Microbiological and histopathological findings in acute pelvic inflammatory disease

Bacterial Vaginosis and Post-Operative Pelvic Infections

Bacterial vaginosis (BV) represents a condition in which the normal protective Lactobacilli, especially those that produce H₂O₂, are replaced by high quantities of facultative anaerobes, leading to gynecologic and obstetric post-operative complications. BV is an important cause of obstetric and gynecological adverse sequelae and it could lead to an increased risk of contracting sexually transmitted infections such as gonorrhea, genital herpes, Chlamydia, Trichomonas, and human immunodeficiency virus. Herein, we reviewed bacterial vaginosis and its association with post-operative pelvic infections. In Obstetrics, BV has been associated with increased risk of preterm delivery, first-trimester miscarriage in women undergoing in vitro fertilization, preterm premature rupture of membranes, chorioamnionitis, amniotic fluid infections, postpartum and postabortal endomyometritis as well as postabortal pelvic inflammatory disease (PID). In gynecology, BV increases the risk of post-hysterectomy infections such as vaginal cuff cellulitis, pelvic cellulitis, pelvic abscess, and PID. BV is often asymptomatic, can resolve spontaneously, and often relapses with or without treatment. The American College of Obstetricians and Gynecologists recommends testing for BV in women having an increased risk for preterm delivery. Women with symptoms should be evaluated and treated. Women with BV undergoing gynecological surgeries must be treated to reduce the frequency of post-operative pelvic infections. Metronidazole and clindamycin are the mainstays of therapy. Currently, there is no consensus on pre-surgery screening for BV; decisions are made on a case-by-case basis.

Bacterial Vaginosis and Behavioral Factors Associated With Incident Pelvic Inflammatory Disease in the Longitudinal Study of Vaginal Flora

BACKGROUND

Pelvic inflammatory disease (PID) leads to long-term reproductive consequences for cisgender women. Bacterial vaginosis (BV) and behavioral factors may play a role in PID pathogenesis. We assessed associations between BV, behavioral factors, and incident PID.

METHODS

We analyzed participants (N = 2956) enrolled in the National Institutes of Health Longitudinal Study of Vaginal Flora, a cohort of nonpregnant cisgender women followed quarterly for 12 months. PID was defined by at least 1 of the following: cervical motion tenderness, uterine tenderness, or adnexal tenderness (160 cases). We tested associations between BV (measured using Nugent and Amsel criteria) and PID at the subsequent visit. Sociodemographic factors, sexual behaviors, and Chlamydia trachomatis (CT), untreated at baseline and concurrent with BV, were covariates in Cox proportional hazards models. Adjusting for the few Neisseria gonorrhoeae and Trichomonas vaginalis cases did not alter results.

RESULTS

In multivariable modeling, Nugent-BV (adjusted hazard ratio [aHR], 1.53 [95% confidence interval {CI}, 1.05-2.21]), symptomatic Amsel-BV (aHR, 2.15 [95% CI, 1.23-3.75]), and vaginal douching (aHR, 1.47 [95% CI, 1.03-2.09]) were associated with incident PID.

CONCLUSIONS

BV was associated with incident PID in a large prospective cohort, controlling for behavioral factors and sexually transmitted infections (STIs). Larger studies on how BV, STIs, behaviors, and host responses interactively affect PID risk are needed.

[Diagnosis of pelvic inflammatory disease: Clinical, paraclinical, imaging and laparoscopy criteria. CNGOF and SPILF Pelvic Inflammatory Diseases Guidelines]

The objective of this literature review is to update the recommendations for clinical practice about the diagnosis of pelvic inflammatory disease (PID), microbiologic diagnosis excluded. An adnexal pain or cervical motion tenderness are the signs that allow a positive diagnosis of PID (LE2). Associated signs (fever, leucorrhoea, metrorrhagia) reinforce clinical diagnosis (LE2). In a woman consulting for symptoms compatible with PID, a pelvic clinical examination is recommended (grade B). In cases of suspected PID, hyperleukocytosis associated with a high C-reactive protein suggests a complicated PID or a differential diagnosis such as acute appendicitis (LE3). The absence of hyperleukocytosis or normal CRP does not rule out the diagnosis of PID (LE1). When PID is suspected, a blood test with a blood count and a CRP test is recommended (grade C). Pelvic ultrasound scan does not contribute to the positive diagnosis of uncomplicated PID because it is insensitive and unspecific (LE3). However, ultrasound scan is recommended to look for signs of complicated PID (polymorphic collection) or differential diagnosis (grade C). Waiting for an ultrasound scan to be performed should not delay the start-up of antibiotic therapy. In case of diagnostic uncertainty, an abdominal-pelvic CT scan with contrast injection is useful for differential diagnosis of urinary, digestive or gynaecological origin (LE2). Laparoscopy is not recommended for the unique purpose of the positive diagnosis of PID (grade B).

[Treatment of uncomplicated pelvic inflammatory disease: CNGOF and SPILF Pelvic Inflammatory Diseases Guidelines]

This review of the treatment of uncomplicated pelvic inflammatory disease (PID) focuses on the susceptibility profile of the main microbiological causes as well as on the advantages and inconvenients of relevant antibiotics. As bacterial resistance is expanding in the community, the rules of adequate antibiotic prescribing are integrated in the treatment proposals. While the pathogenic role of anaerobic bacteria in uncomplicated PID remains discussed, the choice to provide anaerobes coverage is proposed. Thus, the antibiotic treatment has to cover Chamydia trachomatis, Neisseria gonorrhoeae, anaerobes as well as Streptococcus spp, gram negative bacteria and the ermerging Mycoplasma genitalium. On the basis of published trials and good practice antibiotic usage, the ceftriaxone-doxycycline-metronidazole combination has been selected as the first line regimen. Fluoroquinolones (moxifloxacin alone, or levofloxacin or ofloxacin combined with metronidazole) are proposed as alternatives because of their ecological impact and their side effects leading to restricted usage. When fluoroquinolone are used, ceftriaxone should be added in case of possible sexually transmitted infection. When detected, M. genitalium should be treated by moxifloxacin. Moreover, this review highlights the need to better describe the microbiological epidemiology of uncomplicated PID in France or Europe.

A Comparison of the Use of Papanicolaou-stained Cervical Cytological Smears with Gram-stained Vaginal Smears for the Diagnosis of Bacterial Vaginosis in Early Pregnancy

Our objective is to compare the efficacy of using Papanicolaou (PAP)-stained cervical cytology smears with a standardized method of interpreting Gram-stained vaginal smears for the diagnosis of bacterial vaginosis (BV) in pregnancy.

