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Introduction. Dalbavancin was approved in Europe in 2015 for skin and soft tissue infections. Hypothesis/Gap Statement. Data on methicillin-resistant coagulase-negative staphylococci (MR-CNS) dalbavancin susceptibility are scarce. Aim. To assess the susceptibility of MR-CNS to dalbavancin and other anti-staphylococcal agents. Methodology. A total of 443 MR-CNS clinical isolates from patients hospitalized in a Greek university hospital during a 2.5-year period (January 2018 to June 2020) were included. The MICs for vancomycin, teicoplanin, linezolid and daptomycin were investigated by Etest and the MIC for dalbavancin was determined according to European Committee on Antimicrobial Susceptibility Testing (EUCAST) guidelines in 196 isolates. The consumption of the aforementioned antimicrobials was calculated. Results. In total, 51 isolates were resistant to teicoplanin (11.5 %) and 211 (47.6 %) to linezolid; all were susceptible to vancomycin and daptomycin. Among 196 isolates tested, 32 (16.3 %) were resistant to dalbavancin. A significant increase of MIC during the study period was found for vancomycin, teicoplanin and daptomycin, while a decrease in linezolid's MIC was observed. Dalbavancin's MIC remained stable. No difference in consumption was observed among the studied anti-staphylococcal agents. Conclusion. An increase of vancomycin, teicoplanin and daptomycin MICs among MR-CNS was observed, whereas 47.6 % of isolates were non-susceptible to linezolid. Dalbavancin retains excellent potency against MR-CNS, even in the presence of non-susceptibility to other anti-staphylococcal antibiotics.

Background: Vancomycin resistant enterococci (VRE) and vancomycin resistance coagulase negative staphylococci (VRCoNS) are common pathogens causing difficult to treat health care associated infections (HAI). Hence, the World Health Organization listed VRE as one of the high priority pathogens for new antibiotic discovery and antimicrobial resistance surveillance. Despite this, data on the prevalence of VRE and VRCoNS in Ethiopia is scarce. Thus, the present study determined prevalence of VRE and VRCoNS among patients attending Felege-Hiwot comprehensive specialized hospital, Ethiopia., Methods: A hospital based cross-sectional study was conducted on 384 patients selected conveniently from February to March 2020. Data on demographic and clinical variables were collected using a structured questionnaire by face-to-face interview. Simultaneously urine, venous blood and wound swab were collected and processed following standard bacteriological technique. Antimicrobial susceptibility test was performed by minimum inhibitory concentration method using E-test for vancomycin and Kirby-Bauer disc diffusion method for other classes of antibiotics. Data was entered and analyzed using SPSS version 23. Logistic regression was performed to identify factors associated with VRE infection. P. value < 0.05 was considered as statistically significant., Results: The prevalence of enterococci and CoNS were 6.8% and 12% respectively. The prevalence of VRE was 34.61% (9/26), while all CoNS (46 isolates) were susceptible to vancomycin. The majority (66.7%) of VRE was isolated from blood samples. Furthermore all VRE (100%), 58.8% of vancomycin susceptible enterococci and 45.7% of CoNS were multidrug resistant (MDR). Having educational level of secondary school and below (AOR = 12.80, CI = 1.149-142.5), previous exposure to catheterization (AOR = 56.0, CI = 4.331-724.0) and previous antibiotic use practice (AOR = 26.25, CI = 3.041-226.2) were a significant associated explanatory factor for VRE infection., Conclusions: The prevalence of vancomycin resistance enterococci, which is also multidrug resistant, was significantly high. Though no vancomycin resistance CoNS detected, the MDR level of CoNS was high. Thus to limit enterococci and CoNS infections and MDR development, focused infection prevention measures should be implemented., Competing Interests: The authors have declared that no competing interests exist

Coagulase-negative staphylococci and Staphylococcus aureus colonize similar niches in mammals and conceivably compete for space and nutrients. Here, we report that a coagulase-negative staphylococcus, Staphylococcus chromogenes ATCC43764, synthesizes and secretes 6-thioguanine (6-TG), a purine analog that suppresses S. aureus growth by inhibiting de novo purine biosynthesis. We identify a 6-TG biosynthetic gene cluster in S. chromogenes and other coagulase-negative staphylococci including S. epidermidis, S. pseudintermedius and S. capitis. Recombinant S. aureus strains harbouring this operon produce 6-TG and, when used in subcutaneous co-infections in mice with virulent S. aureus USA300, protect the host from necrotic lesion formation. Used prophylactically, 6-TG reduces necrotic skin lesions in mice infected with USA300, and this effect is mediated by abrogation of toxin production. RNAseq analyses reveal that 6-TG downregulates expression of genes coding for purine biosynthesis, the accessory gene regulator (agr) and ribosomal proteins in S. aureus, providing an explanation for its effect on toxin production.

Introduction. Coagulase-negative staphylococci have been recognized both as emerging pathogens and contaminants of clinical samples. High-resolution genomic investigation may provide insights into their clinical significance. Aims. To review the literature regarding coagulase-negative staphylococcal infection and the utility of genomic methods to aid diagnosis and management, and to identify promising areas for future research. Methodology. We searched Google Scholar with the terms ( Staphylococcus ) AND (sequencing OR (infection)). We prioritized papers that addressed coagulase-negative staphylococci, genomic analysis, or infection. Results. A number of studies have investigated specimen-related, phenotypic and genetic factors associated with colonization, infection and virulence, but diagnosis remains problematic. Conclusion. Genomic investigation provides insights into the genetic diversity and natural history of colonization and infection. Such information allows the development of new methodologies to identify and compare relatedness and predict antimicrobial resistance. Future clinical studies that employ suitable sampling frames coupled with the application of high-resolution whole-genome sequencing may aid the development of more discriminatory diagnostic approaches to coagulase-staphylococcal infection.

Coagulase-negative staphylococci (CoNS) are frequently isolated from wound infections. There are limited data examining the prevalence of methicillin-resistant CoNS (MRCoNS) among Egyptian patients after surgery. Thus, we studied 208 hospitalised patients, who had skin and soft tissue infections (SSTIs) due to various causes. Samples were cultured for isolation and identification of CoNS and isolates were screened for susceptibility against 23 different antimicrobials. Out of 241 Staphylococcal isolates, 114 (47.3%) were CoNS. The prevalence of MRCoNS among surgical site infection, diabetic foot, abscess, and burn patients was 13.4%, 11.5%, 15.6%, and 10.3%, respectively. The lowest resistance of the 27 identified MRCoNS isolates was to vancomycin, amikacin and gatifloxacin (7% each). We conclude that CoNS isolates are major pathogens associated with wound infections at our institution and MRCoNS probably poses a substantial threat for patients in Egypt, though most MRCoNS isolates demonstrated susceptibility to vancomycin.

Background: Staphylococci species are the major constituents of infectious bioaerosols, particularly methicillin-resistant Staphylococci (MRS) have serious health impacts. Here, the bacterial burden was quantified, especially prevalence of MRS in bioaerosols collected from indoors of Dr. B.R. Ambedkar Central Library (DBRACL) and Central Laboratory Animal Resources (CLAR) of Jawaharlal Nehru University, New Delhi, India. Air samplings from DBRACL and CLAR were done using the settle plate method and SKC biosampler, respectively., Results: This study showed a maximum 6757 CFU/m 2 /hr of bacterial load in the DBRACL reading room, while unacceptable bacterial loads (> 1000 CFU/m 3 of air) at different sites of CLAR. Further, at both the sampling sites the predominance of coagulase negative Staphylococci (CNS) was observed. A total 22 and 35 Staphylococci isolates were isolated from DBRACL and CLAR bioaerosols, respectively. Majority (16/22) of the Staphylococcal isolates from DBRACL belonged to human-associated Staphylococci where S. haemolyticus (5/22) was the most dominating species. However, in CLAR facility centre, animal-associated Staphylococci (19/35) were dominating, where S. xylosus (12/35) was the most dominating species. Further, antibiotic sensitivity tests revealed 41% MRS and 73% multidrug resistant (MDR) among airborne Staphylococci from DBRACL indoor bioaerosols. Similarly, in CLAR facility, approximately, 66% Staphylococci isolates were methicillin resistant, out of which 2 isolates showed high MIC value ≥ 16 μg/mL. Further, we confirmed the presence of 49% multidrug resistant Staphylococci in the indoor air of CLAR facility., Conclusions: This study suggested that the exposure of workers and students in CLAR to such a high concentration of drug-resistant Staphylococci should not be undermined, as these bacterial concentrations are the direct representative of inhalable particulate matter (PM 2.5 ) as per collection procedure. Simultaneously, passive sampling from DBRACL assessed the risks due to microbial contamination in particle agglomerates, which may deposit on the crucial surfaces such as wounds/ cuts or on the frequently used items.

