Methicillin-resistant Staphylococcus aureus (MRSA) isolated from small and exotic animals at a university hospital during routine microbiological examinations

Prevalence of MRSA in canine and feline clinical samples from one-third of veterinary practices in Germany from 2019-2021

BACKGROUND

MRSA is a major contributor to AMR-related deaths. The WHO's global action plan emphasizes a One Health approach, acknowledging the connection between humans and their companion animals. It is agreed on that comprehensive AMR surveillance is needed.

OBJECTIVES

This study provides a large-scale overview of MRSA occurrence in cats and dogs in Germany, serving as a foundation for continuous surveillance.

METHODS

The study analysed all results of canine and feline bacterial diagnostic samples from a large laboratory, encompassing samples received from veterinary practices between January 2019 and December 2021. MRSA prevalence between host species, sample types and geographical distribution were compared. Additionally, data were contrasted with human MRSA surveillance data from Germany.

RESULTS

Samples originated from 3491 German veterinary practices, representing 33.1% of practices and clinics nationally. Bacterial examination results from 175 171 samples were analysed, identifying S. aureus in 5526 of these samples (3.2% isolation rate). S. aureus in clinical samples was more prevalent in cats (5.6%) than dogs (2.0%). Methicillin resistance was found in 17.8% of S. aureus samples and was higher in dogs (20.4%, 95%CI 18.9-22.0) than cats (15.6%, 95%CI 14.3-17.0). The highest MRSA prevalence was found in canine wound samples (32%), compared to skin/soft tissue, respiratory tract and other (<23% respectively).

CONCLUSION

The study reveals a 17.8% MRSA prevalence, which is higher than the human outpatient MRSA prevalence (5.4%). Restriction and regulation of veterinary antibiotic use should be validated with AMR surveillance. Our study shows that this is feasible in companion animals with significant coverage.

Risk Communication on Zoonoses and Antimicrobial Resistance-How Do Exotic Pet Owners Perceive the Communication of Their Veterinarians?

Exotic animals traded and kept as pets can transmit a variety of diseases to humans and other animals, and vice versa. Therefore, it is essential for pet owners, particularly vulnerable groups, to be informed about associated risks. Veterinarians play a crucial role in informing pet owners about health risks associated with zoonotic pathogens and antimicrobial resistance (AMR) and should, therefore, have good communication skills to effectively transfer information to pet owners. Thus, exotic pet owners in Germany were surveyed on animal husbandry, veterinary consultation and risk communication. To evaluate the perception of communication, a self-developed questionnaire was used to derive a communication score. The perception of veterinarian communication received a high average score showing a high level of satisfaction. The duration of the veterinarian-client relationship was associated with better communication perception, and the frequency of communication on zoonoses and AMR was associated with the presence of a permanent veterinarian. However, the results indicated that the frequency of disseminated information on zoonoses and/or AMR from veterinarians was lower than desired by the pet owners. Therefore, more educational material on zoonoses and AMR should be made available, and the awareness concerning risk communication should be increased by further education and training at universities.

Bacteriophage-driven emergence and expansion of Staphylococcus aureus in rodent populations

Human activities such as agriculturalization and domestication have led to the emergence of many new pathogens via host-switching events between humans, domesticated and wild animals. Staphylococcus aureus is a multi-host opportunistic pathogen with a global healthcare and economic burden. Recently, it was discovered that laboratory and wild rodents can be colonised and infected with S. aureus, but the origins and zoonotic potential of rodent S. aureus is unknown. In order to trace their evolutionary history, we employed a dataset of 1249 S. aureus genome sequences including 393 of isolates from rodents and other small mammals (including newly determined sequences for 305 isolates from 7 countries). Among laboratory mouse populations, we identified multiple widespread rodent-specific S. aureus clones that likely originated in humans. Phylogeographic analysis of the most common murine lineage CC88 suggests that it emerged in the 1980s in laboratory mouse facilities most likely in North America, from where it spread to institutions around the world, via the distribution of mice for research. In contrast, wild rodents (mice, voles, squirrels) were colonized with a unique complement of S. aureus lineages that are widely disseminated across Europe. In order to investigate the molecular basis for S. aureus adaptation to rodent hosts, genome-wide association analysis was carried out revealing a unique complement of bacteriophages associated with a rodent host ecology. Of note, we identified novel prophages and pathogenicity islands in rodent-derived S. aureus that conferred the potential for coagulation of rodent plasma, a key phenotype of abscess formation and persistence. Our findings highlight the remarkable capacity of S. aureus to expand into new host populations, driven by the acquisition of genes promoting survival in new host-species.

The Epidemiology of Animal-Associated Methicillin-Resistant Staphylococcus aureus

Methicillin-resistant Staphylococcus aureus (MRSA) remains an important etiological factor of human and animal infectious diseases, causing significant economic losses not only in human healthcare but also in the large-scale farming sector. The constantly changing epidemiology of MRSA observed globally affects animal welfare and raises concerns for public health. High MRSA colonization rates in livestock raise questions about the meaning of reservoirs and possible transmission pathways, while the prevalence of MRSA colonization and infection rates among companion animals vary and might affect human health in multiple ways. We present the main findings concerning the circulation of animal-associated MRSA (AA-MRSA) in the environment and factors influencing the direction, mechanisms, and routes of its transmission. Studies have shown it that S. aureus is a multi-host bacterial pathogen; however, its adaptation mechanisms enabling it to colonize and infect both animal and human hosts are still rarely discussed. Finally, we elaborate on the most successful strategies and programs applied limiting the circulation of AA-MRSA among animals and humans. Although MRSA strains colonizing animals rarely infect humans, they undergo host-adaptive evolution enabling them to spread and persist in human populations.

Does colonization with MRSA, ESBL - producing Enterobacteriaceae, and/or Acinetobacter baumannii - increase the risk for postoperative surgical site infection?

OBJECTIVE

Evaluation of the role of indicator pathogens in equine surgical site infection (SSI) and other infection-promoting factors.

STUDY DESIGN

Cross-sectional study.

ANIMALS

Horses presenting with an open injury or surgical colic during 1.5 years.

METHODS

A nasal swab and a faecal sample were collected from every patient upon admission. Furthermore, a wound swab was collected from wounds of injured horses. Details on the wounds and procedures were documented. Laparotomy incisions and injuries were monitored for signs suggesting infection.

RESULTS

In total, 156 horses presented because of a surgical colic (n = 48) or open injuries (n = 108). Thirteen surgical colic patients and three injured horses did not survive beyond 24 h, and four injured horses were discharged from the clinic at the day of admission. SSIs occurred in 31 (30.7%) injured horses and 11 (31.4%) horses after laparotomy. Regarding injuries, general anaesthesia increased the risk of developing a WI compared to sedation. Indicator pathogens were cultured from 29/42 SSI. In total, 10/11 infected laparotomy incisions and 19/31 injuries with SSI tested positive for multidrug-resistant pathogens (MDRPs) . Indicator pathogens were not detected at admission in any of the horses that developed incisional SSIs after laparotomy but were detected in two of the injured horses that developed SSIs.

CONCLUSION

MDRPs were identified in almost 70% of the SSI. Less than 5% of the affected animals were colonized with the same pathogen before admission, indicating that colonization with MDR pathogens is only one of the crucial factors for the development of SSI.

