Tomohiro Tsuchiya

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.

Bacterial loads of Ureaplasma urealyticum contribute to development of urethritis in men.

Ureaplasma urealyticum could be a pathogen of non-gonococcal urethritis (NGU) in men. However, ureaplasma is often detected in men without NGU, and the proportion of cases possibly attributable to this pathogen is still undefined. We attempted to determine the bacterial loads of U. urealyticum significantly associated with NGU. The 16S rRNA genes of U. urealyticum were quantified by a real-time polymerase chain reaction-based assay in first-void urine (FVU) from 26 asymptomatic and 25 symptomatic men positive for U. urealyticum. The leucocyte counts in first-void urine (FVU) were determined as an objective measure of inflammatory response to ureaplasma in the hosts by automated quantitative urine particle analysis. Positive correlations were observed between copies of the 16S rRNA genes of U. urealyticum per ml and the leucocyte counts per µl in FVU (r = 0.49, p = 0.0003). Loads of ≥104 copies of the 16S rRNA gene of U. urealyticum/ml, corresponding to ≥5 × 103 cells of U. urealyticum/ml in FVU, were significantly associated with the presence of urethritis symptoms (p < 0.0001) and with higher leukocyte counts in FVU (p < 0.0001). The bacterial load of U. urealyticum, possibly of ≥5 × 103 cells of U. urealyticum/ml in FVU, could be significantly associated with the development of symptomatic NGU.

Prevalence of genital mycoplasmas and ureaplasmas in men younger than 40 years-of-age with acute epididymitis

Objectives:  Acute epididymitis is often associated with urethritis. Mycoplasma genitalium and Ureaplasma urealyticum have been considered as pathogens of urethritis. The aim of the present study was to determine the prevalence of these microorganisms in men with acute epididymitis.

Male non-gonococcal urethritis: From microbiological etiologies to demographic and clinical features.

To detect microorganisms responsible for male acute urethritis and to define the microbiology of non‐gonococcal urethritis.

Bilateral primary malignant lymphoma of the ureter.

We report the case of a 68-year-old Japanese man who presented with postrenal azotemia due to bilateral upper ureteral stenosis. The patients right kidney was nonfunctional; therefore, right nephroureterectomy was performed for the purpose of pathologic diagnosis. Histopathologic examination revealed follicular lymphoma with diffuse change in the ureter. With chemotherapy for malignant lymphoma, the stenosis of the left ureter was alleviated, and left renal function was preserved. Primary malignant lymphoma of the ureter is extremely rare. In cases of ureteral stenosis with ureteral wall thickening for which the cause is uncertain, the possibility of malignant lymphoma of the ureter should be considered.

Drug Resistance-Associated Mutations in Mycoplasma genitalium in Female Sex Workers, Japan

Mycoplasma genitalium was detected in 21 (14.1%) of 149 vaginal swab samples and in 1 (0.7%) of 149 throat washing samples from female sex workers during 2013–2014 in Japan. Prevalences of M. genitalium with macrolide resistance–associated 23S rRNA mutations and fluoroquinolone resistance–associated parC alterations were 47.1% and 36.8%, respectively.

Bacterial loads of Ureaplasma parvum contribute to the development of inflammatory responses in the male urethra

Ureaplasma parvum, which has been recognised as a coloniser in the male urethra, is detected in some men with non-gonococcal urethritis. In this study, we quantified the 16 S rRNA genes of U. parvum by a real-time polymerase chain reaction-based assay in first-voided urine from 15 symptomatic and 38 asymptomatic men who were positive only for U. parvum. We also determined the leukocyte counts by automated quantitative urine particle analysis in their first-voided urine. Positive correlations were observed between copies of the 16 S rRNA genes of U. parvum/ml and the leukocyte counts/µl in first-voided urine (p = 0.0019). The loads of ≥104 copies of the 16 S rRNA gene/ml, corresponding to ≥5 × 103 cells of U. parvum/ml, were significantly associated with the presence of ≥12.5 leukocytes/µl in first-voided urine that might document the presence of inflammatory responses in the urethra. However, a large portion of the subjects (83.0%) had bacterial loads of <5 × 103 cells of U. parvum/ml, and 79.5% of them showed <12.5 leukocytes/µl. The ambiguity of the pathogenic role of U. parvum in non-gonococcal urethritis could, in part, be due to its low bacterial loads, which might not give rise to inflammatory responses in the male urethra.

