Macrolide and fluoroquinolone resistance is uncommon in clinical strains of Chlamydia trachomatis.

We analyzed the 23S rRNA, gyrA and parC genes of Chlamydia trachomatis DNAs from men with urethritis and determined microbiological outcomes of an extended-release azithromycin (azithromycin-SR) regimen (2 g once daily for 1 day) and a sitafloxacin regimen (100 mg twice daily for 7 days) for chlamydial urethritis to clarify the macrolide and fluoroquinolone resistance status of clinical strains of C. trachomatis. We amplified the portions of 2 alleles of the 23S rRNA gene and the gyrA and parC genes from C. trachomatis DNAs in 284 first-voided urine specimens from men with chlamydial urethritis by PCR and sequenced their PCR products. We enrolled 369 men with chlamydial urethritis, comprising 314 and 55 treated with the azithromycin-SR regimen and the sitafloxacin regimen, respectively. Alleles 1 and/or 2 of the 23S rRNA gene were analyzed in 162 specimens. No mutations were found in the sequenced regions, including the central portion of domain V. The gyrA and parC genes were analyzed in 118 and 113 specimens, respectively. No amino acid changes were found within the quinolone resistance-determining region of the gyrA gene and in the sequenced region of the parC gene. The microbiological outcomes of the azithromycin-SR and sitafloxacin regimens were assessed in 176 and 30 men, respectively. The eradication rates were 96.0% (95% CI 93.1%-98.9%) for the azithromycin-SR regimen and 100% for the sitafloxacin regimen. Clinical strains of C. trachomatis with macrolide and/or fluoroquinolone resistance would be uncommon, and azithromycin or fluoroquinolone regimens could be recommended as treatments for chlamydial infections.

'Haemophilus quentini' in the urethra of men complaining of urethritis symptoms.

We isolated a cryptic genospecies of Haemophilus influenzae referred to as 'Haemophilus quentini' in the urethra of 3 men complaining of urethritis symptoms. H. influenzae strains, which had been isolated from the urethra in 77 of 1518 men complaining of urethritis symptoms, identified by the conventional test, and stored, were re-cultured for this study. Sixty-seven strains surviving storage were screened by a PCR-based assay specific for the cryptic genital Haemophilus genospecies. Three strains (HI09003, HI11006, and HI14016) were screened by PCR and identified as 'H. quentini' by 16S rRNA sequencing. The men positive for HI09003 and HI11006 were diagnosed as having non-chlamydial non-gonococcal urethritis (NGU), and their demographic and clinical features were similar to those of NGU caused by other pathogens. The man positive for HI14016 was ultimately diagnosed as having condyloma acuminatum on the glans. The 3 strains of 'H. quentini' produced no ß-lactamase and were susceptible to ampicillin and other antimicrobial agents, including cephalosporins, fluoroquinolones, tetracyclines, and macrolides, recommended for treatment for urethritis. 'H. quentini' would be an uncommon pathogen in men with urogenital infections. Based on the clinical features of the two patients with 'H. quentini'-positive NGU, it would be difficult to predict the presence of 'H. quentini' in the urethra. The 3 strains of 'H. quentini' were susceptible to a variety of antimicrobial agents. Further accumulation of data regarding 'H. quentini' infections is needed to characterize the pathogenic roles of this genospecies in urogenital infections and to establish appropriate management of 'H. quentini' infections.

GyrA and/or ParC alterations of Haemophilus influenzae strains isolated from the urethra of men with acute urethritis.

Of 73 clinical strains of Haemophilus influenzae isolated from the urethra of men with urogenital infections, we enrolled 6 strains (8.2%) with levofloxacin (LVFX) minimum inhibitory concentrations (MICs) of ≥0.03 µg/ml in this study. All the strains were isolated from non-gonococcal urethritis (NGU). We amplified the quinolone resistance-determining region of the gyrA gene and the analogous region of the parC gene from bacterial DNAs by PCR and sequenced the PCR products. Two strains with a LVFX MIC of 0.03 µg/ml had an amino acid change of Asp88 to Gly in GyrA. One with a LVFX MIC of 0.06 µg/ml had a change of Asp88 to Tyr in GyrA. Two with respective LVFX MICs of 0.12 and 0.25 µg/ml had a change of Ser84 to Leu in GyrA. One with a LVFX MIC of 1 µg/ml had changes of Ser84 to Leu in GyrA and of Ser84 to Ile in ParC. Multilocus sequence typing showed two strains with a change of Asp88 to Gly in GyrA had the same sequence type, but the others had sequence types different from each other. Single amino acid changes in GyrA alone or single changes in both GyrA and ParC could contribute to decreased susceptibility to fluoroquinolones in H. influenzae isolates from NGU. Most of the isolates with GyrA and/or ParC alterations would be multiclonal. The prevalence of such isolates would be relatively low, and they would still be susceptible to fluoroquinolones commonly prescribed for treatment of NGU.