High vaginal smears were Gram-stained and examined by a single observer to characterize 3 grades of vaginal flora and diagnose BV. Cervical smears were PAP-stained and examined for characteristic patterns of vaginal flora including evidence of BV by either a number of cytotechnicians or a single cytopathologist. The results of the 2 methods were compared. Seven hundred and forty-seven women attending an antenatal clinic in a district general hospital who consented to have a smear of vaginal secretions and cervical cytology in early pregnancy. The main outcome measure is the diagnosis of BV by different methods in a pregnant population.

Compared with the Gram-stain method for the diagnosis of BV, there was good agreement between PAP-stain interpretation by a single observer but the agreement was not as good with PAP-stain interpretation by multiple cytotechnicians. When the grades were consolidated to normal (grade I) and abnormal flora (grades II and III), compared to Gram-stained smears, PAP cytology undertaken by several cytotechnicians had a sensitivity of 80.7% and a specificity of 90.7%. The sensitivity and specificity increased to 87% and 97%, respectively, when the PAP-stained smears were read by a single cytopathologist. Using kappa scores, only those readings made by a single cytopathologist were reliable.

The setting in a cytopathology laboratory comprises multiple cytotechnicians, so that PAP-stain analysis of vaginal smears for the diagnosis of BV is likely to provide results which are less reliable than those obtained by Gram staining. The latter should be the first choice and every effort should be made to set up this service.

CXCL10, CXCL11, HLA-A and IL-1β are induced in peripheral blood mononuclear cells from women with Chlamydia trachomatis related infertility

Chlamydia trachomatis infections can result in the development of serious sequelae such as pelvic inflammatory disease and tubal infertility. In this study, peripheral blood mononuclear cells from women who were undergoing or had recently undergone IVF treatment were cultured ex vivo with C. trachomatis to identify the immune responses associated with women who had serological evidence of a history of Chlamydia infection. Cytokines secreted into the supernatant from the cultures were measured using ELISA, and the level of IL-1β was found to be significantly higher in Chlamydia positive women than Chlamydia negative women. qRT-PCR analysis of the expression of 88 immune-related genes showed trends towards an upregulation of CXCL10, CXCL11 and HLA-A in Chlamydia positive women compared with Chlamydia negative women. These findings support that some women launch a more marked proinflammatory response upon infection with C. trachomatis and this may be associated with why C. trachomatis induces infertility in some infected women.

Menstrual Hygiene Practices, WASH Access and the Risk of Urogenital Infection in Women from Odisha, India

Menstrual hygiene management (MHM) practices vary worldwide and depend on the individual’s socioeconomic status, personal preferences, local traditions and beliefs, and access to water and sanitation resources. MHM practices can be particularly unhygienic and inconvenient for girls and women in poorer settings. Little is known about whether unhygienic MHM practices increase a woman’s exposure to urogenital infections, such as bacterial vaginosis (BV) and urinary tract infection (UTI). This study aimed to determine the association of MHM practices with urogenital infections, controlling for environmental drivers. A hospital-based case-control study was conducted on 486 women at Odisha, India. Cases and controls were recruited using a syndromic approach. Vaginal swabs were collected from all the participants and tested for BV status using Amsel’s criteria. Urine samples were cultured to assess UTI status. Socioeconomic status, clinical symptoms and reproductive history, and MHM and water and sanitation practices were obtained by standardised questionnaire. A total of 486 women were recruited to the study, 228 symptomatic cases and 258 asymptomatic controls. Women who used reusable absorbent pads were more likely to have symptoms of urogenital infection (AdjOR=2.3, 95%CI1.5-3.4) or to be diagnosed with at least one urogenital infection (BV or UTI) (AdjOR=2.8, 95%CI1.7-4.5), than women using disposable pads. Increased wealth and space for personal hygiene in the household were protective for BV (AdjOR=0.5, 95%CI0.3-0.9 and AdjOR=0.6, 95%CI0.3-0.9 respectively). Lower education of the participants was the only factor associated with UTI after adjusting for all the confounders (AdjOR=3.1, 95%CI1.2-7.9). Interventions that ensure women have access to private facilities with water for MHM and that educate women about safer, low-cost MHM materials could reduce urogenital disease among women. Further studies of the effects of specific practices for managing hygienically reusable pads and studies to explore other pathogenic reproductive tract infections are needed.

Pelvic inflammatory disease: identifying research gaps--proceedings of a workshop sponsored by Department of Health and Human Services/National Institutes of Health/National Institute of Allergy and Infectious Diseases, November 3-4, 2011

In November 2011, the National Institutes of Health convened a workshop of basic researchers, epidemiologists, and clinical experts in pelvic inflammatory disease to identify research gaps hindering advances in diagnosis, treatment, and prevention. This article summarizes the presentations, discussions, and conclusions of this group and highlights significant controversies that reveal aspects of pelvic inflammatory disease research that would most greatly benefit from the application of newer molecular, immunologic, and radiologic techniques. Multiple limitations to performing new clinical trials exist; however, emerging data from ongoing clinical trials will add to the current body of knowledge regarding prevention and treatment strategies. In addition, use of established health care databases could serve as a valuable tool for performance of unbiased epidemiologic outcome studies.

Bacterial vaginosis-associated bacteria in men: association of Leptotrichia/Sneathia spp. with nongonococcal urethritis

BACKGROUND

Approximately 45% of nongonococcal urethritis cases have no identified etiology. Novel bacteria recently associated with bacterial vaginosis (BV) in women may be involved. We evaluated the association of idiopathic nongonococcal urethritis and 5 newly described BV-associated bacteria (BVAB).

METHODS

Heterosexual men 16 years or older attending a sexually transmitted disease clinic in Seattle, Washington, from May 2007 to July 2011 and negative for Chlamydia trachomatis, Neisseria gonorrhoeae, Trichomonas vaginalis, Mycoplasma genitalium, and Ureaplasma urealyticum-biovar2 were eligible. Cases had urethral discharge or 5 or more polymorphonuclear leukocytes per high-power field in urethral exudates. Controls had no urethral discharge and less than 5 polymorphonuclear leukocytes per high-power field. Urine was tested for Atopobium spp., BVAB-2, BVAB-3, Megasphaera spp., and Leptotrichia/Sneathia spp. using quantitative taxon-directed polymerase chain reaction.

