Identification of treatment strategies for Mycoplasma genitalium-related urethritis in male patients by culturing and antimicrobial susceptibility testing

Mycoplasma genitalium was first isolated from urethral swab specimens of male patients with non-gonococcal urethritis. However, the isolation of M. genitalium strains from clinical specimens has been difficult. Co-cultivation with Vero cells is one available technique for the isolation of M. genitalium. The strains that can be used for antimicrobial susceptibility testing by broth dilution or agar dilution methods are limited. Macrolides, such as azithromycin (AZM), have the strongest activity against M. genitalium. However, AZM-resistant strains have emerged and spread. Mutations in the 23S rRNA gene contribute to the organism's macrolide resistance, which is similar to the effects of the mutations in macrolide-resistant Mycoplasma pneumoniae. Of the fluoroquinolones, moxifloxacin (MFLX) and sitafloxacin have the strongest activities against M. genitalium, while levofloxacin and ciprofloxacin are not as effective. Some clinical trials on the treatment of M. genitalium-related urethritis are available in the literature. A doxycycline regimen was microbiologically inferior to an AZM regimen. For cases of treatment failure with AZM regimens, MFLX regimens were effective.

Variability of trinucleotide tandem repeats in the MgPa operon and its repetitive chromosomal elements in Mycoplasma genitalium

Mycoplasma genitalium, a human pathogen associated with sexually transmitted diseases, is unique in that it has the smallest genome of any known free-living organism. Despite its small genome, 4.7 % of the total genomic sequence is devoted to making the MgPa adhesin operon (containing the MG190, MG191 and MG192 genes) and its repetitive chromosomal sequences (known as MgPars). The goals of this study were to investigate the location, organization and variability of trinucleotide tandem repeats (TTRs) in the MgPa operon and MgPars and to explore the possible mechanisms and role of TTR variations. By analysing the complete MgPa operon and complete or partial MgPar sequences in a collection of 15 geographically diverse clinical strains of M. genitalium, TTR sequences were identified in four regions in MG191, one region in MG192, and two or three regions in each of all nine MgPars except for MgPar 3. These TTRs were variable not only in the repeat copy number but also in the repeat unit sequence among or within strains. The key mechanisms for the TTR variations likely include recombination between MgPa and MgPars, and slipped-strand mispairing. TTR variation may represent a mechanism to maximize the variation of the MgPa operon, which is complementary to genetic variation involving segmental recombination between MgPa and MgPars, thus enhancing the organism's ability to adhere to and colonize host cells as well as evasion of the host immune system.

Effect of gatifloxacin against Mycoplasma genitalium-related urethritis: an open clinical trial

Objectives

Mycoplasma genitalium and Chlamydia trachomatis are the primary pathogens detected from non-gonococcal urethritis (NGU). In this study, the efficacy of gatifloxacin was examined against M genitalium-related urethritis.

Methods

The study was an open clinical trial evaluating the effectiveness of gatifloxacin with 200 mg doses twice a day for 7 days against male NGU.

Results

Between March and September 2008, 169 male patients were enrolled, and microbiological and clinical cure rates could be evaluated in 86 patients detected with C trachomatis or M genitalium and in 135 with NGU, respectively. Microbiological cure rates of gatifloxacin against C trachomatis and M genitalium were 100% and 83%, respectively, and the total clinical cure rate was 99%.

Conclusion

Analysis of in-vivo and in-vitro data from the literature of fluoroquinolone efficacies against M genitalium suggests that a MIC90 of 0.125 μg/ml or less may be useful for optimal activity against M genitalium infection.

[Usefulness of real-time PCR in detecting Chlamydia trachomatis and Neisseria gonorrhoeae in endocervical swabs and first-voided urine specimens]