Antimicrobial susceptibility of Haemophilus influenzae strains isolated from the urethra of men with acute urethritis and/or epididymitis.

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 ß-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 ß-lactamase-nonproducing ampicillin-resistant strains from acute urethritis and/or epididymitis appeared to be lower, but that of ß-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.

Haemophilus influenzae Isolated From Men With Acute Urethritis: Its Pathogenic Roles, Responses to Antimicrobial Chemotherapies, and Antimicrobial Susceptibilities.

BACKGROUND: There have been few comprehensive studies on Haemophilus influenza-positive urethritis. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.

Antimicrobial Susceptibility of Neisseria gonorrhoeae in Japan from 2000 to 2015.

BACKGROUND: Gonococcal infections are difficult to treat because of their multidrug antimicrobial resistance. The outbreak of antimicrobial-resistant Neisseria gonorrhoeae has begun in Asia and particularly in Japan. Therefore, it is very important that we understand the trend of antimicrobial resistance of N. gonorrhoeae in Asia including Japan. Our surveillance of the antimicrobial susceptibility of N. gonorrhoeae began in 2000 under the guidance of the Department of Urology, Gifu University. We report our surveillance data from 2000 to 2015. METHODS: We collected N. gonorrhoeae strains isolated from patients with gonococcal infections who visited our cooperating medical institutions in Japan from 2000 to 2015. MICs of penicillin G, cefixime, ceftriaxone, tetracycline, spectinomycin, azithromycin, and levofloxacin were determined by the agar dilution method approved by the Clinical and Laboratory Standards Institute. RESULTS: From 2000 to 2015, 2471 isolates of N. gonorrhoeae were collected in Japan. High rates of nonsusceptibility to penicillin, tetracycline, levofloxacin, cefixime, and azithromycin were shown. Around 5% to 10% of the strains isolated had a 0.25-mg/L MIC of ceftriaxone in each year, and 6 strains (0.24%) with a 0.5-mg/L MIC of ceftriaxone were isolated throughout the study period. Approximately 5% to 10% of the strains were resistant to each of ceftriaxone, azithromycin, and levofloxacin according to European Committee on Antimicrobial Susceptibility Testing breakpoints, and the rate has not increased significantly. CONCLUSIONS: From this study and previous pharmacodynamic analyses, a single 1-g dose of ceftriaxone is recommended to treat gonorrhea. As strains with high-level ceftriaxone resistance continue to spread, higher doses of ceftriaxone in monotherapy or multiple doses of ceftriaxone should be considered.

Remarkable increase of Neisseria gonorrhoeae with decreased susceptibility of azithromycin and increase in the failure of azithromycin therapy in male gonococcal urethritis in Sendai in 2015.

The antimicrobial resistance of Neisseria gonorrhoeae is a serious problem worldwide. In this study, we examined the susceptibility of N. gonorrhoeae isolated from male gonococcal urethritis in Sendai in 2014 and 2015. Furthermore, of all cases, we investigated the clinical efficacy of a single 2-g dose of extended-release azithromycin (AZM-SR) in the treatment of male gonococcal urethritis retrospectively. Sixty N. gonorrhoeae strains in 2014 and 54 strains in 2015 were isolated from male gonococcal urethritis and stored each year. The MIC of AZM was ≥1 mg/L in 4 strains (6.7%) in 2014 and in 13 strains (24.1%) in 2015 and the number of strains having ≥1 mg/L MIC increased significantly (P = 0.016). Microbiological efficacy was evaluated in 32 and 29 of these patients, and the rates of treatment success were 93.8% and 79.3%, respectively. All of the treatment failures were caused by strains having a MIC of AZM of ≥0.5 mg/L. In particular, the increase in the isolates having a MIC of AZM of ≥1 mg/L was remarkable. Therefore, it was thought that the increase in these strains was the reason for the increase in treatment failures in 2015. Because no other drug is effective, it is currently necessary to use AZM-SR to treat gonococcal infections caused by ceftriaxone-resistant strains or patients allergic to ceftriaxone. To prevent a further increase in resistance to AZM, we should not use AZM-SR to treat normal cases of gonococcal infection.

Microbiological efficacy and tolerability of a single-dose regimen of 1 g of ceftriaxone in men with gonococcal urethritis.