RESULTS

Cases (n = 157) and controls (n = 102) were of similar age, education, and income, and most were white. Leptotrichia/Sneathia spp. was significantly associated with urethritis (24/157 [15.3%] vs. 6/102 [5.9%], P = 0.03). BVAB-2 was more common in cases than in controls (7/157 [4.5%] vs. 1/102 [1.0%], P = 0.15), and BVAB-3 (n = 2) and Megasphaera spp. (n = 1) were only detected in men with urethritis, but these bacteria were found only in men who also had Leptotrichia/Sneathia spp. Atopobium spp. was not associated with urethritis. The quantity of bacteria did not differ between cases and controls. Among treated cases, doxycycline was more effective than azithromycin for clinical cure of men with Leptotrichia/Sneathia spp. (9/10 vs. 7/12, P = 0.16) and BVAB-2 (3/3 vs. 0/3, P = 0.10).

CONCLUSIONS

Leptotrichia/Sneathia spp. may be urethral pathogens or contribute to a pathogenic microbiota that can also include BVAB-2, BVAB-3, and Megasphaera spp. Doxycycline may be more effective than azithromycin against these newly identified bacteria.

Microbiota and pelvic inflammatory disease

Female genital tract microbiota play a crucial role in maintaining health. Disequilibrium of the microbiota has been associated with increased risk of pelvic infections. In recent years, culture-independent molecular techniques have expanded understanding of the composition of genital microbiota and the dynamic nature of the microbiota. There is evidence that upper genital tract may not be sterile and may harbor microflora in the physiologic state. The isolation of bacterial vaginosis-associated organisms in women with genital infections establishes a link between pelvic infections and abnormal vaginal flora. With the understanding of the composition of the microbiota in healthy and diseased states, the next logical step is to identify the function of the newly identified microbes. This knowledge will further expand our understanding of the causation of pelvic infections, which may lead to more effective prevention and treatment strategies.

Stimulating an immune response? Oral sex is associated with less endometritis

Secondary analysis of the PID Evaluation and Clinical Health (PEACH) data suggests that among women presenting with signs and symptoms of pelvic inflammatory disease (PID), those who reported oral sex were less likely to have endometritis (adjusted odds ratio [OR] 0.5 [0.3-0.8]) than those who did not report oral sex. Adaptive immunity requires antigenic priming of the lymphatic system. As lymphatic tissue is abundant in the oropharynx, oral sex could lead to effective immune stimulation and prevent PID. To determine whether oral sex could be a protective factor for PID the relationship between self-reported oral sex and endometritis was analysed among 619 women with clinically suspected PID who participated in the PEACH study. Nearly one quarter of participants reported oral sex in the past four weeks. These women also reported a higher number of sexual partners, a new partner within the past four weeks and a higher frequency of sexual intercourse (all P < 0.03). They were more likely to smoke (P < 0.0001), drink alcohol (P < 0.004) and use recreational drugs (P < 0.02). Participants reporting oral sex were significantly less likely to be black or to have a positive test for Neisseria gonorrhoeae (7.8% versus 21.6%, P = 0.001). Women who disclosed oral sex were significantly less likely to have endometritis after adjusting for race, number of partners, recent new partner, smoking, alcohol use and drug use (adjusted OR 0.5 [0.3-0.8]). This is the first paper showing a negative association between oral sex and endometritis. This may be mediated by a protective immune response in the genital tract following priming in the oropharynx. This hypothesis needs to be tested in further studies.

Trospectomycin in acute pelvic inflammatory disease: a preliminary report

Objective: The purpose of this study was to compare the clinical efficacy and safety of intravenous trospectomycin to that of cefoxitin plus doxycycline in the treatment of women hospitalized with acute pelvic inflammatory disease (PID).

Methods: Thirty-nine patients admitted with a clinical diagnosis of an acute PID were enrolled in this prospective, single-blind study. Patients were treated with either intravenous trospectomycin, 500 mg every 8 h, or intravenous cefoxitin, 2 g every 6 h, plus oral or intravenous doxycycline, 100 mg every 12 h, in a 2:1 ratio. The patients were followed for clinical response and side effects. Both groups of patients were discharged on oral doxycycline for 10 days. Appropriate cultures were obtained before starting inpatient treatment, on completion of inpatient treatment, and at 2 follow-up visits.

Results: The overall success rate for trospectomycin was 95.6% and for cefoxitin/doxycycline was 91.6%. This difference was not statistically significant (P = 0.63). Trospectomycin was found to be effective against Chlamydia trachomatis.

Conclusions: Single-agent therapy with trospectomycin may be as effective as cefoxitin plus doxycycline in the treatment of women hospitalized with acute PID.

Pelvic Inflammatory Disease: Current Concepts of Diagnosis and Management

Pelvic inflammatory disease (PID), one of the most common infections in non-pregnant women of reproductive age, remains an important public health problem. It is associated with major long-term sequelae, including tubal factor infertility, ectopic pregnancy, and chronic pelvic pain. In addition, treatment of acute PID and its complications incurs substantial health care costs. Prevention of these long-term sequelae is dependent upon clinicians having a high index of suspicion in order to make an early diagnosis and development of treatment strategies based on knowledge of the microbiologic etiology of acute PID. It is well accepted that acute PID is a polymicrobic infection. The sexually transmitted organisms, Neisseria gonorrhoeae and Chlamydia trachomatis, are present in many cases and microorganisms comprising the endogenous vaginal and cervical flora are frequently associated with PID. This includes anaerobic and facultative bacteria, similar to those associated with bacterial vaginosis. Genital tract mycoplasmas, most importantly Mycoplasma genitalium, have recently also been implicated as a cause of acute PID. As a consequence, treatment regimens for acute PID should provide broad spectrum coverage that is effective against these microorganisms.

Treatment of acute pelvic inflammatory disease

Pelvic inflammatory disease (PID), one of the most common infections in nonpregnant women of reproductive age, remains an important public health problem. It is associated with major long-term sequelae, including tubal factor infertility, ectopic pregnancy, and chronic pelvic pain. In addition, treatment of acute PID and its complications incurs substantial health care costs. Prevention of these long-term sequelae is dependent upon development of treatment strategies based on knowledge of the microbiologic etiology of acute PID. It is well accepted that acute PID is a polymicrobic infection. The sexually transmitted organisms, Neisseria gonorrhoeae and Chlamydia trachomatis, are present in many cases, and microorganisms comprising the endogenous vaginal and cervical flora are frequently associated with PID. This includes anaerobic and facultative bacteria, similar to those associated with bacterial vaginosis. Genital tract mycoplasmas, most importantly Mycoplasma genitalium, have recently also been implicated as a cause of acute PID. As a consequence, treatment regimens for acute PID should provide broad spectrum coverage that is effective against these microorganisms.