CLINICAL SIGNIFICANCE

Colonization with MDRP seems not to predispose horses to MDR SSIs.

Bats Are Carriers of Antimicrobial-Resistant Staphylococcaceae in Their Skin

Bats have emerged as potential carriers of zoonotic viruses and bacteria, including antimicrobial-resistant bacteria. Staphylococcaceae has been isolated from their gut and nasopharynx, but there is little information about Staphylococcaceae on bat skin. Therefore, this study aimed to decipher the Staphylococci species in bat skin and their antimicrobial susceptibility profile. One hundred and forty-seven skin swabs were collected from bats during the spring and summer of 2021 and 2022. Bats were captured in different areas of the Metropolitan Region of São Paulo, Brazil, according to the degree of anthropization: Area 1 (Forested), Area 2 (Rural), Area 3 (Residential-A), Area 4 (Slum-- up to two floors), Area 5 (Residential-B-condo buildings), and Area 6 (Industrial). Swabs were kept in peptone water broth at 37 °C for 12 h when bacterial growth was streaked in Mannitol salt agar and incubated at 37 °C for 24 h. The disc-diffusion test evaluated antimicrobial susceptibility. Staphylococcaceae were isolated from 42.8% of bats, mostly from young, from the rural area, and during summer. M. sciuri was the most frequent species; S. aureus was also isolated. About 95% of isolates were resistant to at least one drug, and most strains were penicillin resistant. Eight isolates were methicillin resistant, and the mecA gene was detected in one isolate (S. haemolyticus). Antimicrobial resistance is a One Health issue that is not evaluated enough in bats. The results indicate that bats are carriers of clinically meaningful S. aureus and antimicrobial-resistant bacteria. Finally, the results suggest that we should intensify action plans to control the spread of resistant bacteria.

Evidence of Antimicrobial Resistance in Bats and Its Planetary Health Impact for Surveillance of Zoonotic Spillover Events: A Scoping Review

As a result of the COVID-19 pandemic, as well as other outbreaks, such as SARS and Ebola, bats are recognized as a critical species for mediating zoonotic infectious disease spillover events. While there is a growing concern of increased antimicrobial resistance (AMR) globally during this pandemic, knowledge of AMR circulating between bats and humans is limited. In this paper, we have reviewed the evidence of AMR in bats and discussed the planetary health aspect of AMR to elucidate how this is associated with the emergence, spread, and persistence of AMR at the human-animal interface. The presence of clinically significant resistant bacteria in bats and wildlife has important implications for zoonotic pandemic surveillance, disease transmission, and treatment modalities. We searched MEDLINE through PubMed and Google Scholar to retrieve relevant studies (n = 38) that provided data on resistant bacteria in bats prior to 30 September 2022. There is substantial variability in the results from studies measuring the prevalence of AMR based on geographic location, bat types, and time. We found all major groups of Gram-positive and Gram-negative bacteria in bats, which are resistant to commonly used antibiotics. The most alarming issue is that recent studies have increasingly identified clinically significant multi-drug resistant bacteria such as Methicillin Resistant Staphylococcus aureus (MRSA), ESBL producing, and Colistin resistant Enterobacterales in samples from bats. This evidence of superbugs abundant in both humans and wild mammals, such as bats, could facilitate a greater understanding of which specific pathways of exposure should be targeted. We believe that these data will also facilitate future pandemic preparedness as well as global AMR containment during pandemic events and beyond.

Cultivable Bacteria Associated with the Microbiota of Troglophile Bats

Simple Summary

Troglophile bats live in colonies, often in sites exploited for agro-pastoral purposes. Determining the composition of the microbiome of bats is an important step in understanding their ecology and biology and can also provide information on the spread of pathogenic bacteria in their populations. This study aimed to determine how epidemiological factors shape the microbiome of troglophile bats and evaluate the occurrence of potentially pathogenic bacterial species. A total of 413 Gram-negative and 183 Gram-positive strains were isolated from 189 individuals of four species of troglophile bats living in Sicilian and Calabrian territory (Italy). Besides few potentially pathogenic bacteria, several strains with a hypothesized symbiotic role were found.

Abstract

Background: The study of bats is of significant interest from a systematic, zoogeographic, ecological, and physiological point of view. The aim of this study is to investigate the culturable aerobic enteric, conjunctival, and oral bacterial flora of bats to determine their physiological microbiome and to investigate the possible occurrence of pathogenic bacteria. Methods: Five hundred and sixty-seven samples were collected from 189 individuals of four species of troglophile bats (Myotis myotis, Myotis capaccinii, Miniopterus schreibersii, and Rhinolophus hipposideros) living in Sicilian and Calabrian territory (Italy). All samples were tested for Gram-negative bacteria; conjunctival and oral swabs were also submitted to bacteriological examination for Gram-positive bacteria. Results: Four hundred thirteen Gram-negative strains were isolated. Of these, 377 belonged to 17 different genera of the family Enterobacteriaceae and 30 to five other families. One hundred eighty-three Gram-positive strains were isolated. Of these, 73 belonged to the Staphylococcaceae family, 72 to the Bacillaceae family and 36 to four other families. Besides some potentially pathogenic strains, several bacterial species have been found that are common to all the bat species studied. These could perhaps play a physiological or nutritional role. Conclusion: A great variety of bacterial species were identified in the cultivable microbiota of southern-Italian troglophile bats, including several potentially pathogenic strains and numerous putatively symbiotic species.

Sequence Analysis of Novel Staphylococcus aureus Lineages from Wild and Captive Macaques

Staphylococcus aureus is a widespread and common opportunistic bacterium that can colonise or infect humans as well as a wide range of animals. There are a few studies of both methicillin-susceptible S. aureus (MSSA) and methicillin-resistant S. aureus (MRSA) isolated from monkeys, apes, and lemurs, indicating a presence of a number of poorly or unknown lineages of the pathogen. In order to obtain insight into staphylococcal diversity, we sequenced strains from wild and captive individuals of three macaque species (Macaca mulatta, M. assamensis, and M. sylvanus) using Nanopore and Illumina technologies. These strains were previously identified by microarray as poorly or unknown strains. Isolates of novel lineages ST4168, ST7687, ST7688, ST7689, ST7690, ST7691, ST7692, ST7693, ST7694, ST7695, ST7745, ST7746, ST7747, ST7748, ST7749, ST7750, ST7751, ST7752, ST7753, and ST7754 were sequenced and characterised for the first time. In addition, isolates belonging to ST2990, a lineage also observed in humans, and ST3268, a MRSA strain already known from macaques, were also included into the study. Mobile genetic elements, genomic islands, and carriage of prophages were analysed. There was no evidence for novel host-specific virulence factors. However, a conspicuously high rate of carriage of a pathogenicity island harbouring edinB and etD2/etE as well as a higher number of repeat units within the gene sasG (encoding an adhesion factor) than in human isolates were observed. None of the strains harboured the genes encoding Panton-Valentine leukocidin. In conclusion, wildlife including macaques may harbour an unappreciated diversity of S. aureus lineages that may be of clinical relevance for humans, livestock, or for wildlife conservation, given the declining state of many wildlife populations.

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.

