Isolation of Pathogenic Gram-Negative Bacteria from Urinary Tract Infected Patients

This study investigated the susceptibility pattern of different bacteria isolated from urinary tract infection to different antibiotics. 83 uropathogen bacteria were isolated from 300 urine samples taken from patients attended to Tikrit Teaching Hospital from March, 2011 through February, 2012. The patients were males and females aged between 4 days to 95 years. Bacteria obtained from urine samples were cultured and tested for antimicrobial susceptibility to 16 kinds of antibiotics. Urine samples were cultured on different media and incubated, thereafter bacteria were isolated and purified by streaking four times on the same media;isolates were identified depending on morphological, microscopic, and biochemical characteristics. The isolated strains of bacteria were tested for their susceptibility to some antibiotics using disk diffusion method. The antagonistic activity was evaluated by observing a clear zone of inhibition growth. The results showed that the bacterial species of Eschericia coli, Proteus mirabilis, Klebsiella pneumonia, Citrobacter diversus, Citrobacter freundii, Enterobacter aerogenes, Yersinia pestis, Pseudomonas aeruginosa, Klebsiella oxytoca and Hafnia alvei were identified in 44 (53%), 18 (21.7%), 4 (4.8%), 4 (4.8%), 3 (3.6%), 3 (3.6%), 3 (3.6%), 2 (2.4%), 1 (1.2%) and 1 (1.2%), respectively, of the isolates. The results of antimicrobial susceptibility test showed that 83 (100%) isolates were resistant to Ampicillin, Rifampicin and Erythromycin. 75 (90.3%) isolates were resistant to Cefotaxime, 67 (80.7%) isolates were resistant to Tobramyci. 66 (79.5%), 65 (78.3%), 56 (67.4%) and 48 (57.8%) isolates showed susceptibility to Nalidixic acid, Tetracycline, Nitrofurantoin, Chloramphenicol, respectively. 45 (54.2%) isolates were resistant to Azithromycin, Norfloxacin and Ciprofloxacin. Meropenem, Gentamicin, Amikacin, and Imipenem show significant effect on 35 (42.1%), 32 (38.5%), 27 (32.5%) and 1 (1.2%) isolates, respectively. In conclusion, significant bacteria count isolated from urine samples is pathogenic. The most effective antibiotic in inhibiting the bacterial growth was Imipenem while Ampicillin, Rifampicin and Erythromycin showed no effect on all 83 isolates (100%).