Point-of-care testing for sexually transmitted infections in low-resource settings.

BACKGROUND: Both the global incidence and the prevalence of sexually transmitted infections (STIs) continue to increase, affecting hundreds of millions of individuals, particularly in low-to middle-income countries. Although a definitive diagnosis is desirable to inform STI treatment, syndromic management is the most widely used strategy in resource-limited settings. With the development of point-of-care (POC) tests, it is important to discuss how laboratories will need to adapt to new training and supervisory roles in support of testing, which will largely be performed by peripheral clinical staff. OBJECTIVES: To discuss potential applications of STI POC tests, how they could improve existing STI control strategies and the role of clinical and reference laboratories in support of initiatives to improve STI management and control activities. SOURCES: Narrative literature review and expert opinion. CONTENT: The paper outlines the current status of the STI epidemic worldwide and discusses the problems associated with current approaches to control these infections, particularly in low-resource settings. The roles of clinical and reference laboratories will need to change to provide support for POC and near-patient STI testing as these technologies are introduced into clinical as well as laboratory settings. IMPLICATIONS: Laboratories will be expected to play a leading role in the introduction and implementation of POC and near-patient STI testing. They will be required to facilitate training and provide technical and supervisory support to clinical staff on the use of these technologies to augment existing STI management and surveillance programmes. In order to provide quality service, they will need to develop, introduce and maintain sustainable local quality control and external quality assurance systems. Evidence from implementation research for introduction and scale up of STI POC tests in different STI epidemic and laboratory infrastructure settings is required.

Analytical evaluation of nine serological assays for diagnosis of syphilis.

BACKGROUND: The diagnosis of syphilis is most frequently dependent on antibody detection with serological assays. Assays for both treponemal and non-treponemal antibodies are needed to provide a sensitive and specific diagnosis. For decades, a first screening has been done with non-treponemal assays, followed by treponemal. However, in recent years, following laboratory automation, the reverse sequence screening algorithms have been developed, using a treponemal assay as the initial screening test. OBJECTIVE: To evaluate serological assays for treponemal and non-treponemal antibodies, to use in reverse algorithm screening of syphilis. MATERIAL AND METHODS: Six treponemal assays (one IgM-specific assay), two non-treponemal assays and one novel dual point-of-care (POC) assay for serological diagnosis of syphilis were evaluated. Serum samples from Guinea-Bissau and Sweden were examined, as well as two performance panels and samples from blood donors. Sensitivity and specificity were calculated for each assay, using different assays as gold standard test. RESULTS: The Macro-Vue RPR Card test was the most sensitive non-treponemal test and the TrepSure Anti-Treponema EIA Screen and the SeroDia TP-PA were the most sensitive and specific treponemal assays. Among the automated assays, both the Liaison Treponema Screen and Architect Syphilis TP showed high sensitivity, however, the former had clearly higher specificity. CONCLUSIONS: In resourced settings, where the reverse sequence algorithm is preferred for screening, an automated treponemal immunoassay for initial screening subsequently followed by the TrepSure test or TP-PA assay as a second treponemal assay appear highly effective. Finally, a quantitative highly sensitive non-treponemal assay, e.g. the Macro-Vue RPR Card test, could then be used as a supplementary test to evaluate activity of the syphilis infection.

Evaluation of polymerase chain reaction assays for the diagnosis of Trichomonas vaginalis infection in Russia.

BACKGROUND: In Russia, the microscopy- and culture-based diagnostics of trichomoniasis is mainly suboptimal. Recent years, domestically produced diagnostic PCR assays have been implemented; however, any evaluation of these PCRs has never been internationally reported. OBJECTIVE: To assess the performance characteristics of PCR assays developed and currently used in Russia to detect Trichomonas vaginalis. MATERIALS AND METHODS: Five PCR assays were assessed on 448 samples (317 vaginal and 131 male urethral) collected from symptomatic attendees of youth centres (n = 415) and patients of a dermatovenereological dispensary that were previously diagnosed with trichomoniasis (n = 33). As reference assay, a sensitive and specific real-time multiplex PCR was used. RESULTS: T. vaginalis DNA was detected in five (all females) of the 415 patients of youth centres (1.2%). All 33 patients previously diagnosed at the venereological dispensary proved to be true positive. For 445 (99.3%) of these 448 samples identical results were obtained by all PCRs, 35 positive and 410 negative. The three discordant samples were positive in all PCRs except one conventional PCR assay. The sensitivities of the PCRs were 94.3-100% and 66.7-100% for vaginal and urethral swabs, respectively. All evaluated assays were 100% specific. The detection limits of the different PCRs ranged from 0.1 to 5 genome equivalents per reaction. CONCLUSION: The PCR assays currently used in Russia for the detection of T. vaginalis have in general high sensitivities and excellent specificities for both vaginal samples and urethral samples from males.

