Use of the polymerase chain reaction for detection of Mycoplasma fermentans and Mycoplasma genitalium in the urogenital tract and amniotic fluid

Human Amnion Epithelial Cells (AECs) Respond to the FSL-1 Lipopeptide by Engaging the NLRP7 Inflammasome

Context and Objectives: Inflammation is the leading mechanism involved in both physiological and pathological rupture of fetal membranes. Our aim was to obtain a better characterization of the inflammasome-dependent inflammation processes in these tissues, with a particular focus on the nucleotide-binding oligomerization domain (NOD)–like receptor, pyrin domain containing protein 7 (NLRP7) inflammasome.

Methods: The presence of NLRP7 inflammasome actors [NLRP7, apoptosis-associated speck–like protein containing a CARD domain (ASC), and caspase-1] was confirmed by reverse transcriptase–polymerase chain reaction (RT-PCR) in human amnion and choriodecidua at the three trimesters and at term. The protein concentrations were then determined by enzyme-linked immunosorbent assay in term tissues, with or without labor. The presence of Mycoplasma salivarium and Mycoplasma fermentans in human fetal membranes was investigated using a PCR approach. Human amnion epithelial cells (AECs) were treated for 4 or 20 h with fibroblast-stimulating lipopeptide-1 (FSL-1), a M. salivarium–derived ligand. Transcripts and proteins quantity was then measured by RT–quantitative PCR and Western blotting, respectively. NLRP7 and ASC colocalization was confirmed by immunofluorescence. Western blots allowed analysis of pro–caspase-1 and gasdermin D cleavage.

Results: NLRP7, ASC, and caspase-1 transcripts were expressed in both sheets of human fetal membranes during all pregnancy stages, but only ASC protein expression was increased with labor. In addition, M. salivarium and M. fermentans were detected for the first time in human fetal membranes. NLRP7 and caspase-1 transcripts, as well as NLRP7, ASC, and pro–caspase-1 protein levels, were increased in FSL-1–treated AECs. The NLRP7 inflammasome assembled around the nucleus, and pro–caspase-1 and gasdermin D were cleaved into their mature forms after FSL-1 stimulation.

Conclusion: Two new mycoplasmas, M. salivarium and M. fermentans, were identified in human fetal membranes, and a lipopeptide derived from M. salivarium was found to induce NLRP7 inflammasome formation in AECs.

Intrapartum chlorhexidine vaginal irrigation and chorioamnion and placental microbial colonization

OBJECTIVES

To determine whether intrapartum chlorhexidine vaginal irrigation reduces microbial colonization of the chorioamnion or placenta.

METHODS

Secondary analysis was made of a randomized trial. Cultures for aerobic and anaerobic bacteria, Mycoplasma species and Ureaplasma urealyticum were performed using standard isolation techniques.

RESULTS

The placentas of 83 trial participants allocated to chlorhexidine and 93 allocated to placebo underwent evaluation. These two groups were statistically balanced for risk factors for infection. Aerobic bacteria were isolated from 47% of the chlorhexidine placentas vs. 51% of the placebo placentas (relative risk 0.9, 95% confidence interval 0.7-1.3), anaerobic bacteria from 30% and 35%, respectively (0.8, 0.5-1.3), group B streptococcus from 12% and 15% (0.8, 0.4-1.7), U. urealyticum from 18% and 29% (0.6, 0.4-1.1), Mycoplasma species from 6% and 11% (0.6, 0.2-1.6), and any organism from 57% and 67%, respectively (0.8, 0.7-1.1).

CONCLUSIONS

Intrapartum chlorhexidine vaginal irrigation was associated with non-significant reductions in the rates of placental microbial isolation.

Antibiotic use during pregnancy: how bad is it?

BACKGROUND

Our microbial companions (the "microbiota") are extremely important for the preservation of human health. Although changes in bacterial communities (dysbiosis) are commonly associated with disease, such changes have also been described in healthy pregnancies, where the microbiome plays an essential role in maternal and child health outcomes, including normal immune and metabolic function in later life. Nevertheless, this new understanding of the importance of the microbiome has not yet influenced contemporary clinical practice regarding antibiotic use during pregnancy.

