Livestock-Associated methicillin resistant Staphylococcus aureus in animals and humans

ArticleinInternational journal of medical microbiology: IJMM 301(8):630-4 · December 2011with23 Reads
DOI: 10.1016/j.ijmm.2011.09.004 · Source: PubMed
Since 2004 MRSA emerged in animals, particularly in pigs and veal calves. This new MRSA variant was since its first appearance referred to as Livestock Associated-MRSA (LA-MRSA). In Europe and Northern America, LA-MRSA belongs predominantly to clonal complex (CC) 398 whereas in Asia ST9 seems to be dominant in pigs. Persons in direct contact with LA-MRSA-positive animals have an increased risk of becoming MRSA positive. The risk of carriage is mainly related with the intensity of animal contact and with MRSA prevalence among animals on the farm. In contrast with its success in animals, it seemed that MRSA CC398 is a poor persistent colonizer in humans. MRSA ST398 can, however, cause serious (invasive) infections and outbreaks, although, only incidentally reported so far. Farm hygiene and antimicrobial use contributed to MRSA occurrence in animals. Therefore these two determinants should in principle be incorporated into MRSA-control programmes in animal production. Like any other microorganism, LA-MRSA is expected to be able to adapt to new hosts and may change over time in the potential to colonize and to produce toxins. Also, the current circulating clone CC398 may be replaced by another clone in Western countries or emerge in countries where this clone is currently low-prevalent. Ongoing MRSA surveillance in humans and animals is needed to detect changes in epidemiology and to implement effective control measures.
    • Methicillin resistant Staphylococcus aureus (MRSA) first emerged as an important cause of hospital acquired infections in humans primarily during the 1980 s , and ten years later had spread outside the hospital setting also causing community acquired infections (Moellering, 2012). During the last decade MRSA has also emerged among animals and particularly among farm animals where occurrence is foremost due to asymptomatic carriage of specific livestock adapted clones (Graveland et al., 2011). Resistance to methicillin and other beta-lactams in MRSA is encoded by mec-genes of which mecA is the predominant variant.
    [Show abstract] [Hide abstract] ABSTRACT: We investigated the occurrence of mecC-MRSA in wild hedgehogs (Erinaceus europaeus) in Sweden and characterized the obtained isolates. Samples from 55 hedgehogs from five counties of Sweden were cultivated selectively for MRSA and putative isolates were confirmed by real-time PCR detecting mecA, mecC, nuc and PVL genes. mecC-MRSA was confirmed in 35 (64%) animals from three geographically separated counties. Confirmed isolates were spa-typed and tested for antimicrobial susceptibility by broth microdilution. Eight different spa-types were identified (t843, t978, t3391, t9111, t10751, t10893, t11015, t15312) of which t843 (49%) was the most common. The spa-types t843, t3391 and t978 were found in isolates from two counties. The study shows that mecC-MRSA is common in wild hedgehogs in two counties of Sweden but occurs in hedgehogs also in other parts of the country. Our findings suggest that hedgehogs could be a reservoir for mecC-MRSA. In addition, similar spa-types of isolates from hedgehogs and isolates previously described in domesticated animals and in humans indicates transfer between these populations.
    Full-text · Article · Jun 2017 · Infection, genetics and evolution: journal of molecular epidemiology and evolutionary genetics in infectious diseases
    • Further, reports of livestockassociated MRSA (LA-MRSA) ST398 causing mastitis have created additional public health concerns regarding production animals, including dairy cows, as a source of antimicrobialresistant bacteria which can spill-over into humans (Monecke et al., 2007;Feßler et al., 2010;Fitzgerald, 2012;Tenhagen et al., 2014). It is now commonly accepted that persons working in close contact with animals are at a higher risk of being colonized or even infected with zoonotic bacteria carried by animals than individuals who do not interact with animals (Graveland et al., 2011). It is therefore recommended that surveillance at the interface between human and animal hosts is monitored in order to detect any potential, emerging human health risks (Fitzgerald, 2012;Cuny et al., 2015).
