The application of multiplex PCR to detect seven different DNA targets in group B streptococci

Group B Streptococcus (GBS) causes severe infections in infants and in immunocompromised adults. GBS pathogenicity varies between and within serotypes, with considerable variation in genetic content between strains. For this reason, it is important to be able to carry out immediate and comprehensive diagnostics of these infections. Seven genes important for screening of GBS infection were detected: cfb gene encoding the CAMP factor presented in every GBS; the cps operon genes such as cps1aH, cps1a/2/3IJ, and cps5O specific for capsular polysaccharide types Ia, III, and V, respectively; macrolide resistance genes ermB and mefA/E; and the gbs2018 S10 region specific for ST17 hypervirulent clone. Standardization of multiplex PCR with the use of seven primer pairs was performed on 81 bacterial strains representing different GBS isolates (n = 75) and other Gram-positive cocci (n = 10). Multiplex PCR can be used as an effective screening method to detect different sequences important for the screening of GBS infection

Acquired homotypic and heterotypic immunity against oculogenital Chlamydia trachomatis serovars following female genital tract infection in mice

BACKGROUND: Chlamydia trachomatis is the most common sexually transmitted bacterial pathogen causing female genital tract infection throughout the world. Reinfection with the same serovar, as well as multiple infections with different serovars, occurs in humans. Using a murine model of female C. trachomatis genital tract infection, we determined if homotypic and/or heterotypic protection against reinfection was induced following infection with human oculogenital strains of C. trachomatis belonging to two serovars (D and H) that have been shown to vary significantly in the course of infection in the murine model. METHODS: Groups of outbred CF-1 mice were reinfected intravaginally with a strain of either serovar D or H, two months after initial infection with these strains. Cellular immune and serologic status, both quantitative and qualitative, was assessed following initial infection, and the course of infection was monitored by culturing vaginal samples collected every 2–7 days following reinfection. RESULTS: Serovar D was both more virulent (longer duration of infection) and immunogenic (higher level of circulating and vaginal IgG and higher incidence of IgA in vaginal secretions) in the mouse genital tract. Although both serovars induced cross-reacting antibodies during the course of primary infection, prior infection with serovar H resulted in only a slight reduction in the median duration of infection against homotypic reinfection (p ~ 0.10), while prior infection with serovar D resulted in significant reduction in the median duration of infection against both homotypic (p < 0.01) and heterotypic reinfection (p < 0.01) when compared to primary infection in age and conditions matched controls. CONCLUSION: Serovar D infection resulted in significant homotypic and heterotypic protection against reinfection, while primary infection with serovar H resulted in only slight homotypic protection. In addition to being the first demonstration of acquired heterotypic immunity between human oculogenital serovars, the differences in the level and extent of this immunity could in part explain the stable difference in serovar prevalence among human isolates

Urine-based testing for Chlamydia trachomatis among young adults in a population-based survey in Croatia: Feasibility and prevalence

<p>Abstract</p> <p>Background</p> <p>We assessed the feasibility of collecting urine samples for testing on genital <it>Chlamydia trachomatis </it>infection in a population-based survey, and prevalence of this infection among young people aged 18-25 in Croatia. In Croatia, as in the other countries of Eastern Europe, there is a lack of data on prevalence of <it>C trachomatis </it>in the general population, including young adults.</p> <p>Methods</p> <p>We sampled participants using a nationally representative, multi-stage stratified probability sample of young men and women. Detection of <it>C trachomatis </it>DNA in urine samples was performed by using a real-time PCR assay COBAS^®TaqMan^®CT Test, v2.0.</p> <p>Results</p> <p>Overall, 1005 young adults participated in the behavioural part of the survey, and 27.9% men and 37.5% women who were sexually experienced agreed to provide urine samples for testing on <it>C trachomatis</it>. Using multivariate analysis, women were significantly more likely to provide urine samples than men (aOR = 1.53, 95% CI 1.14-2.06) as were those who reported no condom use at last intercourse (aOR = 1.95, 95% CI 1.44-2.62). Prevalence of <it>C trachomatis </it>infection among those who were sexually experienced was 7.3% in men and 5.3% in women.</p> <p>Conclusions</p> <p>Population-based surveys that use probabilistic sampling are a feasible way to obtain population estimates of <it>C trachomatis </it>prevalence among young adults in Croatia, but it is challenging to obtain an adequate response rate. The prevalence of <it>C trachomatis </it>among young adults in Croatia found in this study was higher than that found in other European countries with similar survey response rates.</p

Home-based chlamydia testing of young people attending a music festival - who will pee and post?

<p>Abstract</p> <p>Background</p> <p>Chlamydia is most common among young people, but only a small proportion of Australian young people are tested annually. Home-based chlamydia testing has been piloted in several countries to increase testing rates, but uptake has been low. We aimed to identify predictors of uptake of home-based chlamydia testing to inform future testing programs.</p> <p>Methods</p> <p>We offered home-based chlamydia testing kits to participants in a sexual behaviour cross-sectional survey conducted at a music festival in Melbourne, Australia. Those who consented received a testing kit and were asked to return their urine or vaginal swab sample via post.</p> <p>Results</p> <p>Nine hundred and two sexually active music festival attendees aged 16-29 completed the survey; 313 (35%) opted to receive chlamydia testing kits, and 67 of 313 (21%) returned a specimen for testing. One participant was infected with chlamydia (1% prevalence). Independent predictors of consenting to receive a testing kit included older age, knowing that chlamydia can make women infertile, reporting more than three lifetime sexual partners and inconsistent condom use. Independent predictors of returning a sample to the laboratory included knowing that chlamydia can be asymptomatic, not having had an STI test in the past six months and not living with parents.</p> <p>Conclusions</p> <p>A low proportion of participants returned their chlamydia test, suggesting that this model is not ideal for reaching young people. Home-based chlamydia testing is most attractive to those who report engaging in sexual risk behaviours and are aware of the often asymptomatic nature and potential sequelae of chlamydia infection.</p

Diagnosis of genital Chlamydia trachomatis infections in asymptomatic males by testing urine by PCR.

An enzyme-linked immunosorbent assay (EIA) (MikroTrak; Syva) was compared with PCR (Amplicor; Roche) for detection of Chlamydia trachomatis in first-void urine (FVU) from 184 men attending a skin and venereal disease clinic. The prevalence of C. trachomatis in the population studied was 18.5%. Discrepant results between Syva EIA and Roche PCR were retested by using major outer membrane protein primer-based PCR. After retesting, the sensitivity, the specificity, and the positive and negative predictive values for the Syva EIA were 85.3, 100, 100, and 77.5%, respectively, and those for the Roche PCR 100, 100, 100, and 100%, respectively. It was concluded that PCR provides a highly sensitive and specific noninvasive screening method for genital chlamydial infection in asymptomatic men