Akiko Kanayama

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.

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.

High Prevalence of Azithromycin-Resistant Neisseria gonorrhoeae Isolates With a Multidrug Resistance Phenotype in Fukuoka, Japan.

Background The current guidelines recommend a combination of ceftriaxone and azithromycin as a first-line treatment of gonorrhea in the United States and Europe. Despite not being recommended as a first-line regimen in Japan, an oral 2-g dose of azithromycin did become available for gonococcal infections in 2009. Recently, the emergence of azithromycin-resistant Neisseria gonorrhoeae isolates has been reported in several countries, including Japan. Methods Antimicrobial susceptibility testing was performed on a total of 677 clinical isolates of N. gonorrhoeae obtained from January 2010 to December 2013 in Fukuoka, Japan. A molecular analysis by N. gonorrhoeae multiantigen sequence typing was conducted on the azithromycin-resistant isolates. Results The proportion of azithromycin-resistant isolates (minimum inhibitory concentration > 0.5 &mgr;g/mL) increased significantly from 1.8% in 2010 to 22.6% in 2013 (P < 0.001). Among 50 azithromycin-resistant isolates, 30 (60%) exhibited a resistant phenotype to multiple drugs including cefixime. The 2 predominant sequence types (STs) identified by N. gonorrhoeae multiantigen sequence typing were ST6798 (por allele 4033 and tbpB allele 110) and ST1407 (por allele 908 and tbpB allele 110) at 40.0% (20/50) and 12.0% (6/50), respectively. There was a statistically significant increase of the proportion of ST6798 from 0% (0/19) in 2010–2012 to 64.5% (20/31) in 2013 (P < 0.001). Conclusions Over the previous 4 years, an increasing prevalence of azithromycin-resistant N. gonorrhoeae isolates with a multidrug-resistant phenotype was observed. Furthermore, the azithromycin-resistant isolates seemed to belong to 2 predominant STs. As a result, continued surveillance of gonococci resistant to antimicrobial agents, including azithromycin in Fukuoka, Japan, is necessary.

Antimicrobial activity of gemifloxacin (SB-265805), a newer fluoroquinolone, against clinical isolates of Neisseria gonorrhoeae, including fluoroquinolone-resistant isolates

Antimicrobial activity of gemifloxacin (SB-265805), a newly developed fluoroquinolone, to Japanese isolates of Neisseria gonorrhoeae was compared with those of various fluoroquinolones, including norfloxacin, ciprofloxacin, tosufloxacin, levofloxacin, sparfloxacin, and trovafloxacin. Among the fluoroquinolones tested, gemifloxacin was most active against N. gonorrhoeae isolates. The MIC90 values of gemifloxacin for 94 N. gonorrhoeae isolated from 1992 through 1993 and 100 isolated from 1996 through 1997 were 0.03 and 0.125 microg/ml, respectively. On the other hand, MIC90 values of the other fluoroquinolone for the 1992-1993 isolates and the 1996-1997 isolates ranged from 0.125 to 2 microg/ml and from 0.5 to 8 microg/ml, respectively. Gemifloxacin was also the most potent fluoroquinolone against 31 ciprofloxacin-resistant isolates with the ciprofloxacin MIC of 1 to 16 microg/ml, for which the gemifloxacin MIC50 and MIC90 values were 0.25 and 2 microg/ml, respectively. Moreover, the activity of gemifloxacin against fluoroquinolone-resistant gonococcal isolates containing multiple amino acid substitutions in both GyrA and ParC proteins was superior to those of the other compounds.