Assessment of antibiotic resistance in bacteriophage-insensitive Klebsiella pneumoniae

초록

This study was design to evaluate the physiological properties of bacteriophage-insensitive Klebsiella pneumoniae (BIKP) mutants in association with the antibiotic cross -resistance, beta-lactamase activity, and gene expression. Klebsiella pneumoniae ATCC 23357(KPWT), ciprofloxacin-induced antibiotic-resistant K. pneumoniae ATCC 23357 (KPCIP), and clinically isolated antibiotic-resistant K. pneumoniae 10263 (KPCLI) were used to isolate BIKP mutants against KPB1, PBKP02, PBKP21, PBKP29, PBKP33, and PBKP35. PBKP35-induced mutants, including bacteriophage-insensitive K. pneumoniae ATCC 23357 (BIKPWT), ciprofloxacin-induced K. pneumoniae ATCC 23357 (BIKCIP), and clinically isolated antibiotic-resistant K. pneumoniae CCARM 10263 (BIKCLI). BIKPWT BIKPCIP, and BIKPCLI were resistant to Klebsiella bacteriophages, KPB1, PBKP02, PBKP21, PBKP29, and PBKP33., The antibiotic cross-resistance to cefotaxime, cephalothin, chloramphenicol, ciprofloxacin, erythromycin, kanamycin, levofloxacin, and nalidixic acid was observed in BIKPWT. The relative expression levels of vagC was increased by more than 8-folds in BIKPWT, corresponding to the increased beta-lactamase activity. The aac(6')-1b-cr was overexpressed in BIKP mutants, responsible for aminoglycoside and quinolone resistance. The phage-resistant mutants decreased the antibiotic susceptibilities in association with D-lactamase activity and antibiotic resistance-related gene expression. The results pointed out the cross-resistance of BIKP mutants to antibiotics, which might be considered when applying for the therapeutic use of bacteriophage.

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