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BackgroundNeisseria gonorrhoeaegenotyping by whole-genome sequencing (WGS) is expensive for a large sample set, a less expensive and more efficient genotyping method is required. We developed a high-throughput genotyping method forN. gonorrhoeaeto improve molecular epidemiological typing and antimicrobial-resistant identification inN. gonorrhoeaeantimicrobial susceptibility surveillance.MethodsWe used multiplex-tailed PCR to amplify and sequence 15 alleles from multilocus sequence typing (MLST),N. gonorrhoeaemultiantigen sequence typing (NG-MAST), andN. gonorrhoeaesequence typing for antimicrobial resistance (NG-STAR). After indexing-PCR, we sequenced the DNA library using the MiSeq platform (Illumina). Sequencing reads werede novoassembly or constructing consensus sequences of alleles, then assigned sequence type. We used 54 previously characterized strains ofN. gonorrhoeaeand WGS data to validate our method.ResultsThe allele identification results of MLST and NG-STAR in all strains agreed with the draft WGS. However, in NG-MAST, only 35 strains agreed. Disagreement was found in the NG-MAST ofporBin 15 strains and oftbpBin seven strains. QRDR analysis perfectly predicted levofloxacin resistance. But was less successful in predicting reduced susceptibility or resistance phenotype to penicillin G, cefixime, or ceftriaxone usingpenA, porB, ponA, ormtrRalleles.ConclusionsThe successful performance in MLST and NG-STAR of our method was validated in this study. This method may be useful for large-scale genotyping forN. gonorrhoeaesurveillance in a cost- and labor-saving manner. Phenotypic prediction of antimicrobial susceptibility by combining multiple alleles may be necessary for other than fluoroquinolones.

While invasive meningococcal disease (IMD) is a major public concern worldwide, IMD is categorized as a rare infectious disease in Japan and, thus, its causative agents and epidemiology have not yet been characterized in detail. In the present study, we used molecular methods to epidemiologically characterize 291 meningococcal strains isolated in Japan over a 17-year period between 2003 and 2020 by whole genome sequencing (WGS). Serogroup Y meningococci (MenY) were the most abundant, followed by B (MenB) and then C and W among meningococci from IMD patients, while non-groupable as well as MenY and MenB were the most abundant among isolates from healthy carriers. Sequence type (ST) defined by multilocus sequence typing (MLST) showed that ST-1655 and ST-23 belonging to clonal complex (cc) 23 were dominant among Japanese IMD isolates, while ST-11026 (cc32) unique to Japan as well as ST-23 were dominant among Japanese non-IMD isolates. Phylogenetic analyses of ST by MLST revealed that Japanese isolates were classified with 12 ccs, including recently reported cc2057. Phylogenic analyses by WGS showed that isolates of ST-11026 and of ST-1655 were genetically close, whereas ST-23 isolates appeared to be diverse. Moreover, comparisons with other cc11 isolates isolated worldwide indicated that some Japanese cc11 isolates were genetically close to those isolated in Europe and China. An in silico analysis suggested that 14.3 and 44.2% of Japanese MenB were cross-reactive with 4CMenB and rLP2086 MenB vaccines, respectively. The results in the present study revealed that some epidemiological features were unique to Japan.

Objectives To investigate the spread of ceftriaxone-resistant Neisseria gonorrhoeae lineages similar to strains H041 (2009) and FC428 (2015), we characterized 55 strains collected in 2013 from hospitals across Japan. Methods Susceptibility testing and whole-genome sequencing. Results Susceptibility rates were 58% for cefixime and 98% for ceftriaxone. The 55 strains were whole-genome sequenced and classified into nine MLST-STs. MLST-ST1901 was the most prevalent (n = 19) followed by MLST-ST7363 (n = 12) and MLST-ST7359 (n = 11). The most prevalent penA [encoding penicillin binding protein 2 (PBP2)] mosaic types, based on the N. gonorrhoeae sequence typing for antimicrobial resistance (NG-STAR) scheme, were 10.001 (n = 20) followed by 34.001 (n = 13). The H041 and FC428 strains were not detected; however, a single ceftriaxone-resistant strain (TUM15748) with a MIC of 0.5 mg/L ceftriaxone was identified. The TUM15748 strain belonged to MLST-ST7359 and N. gonorrhoeae multiantigen sequence typing-ST6771, and had a novel PBP2 (PBP2TUM15748, penA type 169.001). The amino acid sequence of PBP2TUM15748 showed partial similarity to that of PBP2 from N. gonorrhoeae GU140106 and commensal Neisseria perflava and Neisseria cinerea. Natural transformation and recombination experiments using full-length TUM15748 penA showed that the ceftriaxone MICs of transformants increased 16-fold or more compared with the parental ceftriaxone-susceptible recipient strain (NG9807, belonging to MLST-ST7363). No ceftriaxone-resistant MLST-ST7359 strains have previously been reported. Conclusions We showed here that a ceftriaxone-susceptible lineage acquired a mutant PBP2 mosaic type, integrating partial PBP2 sequences from commensal Neisseria species, resulting in the emergence of ceftriaxone-resistant strains.

Introduction. Only approximately 40 cases of invasive meningococcal diseases are reported annually in Japan, and the dominant strains are serogroup Y meningococci (MenY) followed by serogroup B meningococci (MenB). Within the last 10 years, Neisseria meningitidis strains belonging to clonal complex (cc)2057 have become dominant among Japanese MenB and have not been identified in countries other than Japan. Hypothesis/Gap Statement. The uniqueness of cc2057 N. meningitidis strains was considered to be epidemiologically of importance, and some genetic features could be hidden in the genome of cc2057 meningococci. Method. We investigated 22 cc2057 MenB and one cc2057 MenY using whole genome sequencing (WGS) and also predicted the potential coverage of 4CMenB and bivalent rLP2086 vaccines in silico. Results. cc2057 N. meningitidis strains were phylogenetically assigned to two clades. Three hypothetical genes homologous to those in Neisseria lactamica and sequences related to a new CRISPR Cas9 system were found only in the genome of cc2057 strains. Moreover, one cc2057 MenY strain was presumed to be capsular-switched at the capsule synthesis (cps) locus. The potential coverage of 4CMenB and rLP2086 for cc2057 MenB strains was estimated to be very low. Conclusion. To the best of our knowledge, this is the first study to provide genetic insights from epidemiologically unique N. meningitidis cc2057 strains isolated only in Japan, an island country.

