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To describe the diagnosis and successful treatment of systemic francisellosis in a dog. An 11-year-old female spayed Labrador retriever presented for progressive lethargy, hyporexia, and cough. The dog was febrile with a neutrophilia, nonregenerative anemia, thrombocytopenia, and had increased activity in serum of liver-derived enzymes. Francisella philomiragia was isolated from aerobic blood culture. The dog was treated for 6 weeks with enrofloxacin orally. Repeated aerobic blood cultures after 2 and 6 weeks of antibiotic therapy were negative. The dog was clinically normal 7 months after diagnosis with no evidence of relapse., (© 2024 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals LLC on behalf of American College of Veterinary Internal Medicine.)

Background: The fecal bacterial microbiota of normal foals and foals with enterocolitis has been characterized using next-generation sequencing technology; however, there are no reports investigating the gut microbiota in foals hospitalized for other perinatal diseases., Objective: To describe and compare the fecal bacterial microbiota in healthy and sick foals using next-generation sequencing techniques., Animals: Hospitalized (17) and healthy foals (21)., Methods: Case-control study. Fecal samples were collected from healthy and sick foals on admission. Sick foals were further divided into sick nonseptic (SNS, n = 9) and septic (n = 8) foals. After extraction of DNA, the V4 region of the 16 S rRNA gene was amplified using a PCR assay, and the final product was sequenced with an Illumina MiSeq., Results: Diversity was significantly lower in healthy than sick foals (P < .05). The bacterial membership (Jaccard index) and structure (Yue & Clayton index) of the fecal microbiota of healthy, septic, and SNS foals were similar (AMOVA, P > .05). Bacterial membership (AMOVA, P = .06) and structure (AMOVA, P = .33) were not different between healthy and sick foals. Enterobacteriaceae, Enterococcus, and Streptococcus were among the 5 more abundant taxa identified in both groups., Conclusion and Clinical Importance: Higher fecal microbiota diversity in sick than healthy foals might suggest a high exposure to environmental microorganisms or an unstable colonic microbiota. The presence of microorganisms causing bacteremia in foals in a high relative abundance in the feces of foals suggests the intestine might play an essential role in the causation of bacteremia in foals., (© 2022 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals LLC on behalf of American College of Veterinary Internal Medicine.)

Background: Antimicrobial treatment protocols for foals with sepsis that do not improve clinically often are adjusted based on bacteriological and antimicrobial susceptibility testing results from samples collected at hospital admission., Objectives: To evaluate whether hospitalization for ≥48 hours affects bacteriological and antimicrobial susceptibility testing results., Animals: Two-hundred sixty-seven foals <30 days of age admitted to a neonatal intensive care unit and diagnosed with sepsis., Methods: Medical records were reviewed retrospectively to identify foals with sepsis and positive bacteriological cultures. Results from samples collected at hospital admission were compared to those collected ≥48 hours after admission. Logistic regression for clustered data and exact logistic regression were used for statistical analysis., Results: Three-hundred fifty-three unique bacterial isolates were obtained from 231 foals at hospital admission and 92 unique bacterial isolates were obtained from 57 foals after ≥48 hours of hospitalization. Relative isolation frequency after ≥48 hours of hospitalization increased for Acinetobacter spp., 0.6% versus 3.3% (odds ratio [OR], 7.63; 95% confidence interval [CI], 1.28-45.45); Enterococcus spp., 4.8% versus 19.6% (OR, 5.37; 95% CI, 2.64-10.90); Klebsiella spp., 5.1% versus 10.9% (OR, 2.27; 95% CI, 1.05-4.89); Pseudomonas spp., 3.0% versus 7.6% (OR, 3.49; 95% CI, 3.49-240.50); and Serratia spp., 3.0% versus 5.4% (OR, 20.23; 95% CI, 2.20-186.14). Bacteria isolated after ≥48 hours of hospitalization were less susceptible to all tested antimicrobial drugs, except for imipenem., Conclusions and Clinical Importance: Decreased antimicrobial susceptibility of bacteria isolated after ≥48 hours of hospitalization provides a rationale for repeated bacteriological culture and susceptibility testing in hospitalized foals with sepsis., (© 2020 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals, Inc. on behalf of the American College of Veterinary Internal Medicine.)

