40 research outputs found

    MLVA Subtyping of Genovar E Chlamydia trachomatis Individualizes the Swedish Variant and Anorectal Isolates from Men who Have Sex with Men

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    This study describes a new multilocus variable number tandem-repeat (VNTR) analysis (MLVA) typing system for the discrimination of Chlamydia trachomatis genovar D to K isolates or specimens. We focused our MLVA scheme on genovar E which predominates in most populations worldwide. This system does not require culture and therefore can be performed directly on DNA extracted from positive clinical specimens. Our method was based on GeneScan analysis of five VNTR loci labelled with fluorescent dyes by multiplex PCR and capillary electrophoresis. This MLVA, called MLVA-5, was applied to a collection of 220 genovar E and 94 non-E genovar C. trachomatis isolates and specimens obtained from 251 patients and resulted in 38 MLVA-5 types. The genetic stability of the MLVA-5 scheme was assessed for results obtained both in vitro by serial passage culturing and in vivo using concomitant and sequential isolates and specimens. All anorectal genovar E isolates from men who have sex with men exhibited the same MLVA-5 type, suggesting clonal spread. In the same way, we confirmed the clonal origin of the Swedish new variant of C. trachomatis. The MLVA-5 assay was compared to three other molecular typing methods, ompA gene sequencing, multilocus sequence typing (MLST) and a previous MLVA method called MLVA-3, on 43 genovar E isolates. The discriminatory index was 0.913 for MLVA-5, 0.860 for MLST and 0.622 for MLVA-3. Among all of these genotyping methods, MLVA-5 displayed the highest discriminatory power and does not require a time-consuming sequencing step. The results indicate that MLVA-5 enables high-resolution molecular epidemiological characterisation of C. trachomatis genovars D to K infections directly from specimens

    Active Trachoma and Ocular Chlamydia trachomatis Infection in Two Gambian Regions: On Course for Elimination by 2020?

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    Trachoma is the leading infectious cause of blindness worldwide, and is mainly found in tropical and poor countries. It is caused by infection of the eyes with the bacterium Chlamydia trachomatis. However, sometimes the clinical signs of disease can be present without infection being detected. Control efforts involve surgery, antibiotic treatment, face washing, and environmental improvement for better hygiene. Surveys of trachoma help countries to know whether and where they should implement control interventions. The Gambia is found in West Africa and has suffered from trachoma for decades. We conducted a survey of two Gambian regions to look at how much trachoma disease and C. trachomatis infection there is in the eyes. We found that although there was enough disease (≥10%) to warrant antibiotic treatment for everyone in the regions, there was nearly no infection (0.3%). This means that using clinical signs alone to make treatment decisions in low prevalence settings like The Gambia can lead to the waste of scarce resources. Our results also suggest that since less than 1% of children are infected with C. trachomatis, The Gambia is on course to achieve the World Health Organization's aim of eliminating blinding trachoma by the year 2020

    Mycoplasma genitalium: An Emerging Cause of Sexually Transmitted Disease in Women

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

    Mechanisms of action of systemic antibiotics used in periodontal treatment and mechanisms of bacterial resistance to these drugs

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    2019 European guideline on the management of lymphogranuloma venereum

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    New or important issues in this updated version of the 2013 European guideline on the management of lymphogranuloma venereum (LGV): EPIDEMIOLOGY: Lymphogranuloma venereum continues to be endemic among European men who have sex with men (MSM) since 2003. Lymphogranuloma venereum infections in heterosexuals are extremely rare in Europe, and there is no evidence of transmission of LGV in the European heterosexual population. AETIOLOGY AND TRANSMISSION: Chlamydia trachomatis serovars/genovars L2b and L2 are the causative strains in the majority of cases in Europe. CLINICAL FEATURES: Among MSM, about 25% of the anorectal LGV infections are asymptomatic. Genital infections among MSM are rare; the ratio of genital vs. anorectal LGV infections is 1 in 15. DIAGNOSIS: To diagnose LGV, a sample tested C. trachomatis positive with a commercial nucleic acid amplification test (NAAT) platform should be confirmed with an LGV discriminatory NAAT. TREATMENT: Doxycycline 100 mg twice a day orally for 21 days is the recommended treatment for LGV. This same treatment is recommended also in asymptomatic patients and contacts of LGV patients. If another regimen is used, a test of cure (TOC) must be performed

    Development of a Genomics-Based PCR Assay for Detection of Mycoplasma pneumoniae in a Large Outbreak in New York State

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    A genomics-based PCR method was developed and used to test specimens from patients involved in a large outbreak of Mycoplasma pneumoniae in a closed religious community in New York State. New P1 adhesin gene primers were designed to bind to 9 of 10 target sequences in the repetitive-element sequences obtained from the whole genome sequence of M. pneumoniae. This PCR method had a sensitivity of 0.006 CFU and a specificity of 100% for M. pneumoniae. The PCR was validated by testing a subset of patient samples by culture and comparing the results to those obtained by PCR. Of the initial 280 samples tested, 73 were positive by PCR and 22 were positive by culture. All samples positive by culture were also positive by PCR. Follow-up testing of selected patients 3 to 6 weeks after antibiotic treatment revealed that eight samples remained positive by PCR and that three samples remained positive by culture. Additionally, no nonspecific PCR inhibition was detected as a result of the specimen type, transport medium, or sample preparation methodology. The study demonstrates that the PCR described here is a rapid, sensitive, and specific method for the identification of M. pneumoniae and was helpful for the detection and monitoring of the outbreak
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