Staphylococcus aureus Causing Skin and Soft Tissue Infections in Companion Animals: Antimicrobial Resistance Profiles and Clonal Lineages

Staphylococcus aureus is a relevant agent of skin and soft tissue infections (SSTIs) in animals. Fifty-five S. aureus comprising all SSTI-related isolates in companion animals, collected between 1999 and 2018 (Lab 1) or 2017 and 2018 (Lab 2), were characterized regarding susceptibility to antibiotics and heavy metals and carriage of antimicrobial resistance determinants. Clonal lineages were established by PFGE, MLST and agr typing. Over half of the isolates (56.4%, 31/55) were methicillin-resistant S. aureus (MRSA), and 14.5% showed a multidrug resistance (MDR) phenotype. Resistance was most frequently observed for beta-lactams (81.8%, related to blaZ and/or mecA), fluoroquinolones (56.4%) and macrolides/lincosamides (14.5%, related to erm(A) or erm(C)). The distributions of heavy-metal MICs allowed the detection of non-wild-type populations associated with several resistance genes. The collection showed genetic diversity, with prevalence of clonal lineage ST22-agrI (45.5%, 25/55), comprising only MRSA isolates, and several less frequently detected clones, including ST5-agrII (14.6%, 8/55), ST398-agrI (9.1%, 5/55) and ST72-agrI (7.3%, 4/55). This work highlights the high frequency of SSTI-related MRSA strains that reflect the clonal lineages circulating both in companion animals and humans in Portugal, reinforcing the need for a One Health approach when studying staphylococci causing infections in companion animals.

The Prevalence and Molecular Biology of Staphylococcus aureus Isolated from Healthy and Diseased Equine Eyes in Egypt

This work aimed to characterize S. aureus isolates from the eyes of healthy and clinically affected equines in the Kafrelsheikh Governorate, Egypt. A total of 110 animals were examined for the presence of S. aureus, which was isolated from 33 animals with ophthalmic lesions and 77 healthy animals. We also investigated the antimicrobial resistance profile, oxacillin resistance mechanism, and the major virulence factors implicated in many studies of the ocular pathology of pathogenic S. aureus. The association between S. aureus eye infections and potential risk factors was also investigated. The frequency of S. aureus isolates from clinically affected equine eyes was significantly higher than in clinically healthy equids. A significant association was found between the frequency of S. aureus isolation from clinically affected equine eyes and risk factors including age and season but not with sex or breed factors. Antimicrobial resistance to common antibiotics used to treat equine eyes was also tested. Overall, the isolates showed the highest sensitivity to sulfamethoxazole (100%) and the highest resistance to cephalosporin (90.67%) and oxacillin (90.48%). PCR was used to demonstrate that mecA was present in 100% of oxacillin- and β-lactam-resistant S. aureus strains. The virulence factor genes Spa (x region), nuc, and hlg were identified in 62.5%, 100%, and 56%, of isolates, respectively, from clinically affected equines eyes. The severity of the eye lesions increased in the presence of γ-toxin-positive S. aureus. The phylogenetic tree of the Spa (x region) gene indicated a relationship with human reference strains isolated from Egypt as well as isolates from equines in Iran and Japan. This study provides insight into the prevalence, potential risk factors, clinical pictures, zoonotic potential, antimicrobial resistance, and β-lactam resistance mechanism of S. aureus strains that cause eye infection in equines from Egypt.

Staphylococcus aureus in Agriculture: Lessons in Evolution from a Multispecies Pathogen

Staphylococcus aureus is a formidable bacterial pathogen that is responsible for infections in humans and various species of wild, companion, and agricultural animals. The ability of S. aureus to move between humans and livestock is due to specific characteristics of this bacterium as well as modern agricultural practices. Pathoadaptive clonal lineages of S. aureus have emerged and caused significant economic losses in the agricultural sector. While humans appear to be a primary reservoir for S. aureus, the continued expansion of the livestock industry, globalization, and ubiquitous use of antibiotics has increased the dissemination of pathoadaptive S. aureus in this environment. This review comprehensively summarizes the available literature on the epidemiology, pathophysiology, genomics, antibiotic resistance (ABR), and clinical manifestations of S. aureus infections in domesticated livestock. The availability of S. aureus whole-genome sequence data has provided insight into the mechanisms of host adaptation and host specificity. Several lineages of S. aureus are specifically adapted to a narrow host range on a short evolutionary time scale. However, on a longer evolutionary time scale, host-specific S. aureus has jumped the species barrier between livestock and humans in both directions several times. S. aureus illustrates how close contact between humans and animals in high-density environments can drive evolution. The use of antibiotics in agriculture also drives the emergence of antibiotic-resistant strains, making the possible emergence of human-adapted ABR strains from agricultural practices concerning. Addressing the concerns of ABR S. aureus, without negatively affecting agricultural productivity, is a challenging priority.

Medical Causes of Feather Damaging Behavior

Feather damaging behavior (FDB), also referred to as feather picking, feather plucking, or pterotillomania, is one of the most common and frustrating clinical presentations in captive psittacines. The clinical approach to identify underlying medical conditions associated with FDB is reviewed. Primary feather or skin diseases as well as systemic diseases may lead to this syndrome. This article focuses on the medical causes of FDB documented in the current avian literature. Medical causes are presented using the VITAMIN D algorithm. Key components of the multifaceted therapeutic approach in managing FDB of medical origin are discussed.

Isolation and Identification of Methicillin-Resistant Staphylococcus aureus (MRSA) from Milk in Shire Dairy Farms, Tigray, Ethiopia

Antibiotic-resistant Staphylococcus aureus isolates pose a severe challenge to both veterinary and health professions and dairy cattle producers. Cross-sectional study was conducted from November 2014 to May 2015 to isolate and identify S. aureus from mastitic cows' milk and estimate the occurrence of MRSA in the dairy farms of Shire. Physical examination and California mastitis test were performed on a total of 220 dairy cows. Bacteriological isolation and identification and antibiogram testing were performed. Furthermore, multiplex polymerase chain reaction (PCR) was done for the detection of mec A and fem A genes. Out of the 220 dairy cows, 64 (29.09%) were positive for bovine mastitis, and of these, 32.81% were coagulase-positive S. aureus (CoPS). Antibiogram test results showed 100% of the isolates were resistant to penicillin G, nalidixic acid, and ampicillin, and 33.33% of the CoPS showed resistance to oxacillin (phenotypically MRSA positive). But 38.09% of the CoPS were found to be resistant and susceptible to vancomycin. PCR amplification of the seven phenotypically MRSA isolates revealed that 42.9% and 71.4% of them were found to carry fem A and mec A genes, respectively. The current study revealed the existence of alarming level of CoPS and development of multidrug resistance.

Plasma antibacterial activities in ornate (Terrapene ornata) and eastern box turtles (Terrapene carolina)

Chelonians are one of the most imperiled vertebrate taxa and many species are increasingly threatened by disease, however, the immune response in this group is understudied. We quantified the innate immune response of eastern (Terrapene carolina; EBT) and ornate (Terrapene ornate; OBT) box turtles using plasma antibacterial activity assays. Plasma from both species abolished or significantly reduced the growth of all eight bacterial species evaluated, including Salmonella typhimurium, Escherichia coli, Enterobacter cloacae, Citrobacter freundi, Bacillus subtilis, Staphylococcus epidermidis, and Staphylococcus aureus. Bactericidal capacity was greater in OBT compared to EBT, and OBT plasma retained high antibacterial activities at a broader temperature range (20-40°C) compared to EBT (30-40°C). Plasma antibacterial activity was abolished following treatment with heat, protease, and ethylenediaminetetraacetic acid, indicating that complement is likely responsible for the observed effects. Further characterization of the box turtle immune response may provide insight into the importance of infectious diseases for species conservation, enabling the development of more efficient and effective population management strategies.

