Hiroshi Nakayama

High prevalence of Chlamydia trachomatis, Neisseria gonorrhoeae and Mycoplasma genitalium in female commercial sex workers in Japan

Our objectives were to explore the prevalence of Chlamydia trachomatis, Neisseria gonorrhoeae, and Mycoplasma genitalium in Japanese female commercial sex workers (CSWs), in comparison with pregnant women as controls. A high-risk group of 174 female CSWs and 90 asymptomatic pregnant women were enrolled in this study. Detection of C. trachomatis, N. gonorrhoeae, and M. genitalium on the endocervix of the women was performed mainly by using polymerase chain reaction (PCR)-based assays. The prevalence rates of C. trachomatis, N. gonorrhoeae, and M. genitalium were 19.0%, 32.8%, and 12.6%, respectively, in the CSWs, compared with 5.6%, 0%, and 1.1% respectively, in the pregnant women. These results suggest a high prevalence of C. trachomatis , N. gonorrhoeae, and M. genitalium in Japanese CSWs. We conclude that continued close monitoring of the prevalence of C. trachomatis, N. gonorrhoeae, and M. genitalium infection in CSWs is important for preventing the dissemination of these microorganisms, and that further investigation of M. genitalium as a sexually transmitted pathogen in women is needed.

Susceptibilities of Neisseria gonorrhoeae Isolates Containing Amino Acid Substitutions in GyrA, with or without Substitutions in ParC, to Newer Fluoroquinolones and Other Antibiotics

ABSTRACT We examined the antimicrobial susceptibilities of 85Neisseria gonorrhoeae isolates, classified according to the presence of amino acid substitutions in the GyrA and ParC proteins, to 12 fluoroquinolones and 7 other antibiotics. Sitafloxacin and HSR-903 showed excellent activity against N. gonorrhoeae, including strains with both GyrA and ParC substitutions. Among the strains with various GyrA substitutions, strains with a serine-91-to-phenylalanine mutation required the highest MICs of all of the fluoroquinolones tested and were cross-resistant to structurally unrelated β-lactams.

Antibiotic-resistant Phenotypes and Genotypes of neisseria gonorrhoeae Isolates in Japan: Identification of Strain Clusters With Multidrug-resistant Phenotypes

Objectives: To determine the antibiotic susceptibility and the genotype distributions of N. gonorrhoeae isolates in Fukuoka, Japan, and to evaluate the specific associations between genotypes and antibiotic resistance. Methods: Antibiotic susceptibility testing and N. gonorrhoeae multiantigen sequence typing (NG-MAST) were performed on 242 and 239 N. gonorrhoeae isolates, respectively, in Fukuoka, Japan in 2008. Results: No isolates showed resistance to spectinomycin, ceftriaxone, or cefixime, although 34 (14.0%) and 149 (61.6%) isolates displayed decreased susceptibility to ceftriaxone (minimum inhibitory concentration range, 0.06–0.5 mg/L) and cefixime (minimum inhibitory concentration range, 0.06–0.5 mg/L), respectively. Furthermore, 171 (70.7%), 68 (28.1%), 39 (16.1%), and 1 (0.4%) isolates were resistant to ciprofloxacin, tetracycline, penicillin, and azithromycin, respectively. The 239 isolates were divided by NG-MAST into 67 sequence types (STs); the 4 most common STs were ST2958 (20.5%), ST4018 (7.5%), ST1407 (6.7%), and ST4487 (5.9%). ST2958 and ST1407 were characterized by a multidrug-resistant phenotype, whereas ST4018 and ST4487 presented a susceptible phenotype. Interestingly, ST1407, which is now common in Europe and Australia, was identified as a predominant ST in this study. Conclusions: This is the first report combining N. gonorrhoeae antibiotic susceptibility testing with molecular typing by using NG-MAST in Japan. Although a large diversity in NG-MAST was identified, based on comparisons with the international data, the ST1407 with a multidrug-resistant phenotype currently seems to be circulating worldwide.

Analysis of quinolone resistance mechanisms in a sparfloxacin-resistant clinical isolate of Neisseria gonorrhoeae