This study compared changes in antimicrobial susceptibilities and molecular characteristics of coagulase-negative staphylococci (CNS) between the year 2000 and the year 2014-2015 to evaluate the policy of separating drug prescribing and dispensing in Korea. We obtained 68 CNS clinical isolates from two tertiary general hospitals before (the year 2000; n  = 25) and after (the year 2014 - 2015; n  = 43) implementation of the separation. Isolates were identified as Staphylococcus capitis , Staphylococcus epidermidis , Staphylococcus haemolyticus , Staphylococcus hominis , Staphylococcus saprophyticus , and Staphylococcus warneri. When minimal inhibitory concentrations of 14 antimicrobials were applied to isolates, resistance rates to gentamicin and oxacillin in 2000 were significantly higher than in 2014-2015 ( p  < 0.05). Fifty-seven isolates were methicillin-resistant CNS (MR-CNS), 42 of which were also multidrug resistant; overall, multidrug resistance decreased from 72% in the year 2000 to 55.8% in 2014-2015. Staphylococcal cassette chromosome mec (SCC mec ) type III was the dominant type of MR-CNS in the year 2000, while SCC mec type IV was the dominant type in 2014-2015. Twenty-five sequence types (STs) were identified; ST2 appeared most frequently in both periods. After 15 years of implementation of this policy, multidrug resistance as well as methicillin and gentamicin resistance in CNS decreased, but not resistance to other antibiotics. Long-term surveillance at both genotypic and phenotypic levels of various species is necessary for further evaluation of this policy.

The intestinal microbiota has enormous impact on the health and performance of horses. Staphylococci belong in the phylum Firmicutes, and their occurrence, especially of methicillin-resistant strains and species, has been reported in horses previously. Moreover, biofilm formation is one of the virulence factors; it has been not completely studied in fecal coagulase-negative staphylococci (CoNS) from horses. Therefore, this study was focused on biofilm formation by various species of fecal CoNS from horses because it has been never reported before. In addition, their antibiotic profile was tested. Horses (42) of various breeds from Slovakia/Poland were sampled. Variability in the species of CoNS was detected in feces of horses. Thirty-two strains were identified by using the MALDI-TOF system and classified into nine species and three subspecies of CoNS: Staphylococcus capitis, S. cohnii subsp. cohnii, S. cohnii subsp. urealyticus, S. cohnii subsp. casei, S. epidermidis, S. haemolyticus, S. pasteuri, S. sciuri, S. vitulinus, S. warneri, and S. xylosus. The most frequent species was S. vitulinus. Twenty-two strains showed high biofilm production; 10 strains showed low-grade biofilm production. The highest biofilm formation was measured in the species S. xylosus. Eleven strains (of 32) were methicillin-resistant; the others were susceptible to methicillin.

The antibiotic resistance among coagulase - negative Staphylococcus (CoNS) species towards methicillin is rarely reported in veterinary medicine. Under the aspect/concept of One Health, those strains pose a risk to human health due to the presence in canine pets where the transfer of resistant genetic markers might occur to other staphylococci species. The aim of this study was to investigate the antimicrobial resistance pattern among Coagulase Negative Staphylococci (CoNS) isolated from asymptomatic dogs and those affected by topic infections. Swabs from 254 dogs were first seeded in Mannitol Salt Agar. Species identification was conducted by Matrix Assisted Laser Desorption ionization - time of flight (MALDI-TOF ms) as previously described. The susceptibility test was performed by disk diffusion according to CLSI standards. Detection of mecA gene was performed. CoNS could be recovered from both groups of dogs and an alarming presence of methicillin-resistant coagulase negative staphylococci (MRCoNS) was confirmed, in 10.2% (17/166) of the samples. Eight of those methicillin resistant strains were isolated from asymptomatic dogs whereas nine were present in dogs affected by pyoderma and otitis externa., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Background: Progress in contemporary medicine is associated with an increasing number of immunocompromised individuals. In this vulnerable group, the underlying disease together with long-term hospitalization and the use of medical devices facilitate infections by opportunistic pathogens, of which coagulase-negative staphylococci (CoNS) represent a prime example., Objectives: The diversity of CoNS with species- and strain-specific differences concerning virulence and clinical impact is highlighted. A focus is on the ability of CoNS to generate biofilms on biotic and abiotic surfaces, which enables skin and mucosa colonization as well as establishment of CoNS on indwelling foreign bodies., Sources: Literature about the virulence of CoNS listed in PubMed was reviewed., Content: Most catheter-related and prosthetic joint infections as well as most other device-related infections are caused by CoNS, specifically by Staphylococcus epidermidis and Staphylococcus haemolyticus. A common theme of CoNS infections is a high antibiotic resistance rate, which often limits treatment options and contributes to the significant health and economic burden imposed by CoNS., Implications: Breaching the skin barrier along with the insertion of medical devices offers CoNS opportunities to gain access to host tissues and to sustain there by forming biofilms on foreign body surfaces. Biofilms represent the perfect niche to protect CoNS from both the host immune response and the action of antibiotics. Their particular lifestyle, combined with conditions that facilitate host colonization and infection, has led to the growing impact of CoNS as pathogens. Moreover, CoNS may serve as hidden reservoirs for antibiotic resistance and virulence traits., (Copyright © 2018 European Society of Clinical Microbiology and Infectious Diseases. Published by Elsevier Ltd. All rights reserved.)

CoNS is the main cause of catheter-related bloodstream infections (CRBSI). Current guidelines recommend catheter withdrawal followed by antibiotics for at least 5 days. We aimed to assess the efficacy and safety of a shorter course of antibiotherapy in patients with CoNS CRBSI. All proven cases of CoNS CRBSI at our institution (Jan 12/Dec 17) were retrospectively analysed. Comparison of clinical characteristics and outcomes between patients receiving a short (SC ≤ 3 days) versus long antibiotic course (LC > 3 days) was performed. Cox regression models predicting the risk for complications (including propensity score [PS] for treatment assignment as covariate) were designed to adjust baseline differences among both treatment groups. A total of 79 cases were included. Most patients (75.9%) showed clinical response at day 7 after catheter removal. Complications occurred in 3.8% (three cases of septic thrombophlebitis) with no cases of endocarditis. Microbiological relapse (MR) occurred in 13 patients (16.5%). SC and LC were administered to 25 (31.6%) and 54 (68.4%) patients, respectively, with no significant differences in MR-free survival between SC and LC groups (87.8 vs 86.3%; P = 0.6). In PS-adjusted Cox regression analyses, a tunnelled catheter as the source of CRBSI was the only independent risk factor for MR (hazard ratio, 5.71; 95% confidence interval, 1.6-21) whereas the duration of therapy had no apparent impact. Shortening antibiotic therapy to ≤ 3 days is not associated with a poorer outcome or a greater risk of MR in patients with CoNS CRBI with catheter withdrawal.

Coagulase-negative Staphylococci (CoNS) are skin commensal bacteria. Besides their role in maintaining homeostasis, CoNS have emerged as major pathogens in nosocomial settings. Several studies have investigated the molecular basis for this emergence and identified multiple putative virulence factors with regards to Staphylococcus aureus pathogenicity. In the last decade, numerous CoNS whole-genome sequences have been released, leading to the identification of numerous putative virulence factors. Koch's postulates and the molecular rendition of these postulates, established by Stanley Falkow in 1988, do not explain the microbial pathogenicity of CoNS. However, whole-genome sequence data has shed new light on CoNS pathogenicity. In this review, we analyzed the contribution of genomics in defining CoNS virulence, focusing on the most frequent and pathogenic CoNS species: S. epidermidis , S. haemolyticus, S. saprophyticus , S. capitis , and S. lugdunensis .

