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Background and Objective: Klebsiella species are gram-negative bacteria with positive voges proskauer (VP) reaction. Klebsiella species are found as commensal in human digestive and respiratory system. This group of organisms can create a serious health hazards in hospitalized patients, and their ability to drug resistance is a major health problems. This study was done to evaluate the efficacy of Ciprofloxacin, Ceftizoxims and Carbenicillin on Klebsiella species isolated from hospital specimens. Materials and Methods: In this laboratory study, 1200 clinical samples were isolated from patients in Imam Khomeini hospital, Tehran, Iran. The identification Klebsiella species were carried out according to conventional biochemical tests. The minimum inhibitory concentration (MIC) of carbenicillin, ceftizoxime, and ciprofloxacin antibiotics were determined using Macrodilution broth test. Results: Out of 1200 isolated samples, 25% were identified as Klebsiella species. 73% of identified Klebsiella were obtained from urine samples. Klebsiella.peumoniae with rate of 94% was the most abundant among other species. The results of MIC and minimum bactericidal concentration by using standard microdilution method showed drug resistance range of 16-1024 μg/ml, 4-256 μg/ml and 0.25-16 μg/ml for carbenicillin, ceftizoxime, and ciprofloxacin, respectivley. In general, 94%, 6% and 1% of species were resistance to carbenicillin, ceftizoxime and ciprofloxacin, respectively. Conclusion: Ciprofloxacin and Ceftizoxime are suitable for the treatment of infections due to Klebsiella species.

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Background and Objective: Extended-Spectrum Beta Lactamase enzymes (ESBLs) are the most important factor for antimicrobial resistance in Enterobacteriaceae The resistance to beta-lactam antibiotics is the main problem in the bacterial infections therapy. This study was done to determine the prevalence of Extended-Spectrum Beta Lactamase enzymes in clinical isolates of Enterobacteriaceae family.

Methods: In this descriptive study, 240 isolates of Enterobacteriaceae family were collected from clinical specimens obtained in Shohada, Rahimi and Madani hospitals in Khorramabad city, Iran. Antibiotic susceptibility of isolates was performed by disk diffusion method. ESBLs production in all isolates was determined using the combination disk method.

Results: Bacteria strains isolated in this study were Escherichia coli (76%), Klebsiella pneumonia (16.2%), Citrobacter (5.4%), Enterobacter spp. (0.83%) and Proteus (1.6%). The results of antimicrobial susceptibility of isolates showed that the highest rate of antibiotic resistance was toward Ampicillin (88%) and Cefotaxime (43%) and the lowest rate was observed to Amikacin (2.5%). According to the results of the phenotypic tests, 141(59%) isolates out of 240 Enterobacteriaceae were beta-lactamase producers.

Conclusion: ESBL producer isolates and antibiotic resistant due to of Enterobacteriaceae isolated from clinical samples from hospitals are high prevalence in Khorramabad city, Iran.