of BRDc. Nitric oxide (NO) is a naturally occurring nano-molecule with a wide range of physiological attributes. This study evaluated the metaphylactic use of intranasal NO releasing spray (NORS) to control BRDc incidence in calves at low-moderate risk of developing BRDc, arriving at a commercial feedlot as compared to conventional antibiotic metaphylaxis. One thousand and eighty crossbred, multiple-sourced, commingled, commercial, weaned beef calves were screened, enrolled, randomized and treated upon arrival. Animals appearing sick were pulled (from their pen) by blinded pen keepers then assessed for BRDc symptoms; blood samples were taken for haptoglobin quantification and the animals were rescued with an antibiotic. After 35 days both groups showed no significant difference in BRDc incidence (5.2% of animals from NORS group and 3.2% from antibiotic group). Average daily weight gain of animals at day 150 for the NORS cohort was 1.17kg compared to 1.18kg for the antibiotic group (p>0.05). There was no significant difference in mortality in the first 35 days (p=0.7552), however, general mortality over 150 days trended higher in the antibiotic cohort. NORS treatment was shown to be safe, causing neither distress nor adverse effects on the animals. This large randomized controlled study in low-moderate BRDc incidence risk calves demonstrates that NORS treatment, as compared to conventional metaphylactic antibiotics, is non-inferior based on BRDc incidence and other metrics like weight and mortality. These data justify further studies in higher BRDc incidence risk populations to evaluate NORS as an alternative strategy to reduce sub-therapeutic metaphylaxis antibiotic use in beef cattle production., (Copyright © 2015 Elsevier B.V. All rights reserved.)

Following introduction of the antimicrobial restrictive "Yellow Card Scheme" in summer 2010, a rapid decrease in the Danish national pig antimicrobial consumption was observed. The aims of this study were to (i) investigate which measures had been implemented to reduce the antimicrobial consumption according to farmers and veterinarians and (ii) where possible, investigate if said measures were reflected in the herds' antimicrobial purchase data. Based on national register data from VetStat and the Central Husbandry Register, the study population was selected among Danish pig herds which had decreased their annual antimicrobial consumption with ≥10% following the introduction of the Yellow Card Scheme comparing June 1, 2009-May 31, 2010 to June 1, 2010-May 31, 2011. Subsequently, questionnaire surveys of both farmers and veterinarians were carried out, resulting in responses from 179 farmers accounting for 202 herds (response ratio: 83%) and 58 veterinarians accounting for 140 herds. Prior to the introduction of the Yellow Card Scheme, 24% of the participating herds had an antimicrobial consumption for one or more age groups which exceeded the Yellow Card Scheme threshold values on antimicrobial consumption, while 50% of the herds had an antimicrobial consumption below the national average. The measures most frequently stated as having contributed to the antimicrobial reduction were increased use of vaccines (52% of farmers; 35% of the veterinarians), less use of group medication (44% of the farmers; 58% of the veterinarians) and staff education (22% of the farmers; 26% of the veterinarians). Reduced usage of antimicrobials for oral use accounted for 89% of the total reduction in antimicrobial use. Among the farmers, 13% also stated that change in choice of product had contributed to reducing their antimicrobial consumption. However, when analyzing purchase data, no general trend was seen towards a larger purchase of products with a higher registered dosage per kg animal compared to similar products. The findings of this study indicate that implementation of antimicrobial restrictive legislation at herd-level may lead to a variety of antimicrobial reducing initiatives in both herds with a high- and herds with a low previous level of antimicrobial consumption., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Antimicrobial usage (AMU) has been described to be high in pig production. Although farmers are aware of the high usage, little is known about intervention to improve the situation. This study evaluated the extent to which AMU could be reduced in pig production by the optimization of herd management, biosecurity status, vaccination strategy, anthelmintic therapy and advice on prudent AMU. Furthermore, the effects of these interventions on the herd production results were explored. This intervention study was conducted on 61 Flemish pig herds and included three visits per herd. During the initial visit, information was gathered on herd management, biosecurity status (quantified by means of the Biocheck.UGent ™ risk-based scoring system), vaccination strategy, anthelmintic therapy and AMU. This info was then translated into a herd-specific action plan which was discussed with the farmer and herd veterinarian/other advisors during the second visit. In the final herd visit (±8 months later), comparable data were obtained to evaluate the progress. Overall, a significant improvement of 2.4 points external and 7 points internal biosecurity on the herds was obtained, combined with additional vaccination, anthelmintic therapy and prudent AMU. This was accompanied by a significant reduction in the AMU with a decrease of 52% for the pigs from birth till slaughter and 32% for breeding animals, based on treatment incidences (TIs) and included an important reduction in the use of critically important antimicrobials. More importantly, the increased biosecurity levels and decreased AMU were combined with significantly improved technical results such as the number of weaned piglets per sow per year (+1.1), daily weight gain (+5.9 g/day) and mortality in the finisher period (-0.6%). Guided interventions as a team effort of farmer and herd veterinarian/other advisors have shown to be a promising method in the reduction of AMU in pig production., (© 2016 Blackwell Verlag GmbH.)

