Vaginosis Bacteriana – Actualización y novedad terapéutica

La vaginosis bacteriana es la causa del flujo vaginal anormal más común en mujeres en edad reproductiva. Esta patología se presenta en la mayoría de los casos de forma asintomática y cuenta con una alta tasa de recurrencia. Desde la perspectiva fisiopatológica, la vaginosis bacteriana se causa por un desequilibrio bacteriano vaginal. Este desequilibro genera un desplazamiento de la flora vaginal normal y como consecuencia ésta se coloniza principalmente por bacterias anaerobias como: Gardenerella vaginalis, Prevotella, Peptostreptoccocus, Ureaplasma urealyticum, porphyromonas y mycoplasma hominis. Las pacientes pueden presentar clínicamente un flujo blanquecino o grisáceo, en ocasiones espumoso que puede ser mal oliente. Estas pacientes aparte de la clínica o sintomatología genital también podrían presentar un estrés psicológico que podría llevar al desarrollo de patologías de índole psiquiátrica. El tratamiento de la patología se realiza con antibióticos, de primera elección, dentro de los cuales se encuentra el metronidazol o clindamicina vaginal u oral y como segunda línea se utiliza el tinidazol o el secnidazol, ambos por vía oral. De igual forma, recientemente se han desarrollado nuevas terapias que ayudan a evitar el alto porcentaje de recurrencia de la patología, como colonias de Lactobaciillus depositadas directamente en la vagina.

In silico and in vitro analysis of recombinant arginine deiminase from Pseudomonas furukawaii as a potential anticancer enzyme

Arginine deiminase (ADI) is a promising anticancer enzyme that can be employed in amino acid deprivation therapy for the treatment of various arginine auxotrophic tumors. In our previous work, Pseudomonas furukawaii was identified as a potent producer of ADI with optimum activity at physiological pH and temperature. The 3D structure of PfADI was modeled. Immunoinformatics analysis was also carried out to compare the immunogenicity of PfADI with MhADI (Mycoplasma hominis ADI, which is in phase III clinical trials). The PfADI was found to be less immunogenic in terms of number of linear and conformational B cell epitopes and T cell epitope density. The overall antigenicity and allergenicity of PfADI was also lower as compared to MhADI. Thus, the ADI coding arcA gene was cloned and expressed in E. coli BL21. Recombinant ADI of P. furukawaii (PfADI) was purified using affinity chromatography and its molecular mass was estimated to be ~46KDa. PfADI was found to effectively inhibit the HepG2 cells with an IC50 value of 0.1950 IU/ml. PfADI was characterized and the enzyme was found to be stable at human physiological conditions (pH 7 and 37 ⁰C temperature). The Km and Vmax values were found to be 1.90 mM and 1.83 µmol ml-1min-1 respectively. Thus the present in vitro and in silico studies establish PfADI as a potential anticancer drug candidate with improved efficacy and low immunogenicity.

Laboratory diagnostics of urogenital mycoplasma colonization and infection

The paper presents data on the possibilities of determining urogenital mycoplasmas (Mycoplasma hominis and Ureaplasma urealyticum) using some variants of culture and PCR methods. The scheme of cultural studies in full is given, with the help of which high specificity and sensitivity indicators are achieved. The proposed research algorithm for detecting Mycoplasma hominis and Ureaplasma urealyticum, based on the use of culture and PCR methods as complementary.

Sequence analysis reveals asymptomatic infection with Mycoplasma hominis and Ureaplasma urealyticum possibly leads to infertility in females: A cross-sectional study

Background: Genetic evidence of asymptomatic Mycoplasma hominis (M. hominis) and Ureaplasma urealyticum (U. urealyticum) infection associated with infertility among females is lacking because suitable high throughput molecular methods have not been applied. Objective: This study aimed to explore the occurrence of M. hominis and U. urealyticum in the genital tract of females with asymptomatic infection and infertility as well as determine their genetic relatedness. Materials and Methods: The study group included 100 asymptomatic females and 31 females diagnosed with infertility. Sequencing of the 16S rRNA gene following DNA extraction was performed directly from endo-cervical swabs. Phylogenetic analysis established the genetic linkage between the isolates from both groups. Results: In asymptomatic females, M. hominis and U. urealyticum were detected with a prevalence of 8% and 2% respectively. Among females with infertility, the prevalence was 6.45% and 3.23% for M. hominis and U. urealyticum respectively. In both groups, M. hominis occurred significantly more frequently. Phylogenetic analysis revealed three distinct clusters in both groups: two with already characterized M. hominis and Ureaplasma species (28.6% of the overall Mycoplasma spp.) and one distinct cluster matched with U. urealyticum. Furthermore, all M. hominis from asymptomatic females clustered significantly with infertility contrary to U. urealyticum. The M. hominis cluster was significantly linked to two strains from China. Conclusion: The sequence analysis of Mycoplasma and Ureaplasma in the genital tract of asymptomatic and infertile females showed significant association; therefore, it is paramount to consider them as possible etiologic agents of infertility and genital infection, especially when the etiology of infertility is unknown. Key words: Mycoplasma hominis, Ureaplasma urealyticum, Genetic linkage, Asymptomatic infections, Infertility.