Objectives Ceftriaxone (CRO) resistance is spreading worldwide, and hindering the effective treatment of gonococcal infections. This study developed a detection system for the genomic DNA of CRO-resistant Neisseria gonorrhoeae (N. gonorrhoeae) strains, in order to improve the surveillance of antimicrobial resistance. Methods A real-time PCR assay targeting the penA gene of recently isolated CRO-resistant N. gonorrhoeae strains was designed. Primer and probe sequence information was obtained from sequence comparisons between penA of Neisseria spp. and penA of CRO-resistant N. gonorrhoeae strains. Results Using this assay, a positive reaction was observed using the genomic DNA of three strains (GU140106, FC428, and A8806). The assay was evaluated using genomic DNA of 204 N. gonorrhoeae and 95 Neisseria spp. isolates with known minimum inhibitory concentrations of CRO. Following PCR assays for these strains, three FC428-related strains were positively identified, which possessed penA-60.001, whereas the remaining 201 N. gonorrhoeae strains and 95 Neisseria spp. strains were negative. Conclusions A real-time PCR-based assay was designed to detect the genomic DNA of strains harbouring mosaic penA-59.001 (GU140106), penA-60.001 (FC428), and penA-64.001 (A8806) alleles and to discriminate them from N. gonorrhoeae and Neisseria spp. strains harbouring other genes.

Antimicrobial resistance in Neisseria gonorrhoeae is a global health concern. Strains from two internationally circulating sequence types, ST-7363 and ST-1901, have acquired resistance to treatment with third-generation cephalosporins mainly due to the emergence of mosaic penA alleles. These two STs were first detected in Japan; however, when and how the mosaic penA alleles emerged and spread to other countries remains unknown. Here, we addressed the evolution of penA alleles by obtaining complete genomes from three Japanese ST-1901 clinical isolates harboring mosaic penA allele 34 (penA-34) dating from 2005 and generating a phylogenetic representation of 1,075 strains sampled from 37 countries. We also sequenced the genomes of 103 Japanese ST-7363 N. gonorrhoeae isolates from 1996-2005 and reconstructed a phylogeny including 88 previously sequenced genomes. Based on an estimate of the time of emergence of ST-1901 harboring mosaic penA-34 and ST-7363 harboring mosaic penA-10, and >300 additional genome sequences of Japanese strains representing multiple STs isolated in 1996-2015, we suggest that penA-34 in ST-1901 was generated from penA-10 via recombination with another Neisseria species, followed by a second recombination event with a gonococcal strain harboring wildtype penA-1. Following the acquisition of penA-10 in ST-7363, a dominant sub-lineage rapidly acquired fluoroquinolone resistance mutations at GyrA 95 and ParC 87-88, possibly due to independent mutations rather than horizontal gene transfer. Literature data suggest the emergence of these resistance determinants may reflect selection from the standard treatment regimens in Japan at that time. Our findings highlight how recombination and antibiotic use across and within Neisseria species intersect in driving the emergence and spread of drug-resistant gonorrhea.Author summaryAntimicrobial resistance is recognized as one of the greatest threats to human health, and Neisseria gonorrhoeae resistance is classified as one of the most urgent. The two major internationally spreading lineages resistant. to first line drugs likely originated in Japan, but when and how their genetic resistance determinants emerged remain unknown. In this study, we conducted an evolutionary analysis using clinical N. gonorrhoeae isolates from 37 countries, including a historical collection of Japanese isolates, to investigate the emergence of resistance in each of the two major lineages. We showed that the penA allele responsible for resistance to cephalosporins, the first-line treatment for gonorrhea, was possibly generated by two recombination events, one from another Neisseria species and one from another N. gonorrhoeae lineage. We also showed that mutations responsible for resistance to a previously widely used antibiotic treatment occurred twice independently in one of the two major lineages. The emergence of the genetic resistance determinants potentially reflects selection from the standard treatment regimen at that time. Our findings highlight how recombination (horizontal gene transfer) and antibiotic use across and within a bacterial species intersect in driving the emergence and spread of antimicrobial resistance genes and mutations.

Objectives Ceftriaxone resistance in Neisseria gonorrhoeae is a major public health concern globally because a high-dose (1 g) injection of ceftriaxone is the only remaining option for empirical monotherapy of gonorrhoea. The ceftriaxone-resistant gonococcal strain FC428, cultured in Osaka in 2015, is suspected to have spread nationally and internationally. We describe the complete finished genomes of FC428 and two closely related isolates from Osaka in 2015, and examine the genomic epidemiology of these isolates plus three ceftriaxone-resistant gonococcal isolates from Osaka and Hyogo in 2016-17 and four ceftriaxone-resistant gonococcal isolates cultured in 2017 in Australia, Canada and Denmark. Methods During 2015-17, we identified six ceftriaxone-resistant gonococcal isolates through our surveillance systems in Kyoto, Osaka and Hyogo. Antimicrobial susceptibility testing (six antimicrobials) was performed using Etest. Complete whole-genome sequences of the first three isolates (FC428, FC460 and FC498) from 2015 were obtained using PacBio RS II and Illumina MiSeq sequencing. The three complete genome sequences and draft genome sequences of the three additional Japanese (sequenced with Illumina MiSeq) and four international ceftriaxone-resistant isolates were compared. Results Detailed genomic analysis suggested that the Japanese isolates (FC428, FC460, FC498, KU16054, KM383 and KU17039) and the four international MLST ST1903 isolates from Australia, Canada and Denmark formed four linked subclades. Conclusions Using detailed genomic analysis, we describe the clonal expansion of the ceftriaxone-resistant N. gonorrhoeae strain FC428, initially identified in 2015 in Japan, and closely related isolates. FC428 and its close relatives show some genomic diversity, suggesting multiple genetic subclades are already spreading internationally.

We identified and characterized the first 2 Neisseria gonorrhoeae strains with high-level azithromycin resistance isolated in Japan. These were in the clade of ceftriaxone- and azithromycin-resistant strains isolated in Australia and the United Kingdom. The multilocus sequence typing, N. gonorrhoeae multiantigen sequence typing, and N. gonorrhoeae sequence typing for antimicrobial resistance types of these strains were found in gonococci from eastern Asia.

We identified and characterized the first 2 Neisseria gonorrhoeae strains with high-level azithromycin resistance isolated in Japan. These were in the clade of ceftriaxone- and azithromycin-resistant strains isolated in Australia and the United Kingdom. The multilocus sequence typing, N. gonorrhoeae multiantigen sequence typing, and N. gonorrhoeae sequence typing for antimicrobial resistance types of these strains were found in gonococci from eastern Asia.

Background Japan has seen a substantial increase in syphilis cases since 2013 and Tokyo and Osaka prefectures accounted for about 40% of all cases in Japan. Therefore, focusing on these 2 prefectures, we assessed syphilis cases detected during 2017–2018, combining epidemiological information with molecular typing data. Methods Using data from surveillance reports, we described syphilis cases by gender, age, transmission route, and stage of syphilis. Clinical specimens were collected from syphilis patients in Tokyo and Osaka prefectures. Molecular typing was performed by analyzing Treponema pallidum arp, tpr, and tp0548 genes, with partial sequencing of the 23S rRNA genes for macrolide resistance. Results Between 2017 and 2018, the number of syphilis cases increased from 3934 to 4588 among males and 1895 to 2414 among females, with similar age and gender distributions during the period. The predominant strain type was 14d/f (71%, 73/103), found more frequently in women who have sex with men (86%, 25/29) and men who have sex with women (83%, 39/47) than in men who have sex with men (MSM) (33%, 9/27). The majority of the strains from heterosexuals (97%, 76/78) were macrolide-resistant, considerably higher than those from MSM (59%, 20/34). The molecular profiles in each sexual-transmission group remained similar during the 2 years. Conclusions The epidemiological and molecular features of syphilis remained similar throughout the period, with consistent differences in strain type and macrolide resistance distributions between MSM and heterosexual cases. These findings suggest a predominantly heterosexual epidemic where the dynamics of syphilis transmission remained unchanged during 2017–2018.

