Applied Microbiology: Open Access
Open Access
ISSN: 2471-9315
+44 1300 500008
ISSN: 2471-9315
+44 1300 500008
Juhee Ahn, Jeongjun Kim and Laeseung Jeong
Kangwon National University, Republic of Korea
Scientific Tracks Abstracts: Appli Micro
The multidrug resistance in K. pneumoniae is primarily mediated by the production of different classes of �²-lactamases. The relationship between �²-lactamase production and resistance phenotype is essential to understand the resistance mechanisms in K. pneumoniae. However, there is still a lack of information on the phenotypic and genotypic antibiotic resistance profiles in association with the classes of �²-lactamases in K. pneumoniae. Therefore, the aim of this study was to evaluate the antibiotic susceptibility and �²-lactamase production in ciprofloxacin-induced and clinically-isolated antibiotic-resistant K. pneumoniae strains, based on the interaction between �²-lactamases and �²-lactamase inhibitors. The antibiotic susceptibility and �²-lactamase activity of K. pneumoniae strains, including antibiotic-sensitive K. pneumoniae (KPWT), ciprofloxacin-induced resistant K. pneumoniae (KPCIP) and clinically isolated K. pneumoniae strains (KPCI237, KPCI263 and KPCI272), were determined in the absence and presence of �²-lactamase inhibitors (BLI 489, sulbactam, clavulanate and tazobactam). All strains were highly resistant to ampicillin in the absence of �²-lactamase inhibitors (MICâ�¥512 �µg mL-1). In the presence of clavulanate, the MICs of ampicillin and piperacillin against KPWT were decreased by >64-fold and 4-fold, respectively. The resistance of KPCI263 to cefotaxime, ceftazidime, ceftriaxone and piperacillin were increased in the presence of BLI-489. The antibiotic susceptibilities KPCI237 to �²-lactams were not noticeably changed in the presence of �²-lactamase inhibitors (clavulanate, sulbactam and tazobactam). KPWT, KPCIP and KPCI272 were positive for blaSHV, blaAmpC and blaFOX/MOX, KPCI237 for blaSHV and blaAmpC and KPCI263 for blaSHV and blaOXA-48. The antibiotic susceptibility corresponded well with the results obtained from dual disc diffusion assay, which was in good agreement with the �²-lactamase production. The results provide useful information for understanding the resistance phenotypes in association with �²-lactamase production.
Juhee Ahn has received his PhD degree majoring in Food Microbiology at the University of Missouri, Columbia, USA and continued his work as a Postdoctoral Research Assistant in Food Microbiology Lab at the University of Missouri (2003-2004) and Food Safety Engineering Lab at the Ohio State University (2004-2006). He is interested in the microbial pathogenesis, including the mechanistic studies of antibiotic resistance, bacterial infection and bacteriophage control. He was a Visiting Scholar at the University of Maryland (2012-2013) as well as Zhejiang University (2016-2017). Currently, he is a Professor at the Department of Medical Biomaterials Engineering, Kangwon National University. South Korea.