Urinary Tract Infection Due to <i>Streptococcus agalactiae</i> - A Missed Clinical Entity: A Study from a Tertiary Care Center in Southern India

Background: Streptococcus agalactiae (group B Streptococcus or GBS) commonly causes various urinary tract infections (UTIs), including asymptomatic bacteriuria, cystitis, pyelonephritis, urethritis, and urosepsis. While GBS neonatal disease has decreased, its prevalence in non-pregnant adults has risen. However, its role in UTIs among males and non-pregnant women is less documented. Objectives: This study aims to investigate the prevalence, clinical presentation, antibiotic susceptibility, and risk factors of GBS UTIs. Methods: Over 16 months, a prospective study included all patients diagnosed with GBS UTIs. Results: Among 6305 urine specimens tested, 2.1% (N = 134, 95% CI: 0.68% - 4.8%) were positive for GBS, with a notably higher prevalence among pregnant women (73%, N = 79). This prevalence rate significantly exceeded regional reports, as indicated by a z-score exceeding the critical value. Additionally, 50% of positive isolates were from antenatal patients, indicating pregnancy as a significant risk factor (P < 0.0001). All 134 GBS isolates exhibited sensitivity to penicillin, cefotaxime, ofloxacin, and vancomycin. Sensitivity to cotrimoxazole, erythromycin, and clindamycin was 80%, 95%, and 97%, respectively. Treatment varied by case severity. Uncomplicated cases (41.7% antenatal; 33.5% non-pregnant women and adults) received 3rd or 4th generation cephalosporins, while complicated cases (24.6%, N = 33) required intravenous vancomycin due to comorbidities like chronic kidney disease (CKD), renal calculi, diabetes, and obstetric complications. Conclusions: In conclusion, GBS UTIs predominantly affect females, particularly pregnant women, followed by those with chronic conditions like CKD and diabetes mellitus. Routine GBS culture and susceptibility testing are crucial in laboratories to ensure effective UTI management.