Postoperative mediastinitis after cardiac surgery caused by Mycoplasma hominis: a case report

Background Mycoplasma hominis is a human commensal bacterium of the urogenital tract, and extragenital infection caused by M. hominis has rarely been reported. The identification of M. hominis is challenging, and surgeons are generally not aware that this bacteria can cause postoperative infection. Here, we report a rare case of postoperative mediastinitis caused by M. hominis after cardiac surgery in an immunocompetent patient. Case presentation A 54-year-old man presented with pain and purulent discharge from the wound after aortic valve replacement and patent foramen ovale closure. However, Gram staining and culture of bacteria from the purulent discharge was negative, and empiric sulbactam/ampicillin therapy was not effective. This patient developed mediastinitis and rupture of a pseudoaneurysm of the ascending aorta caused by mediastinitis, and re-operation was performed. Then, postoperative mediastinitis caused by M. hominis or Ureaplasma species was suspected and bacterial cultures targeting these pathogens were performed. M. hominis was identified from abscess and tissue obtained from the surgical site and urine. A final diagnosis of postoperative mediastinitis caused by M. hominis was determined. The patient was initially treated with levofloxacin and then with minocycline for 3 weeks. The patient’s clinical condition improved; the patient was transferred to another hospital. Conclusion The role of M. hominis as a cause of postoperative infection might be underestimated in cardiac surgery. M. hominis should be considered when culture-negative purulent discharge is observed or there is no response to standard empiric treatment of postoperative infections.

Defining Fluoroquinolone Resistance-Mediating Mutations from Non-Resistance Polymorphisms in Mycoplasma hominis Topoisomerases

Often dismissed as a commensal, Mycoplasma hominis is an increasingly prominent target of research due to its role in septic arthritis and organ transplant failure in immunosuppressed patients, particularly lung transplantation. As a mollicute, its highly reductive genome and structure render it refractile to most forms of treatment and growing levels of resistance to the few sources of treatment left, such as fluoroquinolones. We examined antimicrobial susceptibility (AST) to fluoroquinolones on 72 isolates and observed resistance in three (4.1%), with corresponding mutations in the quinolone resistance-determining region (QRDR) of S83L or E87G in gyrA and S81I or E85V in parC. However, there were high levels of polymorphism identified between all isolates outside of the QRDR, indicating caution for a genomics-led approach for resistance screening, particularly as we observed a further two quinolone-susceptible isolates solely containing gyrA mutation S83L. However, both isolates spontaneously developed a second spontaneous E85K parC mutation and resistance following prolonged incubation in 4 mg/L levofloxacin for an extra 24–48 h. Continued AST surveillance and investigation is required to understand how gyrA QRDR mutations predispose M. hominis to rapid spontaneous mutation and fluoroquinolone resistance, absent from other susceptible isolates. The unusually high prevalence of polymorphisms in M. hominis also warrants increased genomics’ surveillance.

