Accuracy of clinical diagnosis of genital ulcer disease

Rollet's mixed chancre in Brazilian pregnant women: An unusual case report

Syphilis is a sexually transmitted infection (STI) caused by the bacterium Treponema pallidum and has shown a significant increase in recent decades. It may be associated with other STIs such as soft chancre or chancroid, which is an uncommon infection in Brazil. The presence of ulcerated genital lesions is associated with a higher risk of HIV transmission. An accurate clinical and laboratory diagnosis of genital ulcer disease is essential for the appropriate treatment of pregnant women, in order to avoid congenital syphilis, a severe complication of mother-to-child vertical transmission. We report the case of a woman in the third trimester of pregnancy with Rollet's mixed chancre and describe the clinical and laboratory diagnosis, as well as the treatment of these diseases in pregnancy. We emphasize the importance of training health professionals on early diagnosis and treatment in order to avoid mother-to-child transmission.

Management and Control of Sexually- transmitted Infections and their Implications for AIDS Control in South-East Asia

Sexually-transmitted infections (STIs) are highly prevalent in developing countries, including many parts of South-East Asia. The burden of diseuse due to these infections and their complications is enormous, particularly among women. STIs thus present a major public health problem in their own right. Accessible, affordable and effective treatment services need to be made available everywhere. The syndromic approach to STI diagnosis and case management based upon locally adapted standard treatment algorithm is byfarsuperiorto the presumptive clinical diagnostic approach that is still used in many parts of the region. This approach is particularly suitable in areas where efficient and affordable laboratory services are not available. STIs are known to enhance HIV transmission. Effective control of curable STIs has been shown to significantly reduce HIV incidence in popula tions. Such control measures should address all major steps of the Piot model: they should include primary prevention, screening to detect asymptomatic or neglected STI particularly among high- risk behaviour groups, and effertive treatment services for those who seek care forsymptomatic STI. So far the public health response to STI in South and South-East Asia has been varied. Some countries have addressed the problem quite vigorously, but most need to mount a much stronger coordinated response in the face of the accelerating HIV epidemic in the region. There is also a substantial need to systematically monitor and evaluate ongoing activities, including the quality of STI case management, and to make an attempt towards bridging the wide rift between policy and actual practices.

Correlates of Bacterial Ulcers and Acute HSV-2 Infection among Men with Genital Ulcer Disease in South Africa: Age, Recent Sexual Behaviors, and HIV

Data from baseline surveys and STI/HIV laboratory tests (n=615 men) were used to examine correlates of bacterial ulcers (Treponema pallidum, Haemophilus ducreyi, or Chlamydia trachomatis L1-L3 detected in ulcer) and acute HSV-2 ulcers (HSV-2 positive ulcer specimen, HSV-2 sero-negative, and negative for bacterial pathogens) vs. recurrent HSV-2 ulcers (sero-positive), separately. Compared to men with recurrent HSV-2 ulcers, men with bacterial ulcers had larger ulcers but were less likely to be HIV-positive whereas men with acute HSV-2 ulcers were younger with fewer partners. Acute HIV was higher among men with bacterial and acute HSV-2 ulcers; the difference was not statistically significant.

HIV and Men

INTRODUCTION

Since the initial description of HIV and AIDS, monumental efforts have been made both in the developed and developing countries to devise strategies and medications to control the disease. The advent of highly active antiretroviral therapy has now meant that the diagnosis of HIV is no longer a life-sentence and compliant patients with HIV can expect life expectancy similar to their noninfected peers. Consequently new challenges have arisen in the management of benign conditions.

AIM

To provide an overview of the key conditions and issues that HIV/AIDS patients may present with to an andrological service.

METHODS

Using PubMed, we screened the literature for studies on common andrological conditions specifically pertaining to HIV and AIDS.

MAIN OUTCOME MEASURES

The urological manifestations of HIV/AIDS in men have been summarized in an attempt to provide a useful guide for sexual health practitioners dealing with HIV-positive men.

RESULTS

As a result of advancements in pharmaceuticals, life expectancy of men infected with HIV has improved almost to that of the general population in developed countries. Therefore, clinicians are faced with non-life-threatening urological problems that affect the quality of life of men with HIV. The majority of these problems can be managed easily, by adapting a "patient-centered" approach, instead of "disease-centered" algorithms.