Staphylococcus lugdunensis and Staphylococcus haemolyticus are unique among CoNS in that the former often causes aggressive disease, while the latter consistently exhibits high rates of multidrug resistance. We evaluated the in vitro susceptibility of contemporary (2012-2013) isolates from both pathogens to tedizolid and comparators, using standard methodology. Results were interpreted using CLSI and EUCAST breakpoints. Overall, 106 S. lugdunensis and 103 S. haemolyticus isolates were collected from 51 medical centers in the United States and 30 centers in 18 European countries. Tedizolid showed good activity against S. lugdunensis (MIC 50 /MIC 90 : 0.12/0.12 mg/L) and S. haemolyticus (MIC 50 /MIC 90 : 0.12/0.12 mg/L), inhibiting all isolates at MIC ≤0.25 mg/L. Based on the EUCAST breakpoint for staphylococci and when substituting the CLSI breakpoint for Staphylococcus aureus, all isolates were tedizolid susceptible. All isolates were also susceptible to linezolid, but the in vitro potency of tedizolid was 4-fold greater than that of linezolid against both S. lugdunensis and S. haemolyticus, based on MIC 90 values. S. lugdunensis exhibited ≥99% susceptibility to vancomycin, teicoplanin, gentamicin, levofloxacin, and trimethoprim-sulfamethoxazole; 7% of isolates were resistant to tetracycline, 11% to clindamycin, and 2% were methicillin-resistant. S. haemolyticus exhibited high rates of resistance to commonly used anti-staphylococcal agents: 71% of isolates were resistant to methicillin, 36%-37% to clindamycin, and 30%-50% to gentamicin. These in vitro findings suggest that tedizolid could be an alternative treatment option for infections due to these medically important CoNS pathogens. Additional clinical evaluation and continued surveillance of tedizolid in vitro activity against S. lugdunensis and S. haemolyticus are warranted., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Objective: To evaluate the impact of rapidly identifying coagulase-negative staphylococci (CoNS) from positive blood cultures combined with an established antimicrobial stewardship (AS) programme at a tertiary cancer centre., Methods: We compared cancer patients ≥18 years old who between 01/1/13 and 12/31/13 had one or more positive CoNS blood culture(s) identified by Staphylococcus QuickFISH® (a peptide nucleic acid fluorescence in situ hybridization assay) with cancer patients ≥18 years old who had CoNS identified by standard microbiological techniques between 01/01/11 and 12/31/11 (baseline). Positive blood culture results were reported to the clinician by microbiology staff; restricted antibiotics (e.g., vancomycin) required approval by the AS team., Results: There were 196 baseline and 103 QuickFISH patients. Faster median time to organism identification (33 (IQR 27-46) versus 49 (IQR 39-63) hours, p < 0.001), more vancomycin avoidance (51/103 (50%) versus 60/196 (31%), p 0.002), shorter median antibiotic duration (1 (IQR 0-3) versus 2 (IQR 0-6) days, p 0.019), fewer central venous catheter (CVC) removals (14/78 (18%) versus 57/160 (36%), p 0.004), and reduced vancomycin level monitoring (16/52 (31%) versus 71/136 (52%), p 0.009) were observed in the QuickFISH group. QuickFISH implementation was predictive of a lower likelihood of antibiotic therapy prescription (OR 0.35, 95%CI 0.20-0.62, p < 0.001). Prior transplant (RR 1.47, 95%CI 1.13-1.92, p 0.004), neutropenia (RR 1.47, 95%CI 1.09-1.99, p 0.012), multiple positive blood cultures (RR 4.23, 95%CI 3.23-5.54, p < 0.001), and CVC (RR 1.60, 95%CI 1.02-2.53, p 0.043) were independent factors for antibiotic duration., Conclusions: QuickFISH implementation plus AS support leads to greater avoidance of vancomycin therapy and improved resource utilization in cancer patients with CoNS blood cultures., (Copyright © 2018 European Society of Clinical Microbiology and Infectious Diseases. Published by Elsevier Ltd. All rights reserved.)

Methicillin-resistant coagulase-negative staphylococci (MRCoNS) have recently emerged as a significant cause of bovine mastitis worldwide. Here we describe the isolation of MRCoNS from cases of bovine mastitis from a single dairy farm in Australia. Fourteen CoNS isolates were identified as MRCoNS on the basis of having an oxacillin MIC of ≥0.5 μg/mL. The isolates were speciated as S. chromogenes (n = 1) S. fleurettii (n = 1), S. haemolyticus (n = 2), S. sciuri (n = 5), S. simulans (n = 1) S. succinus (n = 2) and S. xylosus (n = 2). Five of the isolates (S. fleuretti, S. haemolyticus S. sciuri and two S. succinus) were mecA-positive. We also detected a previously described S. sciuri mecA homolog in four oxacillin-resistant S. sciuri isolates. The remainder of the putative MRCoNS did not contain any mecA-related resistance determinants in their genomes. Comparative genomic analysis of three previously published S. sciuri isolates, from humans, a squirrel and a cereal crop (rice), and a representative isolate from our study demonstrated clustering and a high degree of genetic homogeneity (>95%), suggesting S. sciuri has low host specificity. In conclusion, CoNS, in particular S. sciuri, may act as a reservoir for SCCmec elements that can easily be spread between different host species by direct cross-infection., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Objectives: Heterogeneously resistant vancomycin-intermediate coagulase-negative staphylococci (hVICoNS) are emerging pathogens causing central-line-associated bloodstream infections (CLABSIs) in neonatal intensive care unit (NICU) patients. Given the burden of disease associated with CLABSI and the current lack of therapeutic guidelines, we aimed to compare the effectiveness of linezolid versus vancomycin used as the definitive antibiotic therapy for hVICoNS CLABSI., Methods: We performed a retrospective cohort study of infants with hVICoNS CLABSI from a single NICU between 2009 and 2014, treated with either linezolid or vancomycin as definitive antibiotic therapy. CLABSI duration, early and late recurrence and in-hospital mortality were compared using propensity score-adjusted proportional hazards and logistic regression models., Results: Of 89 infants with hVICoNS CLABSI, 33 (37.1%) treated with linezolid were compared with 56 (62.9%) treated with vancomycin. The median duration of CLABSI was 5 (range 1-12) versus 4 days (range 0-14) ( P  =   0.11), early recurrences were 3.0% versus 7.1% ( P  =   0.42), late recurrences 0% versus 14.3% ( P  =   0.02) and mortality 27.3% versus 28.6% ( P  =   0.90), when treated with linezolid versus vancomycin, respectively. When adjusting using a continuous propensity score, linezolid had an HR of 0.78 (95% CI 0.48-1.27) for CLABSI duration, an OR of 0.23 (95% CI 0.02-2.56) for early recurrence and an OR of 0.9 (95% CI 0.3-2.67) for mortality, relative to vancomycin., Conclusions: There was no statistically significant difference between linezolid and vancomycin when used as definitive treatment for hVICoNS CLABSI in NICU patients, in terms of CLABSI duration, recurrence or all-cause mortality., (© The Author 2017. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

The aim of this study was to investigate the criteria used to distinguish coagulase-negative staphylococci (CoNS) bacteremia from contamination. We evaluated 162 adult patients with CoNS-positive blood cultures (BCs). Of the 162 patients, 35 (21.6%) had at least 2 positive BCs and 127 (78.4%) had a single positive BC. According to the Laboratory-Confirmed Bloodstream Infection (LCBI) criteria, 24 (14.8%) patients with the same species of CoNS had true bacteremia, and 138 (85.2%) patients had contaminants. Despite the detection of the same CoNS species, 9 of the 24 patients had different CoNS genotypes. Using clinical assessments, only 20 patients were diagnosed with true bacteremia, 8 of them had a single positive BC. We concluded that only using the LCBI criteria or clinical evaluations of a patient were not sufficient to distinguish CoNS bacteremia from contamination. Molecular identification should also be performed as a diagnostic laboratory parameter for CoNS bacteremia., (Copyright © 2016 Elsevier Inc. All rights reserved.)

