Surveillance of the prevalence of macrolide and/or fluoroquinolone resistance-associated mutations in Mycoplasma genitalium in Japan.

To clarify the status of macrolide and fluoroquinolone resistance of clinical strains of Mycoplasma genitalium in Japan, we amplified portions of the gyrA, parC, and 23S rRNA genes from DNAs in 627 first-voided urine specimens collected from men with M. genitalium-positive urethritis who visited clinics mainly in Sendai, Tokyo, and Osaka, Japan, from 2013 to 2017, by PCR and sequenced. The incidence of single amino acid changes at Met95 or Asp99 in GyrA increased chronologically and was approximately 10% from 2015 onward. The incidence of amino acid changes at Ser83 or Asp87 in ParC was approximately 50% in 2013 but increased to 60-70% from 2014 to 2017. The incidence of mutations at A2071 or A2072 in the 23S rRNA gene increased chronologically and reached over 70% in 2017. The prevalence of M. genitalium harboring alterations in ParC and mutations in the 23S rRNA gene increased and was approximately 50% in 2016 and 2017. The prevalence of M. genitalium with alterations in both GyrA and ParC and mutations in the 23S rRNA gene, which could be associated with treatment failures with the sitafloxacin and azithromycin regimens, were approximately 15% and 10% in 2016 and 2017, respectively. The prevalence of M. genitalium with genetic alterations associated with resistance to fluoroquinolones and/or macrolides is increasing rapidly in Japan. We must prevent the further selection of multi-drug-resistant M. genitalium so that M. genitalium infections will not become untreatable.

Examination of the correlation between the manual and automated serological testing methods for syphilis.

We evaluated the correlation between the conventional manual serological testing method for syphilis and a novel automated serological testing method and between six different reagents used in the automated method. Twenty-six serum samples, which were positive on non-treponemal manual serological testing, were obtained from 19 patients with early syphilis. The samples were manually analyzed using the non-treponemal serological test for syphilis kit and automatically analyzed using six different reagents approved by the Ministry of Health, Labor and Welfare in Japan. Statistically significant correlations were observed between most of the reagents used in the automated testing (r = 0.652-0.996, P < 0.001), except for one combination of the reagents. In the simple regression analysis, the slope of the simple regression line (range, 0.014-3.040) and some of the regression coefficients were not equal to 1.0. Therefore, it is recommended that when the automated serological testing method is used to test for syphilis, the same reagent should be consistently selected to evaluate the changes in antibody titers. Statistically significant correlations were also observed between the manual method and all the reagents used in the automated method (r = 0.682-0.811, P < 0.001). In this case, the regression coefficients ranged 0.375-6.270, and the simple regression line intercept ranged -71.926 to 4.184. The regression coefficient and the intercept between the manual method and some of the reagents used in the automated method were not similar to the values described in the documentation attached to the reagents used in this study.