Molecular typing of multiresistant Klebsiella pneumoniae isolated from children from northern Jordan.

Abstract

Twenty-nine clinical isolates of community acquired Klebsiella pneumoniae obtained from 17 children with malnutrition were characterized by antibiotic susceptibility, plasmid analysis, and random amplified polymorphic DNA (RAPD) techniques. Disc diffusion methodology was used to test the susceptibility of the isolates to 13 antibiotics: amoxycillin, cephapirin, ceftazidime, cefoxitin, cefotaxime, aztreonam, gentamicin, ciprofloxacin, chloramphenicol, erythromycin, nalidixic acid, trimethoprim and amoxycillin-clavulanic acid. All the isolates showed multiresistance patterns (15 patterns) ranging from resistance to two antibiotics to resistance to 10 antibiotics. All isolates were resistant to amoxycillin and erythromycin. Ten K. pneumoniae isolates producing extended-spectrum beta-lactamases (ESBLs) as evidenced by the double-disc diffusion synergy test were isolated sporadically from six patients. Six of these 10 isolates were hyperproducers of ESBL, which resulted in increased resistance to the beta-lactam-beta-lactamase inhibitor combination amoxycillin-clavulanic acid. Plasmid analysis showed plasmid ranging in size from 48 kilobases (kb) to 1.4 kb. All the 29 isolates shared the same plasmid 26 kb. There was a consistent relationship between antibiotype and plasmid profiles for each pair of isolates obtained from five individual patients. RAPD analysis using a single (10-mer) primer demonstrated that the isolates that have the same antibiotype and the same plasmid profile had different RAPD fingerprint patterns. These results demonstrate that the RAPD technique is better than antibiotype characterization and a plasmid analysis profile for typing K. pneumoniae as well as for revealing strain differences.