Persistent Mycoplasma genitalium Infection of Human Endocervical Epithelial Cells Elicits Chronic Inflammatory Cytokine Secretion

Abstract

genitalium has yet to be defined, significant associations exist between M. genitalium and cervicitis, pelvic inflammatory disease (PID), and tubal infertility (23,25,30). Among female reproductive tract tissues, M. genitalium DNA has been detected in specimens from the vagina, endocervix, endometrium, and the fallopian tubes, suggesting that, after sexual transmission, the organism can disseminate from the lower to the upper tract. Similarly, outbred mice inoculated vaginally showed time-dependent ascension of M. genitalium from the vagina to the cervix, followed by detection in the uterus, fallopian tubes, and ovaries (27). Therefore, the cervix appears to be either a primary or transient target of infection. Considering the clinical associations of M. genitalium with urogenital inflammation, it remains imperative to investigate the basic mechanisms of mucosal infection and disease induced by this organism.Among male and female reproductive tract syndromes for which M. genitalium has been implicated, all could be attributed to long-term colonization of the urogenital tract, which we refer to here as "persistence." Consistent with the ability to survive longterm in urogenital tissues and similar to other sexually acquired urogenital pathogens, it is hypothesized that M. genitalium has evolved specific mechanisms to evade the host immune system. Indeed, persistent cervical infection has been observed in several clinical studies (4,6,10,13) and has been associated with chronic symptoms (4). Persistent infection by M. genitalium is likely mediated, at least in part, by recombinational variation of genes encoding surface-exposed antigens (13,14,22) and through intracellular localization (2,7,17,26,31). Despite these mechanisms for avoiding the host's immune system, M. genitalium appears to induce a significant inflammatory response, as demonstrated with epidemiologic associations with urogenital disease (25, 30) and the observation that human ecto-and endocervical epithelial cells respond to acute infection with proinflammatory cytokine secretion (26). A link to human immunodeficiency virus (HIV) infection has been observed (29) since cervicitis caused by M. genitalium occurs more often in HIV-positive subjects (20) and, importantly, since M. genitalium persists longer in these women (6). In addition, high M. genitalium burden is correlated with increased HIV shedding from the cervix (24). Collectively, under-

Mycoplasma genitalium Infection Is Associated with Microscopic Signs of Cervical Inflammation in Liquid Cytology Specimens

“…The MG190 TaqMan PCR assay was described previously (30). In the current study, we evaluated performance of the MG191 assay with liquid cytology specimens.…”

“…Real-time PCR was performed using the CFX96 real-time PCR detection system (Bio-Rad Laboratories, Inc.) with twostep cycling parameters as described previously (30). Samples with a positive result using the MG190 TaqMan PCR assay were confirmed using a PCR assay targeting a conserved region of mgpB using primers 1F and 1R (16) with SYBR green detection chemistry.…”

“…To detect and enumerate M. genitalium organisms, we employed a real-time quantitative PCR (qPCR) assay targeting a 92-bp region of the MG190 (mgpA) gene (30) with the following reaction conditions: 12.5 l of iQ Supermix (Bio-Rad Laboratories, Inc., Hercules, CA), 1.0 l of forward primer (190F; 5 M stock), 1.0 l of reverse primer (190R3; 5 M stock), 1.0 l of the MG190 TaqMan probe (MG190P; 5 M stock), and 5 l of the DNA template. Real-time PCR was performed using the CFX96 real-time PCR detection system (Bio-Rad Laboratories, Inc.) with twostep cycling parameters as described previously (30).…”

Extensive Variation and Rapid Shift of the MG192 Sequence in Mycoplasma genitalium Strains from Patients with Chronic Infection

“…Additionally, there are increasing numbers of studies suggesting that M. genitalium increases the risk of HIV-1 acquisition and/or transmission (2)(3)(4). Like other pathogenic mycoplasmas, M. genitalium is capable of causing chronic infections, as has been documented in cultured human endocervical epithelial cells (5), in animal models (6,7), in men with NGU (8,9), and in women with cervicitis (10). The mechanisms for persistence remain poorly understood.…”

Experimental Infection of Pig-Tailed Macaques (Macaca nemestrina) with Mycoplasma genitalium

“…Furthermore, in vitro experiments demonstrated that adherent M. genitalium cultures decrease the integrity of endocervical cells, increasing the passage of HIV through epithelial barriers (31), which provides a molecular explanation for the increased risk of HIV acquisition in M. genitaliuminfected women (10,11). In vitro epithelial cell models revealed that M. genitalium infection induces host defense and inflammation pathways (32,33), as does a purified fragment of the immunogenic lipoprotein MG309 (34). A serine/threonine phosphatase (MG207) has been implicated in cytotoxicity to culture cells (35), and a peptide methionine sulfoxide reductase (MsrA) promotes survival in vivo in the lungs of hamsters (36).…”