The aim of this study was to evaluate the efficacy of two metaphylactic approaches (long acting antibiotic injected once at 10 days of life or twice at 10 and 35 days of life) on the prevention of bovine respiratory disease (BRD), otitis and mortality in high-risk group-housed pre-weaned Holstein heifer calves. The antibiotic of choice for the metaphylactic approach was a long acting macrolide (tildipirosin) administered subcutaneously at the base of the neck at a dose of 1 mL per 45 kg body weight. A clinical trial was carried out on one dairy farm with random allocation of newborn calves to one of three treatments: (1) control (CTR); (2) one injection at 10 days of life (M1); and (3) two injections at 10 and 35 days of life (M2). Study heifers (n = 795) were reared in group pens of 25 calves per pen and fed unrestricted acidified non-saleable milk from day 1 to day 65 of life. Cox proportional hazard and general linear mixed models were used to evaluate the effect of treatment on mortality, BRD and otitis, and average daily weight gain. The birth weights, proportions of calves with inadequate transfer of passive immunity, proportions of calves born from primiparous dams and proportions of calves born from assisted parturitions were not different among CTR, M1 and M2 treatments. A significantly lower hazard of being affected with BRD and/or otitis (but not for BRD or otitis alone) was observed for M1 (hazard ratio, HR = 0.70, P = 0.009) and M2 (HR = 0.72, P = 0.01) when compared to the CTR group. Metaphylactic treatments had no effect on mortality, otitis and average daily weight gain during the pre-weaning period., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Bovine respiratory disease (BRD) control poses significant challenges to the cattle industry worldwide. The sometimes complex interactions of factors associated with the animal, the pathogen and the environment complicate the implementation of effective control measures. Blanket vaccination or mass medication provides inconsistent control and the effective tackling of BRD will require innovative, evidence-based and targeted interventions which, if employed sensibly, offer useful alternatives for addressing this disease. This review appraises the role of the specific interventions employed in BRD control to assess how our understanding of their role and efficacy has evolved in recent years., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Due to increasing public health concerns that food animals could be reservoirs for antibiotic resistant organisms, calls for reduced current antibiotic use on farms are growing. Nevertheless, it is challenging for farmers to perform this reduction without negatively affecting technical and economic performance. As an alternative, improved management practices based on biosecurity and vaccinations have been proven useful to reduce antimicrobial use without lowering productivity, but issues with insufficient experimental design possibilities have hindered economic analysis. In the present study a quasi-experimental approach was used for assessing the economic impact of reduction of antimicrobial use coupled with improved management strategies, particularly biosecurity strategies. The research was performed on farrow-to-finish pig farms in Flanders (northern region of Belgium). First, to account for technological progress and to avoid selection bias, propensity score analysis was used to compare data on technical parameters. The treatment group (n=48) participated in an intervention study whose aim was to improve management practices to reduce the need for use of antimicrobials. Before and after the change in management, data were collected on the technical parameters, biosecurity status, antimicrobial use, and vaccinations. Treated farms were matched without replacement with control farms (n=69), obtained from the Farm Accountancy Data Network, to estimate the difference in differences (DID) of the technical parameters. Second, the technical parameters' DID, together with the estimated costs of the management intervention and the price volatility of the feed, meat of the finisher pigs, and piglets served as a basis for modelling the profit of 11 virtual farrow-to-finish pig farms representative of the Flemish sector. Costs incurred by new biosecurity measures (median +€3.96/sow/year), and new vaccinations (median €0.00/sow/year) did not exceed the cost reduction achieved by lowering the use of antimicrobials (median -€7.68/sow/year). No negative effect on technical parameters was observed and mortality of the finishers was significantly reduced by -1.1%. Even after a substantial reduction of the antimicrobial treatments, the difference of the enterprise profit increased by +€2.67/finisher pig/year after implementing the interventions. This result proved to be robust after stochastic modelling of input and output price volatility. The results of this study can be used by veterinarians and other stakeholders to incentivise managers of farrow-to-finish operations to use biosecurity practices as a cost-effective way to reduce antimicrobial use., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Surgical site infections (SSI) are an uncommon, but significant, consequence of surgical interventions. There are very few studies investigating SSI risk in veterinary medicine, and even fewer in cattle, despite the fact that major surgeries are commonly conducted on livestock. Furthermore, the suboptimal conditions under which such surgeries are frequently performed on livestock could be considered an important risk factor for the development of SSIs. With increasing public concern over the contribution of veterinary-prescribed antimicrobials to the emergence of antimicrobial-resistant bacteria in people, there is widespread scrutiny and criticism of antimicrobial use in livestock production medicine systems. While the causal link between antimicrobial resistance in livestock and people is heavily debated, it is clear that the prevalence of antimicrobial resistance, in any population, is closely correlated with the antimicrobial 'consumption' within that population. As the veterinary profession explores ways of addressing the emergence and selection of antimicrobial-resistant bacteria in food-producing animals, there is a need for veterinarians and producers to carefully consider all areas of antimicrobial use, and employ an evidence-based approach in designing appropriate clinical protocols. This paper aims to review current knowledge regarding the risk factors related to abdominal SSI in periparturient cows, and to encourage practitioners to judiciously evaluate both their standard operating procedures and their use of antimicrobials in these situations. In a second paper, to be published in a subsequent issue of Veterinary Record, these principles will be used to provide specific evidence-based recommendations for antimicrobial use in bovine abdominal surgery., (British Veterinary Association.)