The primary aim of this study was to determine antimicrobial resistance in coagulase-negative staphylococci (CoNS) from healthy adults in the community. Healthy adults (n = 114) were swabbed on six body sites; both armpits, both knee pits and both sides of the groin. Species determination was performed using Matrix Assisted Laser Desorption Ionization - Time of Flight (MALDI-TOF) and susceptibility testing for 11 relevant antimicrobials was performed by the disc diffusion method and minimal inhibitory concentration gradient test. In total, 693 CoNS isolates were identified. Susceptibility testing was done on 386 isolates; one CoNS from each species found on each participant from the different body sites. The prevalence of antimicrobial resistance in the CoNS isolates were; erythromycin (24.6%), fusidic acid (19.9%), tetracycline (11.4%), clindamycin (7.8%), gentamicin (6.2%) and cefoxitin (4.1%). Multidrug resistance was observed in 5.2% of the isolates. Staphylococcus epidermidis and S. hominis were the first and second most prevalent species on all three body sites. We conclude that CoNS isolates from healthy adults in the community have a much lower prevalence of antimicrobial resistance than reported in nosocomial CoNS isolates. Still, we believe that levels of resistance in community CoNS should be monitored as the consumption of antimicrobials in primary care in Norway is increasing., (© 2016 APMIS. Published by John Wiley & Sons Ltd.)

Neonatal septicemia is one of the leading causes of neonatal mortality and morbidity worldwide. Hence, the present study was undertaken to isolate the bacteria causing neonatal sepsis and determine their antibiotic susceptibility pattern. Fifty neonates suspected to have septicemia were screened for 2 months (July and August 2014). Out of 50 specimen, 15 (30%) were blood culture positive. Coagulase-negative staphylococci was the most common isolate (10, 66.6%), with 60% (6 isolates) methicillin resistance. In view of the increasing antibiotic resistance, periodic surveillance should be conducted to control the emergence and spread of antimicrobial resistance.

Staphylococcus chromogenes is one of the main coagulase-negative staphylococci isolated from mastitis of dairy cows. We describe S. chromogenes isolates that can clot plasma. Since the main pathogen causing mastitis is coagulase-positive Staphylococcus aureus, the coagulase-positive phenotype of S. chromogenes described here can easily lead to misidentification., (Copyright © 2016, American Society for Microbiology. All Rights Reserved.)

Coagulase negative staphylococci (CoNS) are nosocomial pathogens that cause indwelling medical device associated infections due to its biofilm forming potential and multiple antibiotic resistance. The current study focused on species identification, antibiotic resistance profile and molecular basis of biofilm formation and attachment of CoNS isolated from clinical samples. Along with this, molecular screening for mecA and newly identified surface colonization protein encoded by sasX gene was also conducted. S. epidermidis (n = 19, 47%) was identified as the most prevalent CoNS species and very interestingly two biofilm forming, mecA positive S. epidermidis isolates were found to carry all the biofilm associated genes screened in this study, which indicates its potential to form the strong biofilm. Another novel observation of the study is the detection of sasX gene in one biofilm positive S. epidermidis isolate. The study also identified one doxycycline resistant mecA positive, multidrug resistant S. haemolyticus isolate. In conclusion, the study signifies the existence of multiple biofilm related genes, multidrug resistance and the presence of sasX gene among clinical isolates of CoNS., (© 2016 APMIS. Published by John Wiley & Sons Ltd.)

We investigated the prevalence of methicillin-resistant coagulase-negative staphylococci (MRCoNS) isolated from hospitalized patients and outpatients (OP). Out of 350 staphylococcal isolates collected from three hospitals, 190 were coagulase-negative staphylococci (CoNS). These isolates were subjected to antimicrobial susceptibility tests, detection of mecA, and pulsed-field gel electrophoresis (PFGE) typing. Among the 190 isolated CoNS, Staphylococcus epidermidis (47.3%) and Staphylococcus haemolyticus (44.2%) were the most prevalent species. Other CoNS species that were isolated were Staphylococcus saprophyticus (2.1%), Staphylococcus warneri (2.1%), Staphylococcus simulans (1.6%), Staphylococcus capitis (1.1%), Staphylococcus schleiferi (1.1%), and Staphylococcus hominis (0.5%). The rate of resistance to methicillin was 60% with 58 (50%) S. epidermidis and 55 (49%) S. haemolyticus. The rate of resistance to 13 antibiotics tested with the lowest and highest to chloramphenicol and penicillin, respectively. High clonal diversity with different PFGE patterns was obtained for methicillin-resistant S. epidermidis and S. haemolyticus by 32 and 31 types, respectively. Our results indicated that the dissemination of MRCoNS is widespread in Tehran. The majority of these isolates showed distinct genotyping patterns. At the same time, the common patterns were found among the MRCoNS obtained from outpatient and inpatient isolates, suggestive of an epidemiological link.

Introduction: Bovine mastitis is a frequent cause of economic loss in dairy herds. Coagulase-negative staphylococci (CoNS) are increasing in importance as causeof bovine intramammary infection (IMI) throughout the world in recent years. CoNShave been isolated from milk samples collected from cows with clinical andsubclinical mastitis in several countries. Identification of mastitis pathogensis important when selection appropriate antimicrobial therapy., Methodology: A total of 93 strains of Staphylococcusspp isolated from bovine clinical andsubclinical mastitis in Argentina during 2010-2013 were identified by Restriction Fragment Length Polymorphism (RFLP)-PCR using the gap gene. The isolates were tested by PCR for the presence of blaZ gene and mecA gene and were tested by disk diffusion for the susceptibilityto penicillin and cefoxitin., Results: The most common CoNS species was S.chromogenes 46.2% (43/93), followed by S. devriesei 11.8% (11/93) and S. haemolyticus 9.7% (9/93). The blaZ gene was detected in 19 (20.4%) but only 16 (17.2%) isolates were resistant to penicillin; the mecA was detected in6 (6.5%) isolates but only 4 (4.3) were resistant to cefoxitin. The 6 mecA-positive isolates showed oxaxillinMICs ≤ 0.5 μg/ml., Discussion: CoNSare important minor mastitis pathogens and can be the cause of substantial economic losses. Despite the low resistance to PEN in Argentina, the presenceof MR isolates found in this study emphasize the importance of identificationof CoNS when an IMI is present because of the potentially risk of lateraltransfer of resistance genes between staphylococcal species.

Periprosthetic joint infections (PJIs) are frequently caused by methicillin-resistant coagulase-negative staphylococci (CoNS). Cultures remain the gold standard but often require a few days. Thus, a rapid test could be interesting to guide antibiotic strategy earlier. The purpose of this study was to evaluate the performances of RT-PCR Xpert® MRSA/SA technique for the detection of methicillin-resistant CoNS (MRCoNS) from deep samples in patients with PJIs. RT-PCR was tested on 72 samples. Sensitivity, specificity, positive predictive value, and negative predictive value of RT-PCR method were 0.36, 0.98, 0.90, and 0.74, respectively. Although RT-PCR may allow early microbial diagnosis of PJI due to Staphylococcus aureus (MSSA and MRSA), the low sensitivity and the high cost of this method to detect MRCoNS could limit its use in this field., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Background: Elevated C-reactive protein (CRP) level is widely used in clinical practice as a marker to distinguish between neonates with or without sepsis. However, some neonates with bacteremia have a CRP level within the normal range and they are not well characterized., Methods: All episodes of neonatal culture-proven bloodstream infections (BSIs) between July 2004 and June 2012 were enrolled. Patients characteristics were compared for three CRP groups (low, ≤ 10 mg/L; intermediate, 11-100 mg/L; and high, > 100 mg/L) using the Chi-square test and one-way ANOVA. The sepsis-attributable mortality rates were compared using logistic regression analyses., Results: Of 986 episodes of neonatal BSI, 247 (25.1 %) had CRP ≤10 mg/L at the onset of clinical sepsis. In the low CRP group, patients had lower gestational age and birth weight, and an earlier occurrence of BSI. Patients with underlying gastrointestinal pathology, renal disorders, cholestasis, and pulmonary hypertension had a non-significant elevated CRP level at the onset of sepsis. In the blood culture of the low CRP group, coagulase-negative staphylococci (CoNS) were relatively more common (55.9 %, p < 0.001) than the other two groups, although one-fourth were infected with gram-negative bacilli (19.0 %), fungi (2.8 %), or polymicrobial pathogens (3.6 %). Of the BSIs with initial low CRP, 29.1 % were treated with inadequate antibiotics, 13.0 % progressed to septic shock, and 5.3 % had infectious complications. The sepsis-attributable mortality rate was lower in the low CRP group (4.9 %) than in the high CRP group (13.6 %)., Conclusions: A considerable proportion of neonatal BSIs had a normal or low initial CRP level (≤10 mg/L), which was more likely to occur in low birth weight or extremely preterm infants, those with earlier onset of sepsis, and those infected with CoNS. Plasma CRP level should not be used to rule out severe culture-proven sepsis or guide the empirical choice of antibiotics.

