Epidemiology and biomolecular characterization of carbapenem-resistant klebsiella pneumoniae in an Italian hospital

Objective. To describe the occurrence of CRKP infections in a tertiary care hospital and to analyse the allelic profiles of the clinical strains involved and the most frequent carbapenemases. Design. The study analyzed cases of infection due to CRKP in the period 2013-2014; 147 cases were recorded, most of which (82.31%) were in-hospital infections. Setting. A hospital in northern Italy. Methods. We retrospectively collected: data on patient characteristics and the microbiological characteristics of CRKP. Isolates from 72 of the in-hospital cases underwent molecular typing (MLST); in addition, in each isolate, a procedure for the detection of the blaKPC gene was carried out. Results. The in-hospital death rate was 24.0% in 2013 and 37.5% in 2014. However, the difference between these two values did not prove statistically significant (P > .05). Analysis of mortality revealed that bloodstream infections were more frequently associated with death than other infections (X2 = 14.57, P < .001). The age-adjusted Cox proportional hazard model revealed that the patients with bacteremia due to CRKP had a 3-fold higher risk of death (HR 3.11; 95% CI 1.66 - 5.84, P< .001) than those with infections of other sites. MLST revealed that the prevalent allelic profile was ST 512 (79.62%); the most frequent carbapenemase was KPC-3 (83.8%). Conclusions. Our results are in line with those of recent studies, which have shown that the spread of CRKP in Italy is a matter of concern and that further efforts have to be made to prevent the potential dissemination of carbapenemase-producing clones of K. pneumoniae, whenever possible.