Catfish is one of the most cultivated species worldwide. Antibiotics are usually used in catfish farming as therapeutic and prophylactic agents. In the USA, only oxytetracycline, a combination of sulfadimethoxine and ormetoprim, and florfenicol are approved by the Food Drug Administration for specific fish species (e.g., catfish and salmonids) and their specific diseases. Misuse of antibiotics as prophylactic agents in disease prevention, however, is common and contributes in the development of antibiotic resistance. Various studies had reported on antibiotic residues and/or resistance in farmed species, feral fish, water column, sediments, and, in a lesser content, among farm workers. Ninety percent of the world aquaculture production is carried out in developing countries, which lack regulations and enforcement on the use of antibiotics. Hence, efforts are needed to promote the development and enforcement of such a regulatory structure. Alternatives to antibiotics such as antibacterial vaccines, bacteriophages and their lysins, and probiotics have been applied to curtail the increasing emergence of antibiotic-resistant bacteria due to the imprudent application of antibiotics in aquaculture.

Pigs that die from pathogens associated with porcine respiratory disease complex (PRDC) in the late finishing period represent a significant economic wastage. While it is common to apply antimicrobial metaphylaxis (AM) to control PRDC, there are few studies exploring the potential cost-saving benefits of AM. In this study we examined the value of using AM in commercially reared, late finishing pigs, from farms with endemic PRDC. A total of 732 pigs from four AIAO wean to market sources, were blocked into 2 matching cohorts, based on enrollment body weight, sex, and rectal temperature. The cohorts received either control (C) or AM (Tulathromycin 2.5mg/kg IM, Zoetis, Florham Park, NJ, USA). Post treatment weight gain over the 21 day period was used as a measure of health and productivity. The AM treated pigs in the lowest weight quartile at enrollment, showed a significantly improved weight gain over controls (18.5 kg vs. 16.4 kg, mean difference=2.1 kg, CI 1.10-3.10, p=0.005) that was not evident in any other starting weight quartiles. These results indicate that the biological advantage and associated improvement in growth efficiency associated with the use of AM against PRDC, is only conferred to a specific sub-set of animals. The economic advantage of this strategy is therefore, only likely if the indicators of potential benefit (e.g., lighter weight cohort) can be reliably established. Further studies are needed to determine whether targeted AM could be effectively applied across the industry., (Copyright © 2015 Elsevier B.V. All rights reserved.)

