[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.