Sortase A (SrtA) is a cysteine transpeptidase and virulence factor from Staphylococcus aureus (S. aureus) that catalyses the attachment and display of surface proteins on the cell wall, thereby mediating bacterial adhesion to host tissues, host-cell entry and evasion of the immune response. As a result, SrtA has become an important target in the development of therapies for S. aureus infections. In this study, we used the new reference strain S. aureus Newman D2C to investigate the role of SrtA in a murine model of bloodstream infection, when the impact of coagulase and haemolysin is excluded. The results suggested that deletion of SrtA reduced the bacterial burden on the heart, liver and kidneys by blunting the host proinflammatory cytokine response at an early point in infection. Kidneys, but not heart or liver, formed abscesses on the sixth day following non-lethal infection, and this effect was diminished by SrtA mutation. These findings indicate that SrtA is a determining virulence factor in lethality and formation of renal abscesses in mice followed by S. aureus bloodstream infection. We have thus established a convenient in vitro and mouse model for developing SrtA-targeted therapeutic strategies., (© FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

It is uncertain whether an initial inappropriate empirical antibiotic treatment of coagulase-negative staphylococci (CoNS) bacteremia adversely affects the outcome. A retrospective cohort study of CoNS bacteremia was performed at the Dongguk University Ilsan Hospital during a 3-year period. During the study period, 109 patients with CoNS bacteremia were enrolled. The median age of the patients was 72 years and most (96%, 105/109) had one or more comorbid diseases. Among the participants, 29% (32/109) received an appropriate empirical antimicrobial therapy. The 30-day mortality was 24% (26/109) and CoNS bacteremia-related mortality was 14% (15/109). There was no difference in the CoNS bacteremia-related mortality between the group with an inappropriate empirical treatment (13%, 10/77) and that with an appropriate treatment (16%, 5/32) (p = 0.46). In the multivariate analysis using the Cox regression analysis method, Pitt bacteremia scores [hazard ratio (HR) 1.48; 95% confidence interval (CI) 1.09-2.01; p = 0.01] and retention of eradicable focus (HR 5.0; 95% CI 1.39-17.9; p = 0.01) were found to be associated with CoNS bacteremia-related mortality. The results suggest that inappropriate empirical therapy might not necessarily be associated with the 30-day mortality or CoNS bacteremia-related mortality. Conversely, Pitt bacteremia scores and retention of eradicable focus were associated with poor outcomes.

Objectives: It is unknown if vancomycin minimal inhibitory concentrations (MICs) have increased in coagulase-negative staphylococci (CoNS) or whether vancomycin remains appropriate empiric therapy., Methods: We performed a retrospective study at a single tertiary care center over 8 years. Adult inpatients with ≥2 positive blood cultures for CoNS within a 48-h period were eligible. Susceptibilities were performed by automated broth based-microdilution. Changes in antimicrobial susceptibility were analyzed using logistic regression. The clinical characteristics and outcomes of patients with bloodstream infections (BSI) were compared by MIC., Results: Of 308 episodes of possible CoNS bacteremia, the vancomycin MIC was ≤1 μg/mL in 80 (26%) isolates, 2 μg/mL in 223 (72.4%) isolates and 4 μg/mL in 5 (1.6%) isolates. No isolates were resistant. We observed an 11-fold increased chance of having an isolate with a vancomycin MIC ≤1 μg/mL in 2009-2011 compared with 2004-2008 (OR 10.8, 95% CI 6.0-19.5, p < 0.05). In 152 patients with BSI, the median days of bacteremia, hospital mortality and readmissions at 30 days were similar in BSI caused by isolates with high vancomycin MICs (2-4 μg/mL) and low vancomycin MICs (≤1 μg/mL)., Conclusions: We conclude vancomycin is still appropriate empiric therapy for CoNS BSIs. CoNS vancomycin MICs decreased over the study period despite widespread use of vancomycin., (Copyright © 2015 The British Infection Association. Published by Elsevier Ltd. All rights reserved.)

The use of matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) for staphylococcal identification is now considered routine in laboratories compared with the conventional phenotypical methods previously used. We verified its microbiological relevance for identifying the main species of coagulase-negative staphylococci (CoNS) by randomly selecting 50 isolates. From 1 January 2007 to 31 August 2008, 12,479 staphylococci were isolated with phenotypic methods, of which 4,594 were identified as Staphylococcus aureus and 7,885 were coagulase negative staphylococci. Using MALDI-TOF MS from 1 January 2011 to 31 August 2012, 14,913 staphylococci were identified, with 5,066 as S. aureus and 9,847 as CoNS. MALDI-TOF MS allowed the identification of approximately 85% of the CoNS strains, whereas only 14% of the CoNS strains were identified to the species level with phenotypic methods because they were often considered contaminants. Furthermore, the use of MALDI-TOF MS revealed the occurrence of recently characterized Staphylococcus species, such as S. pettenkoferi, S. condimenti, and S. piscifermentans. Microbiological relevance analysis further revealed that some species displayed a high rate of microbiological significance, i.e., 40% of the S. lugdunensis strains included in the analysis were associated with infection risk. This retrospective microbiological study confirms the role of MALDI-TOF MS in clinical settings for the identification of staphylococci with clinical consequences. The species distribution reveals the occurrence of the recently identified species S. pettenkoferi and putative virulent species, including S. lugdunensis., (Copyright © 2015, American Society for Microbiology. All Rights Reserved.)

Coagulase-negative staphylococci (CNS) cause the majority of post-cataract endophthalmitis, which can lead to anatomical and/or functional loss of the eye. This study reports the antibiotic susceptibilities of CNS isolates associated with acute post-cataract endophthalmitis cases and correlates antibiotic resistance with severity and outcome of infection in these patients. Clinical data (initial ocular examination, final prognosis, antibiotic treatment) and the antibiotic susceptibilities of the isolated CNS strains were obtained from 68 patients with post-surgical endophthalmitis recruited during a 7-year period by the FRench Institutional ENDophthalmitis Study (FRIENDS) group. The CNS strains displayed 100% susceptibility to vancomycin, 70% to fluoroquinolones, 83% to fosfomycin, 46% to imipenem and 18% to piperacillin. The most effective antibiotic combinations were fosfomycin plus a fluoroquinolone and imipenem plus a fluoroquinolone, which were considered adequate in 80% and 58% of patients, respectively. Methicillin resistance was significantly associated with older age (p 0.001), diabetes mellitus (p 0.004), absence of fundus visibility (p 0.06), and poor visual prognosis (p 0.03). Resistance to fluoroquinolones was significantly associated with absence of fundus visibility (p 0.05) and diabetes mellitus (p 0.02). This large prospective study demonstrates that methicillin resistance and, to a lesser extent, fluoroquinolone resistance in CNS strains causing postoperative endophthalmitis are both prevalent in France and associated with a poorer visual prognosis. These results emphasize the need for an effective surveillance of this antibiotic resistance and the development of new diagnostic tools for rapid detection for early optimization of antibiotic therapy in endophthalmitis patients., (Copyright © 2015 European Society of Clinical Microbiology and Infectious Diseases. Published by Elsevier Ltd. All rights reserved.)