Ceftriaxone (CRO) is widely used as the first-line treatment for gonococcal infections. However, CRO-resistant Neisseria gonorrhoeae strains carrying mosaic penA -60.001 have emerged recently and disseminated worldwide. To meet the urgent need to detect these strains, we report here a loop-mediated isothermal amplification (LAMP) assay system that targets N. gonorrhoeae penA -60.001.

We determined minimum inhibitory concentrations (MICs) of 41 antimicrobial agents for 73 clinical strains of Haemophilus influenzae isolated from the urethra of men with acute urethritis and/or epididymitis and examined the strains for the production of β-lactamase. We also compared their antimicrobial susceptibilities with those of H. influenzae strains from respiratory tract or otorhinolaryngological infections that were reported in Japan. The proportion of β-lactamase-nonproducing ampicillin-resistant strains from acute urethritis and/or epididymitis appeared to be lower, but that of β-lactamase-producing ampicillin-resistant strains appeared to be higher, compared with those from respiratory tract or otorhinolaryngological infections. However, their antimicrobial susceptibilities to a variety of other antimicrobial agents would be similar to those from respiratory tract or otorhinolaryngological infections. Almost all of the strains of H. influenzae from acute urethritis and/or epididymitis were susceptible to the agents, including ceftriaxone, quinolones, macrolides, and tetracyclines, commonly prescribed for treatment of acute urethritis based on the MIC breakpoints recommended by the Clinical and Laboratory Standards Institute. Ceftriaxone and quinolones could be effective on H. influenzae-induced urethritis. However, azithromycin treatment failures were reported in acute urethritis caused by H. influenzae strains considered susceptible to azithromycin. Further studies will be needed to determine MIC breakpoints of antimicrobial agents, which are recommended for treatment of urogenital infections, for H. influenzae strains causing these infections. Nevertheless, this study provides useful data regarding antimicrobial susceptibilities of H. influenzae strains isolated from the urogenital tract, which have rarely been studied.

There have been few comprehensive studies on Haemophilus influenza-positive urethritis.In this retrospective study, we enrolled 68 men with H. influenzae-positive urethritis, including coinfections with Neisseria gonorrhoeae, Chlamydia trachomatis, and/or genital mycoplasmas: 2, 3, 20, and 43 treated with ceftriaxone, levofloxacin, sitafloxacin, and extended-release azithromycin (azithromycin-SR), respectively. We assessed microbiological outcomes in 54 men and clinical outcomes in 46 with H. influenzae-positive monomicrobial nongonococcal urethritis. We determined minimum inhibitory concentrations (MICs) of 6 antimicrobial agents for 59 pretreatment isolates.H. influenzae was eradicated from the men treated with ceftriaxone, levofloxacin, or sitafloxacin. The eradication rate with azithromycin-SR was 85.3%. The disappearance or alleviation of urethritis symptoms and the decreases in leukocyte counts in first-voided urine were significantly associated with the eradication of H. influenzae after treatment. For the isolates, ceftriaxone, levofloxacin, sitafloxacin, azithromycin, tetracycline, and doxycycline MICs were ≤0.008-0.25, 0.008-0.5, 0.001-0.008, 0.12-1, 0.25-16, and 0.25-2 μg/mL, respectively. The azithromycin MICs for 3 of 4 strains persisting after azithromycin-SR administration were 1 μg/mL. H. influenzae with an azithromycin MIC of 1 μg/mL increased chronologically.H. influenzae showed good responses to the chemotherapies for urethritis. The significant associations of the clinical outcomes of the chemotherapies with their microbiological outcomes suggested that H. influenzae could play pathogenic roles in urethritis. All isolates, except for one with decreased susceptibility to tetracyclines, were susceptible to the examined agents. However, the increase in H. influenzae with an azithromycin MIC of 1 μg/mL might threaten efficacies of azithromycin regimens on H. influenzae-positive urethritis.

Ceftriaxone (CRO) is widely used as the first-line treatment for gonococcal infections. However, CRO-resistant Neisseria gonorrhoeae strains carrying mosaic penA-60.001 have emerged recently and disseminated worldwide. To meet the urgent need to detect these strains, we report here a loop-mediated isothermal amplification (LAMP) assay system that targets N. gonorrhoeae penA-60.001. This assay system can differentiate N. gonorrhoeae strains carrying mosaic penA-60.001 from strains carrying other penA alleles.

In recent years, syphilis notifications have increased dramatically in Japan. We carried out molecular typing and macrolide resistance analyses of Treponema pallidum subsp. pallidum samples collected from patients at four clinics and a hospital in Tokyo and Osaka prefectures in 2017. The macrolide resistant strain type 14d/f (SS14-like clade) was found in significantly more cases of syphilis among heterosexuals than in those among men who have sex with men (MSM); i.e., 79% (31/39) of the strains from heterosexuals were 14d/f compared to 37% (7/19) of those from MSM (odds ratio [OR], 6.6; 95% confidence interval [CI], 1.7 to 26.7; P = 0.002). In addition, 83% (50/60) of the strains were identified as macrolide resistant with an A2058G mutation in the 23S rRNA gene; 90% (35/39) of the strains from heterosexuals were macrolide resistant compared to 58% (11/19) of those from MSM. The odds of having the resistant mutation were considerably higher in the former (OR, 6.4; 95% CI, 1.3 to 33.5; P = 0.02). Heterosexual women and heterosexual men showed similar distributions, and the association remained the same when restricted to men. The strain type distribution and the prevalence of macrolide resistance differed substantially between syphilis strains from heterosexual cases and from MSM cases, suggesting distinct epidemiologic profiles for the two communities and providing important insight into the dynamics of syphilis in Japan.

