Environmental surveillance identifies multiple introductions of MRSA CC398 in an Equine Veterinary Hospital in the UK, 2011-2016

Methicillin-resistant Staphylococcus spp. investigation in hospitalized horses and contacting personnel in a teaching veterinary hospital

Staphylococci are well-known opportunistic pathogens associated with suppurative diseases in humans and animals. Antimicrobial resistance is an emergent threat to humans and animals worldwide. This study investigated the prevalence of methicillin-resistant Staphylococcus spp. (MRS) in hospitalized horses and contacting personnel (veterinarians and staff), and assessed possible interspecies transmission in a teaching veterinary hospital. Nasal swabs from horses (n = 131) and humans (n = 35) were collected. The microorganisms were identified by traditional biochemical tests and genotypic methods, i.e., PCR, internal transcript spacer PCR (ITS-PCR), and gene sequencing. Staphylococcal species were isolated in 18% (23/131) of the horses, of which 8% (11/131) were S. hyicus, 4 % (5/131) were S. aureus, 4% (5/131) were S. pseudintermedius, and 2% (2/131) were S. schleiferi subsp. coagulans. The mecA gene was detected in an S. pseudintermedius isolate. Staphylococcus spp. was isolated in 40% (14/35) of the human samples, all of which were S. aureus. In four samples of S. aureus, the clonal profile ST398 was identified; among them, a clonal similarity of 98.1% was observed between a horse and a contacting human. This finding supports the need for biosecurity measures to avoid the spread of multidrug-resistant staphylococci in humans and horses.

Rapid typing of Klebsiella pneumoniae and Pseudomonas aeruginosa by Fourier-transform Infrared spectroscopy informs infection control in veterinary settings

Introduction

The emergence of multi-drug resistant (MDR) pathogens linked to healthcare-associated infections (HCAIs) is an increasing concern in modern veterinary practice. Thus, rapid bacterial typing for real-time tracking of MDR hospital dissemination is still much needed to inform best infection control practices in a clinically relevant timeframe. To this end, the IR Biotyper using Fourier-Transform InfraRed (FTIR) spectroscopy has the potential to provide fast cluster analysis of potentially related organisms with substantial cost and turnaround time benefits.

Materials and methods

A collection of MDR bacterial isolates (n = 199, comprising 92 Klebsiella pneumoniae and 107 Pseudomonas aeruginosa) obtained from companion animal (i.e., dogs, cats and horses) clinical investigations, faecal and environmental screening from four veterinary facilities between 2012 and 2019 was analysed retrospectively by FTIR spectroscopy. Its performance was compared against MLST extracted from whole genomes of a subset of clustering isolates (proportionally to cluster size) for investigation of potential nosocomial transmission between patients and the surrounding hospital environments.

Results

Concordance between the FTIR and MLST types was overall high for K. pneumoniae (Adjusted Rand Index [ARI] of 0.958) and poor for P. aeruginosa (ARI of 0.313). FTIR K. pneumoniae clusters (n = 7) accurately segregated into their respective veterinary facility with evidence of intra-hospital spread of K. pneumoniae between patients and environmental surfaces. Notably, K. pneumoniae ST147 intensely circulated at one Small Animal Hospital ICU. Conversely, Pseudomonas aeruginosa FTIR clusters (n = 18) commonly contained isolates of diversified hospital source and heterogeneous genetic background (as also genetically related isolates spread across different clusters); nonetheless, dissemination of some clones, such as P. aeruginosa ST2644 in the equine hospital, was apparent. Importantly, FTIR clustering of clinical, colonisation and/or environmental isolates sharing genomically similar backgrounds was seen for both MDR organisms, highlighting likely cross-contamination events that led to clonal dissemination within settings.

Conclusion

FTIR spectroscopy has high discriminatory power for hospital epidemiological surveillance of veterinary K. pneumoniae and could provide sufficient information to support early detection of clonal dissemination, facilitating implementation of appropriate infection control measures. Further work and careful optimisation need to be carried out to improve its performance for typing of P. aeruginosa veterinary isolates.