CONCLUSION

With improved survival and understanding, patients with HIV/AIDS can and do expect to enjoy a healthy sex life. With appropriate counseling around safe sex and careful management with consideration for disease-specific issues as well as the influence of medical therapy, patients can achieve a good quality of life.

Evaluating HIV Prevention Programs: Herpes Simplex Virus Type 2 Antibodies as Biomarker for Sexual Risk Behavior in Young Adults in Resource-Poor Countries

Background

Measuring effectiveness of HIV prevention interventions is challenged by bias when using self-reported knowledge, attitude or behavior change. HIV incidence is an objective marker to measure effectiveness of HIV prevention interventions, however, because new infection rates are relatively low, prevention studies require large sample sizes. Herpes simplex virus type 2 (HSV-2) is similarly transmitted and more prevalent and could thus serve as a proxy marker for sexual risk behavior and therefore HIV infection.

Methods

HSV-2 antibodies were assessed in a sub-study of 70,000 students participating in an education intervention in Western Province, Kenya. Feasibility of testing for HSV-2 antibodies was assessed comparing two methods using Fisher’s exact test. Three hundred and ninety four students (aged 18 to 22 years) were randomly chosen from the cohort and tested for HIV, Chlamydia trachomatis, Neisseria gonorrhoeae, and Trichomonas vaginalis. Out of these, 139 students were tested for HSV-2 with ELISA and surveyed for sexual risk behavior and 89 students were additionally tested for HSV-2 with a point-of-contact (POC) test.

Results

Prevalence rates were 0.5%, 1.8%, 0.3% and 2.3% for HIV, Chlamydia trachomatis, Neisseria gonorrhoeae, and Trichomonas vaginalis, respectively. Prevalence of HSV-2 antibodies was 3.4 % as measured by POC test (n=89) and 14.4 % by ELISA (n=139). Specificity of the POC test compared with ELISA was 100%, and the sensitivity only 23.1%. Associations between self-reported sexual behavior and HSV-2 serostatus could not be shown.

Conclusions

Associations between self-reported sexual risk behavior and HSV-2 serostatus could not be shown, probably due to social bias in interviews since its transmission is clearly linked. HSV-2 antibody testing is feasible in resource-poor settings and shows higher prevalence rates than other sexually transmitted diseases thus representing a potential biomarker for evaluation of HIV prevention interventions.

Epidemiology, clinical features, diagnosis and treatment of Haemophilus ducreyi - a disappearing pathogen?

Chancroid, caused by Haemophilus ducreyi, has declined in importance as a sexually transmitted pathogen in most countries where it was previously endemic. The global prevalence of chancroid is unknown as most countries lack the required laboratory diagnostic capacity and surveillance systems to determine this. H. ducreyi has recently emerged as a cause of chronic skin ulceration in some South Pacific islands. Although no antimicrobial susceptibility data for H. ducreyi have been published for two decades, it is still assumed that the infection will respond successfully to treatment with recommended cephalosporin, macrolide or fluoroquinolone-based regimens. HIV-1-infected patients require careful follow-up due to reports of treatment failure with single dose regimens. Buboes may need additional treatment with either aspiration or excision and drainage.

Etiology of genital ulcer disease in a sexually transmitted infection reference center in Manaus, Brazilian Amazon

OBJECTIVES

To determine the etiology and factors associated with genital ulcer disease (GUD) among patients presenting to a sexually transmitted infections clinic in Manaus, Brazil; and to compare a multiplex polymerase chain reaction (M-PCR) assay for the diagnosis of GUD with standard methods.

METHODS

Ulcer swabs were collected and used for Tzanck test and processed in an M-PCR to detect herpes simplex virus (HSV-1/2), Treponema pallidum (T. pallidum), and Haemophilus ducreyi (H. ducreyi). Sera were tested for HIV and syphilis antibodies. Multivariable analysis was used to measure the association between clinical aspects and GUD. M-PCR results were compared with syphilis serology and Tzanck tests.

RESULTS

Overall, 434 GUD samples were evaluated, 84.8% from men. DNA from HSV-2 was detected in 55.3% of GUD samples, T. pallidum in 8.3%, HSV-1 in 3.2%, and 32.5% of GUD specimens were negative for the DNA of all three pathogens. No cases of H. ducreyi were identified. HIV serology among GUD patients was 3.2%. Treponemal antibodies and Tzanck test positivity for genital herpes was detected in 25 (5.8%) and in 125 (30.3%) of GUD patients, respectively. In multivariable analysis genital herpes etiology by M-PCR was associated with the vesicular, multiple and recurrent lesions whereas T. pallidum with non-vesicular, non-recurrent lesions. Compared to M-PCR, syphilis serology was 27.8% sensitive and 96.2% specific whereas Tzanck test was 43.8% sensitive and 88.9% specific.

