Genetic Variation in the Complete MgPa Operon and Its Repetitive Chromosomal Elements in Clinical Strains of Mycoplasma genitalium

Mycoplasma genitalium has been increasingly recognized as an important microbe not only because of its significant association with human genital tract diseases but also because of its utility as a model for studying the minimum set of genes necessary to sustain life. Despite its small genome, 4.7% of the total genome sequence is devoted to making the MgPa adhesin operon and its nine chromosomal repetitive elements (termed MgPars). The MgPa operon, along with 9 MgPars, is believed to play an important role in pathogenesis of M. genitalium infection and has also served as the main target for development of diagnostic tools. However, genetic variation in the complete MgPa operon and MgPars among clinical strains of M. genitalium has not been addressed. In this study we examined the genetic variation in the complete MgPa operon (approximately 8.5 kb) and full or partial MgPar sequences (0.4–2.6 kb) in 15 geographically diverse strains of M. genitalium. Extensive variation was present in four repeat regions of the MgPa operon (with homology to MgPars) among and within strains while the non-repeat regions (without homology to MgPars) showed low-level variation among strains and no variation within strains. MgPars showed significant variation among strains but were highly homogeneous within strains, supporting gene conversion as the likely recombination mechanism. When applying our sequence data to evaluate published MgPa operon-based diagnostic PCR assays and genotyping systems, we found that 11 of 19 primers contain up to 19 variable nucleotides and that the target for one of two typing systems is located in a hypervariable repeat region, suggesting the likelihood of false results with some of these assays. This study not only provides new insights into the role of the MgPa operon in the pathogenesis of M. genitalium infection but has important implications for the development of diagnostic tools

Persistence of Mycoplasma genitalium Following Azithromycin Therapy

BACKGROUND: To determine clinical outcomes and cure rates for M.genitalium genital infection in men and women following azithromycin 1 g. METHODOLOGY: Patients attending Melbourne Sexual Health Centre between March 2005 and November 2007 with urethritis/epididymitis, cervicitis/pelvic inflammatory disease and sexual contacts of M.genitalium were tested for M.genitalium by polymerase chain reaction (PCR). M.genitalium-infection was treated with 1 g of azithromycin and a test-of-cure (toc) was performed one month post-azithromycin. Response to azithromycin, and response to moxifloxacin (400 mg daily for 10 days) in individuals with persistent infection post-azithromycin, was determined. PRINCIPAL FINDINGS: Of 1538 males and 313 females tested, 161 males (11%) and 30 females (10%) were infected with M.genitalium. A toc was available on 131 (69%) infected individuals (median = 36 days [range 12-373]). Of 120 individuals prescribed azithromycin only pre-toc, M.genitalium was eradicated in 101 (84%, 95% confidence intervals [CI]: 77-90%) and persisted in 19 (16%, 95% CI: 10-23%). Eleven individuals with persistent infection (9%, 95% CI: 5-15%) had no risk of reinfection from untreated-partners, while eight (7%, 95% CI: 3-12%) may have been at risk of reinfection from doxycycline-treated or untreated-partners. Moxifloxacin was effective in eradicating persistent infection in all cases not responding to azithromycin. Patients with persistent-M.genitalium were more likely to experience persistent symptoms (91%), compared to patients in whom M.genitalium was eradicated (17%), p<0.0001. CONCLUSION: Use of azithromycin 1 g in M.genitalium-infected patients was associated with unacceptable rates of persistent infection, which was eradicated with moxifloxacin. These findings highlight the importance of follow-up in M.genitalium-infected patients prescribed azithromycin, and the need to monitor for the development of resistance. Research to determine optimal first and second-line therapeutic agents for M.genitalium is needed

Frequency of Chlamydia trachomatis in Ureaplasma-positive healthy women attending their first prenatal visit in a community hospital in Sapporo, Japan