Resistome-based surveillance identifies ESKAPE pathogens as the predominant gram-negative organisms circulating in veterinary hospitals

Introduction

Healthcare-associated infections (HCAIs) associated with extended-spectrum cephalosporin-resistant gram-negative (ESC-R GN) bacteria are an emerging concern in veterinary hospitals, especially in companion animal intensive care units (ICUs).

Methods

To understand the molecular epidemiology of ESC-R GN isolates in two veterinary hospitals (equine and small animal), a 6-month pilot study was performed during which fecal and environmental samples were obtained twice from selected patients, upon ICU admission and after 48 h of hospitalization. In total, 295 ESC-R GNs were analyzed using the Acuitas Resistome® Test (OpGen, Maryland, US), a PCR-based assay screening for 50 antimicrobial resistance gene families encoding for production of extended-spectrum beta-lactamase (ESBLs), TEM/SHV/OXA or AmpC beta-lactamases and carbapenemases. Combining organism identification and antimicrobial susceptibility data to genotyping results, unique "Acuitas profiles" were generated that can be used for fast typing the isolates and tracking transmission events.

Results

ESKAPE GN pathogens were the most prevalent ESC-R GN isolates circulating in both the small animal and equine hospitals, consisting of Enterobacter cloacae complex (21.7%), Pseudomonas aeruginosa (20%), Klebsiella pneumoniae (15.9%), and Acinetobacter baumannii complex (13.6%) followed by Escherichia coli (12.2%), most harboring a combination of genes encoding for beta-lactamases and ESBLs. Some ESKAPE genotypes showed likely intra-hospital transmission, including E. cloacae (two genotypes, one carrying SHV4, SHV5, and TEM7 and the other TEM1, TEM3, and TEM7 enzymes) in the equine and K. pneumoniae (SHV1, SHV5, and DHA1-positive) in the small animal ICUs, respectively. Furthermore, P. aeruginosa (carrying OXA-50), A. baumannii complex (OXA-51), and E. coli (CTX-M-1) genotypes were isolated across both hospitals, suggesting possible transfer mediated via movement of staff and students. Importantly, isolates carrying transmissible resistance to last-resort antimicrobials (i.e. carbapenems) were identified within the hospital environments, consisting of three environmental Acinetobacter spp. harboring blaOXA - 23 and one clinical E. coli with blaOXA - 48.

Conclusion

We describe the widespread occurrence of ESKAPE gram-negative organisms in veterinary ICU patients and hospital environments. Findings from this project provide baseline data on the epidemiology of ESKAPE pathogens in veterinary settings, which can inform infection control policies to aid in patient management and prevent transmission of nosocomial infections associated with these pathogens.

The European Union Summary Report on Antimicrobial Resistance in zoonotic and indicator bacteria from humans, animals and food in 2020/2021

Antimicrobial resistance (AMR) data on zoonotic and indicator bacteria from humans, animals and food are collected annually by the EU Member States (MSs) and reporting countries, jointly analysed by EFSA and ECDC and presented in a yearly EU Summary Report. This report provides an overview of the main findings of the 2020-2021 harmonised AMR monitoring in Salmonella spp., Campylobacter jejuni and C. coli in humans and food-producing animals (broilers, laying hens and turkeys, fattening pigs and bovines under 1 year of age) and relevant meat thereof. For animals and meat thereof, indicator E. coli data on the occurrence of AMR and presumptive Extended spectrum β-lactamases (ESBL)-/AmpC β-lactamases (AmpC)-/carbapenemases (CP)-producers, as well as the occurrence of methicillin-resistant Staphylococcus aureus are also analysed. In 2021, MSs submitted for the first time AMR data on E. coli isolates from meat sampled at border control posts. Where available, monitoring data from humans, food-producing animals and meat thereof were combined and compared at the EU level, with emphasis on multidrug resistance, complete susceptibility and combined resistance patterns to selected and critically important antimicrobials, as well as Salmonella and E. coli isolates exhibiting ESBL-/AmpC-/carbapenemase phenotypes. Resistance was frequently found to commonly used antimicrobials in Salmonella spp. and Campylobacter isolates from humans and animals. Combined resistance to critically important antimicrobials was mainly observed at low levels except in some Salmonella serotypes and in C. coli in some countries. The reporting of a number of CP-producing E. coli isolates (harbouring bla _OXA-48, bla _OXA-181, and bla _NDM-5 genes) in pigs, bovines and meat thereof by a limited number of MSs (4) in 2021, requests a thorough follow-up. The temporal trend analyses in both key outcome indicators (rate of complete susceptibility and prevalence of ESBL-/AmpC- producers) showed that encouraging progress have been registered in reducing AMR in food-producing animals in several EU MSs over the last years.