CONCLUSIONS

The predominance of genital herpes etiology suggests a revision of existing national syndromic treatment guidelines in Brazil to include antiherpetic treatment for all GUD patients. The use of M-PCR can significantly improve the diagnosis of GUD and provide a greater sensitivity than standard diagnostics.

Prevalence and associations of genital ulcer and urethral pathogens in men presenting with genital ulcer syndrome to primary health care clinics in South Africa

BACKGROUND

This study aimed to determine the prevalence of genital ulcer and urethral pathogens, as well as their association with clinical features, in men with genital ulcer disease (GUD) enrolled in a clinical trial.

METHODS

Clinical data were collected by questionnaire. Ulcer swabs were tested for herpes simplex viruses (HSV-1/2), Treponema pallidum, Haemophilus ducreyi, and Chlamydia trachomatis L1-L3. First-pass urine was tested for urethral pathogens, namely Neisseria gonorrhoeae, C. trachomatis, Trichomonas vaginalis, and Mycoplasma genitalium. Pathogens were detected by real-time molecular assays. Blood was tested for HIV, HSV-2, and syphilis-associated antibodies. Pathogens and clinical associations were investigated using the χ test.

RESULTS

A total of 615 men with GUD were recruited. Herpes simplex virus (HSV-1, 4.2%; HSV-2, 98.2%) and bacterial pathogens were detected in 451 (73.6%) and 48 (7.8%) of genital ulcers, respectively. Human immunodeficiency virus, HSV-2, and treponemal antibodies were detected in 387 (62.9%), 434 (70.6%), and 141 (23.0%) men, respectively, whereas 54 men (8.8%) were rapid plasmin reagin (RPR) seropositive. A total of 223 urethral infections were diagnosed in 188 men (30.6%), including 69 (11.2%) M. genitalium, 64 (10.4%) T. vaginalis, 60 (9.8%) C. trachomatis, and 30 (4.9%) N. gonorrhoeae infections. Dysuria was reported by 170 men (27.6%), and 69 men (11.5%) had urethral discharge on examination. Urethral pathogens were detected in 102/409 (24.9%) men without these clinical features.

CONCLUSIONS

Herpes accounted for most GUD cases and urethral pathogen coinfections were common. Erythromycin, dispensed to treat infrequent chancroid and lymphogranuloma venereum cases, provided additional treatment of some asymptomatic urethral pathogens. Additional antibiotics would be required to treat asymptomatic trichomoniasis and gonorrhea.

The laboratory diagnosis of Haemophilus ducreyi

Chancroid is a sexually transmitted infection caused by Haemophilus ducreyi. This fastidious, Gram-negative coccobacilli dies rapidly outside the human host, making diagnostic testing using culture methods difficult. This genital ulcer infection is not common in Canada and, therefore, can often be misdiagnosed. The objective of the present paper is to provide practical approaches for the diagnosis of chancroid in Canadian patients where the prevalence of this infection is low. Issues related to sample collection, sample transport and available diagnostic tests are reviewed, and several alternative approaches are outlined. Although antigen detection, serology and genetic amplification methods have all been reported for H ducreyi, none are commercially available. Culture is still the primary method available to most laboratories. However, the special media necessary for direct bedside inoculation is often not available; therefore, communication with the diagnostic laboratory and rapid specimen transport are essential when chancroid is suspected.

Genital herpes testing among persons living with HIV

This cross-sectional survey explored the frequency of genital herpes testing among 110 people living with HIV (PLWH) and reported barriers and facilitators related to testing. Forty-four percent of the respondents had not been tested for genital herpes since receiving an HIV diagnosis, 34% had been tested, and 22% preferred not to say. Respondents' most frequently cited factors affecting a decision to not be tested were: (a) testing not being recommended by a provider, (b) not having herpes symptoms, and (c) not thinking they had herpes. Data from this study indicated that PLWH were not frequently tested for genital herpes; there was a limited understanding of the frequently subclinical nature of infection; and provider recommendations for testing, or lack thereof, affected testing decisions.

