Sequence variation and immunogenicity of the Mycoplasma genitalium MgpB and MgpC adherence proteins during persistent infection of men with non-gonococcal urethritis

Detection of human IgG antibodies against Mycoplasma genitalium using a recombinant MG075 antigen

Mycoplasma genitalium is a sexually transmitted pathogen that can cause a range of reproductive tract diseases in both men and women. To disentangle the relationship between M. genitalium infection(s) and subsequent reproductive health complications at the population level, accurate serological tools are needed. The major challenge in developing specific M. genitalium serological tests is the extensive cross-reactivity with the closely related ubiquitous respiratory tract pathogen, Mycoplasma pneumoniae. In this report, we describe the development of an immunoblot assay based on a recombinant fragment of the M. genitalium MG075 protein present in lipid-associated membrane extracts. A sensitivity of 87.1% was achieved based on the testing antibody responses in sera from 101 adults with PCR-confirmed M. genitalium infection. A specificity of 95.2% was obtained through the evaluation of sera from 166 children under 15 years of age with and without M. pneumoniae infection, who were unlikely to have been exposed to sexually transmitted M. genitalium. The development of a serological assay capable of accurately distinguishing M. genitalium and M. pneumoniae will enable a better understanding of associations between M. genitalium and adverse reproductive sequelae.

IMPORTANCE

Mycoplasma genitalium is the second most common sexually transmitted bacterial infection after chlamydia. The long-term consequences of the infection are still under investigation, but reliable tools for monitoring exposure by detection of antibodies have been lacking specificity due to the presence of cross-reacting antibodies to the closely related Mycoplasma pneumoniae. Here, we describe a novel diagnostic antigen with promising sensitivity (87%) and specificity (95%) based on testing of sera from patients with PCR-confirmed M. genitalium infection and children with and without M. pneumoniae infection, respectively. The MG075F1 antigen was expressed in Escherichia coli, and the recombinant antigen was used in a western line-blot. Due to the insolubility of the antigen, harsh denaturing conditions were needed, making an enzyme-linked immunosorbent assay (ELISA) format impossible. Future work should explore shorter fragments or protein engineering to allow for assay designs better suited for high-throughput screening.

Detection of human IgG antibodies against Mycoplasma genitalium using a recombinant MG075 antigen

Mycoplasma genitalium is a sexually transmitted pathogen, which can cause a range of reproductive tract diseases in both men and women. To disentangle the relationship between M. genitalium infection(s) and subsequent reproductive health complications at the population level, accurate serological tools are needed. The major challenge in developing specific M. genitalium serological tests is the extensive cross-reactivity with the closely related ubiquitous respiratory tract pathogen, M. pneumoniae. In this report, we describe the development of an immunoblot assay based on a recombinant fragment of the M. genitalium MG075 protein present in lipid-associated membrane extracts. A sensitivity of 87.1% was achieved based on testing antibody responses in sera from 101 adults with PCR-confirmed M. genitalium infection. A specificity of 95.2% was obtained through evaluation of sera from 166 children under 15 years of age with and without M. pneumoniae infection, who were unlikely to have been exposed to sexually transmitted M. genitalium. The development of a serological assay capable of accurately distinguishing M. genitalium and M. pneumoniae, will enable a better understanding of associations between M. genitalium and adverse reproductive sequelae.

Rapid and visual detection of Mycoplasma genitalium using recombinase polymerase amplification combined with lateral flow strips

Mycoplasma genitalium (MG) is an important sexually transmitted pathogen that can cause urethritis in males and pelvic inflammatory disease in females. Due to its complex growth requirements and lengthy incubation times, culturing MG in clinical laboratories is impractical. Here we describe a rapid and visual assay combining recombinase polymerase amplification (RPA) with lateral flow (LF) strips to detect MG (MG-RPA-LF). The limit of detection (LoD) of this method was 33.6 genome equivalents (GE) per reaction, using a dilution series of purified genomic DNA. Clinical performance was evaluated by testing 100 urogenital swabs. Compared to the Simultaneous Amplification and Testing assay, our MG-RPA-LF assay showed a sensitivity of 94 % (95 % CI, 82 %-98 %) and a specificity of 100 % (95 % CI, 91 %-100 %). The overall concordance between the two methods was 97 % (95 % CI, 91 %-99 %) with a κ coefficient of 0.94 (P < 0.001). Without cumbersome and expensive instruments, this method is anticipated to be a promising alternative to diagnose MG infection, especially in resource-poor settings.