This study describes coagulase-negative staphylococcal (CoNS) infective endocarditis (IE) epidemiology at our institution, the antibiotic susceptibility profile, and the influence of vancomycin minimum inhibitory concentration (MIC) on patient outcomes. One hundred and three adults with definite IE admitted to an 850-bed tertiary care hospital in Barcelona from 1995-2008 were prospectively included in the cohort. We observed that CoNS IE was an important cause of community-acquired and healthcare-associated IE; one-third of patients involved native valves. Staphylococcus epidermidis was the most frequent species, methicillin-resistant in 52% of patients. CoNS frozen isolates were available in 88 patients. Vancomycin MICs of 2.0 μg/mL were common; almost all cases were found among S. epidermidis isolates and did not increase over time. Eighty-five patients were treated either with cloxacillin or vancomycin: 38 patients (Group 1) were treated with cloxacillin, and 47 received vancomycin; of these 47, 27 had CoNS isolates with a vancomycin MIC <2.0 μg/mL (Group 2), 20 had isolates with a vancomycin MIC ≥ 2.0 μg/mL (Group 3). One-year mortality was 21%, 48%, and 65% in Groups 1, 2, and 3, respectively (P = 0.003). After adjusting for confounders and taking Group 2 as a reference, methicillin-susceptibility was associated with lower 1-year mortality (OR 0.12, 95% CI 0.02-0.55), and vancomycin MIC ≥ 2.0 μg/mL showed a trend to higher 1-year mortality (OR 3.7, 95% CI 0.9-15.2; P=0.069). Other independent variables associated with 1-year mortality were heart failure (OR 6.2, 95% CI 1.5-25.2) and pacemaker lead IE (OR 0.1, 95%CI 0.02-0.51). In conclusion, methicillin-resistant S.epidermidis was the leading cause of CoNS IE, and patients receiving vancomycin had higher mortality rates than those receiving cloxacillin; mortality was higher among patients having isolates with vancomycin MICs ≥ 2.0 μg/mL.

Objectives: Linezolid has been reported to remain active against 98% of staphylococci with resistance identified in 0.05% of Staphylococcus aureus and 1.4% of CoNS. The objective of this study was to characterize the linezolid-resistance mechanisms in the linezolid-resistant CoNS strains isolated in Japan., Methods: Staphylococcus capitis strains exhibiting linezolid MICs >8 mg/L isolated from inpatients between 2012 and 2014 were screened for cfr and mutations in 23S rRNA, L3 and L4 by PCR/sequencing. Isolates were also examined for mutations in the rlmN gene., Results: S. capitis had six 23S rRNA alleles. Five S. capitis isolates displayed linezolid MICs of 8, 16 and 32 mg/L. G2576U mutations were detected in three, four or five copies of 23S rRNA in all isolates. In two isolates exhibiting the highest linezolid MIC (32 mg/L) there was a large deletion in a single copy of 23S rRNA. Repeated 10 bp sequences were found in both 16S and 23S rRNAs, suggesting deletion by recombination between the repeats. One isolate had the mutation Ala-142→Thr in the ribosomal protein L3. All linezolid-resistant isolates also demonstrated mutations in the gene encoding RlmN methyltransferase, leading to Thr-62→Met and Gly-148→Ser., Conclusions: Multiple mechanisms appeared to be responsible for the elevated linezolid resistance in S. capitis isolates: a G2576U mutation in different numbers of copies of 23S rRNA, loss of a single copy of 23S rRNA and a mutation in the ribosomal protein L3, suggesting the accumulation of independent mutational events., (© The Author 2014. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.)

Introduction: Healthcare waste (HCW) might potentially harbor infective viable microorganisms in sanitary landfills. We investigated the antimicrobial susceptibility patterns and the occurrence of the mecA gene in coagulase-negative Staphylococcus strains (CoNS) recovered from the leachate of the HCW in an untreated sanitary landfill., Methodology: Bacterial identification was performed by physiological and molecular approaches, and minimum inhibitory concentrations (MICs) of antimicrobial drugs were determined by the agar dilution method according to CLSI guidelines. All oxacillin-resistant bacteria were screened for the mecA gene., Results: Out of 73 CoNS, seven different species were identified by 16S rDNA sequencing: Staphylococcus felis (64.4%; n = 47), Staphylococcus sciuri (26.0%; n = 19), Staphylococcus epidermidis (2.7%; n = 2), Staphylococcus warneri (2.7%; n = 2), Staphylococcus lentus (1.4%; n = 1), Staphylococcus saprophyticus (1.4%; n = 1), and Staphylococcus haemolyticus (1.4%; n = 1). Penicillin was the least effective antimicrobial (60.3% of resistance; n = 44) followed by erythromycin (39.8%; n = 29), azithromycin (28.8%; n = 21), and oxacillin (16.5%; n = 12). The most effective drug was vancomycin, for which no resistance was observed, followed by gentamicin and levofloxacin, for which only intermediate resistance was observed (22%, n = 16 and 1.4%, n = 1, respectively). Among the oxacillin-resistant strains, the mecA gene was detected in two isolates., Conclusions: Considering the high antimicrobial resistance observed, our results raise concerns about the survival of putative bacterial pathogens carrying important resistance markers in HCW and their environmental spread through untreated residues discharged in sanitary landfills.

Within ecosystems that are poor in carbohydrates, alternative substrates such as arginine may be of importance to coagulase-negative staphylococci (CNS). However, the versatility of arginine conversion in CNS remains largely uncharted. Therefore, a set of 86 strains belonging to 17 CNS species was screened for arginine deiminase (ADI), arginase, and nitric oxide synthase (NOS) activities, in view of their ecological relevance. In fermented meats, for instance, ADI could improve bacterial competitiveness, whereas NOS may serve as an alternative nitrosomyoglobin generator to nitrate and nitrite curing. About 80% of the strains were able to convert arginine, but considerable inter- and intraspecies heterogeneity regarding the extent and mechanism of conversion was found. Overall, ADI was the most commonly employed pathway, resulting in mixtures of ornithine and small amounts of citrulline. Under aerobic conditions, which are more relevant for skin-associated CNS communities, several strains shifted toward arginase activity, leading to the production of ornithine and urea. The obtained data indeed suggest that arginase occurs relatively more in CNS isolates from a dairy environment, whereas ADI seems to be more abundant in strains from a fermented meat background. With some exceptions, a reasonable match between phenotypic ADI and arginase activity and the presence of the encoding genes (arcA and arg) was found. With respect to the NOS pathway, however, only one strain (Staphylococcus haemolyticus G110) displayed phenotypic NOS-like activity under aerobic conditions, despite a wide prevalence of the NOS-encoding gene (nos) among CNS. Hence, the group of CNS displays a strain- and condition-dependent toolbox of arginine-converting mechanisms with potential implications for competitiveness and functionality., (Copyright © 2014, American Society for Microbiology. All Rights Reserved.)

To characterize 46 methicillin-resistant coagulase-negative staphylococci from Brazilian neonates, we investigated their SCCmec type, susceptibility and clonality. Staphylococcus epidermidis and Staphylococcus haemolyticus were the prevalent species. SCCmec types III or IV were detected in 53.3% S. epidermidis, whereas 63.6% S. haemolyticus were nontypeable. Despite the diversity, specific clones carried specific SCCmec elements, highlighting that effective typing can help in epidemiological analysis.