    [Show abstract] [Hide abstract] ABSTRACT: Staphylococcus aureus is one of the most common etiological agents of contagious bovine mastitis worldwide. The purpose of this study was to genetically characterize a collection of S. aureus isolates (bovine = 146, human = 12) recovered from cases of bovine mastitis and nasal swabs of close human contacts in the dairy environment. Isolates were screened for a combination of clinically significant antimicrobial and virulence gene markers whilst the molecular epidemiology of these isolates and possible inter-species host transmission was investigated using a combination of genotyping techniques. None of the isolates under evaluation tested positive for methicillin or vancomycin resistance encoding genes. Twenty seven percent of the bovine S. aureus isolates tested positive for one or more of the pyrogenic toxin superantigen (PTSAg) genes with the sec and sell genes predominating. Comparatively, 83% of the human S. aureus isolates tested positive for one or more PTSAg genes with a greater variety of genes being detected. Genomic DNA macrorestriction followed by pulsed-field gel electrophoresis (PFGE) of the bovine isolates generated 58 electrophoretic patterns which grouped into 10 pulsotypes at an 80% similarity level. The majority of the bovine isolates, 93.2% (136/146), clustered into four major pulsotypes. Seven sequence types (ST) were identified among the representative bovine S. aureus isolates genotyped, including: ST8 (CC8), ST97 (CC97), ST351 (CC705), ST352 (CC97), ST508 (CC45), ST2992 (CC97) and a novel sequence type, ST3538 (CC97). Based on PFGE analysis, greater genetic diversity was observed among the human S. aureus isolates. Bovine and human isolates from three sampling sites clustered together and were genotypically indistinguishable. Two of the isolates, ST97 and ST352 belong to the common bovine lineage CC97, and their isolation from close human contacts suggests zoonotic transfer. In the context of this study, the third isolate, ST8 (CC8), is believed to be a human clone which has transferred to a dairy cow and has subsequently caused mastitis. The detection of indistinguishable S. aureus isolates from bovine and human hosts at three of the sampling sites is suggestive of bacterial transmission and supports the need for vigilant monitoring of staphylococcal populations at the human-animal interface.
    Full-text · Article · Apr 2017
    • In an interesting report from the Netherlands, it was shown that farm visitors were positive for CC398 MRSA directly after a farm visit but tested MRSA negative after 24 h [19, 41]. These and other studies indicate that CC398 appears to be frequently shared between animals and humans and is capable of causing infections in both species [25, 70, 164]. Transmission of MRSA between animals and humans is not new, but the MRSA isolates, in most cases, represent an initial human-to-animal transmission [24, 49, 165, 166].
    Chapter · Mar 2017 · Infection, genetics and evolution: journal of molecular epidemiology and evolutionary genetics in infectious diseases
    • Apart from HA- MRSA and CA-MRSA, livestock-associated MRSA (LA-MRSA) is persistent in colonizing pigs and calves [5]. A number of cases have been reported on LA-MRSA carriers with zoonotic pneumonia, endocarditis, and necrotizing fasciitis [6]. Due to carriage of the mec gene (mecA, mecB, and mecC) which encodes a novel specific penicillin-binding protein (PBP2a), MRSA expresses resistance to b-lactam antibiotics [7].
    [Show abstract] [Hide abstract] ABSTRACT: Considered to be a potential “superbug”, methicillin-resistant Staphylococcus aureus (MRSA) has been one of the major recent infectious pathogens and thus poses a challenge to hospital infection control. The mobile genetic element staphylococcal chromosomal cassette mec (SCCmec) carries both the mecA or mecC gene, encoding for a novel specific penicillin-binding protein (PBP2a), and site-specific recombinase genes ccrAB or/and ccrC. In MRSA, the acquisition of SCCmec leads to the resistance to the β-lactam antibiotics. As SCCmec plays a core role in the antimicrobial resistance characteristics, molecular epidemiology and evolution of MRSA, a thorough summary and comprehensive understanding of the prevalence and structural characteristics of SCCmec may aid in global surveillance, implementation and investigation on MRSA isolates, as well as further development of preventive and therapeutic approaches. Consequently, this review is aimed at describing the history, prevalence, types and subtypes, and current typing methods of SCCmec, with the focus on the typical structures of the SCCmec cassette.