Objectives To detect microorganisms responsible for male acute urethritis and to define the microbiology of non-gonococcal urethritis. Methods The present study comprised 424 men with symptoms and signs compatible with acute urethritis. Their urethral swabs and first-voided urine underwent detection of the microorganisms. Demographic characteristics and clinical features of Mycoplasma genitalium-, Ureaplasma urealyticum-, Haemophilus influenza-, adenovirus- or Herpes simplex virus-positive monomicrobial non-gonococcal urethritis, or all-examined microorganism-negative urethritis in heterosexual men were compared with urethritis positive only for Chlamydia trachomatis. Results Neisseria gonorrhoeae was detected in 127 men (30.0%). In 297 men with non-gonococcal urethritis, C. trachomatis was detected in 143 (48.1%). In 154 men with non-chlamydial non-gonococcal urethritis, M. genitalium (22.7%), M. hominis (5.8%), Ureaplasma parvum (9.1%), U. urealyticum (19.5%), H. influenzae (14.3%), Neisseria meningitidis (3.9%), Trichomonas vaginalis (1.3%), human adenovirus (16.2%), and Herpes simplex virus types 1 (7.1%) and 2 (2.6%) were detected. Although some features of monomicrobial non-chlamydial non-gonococcal urethritis or all-examined microorganism-negative urethritis were significantly different from those of monomicrobial chlamydial non-gonococcal urethritis, most features were superimposed. Conclusions Predicting causative microorganisms in men with non-gonococcal urethritis based on demographic and clinical features is difficult. However, the present study provides useful information to better understand the microbiological diversity in non-gonococcal urethritis, and to manage patients with non-gonococcal urethritis appropriately.

The first extensively drug resistant (XDR) Neisseria gonorrhoeae strain with high resistance to the extended-spectrum cephalosporin ceftriaxone was identified in 2009 in Japan, but no other strain with this antimicrobial-resistance profile has been reported since. However, surveillance to date has been based on phenotypic methods and sequence typing, not genome sequencing. Therefore, little is known about the local population structure at the genomic level, and how resistance determinants and lineages are distributed and evolve. We analysed the whole-genome sequence data and the antimicrobial-susceptibility testing results of 204 strains sampled in a region where the first XDR ceftriaxone-resistant N. gonorrhoeae was isolated, complemented with 67 additional genomes from other time frames and locations within Japan. Strains resistant to ceftriaxone were not found, but we discovered a sequence type (ST)7363 sub-lineage susceptible to ceftriaxone and cefixime in which the mosaic penA allele responsible for reduced susceptibility had reverted to a susceptible allele by recombination. Approximately 85 % of isolates showed resistance to fluoroquinolones (ciprofloxacin) explained by linked amino acid substitutions at positions 91 and 95 of GyrA with 99 % sensitivity and 100 % specificity. Approximately 10 % showed resistance to macrolides (azithromycin), for which genetic determinants are less clear. Furthermore, we revealed different evolutionary paths of the two major lineages: single acquisition of penA X in the ST7363-associated lineage, followed by multiple independent acquisitions of the penA X and XXXIV in the ST1901-associated lineage. Our study provides a detailed picture of the distribution of resistance determinants and disentangles the evolution of the two major lineages spreading worldwide.

The first extensively drug resistant (XDR) Neisseria gonorrhoeae strain with high resistance to the extended-spectrum cephalosporin ceftriaxone was identified in 2009 in Japan, but no other strain with this antimicrobial-resistance profile has been reported since. However, surveillance to date has been based on phenotypic methods and sequence typing, not genome sequencing. Therefore, little is known about the local population structure at the genomic level, and how resistance determinants and lineages are distributed and evolve. We analysed the whole-genome sequence data and the antimicrobial-susceptibility testing results of 204 strains sampled in a region where the first XDR ceftriaxone-resistant N. gonorrhoeae was isolated, complemented with 67 additional genomes from other time frames and locations within Japan. Strains resistant to ceftriaxone were not found, but we discovered a sequence type (ST)7363 sub-lineage susceptible to ceftriaxone and cefixime in which the mosaic penA allele responsible for reduced susceptibility had reverted to a susceptible allele by recombination. Approximately 85 % of isolates showed resistance to fluoroquinolones (ciprofloxacin) explained by linked amino acid substitutions at positions 91 and 95 of GyrA with 99 % sensitivity and 100 % specificity. Approximately 10 % showed resistance to macrolides (azithromycin), for which genetic determinants are less clear. Furthermore, we revealed different evolutionary paths of the two major lineages: single acquisition of penA X in the ST7363-associated lineage, followed by multiple independent acquisitions of the penA X and XXXIV in the ST1901-associated lineage. Our study provides a detailed picture of the distribution of resistance determinants and disentangles the evolution of the two major lineages spreading worldwide.

In recent years, syphilis notifications have increased dramatically in Japan. We performed molecular typing and analyzed macrolide resistance ofTreponema pallidumsamples collected from four clinics and a hospital in Tokyo and Osaka prefectures in 2017.Macrolide resistant strain type 14d/f was found significantly more in heterosexual syphilis cases compared with those strains identified in men who have sex with men (MSM) syphilis cases. The proportion of 14d/f among heterosexuals was 79% (31/39) compared to 37% (7/19) among MSM [OR, 6.6 (95% CI, 1.7 to 26.7); P=0.002]. 83% (50/60) of the strains were identified as macrolide resistant with an A2058G mutation at the 23S rRNA gene. 90% (35/39) of the heterosexual strains were macrolide resistant, relative to 58% (11/19) of MSM strains; the odds of having the resistant mutation was considerably higher in heterosexuals compared with MSM [OR, 6.4 (95% CI, 1.3 to 33.5); P=0.02]. Heterosexual females and males showed similar distributions, and the results remained the same when restricted to men.The strain type distribution and frequency of macrolide resistance differed substantially between heterosexual and MSM syphilis samples, suggesting distinct epidemiologic profiles for the two communities and insight into syphilis transmission dynamics in Japan.

Mosaic penA alleles have caused most of the cephalosporin resistance in Neisseria gonorrhoeae , but their evolution is mostly unknown. The penA gene from Neisseria cinerea strain AM1601 (ceftriaxone MIC, 1.0 μg/ml) caused ceftriaxone resistance (MIC, 1 μg/ml) in a ceftriaxone-susceptible gonococcal strain. The 3′-terminal half of AM1601 penA was almost identical to that of the ceftriaxone-resistant gonococcal GU140106 and FC428 strains. N. cinerea can serve as a reservoir of ceftriaxone resistance-mediating penA sequences that can be transferred to gonococci.

Mosaic penA alleles have caused most of the cephalosporin resistance in Neisseria gonorrhoeae, but their evolution is mostly unknown. The penA gene from Neisseria cinerea strain AM1601 (ceftriaxone MIC, 1.0 μg/ml) caused ceftriaxone resistance (MIC, 1 μg/ml) in a ceftriaxone-susceptible gonococcal strain. The 3′-terminal half of AM1601 penA was almost identical to that of the ceftriaxone-resistant gonococcal GU140106 and FC428 strains. N. cinerea can serve as a reservoir of ceftriaxone resistance-mediating penA sequences that can be transferred to gonococci.