The accurate performance of the Vitek 2 GP67 card for detecting methicillin-resistant coagulase-negative staphylococci (CoNS) is not known. We prospectively determined the ability of the Vitek 2 GP67 card to accurately detect methicillin-resistant CoNS, with mecA PCR results used as the gold standard for a 4-month period in 2012. Included in the study were 240 consecutively collected nonduplicate CoNS isolates. Cefoxitin susceptibility by disk diffusion testing was determined for all isolates. We found that the three tested systems, Vitek 2 oxacillin and cefoxitin testing and cefoxitin disk susceptibility testing, lacked specificity and, in some cases, sensitivity for detecting methicillin resistance. The Vitek 2 oxacillin and cefoxitin tests had very major error rates of 4% and 8%, respectively, and major error rates of 38% and 26%, respectively. Disk cefoxitin testing gave the best performance, with very major and major error rates of 2% and 24%, respectively. The test performances were species dependent, with the greatest errors found for Staphylococcus saprophyticus. While the 2014 CLSI guidelines recommend reporting isolates that test resistant by the oxacillin MIC or cefoxitin disk test as oxacillin resistant, following such guidelines produces erroneous results, depending on the test method and bacterial species tested. Vitek 2 cefoxitin testing is not an adequate substitute for cefoxitin disk testing. For critical-source isolates, mecA PCR, rather than Vitek 2 or cefoxitin disk testing, is required for optimal antimicrobial therapy., (Copyright © 2014, American Society for Microbiology. All Rights Reserved.)

Rapid diagnostic testing with matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) decreases the time to organism identification by 24 to 36 h compared to the amount of time required by conventional methods. However, there are limited data evaluating the impact of MALDI-TOF with real-time antimicrobial stewardship team (AST) review and intervention on antimicrobial prescribing and outcomes for patients with bacteremia and blood cultures contaminated with coagulase-negative Staphylococcus (CoNS). A quasiexperimental study was conducted to analyze the impact of rapid diagnostic testing with MALDI-TOF plus AST review and intervention for adult hospitalized patients with blood cultures positive for CoNS. Antibiotic prescribing patterns and clinical outcomes were compared before and after implementation of MALDI-TOF with AST intervention for patients with CoNS bacteremia and CoNS contamination. A total of 324 patients with a positive CoNS blood culture were included; 246 were deemed to have contaminated cultures (117 in the preintervention group and 129 in AST the intervention group), and 78 patients had bacteremia (46 in the preintervention group and 32 in the AST intervention group). No differences in demographics were seen between the groups, and similar rates of contamination occurred between the preintervention and AST intervention groups (64.3% versus 72.6%, P = 0.173). Patients with bacteremia were initiated on optimal therapy sooner in the AST intervention group (58.7 versus 34.4 h, P = 0.030), which was associated with a similarly decreased mortality (21.7% versus 3.1%, P = 0.023). Patients with CoNS-contaminated cultures had similar rates of mortality, lengths of hospitalization, recurrent bloodstream infections, and 30-day hospital readmissions, but the AST intervention group had a decreased duration of unnecessary antibiotic therapy (1.31 versus 3.89 days, P = 0.032) and a decreased number of vancomycin trough assays performed (0.88 versus 1.95, P < 0.001). In patients with CoNS bacteremia, rapid pathogen identification integrated with real-time stewardship interventions improved timely organism identification and initiation of antibiotic therapy. Patients in the AST group with blood cultures contaminated with CoNS had decreased inappropriate antimicrobial prescribing and decreased unnecessary serum vancomycin trough assays., (Copyright © 2014, American Society for Microbiology. All Rights Reserved.)

Staphylococci are one of the most prevalent microorganisms in bovine mastitis. Staphylococcus spp. are widespread in the environment, and can infect animals and humans as opportunistic pathogens. The objective of this study was to determine the frequency of methicillin-resistance (MR) among coagulase-negative staphylococci (CoNS) previously obtained from milk of mastitic cows in Brazil and to characterize the antimicrobial resistance phenotype/genotype and the SCCmec type of MRCoNS isolates. Identification of MRCoNS was based on both biochemical and molecular methods. Susceptibility testing for eleven antimicrobials was performed by disk-diffusion agar. Antimicrobial resistance genes and SCCmec were investigated by specific PCRs. Twenty-six MRCoNS were detected (20 % of total CoNS), obtained from 24 animals, and were identified as follows: S. epidermidis (7 isolates), S. chromogenes (7), S. warneri (6), S. hyicus (5) and S. simulans (1). All MRCoNS isolates carried mecA while the mecC gene was not detected in any CoNS. The SCCmec IVa was demonstrated in nine MRCoNS, while the remaining 17 isolates harbored non-typeable SCCmec cassettes. In addition to oxacillin and cefoxitin resistance, MRCoNS showed resistance to tetracycline (n = 7), streptomycin (n = 6), tobramycin (n = 6), and gentamicin (n = 4), and harbored the genes tet(K) (n = 7), str (n = 3), ant(4') (n = 6) and aac(6')-aph(2″) (n = 4), respectively. In addition, seven strains showed intermediate resistance to clindamycin and two to streptomycin, of which two harboured the lnu(B) and lsa(E) genes and two the aad(E) gene, respectively. One isolate presented intermediate erythromycin and clindamycin resistance and harbored an erm(C) gene with an uncommon 89-bp deletion rendering a premature stop codon. MRCoNS can be implicated in mastitis of cows and they constitute a reservoir of resistance genes that can be transferred to other pathogenic bacteria.

The present study focussed on the analysis of the genetic environment of the multi-resistance gene cfr detected among 21, mostly methicillin-resistant, coagulase-negative Staphylococcus (CoNS) isolates obtained from chickens, ducks and pigs in China. It included sequencing of the regions up- and downstream of the cfr gene on various plasmid types in 13 isolates, such as pSS-02 and pSS-02-like (n=7), pSS-03-like (n=1), pJP1-like (n=3), pSS-04 (n=1) and pJP2 (n=1). This analysis revealed that insertion sequences (IS21-558, IS256, IS257, or IS1216E) and other resistance genes (aacA-aphD and aadD for aminoglycoside resistance, ble for bleomycin resistance, fosD for fosfomycin resistance, erm(B) and erm(C) for macrolide-lincosamide-streptogramin B resistance, or fexA for phenicol resistance) coexisted on the respective plasmids. In the chromosomal copies of cfr identified in eight S. lentus isolates, the cfr gene was found to be bracketed by insertion sequences, such as IS256 or ISEnfa5. Stability tests confirmed that all chromosomal cfr-containing regions could be looped out via IS-mediated recombination. The observations made in this study extend the rather rudimentary knowledge about the genetic environment of cfr in staphylococci from chickens and ducks and confirmed that insertion sequences play an important role in the dissemination of cfr, not only among different types of plasmids, but also for the integration in the chromosomal DNA., (Crown Copyright © 2013. Published by Elsevier GmbH. All rights reserved.)

Silver nanoparticles form promising template for designing antimicrobial agents against drug resistant pathogenic microorganisms. Thus, the development of a reliable green approach for the synthesis of nanoparticles is an important aspect of current nanotechnology research. In the present investigation, silver nanoparticles synthesized by a soil Bacillus sp. were characterized using UV-vis spectroscopy, FTIR, SEM, and EDS. The antibacterial potential of biosynthesized silver nanoparticles, standard antibiotics, and their conjugates were evaluated against multidrug-resistant biofilm-forming coagulase-negative S. epidermidis strains, S. aureus, Salmonella Typhi, Salmonella Paratyphi, and V. cholerae. Interestingly, silver nanoparticles (AgNPs) showed remarkable antibacterial activity against all the test strains with the highest activity against S. epidermidis strains 145 and 152. In addition, the highest synergistic effect of AgNPs was observed with chloramphenicol against Salmonella typhi. The results of the study clearly indicate the promising biomedical applications of biosynthesized AgNPs.