Identifying abnormalities in symbiotic development between Trifolium spp. and Rhizobium leguminosarum bv. trifolii leading to sub-optimal and ineffective nodule phenotypes.

BACKGROUND AND AIMS: Legumes overcome nitrogen limitations by entering into a mutualistic symbiosis with N(2)-fixing bacteria (rhizobia). Fully compatible associations (effective) between Trifolium spp. and Rhizobium leguminosarum bv. trifolii result from successful recognition of symbiotic partners in the rhizosphere, root hair infection and the formation of nodules where N(2)-fixing bacteroids reside. Poorly compatible associations can result in root nodule formation with minimal (sub-optimal) or no (ineffective) N(2)-fixation. Despite the abundance and persistence of strains in agricultural soils which are poorly compatible with the commercially grown clover species, little is known of how and why they fail symbiotically. The aims of this research were to determine the morphological aberrations occurring in sub-optimal and ineffective clover nodules and to determine whether reduced bacteroid numbers or reduced N(2)-fixing activity is the main cause for the Sub-optimal phenotype. METHODS: Symbiotic effectiveness of four Trifolium hosts with each of four R. leguminosarum bv. trifolii strains was assessed by analysis of plant yields and nitrogen content; nodule yields, abundance, morphology and internal structure; and bacteroid cytology, quantity and activity. KEY RESULTS: Effective nodules (Nodule Function 83-100 %) contained four developmental zones and N(2)-fixing bacteroids. In contrast, Sub-optimal nodules of the same age (Nodule Function 24-57 %) carried prematurely senescing bacteroids and a small bacteroid pool resulting in reduced shoot N. Ineffective-differentiated nodules carried bacteroids aborted at stage 2 or 3 in differentiation. In contrast, bacteroids were not observed in Ineffective-vegetative nodules despite the presence of bacteria within infection threads. CONCLUSIONS: Three major responses to N(2)-fixation incompatibility between Trifolium spp. and R. l. trifolii strains were found: failed bacterial endocytosis from infection threads into plant cortical cells, bacteroid differentiation aborted prematurely, and a reduced pool of functional bacteroids which underwent premature senescence. We discuss possible underlying genetic causes of these developmental abnormalities and consider impacts on N(2)-fixation of clovers.

Pilot trial of late booster doses of surfactant for ventilated premature infants.

OBJECTIVE: Many premature infants at risk for bronchopulmonary dysplasia experience episodes of surfactant dysfunction with reduced surfactant protein B (SP-B). In this study, we investigated the safety and responses to booster doses of surfactant. STUDY DESIGN: A total of 87 infants, 500 to 1250 g birth weight, who were ventilated at 7 to 10 days received 2 or 3 doses of Infasurf (Calfactant, Forest Pharmaceuticals, St Louis, MO, USA) within a 1-week period. RESULT: For 184 doses, occurrence rates of transient bradycardia (13) and plugged endotracheal tube (5) were low, and no other adverse effects were noted. Treatment transiently improved the respiratory severity score (FiO(2) × mean airway pressure), SP-B content (+75%) and surface properties of isolated surfactant. Levels of eight proinflammatory cytokines in tracheal aspirate were interrelated and unchanged from baseline after surfactant treatment. CONCLUSION: Booster doses of surfactant for premature infants with lung disease are safe and transiently improve respiratory status as well as composition and function of endogenous surfactant.

Guidelines for the laboratory diagnosis of genital herpes in eastern European countries.

