Heteroresistance to cephalosporins and penicillins in Acinetobacter baumannii

Kuei Hsiang Hung, Ming Cheng Wang, Ay Huey Huang, Jing Jou Yan, Jiunn Jong Wu

研究成果: Article同行評審

28 引文 斯高帕斯(Scopus)


Heteroresistance to antimicrobial agents may affect susceptibility test results and therapeutic success. In this study, we investigated heteroresistance to cephalosporins and penicillins in Acinetobacter baumannii, a major pathogen causing nosocomial infections. Two A. baumannii isolates exhibited heteroresistance to ampicillin-sulbactam, ticarcillin-clavulanic acid, cefepime, and cefpirome, showing a distinct colony morphology of circular rings within the inhibition halos. Pulsed-field gel electrophoresis (PFGE) and outer membrane protein (OMP) analysis demonstrated that subpopulations around the disks/Etest strips and the original strains all belonged to the same PFGE type and OMP profile. Population analysis profile (PAP) showed the presence of heteroresistant subpopulations with high cefepime resistance levels in two isolates (008 and 328). Interestingly, A. baumannii 008 contained two peaks: one was grown in the presence of up to 1 μg of cefepime/ml, the other apparently occurred when the concentration of cefepime was raised to 256 μg/ml. After serial passages without exposure to cefepime, the PAP curve maintained the same trend observed for the original strain of A. baumannii 008. However, the PAP curve showed a shift to relatively lower cefepime resistance (from 256 to 64 μg/ml) in A. baumannii 328 after 10 passages in antibiotic-free Mueller-Hinton agar plates. Convergence to a monotypic resistance phenotype did not occur. Growth rate analysis revealed that slower growth in resistant subpopulations may provide a strategy against antibiotic challenge. To our knowledge, this is the first report of heteroresistance to cephalosporins and penicillins in A. baumannii.

頁(從 - 到)721-726
期刊Journal of Clinical Microbiology
出版狀態Published - 2012 3月

All Science Journal Classification (ASJC) codes

  • 微生物學(醫學)


深入研究「Heteroresistance to cephalosporins and penicillins in Acinetobacter baumannii」主題。共同形成了獨特的指紋。