Background and Objectives: Recently, a reduction in the susceptibility of clinical isolates of Neisseria gonorrhoeae to newer fluoroquinolones including sparfloxacin in vitro has been recognized in Japan. The quinolone resistance mechanisms in gonococcal isolates from a patient with clinical failure of sparfloxacin treatment was investigated. Goal: To report a man with gonococcal urethritis in whom clinical failure of sparfloxacin treatment occurred and to examine the quinolone resistance mechanisms in gonococcal isolates from the patient. Study Design: A man with gonococcal urethritis was treated with oral 100 mg sparfloxacin three times daily for 5 days. However, clinical failure of the sparfloxacin treatment was observed. The antimicrobial susceptibilities of pretreatment and posttreatment isolates to sparfloxacin and other agents were measured. To analyze quinolone resistance mechanisms in the set of isolates, DNA sequencing of the genes corresponding to the quinolone resistance‐determining regions within the GyrA and ParC proteins was performed. We also assayed the intracellular sparfloxacin accumulation level in these gonococcal cells. Moreover, we performed pulsed‐field gel electrophoresis analysis to determine whether the pretreatment and posttreatment isolates were isogenic. Results: The minimum inhibitory concentration of sparfloxacin for the posttreatment isolate (4 μg/ml) was 16 times higher than that for the pretreatment isolate (0.25 μg/ml). The pretreatment isolate contained three mutations, including a Ser‐91 to Phe mutation and an Asp‐95 to Asn mutation in GyrA and a Ser‐88 to Pro mutation in ParC. The posttreatment isolate had four mutations, including the same three mutations and an additional Glu‐91 to Gly mutation in ParC. The sparfloxacin accumulation level within 30 minutes in the posttreatment isolate was four times less than that in the pretreatment isolate. There were no differences in the pulsed‐field gel electrophoresis patterns between the pretreatment and posttreatment isolates from the patient. Conclusions: The emergence of a fluoroquinolone‐resistant N. gonorrhoeae isolate with multiple mutations involving GyrA and ParC reduced the response to sparfloxacin treatment. Multiple dosing and long‐term treatment with sparfloxacin seems to induce a mutation in ParC and an alteration leading to reduced drug accumulation that contribute to increasing the fluoroquinolone resistance level.

Evaluation of a new amplified enzyme immunoassay (EIA) for the detection of Chlamydia trachomatis in male urine, female endocervical swab, and patient obtained vaginal swab specimens.

Aims—To compare the performance of a new generation dual amplified enzyme immunoassay (EIA) with a molecular method for the diagnosis of Chlamydia trachomatis, using a range of urogenital samples, and to assess the reliability of testing self collected vaginal specimens compared with clinician collected vaginal specimens. Methods—Two population groups were tested. For the first population group, first void urine samples were collected from 193 male patients with urethritis, and endocervical swabs were collected from 187 high risk commercial sex workers. All urine and endocervical specimens were tested by a conventional assay (IDEIA chlamydia), a new generation amplified immunoassay (IDEIA PCE chlamydia), and the Amplicor polymerase chain reaction (PCR). Discrepant results obtained among the three sample types were confirmed using a nested PCR test with a different plasmid target region. For the second population group, four swab specimens, including one patient obtained vaginal swab, two clinician obtained endocervical swabs, and one clinician obtained vaginal swab, were collected from 91 high risk sex workers. Self collected and clinician collected vaginal swabs were tested by IDEIA PCE chlamydia. Clinician obtained endocervical swabs were assayed by IDEIA PCE chlamydia and Amplicor PCR. Results—The performance of the IDEIA PCE chlamydia test was comparable to that of the Amplicor PCR test when male urine and female endocervical swab specimens were analysed. The relative sensitivities of IDEIA, IDEIA PCE, and Amplicor PCR on male first void urine specimens were 79.3%, 91.4%, and 100%, respectively. The relative sensitivities of the three tests on female endocervical specimens were 85.0%, 95.0%, and 100%, respectively. The positivity rates for patient collected vaginal specimens and clinician collected vaginal specimens by IDEIA PCE were 25.2% and 23.1%, respectively, whereas those for clinician collected endocervical swabs by PCR and IDEIA PCE were both 27.5%. Conclusions—IDEIA PCE chlamydia is a lower cost but sensitive alternative test to PCR for testing male urine samples and female endocervical swabs. In addition, self collected or clinician collected vaginal specimens tested by IDEIA PCE chlamydia are a reliable alternative to analysing endocervical specimens.

Reduced Chlamydial Infection and Gonorrhea among Commercial Sex Workers in Fukuoka City, Japan

Background: Until recently, epidemiologic studies of sexually transmitted diseases (STDs), including human immunodeficiency virus type‐1 (HIV‐1) infection, amongjapanese female commercial sex workers and their patterns of condom use have been rare. We investigated trends in STDs among female commercial sex workers and their condom use patterns in Fukuoka, Japan, from 1990 through 1995.

Detection of Chlamydia trachomatis in urine by polymerase chain reaction: Preliminary results

Abstract Detection of Chlamydia trachomatis in specimens of urine from men with acute urethritis by means of a rapid and convenient polymerase chain reaction (PCR)-based kit is reported. Results of the PCR were compared with those obtained by an enzyme immunoassay (EIA). Of 52 first-voided urine specimens, 22 (42.3%) were positive for C trachomatis , as determined by both PCR and EIA; 4 (7.7%) were positive by PCR and negative by EIA, and only 1 (1.9%) was negative by PCR and positive by EIA. The remaining 25 (48.1%) were negative by both PCR and EIA. These findings suggest that PCR assay is suitable for detection of C trachomatis in urine and may be more sensitive than EIA. Further studies are indicated.