Publication:

Third generation cephalosporin-resistance in Klebsiella pneumoniae isolates: an emerging threat

Background Newer generation cephalosporin-resistance among Klebsiella pneumoniae organisms has increased recently. Present study is undertaken to find incidence, antimicrobial susceptibility and prevalence of extended spectrum beta-lactamase (ESBL) in K. pneumoniae isolates in a tertiary care hospital.

Methods Prospective study was carried out between June to December 2011. Samples of pus, blood, urine, cerebro-spinal fluid, stool, peritoneal, pleural and synovial fluid were collected from indoor and outdoor patients for isolation and antimicrobial susceptibility pattern of K. pneumoniae in the department of microbiology, G.R. Medical College Gwalior, M.P. Ceftazidime resistant K. pneumoniae were subjected to Phenotypic Confirmatory Disc Diffusion Test (PCDDT) and Double Disc Synergy Test (DDST) for detection of ESBL.

Results Out of 2480 samples collected a total of 530 K. pneumoniae were isolated and subjected to antimicrobial susceptibility. Antibiotic sensitivity to imipenem, cefoperazone, amikacin and ofloxacin were 82, 74, 73 and 72% respectively whereas sensitivity to ceftizoxime, ceftriaxone cefotaxime, ceftazidime ranged between 47-50%. K. pneumoniae were found to be resistant to ampicillin, co-trimoxazole, doxycycline and gentamicin, by 91, 82, 54 and 50% respectively. Among third generation cephalosporins K. pneumoniae were least sensitive (47%) to ceftazidime. About 33 and 32% of the ceftazidime resistant strains were found to be ESBL positive by PCDDT and DDST respectively.

Conclusions This study has shown that prevalence of ESBL producing K. pneumoniae is the most important reason for increased resistance to third generation cephalosporins. There is need to carry out tests for detection of ESBL producing bacteria routinely.