Antibiogram of Extended Spectrum Beta-lactamase (ESBL) producing Escherichia coli and Klebsiella pneumoniae isolated from Hospital Samples

Abstract

Extended spectrum beta-lactmase (ESBL) producing organisms create a major problem for clinical therapeutics. The frequency of ESBL producing strains among clinical isolates has been steadily increasing over the past few years resulting in limitation of the therapeutic options. These resistant bacteria are emerging world wide as a threat to human health in both the community and hospital settings. -lactamase production by several organisms is the most important mechanism of resistance to beta-lactam antibiotics, such as penicillins and cephalosporins. This study was done to determine the susceptibility of different antimicrobials to ESBL producing Escherichia coli and Klebsiella pneumoniae isolated from wound swabs, blood, urine, fluid, tracheal aspirates and sputum in Shahid Bahonar Hospital of Tehran from July, 2007 to June, 2008. A total of 115 ESBLproducing isolates were obtained from outdoor and indoor patients. Out of 115 isolates, 60% were E. coli and 40% were K. pneumoniae. All ESBL-producing isolates were confirmed using the Clinical and Laboratory Standards Institute (CLSI)-approved double-disk diffusion method. 29.6% of these isolates were collected from medical wards and 24.3% were collected from outdoor. Urine (70.4%) was the main source of ESBL-producing isolates from all patients, followed by blood (16.5%). All isolates were susceptible to both imipenem and meropenem. Of all isolates, 93.9% were susceptible to amikacin. The cephalosporins (1-4 generations) were almost 100% resistant. For Nitrofurantoin, 57.4% were sensitive. High rate resistance (74.8%) was observed to all quinolones tested. Aztreonam, Ampicillin, Co-amoxyclav and Ampicillin/Sulbactam were 100% resistant. This study shows that the frequency of ESBL producing strains of E. coli and K. pneumoniae is high in both hospital and community levels and it has a significant implication for patients’ management. Advance drug resistance surveillance and molecular characteristics of ESBL isolates is necessary to guide the appropriate and judicious antibiotic use. Key words: Extended spectrum beta-lactamase (ESBL), Drug sensitivity, Escherichia coli, Klebseilla pneumoniae DOI: http://dx.doi.org/10.3329/bjmm.v4i1.8467 BJMM 2011; 4(1): 32-36