First report of identification of livestock-associated MRSA ST9 in retail meat in England

Abstract

Sixty percent of all meat consumed in the UK is imported from European countries where there have been increasing reports of methicillin-resistant Staphylococcus aureus (MRSA) identified in food-producing animals, but rarely from such animals in the UK. Thirty samples each of raw chicken, pork and beef, sourced in England, were collected from retail outlets in Greater Manchester. MRSA was recovered from three chicken samples and one each of pork and beef, all from prepackaged supermarket meat. Four isolates were identified as representatives of the most common human healthcare-associated MRSA clone in the UK [EMRSA-15, spa type t032, belonging to multilocus sequence type clonal complex 22 (MLST-CC22)], suggesting contamination from human source(s) during meat processing. The fifth isolate (from chicken) was multiply-resistant (including oxacillin, ciprofloxacin, erythromycin, clindamycin and tetracycline), identified as ST9-SCCmecIV, spa type t1939 and lacked the immune evasion cluster, a characteristic of livestock-associated strains. This lineage has been identified previously from animals and meat products in Asia and mainland Europe but not the UK.

Detection and molecular characterization of Livestock-Associated MRSA in raw meat on retail sale in North West England

“…In a separate study in North West England in 2011, CC398 LA‐MRSA was not detected in 30 samples each of chicken, pork and beef, but a different LA‐MRSA strain belonging to CC9 (a lineage predominant in Asia) was recovered from one (3·3%) raw chicken sample (Dhup et al . ). The current study was carried out in the same geographic region as the latter, but 4 years later and detected a higher LA‐MRSA rate in chickens of 8%.…”

“…Similarly, there have been scant reports of LA‐MRSA from raw meat at retail sale in the UK: one survey described the isolation of CC398 LA‐MRSA from 2 of 52 samples of pork; another reported LA‐MRSA belonging to a lineage predominant in Asia (CC9) from one of 30 chicken meat samples (Dhup et al . ; Hadjirin et al . ).…”

Livestock-Associated MRSA and Its Current Evolution

“…The first time an ST9 strain was found in Europe was in 2008, in Italy, although the most prevalent ST was the typical European ST398 [3]. Since then, LA-MRSA ST9 isolates have been detected in pigs [48] and poultry [69] from Germany and in retail meat from the UK [70]. However, a recent study shows that LA-MRSA ST9 was present in some European countries before the emergence of CC398 [71].…”

“…According to EspinosaGongora et al [71], the first European CC9 isolates were discovered between 1973 and 2009 and carried diverse spa types (t337, t526, t899, t1334, t2498, t3446). The European isolates found recently carry mainly spa types t337 [48], t1430 [48,69], t1939 [70], and t4794 [3]. CC9 Asian isolates carry diverse spa types, such as t899, t4358, and t337 [17].…”

Veterinary medicines update

“…Since then, findings have been reported in poultry (Anon 2013) and pigs (Hartley and others 2014, Hall and others 2015) as well as in unpasteurised milk samples (Paterson and others 2012), pork (Hadjirin and others 2015) and chicken meat (Dhup and others 2015). LA-MRSA is no longer considered to be a novel finding in the UK, but while the number of isolates identified remains low, Defra's Antimicrobial Resistance Coordination Group (DARC) believes that knowledge of additional findings may be of interest to those who work with livestock.…”