<p>Abstract</p> <p>Background</p> <p>Although <it>Chlamydia trachomatis </it>is the most commonly reported pathogen that causes urogenital infection such as urethritis or cervicitis, <it>Ureaplasma parvum </it>and <it>Ureaplasma urealyticum</it>, which are commensals in the genital tract, have also now been recognized as contributors to urogenital infection. However, whether the presence of either <it>U. parvum </it>or <it>U. urealyticum </it>is related to that of <it>C. trachomatis </it>in the urogenital tract remains unknown. We therefore attempted to estimate by PCR the prevalence of <it>C. trachomatis, U. parvum </it>and <it>U. urealyticum </it>in endocervical samples obtained from healthy women attending their first prenatal visit in Sapporo, Japan.</p> <p>Methods</p> <p>The samples were taken from 303 apparently healthy women, and the extracted DNAs (<it>n </it>= 280) were used for PCR detection targeting <it>C. trachomatis, U. parvum </it>and <it>U. urealyticum</it>. Statistical analysis of the data was performed by Fisher's exact test.</p> <p>Results</p> <p>PCR detection revealed that the prevalence of <it>C. trachomatis, U. parvum </it>and <it>U. urealyticum </it>was 14.3% (40/280), 41.7% (117/280) and 8.9% (25/280), respectively. <it>C. trachomatis ompA </it>genotype D was most frequently identified. Surprisingly, either <it>C. trachomatis </it>or <it>Ureaplasma </it>spp. was detected in almost half of the healthy women. Mixed infection of <it>C. trachomatis </it>with either <it>U. parvum </it>or <it>U. urealyticum </it>was also observed in 9.2% (26/280) of the women. There was a significant association between <it>C. trachomatis </it>and either <it>U. parvum </it>(<it>p </it>= 0.023) or <it>Ureaplasma </it>total (<it>p </it>= 0.013), but not <it>U. urealyticum </it>(<it>p </it>= 0.275).</p> <p>Conclusion</p> <p>This study demonstrated that the presence of <it>Ureaplasma </it>had a significant effect on the presence of <it>C. trachomatis </it>in the genital tract of healthy women, suggesting that mixed infection is an important factor in bacterial pathogenesis in the genital tract.</p

Iota-Carrageenan Is a Potent Inhibitor of Influenza A Virus Infection

The 2009 flu pandemic and the appearance of oseltamivir-resistant H1N1 influenza strains highlight the need for treatment alternatives. One such option is the creation of a protective physical barrier in the nasal cavity. In vitro tests demonstrated that iota-carrageenan is a potent inhibitor of influenza A virus infection, most importantly also of pandemic H1N1/2009 in vitro. Consequently, we tested a commercially available nasal spray containing iota-carrageenan in an influenza A mouse infection model. Treatment of mice infected with a lethal dose of influenza A PR8/34 H1N1 virus with iota-carrageenan starting up to 48 hours post infection resulted in a strong protection of mice similar to mice treated with oseltamivir. Since alternative treatment options for influenza are rare, we conclude that the nasal spray containing iota-carrageenan is an alternative to neuraminidase inhibitors and should be tested for prevention and treatment of influenza A in clinical trials in humans

Macroscopic order in a nematic liquid crystal: Perturbation by spontaneous director fluctuations

The dynamic alignment of the nematic director by near-orthogonal electric and magnetic fields has been investigated. The intermediate states during the relaxation process were found, with the aid of time-resolved deuterium NMR spectroscopy, to be markedly nonuniform. The macroscopic order was perturbed, although the initial and final states of the director appear to be essentially uniform. However, the initial state does have a profound influence on the uniformity of the director in the intermediate states. We have developed a fundamental model based on the effect of spontaneous director fluctuations to explain these unusual NMR observation

Enhanced expression of hepatocyte growth factor activator inhibitor type 2‐related small peptide at the invasive front of colon cancers

BACKGROUND: Hepatocyte growth factor activator inhibitor type 2‐related small peptide (H2RSP) is a small nuclear protein abundantly expressed in the gastrointestinal epithelium. However, its functions remain unknown. AIMS: To investigate the expression and localisation of H2RSP in normal, injured and neoplastic human intestinal tissue. METHODS: Immunohistochemical examination and in situ hybridisation for H2RSP were performed using normal and diseased intestinal specimens. Its subcellular localisation and effects on the cellular proliferation and invasiveness were examined using cultured cells. RESULTS: In the normal intestine, H2RSP was observed in the nuclei of surface epithelial cells and this nuclear localisation was impaired in regenerating epithelium. In vitro, the nuclear translocation of H2RSP was observed along with increasing cellular density, and an overexpression of H2RSP resulted in a reduced growth rate and enhanced invasiveness. H2RSP expression was down regulated in well‐differentiated colorectal adenocarcinomas. However, a marked up regulation of the cytoplasmic H2RSP immunoreactivity was observed in cancer cells at the invasive front. These cells showed low MIB‐1 labelling, an enhanced p16 expression and nuclear β‐catenin. The number of H2RSP‐positive cells in the invasive front of well‐differentiated adenocarcinomas was considerably higher in the cases with lymph node metastases than in node‐negative ones. CONCLUSION: In the normal intestine, the nuclear accumulation of H2RSP is a marker of differentiated epithelial cells. Although H2RSP was down regulated in colorectal adenocarcinomas, a paradoxical up regulation was observed in actively invading carcinoma cells. H2RSP immunoreactivity at the invasive front may serve as a marker of invasive phenotype of well‐differentiated colon cancers