A review of horses as a source of spreading livestock-associated methicillin-resistant Staphylococcus aureus to human health

Livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) was first discovered in horses in 1989. Since then, LA-MRSA has begun to be considered an important strain of pathogenic bacteria in horses, which can cause LA-MRSA infection and colonization in humans with public health impacts. The anterior nares are the primary site of LA-MRSA colonization in horses, although LA-MRSA colonization may also occur in the gastrointestinal tract in horses. LA-MRSA-infected horses typically exhibit clinical infection or may not exhibit clinical infection. There are two potential risks associated with LA-MRSA colonization in horses: The possibility of disease development in horses infected with LA-MRSA and the possibility of LA-MRSA transfer to humans and other horses. The diagnosis of LA-MRSA in horses can be made by conducting in vitro sensitivity testing for oxacillin and cefoxitin, and then followed by a molecular test using polymerase chain reaction. LA-MRSA transmission in animal hospitals and on farms is most likely due to contact with horses infected or colonized by LA-MRSA. The history of prior antibiotic administration, history of prior LA-MRSA colonization, and length of equine hospitalization were described as risk factors in cases of infection and colonization of LA-MRSA in horses. Nebulized antibiotics may be a viable alternative to use in horses, but nebulized antibiotics are only used in horses that are persistently colonized with LA-MRSA. Controlling the spread of LA-MRSA in horses can be done by regularly washing horses, eradicating vectors in horse stalls such as rats, and maintaining the cleanliness of the stable and animal hospital environment. Meanwhile, cleaning hands, using gloves, and donning protective clothes are ways that humans can prevent the transmission of LA-MRSA when handling horses. This review will explain the definition of LA-MRSA in general, LA-MRSA in horses, the epi­demiology of LA-MRSA in horses, the diagnosis of LA-MRSA in horses, the transmission of LA-MRSA in horses, risk factors for spreading LA-MRSA in horses, public health impact, treatment of LA-MRSA infection in horses, and control of the spread of LA-MRSA in horses.

Antimicrobial prescribing and antimicrobial resistance surveillance in equine practice

BACKGROUND

Antimicrobial resistance (AMR) is an increasingly serious threat to human and animal health, therefore responsible use of antimicrobials in equine practice is vital. There is a need to have accurate, up to date data on antimicrobial prescribing in equine practice in the UK.

OBJECTIVES

To characterise current antimicrobial prescribing practices by equine veterinarians and to describe surveillance, audit processes and identification of AMR.

STUDY DESIGN

Online cross-sectional, questionnaire-based survey.

METHODS

An online questionnaire targeting veterinarians who treat horses in the UK and Europe was distributed. The questionnaire collected data on participants' country of origin, practice policies, prescribing practices including use of high priority critical antimicrobials. Four common clinical case-based scenarios were included to further explore prescribing practice. Responses were compared using both descriptive statistics and multivariable logistic regression models.