These guidelines aim to provide comprehensive information about sexually transmitted herpes simplex virus (HSV) infection and its laboratory diagnosis in eastern European countries. They are primarily intended for professionals testing specimens from patients at a sexual healthcare clinic but may also be helpful for community-based screening programmes. In particular, the guidelines recommend: (i) either viral culture or validated and approved nucleic acid amplification tests (NAATs) as the tests of choice for symptomatic patients, which should be promoted for laboratory confirmation of HSV infection; (ii) if culture or NAATs are not available, antigen detection--a direct immunofluorescence test or enzyme immunoassay from samples from symptomatic patients--could be employed, but HSV type determination is of importance; (iii) only type-specific serology should be used for detecting asymptomatic individuals, testing pregnant women at risk of acquiring HSV infection close to delivery, men who have sex with men and people who are HIV positive; (iv) widespread screening for HSV antibodies should be discouraged; and (v) any non-validated diagnostic tests should be validated against a recommended, approved gold standard.

An immunofiltration device for the simultaneous detection of non-treponemal and treponemal antibodies in patients with syphilis.

OBJECTIVE: The development of a rapid immunofiltration (flow-through) test for the simultaneous detection of non-treponemal and treponemal antibodies in the serum of patients with syphilis. METHODS: The assay is rapid, inexpensive, and requires limited expertise in interpreting the results. The test is based on the principle of immunofiltration, with two antigens and control material spotted on the membrane of a through-flow device. A positive test is characterised by the appearance of three red/magenta spots within 2-10 min. RESULTS: A total of 376 banked serum samples obtained from the Georgia Public Health Laboratory was examined by the flow-through test, the rapid plasma reagin (RPR) test and the Treponema pallidum passive particle agglutination assay (TPPA). The sensitivity and specificity of the non-treponemal spot were 96.5% and 97.7%, respectively, when compared with the RPR test, and the sensitivity and specificity of the treponemal test spot were 97.3% and 99.1% when compared with the TPPA test. In addition, the test yielded equivalent results to those obtained in comparator tests when 104 sera from cases of syphilis of known stage, 49 sera from diseases other than syphilis and 23 sera known to exhibit biological false-positive reactions were tested in parallel. CONCLUSIONS: These results indicate that the dual treponemal and non-treponemal assay could be used as a screen and confirmatory test for the serological diagnosis of syphilis in remote or resource-poor settings where there is a need to provide counselling and treatment at the initial consultation.

Guidelines for the laboratory diagnosis of trichomoniasis in East European countries.

The laboratory diagnosis of sexually transmitted infections in many Eastern European countries remains suboptimal. The main objective of the present evidence-based guidelines is to provide comprehensive information regarding the laboratory diagnosis of infections caused by Trichomonas vaginalis in East European countries. In particular, the present guidelines recommend: (i) to encourage examination of the wet mounts of vaginal exudates, instead of stained smears, at all clinical settings; (ii) nucleic acid amplification tests (NAATs) or culture could be employed if no trichomonads are detected on microscopic examination of the wet preparation and there is a strong indication of infection and (iii) the use of NAATs is encouraged in screening, using non-invasive specimens, or high volume testing situations. In the absence of internationally recognized commercial NAAT systems, tests developed in-house should be validated using obtainable international standards and quality assured strictly. Individual East European countries may be required to make minor national adjustments to these guidelines as a result of lack of accessibility to some reagents or equipment, or laws in a specific country.

Inhaled nitric oxide in premature infants: effect on tracheal aspirate and plasma nitric oxide metabolites.

OBJECTIVE: Inhaled nitric oxide (iNO) is a potential new therapy for prevention of bronchopulmonary dysplasia and brain injury in premature infants. This study examined dose-related effects of iNO on NO metabolites as evidence of NO delivery. STUDY DESIGN: A subset of 102 premature infants in the NO CLD trial, receiving 24 days of iNO (20 p.p.m. decreasing to 2 p.p.m.) or placebo, were analyzed. Tracheal aspirate (TA) and plasma samples collected at enrollment and at intervals during study gas were analyzed for NO metabolites. RESULT: iNO treatment increased NO metabolites in TA at 20 and 10 p.p.m. (1.7- to 2.3-fold vs control) and in plasma at 20, 10, and 5 p.p.m. (1.6- to 2.3-fold). In post hoc analysis, treated infants with lower metabolite levels at entry had an improved clinical outcome. CONCLUSION: iNO causes dose-related increases in NO metabolites in the circulation as well as lung fluid, as evidenced by TA analysis, showing NO delivery to these compartments.

