Isolation, Identification and Plasmid Profiling of Multidrug Resistant Bacterial Pathogens Isolated from Uti Patients
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Department of Microbiology
Abstract
A study on the antibiotic susceptibility pattern of the bacteria isolated from Urine samplesof suspected UTI patients was carried out. The plasmid profiling of multidrug resistantisolatesand antibiotic resistance transfer mechanism was also studied.
The study was carried out during May 2007 to January 2008.Seven hundred and ten mid-stream urine samples received in the laboratoryofKathmandu Model Hospital, Kathmanduwere processed for routine culture.The antimicrobial susceptibility of bacterial isolates wasdeterminedbyKirby-Bauer disk diffusion technique.The isolates which showed resistantto more than two different structural classes antibiotics were considered as multidrugresistant. The plasmids of multidrug resistant isolates wereextractedandelectrophoresed.The antibiotic resistance transfer study was carried outbyconjugation and transformationexperimentinthe laboratory ofCentral Department of Microbiology,Kirtipur, Kathmandu.
Only 30.85% (219/710) of the samples showed significant bacterial growth. Status of bacteriuriawas found higher in females (33.52%) than in males (23.71%). Association of significantbacteriuria and gender of patients was found to be statistically significant (P<0.05). Status ofbacteriuria was found higher in age group 20-29 (34.25%).Altogether 16 different bacterialgenerawere isolated from all culture positive urine samples.Escherichia coli (81.28%) wasfound to be the most predominant organism.
In all theE.coli isolates, 38.20%were Multidrug resistant.Among the MDRE. coli 95.58%isolates were resistant toNorfloxacin,94.11% toAmpicillin, 92.64% to Ciprofloxacinand86.76% toCo-trimoxazole.
Conjugation experiment showed that 100% (10/10) resistant isolates possessed the conjugativetypes of plasmids. The plasmid profile showed that the donors having 51, 38, 32.5 Kb plasmidswere found to be transferred completely. Most of the isolates and their transconjugants had highdegree of resistance against Ampicillin, Ciprofloxacin, Cefixime, Trimethoprim and Norfloxacin(MIC >1024).
Key words:Bacteriuria, Urinary Tract Infection, Mid-stream urine, Multidrug-resistance,Plasmid profiles, MIC