Recent advances in management of genital ulcer disease and anogenital warts

Genital ulcer disease (GUD) constitutes a major public health problem. Most of them are the result of sexually transmitted diseases. Genital herpes, syphilis, lymphogranuloma venereum, granuloma venereum, or chancroid are the commonly encountered GUD. The treatment modalities for these disorders have changed with advent and use of drugs such as azithromycin. The treatment modalities differ in patients with HIV disease. Further vaccines for herpes genitalis and human papilloma virus has opened new avenues in management of these diseases. In regions where there are no diagnostic facilities or where the costs of diagnostic tests are prohibitive, syndromic management of GUD is preferred.

Herpes simplex virus type 2: epidemiology and management options in developing countries

Genital herpes simplex virus type 2 (HSV2) is highly prevalent worldwide and an increasingly important cause of genital ulcer disease (GUD). Continued HSV2 transmission is facilitated by the large number of undiagnosed cases, the frequency of atypical disease and the occurrence of asymptomatic shedding. The lack of easy, affordable diagnostic methods and specific antiviral treatment in countries with low and middle income is of great concern, given the ability of GUD to enhance HIV transmission and acquisition. With rising HSV2 prevalence contributing to an increase in the proportion of GUD attributed to genital herpes in high-HIV prevalence settings, a safe and effective HSV vaccine is urgently needed. Meanwhile, multifaceted interventions are required to improve recognition of genital herpes, to prevent its spread and also to prevent its potential to promote HIV transmission in developing countries.

Treatment of chancroid in resource-poor countries

Chancroid, formerly a major cause of the genital ulcer disease syndrome, remains an important cofactor in both the transmission and acquisition of HIV-1 infection. Those countries with the greatest burden of HIV also have some of the highest prevalence rates of chancroid worldwide. The diagnosis of chancroid, caused by the fastidious bacterium Haemophilus ducreyi, is both expensive and difficult in many resource-poor areas. These areas of the world use syndromic management to treat genital ulcers and such an approach has proven effective in reducing rates of bacterial genital ulcer diseases. There are currently inexpensive and effective single-dose therapies available to treat chancroid. Single-dose regimens, given at first presentation, improve compliance and reduce the risk of sexually transmitted infections. Bacterial resistance to several antimicrobial agents has increased over the years and remains a continued threat to effective antimicrobial therapy. Follow-up of cases, and partner notification and treatment is carried out to limit reinfection and onward transmission of chancroid. Patients with coexistent HIV may be particularly at risk of failing single-dose therapy and should therefore be reviewed wherever possible.

Poor Correlation Between Genital Lesions and Detection of Herpes Simplex Virus in Women in Labor

OBJECTIVE

To estimate the accuracy of clinical diagnosis of genital herpes for herpes simplex virus (HSV) detection among women in labor.

METHODS

Viral detection by culture and HSV DNA polymerase chain reaction (PCR) among women who underwent cesarean delivery for genital herpes was compared with women without HSV symptoms in labor who had genital swabs collected for HSV culture and to a subset of these women who had genital specimens available for PCR analysis, regardless of culture results.

RESULTS

From 1989 to 1999, 126 of 19,568 (0.6%) women underwent cesarean delivery for HSV. Twenty-six percent of 110 of these women had HSV detected by culture from at least 1 genital specimen and 46% of 70 of these women had HSV detected by PCR. During the same period, 61 of 12,623 (0.5%) asymptomatic women had HSV detected by culture. Between 1995 and 1996, 57 of 2,109 (2.7%) asymptomatic women had HSV detected by PCR. Thus, the presence of genital lesions had a sensitivity for HSV detection of 37% by culture and 41% by PCR. The amount of HSV present in asymptomatic women with HSV detected in genital secretions by PCR was often as high as those with genital lesions, although the median amount of HSV DNA detected was greater in women with lesions.

CONCLUSION

Clinical diagnosis of genital herpes at the time of labor correlates relatively poorly with HSV detection from genital sites or lesions by culture or PCR and fails to identify asymptomatic women who have HSV in their genital secretions at the time of labor.

