Livestock-Associated MRSA in Household Members of Pig Farmers: Transmission and Dynamics of Carriage, A Prospective Cohort Study

Abstract

This prospective cohort study describes carriage of livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) in household members from 49 farrowing pig farms in the Netherlands (2010–2011). Of 171 household members, 4% were persistent MRSA nasal carriers, and the MRSA prevalence on any given sampling moment was 10% (range 7-11%). Working in the stables (of which 98% was MRSA-positive, prevalence ratio (PR) = 2.11 per 10 hours), working with sows (PR=1.97), and living with an MRSA-positive pig farmer (PR=4.63) were significant determinants for MRSA carriage. Significant protective factors were carriage of methicillin-susceptible Staphylococcus aureus (MSSA) (PR=0.50), and wearing a facemask when working in the stables (37% decreased prevalence). All MRSA strains during the study period were known livestock-associated types. The bacteriophage φ3 was not found in household members. Transmission from pigs and the environment appeared to be important determinants; human-to-human transmission could not sufficiently be differentiated. Wearing a facemask when working in the stables and carriage of MSSA are potential interventional targets.

Risk factors for persistence of livestock-associated MRSA and environmental exposure in veal calf farmers and their family members: an observational longitudinal study

“…Environmental contamination with dust particles containing MRSA is much lower in veal calf farming as compared with pig farming and associations are less evident 34. As shown in table 3, no difference in the environmental MRSA load was found across persistent, intermittent and non-carrier farms at the beginning of the production cycle.…”

Evidence for Human Adaptation and Foodborne Transmission of Livestock-Associated Methicillin-ResistantStaphylococcus aureus: Table 1.

“…For example, it may be that case F acquired CC9/CC398 from his brother, who owns an animal farm in Egypt. Previous reports have shown that transmission of CC398 indeed occurs from livestock workers to their family members [8–10]. In contrast, sustained chains of person-to-person transmission appear to be rare, both in the community and hospital settings [3, 11].…”

Prevalence and correlates of MRSA and MSSA nasal carriage at a Ugandan regional referral hospital

“…19,20 Based on studies demonstrating that PCR-based detection methods are the gold standard for MRSA detection in lowprevalence settings, 16 we expect the Cepheid Xpert SA Nasal Complete assay performed well in our setting. However, our findings are limited by the cross-sectional study design, which does not allow for risk estimates or follow-up of colonized individuals.…”