Investigating the impact of the definition of previous antibiotic exposure related to isolation of extended spectrum β-lactamase-producing Klebsiella pneumoniae.
BACKGROUND
Previous antibiotic exposure is a risk factor for extended spectrum β-lactamase (ESBL)-producing Klebsiella pneumoniae isolation, but the optimal definition of previous antibiotic exposure remains unclear.


METHODS
This was a retrospective, case-control study comparing 88 patients with ESBL-producing K pneumoniae (cases) and 88 patients with non-ESBL-producing K pneumoniae (controls). Three previous antibiotic exposure definitions were analyzed, including durations of 30, 60, and 90 days prior to organism isolation.


RESULTS
The mean cohort age was 63.6 ± 16.9 years, 43% were male, and 86% were black. In bivariate analysis, third-generation cephalosporins and cefepime were associated with ESBL-producing K pneumoniae isolation, and the odds ratios (OR) were significant regardless of previous antibiotic exposure definition. However, for fluoroquinolones and ampicillin/sulbactam, the ORs varied as a function of previous antibiotic exposure definition. In multivariate analysis, third-generation cephalosporin usage was a risk factor for ESBL-producing K pneumoniae isolation, whereas ampicillin/sulbactam usage was protective against these organisms, regardless of the time frame analyzed. Other independent predictors of ESBL-producing K pneumoniae included nursing home residence (OR, 9.30 [95% confidence interval: 3.69-23.43]) and hemodialysis (OR, 13.60 [95% confidence interval: 4.29-43.17]).


CONCLUSIONS
Prior use of third-generation cephalosporins, nursing home residence, and hemodialysis were independent risk factors for isolation of an ESBL-producing K pneumoniae regardless of the time frame analyzed.
Detroit Medical Center, Detroit, MI.
Suprat
S
Saely
Detroit Medical Center, Detroit, MI; Sinai-Grace Hospital, Detroit, MI; Wayne State University School of Medicine, Detroit, MI.
Keith S
KS
Kaye
Detroit Medical Center, Detroit, MI; Wayne State University School of Medicine, Detroit, MI.
Marilynn R
MR
Fairfax
Detroit Medical Center, Detroit, MI; Wayne State University School of Medicine, Detroit, MI.
Teena
T
Chopra
Detroit Medical Center, Detroit, MI; Sinai-Grace Hospital, Detroit, MI; Wayne State University School of Medicine, Detroit, MI. Electronic address: jpogue@dmc.org.
Jason M
JM
Pogue
D001741:Black or African American; D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D016022:Case-Control Studies; D000077723:Cefepime; D002511:Cephalosporins / Q000494:pharmacology; D015331:Cohort Studies; D003428:Cross Infection / Q000188:drug therapy / Q000453:epidemiology / Q000382:microbiology; D005260:Female; D024841:Fluoroquinolones / Q000494:pharmacology; D006801:Humans; D007710:Klebsiella Infections / Q000188:drug therapy / Q000453:epidemiology* / Q000382:microbiology; D007711:Klebsiella pneumoniae / Q000187:drug effects / Q000201:enzymology / Q000302:isolation & purification*; D008297:Male; D008824:Michigan / Q000453:epidemiology; D008875:Middle Aged; D015999:Multivariate Analysis; D009735:Nursing Homes; D016017:Odds Ratio; D006435:Renal Dialysis; D012189:Retrospective Studies; D012307:Risk Factors; D014481:United States; D001618:beta-Lactamases / Q000187:drug effects*
D000900:Anti-Bacterial Agents; D002511:Cephalosporins; D024841:Fluoroquinolones; D000077723:Cefepime; D001618:beta-Lactamases