Introduction Gonorrhoea is a global health concern because N. gonorrhoeae has now acquired resistance to antibiotics including the 3 rd generation cephalosporin, ceftriaxone. Mosaic structure in penicillin-binding protein 2 gene ( penA ) is the main cause of ceftriaxone resistance which is formed by natural transformation of DNA of ceftriaxone-resistant (CRO R ) commensal Neisseria spp. However, none of the previous studies has fully elucidated the source of transformed DNA. In this study, we show that genetic comparison between CRO R - N. gonorrhoeae strains (GU140106 and FC428) and CRO R – Neisseria commensals. Methods CRO R - Neisseria commensals were isolated from pharyngeal swabs. Genome sequence was obtained by MiSeq, Illumina, and the sequence of penA flanking region ( mraW-NGO 1540- penA-murE-dcaA ) was obtained using the N. gonorrhoeae FA1090 as a reference sequence. Alignment of the compared sequences were prepared by CLUSTALW. Species identification of Neisseria commensals was performed using phylogeny constructed by 53 ribosomal proteins ( rps ) sequences. Results Based on the sequence similarity of penA gene, two CRO R - Neisseria commensals were speculated to be the origin of each mosaic penA of GU140106 and FC428. Both of the candidates were N. cinerea according to the rps phylogeny. The DNA region including penA originated from N. cinerea which consist the part of mosaic penA in the CRO R - N. gonorrhoeae was about 1.3 kb including of parts of penA and murE . Further analysis revealed that mosaic penA of GU140106 occurred by recombination between CRO R - N. cinerea and CRO S - N. gonorrhoeae which the NG-MAST type was same with GU140106. The mosaic penA of FC428 was also thought to emerged in the same way with GU140106. However, there was a limitation because of the lack of CRO S -N. gonorrhoeae that has the same NG-MAST type with FC428. Conclusion The two CRO R -N. gonorrhoeae , GU140106 and FC428, might acquire resistance by homologous recombination with Neisseria commensals, and N. cinerea might be the donor of mosaic penA which causes resistance to ceftriaxone in N. gonorrhoeae .

Objectives Antimicrobial resistance in Neisseria gonorrhoeae is a major public health concern globally. We report the first verified treatment failure of gonorrhoea with 2 g of azithromycin (extended-release formulation) in Japan and characteristics of the corresponding N. gonorrhoeae isolates. Methods Pre- and post-treatment isolates (n = 4) were investigated by Etest for antimicrobial susceptibility. The isolates were examined for molecular epidemiology by multilocus sequence typing (MLST), N. gonorrhoeae multi-antigen sequence typing (NG-MAST) and multiple-locus variable-number tandem repeat analysis (MLVA), and for the presence of azithromycin resistance determinants (23S rRNA gene mutations, erm genes and mtrR mutations). Results All isolates were resistant to azithromycin (MIC 4 mg/L) and ciprofloxacin, but remained susceptible to cefixime, ceftriaxone and spectinomycin. All isolates were assigned to MLST ST1901 and NG-MAST ST1407 and three of four isolates possessed MLVA profile 8-3-21-16-1. All isolates contained the previously described C2599T mutation (N. gonorrhoeae numbering) in all four 23S rRNA alleles and the previously described single-nucleotide (A) deletion in the mtrR promoter region. Conclusions This verified treatment failure occurred in a patient infected with an MLST ST1901/NG-MAST ST1407 strain of N. gonorrhoeae. While this international strain commonly shows resistance or decreased susceptibility to multiple antimicrobials, including extended-spectrum cephalosporins, the strain reported here remained fully susceptible to the latter antimicrobials. Hence, two subtypes of azithromycin-resistant gonococcal MLST ST1901/NG-MAST ST1407 appear to have evolved and to be circulating in Japan. Azithromycin should not be recommended as a single antimicrobial for first-line empirical treatment of gonorrhoea.

We have characterized in detail a new ceftriaxone- and multidrug-resistant Neisseria gonorrhoeae strain (FC428) isolated in Japan in 2015. FC428 differed from previous ceftriaxone-resistant strains and contained a novel mosaic penA allele encoding a new mosaic penicillin-binding protein 2 (PBP 2). However, the resistance-determining 3′-terminal region of penA was almost identical to the regions of two previously reported ceftriaxone-resistant strains from Australia and Japan, indicating that both ceftriaxone-resistant strains and conserved ceftriaxone resistance-determining PBP 2 regions might spread.

Recently, the first Neisseria gonorrhoeae strain (H041) that is highly resistant to the extended-spectrum cephalosporin (ESC) ceftriaxone, the last remaining option for empirical first-line treatment, was isolated. We performed a detailed characterization of H041, phenotypically and genetically, to confirm the finding, examine its antimicrobial resistance (AMR), and elucidate the resistance mechanisms. H041 was examined using seven species-confirmatory tests, antibiograms (30 antimicrobials), porB sequencing, N. gonorrhoeae multiantigen sequence typing (NG-MAST), multilocus sequence typing (MLST), and sequencing of ESC resistance determinants ( penA , mtrR , penB , ponA , and pilQ ). Transformation, using appropriate recipient strains, was performed to confirm the ESC resistance determinants. H041 was assigned to serovar Bpyust, MLST sequence type (ST) ST7363, and the new NG-MAST ST4220. H041 proved highly resistant to ceftriaxone (2 to 4 μg/ml, which is 4- to 8-fold higher than any previously described isolate) and all other cephalosporins, as well as most other antimicrobials tested. A new penA mosaic allele caused the ceftriaxone resistance. In conclusion, N. gonorrhoeae has now shown its ability to also develop ceftriaxone resistance. Although the biological fitness of ceftriaxone resistance in N. gonorrhoeae remains unknown, N. gonorrhoeae may soon become a true superbug, causing untreatable gonorrhea. A reduction in the global gonorrhea burden by enhanced disease control activities, combined with wider strategies for general AMR control and enhanced understanding of the mechanisms of emergence and spread of AMR, which need to be monitored globally, and public health response plans for global (and national) perspectives are important. Ultimately, the development of new drugs for efficacious gonorrhea treatment is necessary.

In early animal development, cell proliferation and differentiation are tightly linked and coordinated. It is important, therefore, to know how the cell cycle is controlled during early development. Cdc25 phosphatases activate cyclin-dependent kinases (Cdks) and thereby promote cell-cycle progression. In Xenopus laevis, three isoforms of cdc25 have been identified, viz. cdc25A, cdc25B and cdc25C. In this study, we isolated a cDNA encoding a novel Xenopus Cdc25 phosphatase (named cdc25D). We investigated the temporal and spatial expression patterns of the four cdc25 isoforms during early Xenopus development, using RT-PCR and whole-mount in situ hybridization. cdc25A and cdc25C were expressed both maternally and zygotically, whereas cdc25B and cdc25D were expressed zygotically. Both cdc25A and cdc25C were expressed mainly in prospective neural regions, whereas cdc25B was expressed preferentially in the central nervous system (CNS), such as the spinal cord and the brain. Interestingly, cdc25D was expressed in the epidermal ectoderm of the late-neurula embryo, and in the liver diverticulum endoderm of the mid-tailbud embryo. In agreement with the spatial expression patterns in whole embryos, inhibition of bone morphoge- netic protein (BMP), a crucial step for neural induction, induced an upregulation of cdc25B, but a downregulation of cdc25D in animal cap assays.These results indicate that different cdc25 isoforms are differently expressed and play different roles during early Xenopus development.