RESULTS

Questionnaires were completed by 264 veterinarians from Europe (n=33/264) and the UK (n=231/264); 87% respondents worked only with horses and 67% worked at premises with hospitalisation facilities. Approximately half of respondents (54.4%) had a written antimicrobial use or stewardship policy within their practice. Over half of respondents did not perform any environmental surveillance (54.2%), audit of clinical infections (53.1%) or audit of infection control (57.1%). Potentiated sulphonamides were cited as the most used antimicrobial, although 44% reported using enrofloxacin in the last year and 66% used 3^rd or 4^th generation cephalosporins. Prophylactic antimicrobials before clean surgery were frequently/always prescribed by 48% respondents and 24% respondents frequently/always prescribed antimicrobials post-operatively in clean surgery.

MAIN LIMITATIONS

Potential selection bias of respondents, given individuals volunteered to take part in the survey.

CONCLUSIONS

Compared to a previous similar study conducted in 2009, overall antimicrobial usage appeared to be declining in clinical scenarios and a greater proportion of practices now have stewardship policies. However, the use of high priority critical antimicrobials is still relatively common in equine practice in the UK and Europe.

Assessment of listing and categorisation of animal diseases within the framework of the Animal Health Law (Regulation (EU) No 2016/429): antimicrobial-resistant Staphylococcus aureus in cattle and horses

Staphylococcus aureus (S. aureus) was identified among the most relevant antimicrobial-resistant (AMR) bacteria in the EU for cattle and horses in previous scientific opinions. Thus, it has been assessed according to the criteria of the Animal Health Law (AHL), in particular criteria of Article 7 on disease profile and impacts, Article 5 on its eligibility to be listed, Annex IV for its categorisation according to disease prevention and control rules as in Article 9, and Article 8 for listing animal species related to the bacterium. The assessment has been performed following a methodology previously published. The outcome is the median of the probability ranges provided by the experts, which indicates whether each criterion is fulfilled (lower bound ≥ 66%) or not (upper bound ≤ 33%), or whether there is uncertainty about fulfilment. Reasoning points are reported for criteria with uncertain outcome. According to the assessment here performed, it is uncertain whether AMR S. aureus can be considered eligible to be listed for Union intervention according to Article 5 of the AHL (60-90% probability). According to the criteria in Annex IV, for the purpose of categorisation related to the level of prevention and control as in Article 9 of the AHL, the AHAW Panel concluded that the bacterium does not meet the criteria in Sections 1, 2 and 4 (Categories A, B and D; 1-5%, 5-10% and 10-33% probability of meeting the criteria, respectively) and the AHAW Panel was uncertain whether it meets the criteria in Sections 3 and 5 (Categories C and E, 33-90% and 60-90% probability of meeting the criteria, respectively). The animal species to be listed for AMR S. aureus according to Article 8 criteria include mainly mammals, birds, reptiles and fish.

Investigation of the environmental presence of multidrug-resistant bacteria at small animal hospitals in Hungary

Multidrug-resistant bacteria can cause severe nosocomial infections in both human and veterinary clinics. The aim of this study was to investigate the presence and antibiotic susceptibility of Enterococcus, Staphylococcus and Pseudomonas strains at four small animal clinics of Hungary in 2018, as these bacteria can reliably represent the level of antimicrobial resistance in the investigated environment. A total of 177 Staphylococcus colonies were found, including 22 Staphylococcus pseudintermedius and 13 Staphylococcus aureus. As regards enterococci, 9 Enterococcus faecium, 2 E. faecalis and further 286 Enterococcus strains were isolated. The number of Pseudomonas aeruginosa isolates (n = 34) was considered too low for relevant susceptibility testing. Among staphylococci, the highest resistance was found to sulphamethoxazole (82.9%), penicillin (65.7%) and erythromycin (54.3%), while in the case of enterococci, resistance to norfloxacin and rifampicin was the most common, with 25.5% of the strains being resistant to both antibiotics. Ten methicillin-resistant S. pseudintermedius (MRSP) and six vancomycin-resistant Enterococcus (VRE) strains could be identified. Only 5.7% of the Staphylococcus isolates were susceptible to all tested agents, while this ratio was 36.2% among enterococci. The results of this study have revealed a high prevalence of antibiotic-resistant bacteria in Hungarian small animal clinics, which highlights the importance of regular disinfection processes and stringent hygiene measures in veterinary clinics.