The Evolutionary Genomics of Host Specificity in Staphylococcus aureus

Staphylococcus aureus is an important human bacterial pathogen that has a cosmopolitan host range, including livestock, companion and wild animal species. Genomic and epidemiological studies show that S. aureus has jumped between host species many times over its evolutionary history. These jumps have involved the dynamic gain and loss of host-specific adaptive genes, usually located on mobile genetic elements. The same functional elements are often consistently gained in jumps into a particular species. Further sampling of diverse animal species is likely to uncover an even broader host range and greater genetic diversity of S. aureus than is already known, and understanding S. aureus host specificity in these hosts will mitigate the risks of emergent human and livestock strains.

Methicillin resistant Staphylococcus aureus carriage among guinea pigs raised as livestock in Ecuador

Antimicrobial resistance is a growing problem in human and veterinary medicine. Here we show that 6.25% of the guinea pigs studied in Ecuador, raised as livestock, carry methicillin resistant Staphylococcus aureus (MRSA) in the nasopharynx and therefore may potentially play a role in the transmission of MRSA in the Andean Region of South America.

Multiple introductions of methicillin-resistant Staphylococcus aureus ST612 into Western Australia associated both with human and equine reservoirs

Staphylococcus aureus is a serious human and animal pathogen. Multilocus sequence type 612 (ST612) is the dominant methicillin-resistant S. aureus (MRSA) clone in certain South African hospitals and is sporadically isolated from horses and horse-associated veterinarians in Australia. Colonisation and infection by ST612-MRSA is increasing in Western Australia. Whole-genome sequencing was performed for 51 isolates of ST612-MRSA from Western Australian patients and healthcare workers, South African hospital patients, Australian veterinarians and New South Wales horses. Core genome phylogenies suggested that Australian equine and veterinarian-associated ST612-MRSA were monophyletic. Individual Western Australian isolates grouped either with this equine-associated lineage or more diverse lineages related to those in South African hospitals. Bioinformatic analyses of the complete ST612-MRSA reference genome SVH7513 confirmed that ST612-MRSA was closely related to ST8 USA500 MRSA. Common use of rifampicin in South Africa and equine veterinarian practice may favour ST612-MRSA in these settings. Humans and horses colonised with ST612-MRSA are potential reservoirs for MRSA in Australia.

Investigation of methicillin-resistant Staphylococcus aureus among clinical isolates from humans and animals by culture methods and multiplex PCR

Background

Staphylococcus aureus is responsible for large numbers of hospital-related and community-acquired infections. In this study, we investigated the presence of S. aureus and methicillin-resistant S. aureus (MRSA) in 100 samples from animals (55 cattle, 36 dogs, and 9 cats) and 150 samples from hospitalized human patients. The samples were collected from healthy and diseased animals and from diseased humans and included milk, wound swab, pus, exudates, nasal swab and diabetic ulcer. Initially, S. aureus was isolated and identified by colony morphology, Gram staining, and biochemical tests (catalase and coagulase tests). The S. aureus-positive samples were examined by polymerase chain reaction (PCR) to determine their MRSA status.

Results

Of the 100 animal samples, 29 were positive for S. aureus. Four samples (13.8%) from dogs were MRSA-positive, but samples from cattle and cats were MRSA-negative. Of the 150 human samples we collected, 64 were S. aureus-positive and, of these, 34 (53.1%) were MRSA-positive. Most (28%) of the MRSA samples were isolated from surgical wound swabs, followed by the pus from skin infections (11%), exudates from diabetic ulcers (6%), exudates from burns (4%), and aural swabs (3%). By contrast, a low MRSA detection rate (n = 4) was seen in the non-human isolates, where all MRSA bacteria were isolated from nasal swabs from dogs. The antimicrobials susceptibility testing results showed that S. aureus isolates with mecA genes showed resistance to penicillin (100%), oxacillin (100%), erythromycin (73.5%), ciprofloxacin (70.6%), and gentamicin (67.7%). The lowest resistance was found against ceftazidime, and no vancomycin-resistant isolates were obtained.

Conclusions

We detected S. aureus and MRSA in both human and canine specimens. Isolates were found to be resistant to some of the antimicrobials available locally. MRSA carriage in humans and animals appears to be a great threat to effective antimicrobials treatment. The prudent use of antimicrobials will reduce the antimicrobial resistance. Our findings will help to find the most appropriate treatment and to reduce antimicrobial resistance in the future by implementing prudent use of antimicrobials. Further studies are required to better understand the epidemiology of MRSA human–animal inter-species transmission in Bangladesh.

Electronic supplementary material

The online version of this article (10.1186/s12917-018-1611-0) contains supplementary material, which is available to authorized users.

Antimicrobial Resistance among Staphylococci of Animal Origin

Antimicrobial resistance among staphylococci of animal origin is based on a wide variety of resistance genes. These genes mediate resistance to many classes of antimicrobial agents approved for use in animals, such as penicillins, cephalosporins, tetracyclines, macrolides, lincosamides, phenicols, aminoglycosides, aminocyclitols, pleuromutilins, and diaminopyrimidines. In addition, numerous mutations have been identified that confer resistance to specific antimicrobial agents, such as ansamycins and fluoroquinolones. The gene products of some of these resistance genes confer resistance to only specific members of a class of antimicrobial agents, whereas others confer resistance to the entire class or even to members of different classes of antimicrobial agents, including agents approved solely for human use. The resistance genes code for all three major resistance mechanisms: enzymatic inactivation, active efflux, and protection/modification/replacement of the cellular target sites of the antimicrobial agents. Mobile genetic elements, in particular plasmids and transposons, play a major role as carriers of antimicrobial resistance genes in animal staphylococci. They facilitate not only the exchange of resistance genes among members of the same and/or different staphylococcal species, but also between staphylococci and other Gram-positive bacteria. The observation that plasmids of staphylococci often harbor more than one resistance gene points toward coselection and persistence of resistance genes even without direct selective pressure by a specific antimicrobial agent. This chapter provides an overview of the resistance genes and resistance-mediating mutations known to occur in staphylococci of animal origin.

Occurrence and molecular composition of methicillin-resistant Staphylococcus aureus isolated from ocular surfaces of horses presented with ophthalmologic disease

Severe infections due to methicillin-resistant Staphylococcus aureus (MRSA) have been increasingly recognized in virtually all fields of veterinary medicine. Our objective was to study the occurrence, phylogenetic relationships and antimicrobial resistance properties of MRSA isolated from ocular surfaces of horses prior to invasive procedures. Within a 49-week sampling period, ocular swabs obtained from 46 eyes of 44 horses, including eyes with clinical signs of conjunctivitis/blepharitis, keratitis or uveitis were screened for the presence of S. aureus. As a result, seven samples were positive for S. aureus (15.2%), with six of them being classified as MRSA (13%). In addition, all isolates were resistant or showed reduced susceptibility to tetracyclines, the aminoglycosides gentamicin and kanamycin, fluoroquinolones, and the combination sulfamethoxazole/trimethoprim. Since a very close relationship between the MRSA isolates was assumed after pulsed-field gel electrophoresis employing the restriction endonuclease ApaI, whole genome sequencing (WGS) was used to shed more light on the phylogenetic relationships and the molecular composition of all MRSA isolates. Analysis of WGS data revealed closely related MRSA belonging to sequence type 398, spa type t011 and dru type dt10q, harboring an SCCmec IV element and the Staphylococcus aureus pathogenicity island SaPIbov5. Moreover, all MRSA were positive for a beta-hemolysin converting phage carrying genes of the immune evasion cluster (IEC). Since cases of eye infections due to MRSA were often associated with fatal outcomes, more research is needed with respect to the origin of MRSA isolated from ocular surfaces to implement sufficient barrier and infection control measures.