To the Editor: We report a case of urethritis caused by a novel multilocus sequence type (ST), 10651, of the ST11/electrophoretic type (ET)–37 complex Neisseria meningitidis serotype W. The patient was a man who has sex with men. We also report on the patient’s male partner, who was colonized with the same bacteria. In March 2013, a 33-year-old Japanese man sought medical care at Shirakaba Clinic (Tokyo) after experiencing a urethral discharge for 4 days. The man was HIV positive (CD4 count 649 cells/μL) but was not receiving antiretroviral therapy. Physical examination showed a mucous urethral discharge. Gram staining of a sample revealed many gram-negative diplococci phagocytosed by polymorphonuclear leukocytes. Eleven days before seeking care, the patient had oral and anal intercourse with his male partner. A diagnosis of suspected urethritis caused by Neisseria gonorrhoeae was made, and a sample of the urethral discharge was sent for culture and testing (Strand Displacement Amplification) for N. gonorrhoeae and Chlamydia trachomatis. The patient was intravenously administered a single dose of ceftriaxone (1 g) (intramuscular administration of ceftriaxone is not approved in Japan). He was also given a single dose of azithromycin (1g orally) for possible C. trachomatis urethritis (1). Six days after receiving treatment, the patient showed improvement. Results of the Strand Displacement Amplification test were negative for N. gonorrhoeae and C. trachomatis. Eight days after the patient received treatment, the culture for the urethral discharge sample was shown to be positive for N. meningitidis. Urine culture was negative 20 days after treatment. The 33-year-old male partner of the case-patient was originally from the United States and had been living in Japan for 4 years. Because of his history of sexual contact with the case-patient, he was advised to undergo a screening test for HIV and N. meningitidis. The man underwent a physical examination at our clinic 40 days after the case-patient received treatment; findings were unremarkable, and the result for HIV testing done 2 days earlier was negative. Throat and urine samples were obtained for culture, and the man was intravenously administered ceftriaxone (1 g). The urine sample culture was negative, but the throat sample culture was positive for N. meningitidis. The throat culture result was negative 10 days after the patient’s treatment. We performed cultures and tests to identify N. meningitidis, and we conducted multilocus sequence typing (MLST), serotyping, PorA typing, and pulsed-field gel electrophoresis (PFGE) as described elsewhere (2). Isolates from both men were identified as serotype W and PorA type P1.5, 2. MLST showed that the strains were ST10651 (genes analyzed: aroE:3, adk:4, fumC:3, gdh:8, pdhC:4, pgm:6, and abcZ:662). Although abcZ:662 was a novel allele, ST10651 belongs to the ST11/ET37 complex (3). We used PFGE with restriction enzyme NheI to compare the N. meningitidis strains from the case-patient and his partner; the isolates had the same PFGE pattern (Figure). Both isolates were confirmed to be a novel multilocus ST, 10651, of the ST11/ET37 complex; however, novel MLST types frequently occur. By using the E-test (Sysmex bioMerieux, Tokyo, Japan), we determined that the 2 isolates required the same minimum inhibitory concentrations (MICs) for the following antimicrobial drugs: penicillin (MIC 0.125 mg/L), ceftriaxone (MIC 0.004 mg/L), ciprofloxacin (MIC 0.004 mg/L), and azithromycin (MIC 0.25 mg/L) (4). Figure Pulsed-field gel electrophoresis (PFGE) patterns for N. meningitidis strains isolated from a man with urethritis (case 1) and his male sex partner (case 2), Japan. PFGE was performed with the restriction enzyme NheI. Results showed the same PFGE pattern ... Urethritis caused by N. meningitidis infection in men who have sex with men (MSM) has been reported, as has an association between urethritis and oral sex (5,6). Most previously reported urogenital isolates of N. meningitidis have belonged to serogroups B (5,6), Y (5,6), and C (5). Among 115 cases of N. meningitidis infection in Japan during the last 9 years, 22 (19.1%) were caused by serogroup B and 18 (15.7%) were caused by serogroup Y; only 3 (2.6%) cases were caused by serotype W (7). N. meningitidis ST11/ET37 complex is a hyperinvasive lineage. During the 1990s, the serogroup C ST11/ET37 complex was prominent in Europe and North America. However, in 2000, an outbreak of N. meningitidis serotype W infections occurred among Hajj pilgrims (8), and this serotype has now spread worldwide (3,8). Chemoprophylaxis is indicated for persons who have close contact with someone with invasive meningococcal infection (9), but there is uncertainty regarding the treatment of asymptomatic persons who have contact with someone with N. meningitidis urethritis. To avoid a reinfection cycle between the men in this study, we treated the asymptomatic, N. meningitidis–colonized male partner. Since the early 2000s, and especially since 2012, outbreaks of invasive serogroup C, ST11/ET37 complex meningococcal disease causing high rates of death have been reported among MSM in the United States and Europe (10). These outbreaks have raised policy questions concerning vaccination recommendations for HIV-infected persons and for the MSM population (10). In Japan, meningococcal vaccination has not been officially approved, and neither of the men in this study had been vaccinated against N. meningitidis. A diagnosis of urethritis is often based on Gram staining or nucleic acid amplification tests (1). However, Gram staining cannot differentiate N. meningitidis from N. gonorrhoeae, and amplification tests only detect N. gonorrhoeae. This practice makes it difficult to diagnose and access the number of cases of N. meningitidis urethritis.

The pathogenicity island termed locus of enterocyte effacement (LEE) encodes a type 3 protein secretion system, whose function is required for full virulence of enterohemorrhagic Escherichia coli (EHEC). GrlR and GrlA are LEE-encoded negative and positive regulators, respectively, for controlling transcription of the ler gene, which encodes a central activator of LEE gene expression. We previously reported that the GrlR-GrlA regulatory system controls not only the LEE genes but also flagellar gene expression in EHEC (S. Iyoda et al., J. Bacteriol. 188: 5682-5692, 2006). In order to further explore virulence-related genes under the control of the GrlR-GrlA regulatory system, we characterized a grlR -deleted EHEC O157 strain, which was found to have high and low levels of expression of LEE and flagellar genes, respectively. We report here that the grlR deletion significantly induced enterohemolysin (Ehx) activity of EHEC O157 on plates containing defibrinated sheep erythrocytes. Ehx levels were not induced in the grlR grlA double mutant strain but increased markedly by overexpression of GrlA even in the ler mutant, indicating that GrlA is responsible for this regulation. Ehx of the EHEC O157 Sakai strain is encoded by the ehxCABD genes, which are carried on the large plasmid pO157. The expression of ehxC fused with FLAG tag or a promoterless lacZ gene on pO157 was significantly induced under conditions in which GrlA was overproduced. These results together suggest that GrlA acts as a positive regulator for the ehx transcription in EHEC.

