It is important to diagnose and treat urinary tract infection in children before renal damage has taken place. Hence a new screening procedure will be of interest. This study was conducted to evaluate the efficacy of urinary nitrite in screening for asymptomatic bacteriuria among school children compared to a more traditional method. Of the 44,816 school children investigated 240 (0.54%) students were judged to have bacteriuria ie 82 (0.19%) in boys and 158 (0.35%) in girls. Escherichia coli was the commonest organism isolated (28.75%). Urine dipstick testing for nitrite was found to have a low sensitivity and positive predictive value. While urinalysis for pyuria was noted to have a sensitivity of 77.9%, a specificity of 95.8% and a negative predictive value of 99.9%.
Urinary tract infection is the most common of bacterial infections. Screening children for asymptomatic bacteriuria to prevent pyelonephritis and renal scarring is widely recommended. In Malaysia no such attempt has been made to establish the prevalence of asymptomatic bacteriuria. Bacteriuria was screened among 44,816 healthy school children from three different districts in Kelantan. There were 23,132 boys and 21,684 girls. The prevalence of bacteriuria was 0.12% after second screening. Higher prevalence was seen in other reports.
A total of 1,661 pregnant women aged between 13 and 45 years were screened for bacteriuria by urine culture. Of the 1,661 culture results, 615 (37%) yielded no growth; 728 (43.8%) yielded no significant growth (presence of <10(5) organisms/ml urine of one or more types of bacteria); 286 (17.2%) yielded mixed growth (presence of >10(5) organisms/ml urine of more than one type of bacteria) and only 32 (1.9%) showed significant growth (presence of >10(5) organisms/ml urine of a single bacterium). Urine microscopy was also conducted. Two hundred and twenty-four (13.5%) specimens had >10 white blood cells/ml urine, of which 66 had >100 white blood cells; 13 were from the significant growth group. Three hundred and seventy-four (22.5%) specimens showed the presence of bacteria, 42 (2.5%) had red blood cells, 370 (22.3%) had epithelial cells, 58 (3.5%) had crystals, and 14 (0.8%) had yeasts. The most common bacterium isolated was Escherichia coli (12; 40%); the others included group B Streptococcus (5; 15%), Klebsiella spp (5; 15%), Diphtheroids (2), and Candida albicans (2). Fifty-two percent of tested strains were sensitive to ampicillin; 24 of 28 strains (85.7%) were sensitive to ciprofloxacin; all 7 strains tested were sensitive to nitrofurantoin and all 20 strains tested were sensitive to cotrimoxazole; 14/20 (70%) and 16/17 (94.1%) were sensitive to cephalexin and cefuroxime respectively. This study shows that asymptomatic bacteriuria does occur in pregnant women, albeit at a very low rate in an urban setting like Cheras. Urine microscopy is not specific and only serves as a guide to bacteriuria. The commonest causative organisms are those from the gastrointestinal tract and vagina. The antibiogram showed that cefuroxime and cephalexin are likely to be effective in treating bacteriuria: ampicillin must be reserved for Gram-negative organisms. For Gram-positive organisms, of which Group B Streptococcus is important, ampicillin is still effective in vitro. Nitrofurantion and cotrimoxazole have excellent activity in vitro and should be considered for therapy. 17.2% of the urine culture yielded mixed growth: likely to indicate that contamination of urine specimens still happens despite the strict instructions given to patients about the collection of a midstream urine specimen. Proper collection, appropriate transport, and the early processing of urine specimens remain essential.