Molecular typing of Staphylococcus aureus of different origins based on the polymorphism of the spa gene: characterization of a novel spa type

The present study was conducted to determine the molecular diversity of Staphylococcus aureus strains isolated from human, bovine and food samples based on the polymorphism of the spa gene. A total of 208 S. aureus isolated from human, bovine raw milk and food samples were assessed using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and single locus sequence typing (SLST) methods, followed by determination of spa types using Ridom SpaServer. Altogether, 15 distinct RFLP patterns were recorded (I-XV). The highest heterogeneity was observed among S. aureus isolated from humans, whereas most of bovine and food S. aureus isolates indicated certain RFLP patterns. Although most of the isolates from patients showed RFLP pattern I, none of the S. aureus isolated from carriers had this spa pattern. Besides, the results of SLST led to the characterization of 16 spa types, and one of them was a novel spa type which has been registered in Ridom SpaServer for the first time and designated as type t16929. Determination of a high number of shared RFLP patterns between human and food S. aureus isolates indicated possible transmission of S. aureus and the source of food contamination. Thus, effective hygiene measures should be taken to break transmission routes. However, it seems that S. aureus isolated from patients, carriers and bovine should be considered in a different way, since some isolates had similar patterns, while the others showed their own specific pattern.

Prevalence and Characterization of Staphylococcus aureus and Methicillin-Resistant Staphylococcus aureus on Public Recreational Beaches in Northeast Ohio

Staphylococcus aureus can cause severe life-threatening illnesses such as sepsis and endocarditis. Although S. aureus has been isolated from marine water and intertidal beach sand, only a few studies have been conducted to assess prevalence of S. aureus at freshwater recreational beaches. As such, we aimed to determine prevalence and molecular characteristics of S. aureus in water and sand at 10 freshwater recreational beaches in Northeast Ohio, USA. Samples were analyzed using standard microbiology methods, and resulting isolates were typed by spa typing and multilocus sequence typing. The overall prevalence of S. aureus in sand and water samples was 22.8% (64/280). The prevalence of methicillin-resistant S. aureus (MRSA) was 8.2% (23/280). The highest prevalence was observed in summer (45.8%; 55/120) compared to fall (4.2%; 5/120) and spring (10.0%; 4/40). The overall prevalence of Panton-Valentine leukocidin genes among S. aureus isolates was 21.4% (15/70), and 27 different spa types were identified. The results of this study indicate that beach sand and freshwater of Northeast Ohio were contaminated with S. aureus, including MRSA. The high prevalence of S. aureus in summer months and presence of human-associated strains may indicate the possibility of role of human activity in S. aureus contamination of beach water and sand. While there are several possible routes for S. aureus contamination, S. aureus prevalence was higher in sites with wastewater treatment plants proximal to the beaches.

OPHTHALMIC EXAMINATION IN COMMON KESTRELS (FALCO TINNUCULUS) FROM SOUTH KOREA

The purpose of this study was to establish reference ophthalmic findings in the common kestrel (Falco tinnunculus). Twenty healthy adult kestrels were included in this study. Ophthalmic examinations included slit lamp biomicroscopy, fundus exam, Schirmer tear test, conjunctival bacterial culture and isolation, corneal touch threshold, tonometry, and corneal diameter measurement. Mean tear production was 7.4 ± 3.27 mm/min, and mean intraocular pressure measured via applanation tonometry was 10.5 ± 3.15 mm Hg. In addition, the mean corneal touch threshold was 29.8 ± 20.1 mm, and the mean corneal diameter was 9.8 ± 1.1 mm. Of the 25 conjunctival swabs, 23 (92%) yielded bacterial growth. Most of these bacteria were gram positive (69.6%); the most predominant genus was Staphylococcus. This study presents reference values for ophthalmic examinations in common kestrels.

Livestock-associated methicillin-resistant Staphylococcus aureus is widespread in farmed mink (Neovison vison)

Livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) clonal complex (CC) 398 is widespread in the Danish pig production with around 90% of herds being positive. Since 2009, cases of CC398 LA-MRSA infections in Danish mink farmers have been observed. The objective of the study was to examine the presence of LA-MRSA in farmed mink. The investigation comprised three different sample types 1) clinical samples from carcasses submitted to the laboratory for diagnostic examination, 2) paws and pharyngeal swabs from healthy animals collected at pelting, and 3) feed samples from mink feed producers. In clinical samples, LA-MRSA was found in 34% of submissions and was most prevalent in samples from paws (33%) and pharynx (17%), followed by nasal and intestinal samples (each 13%), whereas it was never detected in perineal samples. LA-MRSA was found in healthy animals on 40% of the investigated farms, including paw samples (29%) and pharyngeal samples (16%). Twenty out of the 108 feed samples from feed producers were positive for LA-MRSA. The dominant spa-types were t034 and t011 associated to CC398, corresponding to the dominant spa-types detected in the Danish pig production, from which slaughter offal is used for mink feed. The spa-types, the high prevalence of LA-MRSA on paws and in pharynx, and its detection in feed samples, suggest feed as a possible source of LA-MRSA in mink.

Diversity of Staphylococcus aureus Isolates in European Wildlife

Staphylococcus aureus is a well-known colonizer and cause of infection among animals and it has been described from numerous domestic and wild animal species. The aim of the present study was to investigate the molecular epidemiology of S. aureus in a convenience sample of European wildlife and to review what previously has been observed in the subject field. 124 S. aureus isolates were collected from wildlife in Germany, Austria and Sweden; they were characterized by DNA microarray hybridization and, for isolates with novel hybridization patterns, by multilocus sequence typing (MLST). The isolates were assigned to 29 clonal complexes and singleton sequence types (CC1, CC5, CC6, CC7, CC8, CC9, CC12, CC15, CC22, CC25, CC30, CC49, CC59, CC88, CC97, CC130, CC133, CC398, ST425, CC599, CC692, CC707, ST890, CC1956, ST2425, CC2671, ST2691, CC2767 and ST2963), some of which (ST2425, ST2691, ST2963) were not described previously. Resistance rates in wildlife strains were rather low and mecA-MRSA isolates were rare (n = 6). mecC-MRSA (n = 8) were identified from a fox, a fallow deer, hares and hedgehogs. The common cattle-associated lineages CC479 and CC705 were not detected in wildlife in the present study while, in contrast, a third common cattle lineage, CC97, was found to be common among cervids. No Staphylococcus argenteus or Staphylococcus schweitzeri-like isolates were found. Systematic studies are required to monitor the possible transmission of human- and livestock-associated S. aureus/MRSA to wildlife and vice versa as well as the possible transmission, by unprotected contact to animals. The prevalence of S. aureus/MRSA in wildlife as well as its population structures in different wildlife host species warrants further investigation.

