Laboratory aspects of asymptomatic bacteriuria in pregnancy.
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.
Mohammad
Marlyn
M
Department of Medical Microbiology and Immunology, Faculty of Medicine, Hospital Universiti Kebangsaan Malaysia, Cheras, Kuala Lumpur, Malaysia. marlyn@medic.ukm.my
Mahdy
Zaleha A
ZA
Omar
Jamil
J
Maan
Noorashikin
N
Jamil
M A
MA
D000293:Adolescent; D000328:Adult; D001437:Bacteriuria / Q000175:diagnosis* / Q000188:drug therapy / Q000453:epidemiology / Q000382:microbiology; D024881:Drug Resistance, Bacterial; D005260:Female; D006801:Humans; D015994:Incidence; D008296:Malaysia / Q000453:epidemiology; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D010865:Pilot Projects; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious / Q000175:diagnosis* / Q000188:drug therapy / Q000453:epidemiology / Q000382:microbiology; D011296:Prenatal Diagnosis / Q000379:methods*; D016482:Urinalysis / Q000379:methods