Emergence of multidrug-resistant Enterobacter cloacae: nosocomial outbreak or change of microbial ecology?

Frequent selection of mutants resistant to extended and broad spectrum cephalosporins in Enterobacter cloacae is observed in hospital. As we noticed an unusual number of isolates of these strains and to answer the question arose whether these Enterobacter had a common source, we retrospectivally studied 56 strains collected in 11 wards of the hospital. Using PFGE with Spe 1 restriction analysis we identified a prevalent clone (11 patients) dispatched in 8 wards. We also obviously proved cross-contamination patients to patients with other clones. PFGE allow us to point out that clonal Enterobacter cloacae has taken place in our hospital, even if there is no real outbreak. A reinforcement of basic hygienic measures and a control of antibiotics prescription seemed very important to jugulate the sudden increase of multiresistant Enterobacter cloacae prevalence.