There are no guidelines for antimicrobial use in experimental animals even though appropriate selection is required to reduce risk of surgical site infection (SSI) and resistance development. Pigs are used extensively as experimental surgical models for people. This review compares reported antimicrobial prescription in recently published pig surgical studies (retrieved by PubMed, Web of Knowledge and Google Scholar) with human guidelines for prophylactic antimicrobial use (National Institute of Clinical Excellence and the American Society of Health-System Pharmacists). A five-point appropriate antimicrobial use index (AAUI), based on aforementioned guidelines, was used to grade 233 studies. Use of World Health Organization-designated critically important antimicrobials (CIA) was recorded. Antimicrobial use was described in 111 of 233 (48 per cent) papers. AAUI scores of 5 (maximal compliance) and 0 (no compliance) were awarded to 34 (15 per cent) and 101 (43 per cent) articles. Where reported, prophylactic antimicrobials were mostly administered after surgery (62/95, 65 per cent) and intramuscularly (36/72, 50 per cent). CIAs were described in 21 of 111 (19 per cent) papers and SSIs in 21 of 233 (9 per cent). Reported antimicrobial prophylaxis in experimental pig surgery deviates from human clinical guidelines. This has implications for antimicrobial resistance, study quality and animal welfare. Until species-specific guidelines are formulated, experimental surgical studies involving animals would probably benefit from adherence to human guidelines., (British Veterinary Association.)

Objectives: To determine whether extending prophylactic antimicrobial administration into the postoperative period would decrease the surgical site infection (SSI) rate in clean canine orthopedic surgery associated with a metal implant., Study Design: Randomized prospective clinical study., Sample Population: Consecutive procedures (n = 400) on dogs that had clean orthopedic surgery using a metal implant., Methods: Cases were randomly allocated to 1 of 2 groups. Group 1 was only administered perioperative antimicrobial drugs whereas group 2 was administered perioperative and 5 days of postoperative antimicrobial therapy. Owners were questioned or dogs were examined at 2 and 6 weeks after surgery to identify any SSI. Long term follow-up by questionnaire of the referring veterinary surgeon ≥1 year after surgery was obtained., Results: Ten of 191 dogs (5.24%) in group 1 developed SSI within 6 weeks compared with 7 of 198 (3.54%) in group 2; 7.22% of dogs in group 1 and 8.24% in group 2 developed infections more than 6 weeks after surgery., Conclusions: SSI rates in this population of dogs were similar where antimicrobial prophylaxis was administered perioperatively over 3 hours or as a course continued for 6 days., (© Copyright 2015 by The American College of Veterinary Surgeons.)

Surgical site infections are among the complications that can be reduced with the timely implementation of appropriate antimicrobial therapy. A 3-D approach to judicious antimicrobial use focuses on the de-escalation of systemic antimicrobial therapy, design of dosing regimens, and decontamination of the surgeon, patient, and environment. De-escalation can be accomplished in part through proper antimicrobial prophylaxis. Dosing regimens should be designed to maximize efficacy and minimize resistance. Decontamination includes disinfection of inanimate surfaces and timely application of appropriate antiseptics at concentrations that maximize efficacy., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Zinc (Zn) is often supplemented at elevated concentrations in swine diets, particularly in piglets, to prevent enteric infections and promote growth. Previous studies from Denmark have suggested a genetic linkage and a phenotypic association between Zn resistance, encoded by czrC, and methicillin-resistance conferred by mecA in Staphylococcus aureus. Such an association has not been reported in the U.S. swine population. We conducted an analysis of the effects of Zn, supplemented as zinc oxide (ZnO), on the nasal carriage of methicillin-resistant Staphylococcus aureus (MRSA) in nursery (n=40) and finisher pigs (n=40) enrolled in a nutritional study. Nasal swabs, collected from nursery and finisher pigs, were inoculated onto MRSA CHROMagar and presumptive MRSA colonies were tested for the presence of mecA and czrC genes by polymerase chain reaction. Zinc susceptibility was determined by the agar dilution method. The prevalence of mecA-positive MRSA was 10% (4/40) and 20% (8/40) among nursery and finisher pigs, respectively. Of the 12 mecA-positive S. aureus isolates, 7 had the czrC gene (58.3%) compared to none among the 68 mecA-negative isolates. The presence of both mecA (p=0.002) and czrC (p=0.006) genes were positively associated with higher levels of Zn supplementation. The median minimum inhibitory concentrations of Zn for czrC-positive and czrC-negative isolates were 12 and 2 mM, respectively (p<0.0001). The link between czrC and mecA genes suggests the importance of elevated Zn supplementation in the co-selection and propagation of methicillin resistance among S. aureus in pigs.

