French regional surveillance program of carbapenemase-producing Gram-negative bacilli: results from a 2-year period

A. Pantel, A. Boutet-Dubois, H. Jean-Pierre, H. Marchandin, A. Sotto, J.-P. Lavigne, on behalf of the CARB-LR group

In February 2011, the CARB-LR group was created as a sentinel laboratory-based surveillance network to control the emergence of carbapenem-resistant Gram-negative bacilli (CR GNB) in a French Southern Region. We report the epidemiological results of a 2-year study. All the Gram-negative bacilli isolates detected in the different labs (hospital and community settings) of a French Southern Region and with reduced susceptibility to ertapenem and/or imipenem were characterised with regard to antibiotic resistance, bla genes content, repetitive sequence-based polymerase chain reaction (rep-PCR) profiles and multilocus sequence typing (MLST). A total of 221 strains were analysed. Acinetobacter baumannii was the most prevalent carbapenemase-producing bacteria, with a majority of OXA-23 producers (n = 37). One isolate co-produced OXA-23 and OXA-58 enzymes. Klebsiella pneumoniae was the most frequent carbapenemase-producing Enterobacteriaceae (CPE) (OXA-48 producer: n = 29, KPC producer: n = 1), followed by Escherichia coli (OXA-48 producer: n = 8, KPC producer: n = 1) and Enterobacter cloacae (OXA-48 producer, n = 1). One isolate of Pseudomonas aeruginosa produced a VIM-1 carbapenemase. A clonal diversity of carbapenemase-producing K. pneumoniae and E. coli was noted with different MLSTs. On the other hand, almost all OXA-23-producing A. baumannii strains belonged to the widespread ST2/international clone II. The link between the detection of CR GNB and a foreign country was less obvious, suggesting the beginning of a local cross-transmission. The number of CR GNB cases in our French Southern Region has sharply increased very recently due to the diffusion of OXA-48 producers.