Incidence of invasive meticillin-resistant Staphylococcus aureus infections in Germany, 2010 to 2014

Voluntary surveillance systems in Germany suggest a recent decline in the incidence of infections (subsequent to at least 2010) with meticillin-resistant Staphylococcus aureus (MRSA) from various types of specimens and settings. We asked whether this decline is reflected by data from the mandatory national surveillance system for invasive MRSA infections. Our analysis is based on the population in Germany in 2010 to 2014. Cases were identified from passive reporting by microbiological laboratories of the diagnosis of MRSA from blood culture or cerebrospinal fluid. Respective clinical data were subsequently added to the notification. We calculated risk ratios (RR) between consecutive years, stratifying cases by sex, age and federal state of residence. The national incidence increased from 4.6 episodes per 100,000 persons in 2010 to 5.6 in 2012 (2011 vs 2010: RR: 1.13, 95% confidence interval (CI): 1.08-1.18; 2012 vs 2011: RR: 1.08, 95% CI: 1.04-1.13). It stagnated at 5.4 per 100,000 in 2013 (RR: 0.97, 95% CI: 0.93-1.01) before declining to 4.8 in 2014 (RR: 0.88, 95% CI: 0.84-0.91). This trend was observed in most, but not all federal states and strata of sex and age groups. Only 204 of 20,679 (1%) episodes of infection were notified as belonging to an outbreak. Our analysis corroborates previous findings that the incidence of invasive MRSA infections in Germany may be declining.