Pyuria in Relation to Urine Culture and the Common Uropathogens with Respect to Age and Sex of Patients

Urinary tract infection (UTI) is one of the most common bacterial infection and urine samples account for a significant part of workload in clinical laboratories. There are different opinions regarding whether urinalysis or urine culture should be a routine. However, the cornerstone is based on the concept of significant bacteriuria and it is still considered as the gold standard in diagnosis of UTI. Many microorganisms can infect the urinary tract; however, E. coli causes approximately 80% of acute infections in patients.

The objectives of the study were to evaluate the reliability of urinary microscopy with semi-quantitative culture and to isolate and identify the common uropathogens with respect to age group of patients.

This prospective and descriptive type of study was carried out in a small size laboratory in Delhi within a period of six months, from January 2015 to July 2015.

A total of 502 non-duplicate, mid-stream urine samples were received from patients of all age groups from patients having signs and symptoms suggestive of UTI. Microscopic elements were evaluated from uncentrifused sample. For semiquantitative culture of urine, standard loop method was used on Cysteine Lactose Electrolyte Deficient (CLED) agar and incubated aerobically at 37°C for 18-24hrs.

Out of 502 non-duplicate samples, pyuria (> 5 cells/hpf) was found in 84 (16.73%) samples. Out of these 84 samples, 54(64.3%) had significant bacteriuria while 25 (30%) showed no growth in culture. Specificity and negative predictive value of pyuria in relation to culture was found to be 93% and 86% respectively. The most common isolate was Escherichia coli 84 (72%), followed by Klebsiella spp. 12(10%).

Pyuria along with significant bacteriuria is consistent for the diagnosis of UTI. However, it is always better to correlate culture with the urine microscopy.