DISCUSSION

Antibiotic treatment during pregnancy is widespread in Western countries, and accounts for 80 % of prescribed medications in pregnancy. However, antibiotic treatment, while at times lifesaving, can also have detrimental consequences. A single course of antibiotics perturbs bacterial communities, with evidence that the microbial ecosystem does not return completely to baseline following treatment. Antibiotics in pregnancy should be used only when indicated, choosing those with the narrowest range possible. Bacteria are essential for normal human development and, while antibiotic treatment during pregnancy has an important role in controlling and preventing infections, it may have undesired effects regarding the maternal and fetoplacental microbiomes. We expect that microbiota manipulation in pregnancy, through the use of probiotics and fecal microbiota transplantation, will be the subject of increasing clinical interest.

Distribution and perinatal transmission of bacterial vaginal infections in pregnant women without vaginal symptoms

BACKGROUND

We evaluated the distribution and vertical transmission of bacterial vaginal infections in asymptomatic pregnant women.

METHODS

We performed multiplex PCR on secretions collected on cervical swabs from pregnant women at over 36 weeks of gestation and on oral secretions collected from their neonates immediately after delivery. We detected sexually transmitted infections (STIs) with the following 6 species: Trichomonas vaginalis, Mycoplasma hominis, Mycoplasma genitalium, Chlamydia trachomatis, Neisseria gonorrhoeae, and Ureaplasma urealyticum.

RESULTS

Infectious agents were detected in 64 of 455 pregnant women (14.1%) and in 11 neonates (2.4%). The rate of vertical transmission was 17.2% and all the infectious agents detected in neonates were concordant with those found in their mothers. U. urealyticum was the most frequently detected in the maternal genitalia, followed by M. hominis. Women who were in labor for a longer period of time had a higher risk of vertically transmitting STI agents to their neonates.

CONCLUSIONS

Vertical transmission of bacterial STIs from mothers to their infants is possible at delivery and influenced by the duration of labor. STIs should be diagnosed in pregnant women to prevent vertical transmission from the mother to the infant at the time of delivery.

Complexity of the Mycoplasma fermentans M64 genome and metabolic essentiality and diversity among mycoplasmas

Recently, the genomes of two Mycoplasma fermentans strains, namely M64 and JER, have been completely sequenced. Gross comparison indicated that the genome of M64 is significantly bigger than the other strain and the difference is mainly contributed by the repetitive sequences including seven families of simple and complex transposable elements ranging from 973 to 23,778 bps. Analysis of these repeats resulted in the identification of a new distinct family of Integrative Conjugal Elements of M. fermentans, designated as ICEF-III. Using the concept of “reaction connectivity”, the metabolic capabilities in M. fermentans manifested by the complete and partial connected biomodules were revealed. A comparison of the reported M. pulmonis, M. arthritidis, M. genitalium, B. subtilis, and E. coli essential genes and the genes predicted from the M64 genome indicated that more than 73% of the Mycoplasmas essential genes are preserved in M. fermentans. Further examination of the highly and partly connected reactions by a novel combinatorial phylogenetic tree, metabolic network, and essential gene analysis indicated that some of the pathways (e.g. purine and pyrimidine metabolisms) with partial connected reactions may be important for the conversions of intermediate metabolites. Taken together, in light of systems and network analyses, the diversity among the Mycoplasma species was manifested on the variations of their limited metabolic abilities during evolution.

Diversity of microbes in amniotic fluid

Recent polymerase chain reaction (PCR)-based studies estimate the prevalence of microbial invasion of the amniotic cavity (MIAC) to be ≥30-50% higher than that detected by cultivation-based methods. Some species that have been long implicated in causing MIAC remain among the common invaders (e.g. Ureaplasma spp., Mycoplasma spp., Fusobacterium spp. Streptococcus spp., Bacteroides spp. and Prevotella spp.). Yet we now know from studies based on PCR of the 16S ribosomal DNA that cultivation-resistant anaerobes belonging to the family Fusobacteriaceae (particularly Sneathia sanguinegens, and Leptotrichia spp.) are also commonly found in amniotic fluid. Other diverse microbes detected by PCR of amniotic fluid include as-yet uncultivated and uncharacterized species. The presence of some microbial taxa is associated with specific host factors (e.g. Candida spp. and an indwelling intrauterine device). It appears that MIAC is polymicrobial in 24-67% of cases, but the potential role of pathogen synergy is poorly understood. A causal relationship between diverse microbes, as detected by PCR, and preterm birth is supported by types of association (e.g. space, time and dose) proposed as alternatives to Koch's postulates for inferring causality from molecular findings. The microbial census of the amniotic cavity remains unfinished. A more complete understanding may inform future research directions leading to improved strategies for preventing, diagnosing and treating MIAC.

