MRSA carrying mecC in captive mara

mecC MRSA in Israel—genomic analysis, prevalence and global perspective

Background

MRSA is a major global healthcare problem. In 2011, a new mec variant designated mecC was described, presenting partial identity at the DNA level, thus undetectable by routine mecA PCR.

Objectives

Until now, no reliable information regarding mecC MRSA prevalence was available in Israel. In this study, to the best of our knowledge, we describe the first case of mecC MRSA in Israel, with focus on genomic analysis and global context.

Methods

The mecC MRSA isolate was analysed by WGS with focus on phylogeny, global contextualization, virulence and resistance genes. The strain was characterized by antibiotic susceptibility testing, spa typing and presence of mecA/C and pvl genes.

Results

An MRSA strain (SA10610), isolated from a urine sample of an 83-year old patient, was found negative for the mecA and pvl genes. The MLST and spa type were ST130 and t1736, respectively. SA10610 presented resistance to oxacillin, penicillin and cefoxitin, and susceptibility to all non-β-lactam agents tested. Phylogenetic comparison with a global dataset of 586 mecC MRSA genomes revealed substantial genomic divergence. The nearest genomic relatives were human and animal isolates from Denmark. A screen of 12 761 S. aureus isolates collected during 2011–18 in Israel indicated this is the only mecC-positive strain.

Conclusions

A high degree of genetic variability was found between the SA10610 strain and previously sequenced mecC MRSA isolated worldwide. The genomic and phylogenetic analysis suggest that mecC MRSA isolates have evolved independently rather than from a common ancestor.

Nocturnal Birds of Prey as Carriers of Staphylococcus aureus and Other Staphylococci: Diversity, Antimicrobial Resistance and Clonal Lineages

Owls are nocturnal predators that inhabit urbanized and farmlands. They are in direct contact with other animals, both livestock and small wild rodents that they mostly feed on. Staphylococci can be both commensal and pathogenic bacteria that are widespread across the various ecological niches. We aimed to isolate staphylococci from owls and to characterize their antimicrobial resistance, virulence factors and genetic lineages. Swab samples were collected from the throat and cloaca of 114 owls admitted to two rehabilitation centers in Portugal. The identification of staphylococci species was performed by MALDI-TOF. Staphylococci antimicrobial resistance and virulence genes were investigated by means of the disk diffusion method and PCR. Staphylococcus aureus isolates were characterized by MLST, agr and spa-typing. Of the tested animals, 66 isolates were recovered, including 10 different species of staphylococci, of which 25 were coagulase-positive (CoPS) and 41 were coagulase-negative (CoNS). Twenty-three S. aureus were isolated, of which one mecC-MRSA was identified. The isolates were mainly resistant to penicillin, aminoglycosides, clindamycin and tetracycline. mecC-MRSA belonged to ST1245 and spa-type t843 and the remaining S. aureus were ascribed to 12 STs and 15 spa types. A high diversity of clonal lineages was identified among the S. aureus isolated from wild owls. Owls feed mainly on small rodents often exposed to waste and anthropogenic sources, which may explain the moderate prevalence of S. aureus in these animals.

Molecular Epidemiology of Staphylococcus aureus Lineages in Wild Animals in Europe: A Review

Staphylococcus aureus is an opportunist pathogen that is responsible for numerous types of infections. S. aureus is known for its ability to easily acquire antibiotic resistance determinants. Methicillin-resistant S. aureus (MRSA) is a leading cause of infections both in humans and animals and is usually associated with a multidrug-resistant profile. MRSA dissemination is increasing due to its capability of establishing new reservoirs and has been found in humans, animals and the environment. Despite the fact that the information on the incidence of MRSA in the environment and, in particular, in wild animals, is scarce, some studies have reported the presence of these strains among wildlife with no direct contact with antibiotics. This shows a possible transmission between species and, consequently, a public health concern. The aim of this review is to better understand the distribution, prevalence and molecular lineages of MRSA in European free-living animals.

Staphylococcus aureus Epidemiology in Wildlife: A Systematic Review

Staphylococcus aureus is a common bacterial colonizer of humans and a variety of animal species. Many strains have zoonotic potential, moving between humans and animals, including livestock, pets, and wildlife. We examined publications reporting on S. aureus presence in a variety of wildlife species in order to more cohesively review distribution of strains and antibiotic resistance in wildlife. Fifty-one studies were included in the final qualitative synthesis. The most common types documented included ST398, ST425, ST1, ST133, ST130, and ST15. A mix of methicillin-resistant and methicillin-susceptible strains were noted. A number of molecular types were identified that were likely to be found in wildlife species, including those that are commonly found in humans or other animal species (including livestock). Additional research should include follow-up in geographic areas that are under-sampled in this study, which is dominated by European studies.