Surgical hand preparation in an equine hospital: Comparison of general practice with a standardised protocol and characterisation of the methicillin-resistant Staphylococcus aureus recovered

Presurgical hand asepsis is part of the daily routine in veterinary medicine. Nevertheless, basic knowledge seems to be low, even among specialised veterinary surgeons. The major objectives of our study were to assess current habits for presurgical hand preparation (phase 1) among personnel in a veterinary hospital and their effectiveness in reducing bacteria from hands in comparison to a standardised protocol (phase 2). Assessment of individual habits focused on time for hand washing and disinfection, the amount of disinfectant used, and the usage of brushes. The standardised protocol defined hand washing for 1 min with liquid neutral soap without brushing and disinfection for 3 min. All participants (2 surgeons, 8 clinic members, 32 students) used Sterillium®. Total bacterial counts were determined before and after hand washing, after disinfection, and after surgery. Hands were immersed in 100 ml sterile sampling fluid for 1 min and samples were inoculated onto Columbia sheep blood agar using the spread-plate method. Bacterial colonies were manually counted. Glove perforation test was carried out at the end of the surgical procedure. Differences in the reduction of relative bacterial numbers between current habits and the standardised protocol were investigated using Mann-Whitney-Test. The relative increase in bacterial numbers as a function of operation time (≤60 min, >60 min) and glove perforation as well as the interaction of both was investigated by using ANOVA. Forty-six and 41 preparations were carried out during phase 1 and phase 2, respectively. Individual habits differed distinctly with regard to time (up to 8 min) and amount of disinfectant (up to 48 ml) used both between participants and between various applications of a respective participant. Comparison of current habits and the standardised protocol revealed that the duration of hand washing had no significant effect on reducing bacteria. Contrary, the reduction in bacterial numbers after disinfection by the standardised protocol was significantly higher (p<0.001) compared to routine every-day practice. With regard to disinfection efficacy, the standardised protocol completely eliminated individual effects. The mean reduction in phase 1 was 90.72% (LR = 3.23; right hand) and 89.97% (LR = 3.28; left hand) compared to 98.85% (LR = 3.29; right hand) and 98.92% (LR = 3.47; left hand) in phase 2. Eight participants (19%) carried MRSA (spa type t011, CC398) which is well established as a nosocomial pathogen in veterinary clinics. The isolates could further be assigned to a subpopulation which is particularly associated with equine clinics (mainly t011, ST398, gentamicin-resistant). Glove perforation occurred in 54% (surgeons) and 17% (assistants) of gloves, respectively, with a higher number in long-term invasive procedures. Overall, bacterial numbers on hands mainly increased over time, especially when glove perforation occurred. This was most distinct for glove perforations on the left hand and with longer operating times. Our results demonstrate that standardised protocols highly improve the efficacy of hand asepsis measures. Hence, guiding standardised protocols should be prerequisite to ensure state-of-the-art techniques which is essential for a successful infection control intervention.

Experimental Evidence Reveals Both Cross-Infection and Cross-Contamination Risk of Embryo Storage in Liquid Nitrogen Biobanks

Simple Summary

This study was conducted to demonstrate the potential hazards of cross-infection and cross-contamination of embryos during storage in liquid nitrogen biobanks. For the harmless and successful cryopreservation of embryos, the vitrification method must be chosen meticulously to guarantee not only a high post-thaw survival of embryos, but also to reduce the risk of disease transmission when those embryos are in storage for long periods.

