[Clinical and epidemiological study of an outbreak of KPC-producing Klebsiella pneumoniae infection in Buenos Aires, Argentina].

INTRODUCTION: KPC-producing Klebsiella pneumoniae (Kpn-KPC) is an emerging pathogen, with a high capacity of nosocomial spread. The aim of this study was to describe the clinical and epidemiological characteristics of a nosocomial outbreak of Kpn-KPC in Buenos Aires, Argentina.

METHODS: Prospective and descriptive study. We recorded clinical and epidemiological characteristics of patients with Kpn-KPC infection (august 2009 to july 2010). Antimicrobial susceptibility was performed by disk-diffusion antibiogram and an automated method (bioMerieux Vitek(®) 2C). Screening for K. pneumoniae carbapenemase (KPC) was performed with the 3-aminophenyl-boronic acid (APB) test inhibition and its presence was confirmed by PCR. Molecular typing of isolates was performed by pulsed field gel electrophoresis (PFGE).

RESULTS: Twenty seven patients were infected by KPC producing K. pneumoniae (surgical care unit: n=8; medical care unit: n=6; intensive care unit [ICU]): n=5; emergency care unit: n=4; and other: n=4). All Kpn-KPC isolates belonged to a single clonal type (ST258). Site of infection: urinary tract (63%), respiratory tract (15%), intra-abdominal (15%), bloodstream (7%) and bone (4%). All Kpn-KPC isolates were only susceptible to tigecycline and colistin. Inappropriate empirical treatment: 63%. Specific treatment for Kpn-KPC infection: colistin (74%), tigecycline (4%) and tigecycline+colistin (22%).Global mortality: 59% (attributable mortality: 26%). Positive surveillance cultures (swabs): 7/70 (10%).

CONCLUSIONS: We described the emergence of a nosocomial outbreak of Kpn-KPC in Buenos Aires, with a high capacity for dissemination and a high mortality rate. The implementation of infection control measures is essential to reduce the nosocomial spread of Kpn-KPC.