Laboratory support for the diagnosis and surveillance of sexually transmitted infections (STIs) in Eastern Europe.

This report outlines the proceedings of the 4th Annual Meeting of the Eastern European Network for Sexual and Reproductive Health (EE SRH Network) [1,2], which took place at Uppsala University in Uppsala, Sweden between 30 May and 3 June, 2009.

Guidelines for the laboratory diagnosis of Chlamydia trachomatis infections in East European countries.

The present guidelines aim to provide comprehensive information regarding the laboratory diagnosis of infections caused by Chlamydia trachomatis in East European countries. These recommendations contain important information for laboratory staff working with sexually transmitted infections (STIs) and/or STI-related issues. Individual East European countries may be required to make minor national adjustments to these guidelines as a result of lack of accessibility to some reagents or equipment, or laws in a specific country.

Guidelines for the laboratory diagnosis of syphilis in East European countries.

The present guidelines aim to provide comprehensive and precise information regarding the laboratory diagnosis of the sexually transmitted infection (STI) syphilis in East European countries. These recommendations contain important information for laboratory staff working with STIs and/or STI-related issues. Individual East European countries may be required to make minor national adjustments to these guidelines as a result of lack of accessibility to some reagents or equipment, or laws in a specific country.

Laboratory diagnostics for non-viral sexually transmitted infections in St. Petersburg, Russia: current situation and hallmarks for improvements.

BACKGROUND: The numbers and performance characteristics of laboratories providing sexually transmitted infection (STI) diagnostic services, as well as the rates of morbidity due to STIs in St. Petersburg, Russia, remain largely unknown. OBJECTIVE: The aim of the present study was to evaluate the range, quality and availability of diagnostic services for several non-viral STIs (Chlamydia trachomatis, Neisseria gonorrhoeae, Treponema pallidum and Trichomonas vaginalis) in St. Petersburg during the period September 2005 to June 2006. METHODS: Survey data focusing on organization and performance characteristics of STI diagnostic services were assessed using questionnaires, telephone interviews and site visits. RESULTS: A total of 118 laboratories providing STI diagnostic services were identified. Of the surveyed laboratories, 54% (64 of 118) diagnosed syphilis, 81% (96 of 118) gonorrhoea, 80% (94 of 118) trichomoniasis and 49% (58 of 118) chlamydial infections. Although most of the laboratories could provide a presumptive diagnosis for syphilis, most of the N. gonorrhoeae and T. vaginalis testing of women did not adhere to international recommendations. Of the laboratories with the capacity to diagnose C. trachomatis infection, 69% still used serological testing (enzyme-linked immunosorbent assay) to detect antibodies to C. trachomatis. CONCLUSIONS: Overall, the diagnostic methods used to establish a laboratory diagnosis, the system of case reporting, the training of laboratory personnel and the level of interlaboratory communication clearly require improvement. This study represents the first step in a process of evaluation of the laboratory support for STI services and the establishment of an interlaboratory network in St. Petersburg.

A real-time quadriplex PCR assay for the diagnosis of rectal lymphogranuloma venereum and non-lymphogranuloma venereum Chlamydia trachomatis infections.

OBJECTIVES: To develop and evaluate a real-time quadriplex PCR for the diagnosis of lymphogranuloma venereum (LGV) and non-LGV chlamydial infections using rectal swab specimens. METHODS: The design of the real-time quadriplex PCR assay incorporates an LGV-specific, a non-LGV-specific target sequence, a Chlamydia trachomatis plasmid target, and the human RNase P gene as an internal control. The performance of the quadriplex PCR was compared with a previously reported real-time duplex PCR assay on which LGV diagnosis was based on exclusion. RESULTS: Very good agreement (85 of 89 specimens, 95.5%) was found between the two multiplex PCR assays for the detection of C trachomatis DNA (kappa value 0.93, 95% CI 0.86 to 0.99). Both assays identified 34 LGV, 35 non-LGV C trachomatis and 16 negative specimens. Of two specimens that tested positive for non-LGV by the duplex PCR, one was found to be a mixed infection and the other was positive only for plasmid and RNase P targets by the quadriplex PCR. Two additional specimens that had equivocal results for non-LGV by the duplex PCR also tested positive only for plasmid target and human DNA by the quadriplex PCR. In addition, six specimens that tested negative by the duplex PCR assay were found to be invalid when using the quadriplex PCR. CONCLUSIONS: A real-time quadriplex PCR assay has been developed that is capable of detecting LGV, non-LGV, or mixed infections simultaneously in rectal specimens. The assay also contains a supplemental amplification target for the confirmation of C trachomatis infection as well as a human DNA control for monitoring sample adequacy and PCR inhibition.