Presence and distribution of Macrolides-Lincosamide-Streptogramin resistance genes and potential indicator ARGs in the university ponds in Guangzhou, China

This study aimed to determine the occurrence, abundance, and variation of seven Macrolides-Lincosamide-Streptogramin (MLS) resistance genes (ereB, ermA, ermB, ermF, mefA, vatB, mphA) and six potential indicator ARGs (tet (B), sul1, qnrS, fexA, IntI1, ermB) from three ponds at university by quantitative PCR and assess the impacts on the surroundings. Solid samples (fish feces, soil and sediment) and water samples were tested. All the genes were found at low levels in soil samples. For the MLS resistance genes, only two MLS genes (ermB, ermF) were detected in all samples and significant correlations between ermB and Σ MLS (R = 0.91 in solid samples; R = 0.86 in water samples, p < 0.01) were found. For the potential indicators, intl1 and sul1 were present at high levels in the three different ponds while the other genes showed varying levels. These findings show that the ermB gene can probably be served as an indicator to evaluate the overall level of MLS resistance genes. The fairly low abundance of all the tested resistance genes in soil samples and the moderate levels in other samples suggests that the university ponds kept a good state and did not have a significant impact on their surroundings.

Interspecies spread of Staphylococcus aureus clones among companion animals and human close contacts in a veterinary teaching hospital. A cross-sectional study in Greece

Staphylococcus aureus and methicillin-resistant S. aureus (MRSA) prevalence among companion animals and veterinary personnel (VP) was investigated. Strains' molecular characteristics were evaluated in order to assess S. aureus transmission. Specimens (224) from colonized and infected sites of 102 animals (92 dogs, 10 cats) and 18 VP were collected during 2012 and 2013. Antibiotic susceptibility was performed by the disk diffusion method and Etest. mecA, mecC, tst (toxic shock syndrome toxin) and lukF/lukS-PV (Panton-Valentine leukocidin, PVL) genes were investigated by PCR. Genotypes were identified by Multi Locus Sequence Typing (MLST), Staphylococcal Cassette Chromosome mec (SCCmec), accessory gene regulator group (agr), spa and Pulsed Field Gel Electrophoresis (PFGE). S. aureus prevalence among pets and VP was 36.3% (37/102) and 38.9% (7/18), respectively. Younger companion animals, those living in rural areas, having a disease upon admission or Coagulase-negative staphylococci co-carriage showed significantly higher prevalence of S. aureus isolation (p<0.05). Twenty-six pets and five VP carried PVL-positive S. aureus. In total, 60 S. aureus strains were recovered (53 from pets, seven from VP) of which 16 were MRSA (26.7%), 12 mecA- and four mecC-positive. MRSA showed higher resistance rates against other antimicrobials as compared to methicillin-susceptible ones. Strains were classified by MLST in 13 STs, with the predominance of ST80 and ST15. In MRSA, SCCmec types II, IV and XI were identified. The most frequent spa types were t5559 and t7558. Fifty-six strains were classified into 15 PFGE types. Comparison of genetic markers shows that identical or very similar strains disseminate among animals and VP. Companion animals harbor PVL-positive clones constituting a possible source for transmission to humans.

Methicillin-resistant Staphylococcus aureus colonization and infection risks from companion animals: current perspectives

Methicillin-resistant Staphylococcus aureus (MRSA) remains one of the most virulent human pathogens and has also recently been recognized as such in the veterinary settings. Companion animals, including dogs, cats, horses, small exotic animals, wildlife animals, and livestock, may constitute a reservoir for MRSA transmission to humans and vice versa. The evolution, emergence, and risk factors for MRSA transmission among colonized or infected animals are reviewed in the present paper, and infection control practices are discussed.

Livestock-Associated MRSA: The Impact on Humans

During the past 25 years an increase in the prevalence of methicillin-resistant Staphylococcus aureus (HA-MRSA) was recorded worldwide. Additionally, MRSA infections may occur outside and independent of hospitals, caused by community associated MRSA (CA-MRSA). In Germany, we found that at least 10% of these sporadic infections are due to livestock-associated MRSA (LA-MRSA), which is initially associated with livestock. The majority of these MRSA cases are attributed to clonal complex CC398. LA-MRSA CC398 colonizes the animals asymptomatically in about half of conventional pig farms. For about 77%-86% of humans with occupational exposure to pigs, nasal carriage has been reported; it can be lost when exposure is interrupted. Among family members living at the same farms, only 4%-5% are colonized. Spread beyond this group of people is less frequent. The prevalence of LA-MRSA in livestock seems to be influenced by farm size, farming systems, usage of disinfectants, and in-feed zinc. LA-MRSA CC398 is able to cause the same kind of infections in humans as S. aureus and MRSA in general. It can be introduced to hospitals and cause nosocomial infections such as postoperative surgical site infections, ventilator associated pneumonia, septicemia, and infections after joint replacement. For this reason, screening for MRSA colonization at hospital admittance is recommended for farmers and veterinarians with livestock contacts. Intrahospital dissemination, typical for HA-MRSA in the absence of sufficient hygiene, has only rarely been observed for LA-MRSA to date. The proportion of LA-MRSA among all MRSA from nosocomial infections is about 3% across Germany. In geographical areas with a comparatively high density of conventional farms, LA-MRSA accounts for up to 10% of MRSA from septicemia and 15% of MRSA from wound infections. As known from comparative genome analysis, LA-MRSA has evolved from human-adapted methicillin-susceptible S. aureus, and the jump to livestock was obviously associated with several genetic changes. Reversion of the genetic changes and readaptation to humans bears a potential health risk and requires tight surveillance. Although most LA-MRSA (>80%) is resistant to several antibiotics, there are still sufficient treatment options.

Mini-review: Epidemiology and zoonotic potential of multiresistant bacteria and Clostridium difficile in livestock and food

AIM

Information on the epidemiology of multiresistant bacteria (MRB) with zoonotic potential is growing but still remains quite incomplete. This narrative mini-review provides a general overview of the epidemiology of the most important zoonotic MRB in cattle, swine and poultry in Europe.

METHODS

A literature search was conducted mainly on the PubMed website including articles published until April 2012.

RESULTS

Livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) especially poses a zoonotic risk to people working in close contact with livestock. These people may become carriers themselves and the hazard of transmission into health-care facilities needs surveillance. Extended-spectrum beta-lactamases (ESBL) producing bacteria are widely spread in both humans and livestock, sharing similar genotypes, especially of the CTX-M-group, which makes a zoonotic transfer very likely. Identical strains of vancomycin-resistant enterococci (VRE) were found both in humans and animals, after ingestion of animal strains transient colonization of the human gut may be possible. Only a few data are available on the transmission of methicillin-resistant coagulase-negative staphylococci (MR-CoNS) between humans and animals. Direct contact to colonized animals may be a risk factor as well as the exchange of resistance genes between human and animal staphylococci. Clostridium difficile (C. difficile) ribotype 078 emerges in livestock and humans and a zoonotic transmission seems probable as genotypes and diseases resemble each other.

CONCLUSION

All discussed MRB and C. difficile are important nosocomial agents which also occur in livestock and were found in foods of animal origin. Further analysis is needed to reveal the exact transmission routes and to perform a reliable risk assessment.