Diagnostic evaluation of pelvic inflammatory disease

Pelvic inflammatory disease (PID) is a serious public health and reproductive health problem in the United States. An early and accurate diagnosis of PID is extremely important for the effective management of the acute illness and for the prevention of long-term sequelae. The diagnosis of PID is difficult, with considerable numbers of false-positive and false-negative diagnoses. An abnormal vaginal discharge or evidence of lower genital tract infection is an important and predictive finding that is often underemphasized and overlooked. This paper reviews the clinical diagnosis and supportive laboratory tests for the diagnosis of PID and outlines an appropriate diagnostic plan for the clinician and the researcher.

Rab6 and Rab11 regulate Chlamydia trachomatis development and golgin-84-dependent Golgi fragmentation

Many intracellular pathogens that replicate in special membrane bound compartments exploit cellular trafficking pathways by targeting small GTPases, including Rab proteins. Members of the Chlamydiaceae recruit a subset of Rab proteins to their inclusions, but the significance of these interactions is uncertain. Using RNA interference, we identified Rab6 and Rab11 as important regulators of Chlamydia infections. Depletion of either Rab6 or Rab11, but not the other Rab proteins tested, decreased the formation of infectious particles. We further examined the interplay between these Rab proteins and the Golgi matrix components golgin-84 and p115 with regard to Chlamydia-induced Golgi fragmentation. Silencing of the Rab proteins blocked Chlamydia-induced and golgin-84 knockdown-stimulated Golgi disruption, whereas Golgi fragmentation was unaffected in p115 depleted cells. Interestingly, p115-induced Golgi fragmentation could rescue Chlamydia propagation in Rab6 and Rab11 knockdown cells. Furthermore, transport of nutrients to Chlamydia, as monitored by BODIPY-Ceramide, was inhibited by Rab6 and Rab11 knockdown. Taken together, our results demonstrate that Rab6 and Rab11 are key regulators of Golgi stability and further support the notion that Chlamydia subverts Golgi structure to enhance its intracellular development.

Treatment strategies for pelvic inflammatory disease

BACKGROUND

Pelvic inflammatory disease (PID) is one of the most common infections seen in nonpregnant reproductive-age women. It is a major public health problem associated with substantial medical complications (e.g., infertility, ectopic pregnancy, and chronic pelvic pain) and healthcare costs. Prevention of these long-term sequelae requires treatment strategies that are based on the microbiologic etiology of acute PID.

OBJECTIVE

To determine appropriate antimicrobial regimens for the treatment of acute PID based on published literature.

METHODS

Clinical trials published since 2002 were assessed conducting a systematic search of the literature on the treatment of acute PID using PubMed (National Library of Congress). The search was limited to articles written in English and published from 1 January 2002 to 30 June 2008.

RESULTS

Acute PID is a polymicrobic infection caused by both sexually transmitted organisms (primarily Neisseria gonorrhoeae and Chlamydia trachomatis) and microorganisms found in the endogenous flora of the vagina and cervix. The latter include anaerobic bacteria and facultative bacteria, many of which are associated with bacterial vaginosis. Genital tract mycoplasmas, most importantly Mycoplasma genitalium, may also be implicated in the etiology of acute PID. Because of this polymicrobial nature, currently available evidence, as well as recommendations by the CDC, support the use of broad-spectrum regimens (oral or parenteral) that provide adequate coverage against these microorganisms.

A randomized double-blind comparison of moxifloxacin and doxycycline/metronidazole/ciprofloxacin in the treatment of acute, uncomplicated pelvic inflammatory disease

This multicentre, double-blind study was undertaken to demonstrate non-inferiority of once-daily oral moxifloxacin compared with combination therapy in the management of acute, uncomplicated pelvic inflammatory disease (PID). Women aged ≥18 years with PID were randomized to receive moxifloxacin (400 mg once daily) for 14 days or comparator treatment (doxycycline [100 mg twice daily] plus metronidazole [400 mg three times daily] for 14 days, plus one single 500-mg ciprofloxacin dose). Of the 434 valid per protocol (PP) patients, the overall clinical success rates at 2–14 days post-therapy were 96.6% (moxifloxacin) and 98.0% (comparator); moxifloxacin was non-inferior to the comparator regimen both in the PP (95% confidence interval [CI]: −4.5, 1.6) and intent-to-treat (95% CI: −5.8, 6.9) populations. Clinical success rates at 21–35 days post-therapy were 93.8% (166/177; data missing for 47 patients) for moxifloxacin and 91.3% (147/161; data missing for 37 patients) for the comparator. Bacteriological success rates at 2–14 days post-therapy were 92.5% (moxifloxacin) and 88.2% (comparator). Once-daily dosing and proven efficacy suggest that moxifloxacin may be of value in acute, uncomplicated PID.

Prevalence of sexually transmitted diseases among pregnant women in Ilorin, Nigeria

In a cross-sectional study, 230 pregnant women attending the antenatal clinic of the University of Ilorin Teaching Hospital (UITH), Ilorin, Nigeria from January 2000 to December 2000 were screened randomly to determine the prevalence of common STDs among them, using conventional methods. One hundred and fourteen (49.4%) of the subjects harboured various agents including Candida spp. (37.8%), Trichomonas vaginalis (4.7%), Gardnerella vaginalis (3.9%), syphilis (1.7%) and Neisseria gonorrhea (1.3%). Risk factors associated with significant infection were young age and level of education. The importance of routine STD screening in pregnancy especially among the young and illiterate is advocated. It is recommended that routine screening for STDs should be incorporated into antenatal care.

Bacterial vaginosis in female facility workers in north-western Tanzania: prevalence and risk factors

OBJECTIVES

To determine prevalence of, and risk factors for, bacterial vaginosis (BV) among herpes simplex virus (HSV) 2 seropositive Tanzanian women at enrollment into a randomised, placebo-controlled trial of HSV suppressive treatment.

METHODS

1305 HSV-2 seropositive women aged 16-35 years working in bars, guesthouses and similar facilities were interviewed, examined and tested for HIV, syphilis, Neisseria gonorrhoeae, Chlamydia trachomatis, BV, candidiasis and trichomoniasis. Factors associated with BV were analysed using logistic regression to estimate odds ratios and 95% confidence intervals.