Background: Acute puerperal metritis (APM) affects 30% of postpartum dairy cattle. Bacteremia negatively impacts survival in cattle with coliform mastitis. However, the prevalence of bacteremia in dairy cattle with APM is unknown., Hypothesis: Bacteremia is detectable in a large proportion of cattle with APM., Animals: Seventeen dairy cows with APM and 17 healthy dairy cattle., Methods: Prospective case-control study. Cases were identified by daily monitoring of cattle in the first 10 days after calving. Controls were matched to cases by parity and days in milk. Cows were examined at the time of identification of APM. A complete blood count, serum biochemical analysis, and bacteriologic culture of blood and lochial fluid were performed on each animal at the time of diagnosis. The same samples were collected from healthy herdmates of a similar parity and days in milk. Blood culture results and clinicopathologic variables were compared between groups. Conditional logistic regression was used to evaluate factors associated with APM, whereas multivariate logistic regression was used to evaluate factors associated with bacteremia., Results: Bacteremia occurred in 53% (9/17) of cattle with APM and 53% (8/15) controls. Bacillus spp. was the organism most commonly isolated from the bloodstream in cattle of both groups. Bacteremic cattle in both groups were significantly less likely to have basophils in the peripheral circulation (P = .02) and more likely to have higher serum globulin concentrations (P = .02)., Conclusions and Clinical Importance: Bacteremia is a common occurrence in postpartum dairy cattle. Further study is warranted to investigate the modes by which bacteria colonize the bloodstream in this population of animals and the importance of bacteremia on health and productivity of affected animals., (Copyright © 2014 by the American College of Veterinary Internal Medicine.)

Background: Little is known about the specificity of Bartonella spp. immunofluorescent antibody (IFA) assays in dogs. Bacteremia in sick dogs most often has been associated with Bartonella henselae (Bh), Bartonella vinsonii subspecies berkhoffii (Bvb), and Bartonella koehlerae (Bk). Clarification of the diagnostic utility of IFA serology when testing against these organisms is needed., Objective: To evaluate the specificity of Bartonella IFA assays utilizing 6 cell culture-grown antigen preparations., Animals: Archived sera from SPF dogs (n = 29) and from dogs experimentally infected with Bvb (n = 10) and Bh (n = 3)., Methods: Antibodies (Abs) to Bvb genotypes I, II, and III, Bh serotype I, strains H-1 and SA2, and to Bk were determined by IFA testing., Results: Serum from naïve SPF dogs shown to be negative for Bartonella bacteremia did not react with any of the 6 Bartonella antigens by IFA testing. Dogs experimentally infected with Bvb genotype I developed Abs against homologous antigens, with no cross-reactivity to heterologous Bvb genotypes, Bh H-1, SA2 strains, or to Bk. Dogs experimentally infected with Bh serotype I developed Abs against Bh H-1, but not to Bh SA2 strain with no cross-reactive Abs to Bvb genotypes I-III or to Bk., Conclusions and Clinical Importance: Bartonella spp. Ab responses during acute experimental infections are species and type specific., (Copyright © 2013 by the American College of Veterinary Internal Medicine.)

