Carbapenem resistance among Klebsiella pneumoniae isolates: risk factors, molecular characteristics, and susceptibility patterns.
BACKGROUND
Carbapenem resistance among isolates of Klebsiella pneumoniae has been unusual.


OBJECTIVE
To identify risk factors for infection with carbapenem-resistant K. pneumoniae (CRKP) and to characterize microbiological aspects of isolates associated with these infections.


METHODS
Retrospective case-control study.


METHODS
A 900-bed tertiary care hospital.


RESULTS
From January 2006 through April 2007, K. pneumoniae was isolated from 461 inpatients; 88 had CRKP infection (case patients), whereas 373 had carbapenem-susceptible K. pneumoniae infection (control subjects). The independent risk factors for infection with CRKP were prior fluoroquinolone use (odds ratio [OR], 1.87 [95% confidence interval [CI], 1.07-3.26]; P=.026), previous receipt of a carbapenem drug (OR, 1.83 [95% CI, 1.02-3.27]; P=.042), admission to the intensive care unit (OR, 4.27 [95% CI, 2.49-7.31]; P<.001), and exposure to at least 1 antibiotic drug before isolation of K. pneumoniae (OR, 3.93 [95% CI, 1.15-13.47]; P=.029). All CRKP isolates carried the bla(KPC) gene. Approximately 90% of the tested isolates carried the bla(KPC-2) allele, suggesting patient-to-patient transmission. Almost all CRKP isolates were resistant to all antibiotics, except to colistin (resistance rate, 4.5%), gentamicin (resistance rate, 7%), and tigecycline (resistance rate, 15%).


CONCLUSIONS
CRKP should be regarded as an emerging clinical threat. Because these isolates are resistant to virtually all commonly used antibiotics, control of their spread is crucial.
Hussein
Khetam
K
Infectious Diseases Unit, Rambam Medical Center, Haifa, Israel.
Sprecher
Hanna
H
Mashiach
Tania
T
Oren
Ilana
I
Kassis
Imad
I
Finkelstein
Renato
R
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D015780:Carbapenems / Q000494:pharmacology*; D003428:Cross Infection / Q000382:microbiology / Q000635:transmission; D024881:Drug Resistance, Bacterial / Q000235:genetics*; D005260:Female; D006801:Humans; D007557:Israel / Q000453:epidemiology; D007710:Klebsiella Infections / Q000382:microbiology / Q000635:transmission; D007711:Klebsiella pneumoniae / Q000187:drug effects* / Q000201:enzymology / Q000235:genetics / Q000302:isolation & purification; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D015995:Prevalence; D012307:Risk Factors; D001618:beta-Lactamases / Q000235:genetics
D000900:Anti-Bacterial Agents; D015780:Carbapenems; C491478:beta-lactamase KPC-2; D001618:beta-Lactamases