Mycoplasma genitalium in the US (MyGeniUS): Surveillance Data From Sexual Health Clinics in 4 US Regions

BACKGROUND

Mycoplasma genitalium (MG) is on the CDC Watch List of Antimicrobial Resistance Threats, yet there is no systematic surveillance to monitor change.

METHODS

We initiated surveillance in sexual health clinics in 6 cities, selecting a quota sample of urogenital specimens tested for gonorrhea and/or chlamydia. We abstracted patient data from medical records and detected MG and macrolide-resistance mutations (MRMs) by nucleic acid amplification testing. We used Poisson regression to estimate adjusted prevalence ratios (aPRs) and 95% CIs, adjusting for sampling criteria (site, birth sex, symptom status).

RESULTS

From October-December 2020 we tested 1743 urogenital specimens: 57.0% from males, 46.1% from non-Hispanic Black persons, and 43.8% from symptomatic patients. MG prevalence was 16.6% (95% CI: 14.9-18.5%; site-specific range: 9.9-23.5%) and higher in St Louis (aPR: 1.9; 1.27-2.85), Greensboro (aPR: 1.8; 1.18-2.79), and Denver (aPR: 1.7; 1.12-2.44) than Seattle. Prevalence was highest in persons <18 years (30.4%) and declined 3% per each additional year of age (aPR: .97; .955-.982). MG was detected in 26.8%, 21.1%, 11.8%, and 15.4% of urethritis, vaginitis, cervicitis, and pelvic inflammatory disease (PID), respectively. It was present in 9% of asymptomatic males and 15.4% of asymptomatic females, and associated with male urethritis (aPR: 1.7; 1.22-2.50) and chlamydia (aPR: 1.7; 1.13-2.53). MRM prevalence was 59.1% (95% CI: 53.1-64.8%; site-specific range: 51.3-70.6%). MRMs were associated with vaginitis (aPR: 1.8; 1.14-2.85), cervicitis (aPR: 3.5; 1.69-7.30), and PID cervicitis (aPR: 1.8; 1.09-3.08).

CONCLUSIONS

MG infection is common in persons at high risk of sexually transmitted infections; testing symptomatic patients would facilitate appropriate therapy. Macrolide resistance is high and azithromycin should not be used without resistance testing.

Serum and Urethral Antibody Response in Mycoplasma genitalium -Infected Men

ABSTRACT

The antibody response to Mycoplasma genitalium in serum and urethral secretions of men with nongonococcal urethritis was examined longitudinally. Serum and urethral antibodies reacted primarily with the MgpB and MgpC adhesins. Serum antibodies persisted throughout follow-up, whereas urethral antibodies waned despite organism persistence. Declining antibodies may facilitate chronic infection.

Genotyping of Mycoplasma pneumoniae strains isolated in Japan during 2019 and 2020: spread of p1 gene type 2c and 2j variant strains

We characterized 118 Mycoplasma pneumoniae strains isolated from three areas of Japan (Saitama, Kanagawa, and Osaka) during the period of 2019 and 2020. Genotyping of the p1 gene in these strains revealed that 29 of them were type 1 lineage (29/118, 24.6%), while 89 were type 2 lineage (89/118, 75.4%), thereby indicating that type 2 lineage was dominant in this period. The most prevalent variant of type 2 lineage was type 2c (57/89, 64%), while the second-most was type 2j, a novel variant identified in this study (30/89, 33.7%). Type 2j p1 is similar to type 2 g p1, but cannot be distinguished from reference type 2 (classical type 2) using the standard polymerase chain reaction-restriction fragment length polymorphism analysis (PCR-RFLP) with HaeIII digestion. Thus, we used MboI digestion in the PCR-RFLP analysis and re-examined the data from previous genotyping studies as well. This revealed that most strains reported as classical type 2 after 2010 in our studies were actually type 2j. The revised genotyping data showed that the type 2c and 2j strains have been spreading in recent years and were the most prevalent variants in Japan during the time-period of 2019 and 2020. We also analyzed the macrolide-resistance (MR) mutations in the 118 strains. MR mutations in the 23S rRNA gene were detected in 29 of these strains (29/118, 24.6%). The MR rate of type 1 lineage (14/29, 48.3%) was still higher than that of type 2 lineage (15/89, 16.9%); however, the MR rate of type 1 lineage was lower than that found in previous reports published in the 2010s, while that of type 2 lineage strains was slightly higher. Thus, there is a need for continuous surveillance of the p1 genotype and MR rate of M. pneumoniae clinical strains, to better understand the epidemiology and variant evolution of this pathogen, although M. pneumoniae pneumonia cases have decreased significantly since the COVID-19 pandemic.