Background: Bartonella species bacteremia has been identified in numerous animal species. These bacteria cause, or have been associated with, a spectrum of clinical manifestations in dogs and human patients. The frequency of exposure to or infection with Bartonella spp. among healthy and sick horses has not been reported., Objective: To test healthy and sick horses and sick foals from the southeastern United States for serological, microbiological, and molecular evidence of Bartonella infection., Animals: Forty-seven healthy horses, 15 sick foals, 22 horses with musculoskeletal manifestations, and 8 horses with colic were tested for Bartonella., Methods: IFA serology and PCR before and after BAPGM (Bartonella alpha-Proteobacteria Growth Medium) enrichment blood culture., Results: Bartonella antibodies were not detected in foals or horses. Three Bartonella species, B. henselae, B. vinsonii subsp. berkhoffii (genotypes I and III), and a Bartonella species with closest homology to Candidatus Bartonella volans, were PCR-amplified and sequenced from blood or BAPGM enrichment blood culture samples from 1/47 healthy horses, 3/15 sick foals, 5/22 horses with musculoskeletal disease, and 0/8 horses with colic., Conclusions and Clinical Importance: Horses in the southeastern United States are naturally infected with B. henselae, B. vinsonii subsp. berkhofii genotypes I and III, and a bacteria most similar to Candidatus Bartonella volans. Antibodies were not detectable by indirect fluorescent antibody assay (IFA) testing in bacteremic foals or horses, and prolonged enrichment culture for periods up to 21 days were necessary to document bacteremia in most horses. Further investigation into the pathogenic potential of Bartonella spp. infection in horses is warranted., (Copyright © 2012 by the American College of Veterinary Internal Medicine.)

Background: Experimental infection of horses with Bartonella species is not documented., Objectives: Determine clinical signs, hematologic changes, duration of bacteremia, and pattern of seroconversion in Bartonella henselae or Bartonella bovis-inoculated horses., Animals: Twelve (2 groups of 6) randomly selected healthy adult horses seronegative and culture negative for Bartonella spp., Methods: Experimental/observational study: Group I: B. henselae or saline control was inoculated intradermally into 4 naïve and 2 sentinel horses, respectively. Group II: same design was followed by means of B. bovis. Daily physical examinations, once weekly CBC, immunofluorescent antibody assay serology, real-time polymerase chain reaction (PCR), and twice weekly blood cultures were performed for 6 weeks and at postinoculation day 80 and 139. Bartonella alpha-Proteobacteria growth medium (BAPGM) enrichment blood culture was performed for horses that seroconverted to B. henselae antigens., Results: Transient clinical signs consistent with bartonellosis occurred in some Bartonella-inoculated horses, but hematological alterations did not occur. Three B. henselae-inoculated horses seroconverted, whereas 1 B. bovis-inoculated horse was weakly seropositive. In Group I, B. henselae was amplified and sequenced from BAPGM blood culture as well as a subculture isolate from 1 horse, blood from a 2nd horse, and BAPGM blood culture from a 3rd horse although a subculture isolate was not obtained. All sentinels remained PCR, culture, and serology negative., Conclusions: Detection of Bartonella sp. in blood after experimental inoculation supports bacteremia and seroconversion. Culture with BAPGM may be required to detect Bartonella sp. Although mild clinical signs followed acute infection, no long-term effects were noted for 2 years postinoculation., (Copyright © 2012 by the American College of Veterinary Internal Medicine.)

Background: Identification of the bacterial organism in dogs with endocarditis is challenging. Human studies have reported the utility of the polymerase chain reaction (PCR) to amplify and identify bacterial nucleic acid from infected valvular tissue and blood., Hypothesis/objectives: We hypothesized that PCR using primers designed to amplify the bacterial 16s gene would identify circulating bacteria in dogs with suspected bacterial endocarditis more consistently than standard blood culture techniques., Animals: Eighteen dogs with suspected bacterial endocarditis based upon clinical and echocardiographic findings. Fifteen clinically normal dogs served as negative controls., Methods: Prospective study of dogs evaluated for suspect endocarditis at 6 veterinary hospitals. A blood sample was drawn from all dogs and evaluated with both a single-sample PCR and standard 3-sample blood culture techniques., Results: Blood culture identified noncontaminant bacteria in 6/18 study animals (33%) and 1 control dog; PCR identified noncontaminant bacteria in 7/18 study animals (39%). There were no study animals in which the 2 tests identified different bacteria (κ = 1.0). However, bacteria were identified by both techniques in only 2/18 study animals. When results from both PCR and blood culture were considered together, a noncontaminant bacterial organism was identified in 11/18 study animals (61%)., Conclusion and Clinical Importance: The results of this study suggest that although single sample PCR with 16s primers was not more sensitive than blood culture for detection of bacteremia in dogs with suspect endocarditis, performing both techniques simultaneously did increase the likelihood of identification of bacteria in blood., (Copyright © 2011 by the American College of Veterinary Internal Medicine.)