The effect of inhaled nitric oxide on pulmonary function in preterm infants.

OBJECTIVE: Bronchopulmonary dysplasia (BPD) in preterm infants is associated with impaired alveolar growth, inflammation and airway hyperreactivity. In animal models of BPD, inhaled nitric oxide (NO) improves alveolar growth and inhibits airway smooth muscle proliferation. This study was designed to assess the effect of inhaled NO on resistance and compliance in ventilated preterm infants with evolving BPD. STUDY DESIGN: Expiratory resistance and compliance of the respiratory system were measured in 71 ventilated preterm infants, < or = 32 weeks gestation, randomized to NO (n=34) versus placebo (n=37) for > or = 24 days at 7 to 21 days of life. RESULT: At baseline expiratory resistance (231+/-71 versus 215+/-76 cm H(2)O l(-1) s(-1)) and compliance (0.49+/-0.14 versus 0.53+/-0.13 ml cm H(2)O(-1) kg(-1)) were comparable between placebo and NO groups, respectively. There was no effect of NO on expiratory resistance or compliance at 1 h, 1 week or 2 weeks of study gas administration. CONCLUSION: NO had no short- or medium-term effect on expiratory resistance or compliance in ventilated preterm infants.

Comparison of a TaqMan-based real-time polymerase chain reaction with conventional tests for the detection of Trichomonas vaginalis.

OBJECTIVE: To compare a TaqMan-based real-time polymerase chain reaction (PCR) with conventional PCR, culture, and wet-mount microscopy for the diagnosis of trichomoniasis in women. METHODS: Vaginal swabs from 119 women were tested for Trichomonas vaginalis by wet mount and culture. Paired vaginal lavage and urine specimens were tested by conventional and real-time PCR. RESULTS: Using an expanded "gold standard", defined as a positive culture result using vaginal swabs and/or a positive PCR test using TVK3/7 primers, the overall prevalence of T vaginalis in the study population was 65.5% (78/119). The detection rate of T vaginalis was 65.5% (78/119) and 36.9% (44/119) by conventional PCR using vaginal washings and urine specimens, respectively; 68.9% (82/119) by real-time PCR using vaginal washings and 61.3% (73/119) by real-time PCR using urine specimens. The sensitivities of conventional PCR using vaginal washings and urine and real-time PCR using vaginal washings and urine, compared with the gold standard were 100%, 56.4%, 100% and 76.7%, and the specificities of these tests were 100%, 97.6%, 82.9% and 97%, respectively. CONCLUSIONS: The real-time PCR test proved to be significantly more sensitive than culture and wet-mount microscopy, although its specificity was slightly lower than these tests. In addition, it was more sensitive, rapid and less time consuming than conventional PCR for the detection of T vaginalis.

The influence of concomitant HIV infection on the serological diagnosis of primary syphilis in southern Africa.

The authors investigated the utility of both a nontreponemal (RPR) test and a treponemal (FTA-ABS) test for the diagnosis of primary syphilis during the emergence of the HIV epidemic in southern Africa. The serological tests were performed on 868 patients with genital ulcerations, seen in five centres. While primary syphilis was diagnosed by multiplex PCR in 163 cases (18.8%), the overall RPR and FTA-ABS seroprevalences were 24.3% and 51.5% respectively. The sensitivities of the RPR and FTA-ABS to detect primary syphilis were 69.3% and 89.6% respectively, while the specificities were 86.1% and 58.5% respectively. The performance characteristics of these tests were influenced negatively by concomitant HIV infection and the presence of other genital ulcer disease pathogens in lesions found to be Treponema pallidum PCR positive.