Chlamydia trachomatis Testing Sensitivity in Midstream Compared With First-Void Urine Specimens

With great interest we read the article of Mangin et al. As the authors state, the possibility of testing for Chlamydia trachomatis and uropathogens on a single urine specimen might provide a valuable case finding tool to improve detection of C. trachomatis in women with urinary symptoms. However, to assess the clinical consequences of this approach, knowledge on the prevalence of C. trachomatis in women with urinary symptoms is needed, as the authors also mention.

As part of a study we performed on diagnosis of urinary tract infections (UTIs)(1), otherwise healthy, non-pregnant women who contacted their family physician with painful and/or frequent micturition for no longer than seven days, collected urine in sterile containers. No collection instructions (e.g. first-void or midstream) were given. The urine samples were tested for uropathogens (by urinalysis and urine culture), Neisseria gonorrhoeae and Chlamydia trachomatis (by a combined DNA assay (CE-IVD Presto CT-NG Assay, Goffin Molecular Technologies, Beek, The Netherlands)). After one week we recorded symptoms and antibiotic use.

Urine samples of 74 women were tested (mean age: 36 yrs (interquartile range 25-46); number of patients with at least 1,000 colony -forming units per milliliter (CFU/mL) of a uropathogen: 38 (51%)). All samples were negative for N. gonorrhoeae. Samples from two Caucasian women were positive for C. trachomatis, indicating a prevalence of 2.7% (95%CI 0.7-9.3%). One of these two women was 62 years of age and married, lived in a rural area, had no uropathogen in her urine culture, and reported improvement of symptoms after one week without having used an antibiotic. The other woman was 22 years of age, lived in an urban area, had Escherichia coli in her urine culture (between 10,000 and 100,000 CFU/mL), and reported cure of symptoms after one week, after having used nitrofurantoin for five days. Both women had positive nitrite and leukocyte esterase test results on urinalysis.

In conclusion, in a primary care sample of 74 women with painful and/or frequent micturition for no longer than seven days, two women tested positive for C. trachomatis, indicating a prevalence between 1 and 9 percent. One case did not have any known risk factors, and both cases tested positive on urinalysis. This implies that physicians should keep the possibility of C. trachomatis infection in mind in all women with UTI symptoms, even if a UTI is diagnosed. We support the authors' recommendation to perform larger prevalence studies on C. trachomatis in women with UTI symptoms.

(1) Knottnerus BJ, Bindels PJ, Geerlings SE, Moll van Charante EP, Ter Riet G. Optimizing the diagnostic work-up of acute uncomplicated urinary tract infections. BMC Fam Pract 2008;9:64.

Competing interests:   None declared