Objective: To examine perioperative factors affecting surgical site infection (SSI) rate following tibial tuberosity advancement (TTA)., Study Design: Retrospective case series., Sample Population: 224 stifles in 186 dogs., Methods: Medical records of dogs that underwent TTA in a single institution were reviewed. Information on signalment, anaesthetic and surgical parameters, as well as occurrence of SSI was recorded. Dogs were followed for a minimum of three months postoperatively. The association between perioperative factors and SSI was assessed using Chi-squared tests and binary logistic regression., Results: The prevalence of SSI was 5.3% (12/224 TTA). Surgical time (p = 0.02) and anaesthesia time (p = 0.03) were significantly associated with SSI. For every minute increase in surgical time and anaesthesia time, the likelihood of developing SSI increased by seven percent and four percent respectively. The use of postoperative antimicrobial therapy was not significantly associated with lower SSI (p = 0.719). Implants were removed in 1.3% of cases (3/224 TTA)., Conclusions: The findings of this study suggest that increased surgical and anaesthesia times are significant risk factors for SSI in TTA, and that there is no evidence that postoperative prophylactic antimicrobial therapy is associated with SSI rate.

Objective: To discuss controversies surrounding antimicrobial use in critically ill horses., Data Sources: PubMed searches from 1970-present for terms including, but not limited to: "horse," "foal," "antimicrobial," "prophylaxis," "infection," "surgery," "sepsis," and "antimicrobial resistance.", Human Data Synthesis: Increasing bacterial antimicrobial resistance has changed first-line antimicrobial choices and prompted shortening of the duration of prophylactic and therapeutic treatment. The need to decrease bacterial resistance development to critically important antimicrobials has been highlighted., Veterinary Data Synthesis: Veterinary medicine has followed a similar trend but often without a high-level evidence. Common dilemmas include diseases in which the theoretically most effective drug is a reserved antimicrobial, the inability to differentiate infectious from noninfectious disease, the duration and necessity of prophylactic antimicrobials and use of antimicrobials in primary gastrointestinal disease. These problems are illustrated using examples of purulent infections, neonatal sepsis, colic surgery, and treatment of colitis. Although enrofloxacin, cephalosporins, and doxycycline, in contrast to gentamicin, reach therapeutic concentrations within the lungs of healthy horses, the first two should not be used as first line treatment due to their reserved status. Due to the high risk of bacterial sepsis, antimicrobial treatment remains indispensable in compromised neonatal foals but shortening the length of antimicrobial treatment might be prudent. One prospective randomized study demonstrated no difference between 3 and 5 days of perioperative antimicrobial treatment in colic surgery but shorter durations were not evaluated. High-level evidence to recommend antimicrobial treatment of adult horses with undifferentiated diarrhea does not exist., Conclusions: Few evidence-based recommendations can be made. Commonly used antimicrobial combinations remain the mainstay for treating purulent infections. Antimicrobial treatment for compromised foals should not extend beyond recovery. Continuation of prophylactic antimicrobials >3 days is likely unnecessary after colic surgery; shorter durations might be equally effective. Antimicrobial prophylaxis in adult horses with diarrhea is unlikely to be beneficial., (© Veterinary Emergency and Critical Care Society 2015.)

