Epidemiology and molecular characterisation of metallo-β-lactamase-producing Enterobacteriaceae in a university hospital Intensive Care Unit in Greece

Evangelos Koratzanis (1) , Maria Souli (1) , Irene Galani (1) , Zoi Chryssouli (1) , Apostolos Armaganidis (2) , Helen Giamarellou (3)

1 4th Department of Internal Medicine
2 Department of Critical Care Medicine (Attikon University)
3 6th Department of Internal Medicine

The molecular epidemiology of VIM-producing Enterobacteriaceae isolated at the beginning of an epidemic in the Intensive Care Unit (ICU) of a university hospital in Athens, Greece, was studied. All Gram-negative organisms isolated from March 2004 to November 2005 positive for metallo-β-lactamase (MBL) production were submitted to polymerase chain reaction (PCR) and sequencing, to repetitive sequence-based PCR (Rep-PCR) for molecular typing, and to S1 nuclease digestion for plasmid DNA characterisation. Conjugation experiments and isoelectric focusing were performed to identify co-existing β-lactamases. Among 23 patients, 12 suffered one or more clinical infections. Eighty-two isolates representing one isolate per clone, source and ICU patient were studied, including (77), (2), (1) and (2). High clonal diversity was detected among the , with 10 distinct clones identified. Conjugation was successful in 54.5% of , and five different sized plasmids were detected. All and both isolates shared the same -containing class 1 integron structure also carrying , and gene cassettes. The isolate carried a different integron that included and . Both isolates were positive for . It was not possible to identify specific clones with the potential to cause clinical infections. In conclusion, a multiclonal cluster of MBL-producers was responsible for the first cases of colonisation and/or infection in the ICU. A single integron structure, common in Greek hospitals, efficiently disseminated between clones and species, suggesting that the epidemic was mainly the result of successful horizontal transfer of mobile genetic material rather than the result of horizontal transfer of one or a few clones.

Mots clés: VIM; Carbapenems; Integron

Domaines: Microbiologie et Parasitologie

Evangelos Koratzanis, Maria Souli, Irene Galani, Zoi Chryssouli, Apostolos Armaganidis, et al.. Epidemiology and molecular characterisation of metallo-β-lactamase-producing Enterobacteriaceae in a university hospital Intensive Care Unit in Greece. International Journal of Antimicrobial Agents, 2011, 38 (5), pp.390. ⟨10.1016/j.ijantimicag.2011.06.014⟩. ⟨hal-00736740⟩