Vol. 4, Issue 7, Part F (2018)

Abstract
Calibrated platinum loop had come into general use in determining CFU in urine and found that it was comparable to the pour plate technique in determining the number of organisms present in urine. But later the it was considered only semiquantitative and not very reliable. Several other screening methods have been advocated for use in detecting bacteriuria like paper strips, nitrate reductase, TTC test, BACTEC^® automated screening system and catalase test have been developed by rapid screening of urine for bacteriuria. However, scanty information regarding this subject was found in the literature, particularly in relation to the possibility of compromising the sensitivity or specificity of the method by using urine volumes less than 50 μl. Hence, in this study, we carried out a comparative study of microscopic examination of un-centrifuged urine applied with a calibrated loop (10 μl) and stained with Grams staining, applied as a drop (50 μl) and examined as wet film, chemical tests of urine and counts of bacterial colonies cultured from urine samples. The study included the patients from Out-door and Indoor patients of Gynecology department which were recruited for bacteriologic evidence of asymptomatic bacteriuria by microscopy, culture and chemical examination. Patients included were randomly selected 3000 subjects who were married pregnant women reporting to ANC clinic of the Nair hospital of age group of 18 to 40 years. Collection, Transportation and Processing of urine like Microscopic examination (wet film and Gram staining), Chemical examination (Griess’s nitrite test and Triphenyl tetrazolium chloride test) and Semiquantitative urine culture using standard loop technique was carried out by standard methods. Sensitivity of Nitrite test, TTC test, Wet mount, Gram’s stain was 44.06%, 63.60%, 58.23% and 88.94% while specificity was 96.29%, 80.88%, 79.99% and 88.16% respectively, when compared to culture method. Total positive cultures was 8.26%. In approximately 100 % of the positive cultures, the etiological infective agent was isolated in pure culture, at a concentration of ≥10⁵ CFU/ml. Study results obtained in the present study demonstrated that the loop technique (10 μl) can be utilized as an alternative to the conventional drop technique (50 μl) for detecting significant bacteriuria. Also loop technique along with chemical test can be one of the better option with the advantage of greater rapidity and simplicity of execution. Still at the end culture method remains the gold standard for the detection of bacteriuria.