While the association of
U. urealyticum with the urogenital tract infections is well established, the role of
U. parvum in these infections is still insufficient. Moreover, the presence of
U. parvum in the lower urogenital tract of many healthy nonpregnant women complicates an understanding of the potential role of these microorganisms in adverse outcomes of pregnancy and reproductive system disorders. In the study we have compared the prevalence of
U. parvum and
U. urealyticum in pairs of specimens, i.e., vaginal swabs and Douglas’ pouch fluid samples obtained during the laparoscopy from consecutive 40 women with no symptoms of the urogenital tract infection. Both these species,
U. parvum and
U. urealyticum were detected in Douglas’ pouch fluid samples in about 60 % of women carrying ureaplasmas in the lower urogenital tract, confirming that cervicovaginal colonization can lead to the direct ascent of ureaplasmas to the sterile upper reproductive tract. To our knowledge this is the first report on the detection of
U. parvum in Douglas’ pouch fluid samples from women without any signs of the upper genital tract infection. The findings of the study indicated that
U. parvum, similarly to
U. urealyticum, can produce asymptomatic infection of the upper genital tract in women. The presence of these organisms in the sterile part of the genital tract may induce long-lasting subacute inflammation that may be the cause of the upper genital tract disorders e.g., infertility. Zhu et al. [
14] in the study of pathogenicity of
U. parvum serotypes 1, 3, and 6, and
U. urealyticum serotypes 4 and 8 for BALB/c female mice showed that all these serotypes caused morphological changes of the external genitalia associated with infiltration by inflammatory cells and increased tumor necrosis factor-α (TNF-α) expression. Similarly, Shimizu et al. [
15] indicated that
U. parvum lipoproteins activated nuclear factor NF-κB thus inducing the synthesis of tumor necrosis factor alpha (TNF-α) in mouse peritoneal macrophages. Allam et al. [
6] in their study on bladder tissue from animals actively colonized by
U. parvum demonstrated significant alterations in actin binding proteins that may influence cell signaling cascades regulating cell motility, differentiation, apoptosis, and inflammation. Moreover, they have shown in a rats experimentally infected with
U. parvum three clinical outcomes of infection, i.e., clearance of infection within 2 weeks in one-third of animals, then asymptomatic infection and acute, complicated infection of bladder associated with the presence of ureaplasmas within bladder submucosa. Their study pointed out that the effect of infections caused by
U. parvum depends on the host-associated factors. Most localized to the lower urogenital tract infections caused by ureaplasmas characterize asymptomatic or subclinical course due to limited immune response. On the other hand, there are several reports on the disseminated, acute ureaplasmal infections that occur mostly among neonates and immunosuppressed individuals, indicating the significance of the host immune response in the clinical outcome of these infections [
16‐
19]. All these reports confirmed pathogenicity of
U. parvum for the host cells and indicated that the occurrence of these organisms in the genitourinary tract is associated with inflammatory response. Demonstrated in the study, the presence of
U. parvum and
U. urealyticum in the Douglas’ pouch, even asymptomatic, implies that immune response against these organisms seem to be inevitable and may produce chronic inflammation with subsequent development of abnormalities within upper genitourinary tract of women.
In addition, in the study we compared the prevalence of both,
U. parvum and
U. urealyticum in the specimens obtained from fertile and infertile women. The results showed that the upper genitourinary tract infection with
Ureaplasma spp. was more common among infertile than fertile women what is in concordance with Dhawan et al. [
13] who have shown the predominance of
U. parvum serovar 3/14 in patients with genital infections and infertility.
The results of the study also raised the problem of treating ureaplasma-positive individuals. Taking into consideration pathogenic potential of these bacteria, and the fact that most infections caused by Ureaplasma spp. are mild or unnoticeable, and that the colonization of the lower genitourinary tract with ureaplasmas is common, general rules should be established.
Since many investigators have shown using quantitative techniques that the degree of colonization with
Ureaplasma spp. is correlated with clinical presentation and adverse outcomes [
4,
20], the decision whether the presence of ureaplasmas in the genitourinary tract should be treated depends on the specimen and the concentration of ureaplasmas in the specimen. In case of specimens obtained from the lower genitourinary tract colonized by normal flora, culture or/and commercially available diagnostic kits should be used instead of sensitive molecular methods. Many available screening tests allow to detect ureaplasmas and, what is more important, to establish their load. The concentration of ureaplasmas in the specimen from the lower genitourinary tract amounting ≥10
4 organisms per ml is commonly accepted as the load indicating an infection that should be treated with antimicrobials. Lower concentrations (<10
4 organisms per ml) of ureaplasmas in all specimens from the lower genitourinary tract are considered colonization that does not need treatment. In case of specimens obtained from the upper genitourinary tract, the load of ureaplasmas is not as important as in case of specimens from the lower genitourinary tract as the occurrence of ureaplasmas in the sterile body sites is always considered an infection that should be treated. Thus, the detection of ureaplasmas in all specimens obtained from the upper genitourinary tract should rely on sensitive molecular methods that allow detecting even low concentrations of ureaplasmas within specimens as well as enabling their identification to the species level. Moreover, treatment should include infection in both, men and women and their sexual contacts.