Livestock-associated MRSA: epidemiology in animal production chains, transmission to humans and charateristics of the clone.Original Title Veegerelateerde MRSA: epidemiologie in dierlijke productieketens, transmissie naar de mens en karakterisering van de kloon.

摘要

MRSA infections in people working with pigs was confirmed in 2005. Dutch data from 9 abattoirs showed that 39% of pigs and 81% of slaughter batches was contaminated with MRSA. All strains belonged to the sequence type ST398. This clone is now known as livestock-associated MRSA (LA-MRSA). A research project in the Netherlands investigated during 2007-08 the spread of MRSA on 202 pig farms. MRSA was found on 68.3% of farms. One of the main risk factors was farm size. MRSA in farm workers varied between 2% in people not handling pigs directly to 29% in people handling pigs. Farms with MRSA-positive suppliers were also MRSA-psoitive in 79% of cases compared to 23% in farms with MRSA-negative suppliers. Pigs can get contaminated with MRSA within hours after staying in contaminated areas. A study of veal calf farms reported 27.5% of infected calves and 88% of infected farms. Significant positive relationships were found between MRSA-infection and calf age, number of calves per box, presence of other livestock, and use of antibiotics. MRSA infection rates varied between 33% in farm workers (handling calves) to 8% in family members (not handling calves). A strong relationship was also found between MRSA infection and number of working hours/week. A survey of 40 lots of broilers identified 35% of animals as MRSA-infected, including 6.9% of throat infections. MRSA prevalence of farm workers was 5.6% and risks were higher in farm workers handling live broilers. MRSA was detected in 11.9% of meat products but levels were below 10 units/g meat. Most MRSA isolates were resistant to tetracycline. ST398 has 3 phylogenetic lines. The human health risks of ST398 infection are small.