Update in Epidemiology and Management of Mycoplasma genitalium Infections

Mycoplasma genitalium is a frequent cause of urogenital syndromes in men and women and is associated with adverse sequelae in women. M genitalium also infects the rectum, and may cause proctitis, but rarely infects the pharynx. Diagnosis requires nucleic acid amplification testing. Antibiotic resistance is widespread: more than half of infections are resistant to macrolides and fluoroquinolone resistance is increasing. Resistance-guided therapy is recommended for symptomatic patients, involving initial treatment with doxycycline to reduce organism load followed by azithromycin for macrolide-sensitive infections or moxifloxacin for macrolide-resistant infections. Neither screening nor tests of cure are recommended in asymptomatic persons.

Pathogenicity and virulence of Mycoplasma genitalium: Unraveling Ariadne's Thread

Mycoplasma genitalium, a pathogen from class Mollicutes, has been linked to sexually transmitted diseases and sparked widespread concern. To adapt to its environment, M. genitalium has evolved specific adhesins and motility mechanisms that allow it to adhere to and invade various eukaryotic cells, thereby causing severe damage to the cells. Even though traditional exotoxins have not been identified, secreted nucleases or membrane lipoproteins have been shown to cause cell death and inflammatory injury in M. genitalium infection. However, as both innate and adaptive immune responses are important for controlling infection, the immune responses that develop upon infection do not necessarily eliminate the organism completely. Antigenic variation, detoxifying enzymes, immunoglobulins, neutrophil extracellular trap-degrading enzymes, cell invasion, and biofilm formation are important factors that help the pathogen overcome the host defence and cause chronic infections in susceptible individuals. Furthermore, M. genitalium can increase the susceptibility to several sexually transmitted pathogens, which significantly complicates the persistence and chronicity of M. genitalium infection. This review aimed to discuss the virulence factors of M. genitalium to shed light on its complex pathogenicity and pathogenesis of the infection.

mgpB genotyping and genetic diversity for antimicrobial resistance of Mycoplasma genitalium

Introduction. Antimicrobial resistance (AMR) among Mycoplasma genitalium is a global issue. Understanding the transmission dynamics of infection is an important factor in reducing the occurrence of AMR.

Hypothesis/Gap Statement. There is limited information on the genotyping and AMR traits of M. genitalium .

Aims. Single-locus sequence-based (SLSB) mgpB sequence typing and genetic diversity analyses of AMR M. genitalium isolated from patients in the Republic of Korea were performed to clarify the transmission dynamics and eludicate proper management.

Methodology. Sanger sequencing of mgpB, 23S rRNA, parC and gyrA genes from a total of 103 M . genitalium -positive specimens from 89 patients was carried out.

Results. Twenty-seven different mgpB genotypes (GTs) were identified; 12 had been reported previously and 15 had not. GT7 and GT8 occurred frequently (n=38, 36.89 %, and n=16, 15.53 %, respectively). The genetic diversity of the AMR-determining sites was randomly dispersed among the different GTs. However, these GTs were classified into two phylogenetically distinct clusters that were significantly correlated with patient age and genetic diversity at positions 2058 and 2059 in the 23S rRNA gene. The GTs of 20 consecutive samples from 6 patients were compared to investigate temporal changes in GTs. One specimen changed its GT during follow-up, suggesting a new infection.

Conclusions. mgpB sequence typing can be a reliable tool for epidemiological studies. Two clusters have different characteristics in terms of genetic diversity. The cluster with genetic diversity in the AMR-determining site may be explained by the high prevalence of the specimens and subsequent antimicrobial exposure during the study period.