RESULTS

BV prevalence was 62.9%; prevalence of Nugent score 9-10 was 16.1%. Independent risk factors for BV were work facility type, fewer dependents, increasing alcohol consumption, sex in the last week (adjusted OR 2.03; 95% CI 1.57 to 2.62), using cloths or cotton wool for menstrual hygiene, HIV (adjusted OR 1.41; 95% CI 1.09 to 1.83) and Trichomonas vaginalis infection. There was no association between BV and the frequency or method of vaginal cleansing. However, BV was less prevalent among women who reported inserting substances to dry the vagina for sex (adjusted OR 0.44; 95% CI 0.25 to 0.75).

CONCLUSION

BV was extremely prevalent among our study population of HSV-2 positive female facility workers in North-western Tanzania. Although recent sex was associated with increased BV prevalence, vaginal drying was associated with lower BV prevalence. Further studies of the effects of specific practices on vaginal flora are warranted.

[Bacterial vaginosis]

Bacterial vaginosis is a widely spread health problem with multiple connotations. It has been the subject of many studies and work during decades and it still remains a polemic entity, with contradictory finding. The polymicrobian etiology, unsolved epidemiology, obstetrico-gynecological complications and high recurrence rate following treatment, make this infection a target for researchers. It is not an inflammatory process -yet an immune response exists. In this disorder, vaginal discharge increases, and it is associated with a high risk of developing sexually transmitted diseases.

Can bacterial vaginosis help to find sexually transmitted diseases, especially chlamydial cervicitis?

This study was undertaken to establish reliable factors in order to identify chlamydial cervicitis among suspicious patients. Between January and December 2007, 406 patients who were suspected to have cervicitis due to clinical symptoms, were tested with polymerase chain reaction (PCR) for Chlamydia trachomatis (CT), vaginal pH and Nugent score (NS) in our University hospital and related clinics. During the same period, 67 patients who were diagnosed as having other sexually transmitted diseases (Neisseria gonorrhoeae (NG), Trichomonas vaginalis, Condyloma acuminatum and genital herpes) were also made to participate in this study. Eighty-nine women (22%) were positive for CT PCR. Bacterial vaginosis (BV)-positive women were tested positive for CT PCR (75/288), significantly higher than those without BV (6/66, P = 0.01). In addition, under 20-years old women were positive for CT PCR (24/57), significantly higher than those who were over 30 years old (16/113, P = 0.001). The proportion of patients with high NS (>7) in CT, NG and T. vaginalis cases were 75/89 (84.3%), 22/27 (81.5%) and 11/14 (78.6%), respectively. Whereas the high NS of the C. acuminatum and genital herpes groups were recorded at 7/14 (50%) and 4/12 (33.3%), respectively. Younger women with BV could be at a higher risk for STDs, especially for CT cervicitis.

Diagnosis and treatment of pelvic inflammatory disease

Pelvic inflammatory disease (PID), the infection and inflammation of the female upper genital tract, is a common cause of infertility, chronic pain and ectopic pregnancy. Diagnosis and management are challenging, largely resulting from varying signs and symptoms and a polymicrobial etiology that is not fully delineated. Owing to the potential for serious sequelae, a low threshold for diagnosis and treatment is recommended. As PID has a multimicrobial etiology, including Neisseria gonorrhoeae, Chlamydial trachomatis and anaerobic and mycoplasmal bacteria, treatment of PID should consist of a broad spectrum antibiotic regimen. Recent treatment trials have focused on shorter duration regimens, such as azithromycin, and monotherapies including ofloxacin, but data are sparse. Research comparing sequelae development by differing antimicrobial regimens is extremely limited, but will ultimately shape future treatment guidelines.

A delicate balance: risk factors for acquisition of bacterial vaginosis include sexual activity, absence of hydrogen peroxide-producing lactobacilli, black race, and positive herpes simplex virus type 2 serology

BACKGROUND

The etiology of bacterial vaginosis (BV) is poorly understood, but better definition of the risk factors associated with its acquisition should improve our understanding of this complex disease entity.

METHODS

A longitudinal cohort study of young sexually active women was conducted to identify variables associated with BV acquisition. Seven hundred seventy-three women without BV at enrollment were followed at 4-month intervals for 1 year. At each visit, demographic and behavioral interview data, a vaginal smear for the Gram stain diagnosis of BV, and a serum sample for detection of herpes simplex virus type 1 (HSV-1) and HSV-2 type-specific antibodies were collected.

RESULTS

The overall incidence of BV acquisition was 36 cases/100 woman-years (223 acquisitions of BV during 619 woman-years of follow-up). Acquisition of BV was independently associated with black race, cigarette smoking, vaginal intercourse, receptive anal sex before vaginal intercourse, sex with an uncircumcised male partner, lack of vaginal H2O2-producing lactobacilli, and the detection of HSV-2 serum antibodies at the visit before BV acquisition. Longitudinal analyses revealed that HSV-2 serum antibodies were independently associated with loss of H2O2-producing lactobacilli.

CONCLUSIONS

Our findings suggest that multiple and diverse risk factors can contribute to BV acquisition. They also illustrate why a more complete understanding of BV pathogenesis and the formulation of effective BV prevention strategies have been elusive. Further work will be needed to determine the specific effects of HSV-2 infection on vaginal flora composition and the acquisition of BV.

Mycoplasma genitalium among women with nongonococcal, nonchlamydial pelvic inflammatory disease

Pelvic inflammatory disease (PID) is a frequent condition of young women, often resulting in reproductive morbidity. Although Neisseria gonorrhoeae and/or Chlamydia trachomatis are/is recovered from approximately a third to a half of women with PID, the etiologic agent is often unidentified. We need PCR to test for M genitalium among a pilot sample of 50 women with nongonococcal, nonchlamydial endometritis enrolled in the PID evaluation and clinical health (PEACH) study. All participants had pelvic pain, pelvic organ tenderness, and leukorrhea, mucopurulent cervicitis, or untreated cervicitis. Endometritis was defined as ≥5 surface epithelium neutrophils per ×400 field absent of menstrual endometrium and/or ≥2 stromal plasma cells per ×120 field. We detected M genitalium in 7 (14%) of the women tested: 6 (12%) in cervical specimens and 4 (8%) in endometrial specimens. We conclude that M genitalium is prevalent in the endometrium of women with nongonococcal, nonchlamydial PID.