Background: Early Onset Sepsis (EOS) is associated with increased major morbidity and mortality rates among very low birth weight (VLBW) infants. The epidemiology is changing in response to evolving medical practice. The objective of the study was to evaluate EOS epidemiology, risk factors, mortality and major morbidity rates among VLBW infants within a European cohort., Methods: Data from VLBW infants born from 2006 through 2009 was collected by neonatal units participating in the EuroNeoNet initiative. Univariate and multivariate analyses were performed to assess the independent association of EOS with VLBW infant's perinatal characteristics, morbidity and mortality rates., Results: The cohort included 14,719 infants, 391 developed EOS (2.7%). The most common pathogen responsible for EOS was Gram-positive bacteria (53.9%). Coagulase-negative staphylococci (CoNS) were isolated in 22.5% of episodes. Antenatal steroids exposure, single gestation, very low gestational age and birth weight, low 5 minute Apgar score and delivery room resuscitation were independently associated with EOS. EOS was also associated with a longer hospital stay, increased risk of mortality [adjusted odd ratio (aOR): 2.4; 95% Confidence Interval (CI): 1.9-3.1], respiratory distress syndrome (OR: 1.4; 95% CI: 1.1-1.9), severe intraventricular haemorrhage (aOR: 2.1; 95%CI: 1.6-2.8) and severe retinopathy of prematurity (aOR: 5; 95% CI: 1.9-13.3). Morbidity and mortality rates of infants with EOS caused by CoNS were similar to those of infants with EOS caused by other pathogens., Conclusions: VLBW infants with EOS are at an increased risk of mortality and major morbidities. CoNS was a significant cause of sepsis, infants with CoNS were at a similarly high risk of complication of prematurity and mortality as those with EOS caused by other organisms.

The occurrence, resistance phenotype and molecular mechanisms of resistance of methicillin-resistant staphylococci from groin swabs of 109 clinically healthy dogs in Nsukka, Nigeria were investigated. The groin swab samples were cultured on mannitol salt agar supplemented with 10 μg of cloxacillin. Sixteen methicillin-resistant coagulase negative staphylococci (MRCoNS), all harbouring the mecA gene were isolated from 14 (12.8%) of the 109 dogs studied. The MRCoNS isolated were: S. sciuri subspecies rodentium, S. lentus, S. haemolyticus, and S. simulans with S. sciuri subspecies rodentium (62.5%) being the predominant species. Thirteen (81.3%) of the MRCoNS were resistant to tetracycline while 12 (75%) and 10 (62.5%) were resistant to kanamycin and trimthoprim-sulphamethoxazole respectively. None of the isolates was resistant to fusidic acid, linezolid and vancomycin. Thirteen (81.3%) of the MRCoNS were multi-drug resistance (MDR). Other antimicrobial genes detected were: blaZ, tet(K), tet(M), tet(L), erm(B), lnu(A), aacA-aphD, aphA3, str, dfr(G), cat pC221 , and cat pC223 . Methicillin-resistant staphylococci are common colonizers of healthy dogs in Nigeria with a major species detected being S. sciuri subsp. rodentium.

Temu kunci (Kaempferia pandurata (Roxb.)) has a number of benefits and one of these is antibacterial. The rhizome is said to have antibacterial activity against Streptococcus mutans, Lactocillus sp. and Candida albicans. The aim of the study is to test the antibacterial activity of Kaempferia pandurata (Roxb.) rhizome ethanol extract on methicillin-resistant Staphylococcus aureus (MRSA), methicillin-resistant coagulase negative Staphylococci (MRCNS), methicillin-sensitive Staphylococcus aureus (MSSA), Bacillus subtilis and Salmonella typhi. Antimicrobial activity of the extract was assayed by the microdilution method using Mueller Hinton Broth with sterilized 96 round-bottomed microwells to determine the Minimum Inhibitory Concentration (MIC) as well as to determine the time-kill activity. The MIC of the extract was 16 ppm for both Bacillus subtilis and MRSA; 8 ppm for both MSSA and Salmonella typhi and 4 ppm for MRCNS. Ethanol extract of Kaempferia pandurata (Roxb.) showed antibacterial activity against all the tested bacteria and was the most potent against MRCNS, with MIC 4 ppm. The killing profile test of the extract displayed bactericidal activity at 8-16 ppm against MRSA, MSSA, Bacillus subtilis and Salmonella typhi and bacteriostatic activity at 4 ppm towards MRCNS.

Coagulase-negative staphylococci (CoNS) are the leading cause of late-onset sepsis (LOS) in neonates. Increasing resistance of CoNS to beta-lactams and aminoglycosides has led to widespread use of vancomycin, which in turn may lead to resistance to vancomycin. Thus, combination therapy of LOS has been advocated. We aimed to determine the interaction of oxacillin and gentamicin against CoNS. In 2005, 34 isolates of oxacillin- and gentamicin-resistant CoNS were obtained from blood samples of neonates with LOS. Combination effect was tested using the checkerboard method, E-test with the other antibiotic incorporated in the medium (E-test-1) and two E-test strips placed in a cross-formation (E-test-2). Of 34 isolates 61.8%, 53% and 73.5% revealed synergy or an additive effect when tested by the checkerboard method, E-test-1 and E-test-2, respectively. Results of all three tests were concordant for six (17.6%) isolates, four showing synergy, and two indifference. Our in vitro results support that combination therapy with penicillinase-resistant penicillin and aminoglycoside can be an alternative to vancomycin., (© 2013 APMIS. Published by John Wiley & Sons Ltd.)

Evaluating the clinical significance of blood cultures positive for coagulase-negative staphylococci (CoNS) is of critical importance since these microorganisms represent both the first contaminants of blood cultures and one of the leading causes of bloodstream infection (BSI). This prospective 2-centre study aimed to compare a previously reported algorithm to a clinical algorithm based on our experience. We identified 84 patients with CoNS-positive blood cultures. Twenty-seven (32%) were considered to have BSI according to our study algorithm. Thirty-seven (44%) patients were considered to have CoNS BSI according to the previously reported algorithm. The 2 algorithms isolated patients with similar rates of recurrences and hospital mortality. Our algorithm seemed to result in less diagnoses of CoNS BSI without harmful consequences compared to the previously reported algorithm. The impact on patient outcome and the inappropriate use of antibiotics deserves further investigation.

Background: Exit site infections (ESIs) have been previously associated with the development of peritonitis; however, the evidence to support this association is limited. We conducted a time-matched, case-control study to determine the association between ESIs and subsequent peritonitis., Methods: The cohort comprised 962 incident adult peritoneal dialysis (PD) patients from January 2000 to December 2009. Patients with an ESI were matched to those with no ESI based on the duration of PD. The subsequent risk of peritonitis was determined using Cox models and conditional logistic regression., Results: During the study period, there were a total of 1002 ESI and 1228 peritonitis episodes among 962 individuals. The time to subsequent peritonitis was shorter in individuals who had at least one ESI [hazard ratio (HR) 1.59; 95% confidence interval (CI) 1.22-2.07, P<0.001]. The risk of peritonitis post-ESI was increased for all Gram-positive infections [adjusted hazard ratio (aHR) 1.75; 95% CI 1.25-2.43], and for the subtypes of coagulase-negative Staphylococcus (CNS) and S. aureus, but not for Gram-negative or culture-negative infections. These findings were similar when examining the odds of subsequent peritonitis within prespecified time intervals of the ESI through conditional logistic regression., Conclusions: The risk of peritonitis after ESI is increased, particularly with S. aureus and CNS, despite appropriate antibiotic treatment of the ESI.

Introduction: Coagulase-negative staphylococci (CoNS) are a group of micro-organisms that are increasingly implicated as a cause of significant infection and the leading cause of bloodstream infection (BSI). One important predictor of true BSI is the isolation of CoNS from multiple blood cultures, presuming that the isolates represent the same species. Thus the objective of this study was to determine the significance of repeated CoNS isolated from blood cultures., Methodology: This was a prospective laboratory study which was initiated in June 2007 and lasted until July 2008. CoNS isolates were obtained from patients who had two positive blood cultures within a 14-day interval. CoNS were identified to the species level using an API-Staph, and antibiotics susceptibility testing was performed according to Clinical and Laboratory Standards Institute specifications. Strain relatedness was confirmed using pulsed-field gel electrophoresis., Results: During the study period, 202 CoNS-positive samples were isolated from 101 patients. The most common species isolated was Staphylococcus epidermidis (59.0%), and 83.2% of the patients isolated the same species of CoNS from repeated blood cultures. Among the isolates of the same species, only 40.7% had the same antibiogram. CoNS with the same species and antibiogram had 93.3% probability of belonging to the same strain. Most (65.5%) of the patients were treated with antibiotics, primarily from the glycopeptides group., Conclusion: Speciation and antibiogram of CoNS from repeated blood cultures are adequate in determining the significance of repeated CoNS isolated from blood cultures.