An outbreak of hospital-acquired Klebsiella pneumoniae bacteraemia, including strains producing extended-spectrum beta-lactamase.

This study describes the clinical outcome of an outbreak of extended-spectrum beta-lactamase producing Klebsiella pneumoniae (ESBL-KP) bacteraemia. Ninety-two episodes of hospital-acquired K. pneumoniae bacteraemia were studied, 49 ESBL-KP and 43 non-ESBL-KP, from May 1993 to June 1995. Of these, 44 (90%) episodes of ESBL-KP vs. 20 (46%) episodes of non-ESBL-KP occurred in intensive care unit (ICU) patients. The incidence of K. pneumoniae bacteraemia (mainly due to ESBL-KP) increased in the ICU during the outbreak. A significant association was found between intravascular catheter-related bacteraemia and isolation of ESBL-KP [27 (56%) in the ESBL-KP group vs. 13 (30%) in the non-ESBL-KP group;P= 0.01]. The worst prognostic features were identified as age > 65 years (P= 0.02), septic shock (P< 0.001) and secondary bacteraemia (P= 0.04). High rates of resistance to beta-lactam/beta-lactamase inhibitors observed in our ESBL-KP isolates, as well as variable activity of aminoglycosides, restricts the empirical use of these antibiotics. Carbapenems should be the treatment of choice since they are uniformly active against these strains. Our study shows that ESBL-KP bacteraemia occurring in an epidemic ICU setting is mainly catheter-related. We did not find ESBL strains to be associated with a significantly poor outcome.