Mycoplasma genitalium: from Chrysalis to multicolored butterfly

The history, replication, genetics, characteristics (both biological and physical), and factors involved in the pathogenesis of Mycoplasma genitalium are presented. The latter factors include adhesion, the influence of hormones, motility, possible toxin production, and immunological responses. The preferred site of colonization, together with current detection procedures, mainly by PCR technology, is discussed. The relationships between M. genitalium and various diseases are highlighted. These diseases include acute and chronic nongonococcal urethritis, balanoposthitis, chronic prostatitis, and acute epididymitis in men and urethritis, bacterial vaginosis, vaginitis, cervicitis, pelvic inflammatory disease, and reproductive disease in women. A causative relationship, or otherwise strong association, between several of these diseases and M. genitalium is apparent, and the extent of this, on a subjective basis, is presented; also provided is a comparison between M. genitalium and two other genital tract-orientated mollicutes, namely, Mycoplasma hominis, the first mycoplasma of human origin to be discovered, and Ureaplasma species. Also discussed is the relationship between M. genitalium and infertility and also arthritis in both men and women, as is infection in homosexual and immunodeficient patients. Decreased immunity, as in HIV infections, may enhance mycoplasmal detection and increase disease severity. Finally, aspects of the antimicrobial susceptibility and resistance of M. genitalium, together with the treatment and possible prevention of mycoplasmal disease, are discussed.

Mycoplasma genitalium: an emerging cause of sexually transmitted disease in women

Mycoplasma genitalium is an emerging sexually transmitted pathogen implicated in urethritis in men and several inflammatory reproductive tract syndromes in women including cervicitis, pelvic inflammatory disease (PID), and infertility. This comprehensive review critically examines epidemiologic studies of M. genitalium infections in women with the goal of assessing the associations with reproductive tract disease and enhancing awareness of this emerging pathogen. Over 27,000 women from 48 published reports have been screened for M. genitalium urogenital infection in high- or low-risk populations worldwide with an overall prevalence of 7.3% and 2.0%, respectively. M. genitalium was present in the general population at rates between those of Chlamydia trachomatis and Neisseria gonorrhoeae. Considering more than 20 studies of lower tract inflammation, M. genitalium has been positively associated with urethritis, vaginal discharge, and microscopic signs of cervicitis and/or mucopurulent cervical discharge in seven of 14 studies. A consistent case definition of cervicitis is lacking and will be required for comprehensive understanding of these associations. Importantly, evidence for M. genitalium PID and infertility are quite convincing and indicate that a significant proportion of upper tract inflammation may be attributed to this elusive pathogen. Collectively, M. genitalium is highly prevalent in high- and low-risk populations, and should be considered an etiologic agent of select reproductive tract disease syndromes in women.

Mycoplasma, Ureaplasma, and adverse pregnancy outcomes: a fresh look

Recent work on the Molicutes that associate with genital tract tissues focuses on four species that may be of interest in potential maternal, fetal, and neonatal infection and in contributing to adverse pregnancy outcomes. Mycoplasma hominis and Ureaplasma urealyticum have historically been the subject of attention, but Mycoplasma genitalis which causes male urethritis in addition to colonizing the female genital tract and the division of Ureaplasma into two species, urealyticum and parvum, has also added new taxonomic clarity. The role of these genital tract inhabitants in infection during pregnancy and their ability to invade and infect placental and fetal tissue is discussed. In particular, the role of some of these organisms in prematurity may be mechanistically related to their ability to induce inflammatory cytokines, thereby triggering pathways leading to preterm labor. A review of this intensifying exploration of the mycoplasmas in relation to pregnancy yields several questions which will be important to examine in future research.

