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

Abstract

In recent years, there has been an increase in the number of livestock-associated methicillin resistant Staphylococcus aureus (LA-MRSA) clonal complex (CC) 398 recovered from S. aureus isolated animals in the UK. To determine possible origins of 12 LA-MRSA CC398 isolates collected after screening more than a thousand S. aureus animal isolates from the UK between 2013 and 2015, whole genome sequences (WGS) of CC398 European, including UK, and non-European isolates from diverse animal hosts were compared. Phylogenetic reconstruction applied to WGS data to assess genetic relatedness of all 89 isolates, clustered the 12 UK CC398 LA-MRSA within the European sub-lineages, although on different nodes; implicating multiple independent incursions into the UK, as opposed to a single introduction followed by clonal expansion. Three UK isolates from healthy pigs and one from turkey clustered within the cassette chromosome recombinases ccr C S. aureus protein A (spa)-type t011 European sub-lineage and three UK isolates from horses within the ccrA2B2 t011 European sub-lineage. The remaining UK isolates, mostly from pigs, clustered within the t034 European lineage. Presence of virulence, antimicrobial (AMR), heavy metal (HMR), and disinfectant (DR) resistance genes were determined using an in-house pipeline. Most, including UK isolates, harbored resistance genes to ≥3 antimicrobial classes in addition to β-lactams. HMR genes were detected in most European ccrC positive isolates, with >80% harboring czrC, encoding zinc and cadmium resistance; in contrast ~60% ccrC isolates within non-European lineages and 6% ccrA2B2 isolates showed this characteristic. The UK turkey MRSA isolate did not harbor φAVβ avian prophage genes (SAAV_2008 and SAAV_2009) present in US MSSA isolates from turkey and pigs. Absence of some of the major human-associated MRSA toxigenic and virulence genes in the UK LA-MRSA animal isolates was not unexpected. Therefore, we can conclude that the 12 UK LA-MRSA isolates collected in the past 2 years most likely represent separate incursions into the UK from other European countries. The presence of zinc and cadmium resistance in all nine food animal isolates (pig and poultry), which was absent from the 3 horse isolates may suggest heavy metal use/exposure has a possible role in selection of some MRSA.

Low prevalence of livestock‐associated methicillin‐resistantStaphylococcus aureusclonal complex 398 andmecCMRSA among human isolates in North‐West England

“…Phylogenetic analysis using cgMLST of all published, sequenced CC398 LA‐MRSA from the United Kingdom shows a diverse population which others have shown are related to mainland European isolates and is consistent with multiple introductions into the United Kingdom (Ward et al ; Sharma et al ). This current analysis is the largest collection of sequenced LA‐MRSA CC398 from the United Kingdom and indicates the close genetic linkage between a pair of human and turkey isolates which were both isolated in the east of England in 2013 and which are separated by 12 genome SNPs.…”

Molecular Characteristics of Staphylococcus aureus Causing Bovine Mastitis between 2014 and 2015

“…In European countries and in North America, CC398 was the overwhelmingly dominant LA MRSA, whereas CC9 predominated in most Asian countries (Cortimiglia et al, 2016; Sharma et al, 2016). In our study, all CC398 strains were identified as MSSA strains.…”

Characterization of Livestock-Associated Methicillin-ResistantStaphylococcus aureusCC398 andmecC-positive CC130 from Zoo Animals in the United Kingdom

“…Furthermore, we sought to detect the presence of sip, an integrase carried by the Staphylococcal pathogenicity island (SaPI) that usually carries bap. 22 Finally, a panel of the most common antimicrobial resistance genes found in the United Kingdom MRSA CC398 23 was also included for screening (ermA, ermB, ermC, tetK, tetM, aacA-aphD, fexA, cfr, and dfrK). [24][25][26][27][28] Positive and negative controls for PCR reactions were included in each assay.…”