Prevalence of carbapenemase producing Enterobacteriaceae isolated from German pig-fattening farms during the years 2011–2013

Since recently Enterobacteriaceae carrying blaVIM-1 genes have been isolated in German animal husbandries, the monitoring of carbapenemase producing Enterobacteriaceae (CPE) in livestock became a major topic within the European Union. Nevertheless, due to missing surveillance studies the worldwide situation in livestock and livestock associated surroundings might still be underestimated. The here described study provides an overview of the CPE-prevalence in German pig-fattening farms during the years 2011–2013 (period when previously described blaVIM-1 findings occurred on pig-fattening farms (Efsa, 2011; Fischer et al., 2012, 2013a)). Therefore, a collection of 238 bacterial anacultures derived from pooled faeces and boot swab samples, collected in a cross-sectional study including 58 pig-fattening farms throughout Germany, were investigated. The bacteria were selected on MacConkey agar plates containing 0.125 μg/ml meropenem. Enterobacteriaceae which were able to grow on these plates were further investigated for the presence of carbapenemase genes. Out of eight CPE-suspicious strains, two Escherichia (E.) coli strains—deriving from the same farm—contained the carbapenemase gene blaVIM-1. For the remaining six Enterobacteriaceae it seems to be likely that they possess other resistance mechanisms, leading to reduced carbapenem susceptibility. Based on the obtained results, the overall CPE prevalence for German pig-fattening farms, sampled during the years 2011–2013 was 1.7%; 95% CI: 0–10. However, as it is of great importance to prevent a further spread of these bacteria between farms and livestock populations as well as their introduction into the food chain, an understanding of their routes of introduction and spread in combination with intensified monitoring programs are considered necessary.