Congenital and opportunistic infections: Ureaplasma species and Mycoplasma hominis

There is strong evidence from clinical and experimental animal studies that ureaplasmas can invade the amnionic sac and induce an inflammatory response resulting in chorioamnionitis, preterm labor and neonatal lung injury. The ability of Ureaplasma spp. and Mycoplasma hominis to cause pneumonia, bacteremia, and meningitis in newborns can no longer be questioned. The association of Ureaplasma spp. with bronchopulmonary dysplasia has been supported by the majority of observational studies, but proof of causality is still lacking. The availability of molecular diagnostic technologies has enabled the designation of the two Ureaplasma biovars as individual species, but additional work must be done to establish whether there is differential pathogenicity between the Ureaplasma spp. or among their respective serovars. Future investigations to prevent prematurity should be directed toward identification and localization of specific micro-organisms combined with targeted antibiotic trials to determine whether such interventions can improve long-term infant outcomes.

Mycoplasma genitalium among adolescent women and their partners

PURPOSE

Mycoplasma genitalium is a possible sexually transmitted pathogen and its study among the adolescent age group has been limited. In this longitudinal study, the epidemiology, natural history, and associated clinical findings of M. genitalium among adolescents in a primary care setting were explored.

METHODS

A sample of 383 young women (14-17 years of age) and 117 male partners provided sexual behavior data and urogenital samples for polymerase chain reaction testing to detect M. genitalium, Chlamydia trachomatis, and other sexually transmitted infections. Women were tested quarterly for up to 27 months and, during every other quarter, tested weekly. The presence of any signs or symptoms of infection among the female subjects was also documented.

RESULTS

Cumulatively, 13.6% (52/383) of women tested positive for M. genitalium. All women with M. genitalium, except one, were sexually experienced. M. genitalium was associated with number of sexual partners (p < .001) and C. trachomatis infection (p < .03). M. genitalium was more likely among male partners of M. genitalium-positive women (p < .02); 31.3% of untreated M. genitalium cases had infection lasting over 8 weeks. M. genitalium was not associated with the presence of clinical signs or symptoms of infection.

CONCLUSIONS

Findings support sexual transmissibility of M. genitalium and add to understanding of M. genitalium natural history and clinical findings.

Performance of the gen-probe transcription-mediated [corrected] amplification research assay compared to that of a multitarget real-time PCR for Mycoplasma genitalium detection

Mycoplasma genitalium (MG) can cause nongonococcal urethritis and is potentially associated with urethritis, endometritis, and cervicitis. Several assays have been developed to detect MG. Molecular amplification assays for organism detection can be problematic due to the potential for false-positive and false-negative results. Confirmatory testing is often required in these situations, requiring additional time and resources. Use of multigene targets could integrate both detection and verification at lower cost. Utilizing two targets, the MgPa adhesion gene and the 16S rRNA gene, a multitarget real-time (MTRT) PCR for the detection of MG was developed. Samples from patients attending sexually transmitted disease clinics were collected in duplicate. Urine samples from males (n = 286) and self-collected vaginal swabs from females (n = 321) were analyzed by MTRT PCR for MG and the Gen-Probe transcription-mediated [corrected] amplification (TMA) assay, which targets MG rRNA for detection (TMA-MG research use only). Utilizing the criteria of any two targets being positively amplified, the MTRT PCR had a sensitivity and specificity of 91.8% (101 positive samples/110 samples tested) and 99.5% (495/497), respectively, with a positive predictive value (PPV) of 98.1% (101/103) and a negative predictive value (NPV) of 98.2% (495/504). The Gen-Probe TMA-MG assay had a sensitivity, specificity, PPV, and NPV of 98.1% (108/110), 98.1% (488/497), 92.3% (108/117), and 99.5% (488/490), respectively. Comparison between the MTRT PCR and TMA-MG assay by kappa statistic analysis indicated that an overall kappa value was 0.941 (95% confidence interval, 0.907 and 0.976). Both assays demonstrated accuracy in the detection of MG from urine samples from male patients and self-collected vaginal swabs from female patients.