Background: Bacteremia occurs frequently in newborn calves. The predictive value of clinical signs is low, suggesting the use of calf-side diagnostic tests., Objectives: To investigate testing of urine catalase activity (Uriscreen test) for bacteriuria and bacteremia detection., Animals: Five colostrum-free calves and 3 colostrum-fed control calves., Methods: Controlled experimental trial. Colostrum-free calves were inoculated PO with Escherichia coli O78+. A clinical score was established to define the onset of the illness. Blood and urine (cystocentesis) samplings and cultures, and Uriscreen tests, were performed 4-6 times from inoculation to death. Three control calves received the same management as 3 inoculated calves, but with colostrum and without inoculation., Results: Bacteremia was demonstrated in all of the inoculated colostrum-free calves and in none of the control calves. The E. coli O78+ strain, E. coli, and Klebsiella spp. were recovered from 4/5, 5/5, and 2/5 inoculated colostrum-free calves, respectively. Urine cultures were negative for the 2 groups at the start of the experiment; 5/5 colostrum-deprived inoculated calves were positive for E. coli thereafter whereas 3/3 controls remained negative. Concordance of Uriscreen tests with bacteremia and bacteriuria was 0.86 and 0.88, respectively. Kappa value of agreement between Uriscreen and bacteremia and bacteriuria was 0.73 and 0.76, respectively. Sensitivity of Uriscreen for bacteremia and bacteriuria was 80.0 and 86.6%, respectively, and specificity was 92.8 and 88.8%, respectively., Conclusions and Clinical Relevance: The results suggest that Uriscreen can be used for detection of bacteremia in neonatal calves in connection with a constant bacteriuria., (Copyright © 2010 by the American College of Veterinary Internal Medicine.)

Background: Bacteremia in sick foals is associated with survival, but the association of bacteremia and diarrhea is not reported., Hypothesis: Neonatal foals with diarrhea will commonly be bacteremic., Animals: One hundred and thirty-three neonatal foals., Methods: Records of all foals <30 days of age presenting with diarrhea between January 1990 and September 2007 were reviewed., Results: Sixty-six of 133 foals (50%) were bacteremic at admission, with 75 isolates from the 66 samples. The blood culture from a further 18 foals (13.5%) grew coryneform bacteria. Nine foals (6.8%) had 2 or more organisms grown on blood culture. One foal had 5 different organisms, interpreted as contamination. Forty-eight foals (36%) had no growth on admission blood cultures. No cultures isolated fungal organisms. Excluding coryneform bacteria, 43 isolates (57%) were Gram-negative organisms and 32 isolates (43%) were Gram-positive organisms. The most common isolate was Enterococcus spp. (22 isolates, 29%), followed by Pantoea agglomerans (13 isolates, 17%). IgG concentration at admission was not associated with blood culture status. Blood culture status was not associated with survival to hospital discharge., Conclusions and Clinical Importance: Bacteremia is common in neonatal foals with diarrhea. Decisions regarding antimicrobial selection should be made with these differences in mind.

Background: Bartonella spp. are emerging zoonotic agents that have been found in a wide variety of domestic animals and wildlife and cause a number of clinical syndromes. Bartonella sp. infection has been identified in a growing number of animal species, including cats, rodents, porpoises, and canids, but has not been reported in horses., Objective: To document the presence of Bartonella sp. in the blood of horses., Animals: One horse with chronic arthropathy and 1 horse with presumptive vasculitis., Methods: Blood samples were tested for the presence of Bartonella sp. by a combination of multiplex real-time polymerase chain reaction and enrichment culture technique., Results: Bartonella henselae was isolated or detected in the blood of both horses., Conclusion and Clinical Importance: Bartonella henselae infection should be investigated as the cause of disease in horses.