OBJECTIVES: We treated men with gonococcal urethritis with a single-dose regimen of 1 g of ceftriaxone, which is recommended as the first-line treatment for gonorrhoea in Japan, to determine its microbiological outcomes and tolerability. METHODS: We enrolled 255 men with gonococcal urethritis and treated them with a single-dose regimen of 1 g of ceftriaxone. We evaluated its microbiological outcomes and tolerability. We also determined ceftriaxone MICs for pretreatment isolates of Neisseria gonorrhoeae collected from the patients. RESULTS: The microbiological efficacy of the ceftriaxone regimen, which was determined between 5 and 9 days after treatment in 111 men based on the Japanese guideline for clinical research on antimicrobial agents in urogenital infections, was 100%. In the 194 men who returned to the clinic between 2 and 41 days after treatment, 191 (98.5%; 95% CI 96.8%-100%) were negative for N. gonorrhoeae after treatment. Ceftriaxone MICs determined for 136 pretreatment isolates obtained from these 194 men ranged from 0.001 to 0.25 mg/L. One isolate persisting after treatment exhibited a ceftriaxone MIC of 0.008 mg/L. For two isolates persisting after treatment, ceftriaxone MICs were not determined. Seven adverse events were observed in 7 (3.2%) of the 220 men treated with the ceftriaxone regimen. Four men had diarrhoea classified as grade 1. Three had urticaria during ceftriaxone administration, with one event classified as grade 1 and two events classified as grade 3. CONCLUSIONS: A single-dose regimen of 1 g of ceftriaxone was microbiologically effective against gonococcal urethritis and was safe and tolerable.

Novel penA mutations identified in Neisseria gonorrhoeae with decreased susceptibility to ceftriaxone isolated between 2000 and 2014 in Japan.

OBJECTIVES: We examined four clinical strains of Neisseria gonorrhoeae (GU030113, GU110095, GU110332 and GU110362) isolated between 2000 and 2014 in Japan, exhibiting ceftriaxone MICs of 0.5 mg/L, for mutations of the genes associated with penicillin resistance. METHODS: The penA, mtrR, porB1b (penB), ponA and pilQ genes of the strains were sequenced. PBP2s of the strains were aligned to the PBP2s associated with decreased susceptibility to oral cephalosporins, and PBP2s of previously reported strains with decreased susceptibility to ceftriaxone. RESULTS: GU030113 had PBP2 pattern X with an additional substitution of A502T. GU110095 had PBP2 pattern XXVII. GU110332 had PBP2 pattern XXXIV with an additional substitution of P552S. GU110362 had PBP2 composed of pattern X (amino acid positions 1-291) and pattern V (amino acid positions 292-576). GU030113, GU110095 and GU110332 had deletion of A in the mtrR promoter, G120K and A121D or A121N in PorB1b and L421P in PBP1. GU110362 had A40D in the repressor of MtrR and L421P in PBP1. The strains did not have mutations of pilQ1 and pilQ2. CONCLUSIONS: Addition of A502T to PBP2 pattern X in GU030113 and of P552S to PBP2 pattern XXXIV in GU110332 would possibly contribute to decreased susceptibility to ceftriaxone. In GU110095 and GU110362, it was suggested that, in addition to their altered PBP2s, the enhanced efflux pump, reduced permeability in the outer membrane, another altered target of ß-lactams and/or other mechanisms not identified in the present study might contribute to decreased susceptibility.

Remarkable increase in fluoroquinolone-resistant Mycoplasma genitalium in Japan.

OBJECTIVES: We determined the prevalence of macrolide and fluoroquinolone resistance-associated mutations in Mycoplasma genitalium DNA specimens from men with non-gonococcal urethritis (NGU) and analysed their effects on antibiotic treatments of M. genitalium infections. METHODS: In this retrospective study, we examined antibiotic resistance-associated mutations in the 23S rRNA, gyrA and parC genes of M. genitalium and the association of the mutations with microbiological outcomes of antibiotic treatments in men with M. genitalium-positive NGU. RESULTS: No macrolide resistance-associated mutations in the 23S rRNA gene were observed in 27 M. genitalium DNA specimens in 2011 and in 24 in 2012. However, 5 of 17 in 2013 had 23S rRNA mutations. Three of 15 in 2011, 6 of 19 in 2012 and 8 of 17 in 2013 had fluoroquinolone resistance-associated alterations in ParC. Three in 2013 had both the antibiotic resistance-associated alterations coincidentally. In two men with M. genitalium harbouring 23S rRNA mutations, the mycoplasma persisted after treatment with a regimen of 2 g of extended-release azithromycin (AZM-SR) once daily for 1 day. All nine men with mycoplasma harbouring ParC alterations were microbiologically cured with a regimen of 100 mg of sitafloxacin twice daily for 7 days. CONCLUSIONS: Macrolide- or fluoroquinolone-resistant M. genitalium appears to be increasing, and the increase in fluoroquinolone-resistant mycoplasmas is especially remarkable in Japan. Mycoplasmas harbouring 23S rRNA mutations would be resistant to the AZM-SR regimen, but those harbouring ParC alterations would still be susceptible to the sitafloxacin regimen.