Proximal region of the gene encoding cytadherence-related protein permits molecular typing of Mycoplasma genitalium clinical strains by PCR-restriction fragment length polymorphism

Restriction fragment length polymorphism (RFLP) analysis of the PCR-amplified proximal region of the gene encoding cytadherence accessory protein P110 (MG192) revealed DNA sequence divergences among 54 Mycoplasma genitalium clinical strains isolated from the genitourinary tracts of women attending a sexually transmitted disease-related health clinic, plus one from the respiratory tract and one from synovial fluid. Seven of 56 (12.5%) strains exhibited RFLPs following digestion of the proximal region with restriction endonuclease MboI or RsaI, or both. No sequence variability was detected in the distal portion of the gene.

Cervicitis and Genitourinary Symptoms in Women Culture Positive for Mycoplasma genitalium

PROBLEM

Mycoplasma genitalium has been associated with male urethritis. We sought to relate M. genitalium to genitourinary signs and symptoms in women.

METHOD OF STUDY

We compared 26 culture-positive women (group 1), 257 additional polymerase chain reaction-positive women (group 2), and 107 negative control women. We used logistic regression to evaluate signs and symptoms, controlling for co-infections, pregnancy, age, and intervention group assignment.

RESULTS

Comparing group 1 with controls, we found significantly elevated odds ratios (ORs) for intermediate vaginal discharge (OR = 5.4; 95% confidence interval 1.01, 29.2) and action in response to discharge [3.9 (1.1, 13.5)]. Non-significant increases were observed for pathologic vaginal discharge [3.8 (0.78, 18.2)], pathologic dyspareunia [1.5 (0.25, 9.0)], vaginal odor [2.1 (0.75, 5.7)], and cervical mucopus [4.1 (0.74, 22.4)]. Group 2 results were similar, but showed no increase in cervical mucopus relative to controls.

CONCLUSION

Infection with M. genitalium in women is independently related to increased genitourinary symptomatology.

Mycoplasmas and ureaplasmas as neonatal pathogens

The genital mycoplasmas represent a complex and unique group of microorganisms that have been associated with a wide array of infectious diseases in adults and infants. The lack of conclusive knowledge regarding the pathogenic potential of Mycoplasma and Ureaplasma spp. in many conditions is due to a general unfamiliarity of physicians and microbiology laboratories with their fastidious growth requirements, leading to difficulty in their detection; their high prevalence in healthy persons; the poor design of research studies attempting to base association with disease on the mere presence of the organisms in the lower urogenital tract; the failure to consider multifactorial aspects of diseases; and considering these genital mycoplasmas only as a last resort. The situation is now changing because of a greater appreciation of the genital mycoplasmas as perinatal pathogens and improvements in laboratory detection, particularly with regard to the development of powerful molecular nucleic acid amplification tests. This review summarizes the epidemiology of genital mycoplasmas as causes of neonatal infections and premature birth; evidence linking ureaplasmas with bronchopulmonary dysplasia; recent changes in the taxonomy of the genus Ureaplasma; the neonatal host response to mycoplasma and ureaplasma infections; advances in laboratory detection, including molecular methods; and therapeutic considerations for treatment of systemic diseases.

Epidemiological study air disaster in Amsterdam (ESADA): study design

Background

In 1992, a cargo aircraft crashed into apartment buildings in Amsterdam, killing 43 victims and destroying 266 apartments. In the aftermath there were speculations about the cause of the crash, potential exposures to hazardous materials due to the disaster and the health consequences. Starting in 2000, the Epidemiological Study Air Disaster in Amsterdam (ESADA) aimed to assess the long-term health effects of occupational exposure to this disaster on professional assistance workers.

Methods/Design

Epidemiological study among all the exposed professional fire-fighters and police officers who performed disaster-related task(s), and hangar workers who sorted the wreckage of the aircraft, as well as reference groups of their non-exposed colleagues who did not perform any disaster-related tasks. The study took place, on average, 8.5 years after the disaster. Questionnaires were used to assess details on occupational exposure to the disaster. Health measures comprised laboratory assessments in urine, blood and saliva, as well as self-reported current health measures, including health-related quality of life, and various physical and psychological symptoms.

Discussion

In this paper we describe and discuss the design of the ESADA. The ESADA will provide additional scientific knowledge on the long-term health effects of technological disasters on professional workers.