Chancroid: clinical manifestations, diagnosis, and management

Chancroid is a sexually transmitted disease (STD) caused by the Gram negative bacterium Haemophilus ducreyi and is characterised by necrotising genital ulceration which may be accompanied by inguinal lymphadenitis or bubo formation. H ducreyi is a fastidious organism which is difficult to culture from genital ulcer material. DNA amplification techniques have shown improved diagnostic sensitivity but are only performed in a few laboratories. The management of chancroid in the tropics tends to be undertaken in the context of syndromic management of genital ulcer disease and treatment is usually with erythromycin. A number of single dose regimens are also available to treat H ducreyi infection. Genital ulceration as a syndrome has been associated with increased transmission of human immunodeficiency virus (HIV) infection in several cross sectional and longitudinal studies. Effective and early treatment of genital ulceration is therefore an important part of any strategy to control the spread of HIV infection in tropical countries.

Development of a serological test for Haemophilus ducreyi for seroprevalence studies

We developed a new enzyme immunoassay (rpEIA) for use in determining the seroprevalence of chancroid. Three highly conserved outer membrane proteins from Haemophilus ducreyi strain 35000 were cloned, overexpressed, and purified from Escherichia coli for use as antigens in the rpEIA. Serum specimens from patients with and without chancroid were assayed to determine optimum sensitivity and specificity and to establish cutoff values. On the basis of these data, rpEIA was found to be both sensitive and specific when used to test a variety of serum specimens from patients with genital ulcers and urethritis and from healthy blood donors.

Human immunodeficiency virus infection and genital ulcer disease in South Africa: the herpetic connection

BACKGROUND AND OBJECTIVES

While genital ulcers are a risk factor in HIV infection, the association of specific agents of genital ulcer disease (GUD) with HIV infection may vary.

GOAL

To determine the etiology of GUD in HIV-infected and HIV-uninfected men attending sexually transmitted disease (STD) clinics in Durban, Johannesburg, and Cape Town, South Africa, and the association of previous and current sexually transmitted infections with HIV infection in men with ulcerative and nonulcerative STDs.

STUDY DESIGN

A cross-sectional study of 558 men with genital ulcers and 602 men with urethritis.

RESULTS

Patients with GUD were more likely to be infected with HIV than patients with urethritis (39.4% versus 21.4%, P< or =0.001). Herpes simplex virus 2 (HSV-2) was the most common agent identified in ulcer specimens (35.9%), and was detected in a significantly higher proportion of ulcer specimens from HIV-infected patients than in specimens from HIV-uninfected patients (47.4% versus 28.2%, P< or =0.001). Patients infected with HIV-1 were significantly more likely to have HSV-2 infection, as measured by the presence of the antibody to glycoprotein G-2, than patients not infected with HIV (63.1% versus 38.5%, P< or =0.001). Patients infected with HIV-1 were also significantly more likely to have initial HSV-2 infection than HIV-uninfected patients with GUD (50.0% versus 31.6%, P = 0.007). Haemophilus ducreyi was detected in 31.7% of ulcer specimens; prevalence did not vary by HIV-infection status. Treponema pallidum DNA was detected significantly less frequently in ulcer specimens from patients infected with HIV than in specimens from patients not infected with HIV (10.2% versus 26%, P< or =0.001); no association was found between HIV-infection status and fluorescent treponemal antibody absorption test seroreactivity, even when men with M-PCR-positive syphilis lesions were excluded from the analyses.

CONCLUSION

The authors found that HSV-2 is a more common etiology of GUD than has been suggested by previous studies conducted in South Africa; serologic evidence of HSV-2 infection and current cases of genital herpes are strongly associated with HIV infection among men who present to STD clinics with GUD or urethritis.

Etiology of genital ulcer disease in Dakar, Senegal, and comparison of PCR and serologic assays for detection of Haemophilus ducreyi

We used PCR assays to determine the etiology of genital ulcers in patients presenting to a sexually transmitted disease clinic in Dakar, Senegal, and evaluated the ability of two PCR tests (groEL and recD) and two serological tests (adsorption enzyme immunoassay [EIA] and lipooligosaccharide [LOS] EIA) to detect current Haemophilus ducreyi infection. We found that in this population, H. ducreyi, T. pallidum, and herpes simplex virus HSV DNA were detected in 56, 15, and 13% of 39 genital ulcer specimens, respectively, and H. ducreyi DNA was detected in 60% (3 of 5) of samples from ulcerated bubos. Among 40 consecutive patients with genital ulcer disease and with sufficient sample for both PCR assays, the recD and groEL H. ducreyi PCR assays were 83% concordant, with the recD PCR assay detecting six (15%) additional positive specimens and the groEL assay detecting one (3%) additional positive specimen. Compared to PCR, the adsorption EIA and LOS EIA tests had sensitivities of 71 and 59% and specificities of 57 and 90%, respectively, for the diagnosis of current H. ducreyi infection. While these differences in specificity could be due either to previous infection with H. ducreyi or to the detection of cross-reacting antibodies, only 6% of patients from a nearby family planning clinic gave a positive reaction in both the adsorption EIA and LOS EIA assays, indicating that cross-reacting antibodies are not prevalent among clinic attendees in this city. Our studies indicate that the adsorption EIA detects both current and past infection, while the LOS EIA assay is more specific for current infection with H. ducreyi in this population.