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 β-lactams and/or other mechanisms not identified in the present study might contribute to decreased susceptibility.

Prediction of the persistence of Mycoplasma genitalium after antimicrobial chemotherapy by quantification of leukocytes in first-void urine from patients with non-gonococcal urethritis

Mycoplasma genitalium is regarded as another pathogen of male non-gonococcal urethritis (NGU). Failure to eradicate this mycoplasma is associated with persistent or recurrent NGU, but this mycoplasma is not routinely examined in clinical practice. In cases of M. genitalium-positive NGU, therefore, some criteria are needed to assess the success or failure of antimicrobial chemotherapy other than microbiological outcomes. We enrolled 49 men with M. genitalium-positive non-chlamydial NGU. At successive visits after treatment, we inquired about their symptoms, observed their urethral meatus for urethral discharge, and examined their first-void urine (FVU) for quantification of leukocytes and for the persistence of M. genitalium. M. genitalium was eradicated in 34 patients after treatment, whereas the mycoplasma persisted in 15. Urethritis symptoms and urethral discharges were not found to be predictors of the persistence of M. genitalium up to the 25th day after the start of treatment. Leukocyte counts in FVU from the patients with persistence of M. genitalium were significantly higher than those from the patients with eradication of the mycoplasma. Leukocyte counts of 10 leukocytes/μl or more between the 18th and 24th day after the start of treatment were most significantly associated with the persistence of M. genitalium. Quantification of leukocytes in FVU would appear to be crucial to judge the outcome of treatment in patients with non-chlamydial NGU and could be helpful to predict the persistence of M. genitalium after treatment when M. genitalium is not routinely examined in clinical specimens in clinical practice.

Effect of Conversion From Twice-daily to Once-daily Tacrolimus on Glucose Intolerance in Stable Kidney Transplant Recipients

BACKGROUND Tacrolimus is an established immunosuppressant for the prevention and treatment of allograft rejection in organ transplantation. However, tacrolimus therapy also has several adverse effects. The main aim of this study was to evaluate the effect of conversion from twice-daily tacrolimus (tacrolimus-BID) to once-daily tacrolimus (tacrolimus-OD) on glucose intolerance in stable kidney transplant patients. METHODS The study comprised 43 kidney transplant recipients with stable renal function. The same 1 mg:1 mg dose conversion was used for all patients. Follow-up, which included clinical evaluation and laboratory testing, was performed at 30, 60, and 120 days after conversion. The parameters for which the baseline and end-point values were determined included homeostasis model assessment of beta-cell function (HOMA-B) scores, hemoglobin A(1c) (HbA(1c)) levels, serum insulin levels, and fasting glucose levels. RESULTS The tacrolimus trough levels did not differ significantly at 120 days after conversion. There was a significant increase in serum insulin level at 120 days after conversion (baseline, 5.6 ± 2.7 μU/mL; end point, 6.6 ± 3.4 μU/mL; P < .009). The HOMA-B score slightly increased (baseline, 58.7 ± 33.1; end point, 65.6 ± 32.8; P = .091) at 120 days after conversion, indicating beta-cell function. Serum creatinine concentration, blood glucose level, and HbA(1c) level did not change significantly during follow-up examinations. Episodes of acute rejection or graft loss did not occur. CONCLUSION The results of this study suggests that conversion from tacrolimus-BID to tacrolimus-OD may benefit kidney transplant patients with glucose intolerance because of improved insulin secretion. Further studies involving a larger sample population and longer follow-up time are required to verify the results of this study.