Bacteria entering the bloodstream via translocation from the gastrointestinal tract spread hematogenously and can trigger bacterial chondronecrosis with osteomyelitis (BCO) by infecting osteochondrotic microfractures in the epiphyseal-physeal cartilage of the proximal femora and tibiae. In experiment 1, broilers were fed control feed or the same feed containing BacPack 2X, which includes the prebiotic IMW50 (a mannan oligosaccharide beta-glucan yeast cell wall product) plus the probiotic Calsporin (Bacillus subtilis C-3102). Broilers reared on wire flooring consistently developed higher incidences of BCO than hatchmates reared on wood shavings litter (≥24 vs. ≤4%, respectively; P=0.001). Adding BacPack 2X to the feed on d 1 through 56 delayed the age of onset and reduced the cumulative incidence of BCO on wire flooring when compared with broilers fed the control feed (24.0 vs. 40.7%, respectively; P=0.003). In experiment 2, broilers reared on wire flooring received tap water on d 1 through 62 (control group) or therapeutic levels of the potent fluoroquinolone antimicrobial enrofloxacin in the water on d 35 through 54 (enrofloxacin group). During enrofloxacin administration, half as many birds developed BCO in the enrofloxacin group when compared with the control group (8.1 vs. 19.5%, respectively, on d 35 through 54; P=0.001), whereas both groups had similar BCO incidences subsequent to withdrawing enrofloxacin on d 55 through 62 (14.8 vs. 18.2% for the enrofloxacin vs. control groups; P=0.386). Cumulative lameness incidences for d 1 through 62 were higher for the control group than for the enrofloxacin group (39.0 vs. 25.8%, respectively; P=0.003). These results demonstrate that wire flooring imposes a rigorous challenge that leads to high incidences of BCO that can be difficult to suppress, even with therapeutic doses of enrofloxacin. Prophylactically adding BacPack 2X to the feed reduced the incidence of BCO lameness by a proportion similar to that achieved with enrofloxacin, indicating that probiotics potentially can provide effective alternatives to antibiotics for reducing BCO lameness attributable to bacterial translocation and hematogenous distribution., (© 2015 Poultry Science Association Inc.)

The objectives of this study were to 1) quantify effects of metaphylactic treatment for bovine respiratory disease (BRD) on growth performance, carcass characteristics, and lung lesion prevalence and severity; 2) evaluate the association of lung lesion prevalence and severity with carcass characteristics; and 3) evaluate effects of therapeutic treatment on carcass characteristics and lung lesion prevalence and severity. The study was conducted at a commercial feedlot in the Texas Panhandle in which steers (n = 2,336) initially weighing 312.1 ± 9.6 kg were sourced from auction markets and allocated in a randomized complete block design to 1 of 3 treatments (no metaphylactic [no antimicrobial drug {ND}] treatment, tilmicosin at 10 mg/kg BW [TIL], and tulathromycin at 2.5 mg/kg BW [TUL]). Lungs of all steers were evaluated during harvest to assess presence and severity of pneumonic lesions in the anteroventral lobes and the presence and severity of pleural adherences. Compared to the ND treatment, steers treated via metaphylactic therapy had greater (P < 0.05) metaphylactic cost, ADG, shrunk final BW, dressed carcass yield, HCW, 12th rib fat, calculated empty body fat (EBF), and gross revenue, concurrent with reduced (P < 0.05) BRD treatment costs and financial losses from BRD death and railed cattle, cumulatively resulting in greater financial returns. Lung lesions were present in 64.3% of lungs and were distributed similarly between metaphylactic treatments (63.9%) and ND (65.1%) cattle. Steers with advanced lung lesions present at harvest were associated with reduced (P < 0.05) HCW, KPH, 12th rib fat, calculated yield grades, marbling scores, and calculated EBF as compared to steers without lung lesions. Steers pulled for BRD had increased (P < 0.01) incidence of advanced lung lesions, mortality, and railers with decreased (P < 0.05) HCW, 12th rib fat, KPH, marbling score, calculated EBF, and percentage choice carcasses when compared to non-BRD event steers. From the results of this study, controlling BRD through the use of metaphylactic treatments on arrival in heavier cattle improved financial returns primarily driven by reductions in cost of death loss and railers.

This article discusses the clinically relevant uses of antimicrobials in small animal cancer patients. The article focuses on general considerations of antimicrobial use, antimicrobials in the neutropenic patient, prophylactic antimicrobial usage, antimicrobials in radiation therapy, and antimicrobials in metronomic chemotherapy protocols., (Copyright © 2014 Elsevier Inc. All rights reserved.)