Abstract

In recent decades, gamete and embryo cryopreservation have become routine procedures in livestock and human assisted reproduction. However, the safe storage of germplasm and the prevention of disease transmission continue to be potential hazards of disease transmission through embryo transfer. This study aimed to demonstrate the potential risk of cross-infection of embryos from contaminated liquid nitrogen, and cross-contamination of sterile liquid nitrogen from infected embryos in naked and closed devices. Additionally, we examined the effects of antibiotic-free media on culture development of infected embryos. The study was a laboratory-based analysis using rabbit as a model. Two experiments were performed to evaluate both cross-infection (liquid nitrogen to embryos) and cross-contamination (embryos to liquid nitrogen) of artificially inoculated Salmonella Typhimurium, Staphylococcus aureus, Enterobacter aerogenes, and Aspergillus brasiliensis. Rapid cooling through vitrification was conducted on rabbit embryos, stored for a year, thawed, and cultured. In vivo produced late morulae–early blastocyst stages (72 h) embryos were used (n = 480). Embryos were cultured for 1 h in solutions with and without pathogens. Then, the embryos were vitrified and stored in naked and closed devices for one year in two liquid nitrogen biobanks (one pathogen-free and the other artificially contaminated). Embryos were warmed and cultured for a further 48 h, assessing the development and the presence of microorganism (chromogenic media, scanning electron microscopy). Embryos stored in naked devices in artificially contaminated liquid nitrogen became infected (12.5%), while none of the embryos stored in closed devices were infected. Meanwhile, storage of artificially infected embryos incurred liquid nitrogen biobank contamination (100%). Observations by scanning electron microscopy revealed that all the microorganisms were caught in the surface of embryos after the vitrification-thawed procedure. Nevertheless, embryos cultured in antibiotics and antimycotic medium developed to the hatched blastocyst stage, while artificially infected embryos cultured in antibiotic-free medium failed to develop. In conclusion, our findings support that both cross-contamination and cross-infection during embryo storage in liquid nitrogen biobanks are plausible. So, to ensure biosafety for the cryogenic storage, closed systems that avoid direct contact with liquid nitrogen must be used. Moreover, it seems essential to provide best practice guidelines for the cryogenic preservation and storage of gametes and embryos, to define appropriate quality and risk management procedures.

Low prevalence of livestock-associated methicillin-resistant Staphylococcus aureus clonal complex 398 and mecC MRSA among human isolates in North-West England

AIMS

Livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) is an important public health problem in many countries. Despite reports of such isolates being found in both animals and humans in the United Kingdom few data are available on the prevalence in humans of such isolates. A prevalence study was therefore undertaken in the north-west of England.

METHODS AND RESULTS

One thousand two hundred and forty-two human MRSA isolates collected during 2015 were screened by PCR to detect two of the major forms of LA-MRSA: clonal complex (CC)398 and mecC MRSA. Isolates identified were further characterized by antimicrobial susceptibility testing and whole-genome sequencing using HiSeq technology. A single mecC MRSA isolate and three CC398 LA-MRSA were identified among the isolates screened. All four isolates were from MRSA screening. A phylogenetic analysis, including previously sequenced isolates from the United Kingdom, provided strong evidence for the genomic and epidemiological linkage between a pair of animal and human isolates of CC398 LA-MRSA in England. These data are indicative of animal and humans isolates of CC398 LA-MRSA being involved in the same transmission network and is the first demonstration of such closely linked animal and human isolates of this lineage in the UK.

CONCLUSIONS

The study indicates there is a low prevalence of CC398 LA-MRSA and mecC MRSA among MRSA isolates in the sampled population.

SIGNIFICANCE AND IMPACT OF THE STUDY

While the study demonstrates that LA-MRSA were rare among human MRSA isolates in the sampled population, the data provide a baseline for the future surveillance of what is a significant public health challenge in some regions. The demonstration of linked human and animal isolates of CC398 LA-MRSA, supported by genomic and epidemiological data, reinforces the need for such surveillance and for continued awareness of the risks that LA-MRSA may pose in the UK.

