Risk factors for infection or colonization with CTX-M extended-spectrum-β-lactamase-positive Escherichia coli.
There has been a significant increase in the prevalence of Enterobacteriaceae that produce CTX-M-type extended-spectrum β-lactamases. The objective of this study was to evaluate risk factors for infection or colonization with CTX-M-positive Escherichia coli. A case-control study was conducted within a university system from 1 January 2007 to 31 December 2008. All patients with clinical cultures with E. coli demonstrating resistance to extended-spectrum cephalosporins were included. Case patients were designated as those with cultures positive for CTX-M-positive E. coli, and control patients were designated as those with non-CTX-M-producing E. coli. Multivariable logistic regression analyses were performed to evaluate risk factors for CTX-M-positive isolates. A total of 83 (56.8%) of a total of 146 patients had cultures with CTX-M-positive E. coli. On multivariable analyses, there was a significant association between infection or colonization with CTX-M-type β-lactamase-positive E. coli and receipt of piperacillin-tazobactam in the 30 days prior to the culture date (odds ratio [OR], 7.36; 95% confidence interval [CI], 1.61 to 33.8; P = 0.01) and a urinary culture source (OR, 0.36; 95% CI, 0.17 to 0.77; P = 0.008). The rates of resistance to fluoroquinolones were significantly higher in isolates from case patients than in isolates from control patients (90.4 and 50.8%, respectively; P < 0.001). We found that nonurinary sources of clinical cultures and the recent use of piperacillin-tazobactam conferred an increased risk of colonization or infection with CTX-M-positive E. coli. Future studies will need to focus on outcomes associated with infections due to CTX-M-positive E. coli, as well as infection control strategies to limit the spread of these increasingly common organisms.
Division of Infectious Diseases, Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA. jennifer.han@uphs.upenn.edu
Jennifer H
JH
Han
Kei
K
Kasahara
Paul H
PH
Edelstein
Warren B
WB
Bilker
Ebbing
E
Lautenbach
D000328:Adult; D000368:Aged; D000900:Anti-Bacterial Agents / Q000494:pharmacology / Q000627:therapeutic use*; D016022:Case-Control Studies; D004926:Escherichia coli / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics; D004927:Escherichia coli Infections / Q000188:drug therapy* / Q000382:microbiology; D005260:Female; D024841:Fluoroquinolones / Q000494:pharmacology / Q000627:therapeutic use*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010397:Penicillanic Acid / Q000031:analogs & derivatives* / Q000494:pharmacology / Q000627:therapeutic use; D010878:Piperacillin / Q000494:pharmacology / Q000627:therapeutic use*; D012044:Regression Analysis; D012307:Risk Factors; D000078142:Tazobactam; D018440:beta-Lactam Resistance / Q000187:drug effects; D001618:beta-Lactamases / Q000235:genetics / Q000378:metabolism*
D000900:Anti-Bacterial Agents; D024841:Fluoroquinolones; D010397:Penicillanic Acid; D001618:beta-Lactamases; D000078142:Tazobactam; D010878:Piperacillin