Brigitte A. G. L. van Cleef

We describe the impact of methicillin-resistant Staphylococcus aureus (MRSA) in two neighbouring regions in Europe with a comparable population size, North Rhine-Westphalia (NRW) in Germany and the Netherlands. We compared the occurrence of MRSA in blood cultures from surveillance systems. In the Netherlands in 2009, 14 of 1,510 (0.9%) Staphylococcus aureus bacteraemia episodes under surveillance were MRSA. Extrapolation using the number of clinical admissions results in a total of 29 MRSA bacteraemia episodes in the Netherlands or 1.8 episodes per 1,000,000 inhabitants. In 2010 in NRW, 1,029 MRSA bacteraemias were reported, resulting in 57.6 episodes of MRSA bacteraemia per 1,000,000 inhabitants: a 32-fold higher incidence than in the Netherlands. Based on an estimated attributable mortality of 15%, the Dutch approach would save approximately 150 lives per year by the prevention of bacteraemia only.

Studies frequently use nasal swabs to determine Staphylococcus aureus carriage. Self-sampling would be extremely useful in an outhospital research situation, but has not been studied in a healthy population. We studied the similarity of self-samples and investigator-samples in nares and pharynxes of healthy study subjects (hospital staff) in the Netherlands.

To estimate the proportion of methicillin-resistant Staphylococcus aureus (MRSA) isolates from humans that were sequence type (ST) 398, we surveyed 24 laboratories in 17 countries in Europe in 2007. Livestock-associated MRSA ST398 accounted for only a small proportion of MRSA isolates from humans; most were from the Netherlands, Belgium, Denmark, and Austria.

Recently, livestock-associated methicillin-resistant Staphylococcus aureus CC398 has been discovered in animals, livestock farmers and retail meat. This cross-sectional study aimed to determine the spread to persons not in direct contact with livestock in areas with a high density of pig farms. With a random mailing in 3 selected municipalities in the Netherlands, adult persons were asked to fill in a questionnaire and to take a nose swab. In total, complete information was obtained on 583 persons. Of the 534 persons without livestock-contact, one was positive for MRSA (0.2%; 95% confidence interval, spa-types belonged to CC398. Livestock-associated MRSA has a high prevalence in people with direct contact with animals. At this moment it has not spread from the farms into the community.

SUMMARY: Livestock-associated MRSA has been found in various animals, livestock farmers and retail meat. This study aimed to determine the prevalence and determinants of nasal MRSA carriage in pig slaughterhouse workers. Three large pig slaughterhouses in The Netherlands were studied in 2008 using human and environmental samples. The overall prevalence of nasal MRSA carriage in employees of pig slaughterhouses was 5·6% (14/249) (95% CI 3·4–9·2) and working with live pigs was the single most important factor for being MRSA positive (OR 38·2,Pr=0·75). In conclusion, a high prevalence of nasal MRSA carriage was found in pig-slaughterhouse workers, and working with live pigs is the most important risk factor. Exact transmission routes from animals to humans remain to be elucidated in order to enable application of targeted preventive measures.