Prevalence of Multiple Drug ResistantClinical Isolates of Extended-Spectrum Beta- Lactamase Producing Enterobacteriaceaein Southeast Iran

Background: multidrug resistance and production of extendedspectrum Ĉ-lactamases (esbls) by enteric gramnegativerods in hospitals and community continue to beworsened. we aimed to characterize the multidrug resistanceand determine the prevalence of esbl production by clinicalisolates of enterobacteriaceae in southeast iran.methods: gram-negative bacteria isolated from clinical samplesof hospital inpatients and outpatients from three hospitalsin southeast iran were tested for susceptibility to 10commonly used antimicrobials. for 500 isolates whichshowed resistance to .3 antibiotics from different classes,minimum inhibitory concentration, and prevalence of esblproduction were determined by agar dilution and double discsynergy method respectively. the isolated bacterial specieswere compared in respect of antibacterial resistance, esblproduction, patients' gender, hospital ward, and type ofspecimen.results: the most frequent resistance was to trimethoprim/sulfamethoxazole, amoxicillin, and tetracycline. imipenemwith 99.8% and ceftizoxime with 83% susceptibility were themost active agents. a total of 53.8% of isolates expressedesbl production. escherichia coli and klebsiella pneumoniaewere most common in outpatients, and inpatients samplesrespectively. higher rate of resistance to most antibacterialagents and esbl production was found in samples ofinpatients.conclusion: the present study showed high prevalence ofesbl-producing enterobacteriaceae especially in the patientsadmitted to hospital. infection control strategy with continuousresistance surveillance is essential to monitor in vitro susceptibilityto antibacterial agents currently used in clinicalpractice. determination of the type of involved esbl enzymesis important for a better antimicrobial control and empiricaltherapy of critically ill patients in hospitals.