The objectives of this study were to investigate the pharmacokinetics of once-daily amikacin in healthy neonates, to determine amikacin concentrations in hospitalized foals, and to determine the minimum inhibitory concentrations (MICs) of amikacin against gram-negative isolates from blood cultures in septic foals. Median half-life, clearance, and volume of distribution of amikacin in healthy 2- to 3-day-old foals after administration of an intravenous bolus of amikacin (25 mg/kg) were 5.07 hours (4.86-5.45 hours), 1.82 mL/min/kg (1.35-1.97 mL/min/kg), and 0.785 L/kg (0.638-0.862 L/kg), respectively. Statistically significant (P <.05) decreases in area under the curve (14% decrease), mean residence time (19% decrease), and C24h plasma amikacin concentrations (29% decrease) occurred between days 2-3 and 10-11. Plasma amikacin concentrations in healthy foals at 0.5 hours (C0.5h) were significantly higher (P = .02) than those of hospitalized foals. Sepsis, prematurity, and hypoxemia did not alter amikacin concentrations. The MIC at which 90% of all gram-negative isolates from equine neonatal blood cultures were inhibited by amikacin was 4 microg/mL, suggesting that amikacin C0.5h of 40 microg/mL should be targeted to achieve a maximum serum concentration to MIC ratio of 10:1. The proportion of foals with C0.5h 40 microg/mL was significantly higher (P < .0001) in hospitalized foals receiving a dose of amikacin at 25 mg/kg (22/24 or 92%) than in foals receiving a dose at 21 mg/kg (9/25 or 36%), whereas no difference was found in the proportion of foals with C24h concentrations > or = 3 microg/mL between the 2 groups. An initial dose at 25 mg/kg is recommended for once-daily amikacin in equine neonates.

Medical records of 101 blood culture-confirmed bacteremic foals were reviewed to determine whether foals with Actinobacillus sp. bacteremia are affected at an earlier age, have more severe signs of disease, and have a worse prognosis than do foals with bacteremia of other causes. Thirty percent (30/101) of bacteremic foals had Actinobacillus sp. cultured, and these were 2 times more likely to die (crude odds ratio [OR(CR)] 0.8, 4; P = .14), with a survival rate of 43% (13/30) compared to the overall survival rate of 55% (56/101). When compared to other bacteremic foals, foals with actinobacillosis were 7 times more likely to have been sick from birth (adjusted odds ratio [OR(ADJ)] 2, 26; P = .003) and 6 times more likely to have diarrhea (OR(ADJ) 1, 22; P = .009). By bivariate analysis. foals with Actinobacillus sp. bacteremia were 5 times more likely to have a sepsis score >11 (OR(CR) 1, 18; P = .007), 6 times more likely to be obtunded (OR(CR) 2, 20; P = .005), and 3 times more likely to have pneumonia (OR(CR) 1, 7; P = .03). Furthermore, Actinobacillus sp. bacteremic foals were 27 times more likely to have a segmented neutrophil count <3.3 X 10(9) cells/L (OR(ADJ) 4, 166: P < .0001) and were 4.5 times more likely to have a band neutrophil count >0.46 x 10(9) cells/L (OR(ADJ) 1, 17; P = .02) when compared to foals that had bacteremia caused by either gram-negative enteric or gram-positive organisms. Sepsis score was < or = 11 in 49% (29/59) of bacteremia foals aged <13 days for which a discernible sepsis score was calculable. Results of this study should improve the diagnostic sensitivity of clinical examinations of neonatal foals, thereby facilitating treatment decisions.