    Full-text · Article · Nov 2016
    • Due to the presence of a restriction/methylation system, the strains are non-typeable with standard PFGE using SmaI digestion. ST398 is a typical livestockassociated type (Graveland et al., 2011), previous studies show
    [Show abstract] [Hide abstract] ABSTRACT: Staphylococcus aureus is a globally important human pathogen, especially among children and immunocompromised patients. The emergence and spread of community-associated methicillin-resistant S. aureus (CA-MRSA) has become a serious public health problem worldwide. The aim of this study was to investigate the prevalence, molecular characteristics and virulence profiles of CA-MRSA infections from pediatric patients in a university hospital in Shanghai, China. A total of 80 CA-MRSA isolates were collected from July 2012 to December 2013 in Shanghai Children's Medical Center and analyzed by multilocus sequence typing, staphylococcus chromosomal cassette mec (SCCmec) typing, and spa typing. The detection of Panton-Valentine Leukocidin (pvl), superantigenic and exfoliative toxins, and adhesin genes was also performed. Overall, 16 distinct sequence types (STs) were identified among the 80 isolates. Among them, ST59 was found to be the most prevalent, followed by ST398 (11.3%, 9/80) and ST88 (8.8%, 7/80). SCCmec types IV and V were observed, at 60 and 40%, respectively. Thirty spa types were identified, spa t437 (23.8%) was the most predominant type. All 80 isolates exhibited carriage of at least four virulence genes. Thirty-four (42.5%, 34/80) isolates harbored ≥10 tested virulence genes. Adhesion genes were present in most of the MRSA isolates, including the following: icaA (100%), clfA (100%), sdrC (95%), and sdrE (63.8%). The prevalence of pvl gene was 20%, and multidrug resistance was observed in 36% of all strains. In addition, ST59-MRSA-IV with t437 accounted for 21.3% of occurrences, making it the most prevalent clone. Isolates that were carriers of toxin genes, and hla (100%) and hlg (87.5%) were the most frequent. In conclusion, simultaneous carriage of multiple virulence genes and genetically considerable diversity were very common among CA-MRSA from pediatric patients in Shanghai. ST59-MRSA-IV with t437 was still the most predominant type. The combination of virulence gene profiles and antibiotic resistance may help ST59 to be successfully spread among children.
    Full-text · Article · Nov 2016
    • Staphylococcus aureus can cause a broad range of infections both in humans and animals. In industrialized countries, wildlife and livestock animals are an important reservoir for methicillin resistant S. aureus (MRSA) infections in humans (Graveland et al., 2011). To test if this is also true for developing regions, only few studies have been performed in African animals which detected no MRSA in wildlife and very low MRSA colonization rates in domestic pigs (10.5%) (Fall et al., 2012; Schaumburg et al., 2014 ).
    [Show abstract] [Hide abstract] ABSTRACT: The colonization of afro-tropical wildlife with Staphylococcus aureus and the derived clade Staphylococcus schweitzeri remains largely unknown. A reservoir in bats could be of importance since bats and humans share overlapping habitats. In addition, bats are food sources in some African regions and can be the cause of zoonotic diseases. Here, we present a cross-sectional survey employing pharyngeal swabs of captured and released bats (n = 133) in a forest area of Gabon. We detected low colonization rates of S. aureus (4–6%) and S. schweitzeri (4%) in two out of four species of fruit bats, namely Rousettus aegyptiacus and Micropteropus pusillus, but not in insectivorous bats. Multilocus sequence typing showed that S. aureus from Gabonese bats (ST2984, ST3259, ST3301, ST3302) were distinct from major African human associated clones (ST15, ST121, ST152). S. schweitzeri from bats (ST1697, ST1700) clustered with S. schweitzeri from other species (bats, monkeys) from Nigeria and Côte d'Ivoire.
    Full-text · Article · Nov 2016
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