Background Neisseria gonorrhoeae strains with resistance to extended-spectrum cephalosporins (ESCs), last options for first-line monotherapy of gonorrhoea, likely emerged and initially disseminated in Japan, followed by international transmission. In recent years, multi-locus sequence typing (MLST) ST1901 and N. gonorrhoeae multiantigen sequence typing (NG-MAST) ST1407 isolates with the mosaic penicillin-binding protein (PBP) 2 XXXIV have accounted for most ESC resistance globally. Our aim was to elucidate the initial emergence and transmission of ESC-resistant strains by detailed examination of N. gonorrhoeae isolates from 1995 to 2005 in Kanagawa, Japan. Methods N. gonorrhoeae isolates were examined phenotypically (n = 690) and genetically (n = 372) by agar dilution method (cefixime, ceftriaxone and ciprofloxacin), penA gene sequencing, MLST and NG-MAST. Results Already in 1995, one cefixime-resistant (CFM-R) isolate was found, which is the first CFM-R isolate described globally. After 1996, the prevalence of CFM-R and CFM-decreased susceptibility (CFM-DS) isolates significantly increased, with the peak resistance level in 2002 (57.1 % CFM-R). In 1997–2002, the CFM-R MLST ST7363 strain type with the mosaic PBP 2 X was predominant among CFM-R/DS isolates. The first CFM-R/DS MLST ST1901 clone(s), which became the predominant CFM-R/DS strain type(s) already in 2003–2005, possessed the mosaic PBP 2 X, which was possibly originally transferred from the MLST ST7363 strains, and subsequently acquired the mosaic PBP 2 XXXIV. The first MLST ST1901 and NG-MAST ST1407 isolate was identified in Kanagawa already in 2003. Conclusions The two main internationally spread cefixime-resistant gonococcal clones, MLST ST7363 and ST1901 (NG-MAST ST1407 most frequent internationally) that also have shown their capacity to develop high-level ceftriaxone resistance (superbugs H041 and F89), likely emerged, evolved and started to disseminate in the metropolitan area, including Kanagawa, in Japan, which was followed by global transmission.

A real-time PCR assay with the cycling probe method was used to detect mutations at codons 83 and 87 in the DNA gyrase A subunit encoded by gyrA in Salmonella enterica serovar Typhi and Paratyphi A clinical isolates. The susceptibility estimated from the results of the gyrA mutation assay was consistent with that identified by the culture method using an E-test. This assay allows rapid screening of S. enterica serovar Typhi and Paratyphi A with reduced susceptibility to ciprofloxacin.

Cdc25 phosphatases activate cyclin-dependent kinases (Cdks) and thereby promote cell cycle progression. In vertebrates, Chk1 and Chk2 phosphorylate Cdc25A at multiple N-terminal sites and target it for rapid degradation in response to genotoxic stress. Here we show that Chk1, but not Chk2, phosphorylates Xenopus Cdc25A at a novel C-terminal site (Thr504) and inhibits it from C-terminally interacting with various Cdk–cyclin complexes, including Cdk1–cyclin A, Cdk1–cyclin B, and Cdk2–cyclin E. Strikingly, this inhibition, rather than degradation itself, of Cdc25A is essential for the Chk1-induced cell cycle arrest and the DNA replication checkpoint in early embryos. 14-3-3 proteins bind to Chk1-phosphorylated Thr504, but this binding is not required for the inhibitory effect of Thr504 phosphorylation. A C-terminal site presumably equivalent to Thr504 exists in all known Cdc25 family members from yeast to humans, and its phosphorylation by Chk1 (but not Chk2) can also inhibit all examined Cdc25 family members from C-terminally interacting with their Cdk–cyclin substrates. Thus, Chk1 but not Chk2 seems to inhibit virtually all Cdc25 phosphatases by a novel common mechanism.

In Xenopus embryos, cell cycle elongation and degradation of Cdc25A (a Cdk2 Tyr15 phosphatase) occur naturally at the midblastula transition (MBT), at which time a physiological DNA replication checkpoint is thought to be activated by the exponentially increased nucleo-cytoplasmic ratio. Here we show that the checkpoint kinase Chk1, but not Cds1 (Chk2), is activated transiently at the MBT in a maternal/zygotic gene product-regulated manner and is essential for cell cycle elongation and Cdc25A degradation at this transition. A constitutively active form of Chk1 can phosphorylate Cdc25A in vitro and can target it rapidly for degradation in pre-MBT embryos. Intriguingly, for this degradation, however, Cdc25A also requires a prior Chk1-independent phosphorylation at Ser73. Ectopically expressed human Cdc25A can be degraded in the same way as Xenopus Cdc25A. Finally, Cdc25A degradation at the MBT is a prerequisite for cell viability at later stages. Thus, the physiological replication checkpoint is activated transiently at the MBT by developmental cues, and activated Chk1, only together with an unknown kinase, targets Cdc25A for degradation to ensure later development.

Few live attenuated vaccines protect against multiple serotypes of bacterial pathogen because host serotype-specific immune responses are limited to the serotype present in the vaccine strain. Here, immunization with a mutant of Shigella flexneri 2a protected guinea pigs against subsequent infection by S. dysenteriae type 1 and S. sonnei strains. This deletion mutant lacked the RNA-binding protein Hfq leading to increased expression of the type III secretion system via loss of regulation, resulting in attenuation of cell viability through repression of stress response sigma factors. Such increased antigen production and simultaneous attenuation were expected to elicit protective immunity against Shigella strains of heterologous serotypes. Thus, the vaccine potential of this mutant was tested in two guinea pig models of shigellosis. Animals vaccinated in the left eye showed fewer symptoms upon subsequent challenge via the right eye, and even survived subsequent intestinal challenge. In addition, oral vaccination effectively induced production of immunoglobulins without severe side effects, again protecting all animals against subsequent intestinal challenge with S. dysenteriae type 1 or S. sonnei strains. Antibodies against common virulence proteins and the O-antigen of S. flexneri 2a were detected by immunofluorescence microscopy. Reaction of antibodies with various strains, including enteroinvasive Escherichia coli, suggested that common virulence proteins induced protective immunity against a range of serotypes. Therefore, vaccination is expected to cover not only the most prevalent serotypes of S. sonnei and S. flexneri 2a, but also various Shigella strains, including S. dysenteriae type 1, which produces Shiga toxin., Author summary An ideal vaccine should show a broad range of protective efficacy against all serotypes of a particular pathogen. Variations in the structural lipopolysaccharide “O”-antigen mean that it is difficult to induce protection against multiple serotype Shigella strains using a single serotype immunogen. Here, we examined vaccination effects of an attenuated S. flexneri hfq mutant strain overexpressing virulence proteins common to all Shigella serotypes, which was identified from our studies on temperature and osmotic-dependent regulation of the type III secretion system: an essential virulence machinery among Shigella and enteroinvasive Escherichia coli species. The deletion mutant lacked the RNA-binding protein Hfq, which led to increased expression of the type III secretion system via loss of regulation, resulting in attenuation of cell viability through repression of stress response sigma factors. Immunization with the hfq mutant of S. flexneri 2a induced systemic immunity and cross-protective efficacy against two different serotypes of Shigella strain: S. dysenteriae type 1 and. S. sonnei. Detection of anti-Shigella antibodies against various strains with different serotypes suggests that generation of antibodies specific for common virulence proteins affords cross-protection against Shigella strains of multiple serotypes.