Physical examination and clinicopathologic findings from 44 adult Holstein cows with naturally occurring coliform mastitis were studied. The cattle were grouped for comparison by stage of lactation and survival. Cattle within the first 4 weeks of lactation maintained higher median mature neutrophil counts (1,200 versus 300/microL) in peripheral blood than cattle later in lactation. Nonsurviving cows had higher median creatinine concentration (2.5 versus 1.6 mg/dL) and anion gap (25 versus 20 mEq/L), and lower serum protein (7.1 versus 7.6 gm/dL) and total CO2 (19.8 versus 25 mEq/L) concentrations than surviving cows (P < .05). These findings indicate that cattle with uremia and metabolic acidosis are less likely to survive the infection. Bacteriologic blood cultures were performed on 34 of the 44 cows studied. Escherichia coli was isolated from the blood in 11 (32%) cows. Clinical presentation and clinicopathologic data were compared in bacteremic versus nonbacteremic cows to evaluate these data as predictors of bacteremia. Bacteremic cows were sick longer prior to admission (2 versus 1 days), maintained higher median counts of total nucleated cells (6.6 versus 2.4 x 10(3) cells/microL), myelocytes (0.2 versus 0 x 10(3) cells/microL), metamyelocytes (0.5 versus 0.02 x 10(3) cells/microL), band neutrophils (0.7 versus 0.1 x 10(3) cells/microL), and lymphocytes (2.1 versus 1.4 x 10(3) cells/microL) than nonbacteremic cows, and had higher plasma fibrinogen concentration (600 versus 500 mg/dL) (P < .05). There were no differences between the physical or serum biochemical measurements. Four of 11 bacteremic cows and 5 of 23 nonbacteremic cows died or were euthanized (P > .05). The high prevalence of bacteremia seen in cows with coliform mastitis has not been reported previously, and may have been due to the duration of disease, severity of signs, or culture technique. These findings suggest that systemic antibiotic therapy may be beneficial in some severe cases of coliform mastitis.

Eight normal ponies placed in direct contact with ponies experimentally infected with Ehrlichia risticii for 30 to 90 days did not develop signs of Potomac horse fever. They also did not seroconvert, and they remained susceptible to IV infection. One of 8 ponies that were force fed fresh feces from infected ponies while in direct contact with ponies experimentally infected with E. risticii developed Potomac horse fever and seroconverted. The other 7 remained asymptomatic, did not seroconvert, and were susceptible to IV infection. Six of 9 ponies inoculated with E. risticii via nasogastric intubation and oral drench developed Potomac horse fever and seroconverted. The other 3 remained asymptomatic and did not seroconvert. One of these latter ponies and 2 normal ponies that were inoculated via oral drench only developed Potomac horse fever and seroconverted. The high fever, maximum clinical score for decreased feed intake, depressed mental attitude, decreased borborygmal sounds, severity of diarrhea, and the length of illness of the orally infected ponies was not significantly different from those of IV infected control ponies, although the signs occurred significantly later (P < .05).

Plasma endotoxin concentrations were measured at 1 to 2 and 5 to 6 days of age in clinically normal foals and in potentially septic neonatal foals admitted to North Carolina State University's Veterinary Teaching Hospital for a variety of conditions. In 1 to 2 and 5 to 6 day old normal foals, median plasma endotoxin concentrations were 2.17 (range, 1.61-2.54; n = 6) and 2.89 (range, 2.61-3.50; n = 7) endotoxin units/mL (EU/mL), respectively. Median plasma endotoxin concentration in potentially septic foals with negative blood cultures or gram positive isolates (n = 8) was 2.73 (range, 0.59-4.04) EU/mL. In hospitalized foals with gram negative isolates (n = 6), median plasma endotoxin concentration was 78.06 (range, 0.76-2,696.41) EU/mL, but individual endotoxin values were only increased in foals that were extremely sick and died within hours of sampling. Plasma endotoxin concentrations were significantly greater in foals with sepsis scores > or = 11 compared with foals with sepsis scores < or = 10. Increased plasma endotoxin concentrations appear to predict an unfavorable outcome in septic foals, but normal endotoxin concentrations do not appear to have any predictive value.