Clinical outcomes of spontaneous bacterial peritonitis due to extended-spectrum beta-lactamase-producing Escherichia coli and Klebsiella species: a retrospective matched case-control study.
BACKGROUND
Clinical outcomes of spontaneous bacterial peritonitis (SBP) due to extended-spectrum beta-lactamase-producing Escherichia coli and Klebsiella species (ESBL-EK) have not been adequately investigated.


METHODS
We conducted a retrospective matched case-control study to evaluate the outcomes of SBP due to ESBL-EK compared with those due to non-ESBL-EK. Cases were defined as patients with liver cirrhosis and SBP due to ESBL-EK isolated from ascites. Control patients with liver cirrhosis and SBP due to non-ESBL-EK were matched in a 3:1 ratio to cases according to the following five variables: age (+/- 5 years); gender; species of infecting organism; Child-Pugh score (+/- 2); Acute Physiological and Chronic Health Evaluation II score (+/- 2). 'Effective initial therapy' was defined as less than 72 hours elapsing between the time of obtaining a sample for culture and the start of treatment with an antimicrobial agent to which the EK was susceptible. Cephalosporin use for ESBL-EK was considered 'ineffective', irrespective of the minimum inhibitory concentration. ESBL production was determined according to the Clinical and Laboratory Standards Institute guidelines on stored isolates.


RESULTS
Of 1026 episodes of SBP in 958 patients from Jan 2000 through Dec 2006, 368 (35.9%) episodes in 346 patients were caused by SBP due to EK, isolated from ascites. Of these 346 patients, twenty-six (7.5%) patients with SBP due to ESBL-EK were compared with 78 matched controls. Treatment failure, evaluated at 72 hours after initial antimicrobial therapy, was greater among the cases (15/26, 58% vs. 10/78, 13%, P = .006); 30-day mortality rate was also higher than in the controls (12/26, 46% vs. 11/78, 15%, P = .001). When the case were classified according to the effectiveness of the initial therapy, 'ineffective initial therapy' was associated with higher 30-day mortality rate (11/18, 61% vs. 1/8, 13%, P = .036).


CONCLUSIONS
SBP due to ESBL-EK had poorer outcomes than SBP due to non-ESBL-EK. Ineffective initial therapy seems to be responsible for the higher rate of treatment failure and mortality in SBP due to ESBL-EK.
Song
Kyoung-Ho
KH
Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea. khsongmd@gmail.com
Jeon
Jae Hyun
JH
Park
Wan Beom
WB
Park
Sang-Won
SW
Kim
Hong Bin
HB
Oh
Myoung-don
MD
Lee
Hyo-Suk
HS
Kim
Nam Joong
NJ
Choe
Kang Won
KW
D000368:Aged; D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D001201:Ascites / Q000382:microbiology; D016022:Case-Control Studies; D002511:Cephalosporins / Q000627:therapeutic use; D004926:Escherichia coli / Q000201:enzymology / Q000472:pathogenicity; D004927:Escherichia coli Infections / Q000150:complications / Q000188:drug therapy* / Q000382:microbiology; D005260:Female; D006801:Humans; D015378:Imipenem / Q000627:therapeutic use; D007709:Klebsiella / Q000201:enzymology / Q000472:pathogenicity; D007710:Klebsiella Infections / Q000150:complications / Q000188:drug therapy* / Q000382:microbiology; D008103:Liver Cirrhosis / Q000150:complications / Q000188:drug therapy; D008297:Male; D008875:Middle Aged; D010538:Peritonitis / Q000150:complications / Q000188:drug therapy* / Q000382:microbiology; D012189:Retrospective Studies; D012307:Risk Factors; D017211:Treatment Failure; D018440:beta-Lactam Resistance; D001618:beta-Lactamases / Q000096:biosynthesis
D000900:Anti-Bacterial Agents; D002511:Cephalosporins; D015378:Imipenem; D001618:beta-Lactamases