OBJECTIVE:

To evaluate the impact of extended-spectrum β-lactamase (ESBL) on clinical outcome and medical cost in patients with bloodstream infection (BSI) due to Klebsiella pneumoniae.

METHODS:

A retrospective study was conducted in patients admitted into Changhai Hospital between January 2013 and December 2014, who suffered from BSI due to Klebsiella pneumoniae during hospitalization. Patients were divided into two groups according to whether Klebsiella pneumoniae produced ESBL (ESBL positive group and ESBL negative group). They were matched with propensity score matching method in a 1∶1 ratio and then multiple regression model was used to analyze the impact of ESBL on clinical outcome and medical cost. Clinical outcome was evaluated by 30-day mortality post BSI; medical cost was evaluated by total length of stay (LOS), post-BSI LOS, total hospital cost and antimicrobial cost.

RESULTS:

Before matching, the two groups were significantly different in age, nosocomial infection rate, LOS before BSI and surgical rate during hospitalization (all P<0.05). The ESBL-positive group had higher 30-day mortality post BSI (21.3% vs 8.7%, P=0.054), and higher total LOS [25.0(12.0, 33.0) vs 16.0(10.0, 23.0) d, P=0.015], post-BSI LOS [16.0(9.0, 26.0) vs 10.0(5.0, 16.0) d, P=0.006], total hospital cost [69 409(40 605, 198 021) vs 45 683(28 448, 67 000) ￥, P<0.001] and antimicrobial cost [10 279(4 815, 25 500) vs 3 783(1 596, 11 879) ￥, P<0.001]. After matching, the two groups had no significant differences in clinical characteristics such as sex, age, nosocomial infection rate, LOS before BSI, APACHEⅡ score, Charlson Comorbidity Index, underlying diseases and surgical rate during hospitalization (all P>0.05). Multiple regression analysis indicated that ESBL could significantly increase the total LOS, post-BSI LOS, total hospital cost and antimicrobial cost (all P<0.001), but did not increase the 30-day mortality post BSI (P=0.910).

CONCLUSIONS:

ESBL can significantly increase the medical cost in patients with BSI due to Klebsiella pneumoniae but does not increase the 30-day mortality post BSI.