Mycoplasma genitalium urethritis in men

Mycoplasma genitalium was first isolated from two men with non-gonococcal urethritis (NGU) and thereafter shown to produce urethritis in subhuman primates, inoculated intraurethrally. This mycoplasma has been detected significantly more often in patients with acute NGU, particularly in patients with non-chlamydial NGU, than in subjects without urethritis. The prevalence of M. genitalium-positive non-chlamydial NGU ranges from 18 to 46% of all non-chlamydial NGU cases. In addition, the persistence of M. genitalium in the urethra after antimicrobial chemotherapy is associated with persistence or recurrence of NGU. The various results reported to date tend to support the proposition that M. genitalium is a pathogen of NGU. M. genitalium is highly susceptible to tetracyclines, macrolides, and some new fluoroquinolones, but the clinical data on the chemotherapy in M. genitalium-positive NGU is extremely limited. Because of the possible association between the post-treatment presence of M. genitalium in the urethra and persistent or recurrent NGU, the eradication of this mycoplasma from the urethra is essential in the management of patients with M. genitalium-positive NGU. Further studies are required to establish the optimal chemotherapy for M. genitalium-positive NGU.

A novel polymerase chain reaction assay to detect Mycoplasma genitalium

AIMS

To design and validate a polymerase chain reaction (PCR) assay targeting the 16S rRNA gene of Mycoplasma genitalium.

METHODS

Primers were designed that were complementary to the 16S rRNA gene sequence of M genitalium. After optimisation of the reaction conditions, the PCR was tested against nine M genitalium strains, a dilution series of M genitalium DNA, and a panel of common microorganisms. The PCR was also challenged in parallel with a published assay against 54 urine specimens from men with urethritis.

RESULTS

The expected 341 bp product was produced on amplification of material from all M genitalium strains and from none of the other microorganisms tested. The lower limit of detection was 50 genome copies. The new assay detected M genitalium DNA in nine of 54 men with urethritis, in comparison with eight positive specimens detected with the alternative PCR.

CONCLUSIONS

This novel PCR targeting the M genitalium 16S rRNA gene has been optimised and now provides a sensitive and specific alternative or addition to the available MgPa gene targeting assays.

High prevalence of Mycoplasma genitalium in the lower genitourinary tract of women attending a sexually transmitted disease clinic in Paris, France

BACKGROUND

Previous studies have suggested that Mycoplasma genitalium is associated with cervicitis and may be a cause of pelvic inflammatory disease. This study attempted to investigate further the possible role of M genitalium in genital symptoms of women attending a sexually transmitted disease (STD) clinic.

GOAL

To determine the prevalence of and the association of clinical and microbiologic features with M genitalium in women presenting with genital symptoms.

STUDY DESIGN

Between April 1994 and June 1996 a prospective study of 170 consecutive women with abnormal vaginal discharge, with or without urethral itching, dysuria, or pelvic pain, was conducted at the STD clinic at Saint-Louis Hospital in Paris. Information was collected on each subject's characteristics, and a clinical vulvar, vaginal, and cervical examination was performed. Cervical, vaginal, and urethral samples were obtained to identify infecting organisms.

RESULTS

DNA of M genitalium was identified by polymerase chain reaction (PCR) at one or more genital sites in 65 women (38%; 95% CI, 31-46%) and was statistically more frequently detected in the vagina (39%) than in the cervix (21%) or urethra (28%) (P = 0.001 and 0.048, respectively). PCR inhibitors were detected in 17 specimens (4%). M genitalium was found in 6/14 (43%) positive for Chlamydia trachomatis, but no significant association between M genitalium and any demographic, clinical, or microbiologic data was noted in univariable or multivariable analysis.

CONCLUSION

This study indicates that M genitalium is frequently encountered in the female genital tract and is not associated with cervicitis or any particular clinical or microbiologic data.

