Bloodstream infections caused by qnr-positive Enterobacteriaceae: clinical and microbiologic characteristics and outcomes.
The clinical significance of plasmid-mediated quinolone resistance determinant qnr has not been well characterized. We investigated the clinical and microbiologic characteristics and outcomes of bloodstream infections (BSIs) caused by qnr-positive Enterobacteriaceae. We prospectively collected 351 nonduplicate consecutive blood isolates of Enterobacter spp. and Klebsiella pneumoniae. qnr genes were detected by polymerase chain reaction and confirmed by sequencing. The medical records of patients were retrospectively reviewed. qnr genes were detected in a total of 26 isolates. A comparison of these 26 qnr-positive and 297 qnr-negative Enterobacteriaceae BSIs in adult patients showed that the population characteristics and clinical features of BSIs were similar between the qnr-positive and qnr-negative groups. However, patients with hematologic malignancies, solid organ transplant recipients, and BSIs caused by strains with multiple antimicrobial resistance, including extended-spectrum beta-lactamase (ESBL) resistance, were more common in the qnr-positive group. Previous antibiotic therapy and prior use of trimethoprim-sulfamethoxazole or aminoglycosides were significantly associated with BSIs caused by qnr-positive strains. In the multivariate analysis, prior use of trimethoprim-sulfamethoxazole (odds ratio [OR], 5.55; 95% confidence interval [CI], 1.47-20.94) and having an underlying disease other than solid tumor (OR, 4.06; 95% CI, 15.07) were independently associated with qnr-positive Enterobacteriaceae BSIs. There was no significant difference in 30-day mortality rates between the qnr-positive and qnr-negative groups (15.4% [4/26] versus 13.8% [41/297], P = 0.77). Although qnr determinants were significantly associated with multiple antimicrobial resistance including ESBL resistance, they did not affect clinical outcomes of BSIs.
Department of Infectious Diseases, Asan Medical Center, University of Ulsan College of Medicine, Seoul, 138-736, Republic of Korea.
Yong Pil
YP
Chong
Sang-Ho
SH
Choi
Eun Sil
ES
Kim
Eun Hee
EH
Song
Eun Jung
EJ
Lee
Ki-Ho
KH
Park
Oh-Hyun
OH
Cho
Sung-Han
SH
Kim
Sang-Oh
SO
Lee
Mi-Na
MN
Kim
Jin-Yong
JY
Jeong
Jun Hee
JH
Woo
Yang Soo
YS
Kim
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D016470:Bacteremia / Q000188:drug therapy / Q000382:microbiology*; D001426:Bacterial Proteins / Q000235:genetics*; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D024881:Drug Resistance, Bacterial; D004754:Enterobacter / Q000187:drug effects* / Q000302:isolation & purification; D004756:Enterobacteriaceae Infections / Q000188:drug therapy / Q000382:microbiology*; D005260:Female; D006801:Humans; D007711:Klebsiella pneumoniae / Q000187:drug effects* / Q000302:isolation & purification; D008297:Male; D008875:Middle Aged; D010957:Plasmids; D016133:Polymerase Chain Reaction; D011446:Prospective Studies; D015363:Quinolones / Q000494:pharmacology*; D017422:Sequence Analysis, DNA; D016896:Treatment Outcome; D055815:Young Adult
D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D004269:DNA, Bacterial; D015363:Quinolones