Antimicrobial Effects of beta-Lactams on Imipenem-Resistant Ceftazidime-Susceptible Pseudomonas aeruginosa
- Authors
- Wi, Y.M.[Wi, Y.M.]; Choi, J.-Y.[ Choi, J.-Y.]; Lee, J.-Y.[ Lee, J.-Y.]; Kang, C.-I.[Kang, C.-I.]; Chung, D.R.[Chung, D.R.]; Peck, K.R.[Peck, K.R.]; Song, J.-H.[Song, J.-H.]; Ko, K.S.[Ko, K.S.]
- Issue Date
- Jun-2017
- Publisher
- AMER SOC MICROBIOLOGY
- Keywords
- Carbapenem resistance; Ceftazidime susceptible; Inoculum effect; Pseudomonas aeruginosa; Time-kill assay
- Citation
- ANTIMICROBIAL AGENTS AND CHEMOTHERAPY, v.61, no.6
- Indexed
- SCIE
SCOPUS
- Journal Title
- ANTIMICROBIAL AGENTS AND CHEMOTHERAPY
- Volume
- 61
- Number
- 6
- URI
- https://scholarworks.bwise.kr/skku/handle/2021.sw.skku/28711
- DOI
- 10.1128/AAC.00054-17
- ISSN
- 0066-4804
- Abstract
- We studied the resistance mechanism and antimicrobial effects of beta-lactams on imipenem-resistant Pseudomonas aeruginosa isolates that were susceptible to ceftazidime as detected by time-kill curve methods. Among 215 P. aeruginosa isolates from hospitalized patients in eight hospitals in the Republic of Korea, 18 isolates (23.4% of 77 imipenem-resistant isolates) were imipenem resistant and ceftazidime susceptible. Multilocus sequence typing revealed diverse genotypes, which indicated independent emergence. These 18 isolates were negative for carbapenemase genes. All 18 imipenem-resistant ceftazidime-susceptible isolates showed decreased mRNA expression of oprD, and overexpression of mexB was observed in 13 isolates. In contrast, overexpression of ampC, mexD, mexF, or mexY was rarely found. Time-kill curve methods were applied to three selected imipenem-resistant ceftazidime-susceptible isolates at a standard inoculum (5 X 10(5) CFU/ml) or at a high inoculum (5 X 10(7) CFU/ml) to evaluate the antimicrobial effects of beta-lactams. Inoculum effects were detected for all three beta-lactam antibiotics, ceftazidime, cefepime, and piperacillin-tazobactam, against all three isolates. The antibiotics had significant killing effects in the standard inoculum, but no effects in the high inoculum were observed. Our results suggest that beta-lactam antibiotics should be used with caution in patients with imipenem-resistant ceftazidime-susceptible P. aeruginosa infection, especially in high-inoculum infections such as endocarditis and osteomyelitis.
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Collections - Medicine > Department of Medicine > 1. Journal Articles
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