Antibiotic therapy for acute pelvic inflammatory disease: the 2006 Centers for Disease Control and Prevention sexually transmitted diseases treatment guidelines

Pelvic inflammatory disease (PID) is a substantial cause of reproductive morbidity in young women. A systematic review of the literature related to PID management was performed in preparation for the 2006 Centers for Disease Control and Prevention sexually transmitted diseases treatment guidelines. This search was conducted using PubMed and was limited to articles written in English and published between 1 January 2002 and 31 January 2005 that were related to PID treatment. Studies were evaluated for new data on PID with regard to site, route, and timing of antimicrobial administration; regimen adherence; experience in adolescents and women >35 years of age; coinfection with human immunodeficiency virus; and management of sex partners. Strong evidence suggests that neither site nor route of treatment administration affects the short- or long-term major outcome of women with mild or moderate clinical presentations. Data on these outcomes in women with more severe clinical presentations are inadequate to provide guidance as to the preferred agents or route of administration. Important contributions to the literature that impact the 2006 guidelines are described in this article.

Chlamydial interferon gamma immune evasion influences infection tropism

Chlamydia trachomatis is a human pathogen and Chlamydia muridarum is a mouse pathogen but paradoxically, they share near genomic synteny. The majority of strain-variable genes are located primarily in a hyper-variable region termed the plasticity zone. Tryptophan synthase and cytotoxin are plasticity zone genes unique to the human and murine strains, respectively. Tryptophan synthase is a virulence factor that differentiates C. trachomatis strains into genital and ocular disease pathotypes, whereas cytotoxin(s) is a virulence factor linked to murine infection tropism. Divergence in these loci is strongly correlated with host-specific interferon gamma effector activities, suggesting that these virulence genes have co-evolved with their respective hosts as a primary mechanism to evade innate immunity. These findings have important implications for chlamydial animal modeling studies.

Epidemiology, pathogenesis and treatment of pelvic inflammatory disease

Pelvic inflammatory disease, the infection and inflammation of the female upper genital tract, is a common cause of infertility, chronic pain and ectopic pregnancy. Diagnosis and management are challenging, due largely to a polymicrobial etiology which is not fully delineated. Signs and symptoms of this syndrome vary widely, further complicating diagnosis and treatment. Due to the potential for serious sequelae, a low threshold for diagnosis and treatment is recommended. Since pelvic inflammatory disease has a multimicrobial etiology including Neisseria gonorrhoeae, Chlamydia trachomatis and anaerobic and mycoplasmal bacteria, treatment of pelvic inflammatory disease should be broad spectrum. Recent treatment trials have focused on shorter duration regimens such as azithromycin and monotherapies including ofloxacin, although data are sparse. Research comparing sequelae development by differing antimicrobial regimens is extremely limited, but will ultimately shape future treatment guidelines. Several promising short-duration and monotherapy antibiotic regimens should be evaluated in pelvic inflammatory disease treatment trials for compliance, microbiological and clinical cure, and reduction of subsequent adverse reproductive and gynecological morbidity.

A cluster analysis of bacterial vaginosis-associated microflora and pelvic inflammatory disease

Controversy surrounds the association between bacterial vaginosis (BV) and pelvic inflammatory disease (PID). Women (N = 1,140) were ascertained at five US centers, enrolled (1999-2001), and followed up for a median of 3 years. Serial vaginal swabs were obtained for Gram's stain and cultures. PID was defined as 1) histologic endometritis or 2) pelvic pain and tenderness plus oral temperature >38.8 degrees C, leukorrhea or mucopus, erythrocyte sedimentation rate >15 mm/hour, white blood cell count >10,000, or gonococcal/chlamydial lower genital infection. Exploratory factor analysis identified two discrete clusters of genital microorganisms. The first correlated with BV by Gram's stain and consisted of the absence of hydrogen peroxide-producing lactobacillus, Gardnerella vaginalis, Mycoplasma hominis, anaerobic gram-negative rods, and, to a lesser degree, Ureaplasma urealyticum. The second, unrelated to BV by Gram's stain, consisted of Enterococcus species and Escherichia coli. Being in the highest tertile in terms of growth of BV-associated microorganisms increased PID risk (adjusted rate ratio = 2.03, 95% confidence interval: 1.16, 3.53). Carriage of non-BV-associated microorganisms did not increase PID risk. Women with heavy growth of BV-associated microorganisms and a new sexual partner appeared to be at particularly high risk (adjusted rate ratio = 8.77, 95% confidence interval: 1.11, 69.2). When identified by microbial culture, a combination of BV-related microorganisms significantly elevated the risk of acquiring PID.

What's new in bacterial vaginosis and trichomoniasis?

The use of biochemical profiles and new molecular microbiologic methodologies is transforming our understanding of BV. Most important is the recognition of different subgroups of women who have BV who are at variable risk of certain obstetric and gynecologic complications. New diagnostic tests may soon be available that will allow women to test self-obtained specimens. Treatment of BV has lagged, although innovative methods appear to be helpful in managing recurrent diseases.

Bacterial vaginosis (BV) and the risk of incident gonococcal or chlamydial genital infection in a predominantly black population

OBJECTIVE

The objective of this study was to assess in prospective data whether bacterial vaginosis (BV) is associated with gonococcal/chlamydial cervicitis.

STUDY

A total of 1179 women at high risk for sexually transmitted infections was followed for a median of 3 years. Every 6 to 12 months, vaginal swabs were obtained for Gram stain, culture of microflora, and Neisseria gonorrhoeae and Chlamydia trachomatis. A Gram stain score of 7 to 10 based on the Nugent criteria categorized BV.

RESULTS

Baseline BV was associated with concurrent gonococcal/chlamydial infection (adjusted odds ratio, 2.83; 95% confidence interval [CI], 1.81-4.42). However, the association between BV and subsequent, incident gonococcal/chlamydial genital infection was not significant (adjusted relative risk [RR], 1.52; 95% CI, 0.74-3.13). Dense growth of pigmented, anaerobic Gram-negative rods (adjusted RR, 1.93; 95% CI, 0.97-3.83) appeared to elevate the risk for newly acquired gonococcal/chlamydial genital infection.

CONCLUSIONS

BV was common among a predominantly black group of women with concurrent gonococcal/chlamydial infection but did not elevate the risk for incident infection.