Molecular Tools for Typing Mycoplasma pneumoniae and Mycoplasma genitalium

Mycoplasma pneumoniae and Mycoplasma genitalium are cell wall-less bacteria with strongly reduced genome content and close phylogenetic relatedness. In humans, the only known natural host, the microorganisms colonize the respiratory or genitourinary mucosa and may cause a broad range of clinical presentations. Besides fundamental differences in their tissue specificity, transmission route, and ability to cause prevalence peaks, both species share similarities such as the occurrence of asymptomatic carriers, preferred populations for infection, and problems with high rates of antimicrobial resistance. To further understand the epidemiology of these practically challenging bacteria, typing of strains is necessary. Since the cultivation of both pathogens is difficult and not performed outside of specialized laboratories, molecular typing methods with adequate discriminatory power, stability, and reproducibility have been developed. These include the characterization of genes containing repetitive sequences, of variable genome regions without the presence of repetitive sequences, determination of single and multi-locus variable-number tandem repeats, and detection of single nucleotide polymorphisms in different genes, respectively. The current repertoire of procedures allows reliable differentiation of strains circulating in different populations and in different time periods as well as comparison of strains occurring subsequently in individual patients. In this review, the methods for typing M. pneumoniae and M. genitalium, including the results of their application in different studies, are summarized and current knowledge regarding the association of typing data with the clinical characteristics of infections is presented.

Mycoplasmas as Host Pantropic and Specific Pathogens: Clinical Implications, Gene Transfer, Virulence Factors, and Future Perspectives

Mycoplasmas as economically important and pantropic pathogens can cause similar clinical diseases in different hosts by eluding host defense and establishing their niches despite their limited metabolic capacities. Besides, enormous undiscovered virulence has a fundamental role in the pathogenesis of pathogenic mycoplasmas. On the other hand, they are host-specific pathogens with some highly pathogenic members that can colonize a vast number of habitats. Reshuffling mycoplasmas genetic information and evolving rapidly is a way to avoid their host's immune system. However, currently, only a few control measures exist against some mycoplasmosis which are far from satisfaction. This review aimed to provide an updated insight into the state of mycoplasmas as pathogens by summarizing and analyzing the comprehensive progress, current challenge, and future perspectives of mycoplasmas. It covers clinical implications of mycoplasmas in humans and domestic and wild animals, virulence-related factors, the process of gene transfer and its crucial prospects, the current application and future perspectives of nanotechnology for diagnosing and curing mycoplasmosis, Mycoplasma vaccination, and protective immunity. Several questions remain unanswered and are recommended to pay close attention to. The findings would be helpful to develop new strategies for basic and applied research on mycoplasmas and facilitate the control of mycoplasmosis for humans and various species of animals.

Molecular epidemiology and antimicrobials resistance mechanism of Mycoplasma genitlaium

Currently, infections caused by Mycoplasma genitalium are ones the most common sexually transmitted infections. Their prevalence is varied from 1.3% to 15.9%. Infections caused by M.genitalium may lead to urethritis in men and a wide spectrum of diseases in women. Antibiotic resistance now is one of the most emerging problems both in the scientific and in the healthcare fields. The usage of antimicrobials inhibiting cell wall synthesis for the treatment of M.genitalium is ineffective, and resistance to macrolides and fluoroquinolones is increasing rapidly. M.genitalium infections diagnostics is complicated due to specific conditions and duration of culture methods. The usage of nucleic acid amplification techniques is the most relevant for laboratory diagnostics, and is used in existing assays. This review compiles current data on the prevalence, molecular mechanisms of pathogenesis and antibiotic resistance, as well as diagnostics methods of M.genitalium.

The Sialoglycan Binding Adhesins of Mycoplasma genitalium and Mycoplasma pneumoniae

Mycoplasma genitalium (Mge) and Mycoplasma pneumoniae (Mpn) are two human pathogens associated with urogenital and respiratory tract infections, respectively. The recent elucidation of the tridimensional structure of their major cytoadhesins by X-ray crystallography and cryo-electron microscopy/tomography, has provided important insights regarding the mechanics of infection and evasion of immune surveillance.