Methicillin-Resistant Staphylococcus aureus: Molecular Characterization, Evolution, and Epidemiology

Staphylococcus aureus, a major human pathogen, has a collection of virulence factors and the ability to acquire resistance to most antibiotics. This ability is further augmented by constant emergence of new clones, making S. aureus a "superbug." Clinical use of methicillin has led to the appearance of methicillin-resistant S. aureus (MRSA). The past few decades have witnessed the existence of new MRSA clones. Unlike traditional MRSA residing in hospitals, the new clones can invade community settings and infect people without predisposing risk factors. This evolution continues with the buildup of the MRSA reservoir in companion and food animals. This review focuses on imparting a better understanding of MRSA evolution and its molecular characterization and epidemiology. We first describe the origin of MRSA, with emphasis on the diverse nature of staphylococcal cassette chromosome mec (SCCmec). mecA and its new homologues (mecB, mecC, and mecD), SCCmec types (13 SCCmec types have been discovered to date), and their classification criteria are discussed. The review then describes various typing methods applied to study the molecular epidemiology and evolutionary nature of MRSA. Starting with the historical methods and continuing to the advanced whole-genome approaches, typing of collections of MRSA has shed light on the origin, spread, and evolutionary pathways of MRSA clones.

Characterization of Livestock-Associated Methicillin-Resistant Staphylococcus aureus CC398 and mecC-positive CC130 from Zoo Animals in the United Kingdom

Little is known about the characteristics and diseases associated with methicillin-resistant Staphylococcus aureus (MRSA) in nondomestic animals. Four presumptive MRSA isolates, obtained from clinical (n = 3) and surveillance specimens (n = 1) from dwarf (Helogale parvula) and yellow mongooses (Cynictis penicillata) from a United Kingdom zoo, were analyzed by PCR for detection of mecA and mecC-mediated methicillin resistance, and virulence genes. Isolates were genotyped by multilocus sequence typing (MLST) and staphylococcal cassette chromosome mec (SCCmec) and spa sequence typing. Three isolates, obtained from the dwarf mongooses, carried mecA, tetK, and fexA resistance and virulence genes (icaA, icaD, and sec) and were typed to SCCmec IVa, spa type t899, and clonal complex (CC) 398. The fourth MRSA isolate, obtained from the femoral bone marrow of a yellow mongoose showing postmortem findings consistent with septicemia, carried mecC and was oxacillin/cefoxitin susceptible, when tested at 37°C but showed a characteristic MRSA susceptibility profile at 25°C ± 2°C. Furthermore, this isolate exhibited a different genetic background (SCCmecXI/t843/CC130) and had biofilm-associated genes (bap, icaA, and icaD) and tetK tetracycline resistance genes. This work describes the first isolation of livestock-associated MRSA CC398 from two zoo mongoose species where it was associated with both clinical disease and colonization, and the first isolation of mecC MRSA from a zoo species in the United Kingdom. Both reports highlight the potential for zoo species to act as reservoirs for these zoonotic agents.

Bacteria from Animals as a Pool of Antimicrobial Resistance Genes

Antimicrobial agents are used in both veterinary and human medicine. The intensive use of antimicrobials in animals may promote the fixation of antimicrobial resistance genes in bacteria, which may be zoonotic or capable to transfer these genes to human-adapted pathogens or to human gut microbiota via direct contact, food or the environment. This review summarizes the current knowledge of the use of antimicrobial agents in animal health and explores the role of bacteria from animals as a pool of antimicrobial resistance genes for human bacteria. This review focused in relevant examples within the ESC(K)APE (Enterococcus faecium, Staphylococcus aureus, Clostridium difficile (Klebsiella pneumoniae), Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacteriaceae) group of bacterial pathogens that are the leading cause of nosocomial infections throughout the world.

Horses in Denmark Are a Reservoir of Diverse Clones of Methicillin-Resistant and -Susceptible Staphylococcus aureus

Denmark is a country with high prevalence of livestock-associated methicillin-resistant Staphylococcus aureus (MRSA) clonal complex (CC) 398 in pigs. Even though pig farming is regarded as the main source of human infection or colonization with MRSA CC398, 10-15% of the human cases appear not to be linked to pigs. Following the recent reports of MRSA CC398 in horses in other European countries and the lack of knowledge on S. aureus carriage in this animal species, we carried out a study to investigate whether horses constitute a reservoir of MRSA CC398 in Denmark, and to gain knowledge on the frequency and genetic diversity of S. aureus in horses, including both methicillin-resistant and -susceptible S. aureus (MSSA). Nasal swabs were collected from 401 horses originating from 74 farms, either at their farms or prior to admission to veterinary clinics. Following culture on selective media, species identification by MALDI-TOF MS and MRSA confirmation by standard PCR-based methods, S. aureus and MRSA were detected in 54 (13%) and 17 (4%) horses originating from 30 (40%) and 7 (9%) farms, respectively. Based on spa typing, MSSA differed genetically from MRSA isolates. The spa type prevalent among MSSA isolates was t127 (CC1), which was detected in 12 horses from 11 farms and represents the most common S. aureus clone isolated from human bacteremia cases in Denmark. Among the 17 MRSA carriers, 10 horses from three farms carried CC398 t011 harboring the immune evasion cluster (IEC), four horses from two farms carried IEC-negative CC398 t034, and three horses from two farms carried a mecC-positive MRSA lineage previously associated with wildlife and domestic ruminants (CC130 t528). Based on whole-genome phylogenetic analysis of the 14 MRSA CC398, t011 isolates belonged to the recently identified horse-adapted clone in Europe and were closely related to human t011 isolates from three Danish equine veterinarians, whereas t034 isolates belonged to pig-adapted clones. Our study confirms that horses carry an equine-specific clone of MRSA CC398 that can be transmitted to veterinary personnel, and reveals that these animals are exposed to MRSA and MSSA clones that are likely to originate from livestock and humans, respectively.

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.