Pelvic Inflammatory Disease in Adolescents

Pelvic inflammatory disease (PID) is a polymicrobial infection typically occurring in sexually active females. It occurs when microorganisms ascend from the lower genital tract into the upper genital tract. The clinical presentation varies in severity, with most patients presenting with mild disease. Complications include tubo-ovarian abscess, ectopic pregnancy, infertility, and chronic pain. The newly revised criteria issued by the Centers for Disease Control and Prevention now include either cervical motion tenderness or adnexal tenderness with unchanged additional criteria.

Bacterial vaginosis. Transmission, role in genital tract infection and pregnancy outcome: an enigma

Whether bacterial vaginosis (BV) is acquired from an endogenous or an exogenous source is subject to controversy. Despite findings of an association between sexual behaviour and BV, some data indicate that BV is not a sexually transmitted infection in the traditional sense, while other data indicate that BV is an exogenous infection. A third aspect of BV is its tendency to go unnoticed by affected women. All of this will have a strong impact on how physicians view the risks of asymptomatic BV. This review focuses on whether or not BV should be regarded as a sexually transmitted infection (STI), its role in postoperative infections and pelvic inflammatory disease (PID), and on whether or not treatment of BV during pregnancy to reduce preterm delivery should be recommended. The reviewed studies do not lend unequivocal support to an endogenous or exogenous transmission of the bacteria present in BV. For women undergoing gynaecological surgery such as therapeutic abortion, the relative risk of postoperative infection is clearly elevated (approx. 2.3-2.8). A weaker association exists between BV and pelvic inflammatory disease. Data on treatment of BV as a way of reducing preterm delivery are inconclusive and do not support recommendations for general treatment of BV during pregnancy. The discrepant associations between BV and preterm birth found in recent studies may be explained by variations in immunological response to BV. Genetic polymorphism in the cytokine response--both regarding the TNF alleles and in interleukin production--could make women more or less susceptible to BV, causing different risks of preterm birth. Thus, studies on the vaginal inflammatory response to microbial colonization should be given priority.

[Chlamydia trachomatis urogenital infections in women. Best diagnostic approaches]

Chlamydiae are obligate intracellular bacteria. Chlamydia trachomatis is the most common sexually transmitted disease (STD). The C. trachomatis damaging disease sequelae such as sterility is based on intense and chronic inflammation elicited and maintained by reinfection or persistent infection. The high prevalence of C. trachomatis infection reflects the long and successful adaptation of these organisms to persist in their human host population. The large group of asymptomatically infected persons is not only at risk of serious long-term sequelae but also sustains transmission within communities. C. trachomatis acute infections have been diagnosed by cell culture, direct immunofluorescence, enzyme immunoassay, direct DNA hybridization, and more recently by nucleic acid amplification tests (NAATs). In chronic or persistent chlamydial infections, the level of Chlamydia is very low and bacteria are often not viable. Such infections would be characterized by continuing positive NAATs but only intermittent isolation of viable Chlamydia and positive assays for chlamydial protein antigen. The development of NAATs has been a major advance in the field of chlamydial diagnosis. The use of NAATs associated with serology test is the best diagnosis. The introduction of assays based on amplification of genetic material has subsequently increased the sensitivity of detecting chlamydial infections and offers the opportunity to use non-invasive sampling techniques to screen for infections in asymptomatic subjects. In this article, it was proposed the best diagnosis approaches for detection of acute and chronic infections.

Vaginal flora morphotypic profiles and assessment of bacterial vaginosis in women at risk for HIV infection

Specific morphotypic profiles of normal and abnormal vaginal flora, including bacterial vaginosis (BV), were characterized. A prospective study of 350 women yielded concurrent Gram-stain data and clinical assessment (n = 3455 visits). Microbiological profiles were constructed by Gram stain. Eight profile definitions were based on dichotomizing the levels of Lactobacillus, Gardnerella, and curved, Gram-negative bacillus (Mobiluncus) morphotypes. Of these, two were rare, and the other six demonstrated a graded association with the clinical components of BV. The proposed profiles from the Gram stain reflect the morphotypic categories describing vaginal flora that may enable clearer elucidation of gynecologic and obstetric outcomes in various populations.

Genital tract shedding of herpes simplex virus type 2 in women: effects of hormonal contraception, bacterial vaginosis, and vaginal group B Streptococcus colonization

BACKGROUND

Genital infections due to herpes simplex virus type 2 (HSV-2) are characterized by frequent reactivation and shedding of the virus and by the attendant risk of transmission to sexual partners. We investigated the effects of vaginal coinfections and hormonal contraceptive use on genital tract shedding of HSV-2 in women.

METHODS

A total of 330 HSV-2-seropositive women were followed every 4 months for a year. At each visit, one vaginal swab specimen was obtained for detection of HSV-2 by polymerase chain reaction, a second vaginal swab specimen was obtained for detection of group B Streptococcus (GBS) organisms and yeast by culture, and a vaginal smear was obtained for the diagnosis of bacterial vaginosis by Gram staining.

RESULTS

HSV-2 DNA was detected in 88 (9%) of 956 vaginal swab specimens. Independent predictors of genital tract shedding of HSV-2 were HSV-2 seroconversion during the previous 4 months (adjusted odds ratio [aOR], 3.0; 95% confidence interval [CI], 1.3-6.8), bacterial vaginosis (aOR, 2.3; 95% CI, 1.3-4.0), high-density vaginal GBS colonization (aOR, 2.2; 95% CI, 1.3-3.8), and use of hormonal contraceptives (aOR, 1.8; 95% CI, 1.1-2.8).

CONCLUSIONS

The present study identifies hormonal contraceptive use, bacterial vaginosis, and high-density vaginal GBS colonization as risk factors for genital tract shedding of HSV-2 in women. Because hormonal contraceptives are used by millions of women worldwide and because bacterial vaginosis and vaginal GBS colonization are common vaginal conditions, even modest associations with HSV-2 shedding would result in substantial attributable risks for transmission of the virus.

Bacterial Vaginosis and Anaerobic Bacteria Are Associated with Endometritis

BACKGROUND

Chlamydia trachomatis and/or Neisseria gonorrhoeae account for approximately one-third to one-half of pelvic inflammatory disease (PID) cases. Thus, up to 70% of cases have an unknown, nongonococcal/nonchlamydial microbial etiology.

METHODS

We investigated the associations of N. gonorrhoeae, C. trachomatis, bacterial vaginosis, anaerobic bacteria, facultative bacteria, and lactobacilli with endometritis among 278 women with complete endometrial histology and culture from the PID Evaluation and Clinical Health Study.