We evaluated performance of Abbott RealTime CT/NG assay (real-time PCR, Abbott Japan) for detect Chlamydia trachomatis and Neisseria gonorrhoeae by real-time PCR in 88 female patients with cervicitis symptoms seen at gynecological clinics and 100 male patients with urethritis symptoms seen at urological or dermatology clinics in Kitakyushu, Japan. Endocervical swab and first-voided urine (FVU) specimens were then collected from women and FVU specimens from men. Detection rates of C. trachomatis and N. gonorrhoeae by real-time PCR in the 3 types of specimens were compared to those by ProbeTec ET assay (ProbeTec, BD Diagnostic System). The overall positive concordance between real-time PCR and ProbTec were 97.1% (66/68) for C. trachomatis and 100% (33/33) for N. gonorrhoeae, C. trachomatis detection yielded 3 discordant results in endocervical specimens and 1 discordant result in male FVU by real-time PCR and ProbTec. Three of 4 reexamined using Aptime Combo 2 Assay (Fuji Rebio Inc.) were positive for C. trachomatis. Endocervical swab and FVU specimen results for C. trachomatis were discordant in 3 cases in real-time PCR and 4 in ProbeTec. Subjects with 2 or more positive endocervical awab results in female or male FVU specimens were assumed to be "true positive" for C. trachomatis. The sensitivities of real-time PCR for detecting C. trachomatis was 94.4% in endocervical swabs, 77.8% in female FVU and 97.4% in the male FVU. The sensitivities for real-time PCR for detecting N. gonorrhoeae was 100% in all 3 specimentypes. Abbott RealTime CT/NG assay was useful for detecting C. trachomatis using endocervical swabs or male FVU specimens and for detecting N. gonorrhoeae using endocervical swabs and all FVU specimens.

The nationwide study of bacterial pathogens associated with urinary tract infections conducted by the Japanese Society of Chemotherapy

This study was conducted by the Japanese Society of Chemotherapy and is the first nationwide study on bacterial pathogens isolated from patients with urinary tract infections at 28 hospitals throughout Japan between January 2008 and June 2008. A total of 688 bacterial strains were isolated from adult patients with urinary tract infections. The strains investigated in this study are as follows: Enterococcus faecalis (n = 140), Escherichia coli (n = 255), Klebsiella pneumoniae (n = 93), Proteus mirabilis (n = 42), Serratia marcescens (n = 44), and Pseudomonas aeruginosa (n = 114). The minimum inhibitory concentrations of 39 antibacterial agents used for these strains were determined according to the Clinical and Laboratory Standards Institute (CLSI) manual. All Enterococcus faecalis strains were susceptible to ampicillin and vancomycin. Although a majority of the E. faecalis strains were susceptible to linezolid, 11 strains (7.8%) were found to be intermediately resistant. The proportions of fluoroquinolone-resistant Enterococcus faecalis, Escherichia coli, Proteus mirabilis, and S. marcescens strains were 35.7%, 29.3%, 18.3%, and 15.2%, respectively. The proportions of E. coli, P. mirabilis, K. pneumoniae, and S. marcescens strains producing extended-spectrum β-lactamase were 5.1%, 11.9%, 0%, and 0%, respectively. The proportions of Pseudomonas aeruginosa strains resistant to carbapenems, aminoglycosides, and fluoroquinolones were 9.2%, 4.4%, and 34.8%, respectively, and among them, 2 strains (1.8%) were found to be multidrug resistant. These data present important information for the proper treatment of urinary tract infections and will serve as a useful reference for periodic surveillance studies in the future.

Population-based study of asymptomatic infection with Chlamydia trachomatis among female and male students

There are few epidemiological studies of asymptomatic chlamydial infection among students in non-medical settings with minimal bias and improved accuracy; thus, useful data from screening among students are limited. We aimed to obtain accurate epidemiological information about asymptomatic chlamydial infection among students in non-medical settings. A population-based cross-sectional survey of 10,440 >or=18-year-old asymptomatic students who volunteered for a urine screening test for chlamydia was conducted. The prevalences of asymptomatic infection were 9.5% for women and 6.7% for men. Multivariate analysis revealed the risk factors to be a lifetime history of >or=4 sexual partners for women (odds ratio [OR] 3.17) and inconsistent condom use for men (OR 4.18). For both sexes, younger age at first intercourse was associated with a higher rate of inconsistent condom use. This study produced accurate epidemiological information on asymptomatic chlamydial infection. These results may contribute to the establishment of preventive countermeasures against such infection.

Prevalence of Mycoplasma genitalium among female students in vocational schools in Japan

OBJECTIVE

In Japan it was reported that about 9% of sexually active female teenagers had Chlamydia trachomatis. Most of them were asymptomatic, which may lead to continuing spread of the infection. Like C trachomatis, Mycoplasma genitalium is a pathogen in male non-gonococcal urethritis. However, few studies of the prevalence of M genitalium in the general population have been reported. The objective of this study was to determine the prevalence of M genitalium infection among younger females and to determine risk factors for this infection.

METHODS

The study was conducted between October 2005 and January 2006 using first voided urine specimens and questionnaires from female students of three vocational schools in the Miyazaki prefecture, Japan. C trachomatis was detected with Amplicor PCR. M genitalium was detected with inhibitor controlled real-time TaqMan PCR detecting the MgPa adhesion gene and with a PCR detecting the 16S rRNA. Risk factors associated with infection of M genitalium or C trachomatis were analysed with Fisher's exact test.