Intrauterine infection and prematurity

Intrauterine infection is a major cause of premature labor with and without intact membranes. Intrauterine infection is present in approximately 25% of all preterm births and the earlier the gestational age at delivery, the higher the frequency of intra-amniotic infection. Microorganisms may also gain access to the fetus before delivery. A fetal inflammatory response syndrome elicited in response to microbial products is associated with the impending onset of preterm labor and also with multi-systemic organ involvement in the human fetus and a higher rate of perinatal morbidity. The most common microorganisms involved in intrauterine infections are Ureaplasma urealyticum, Fusobacterium species and Mycoplasma hominis. The role of Chlamydia trachomatis and viruses in preterm labor remain to be determined. Use of molecular microbiology techniques to diagnose intrauterine infection may uncover the role of fastidious microorganisms that have not yet been discovered. Antibiotic administration to patients with asymptomatic bacteriuria is associated with a significant reduction in the rate of preterm birth. However, such benefit has not been demonstrated for patients with bacterial vaginosis, or women who carry Streptococcus agalactia, Ureaplasma urealyticum or Trichomonas vaginalis. Antibiotic administration to patients with preterm premature rupture of membranes is associated with prolongation of pregnancy and a reduction in the rate of clinical chorioamnionitis and neonatal sepsis. The benefit has not been demonstrated in patients with preterm labor and intact membranes. Major efforts are required to determine why some women develop an ascending intrauterine infection and others do not and also what interventions may reduce the deleterious effect of systemic fetal inflammation.

Mycoplasma genitalium: another important pathogen of nongonococcal urethritis

PURPOSE

We reviewed findings on the pathogenic role of Mycoplasma genitalium in nongonococcal urethritis and the treatment of men with M. genitalium positive nongonococcal urethritis.

MATERIALS AND METHODS

We reviewed literature selected from peer reviewed journals listed in MEDLINE and from resources cited in those articles from 1967 to January 2001.

RESULTS

M. genitalium was first isolated from 2 men with nongonococcal urethritis and thereafter it was shown to cause urethritis in subhuman primates inoculated intraurethrally. This mycoplasma has been detected significantly more often in patients with acute nongonococcal urethritis, particularly in those with nonchlamydial nongonococcal urethritis, than in those without urethritis. The prevalence of M. genitalium positive nonchlamydial nongonococcal urethritis is 18.4% to 45.5% of all nonchlamydial nongonococcal urethritis cases. In addition, the persistence of M. genitalium in the urethra after antimicrobial chemotherapy is associated with persistent or recurrent nongonococcal urethritis. M. genitalium is highly susceptible to tetracycline, macrolide and some new fluoroquinolones. The regimen of 100 mg. doxycycline orally twice daily for 7 days, which is recommended for chlamydial nongonococcal urethritis, seems to be effective for M. genitalium positive nongonococcal urethritis, although clinical data to substantiate this regimen are limited.

CONCLUSIONS

The various results reported to date tend to support the proposition that M. genitalium is a pathogen of nongonococcal urethritis. However, currently diagnostic methods for this important mycoplasma are not available in clinical practice. Because of the possible association of the posttreatment presence of M. genitalium in the urethra with persistent or recurrent nongonococcal urethritis, eradication of this mycoplasma from the urethra is essential for managing M. genitalium positive disease. However, clinical data on treating M. genitalium positive nongonococcal urethritis are extremely limited. Thus, further studies are required to develop new diagnostic methods that would be available in clinical settings and establish a new treatment algorithm for nongonococcal urethritis, including M. genitalium positive disease.

Midtrimester vaginal Mycoplasma genitalium in women with subsequent spontaneous preterm birth

OBJECTIVE

We sought to determine the midtrimester prevalence of Mycoplasma genitalium in women who had subsequent spontaneous preterm birth.

STUDY DESIGN

In a prospective study of lower genital tract infections, we identified 127 women who subsequently had spontaneous preterm birth. Vaginal samples were obtained between 21 and 25 weeks' gestation for pH, for bacterial vaginosis Gram stain, and cultures that yielded Chlamydia trachomatis, Neisseria gonorrhoeae, and Trichomonas vaginalis. M genitalium was identified by using validated polymerase chain reaction (PCR) primers, and the results were compared to pregnancy outcomes.

