Beyond Standard Culture: Diagnostic Value of Ureaplasma and Chlamydia in Women with UTI Symptoms

ABSTRACT

Objective

This study aimed to determine the prevalence, diagnostic contribution, and antimicrobial susceptibility patterns of atypical sexually transmitted pathogens—Ureaplasma urealyticum (U. urealyticum) and Chlamydia trachomatis (C. trachomatis)—in sexually active women presenting with urinary tract infection symptoms, particularly in cases with pyuria and negative standard cultures.

Methods

A total of 185 sexually active women aged ≥18 years presenting with lower urinary tract symptoms and pyuria (≥10 WBC/ high-power field were retrospectively evaluated. Patients with fever or flank pain suggesting pyelonephritis were excluded. Conventional urine culture (significant growth ≥10⁵ colony-forming unit (CFU)/mL), colorimetric culture for U. urealyticum (≥10⁴ CCU/mL considered clinically significant), and multiplex real-time polymerase chain reaction for C. trachomatis were performed. Antimicrobial susceptibility of U. urealyticum was assessed using both colorimetric testing and broth microdilution.

Results

Conventional urine culture was positive in 62/185 (33.5%) patients, with Escherichia coli detected in 41/185 (22.2%). Among the 123 culture-negative patients, 60 (48.8%) tested positive for atypical pathogens. Overall prevalence rates were 31.4% for U. urealyticum, 17,8% for C. trachomatis, and 1.6% for co-infection, following correction of previous reporting errors. The addition of molecular testing increased the diagnostic yield from 33.5% to 65.9%. U. urealyticum demonstrated the highest susceptibility to minocycline and levofloxacin (86.7%), followed by erythromycin (83.3%) and tetracycline (79.6), whereas marked resistance to clindamycin (77.3%) was noted.

Conclusions

Atypical pathogens are prevalent and frequently underdiagnosed causes of lower urinary tract symptoms in women with negative standard urine cultures. Integrating molecular and specialized culture methods substantially enhances diagnostic accuracy and enables targeted therapy. Tetracyclines and macrolides appear to be the most appropriate empirical treatment options in settings with a high prevalence of U. urealyticum.

Keywords:

Urinary tract infection, Ureaplasma urealyticum, Chlamydia trachomatis, atypical pathogens, molecular testing, antimicrobial susceptibility, cystitis