RESULTS

Among 298 female, 249 (84%) had had experience of sexual intercourse. The prevalence of M genitalium was 2.8% (95% CI 0.76% to 4.86%) and the prevalence of C trachomatis was 8.8% (95% CI 5.31% to 12.36%).

CONCLUSIONS

The risk factors of infection with M genitalium were more than five lifetime sexual partners and co-infection with C trachomatis.

Usefulness of oral wash specimens for detecting Chlamydia trachomatis from high-risk groups in Japan

Orogenital sex is recognized as a route for the transmission of Chlamydia trachomatis (CT) which thus causes male chlamydial urethritis. Patients with a pharyngeal CT infection have no gross lesions, but CT was tested by pharyngeal swabs. In this study, the usefulness of oral wash specimens for detecting CT was compared to that of swab specimens. In addition, oral wash specimens were also used to screen for CT pharyngeal infection. Eighteen female commercial sex workers in whom CT was detected from pharyngeal swabs were re-examined using both methods. The positive rate for CT was 44% by swabs and 61% by oral wash specimens. Forty-eight male students with CT-positive urine were also screened for pharyngeal CT infection. The positive rates were 6% by swabs and 10% by oral wash specimens. Our findings therefore indicate that oral wash specimens more effectively detected pharyngeal CT infection than pharyngeal swabs.

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 beta-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.

Isolation of Mycoplasma genitalium from first-void urine specimens by coculture with Vero cells

Isolation of Mycoplasma genitalium from clinical specimens remains difficult. We describe an improvement of the Vero cell coculture method in which the growth of M. genitalium was monitored by quantitative real-time PCR. Four new M. genitalium strains were isolated from six first-void urine specimens of male Japanese patients with urethritis. In two of them, only M. genitalium was detected: one also contained Ureaplasma urealyticum, and one contained Chlamydia trachomatis, Neisseria gonorrhoeae, U. urealyticum, and Ureaplasma parvum. In the specimens yielding isolates of M. genitalium, growth was documented by quantitative PCR after two to five passages in Vero cells. The complete isolation procedure from the initial inoculation to completion of single-colony cloning took about 1 year. Isolation of M. genitalium from urine specimens proved to be more difficult than from swab specimens. Due to the cytotoxic effect of urine, a procedure involving washing of the urinary sediment was introduced. Furthermore, prolonged storage of the urine specimens before culture was shown to be detrimental to the success of isolation, as shown by the lack of success in attempts to isolate M. genitalium from mailed urine specimens as well as by simulation experiments. High concentrations of penicillin G and amphotericin B were surprisingly inhibitory to the growth of wild-type M. genitalium strains, but penicillin G at 200 IU/ml and polymyxin B at 500 microg/ml could be used as selective antibiotics to avoid bacterial overgrowth in the Vero cell cultures.

Antibiotic susceptibility testing of Mycoplasma genitalium by TaqMan 5' nuclease real-time PCR

Mycoplasma genitalium is an important pathogen in male nongonococcal urethritis (NGU). Isolation of M. genitalium from clinical specimens by axenic culture is very difficult and time-consuming, and very few strains are available for antibiotic susceptibility testing. Primary isolation of M. genitalium by coculture with Vero cells improves the isolation rate significantly. However, some strains cannot be adapted to axenic culture. In this study, we determined the antibiotic susceptibility of M. genitalium strains grown in Vero cell culture with dilutions of antibiotics. Growth of M. genitalium was monitored by a quantitative PCR assay detecting a single-copy region of the mgpB adhesin gene. Growth inhibition in the presence of antibiotics was expressed as a percentage of the DNA load of controls grown in the absence of antibiotics. Eighteen strains were examined, including 6 new strains isolated from urethral swab specimens and 4 new strains isolated from urine specimens collected from Japanese men. Eight strains adapted to axenic culture were also tested by the conventional broth dilution method. The two methods had an acceptable correlation. Azithromycin was the most active drug against M. genitalium. Among the fluoroquinolones, moxifloxacin had the highest activity, with MICs ranging from 0.03 to 0.5 mg/liter, whereas ciprofloxacin and levofloxacin were considerably less active, with MICs ranging from 0.5 to 16 mg/liter and 0.25 to 4 mg/liter, respectively. MICs for tetracycline ranged from 0.125 to 4 mg/liter. This new method could increase the number of M. genitalium strains available for antibiotic susceptibility testing and significantly shorten the time from sampling to MIC results.