Livestock-Associated MRSA and Its Current Evolution

Abstract

Livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) is a relatively recent phenomenon in veterinary medicine. Although in the beginning it was restricted to a single clonal complex (CC), CC398, it has expanded into several clonal complexes, and the diversity of subtypes in the clonal complexes is increasing also. The prevalence of each type is determined somewhat geographically; for instance, the most prevalent clonal complex in Europe is CC398, whereas in Asia, it is CC9. Although few data exist regarding North America, the situation appears to be mixed there. The SCCmec cassettes detected in LA-MRSA are limited mainly to SCCmec IVa and SCCmec V, although non-typeable cassettes and SCCmec type XI, containing mecC, also have been found.The source of the SCCmec in LA-MRSA was discovered to be animals. In searching from which bacteria the SCCmec cassettes in LA-MRSA have been transferred, the most obvious species to consider are the methicillin-resistant non-S. aureus staphylococci (MRNaS). However, very few data are available from those species in animals, and the data that do exist are not detailed enough to determine the origin. Nevertheless, similar cassettes were found in MRNaS, indicating a possible origin that needs to be investigated further.

Livestock-Associated Methicillin Resistant Staphylococcus aureus (LA-MRSA) Clonal Complex (CC) 398 Isolated from UK Animals belong to European Lineages

“…In 2005 (Voss et al, 2005) identified a new lineage of MRSA, sequence type (ST) 398 grouping within clonal complex (CC) 398 (http://saureus.mlst.net) associated with livestock and able to colonize humans. Following this, livestock associated (LA) MRSA; namely CC398 has been reported globally, in horses, cattle and poultry (Butaye et al, 2016). …”

“…In Europe, LA-MRSA has been widely reported from various countries in pigs, poultry and cattle (Butaye et al, 2016), with infrequent reports from the UK. The number of cases of LA-MRSA in farm animals in the UK is gradually increasing with recent reports from, horses, cattle, poultry, pigs, and pork meat products (Loeffler et al, 2009; Paterson et al, 2014).…”

Heavy metal and disinfectant resistance genes among livestock-associated methicillin-resistant Staphylococcus aureus isolates

“…Most of the livestock-associated (LA) MRSA in Europe belong to the clonal complex (CC) 398, although other CCs have also been described (Crombé et al, 2013;Butaye et al, 2016). The reason why LA-MRSA emerged is not fully understood.…”

“…The reason why LA-MRSA emerged is not fully understood. It has been suggested that tetracycline-resistance could have driven selection of MRSA CC398 (Crombé et al, 2013;Butaye et al, 2016).…”

Investigation of mecA gene, virulence traits and antibiotic resistance profiles in methicillin‐resistant Staphylococcus aureus isolates from dairy products

“…To date, MRSA, in relation with community‐acquired (CA‐MRSA) infections, has become one of the most important antimicrobial resistant pathogens worldwide (Doulgeraki, Ciccio, Ianieri, & Nychas, ). Livestock‐associated MRSA (LA‐MRSA) harboring the mec C gene has been implicated in bovine mastitis but has generally been considered nonpathogenic for human (Butaye, Argudin, & Smith, ). However, MRSA has two epidemiological variants.…”