Risk factors for MRSA infection in companion animals: results from a case-control study within Germany

Increasing numbers of companion animals suffering from infections with methicillin-resistant Staphylococcus aureus (MRSA) have been reported in the recent past. These infections are of particular concern because of the limited treatment options for MRSA and their transferability to humans. Since MRSA lineages isolated from infected companion animals often mirror typical human epidemic strains circulating in the same region, successful strategies to combat MRSA need strong and coordinated efforts from both, the human and the veterinary field according to the "One Health" concept. Hence, to identify potential risk factors related to MRSA infections in dogs, cats and horses, a case-control study was conducted, including data on 106 MRSA-infected animal patients as cases and 102 MSSA-infected animals as controls, originating from 155 different veterinary settings within Germany. Demographic data on animal patients, patient history and administration of antibiotics as well as practice/clinic specific parameters were assessed as putative risk factors. Multivariable logistic regression identified the following variables as risk factors for MRSA infection compared to MSSA infection: number of employees working at the veterinary setting (n>10; p<0.001), antibiotic treatment prior to sampling (systemic: p=0.002; local: p=0.049, both: p=0.011) and surgical site infection (p<0.001). Spa typing revealed predominantly clonal complexes well-known for hospital-associated lineages spreading in human health-care settings in Germany (CC5 and CC22) for isolates of dog and cat origin. CC398-MRSA dominated among equine isolates, a CC that was described as a nosocomial pathogen in equine clinical settings before. The identified risk factors and genotyping results are in accordance with numerous study outcomes from the field of human medicine and point towards reasonable problems with nosocomial spread of MRSA, especially within companion animal veterinary clinics. To define targeted infection control strategies against nosocomial pathogens, it is important to accomplish intervention studies addressing routes of transmission in companion animal veterinary settings.

A shared population of epidemic methicillin-resistant Staphylococcus aureus 15 circulates in humans and companion animals

Methicillin-resistant Staphylococcus aureus (MRSA) is a global human health problem causing infections in both hospitals and the community. Companion animals, such as cats, dogs, and horses, are also frequently colonized by MRSA and can become infected. We sequenced the genomes of 46 multilocus sequence type (ST) 22 MRSA isolates from cats and dogs in the United Kingdom and compared these to an extensive population framework of human isolates from the same lineage. Phylogenomic analyses showed that all companion animal isolates were interspersed throughout the epidemic MRSA-15 (EMRSA-15) pandemic clade and clustered with human isolates from the United Kingdom, with human isolates basal to those from companion animals, suggesting a human source for isolates infecting companion animals. A number of isolates from the same veterinary hospital clustered together, suggesting that as in human hospitals, EMRSA-15 isolates are readily transmitted in the veterinary hospital setting. Genome-wide association analysis did not identify any host-specific single nucleotide polymorphisms (SNPs) or virulence factors. However, isolates from companion animals were significantly less likely to harbor a plasmid encoding erythromycin resistance. When this plasmid was present in animal-associated isolates, it was more likely to contain mutations mediating resistance to clindamycin. This finding is consistent with the low levels of erythromycin and high levels of clindamycin used in veterinary medicine in the United Kingdom. This study furthers the “one health” view of infectious diseases that the pathogen pool of human and animal populations are intrinsically linked and provides evidence that antibiotic usage in animal medicine is shaping the population of a major human pathogen.

Methicillin-resistant Staphylococcus aureus (MRSA) is major problem in human medicine. Companion animals, such as cats, dogs, and horses, can also become colonized and infected by MRSA. Here, we demonstrate that a shared population of an important and globally disseminated lineage of MRSA can infect both humans and companion animals without undergoing host adaptation. This suggests that companion animals might act as a reservoir for human infections. We also show that the isolates from companion animals have differences in the presence of certain antibiotic resistance genes. This study furthers the “one health” view of infectious diseases by demonstrating that the pool of MRSA isolates in the human and animal populations are shared and highlights how different antibiotic usage patterns between human and veterinary medicine can shape the population of bacterial pathogens.

Species diversity and antibiotic resistance properties of Staphylococcus of farm animal origin in Nkonkobe Municipality, South Africa

The occurrence and antibiotic susceptibility profile of Staphylococcus isolates of healthy farm animal origin in Nkonkobe Municipality as well as the prevalence of putative antibiotic resistance genes were investigated using phenotypic and molecular methods. A total of 120 Staphylococcus isolates were isolated from 150 animal samples and consisted of Staphylococcus haemolyticus (30 %) and Staphylococcus aureus (23.3 %) from pig, Staphylococcus capitis (15 %) from goat, S. haemolyticus (5 %) and Staphylococcus xylosus (15 %) from cattle, and other staphylococci (11.7 %) from dead chicken and pigs. Besides this, the presence of these isolates was observed from the animal dung, showing that the organisms are shed to the environment. About 23.3 % of these isolates were coagulase-positive and 76.7 % were coagulase-negative Staphylococcus. Between 75 and 100 % of the isolates were resistant to penicillin G, tetracycline, sulfamethoxazole, and nalidixic acid; about 38 % were methicillin-resistant staphylococci, including 12.6 % methicillin-resistant S. aureus from pigs. In total, 12 % of all isolates were vancomycin resistant. Also, 12 % of the isolates were erythromycin resistant, while 40.2 % were resistant to ceftazidime. Only the genes mecA and mphC could be confirmed, whereas the genes vanA, vanB, ermA, ermB, and ermC could not be detected. The high phenotypic antibiotic resistance and the presence of some associated resistance genes is a potential threat to public health and suggest the animals to be important reservoirs of antibiotic resistance determinants in the environment.

Alarming proportions of methicillin-resistant Staphylococcus aureus (MRSA) in wound samples from companion animals, Germany 2010-2012

Staphylococcus (S.) aureus is an important cause of wound infections in companion animals, and infections with methicillin-resistant S. aureus (MRSA) are of particular concern due to limited treatment options and their zoonotic potential. However, comparable epidemiological data on MRSA infections in dogs, cats and horses is scarce, also limiting the knowledge about possible links to MRSA isolates from human populations. To gain more knowledge about the occurrence and genotypic variation of MRSA among wound swabs of companion animal origin in Germany we performed a survey (2010–2012) including 5,229 samples from 1,170 veterinary practices. S. aureus was identified in 201 (5.8%) canine, 140 (12.2%) feline and 138 (22.8%) equine swabs from a total of 3,479 canine, 1,146 feline and 604 equine wounds, respectively. High MRSA rates were identified with 62.7%, 46.4% and 41.3% in S. aureus of canine, feline and equine origin, respectively. Further genotyping including spa typing and multilocus sequence typing (MLST) revealed a comparable distribution of spa types among canine and feline MRSA with CC22 (47.6%; 49.2%) and CC5 (30.2%; 29.2%) as predominant lineages followed by CC398 (13.5%; 7.7%) and CC8 (4.0%; 9.2%). In contrast, the majority of equine MRSA belonged to CC398 (87.7%). Our data highlight the importance of S. aureus and MRSA as a cause of wound infections, particularly in cats and horses in Germany. While “human-associated” MRSA lineages were most common in dogs and cats, a remarkable number of CC398-MRSA was detected in horses, indicating a replacement of CC8-MRSA as the predominant lineage within horses in Germany. These data enforce further longitudinal epidemiological approaches to examine the diversity and temporal relatedness of MRSA populations in humans and animals to assess probable sources of MRSA infections. This would enable a sound risk assessment and establishment of intervention strategies to limit the additional spread of MRSA.

