Prevalence and characterization of mecC MRSA in bovine bulk tank milk in Great Britain, 2017–18

Abstract

Objectives To evaluate the current prevalence status of mecC MRSA among dairy farms in England and Wales 5 years after a previous survey conducted in 2011–12. Methods A convenience sample of 697 dairy farms in England and Wales was used for the study, conducted in 2017–18, testing bulk tank milk samples for the presence of mecC MRSA using high salt broth enrichment and chromogenic MRSA agar selection. All putative MRSA isolates were screened by PCR for the presence of mecA and mecC genes and subjected to antimicrobial susceptibility testing using both the disc diffusion method and VITEK® 2. MRSA isolates were also sequenced for genomic characterization. Results mecC MRSA were detected on 4 out of 697 dairy farms in England and Wales (prevalence 0.57%, 95% CI 0.16%–1.46%). Three of the mecC isolates were ST425 and one was ST4652 (in the CC130 lineage). Two mecA MRSA were also isolated: one ST5 and one ST398. Conclusions These results indicate that there has been a substantial reduction in the prevalence of mecC MRSA in England and Wales with a 72% reduction (2.15% to 0.57%) compared with a previous study. While the levels of mecA MRSA remain very low the continued presence of ST398, a livestock-associated MRSA, suggests that this lineage is established in the UK.

The European Union Summary Report on Antimicrobial Resistance in zoonotic and indicator bacteria from humans, animals and food in 2019–2020

“…It was also reported from horses (1 isolate) and dairy cows (1) in Denmark. The association of this spa ‐type with CC130 has previously been observed in cattle (Mališová et al., 2020 ; Cui et al., 2021 ; Silva et al., 2021 ). mecC ‐MRSA spa‐ type t3256, also CC130 was reported by Denmark in one isolate from horses.…”

Role of milk and milk products in the spread of methicillin‐resistant Staphylococcus aureus in the dairy production chain

“…No MRSA strains were detected both in cow and goat milk in Poland (Rola, Korpysa-Dzirba, et al, 2015;Rola, Sosnowski, et al, 2015). In Great Britain, Cui et al (2021) 1).…”

“…In Great Britain, Cui et al. (2021) isolated both mecA and mecC MRSA from bulk tank milk, with values of 0.29% and 0.57%, respectively. Tegegne et al.…”

“…The maximum values were observed in Saudi Arabia (Alghizzi & Shami, 2021) and Egypt (Zayda et al., 2020), with a values of 72.8% and 60%, respectively. However, the minimum values were assigned to bulk tank milk in Great Britain (0.29%; Cui et al., 2021) and sheep milk in Italy (0.57%; Carfora et al., 2016) (Table 1). It is important to notice that the frequencies of MRSA isolation in milk and milk products differed between studies conducted in different areas among different countries or even regions within the same country, which might reflect the heterogeneity of the methods used and factors such as the type of tested samples (geographical origin, manufacturing technology, use of pasteurized or raw milk, sample storage, and handling), sensitivity of the MRSA screening methods, and the sample size (Al‐Ashmawy et al., 2016; Gharsa et al., 2019).…”

“…Other minor lineages including ST5 (CC5), ST8 (CC8), and ST97 (CC97) have been identified in milk and milk products through different continents. ST5 (CC5) was isolated from cow milk (Cui et al., 2021; Gazzola et al., 2020; Haran et al., 2012; Parisi et al., 2016; Song et al., 2015; Tegegne et al., 2018; Titouche et al., 2020), cheese (Basanisi et al., 2017; Gonzalez et al., 2017), and acidified milk (Titouche et al., 2020) (Table 2). The ST5 lineage can be considered as an animal‐adapted clone since it was reported in companion animals, poultry, pigs, and cattle, in addition to humans (Aires‐de‐Sousa, 2017; Pantosti, 2012).…”