Chancroid: from clinical practice to basic science

Chancroid is a sexually transmitted disease caused by the bacterium Haemophilus ducreyi. It usually presents as a genital ulcer and may be associated with regional lymphadenopathy and bubo formation. H. ducreyi infection is predominantly seen in tropical resource-poor regions of the world where it is frequently the most common etiological cause of genital ulceration. Genital ulcer disease has been shown to be an extremely important co-factor in HIV transmission. With the advent of the AIDS epidemic, there has been increased research effort to elucidate those factors involved in the pathogenesis of chancroid. Several putative virulence factors have now been identified and isogenic H. ducreyi mutants constructed by mutagenesis of their encoding genes. This approach has facilitated investigations into the role each of these putative virulence factors may play in H. ducreyi pathogenesis through the use of in vitro and in vivo model systems. One major goal of current chancroid research is to identify antigens which are immunogenic and could form the basis of a vaccine against H. ducreyi infection. Such a vaccine, if shown to be effective in decreasing the prevalence of chancroid, could have the added benefit of slowing down the HIV incidence rates in those populations where chancroid is a major co-factor for HIV transmission.

The use of epidemiologic mass treatment and syndrome management for sexually transmitted disease control

BACKGROUND

Epidemiologic mass treatment and syndrome management are two sexually transmitted disease (STD) control strategies that are receiving increased attention internationally. The former is a population-based intervention, whereas the latter attempts to improve the quality and efficiency of clinic-based STD case management.

METHODS

The published literature on these subjects was reviewed.

RESULTS

Epidemiologic mass treatment refers to treatment of whole communities (mass treatment) or high-risk subgroups within communities (targeted presumptive treatment) based on high STD prevalence rates. Syndrome management overcomes many obstacles to provision of quality STD case management by basing treatment decisions on recognition of easily identifiable syndromes. Experience with application of these strategies is summarized, and their possible use as STD control measures in communities with similar conditions is discussed.

CONCLUSIONS

Epidemiologic mass treatment may be an effective approach to rapidly reduce STD transmission in high prevalence communities, especially when high-risk core groups are effectively reached. Once high prevalence rates are brought down, however, longer term strategies, including improved STD case management, are essential to maintain reduced rates.

Syndromic management of sexually transmitted diseases: is it rational or scientific?

Control of sexually transmitted diseases improves the reproductive and sexual health of afflicted individuals and lowers the community burden of HIV. Preventing STDs or their complications requires health education, condom promotion and effective case management. Clinical diagnosis is frequently incorrect while laboratory-confirmed aetiological diagnosis is expensive. In resource-poor countries which lack trained personnel and laboratory facilities, syndromic management remains a rational approach to STD care. Although the approach is simplistic in design, its successful implementation requires regular monitoring and evaluation of protocols as well as supervision and training of clinicians.

The rrs (16S)-rrl (23S) ribosomal intergenic spacer region as a target for the detection of Haemophilus ducreyi by a heminested-PCR assay

The intergenic spacer region between the rrs and rrl ribosomal RNA genes of Haemophilus ducreyi was analysed and the DNA sequence was used for the selection of specific PCR primers. A highly sensitive and specific heminested-PCR assay for the identification of H. ducreyi was developed. The assay showed a sensitivity of 96% on genital ulcer specimens from patients with clinically diagnosed chancroid, compared with a sensitivity of 56% for culture methods. These results indicate that this PCR assay has the potential to become an accurate and easy reference method for the detection of H. ducreyi.

Polymerase chain reaction detection of Haemophilus ducreyi DNA

OBJECTIVES

To develop a polymerase chain reaction (PCR) method to detect Haemophilus ducreyi DNA in cultured isolates and clinical material.