RESULTS

Of 124 women with spontaneous preterm births, only five (3.9%) had PCR assays positive forM genitalium. The mean +/- SD delivery gestational age was similar for women with a positive PCR (34.6 +/- 2.2 weeks) and a negative PCR (34.0 +/- 2.7 weeks) (P =.62). None of the women with positive PCR results tested positive for any other sexually transmitted disease, whereas 36 (30%) women with negative PCR results tested positive.

CONCLUSIONS

The occurrence of M genitalium in the vagina at midtrimester is infrequent in women with subsequent spontaneous preterm birth.

Detection of Mycoplasma fermentans in healthy students and patients with congenital immunodeficiency

OBJECTIVES

To determine the prevalence of M. fermentans at different anatomical sites in healthy subjects and in patients with congenital immunodeficiency, and to determine whether haematogenous invasion occurs among the latter.

METHODS

A polymerase chain reaction (PCR) assay was used to detect M.fermentans in throat swabs and urine specimens from healthy students, and from patients with congenital immunodeficiency. Peripheral blood mononuclear cells (PBMCs) from the latter group were also tested.

RESULTS

Sixty-two students provided throat swabs, of which 11 (18%) were M. Jermentans-positive; 46 provided urine specimens, of which eight (17%) were positive. Of the 45 students who provided both throat and urine specimens, 12 (27%) had M. fermentans-positive samples; four in the throat and urine, four in the throat only and four in the urine only. Nineteen of the 20 patients with congenital immunodeficiency provided throat swabs, of which one (5%) was M. fermentans-positive; 19 also provided urine specimens, of which three (16%) were positive. All of the immunodeficient patients provided a PBMC sample, but none was positive.

CONCLUSION

M. fermentans occurred frequently at mucosal sites in a healthy population and in subjects with congenital immunodeficiency. However, such a deficiency did not lead to overt haematogenous invasion.

Mycoplasma fermentans DNA is infrequently detected in urine specimens from renal transplant recipients

Mycoplasma fermentans is a likely causative agent of HIV-associated nephropathy. In a pilot study, M. fermentans DNA was detected with polymerase chain reaction (PCR) in urine samples from renal allograft recipients; nine (39.1%) out of 23 renal allograft recipients (most of whom had chronic allograft rejection) and none of the 20 controls, were infected with M. fermentans. A cross-sectional study was conducted to investigate the prevalence of M. fermentans in urine samples from renal allograft recipients. Midstream urine samples were centrifuged at 13,000 x g, purified with QIAamp and tested with PCR using RW004/RW005 and an internal control to screen for the presence of inhibitors. Of the 264 participants recruited, 263 completed the questionnaire (172 men, 92 women); 53 had chronic renal allograft rejection, 106 had chronic renal dysfunction without rejection, 69 had a normal renal allograft for more than 3 months and 35 had a renal allograft for less than 3 months. All urine samples yielded positive results for the internal control. Mycoplasma fermentans DNA was detected once i prospectively collected urine samples. The only individual infected with M. fermentans was also seropositive for HIV-1. This study demonstrates that M. fermentans can be at most sporadically detected in urine from patients living with a renal allograft but is not implicated in chronic rejection of allograft.

The ftsZ gene as a tool for detection of Mycoplasma fermentans

Mycoplasma fermentans was reported as a common contaminant of cell cultures, and was shown to either induce or suppress several immunological functions. A strain of M. fermentans was recently isolated from a mouse T-lymphoma cell line, which differs from other M. fermentans strains by its growth characteristics and was designated (in the authors' records) as strain 609. Using the differential display technique (DD), a differentially expressed gene that was identified as the M. fermentans 609 ftsZ gene was isolated. Comparison of the nucleotide sequence of the M. fermentans 609 ftsZ gene to other ftsZ genes showed a 98% homology with Mycoplasma fermentans strain K7 and approximately 50% homology with Mycoplasma pulmonis and Mycoplasma genitalium. Comparison of the putative amino acid sequences of the FtsZ proteins showed similar homology. A polymerase chain reaction (PCR) assay to detect the presence of this ftsZ gene was established; it is a fast and convenient assay to detect infection of cells by the M. fermentans species. This work demonstrates that: (i) DD can be used as a useful technique to identify and isolate mycoplasmal genes from infected cells; and (ii) the ftsZ gene can be a useful marker to distinguish between different species of mycoplasma.