An outbreak of CTX-M-15-producing Klebsiella pneumoniae isolates in an intensive care unit of a teaching hospital in Kuwait

Abstract

Objective: This study reports an outbreak of Klebsiella pneumoniae infections in 14 patients during a 2-month period (August–September, 2008) in the intensive care unit (ICU) of a teaching hospital in Kuwait. Materials and Methods: The clinical sources were blood (9), urine (3) and respiratory secretions (2) identified by the automated VITEK-2 ID System. Susceptibility testing was performed by the E-test method. Extended-spectrum β-lactamase (ESBL) production was assessed using the ESBL E-test and confirmed by PCR. Carriage of bla genes was determined by PCR and sequence analysis. The transferability of resistance phenotypes was demonstrated by conjugation experiments and clonal relatedness was determined by PFGE. Results: The isolates were susceptible to imipenem, meropenem, and tigecycline and produced ESBL. All isolates yielded an amplicon of 499 bp with universal consensus primers (MA primers). DNA sequence analysis showed that they all harboured blaCTX-M-15and blaTEM-1genes. The environmental isolate obtained from a suction machine was also CTX-M-15/TEM-1 producer. The resistance phenotypes were transferrable to the Escherichia coli J53r strain. PFGE, revealed two clones, A and B, related with a Dice coefficient of >94.1%. A mortality rate of 21.4% was recorded. Conclusion: The outbreak was contained by robust and aggressive infection control measures. This study highlights the first outbreak of CTX-M-15-producing K. pneumoniae associated with high mortality in an adult medical ICU in Kuwait.