Ten penicillinase-producingNeisseria gonorrhoeae(PPNG) strains isolated from 2000 to 2008 were characterized by multilocus sequence typing, multiantigen sequence typing, and plasmid typing. Sequence analysis showed that 8 strains contained a TEM-1 β-lactamase gene. However, two other genetically distinct PPNG strains, isolated in 2004 and 2008, each contained a TEM-135 β-lactamase on different plasmids, a Toronto/Rio type R plasmid and an Asia type R plasmid, suggesting independent origins of these PPNG strains.

A total of 122 Neisseria gonorrhoeae isolated in the Tokyo metropolitan area in 2005-2011 were collected and analyzed by N. gonorrhoeae multiantigen sequence typing (NG-MAST) and for their susceptibility to azithromycin and ceftriaxone. All 122 strains were susceptible to ceftriaxone, but 8 strains were azithromycin-resistant, defined as an azithromycin MIC ≥ 1 μg/ml. The 8 azithromycin-resistant strains were in 6 NG-MAST types, 3 strains in NG-MAST type 1407 and each of the other 5 strains in a different NG-MAST type. NG-MAST type 1407 strains are multidrug-resistant and are disseminated worldwide.

In 2009, the first high-level ceftriaxone-resistant Neisseria gonorrhoeae strain (H041) was isolated in Kyoto, Japan. The present study describes an intensified surveillance (antimicrobial resistance and molecular typing) of Neisseria gonorrhoeae isolates in Kyoto and its neighboring prefecture Osaka, Japan, in 2010 to 2012, which was initiated after the identification of H041. From April 2010 to March 2012, 193 N. gonorrhoeae isolates were collected and the MICs (μg/ml) to six antimicrobials, including ceftriaxone, were determined. All isolates showed susceptibility to ceftriaxone and cefixime (MIC values, N. gonorrhoeae multiantigen sequence typing (NG-MAST) revealed that 12 (63%) of the 19 isolates with decreased susceptibility to ceftriaxone (MIC > 0.064 μg/ml) were of ST1407. NG-MAST ST1407 was also the most prevalent ST (16.1%; 31 of 193 isolates). In those NG-MAST ST1407 strains, several mosaic type penA alleles were found, including SF-A type (penicillin binding protein 2 allele XXXIV) and its derivatives. These were confirmed using transformation of the penA mosaic alleles as critical determinants for enhanced cefixime and ceftriaxone MICs. The intensified surveillance in Kyoto and Osaka, Japan, did not identify any dissemination of the high-level ceftriaxone-resistant N. gonorrhoeae strain H041, suggesting that H041 might have caused only a sporadic case and has not spread further.

Neisseria gonorrhoeae is a major public health problem globally, especially because the bacterium has developed resistance to most antimicrobials introduced for first-line treatment of gonorrhea. In the present study, 96 N. gonorrhoeae isolates with high-level resistance to penicillin from 121 clinical isolates in Thailand were examined to investigate changes related to their plasmid-mediated penicillin resistance and their molecular epidemiological relationships. A β-lactamase (TEM) gene variant, bla TEM-135 , that may be a precursor in the transitional stage of a traditional bla TEM-1 gene into an extended-spectrum β-lactamase (ESBL), possibly causing high resistance to all extended-spectrum cephalosporins in N. gonorrhoeae , was identified. Clonal analysis using multilocus sequence typing (MLST) and N. gonorrhoeae multiantigen sequence typing (NG-MAST) revealed the existence of a sexual network among patients from Japan and Thailand. Molecular analysis of the bla TEM-135 gene showed that the emergence of this allele might not be a rare genetic event and that the allele has evolved in different plasmid backgrounds, which results possibly indicate that it is selected due to antimicrobial pressure. The presence of the bla TEM-135 allele in the penicillinase-producing N. gonorrhoeae population may call for monitoring for the possible emergence of ESBL-producing N. gonorrhoeae in the future. This study identified a bla TEM variant ( bla TEM-135 ) that is a possible intermediate precursor for an ESBL, which warrants international awareness.

The locus of enterocyte effacement (LEE) pathogenicity island is required for the intimate adhesion of enterohemorrhagic Escherichia coli (EHEC) to the intestinal epithelial cells. GrlR and GrlA are LEE-encoded negative and positive regulators, respectively. The interaction of these two regulators is important for controlling the transcription of LEE genes through Ler, a LEE-encoded central activator for the LEE. The GrlR-GrlA regulatory system controls not only LEE but also the expression of the flagellar and enterohemolysin (Ehx) genes in EHEC. Since Ehx levels were markedly induced in a grlR mutant but not in a grlR grlA double mutant and significantly increased by overexpression of GrlA in a ler mutant, GrlA is responsible for this regulation (T. Saitoh et al., J. Bacteriol. 190: 4822-4830, 2008). In this study, additional investigations of the regulation of ehx gene expression determined that Ler also acts as an activator for Ehx expression without requiring GrlA function. We recently reported that the LysR-type regulator LrhA positively controls LEE expression (N. Honda et al., Mol. Microbiol. 74: 1393-1411, 2009). The hemolytic activity of the lrhA mutant strain of EHEC was lower than that of the wild-type strain, and LrhA markedly induced ehx transcription in an E. coli K-12 strain, suggesting that LrhA also activates the transcription of ehx without GrlA and Ler. Gel mobility shift assays demonstrated that Ler and LrhA directly bind to the regulatory region of ehxC . Together, these results indicate that transcription of ehx is positively regulated by Ler, GrlA, and LrhA, which all act as positive regulators for LEE expression.

In Neisse ria gonorrhoeae , the mosaic type of penA , which encodes penicillin-binding protein 2 (PBP 2), is associated with reduced susceptibility to oral cephalosporins. To investigate the relatedness of N. gonorrhoeae clinical isolates with reduced susceptibility, we sequenced the penA genes of 32 isolates. Five different amino acid sequence types of PBP 2 were identified, but all seemed to be derivatives of pattern X of PBP 2 (PBP 2-X). However, multilocus sequence typing of the isolates showed that the isolates belonged to six different sequence types. As PBP 2-X was identified in three different sequence types, horizontal transfer of the penA allele encoding PBP2-X was suggested. We demonstrated that the penA gene could be transferred from an isolate with reduced susceptibility to a sensitive isolate by natural transformation. Comparison of the sequence of the penA -flanking regions of 12 transformants with those of the donor and the recipient suggested that at least a 4-kb DNA segment, including the penA gene, was transferred. During horizontal transfer, some of the penA alleles also acquired variations due to point mutations and genetic exchange within the allele. Our results provide evidence that the capacity for natural transformation in N. gonorrhoeae plays a role in the spread of chromosomal antibiotic resistance genes and the generation of diversity in such genes.