RESULTS

Women with acute endometritis were less likely to have H(2)O(2)-producing Lactobacillus species (odds ratio [OR], 0.1; 95% confidence interval [CI], 0.01-0.8) and more likely to be infected with C. trachomatis (OR, 16.2; 95% CI, 4.6-56.6), N. gonorrhoeae (OR, 11.6; 95% CI, 4.5-29.9), diphtheroids (OR, 5.0; 95% CI, 2.1-12.2), black-pigmented gram-negative rods (OR, 3.1; 95% CI, 1.4-7.0), and anaerobic gram-positive cocci (OR, 2.1; 95% CI, 1.0-4.3) and to have bacterial vaginosis (OR, 2.4; 95% CI, 1.3-4.3).

CONCLUSIONS

We conclude that bacterial vaginosis-associated organisms are frequent among women with PID. Because these organisms were strongly associated with endometritis, we recommend that all women with PID be treated with regimens that include metronidazole.

Bacterial Vaginosis and Risk of Pelvic Inflammatory Disease

BACKGROUND

Bacterial vaginosis commonly is found in women with pelvic inflammatory disease (PID), but it is unclear whether bacterial vaginosis leads to incident PID.

METHODS

Women (n = 1,179) from 5 U.S. centers were evaluated for a median of 3 years. Every 6-12 months, vaginal swabs were obtained for gram stain and culture of microflora. A vaginal microflora gram stain score of 7-10 was categorized as bacterial vaginosis. Pelvic inflammatory disease was diagnosed by presence of either histologic endometritis or pelvic pain and tenderness plus one of the following: oral temperature greater than 38.3 degrees C; sedimentation rate greater than 15 mm/hour; white blood count greater than 10,000; or lower genital tract detection of leukorrhea, mucopus, or Neisseria gonorrhoeae or Chlamydia trachomatis.

RESULTS

After adjustment for relevant demographic and lifestyle factors, baseline bacterial vaginosis was not associated with the development of PID (adjusted hazard ratio 0.89, 95% confidence interval 0.55-1.45). Carriage of bacterial vaginosis in the previous 6 months before a diagnosis (adjusted risk ratio 1.31, 95% confidence interval 0.71-2.42) also was not significantly associated with PID. Similarly, neither absence of hydrogen peroxide-producing Lactobacillus nor high levels of Gardnerella vaginalis significantly increased the risk of PID. Dense growth of pigmented, anaerobic gram-negative rods in the 6 months before diagnosis did significantly increase a woman's risk of PID (P =.04). One subgroup of women, women with 2 or more recent sexual partners, demonstrated associations among bacterial vaginosis, Gardnerella vaginalis, anaerobic gram-negative rods, and PID.

CONCLUSION

In this cohort of high-risk women, after adjustment for confounding factors, we found no overall increased risk of developing incident PID among women with bacterial vaginosis.

LEVEL OF EVIDENCE

II-2

Acceptability of a self-sampling technique to collect vaginal smears for gram stain diagnosis of bacterial vaginosis

To diagnose asymptomatic bacterial vaginosis (BV), self-sampled vaginal smears were collected during a study of risk factors for preterm birth in African American women. More than 90% of those women who were willing to participate in the interview portion of the study were also willing to provide a self-sampled vaginal smear. The smears are an acceptable and efficient way of detecting BV in an urban minority population.

Gynecologic consequences of bacterial vaginosis

BV is a prevalent sexually associated infection linked to several gynecologic complications and acquisition of STDs and acquisition and transmission of HIV. It seems that normalization of the vaginal flora may be effective for preventing short-term complications. The implications of screening and treating BV to prevent long-term complications are less clear and may depend on the availability of more effective treatment regimens.

Pelvic inflammatory disease: new diagnostic criteria and treatment

PID is a common infection in reproductive-age women that presents an enormous public health and economic burden. It is responsible for much short- and long-term morbidity that may necessitate interventions subsequent to the original infection. Mild PID seems to be much more common than severe or "classic" PID, and the importance of early recognition and treatment cannot be understated. Current treatment regimens seem to be effective in terms of immediate clinical efficacy. As we learn more about the frequency and importance of subclinical PID, the true burden of upper genital tract infection upon reproductive age women continues to be elucidated.

Follow-up of users of intrauterine device with and without bacterial vaginosis and other cervicovaginal infections

This study aimed to assess the prevalence of bacterial vaginosis (BV) and other cervicovaginal infections, as well as the incidence of complications among new users of IUD, 1 and 6 months after its insertion, in the City of Campinas, Brazil. A total of 223 women who had a TCu-380A IUD inserted from May through November 2001, were included in the study. After the IUD insertion all women were scheduled to two additional visits: after 1 month and after 6 months, when they were interviewed and a pelvic examination was performed, along with a collection of specimens from the vagina and the endocervix for laboratory testing. The Nugent's criterion was used for the BV diagnosis. They were also evaluated with regard to presence of complications possibly related to IUD insertion and use, i.e., abnormal bleeding, dysmenorrhea, expulsion and pelvic inflammatory disease. The prevalence of cervicovaginal infections was 29.1%, BV being the most frequent (19.7%). Dysmenorrhea was more frequent among women with BV than among women without BV (p = 0.03). A trend of abnormal bleeding being more frequent among women with BV was also found. In conclusion, BV after 1 month of IUD insertion was not associated with IUD complications, with the exception of dysmenorrhea.

Polymorphisms in Chlamydia trachomatis tryptophan synthase genes differentiate between genital and ocular isolates

We previously reported that laboratory reference strains of Chlamydia trachomatis differing in infection organotropism correlated with inactivating mutations in the pathogen's tryptophan synthase (trpBA) genes. Here, we have applied functional genomics to extend this work and find that the paradigm established for reference serovars also applies to clinical isolates - specifically, all ocular trachoma isolates tested have inactivating mutations in the synthase, whereas all genital isolates encode a functional enzyme. Moreover, functional enzyme activity was directly correlated to IFN-gamma resistance through an indole rescue mechanism. Hence, a strong selective pressure exists for genital strains to maintain a functional synthase capable of using indole for tryptophan biosynthesis. The fact that ocular serovars (serovar B) isolated from the genital tract were found to possess a functional synthase provided further persuasive evidence of this association. These results argue that there is an important host-parasite relationship between chlamydial genital strains and the human host that determines organotropism of infection and the pathophysiology of disease. We speculate that this relationship involves the production of indole by components of the vaginal microbial flora, allowing chlamydiae to escape IFN-gamma-mediated eradication and thus establish persistent infection.