Incidence and characterisation of methicillin-resistant Staphylococcus aureus (MRSA) from nasal colonisation in participants attending a cattle veterinary conference in the UK

We sought to determine the prevalence of nasal colonisation with methicillin-resistant Staphylococcus aureus among cattle veterinarians in the UK. There was particular interest in examining the frequency of colonisation with MRSA harbouring mecC, as strains with this mecA homologue were originally identified in bovine milk and may represent a zoonotic risk to those in contact with dairy livestock. Three hundred and seven delegates at the British Cattle Veterinarian Association (BCVA) Congress 2011 in Southport, UK were screening for nasal colonisation with MRSA. Isolates were characterised by whole genome sequencing and antimicrobial susceptibility testing. Eight out of three hundred and seven delegates (2.6%) were positive for nasal colonisation with MRSA. All strains were positive for mecA and none possessed mecC. The time since a delegate's last visit to a farm was significantly shorter in the MRSA-positive group than in MRSA-negative counterparts. BCVA delegates have an increased risk of MRSA colonisation compared to the general population but their frequency of colonisation is lower than that reported from other types of veterinarian conference, and from that seen in human healthcare workers. The results indicate that recent visitation to a farm is a risk factor for MRSA colonisation and that mecC-MRSA are rare among BCVA delegates (<1% based on sample size). Contact with livestock, including dairy cattle, may still be a risk factor for human colonisation with mecC-MRSA but occurs at a rate below the lower limit of detection available in this study.

Clonally related methicillin-resistant Staphylococcus aureus isolated from short-finned pilot whales (Globicephala macrorhynchus), human volunteers, and a bayfront cetacean rehabilitation facility

In May of 2011, a live mass stranding of 26 short-finned pilot whales (Globicephala macrorhynchus) occurred in the lower Florida Keys. Five surviving whales were transferred from the original stranding site to a nearby marine mammal rehabilitation facility where they were constantly attended to by a team of volunteers. Bacteria cultured during the routine clinical care of the whales and necropsy of a deceased whale included methicillin-sensitive and methicillin-resistant Staphylococcus aureus (MSSA and MRSA). In order to investigate potential sources or reservoirs of MSSA and MRSA, samples were obtained from human volunteers, whales, seawater, and sand from multiple sites at the facility, nearby recreational beaches, and a canal. Samples were collected on 3 days. The second collection day was 2 weeks after the first, and the third collection day was 2 months after the last animal was removed from the facility. MRSA and MSSA were isolated on each day from the facility when animals and volunteers were present. MSSA was found at an adjacent beach on all three collection days. Isolates were characterized by utilizing a combination of quantitative real-time PCR to determine the presence of mecA and genes associated with virulence, staphylococcal protein A typing, staphylococcal cassette chromosome mec typing, multilocus sequence typing, and pulsed field gel electrophoresis (PFGE). Using these methods, clonally related MRSA were isolated from multiple environmental locations as well as from humans and animals. Non-identical but genetically similar MSSA and MRSA were also identified from distinct sources within this sample pool. PFGE indicated that the majority of MRSA isolates were clonally related to the prototype human strain USA300. These studies support the notion that S. aureus may be shed into an environment by humans or pilot whales and subsequently colonize or infect exposed new hosts.

Methicillin-resistant staphylococci: implications for our food supply?

Food-borne intoxication, caused by heat-stable enterotoxins produced by Staphylococcus aureus, causes over 240,000 cases of food-borne illness in the United States annually. Other staphylococci commonly associated with animals may also produce these enterotoxins. Foods may be contaminated by infected food handlers during slaughter and processing of livestock or by cross-contamination during food preparation. S. aureus also causes a variety of mild to severe skin and soft tissue infections in humans and other animals. Antibiotic resistance is common in staphylococci. Hospital-associated (HA) S. aureus are resistant to numerous antibiotics, with methicillin-resistant S. aureus (MRSA) presenting significant challenges in health care facilities for over 40 years. During the mid-1990s new human MRSA strains developed outside of hospitals and were termed community-associated (CA). A few years later, MRSA was isolated from horses and methicillin resistance was detected in Staphylococcus intermedius/pseudintermedius from dogs and cats. In 2003, a livestock-associated (LA) MRSA strain was first detected in swine. These methicillin-resistant staphylococci pose additional food safety and occupational health concerns. MRSA has been detected in a small percentage of retail meat and raw milk samples indicating a potential risk for food-borne transmission of MRSA. Persons working with animals or handling meat products may be at increased risk for antibiotic-resistant infections. This review discusses the scope of the problem of methicillin-resistant staphylococci and some strategies for control of these bacteria and prevention of illness.

Sequence type 398 meticillin-resistant Staphylococcus aureus infection in a pet rabbit

BACKGROUND

Meticillin-resistant Staphylococcus aureus (MRSA) is a frequent pathogen of humans and many animal species, and has become established as a veterinary pathogen.

CASE REPORT

In this case report we describe an MRSA infection in a dwarf rabbit, treatment of the infection and, subsequently, the genetic analysis of the isolated strain. The pet rabbit was presented to an animal hospital due to recurrent swellings on the head and on the neck. Bacteriological examination yielded Staphylococcus aureus, which was resistant to β-lactam antibiotics. The isolate was confirmed as an MRSA by mecA PCR, Panton-Valentine leukocidin (PVL) negative, and typed as multilocus sequence type (ST)398/staphylococcal protein A (spa) type t011/staphylococcal cassette chromosome mec (SCCmec) type SCCmecIVa. The rabbit was treated with rifampicin for 2 weeks. After 2.5 weeks the rabbit was clinically normal and control swabs were negative for MRSA.

CONCLUSIONS AND CLINICAL IMPORTANCE

This study is the first to report MRSA in a rabbit in Austria. This study contributes to the growing evidence that MRSA ST398 could be isolated from a variety of animals.

Working across the veterinary and human health sectors

Antibiotics are widely used in human and veterinary medicine for the prevention and treatment of infectious diseases. This practice has led to the emergence of antimicrobial-resistant bacteria in both humans and animals. The potential role that animals, particularly livestock, might play as potential reservoirs of antibiotic resistance genes has been recognized, and it is currently a cause of public health concern. The impact of animal and human antibiotic usage on the emergence and persistence of resistant bacteria and the precise transfer pathways for resistance genes between humans and animals are not currently fully understood. As part of the remit of the UK Advisory Committee on Antimicrobial Resistance and Healthcare-Associated Infection (ARHAI), two main areas were addressed, namely methicillin-resistant Staphylococcus aureus (MRSA) and multidrug-resistant Gram-negative bacteria, where both the human and veterinary health sectors share interests. We review the current knowledge of MRSA and resistant Gram-negative bacteria, and provide guidance on occupational risks for veterinary healthcare workers relating to animals infected or colonized with MRSA. Findings and recommendations for further work across disciplines and future research in multidrug-resistant Gram-negative bacteria are also presented. Working collaboratively across disciplines is essential in order to better understand and challenge an important human and animal health problem: antimicrobial resistance.