Livestock-Associated Methicillin-Resistant Staphylococcus aureus From Animals and Animal Products in the UK

Livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) is an emerging problem in many parts of the world. Although animal-adapted LA-MRSA has been known for many years, recent reports suggest a possible increasing trend in the zoonotic transmission of LA-MRSA in Europe. Since its emergence in the early 2000's, several investigations have indicated that persons in prolonged, repeated contact with affected livestock are at a higher risk of becoming colonized with LA-MRSA. LA-MRSA monitoring in livestock is voluntary under current EU legislation, and not all member states, including the UK, participate. UK LA-MRSA isolates have been detected through scanning surveillance, where samples are submitted from clinically diseased livestock for diagnostic investigation, and research studies. Surveys conducted on retail beef, pig and poultry meat on sale in the UK have also detected LA-MRSA. Taken together these results suggest that LA-MRSA is present in the UK, possibly at low prevalence level, as suggested by available evidence. In this review, we examine the data available from UK livestock and animal products, and make recommendations for future. We also review the findings from whole genome sequencing (WGS) of the possible lineage of some UK livestock isolates.

Surgical Site Infections Caused by Highly Virulent Methicillin-Resistant Staphylococcus aureus Sequence Type 398, China

We identified 2 methicillin-resistant Staphylococcus aureus strains of sequence type 398 from surgical site infections in China. Genetic analysis and clinical data from these strains suggested that they were human-related but sporadic. Hemolysis analysis and mouse-skin infection models indicated a high virulence potential for these strains.

Outbreaks of a Methicillin-Resistant Staphylococcus aureus Clone ST398-t011 in a Hungarian Equine Clinic: Emergence of Rifampicin and Chloramphenicol Resistance After Treatment with These Antibiotics

Between July 2011 and May 2016, a total of 40 Staphylococcus aureus strains originating from 36 horses were confirmed as methicillin resistant (methicillin-resistant Staphylococcus aureus [MRSA]) in a university equine clinic. An additional 10 MRSA strains from 36 samples of clinic workers were obtained in October 2017. The first equine isolate represented the sequence type ST398, spa-type t011, and SCCmec IV. This isolate was resistant to a wide spectrum of antimicrobial agents. MRSA strains with the same genotype and with very similar resistance profiles were isolated on 21 more occasions from September 2013 to September 2014. A second outbreak occurred from May 2015 until May 2016. The first isolate in this second outbreak shared the same genotype, but was additionally resistant to chloramphenicol. The second isolate from August 2015 also showed resistance to rifampicin. The clone was isolated 18 times. Most of the human isolates shared the same genotype as the isolates from horses and their resistance patterns showed only slight differences. We can conclude that the MRSA-related cases at the Department and Clinic of Equine Medicine were all nosocomial infections caused by the same clonal lineage belonging to the clonal complex 398. The clonal complex 398 of equine origin is reported for the first time in Hungary. In addition, our observation of the emergence of new resistance to antimicrobial agents within the clonal lineage after treatment with antibiotics is of concern. Strict hygiene regulations have been introduced to lower the incidence of MRSA isolation and the related clinical disease.

A cross-sectional study of methicillin-resistant Staphylococcus aureus at the equine-human interface

The present study aimed at investigating the percent prevalence of methicillin-resistant Staphylococcus aureus (MRSA) in equines and associated personnel. A total of 150 swabs of equines and 50 nasal swab samples of associated personnel were collected. These samples were processed in mannitol salt broth for enrichment. A total of 175 nasal swab samples changed the broth color from pink to yellow which were detected as samples containing S. aureus. These samples were processed further on specific media, namely mannitol salt agar, Staph-110, and blood agar, for phenotypic and Gram's staining-based confirmation of S. aureus isolates. Out of these 175 S. aureus-positive samples, 150 were of equine and 25 were of human origin. Identification of MRSA isolates in 175 S. aureus-positive samples was carried out by antimicrobial susceptibility testing by disc diffusion method. Results showed the presence of MRSA in 87 samples, out of which 81 samples were collected from equines and six samples from humans. Results of antibiotic testing revealed that percentage positivity of MRSA was higher (54%) in equines as compared with the associated personnel (24%). Most resistant antibiotics against MRSA isolates were oxacillin and methicillin while linezolid was found to be the most sensitive antibiotic against MRSA. In conclusion, our findings indicated prevalence of MRSA in equines and associated personnel evidencing an occupational risk of contracting MRSA from horses.