Background and Aim: Klebsiella pneumoniae is a member of the Enterobacteriaceae family. There is a global emergence of multidrug-resistant (MDR) strains of K. pneumoniae, a Gram-negative enteric bacterium that causes nosocomial and urinary tract infections. The aims of the present study were to identify the Klebsiella pneumoniae infections in hospitalized patients, characterization of bla_CTX gene, detection cross-resistance and cefepime susceptible-dose dependent (SDD) in isolates.

Materials and Methods: In present study, 111 strains of Klebsiella pneumoniae were isolated from patients hospitalized in Ghotbadden, Faghihi and Nemazee hospitals (Shiraz, Iran). The isolates were identified as K.pneumoniae, based on biochemical tests embedded in the API-20E system. Susceptibility testing (disc diffusion) was performed according clinical and laboratory standards institute (CLSI) guidelines. Detection cefepime susceptible-dose dependent (SDD) was performed. The detection of AmpC β-lactamases producing strains was done based on cefoxitin and cefepime disk tests. The bla_CTX gene was detected in the isolates by PCR molecular method.

Results: Total 111 Klebsiella pneumoniae isolates were studied. The less effective drug was ceftazidime (37.8% isolates were sensitive). All SDD strains were susceptible to colistin and imipenem. Colistin (96.4%) and imipenem (88.3%) were the most effective antibiotics against isolates. Respectively, 41.4% and 35.1% isolates displayed resistance to gentamicin and amikacin. All colistin resistant isolates were imipenem sensitive. The results of PCR on bla_CTX gene showed that 70.3% of the isolates possess the gene.

Conclusion: Carbapenem drugs are effective against Klebsieella pneumoniae infections. These results indicate that multidrug-resistant (MDR) and extensively drug resistant (XDR) strains of K.pneumoniae are rising, and fewer antibiotics may be useful for treating infections caused by these strains. Routine investigation and reporting of antibiotics resistance profile in patients presenting with Klebsiella infections is suggested.