Therapeutic Drug Monitoring of Moxifloxacin to Guide Treatment of Mycoplasma hominis Meningitis in an Extremely Preterm Infant

Mycoplasma hominis (M hominis) is a rare cause of neonatal bacterial meningitis. Treatment can be challenging because of M hominis' intrinsic antibiotic resistance and the difficulty in accessing antimicrobial susceptibility testing. In this report, we describe an extremely preterm male infant with seizures who had a subsequent diagnosis of M hominis meningitis. Because of severity of illness, doxycycline (4 mg/kg IV every 24 hours) and moxifloxacin (5 mg/kg IV every 24 hours) were started empirically. Repeat cerebrospinal fluid cultures were negative and showed decreasing pleiocytosis. Given the concentration-dependent killing of moxifloxacin and concern for endovascular infection from a concomitant cerebral venous sinus thrombosis, serum concentrations of moxifloxacin were obtained to estimate pharmacokinetic and pharmacodynamic parameters. These were compared to the targets described in other case reports of M hominis meningitis. The maximum serum concentration (Cmax) was 2.5 mg/L, volume of distribution was 2.2 L/kg, clearance was 0.18 L/kg/hr, terminal half-life was 8.6 hours, and area-under-the-concentration-time curve (AUC) was 28.1 mg•hr/L. Using the range of minimum inhibitory concentrations (MICs) reported in the literature, the estimated Cmax/MIC for this patient was 21 to 158 (target Cmax/MIC: >10) and AUC/MIC was 234 to 1757 (target AUC/MIC: ≥100). Doxycycline and moxifloxacin were continued for 6 weeks. No adverse events to moxifloxacin or doxycycline were observed in the NICU. This report describes the successful treatment of M hominis neonatal meningitis and adds to the knowledge of pharmacokinetic and pharmacodynamic parameters of moxifloxacin in neonates. Additional data will help to confirm the role for routine therapeutic drug monitoring of moxifloxacin in neonates.

Determination of In Vitro Antimicrobial Susceptibility for Lefamulin (Pleuromutilin) for Ureaplasma Spp. and Mycoplasma hominis

Lefamulin is the first of the pleuromutilin class of antimicrobials to be available for therapeutic use in humans. Minimum inhibitory concentrations of lefamulin were determined by microbroth dilution for 90 characterised clinical isolates (25 Ureaplasma parvum, 25 Ureaplasma urealyticum, and 40 Mycoplasma hominis). All Mycoplasma hominis isolates possessed lefamulin MICs of ≤0.25 mg/L after 48 h (MIC50/90 of 0.06/0.12 mg/L), despite an inherent resistance to macrolides; while Ureaplasma isolates had MICs of ≤2 mg/L after 24 h (MIC50/90 of 0.25/1 mg/L), despite inherent resistance to clindamycin. Two U. urealyticum isolates with additional A2058G mutations of 23S rRNA, and one U. parvum isolate with a R66Q67 deletion (all of which had a combined resistance to macrolides and clindamycin) only showed a 2-fold increase in lefamulin MIC (1–2 mg/L) relative to macrolide-susceptible strains. Lefamulin could be an effective alternative antimicrobial for treating Ureaplasma spp. and Mycoplasma hominis infections irrespective of intrinsic or acquired resistance to macrolides, lincosamides, and ketolides. Based on this potent in vitro activity and the known good, rapid, and homogenous tissue penetration of female and male urogenital tissues and glands, further exploration of clinical efficacy of lefamulin for the treatment of Mycoplasma and Ureaplasma urogenital infections is warranted.

Mycoplasma genitalium and Mycoplasma hominis infection in south Korea during 2018-2020

Background and Objectives: Sexually transmitted infections (STIs) can remain undetected and untreated; therefore, rapid diagnosis and treatment of STIs are important. Mycoplasma genitalium (MG), Mycoplasma hominis (MH), and Ureaplasma urealyticum are sexually transmitted pathogens that cause asymptomatic, organ-specific, and chronic infections, thereby pos- ing a threat to community health. Therefore, we investigated the epidemiological trends of MG and MH infections in South Korea for rapid diagnosis and treatment. Materials and Methods: From September 2018 to December 2020, samples (catheter, pus, tissue, swab, and urine) were collected from outpatients of hospitals in South Korea for molecular biological venereal disease testing. DNA was extracted and analyzed using real-time polymerase chain reaction. Results: Of the 59,381 samples analyzed, 8.78% (n=5,215) were positive for MG and MH. The MH positivity rate (5.51%, n=3,273) was higher than the MG positivity rate (3.27%, n=1,942). MG and MH positivity rates were the highest in patients aged <19 years. Men had higher MG positivity rate, whereas women had higher MH positivity rates. Furthermore, the MG- positivity rate was the highest in the swab samples of both men and women, whereas that of MH was the highest in the urine samples of men and swab samples of women. Conclusion: We identified the differences between MG and MH positivity rates based on sex, specimen, and age. Our findings can provide information for strategies that protect public health and reduce STI incidence and transmission.