METHODS

Primers specific to the H ducreyi 16s rRNA gene were synthesised. PCR conditions were optimised and products were verified by restriction endonuclease digestion and agarose gel electrophoresis.

RESULTS

The method was able to detect all 28 H ducreyi strains tested; specificity was demonstrated using lysates of 12 related organisms. Applied to clinical samples from genital ulcer swabs obtained in Harare, Zimbabwe, H ducreyi DNA was detected in repeated assays in 35 clinical samples.

CONCLUSION

PCR amplification using primers from the 16s rRNA gene may be a useful alternative to culture for the detection of H ducreyi and the diagnosis of chancroid.

The impact of antimicrobial resistance on the treatment of sexually transmitted diseases

The focus of this article is to review the development of antimicrobial resistance among several sexually transmitted diseases (STDs) and to discuss the frequency and mechanisms of resistance and recommendations for treatment of selected STDs in which resistance to certain antimicrobial agents has increased. For a number of STDs, such as Chlamydia trachomatis and syphilis, no evidence of antimicrobial resistance has developed over the years, although management of these diseases, such as in the case of pelvic inflammatory disease or syphilis in HIV-infected individuals, requires intensive treatment and follow-up to ensure effectiveness of treatment.

Sexually transmitted diseases in South Africa

AIM

To review the epidemiology of and data collection for sexually transmitted diseases (STDs) in South Africa.

METHODS

Literature published since 1980 on STDs in South Africa were complied and evaluated. Historical reports and salient unpublished literature were also used in the literature review. Studies were critically reviewed in the light of sample populations and study methods, and a baseline picture of the patterns of STD burden was developed.

RESULTS

The STD burden in apparently asymptomatic study populations is significant. Ulcerative infections, primarily caused by syphilis and chancroid, are present in 5-15% of asymptomatic clinic attenders; prevalence rates of gonorrhoea average 8%, with up to 13% of gonococcal isolates resistant to penicillin antibiotics. In addition, on average, chlamydia and vaginal infections are detected in 16% and 20-49%, respectively, of antenatal and family planning clinic attenders. HIV seroprevalence rates have reached 7.6% in antenatal clinic attenders. Most South African STD data are derived from ad hoc surveys which have traditionally focused only on several major infections and particular urban centres. Almost all STD studies have been facility-based, with many studies based at STD clinics, thus reporting only relative frequencies and not population-based prevalences of STDs. With the possible exception of HIV, systematic surveillance data for STDs are conspicuously lacking.

CONCLUSION

The disease burden of classic sexually transmitted infections has historically been heavy, and continues to be a serious public health problem in South Africa. Morbidity from both ulcerative and non-ulcerative infections, particularly in women, is significant. The body of STD data, although mostly sound, remains incomplete, and with the rapid emergence of HIV in South Africa, surveillance of STDs and focused STD policies will be critical.

Monoclonal antibodies against Haemophilus ducreyi lipooligosaccharide and their diagnostic usefulness

Monoclonal antibodies against the lipooligosaccharide of Haemophilus ducreyi were produced. Two of them, MAHD6 and MAHD7, were found to be relatively, although not absolutely, specific and reacted with nearly all strains of Haemophilus ducreyi tested: 59 of 60 and 60 of 60, respectively. The diagnostic usefulness of MAHD7 was assessed. Clinical specimens collected in Zambia from patients with genital ulcers were tested using indirect immunofluorescence (IF), enzyme immunoassay (EIA), the polymerase chain reaction (PCR) and bacterial culture. Compared with culture, IF had a sensitivity of 100%; compared with PCR, sensitivity was 89%. The corresponding figures for the EIA were 83% and 74%, respectively. The sensitivity of culture compared with PCR was 63%. The results suggest that IF on genital smears using MAHD7 might be an excellent tool for the diagnosis of chancroid in high-prevalence populations. However, further evaluation of the specificity of this test is needed.

Detection of Haemophilus ducreyi lipooligosaccharide by means of an immunolimulus assay

A murine monoclonal antibody (MAb) directed against a surface-exposed epitope of the lipooligosaccharide (LOS) of Haemophilus ducreyi strain 35000 was shown to be reactive with all 37 strains of this pathogen tested in a colony blot-radioimmunoassay. The LOS epitope bound by this MAb appeared to be stably expressed by H. ducreyi growing in vitro. The use of this MAb in the immunolimulus system revealed that it could detect purified H. ducreyi LOS at a level of 25 pg/ml. Similarly, this immunolimulus system could detect as few as 1000 colony forming units of in vitro-grown H. ducreyi cells per ml of buffer. When this MAb was utilized in the immunolimulus system together with lesion material from rabbits infected with two different H. ducreyi strains, a positive reaction was obtained with every sample tested, even when no viable organisms were present in the lesion material. In contrast, this MAb yielded consistently negative results when used in the immunolimulus system with lesion material from animals infected with Staphylococcus aureus.

