Study of Bacteria Causing Urinary Tract Infection and Their Antimicrobial Resistance Trend at National Public Health Laboratory

Abstract

Thepresent study was conducted at National Public Health Laboratory, Teku from May toSeptember 2006 with the objectives to isolate bacteria causingurinary tract infectionand todetermine their antimicrobial resistance trend. During this period, three hundred and fifty twomid-stream urine samples collected were investigated by conventional semi-quantitative culturetechnique, microscopy and antibiotic susceptibility test. Only 22.7% (80/352) of the samples showed significant bacterial growth. Status of bacteriuriawas found higher in females (29.8%) than in males (15.2%). Association of significant bacteriuriaand gender of patients was found to be statistically significant (P<0.05). Status of bacteriuria wasfoundhigher in age group 21-30 (21.6%) followed by 31-40 (18.8%). Altogether11 differentbacteria were isolated among whichEscherichia coli(48.8%) was foundthe most predominant organisms followed byKlebsiella pneumoniae(18.8%),Proteus mirabilis(7.5%),Proteus vulgaris(6.3%), Coagulase-negative Staphylococci (5.0%),K. oxytoca(3.8%),Enterobacterspp. (3.8%),Citrobacter freundii (2.5%),Acinetobacterspp. (1.3%),Alcaligenesspp. (1.3%) andStaphylococcus aureus(1.3%). Predictors concerning pus cell count (≥5/HPF) and RBC count (≥3/HPF) were analyzed todetermine the positive predictive value (PPV) in relation to the significant bacteriuria. Positivepredictive value for pus cell count was found to be higher (77.8%) than that of RBC count(39.6%). Gramnegative bacilli showed best susceptibility towards gentamicin (80.0%) followed byceftriazone (76.0%)whereas ampicillin was found out to be the least effective drug.Nitrofurantoin(100.0%)was found to bethe most effective against Grampositive bacteria. Multidrug resistance (MDR) was observed in 45.0% (36/80) of total bacterial isolates. Multidrugresistance was foundto be 51.3% (20/39) inE. coliand that inKlebsiella pneumoniaewas 33.3 %(5/15). Higherrateof MDR was found in males (57.7%, 15/26) than in females (38.8%,21/54).Among the MDRE. coli isolates, 100.0%, 90.0% and 65.0% were resistant to ampicillin,norfloxacinandcotrimoxazolerespectively.Among the MDRK. pneumoniae isolates, 100.0%were resistant to ampicillin, cotrimoxazole and norfloxacin. Key words:bacteriuria, urinary tract infection,mid-stream urine, pyuria, multidrug-resistance