Tehran University of Medical Sciences Journal of Medical Bacteriology 2251-8649 1 3-4 2015 10 12 17 24 EN Anand Kalaskar Department of Microbiology, Prathima Institute of Medical Sciences, Karimnagar, Andhra Pradesh, India. Kandi Venkataramana Department of Microbiology, Prathima Institute of Medical Sciences, Karimnagar, Andhra Pradesh, India. 2015 10 12 2015 10 12 Background: The prevalence of antibiotic resistance among extended spectrum  β-lactamase  (ESBL)  producing  Escherichia  coli  and  Klebsiella  pneumoniae  has been increased  markedly  in recent  years. The present study was done to know the prevalence  of ESBL production among isolates of E. coli and K. pneumoniae and to study the susceptibility pattern of isolates against different antibiotics. Methods:  Extended spectrum  β-lactamase  producing  E.  coli  and  K.pneumoniae were isolated from various samples obtained from outdoor and indoor patients of the Prathima Institute of medical sciencesdisc synergy test and resistance to various antibiotics like fluoroquinolones,  cephalosporins,  aminoglycosides  and  ß-lactamase  inhi- bitor combinations and susceptibility to carbapenems were determined by Kirby-Bauer disc diffusion method. Results: A total of 94 ESBL producing isolates were obtained. Of them 60 were E. coli and 34 K. pneumoniae. They were obtained from urine, sputum, pus, wound swabs blood & tracheal aspirates. Urine (38.29%) was the main source of ESBL-producing isolates from all patients, fol lowed by sputum (34.04%).  About 37.23% of these isolates were collected from medical wards and 27.65% were collected from outdoor. All isolates were susceptible to imipenem. The resistance to cephalos porins (1-4 generations)  was almost 100%. Resistance  to Aztreonam, Ampicillin and Coamoxyclav was also 100%. A high degree of resis tance was observed to other antibiotics. Conclusion:  The highest prevalence  of resistance to ESBL in E. coli and K. pneumonia is associated with a multitude of infections in hospi talized patients with a significant longer duration of hospital stay, increased morbidity and greater hospital charges. Advanced  drug resistance surveillance and molecular characteristics of ESBL isolates is ne- cessary to guide the proper and judicious antibiotic use. https://jmb.tums.ac.ir/index.php/jmb/article/view/20 https://jmb.tums.ac.ir/index.php/jmb/article/download/20/16