Asymptomatic carriage of Haemophilus ducreyi confirmed by the polymerase chain reaction

OBJECTIVE

To investigate asymptomatic carriage of Haemophilus ducreyi by using polymerase chain reaction (PCR) on samples from women at high risk of infection.

SUBJECTS

213 commercial sex workers (CSWs) recruited in The Gambia, West Africa.

METHODS

Genital samples (cervical, vaginal and ulcer) were tested for the presence of H ducreyi by PCR with the technique of "one tube nested primer".

RESULTS

12 CSWs were PCR positive for H ducreyi; 8 of these women had genital ulcers on examination.

CONCLUSION

Using a simplified PCR technique for detecting H ducreyi we have shown that 2% of CSWs were carrying the organism without clinical symptoms or signs. This has important implications for sexually transmitted disease control programmes in areas with a high prevalence of chancroid.

Chancroid and Haemophilus ducreyi: an update

Haemophilus ducreyi is a fastidious gram-negative bacillus that causes the sexually transmitted infection chancroid. Chancroid is a major genital ulcerative disease in Africa, Southeast Asia, the Caribbean, and Latin America and is of increasing concern in the United States. Genital ulcerative disease and chancroid in particular have been associated with facilitating the transmission of human immunodeficiency virus. The diagnosis of chancroid based on the clinical appearance of the genital lesion or on the isolation of H. ducreyi on selective medium is relatively insensitive. However, recent advances in nonculture diagnostic tests have enhanced our ability to diagnose chancroid. There has been renewed interest in understanding the pathogenesis of H. ducreyi. In vitro and in vivo models have been developed to help identify important virulence determinants. Through the use of biochemical and molecular techniques, macromolecular components that may be important in virulence have been identified.

Simplified PCR for detection of Haemophilus ducreyi and diagnosis of chancroid

A simplified PCR was developed for detection of Haemophilus ducreyi in samples from chancroid patients. The strategy included a straightforward chloroform extraction sample preparation method, a one-tube nested PCR to minimize contamination risks, and a colorimetric method for detection of products. Primers were designed from published nucleotide sequences of the 16S rRNA gene of H. ducreyi, with longer outer primers for annealing at a higher temperature and shorter inner primers labelled with biotin and digoxigenin for binding with avidin and colorimetric detection. The PCR technique detected all 35 strains of H. ducreyi tested, from four different geographical regions, and was negative for other, related strains of bacteria and for the common contaminating bacteria tested. Of 25 samples from H. ducreyi culture-positive chancroid patients, 24 were PCR positive and 1 produced a weak reaction. Of 83 samples from clinical cases of chancroid in the Republic of South Africa, 69 were PCR positive. The sensitivity of PCR compared with that of clinical diagnosis was 83%. All 50 negative control samples were negative. Encouraging results were also obtained with a consecutive series of 25 genital ulcer patients in Tanzania, of whom 9 were PCR positive. The adaptations of this simplified PCR strategy, at the sensitivity and specificity levels obtained, mean it will be useful for detection of H. ducreyi in areas where the organism is endemic, particularly where testing by culture is difficult or impossible.

Development of the polymerase chain reaction for diagnosis of chancroid

The published nucleotide sequences of the 16S rRNA gene of Haemophilus ducreyi were used to develop primer sets and probes for the diagnosis of chancroid by polymerase chain reaction (PCR) DNA amplification. One set of broad specificity primers yielded a 303-bp PCR product from all bacteria tested. Two 16-base probes internal to this sequence were species specific for H. ducreyi when tested with 12 species of the families Pasteurellaceae and Enterobacteriaceae. The two probes in combination with the broad specificity primers were 100% sensitive with 51 strains of H. ducreyi isolated from six continents over a 15-year period. The direct detection of H. ducreyi from 100 clinical specimens by PCR showed a sensitivity of 83 to 98% and a specificity of 51 to 67%, depending on the number of amplification cycles.