extended-spectrum β-lactamase and carbapenemase production among burn and non-burn clinical isolates of klebsiella pneumoniae

background and objectives: klebsiella pneumoniae is an opportunistic pathogen responsible for up to 10% of nosocomial infections. the emergence and spread of multidrug resistant k. pneumoniae , mostly due to the production of extended-spec- trum β-lactamases (esbl) and carbapenemases, is often responsible for antibiotic treatment failure of these infections. we compared the antibiotic resistance profiles, esbl and carbapenemase production as well as presence of kpc-type genes in burn and non-burn clinical isolates of k. pneumoniae . materials and methods: fifty five clinical isolates were collected from shahid motahari (25 burn isolates) and shariati (30 non-burn isolates) hospitals between august 2011 to january 2012. antibiotic susceptibility was determined to 12 antibiot- ics using disc diffusion. the phenotypic confirmatory test (pct) was used to screen for esbl production. carbapenemase activity was measured by the modified hodge test (mht) and kpc-type carbapenemases were further sought by pcr using specific primers. results: both groups were highly resistant to cefotaxime and ceftazidime (>92%). burn isolates were significantly more resistant to cefepime, amoxiclav, imipenem, meropenem, gentamicin and ciprofloxacin compared to the non-burn strains (p<0.05). no significant differences were observed in esbl production between the two groups. carbapenem resistance was only observed among the burn isolates (n=5, 9.1%). five carbapenem-resistant isolates produced carbapenemases. however, none of the isolates harbored the kpc-type genes. conclusion: higher rates of drug resistance were observed in burn isolates of k. pneumoniae compared to the non-burn strains. carbapenemase phenotype was only observed among the burn isolates but kpc-type gene was not detected.