Genomic determination of minimum multi-locus sequence typing schemas to represent the genomic phylogeny of Mycoplasma hominis

An overview regarding the relationship between Mollicutes, infertility and antibiotic resistance (Review)

Throughout the past decades, physicians have increasingly conferred regarding the role of Mollicutes in infertility in both male and female patients. Although Ureaplasma and Mycoplasma do not represent a leading cause of infertility, whether dermatovenerologists, gynecologists and urologists should not disregard them when screening patients with infertility problems is discussed in the present review. While these infections are completely asymptomatic in ~80% of cases, they do lead to both chronic inflammation of the genital tract and reproductive disorders. Different Mollicute strains and/or serovars, genomic traits and proteomic markers have been examined in order to understand not only the exact mechanism by which they cause infertility, but also their relationship with the worldwide spreading resistance to antibiotics. The current review provided an overview of the latest studies regarding the new findings on the relationship between Mollicutes, infertility and antibiotic resistance. Awareness should be raised among clinicians to screen sexually active adults wishing to conceive who have failed to achieve a pregnancy; in addition, an antibiogram should be performed and treatment should be carried out according to the guidelines.

The prevalence of gonococcal and non-gonococcal infections in women referred to obstetrics and gynecology clinics

Bacterial vaginosis is a condition caused by changes in the vaginal microbial ecosystem and increases the risk of preterm delivery, premature rupture of membranes, endometritis, and weight loss of the baby. This study aimed to evaluate the frequency of gonococcal and non-gonococcal genital infections in women referred to clinics in Ilam, Iran. Two swab samples were taken from each patient using a sterile swab, one swab was placed in a THB medium for the culture of Streptococcus agalactiae and the other in PBS buffer for PCR. PCR method was conducted for the identification of the other bacterial agents such as Neisseria gonorrhoeae, Chlamydia trachomatis, Mycoplasma genitalium, Mycoplasma hominis, Ureaplasma urealyticum, and also S. agalactiae. Sampling was performed on 169 women with symptomatic vaginosis. The frequency of S. agalactiae by culture and PCR methods was 4.7% (8 samples) and 13.6% (23 samples) respectively. Also, 6.5% (11 samples), 3.5% (6 samples), 4.1% (7 samples), 1.2% (2 samples), and 0% of the samples were positive for N. gonorrhoeae, M. genitalium, M. hominis, U. urealyticum and C. trachomatis by PCR method. Except for a significant association between S. agalactiae colonization and abortion, there was no significant correlation between the prevalence of these bacteria and the patient's age, age of marriage, number of deliveries, and number of abortions. Overall, the prevalence of gonococcal and non-gonococcal infection in women referred to clinics in Ilam is similar to the other parts of Iran.

minMLST: machine learning for optimization of bacterial strain typing

MOTIVATION

High-resolution microbial strain typing is essential for various clinical purposes, including disease outbreak investigation, tracking of microbial transmission events and epidemiological surveillance of bacterial infections. The widely used approach for multilocus sequence typing (MLST) that is based on the core genome, cgMLST, has the advantage of a high level of typeability and maximal discriminatory power. Yet, the transition from a seven loci-based scheme to cgMLST involves several challenges, that include the need by some users to maintain backward compatibility, growing difficulties in the day-to-day communication within the microbiology community with respect to nomenclature and ontology, issues with typeability, especially if a more stringent approach to loci presence is used, and computational requirements concerning laboratory data management and sharing with end-users. Hence, methods for optimizing cgMLST schemes through careful reduction of the number of loci are expected to be beneficial for practical needs in different settings.

RESULTS

We present a new machine learning-based methodology, minMLST, for minimizing the number of genes in cgMLST schemes by identifying subsets of informative genes and analyzing the trade-off between gene reduction and typing performance. The results achieved with minMLST over eight bacterial species show that despite the reduction in the number of genes up to a factor of 10, the typing performance remains very high and significant with an Adjusted Rand Index that ranges between 0.4 and 0.93 in different species and a P-value < 10-3. The identification of such optimized MLST schemes for bacterial strain typing is expected to improve the implementation of cgMLST by improving interlaboratory agreement and communication.

AVAILABILITY AND IMPLEMENTATION

The python package minMLST is available at https://PyPi.org/project/minmlst/PyPI and supported on Linux and Windows.

SUPPLEMENTARY INFORMATION

Supplementary data are available at Bioinformatics online.

Tetracycline Resistance Mediated by tet(M) Has Variable Integrative Conjugative Element Composition in Mycoplasma hominis Strains Isolated in the United Kingdom from 2005 to 2015

A minimal genome and absent bacterial cell wall render Mycoplasma hominis inherently resistant to most antimicrobials except lincosamides, tetracyclines, and fluoroquinolones. Often dismissed as a commensal (except where linked to preterm birth), it causes septic arthritis in immunodeficient patients and is increasingly associated with transplant failure (particularly lung) accompanying immunosuppression. We examined antimicrobial susceptibility (AST) on strains archived from 2005 to 2015 submitted to the Public Health England reference laboratory and determined the underlying mechanism of resistance by whole-genome sequencing (WGS). Archived M. hominis strains included 32/115 from invasive infection (sepsis, cerebrospinal [CSF], peritoneal, and pleural fluid) over the 10-year period (6.4% of all samples submitted from 2010 to 2015 were positive). No clindamycin resistance was detected, while two strains were resistant to moxifloxacin and levofloxacin (resistance mutations S83L or E87G in gyrA and S81I or E84V in parC). One of these strains and 11 additional strains were tetracycline resistant, mediated by tet(M) carried within an integrative conjugative element (ICE) consistently integrated at the somatic rumA gene; however, the ICEs varied widely in 5 to 19 associated accessory genes. WGS analysis showed that tet(M)-carrying strains were not clonal, refuting previous speculation that the ICE was broken and immobile. We found tet(M)-positive and -negative strains (including the multiresistant 2015 strain) to be equally susceptible to tigecycline and josamycin; however, the British National Formulary does not include guidance for these. Continued M. hominis investigation and AST surveillance (especially immunocompromised patients) is warranted, and the limited number of therapeutics needs to be expanded in the United Kingdom.

Epidemiology of genital infections caused by Mycoplasma hominis, M. genitalium and Ureaplasma urealyticum in Iran; a systematic review and meta-analysis study (2000-2019)

BACKGROUND

Although many species of mycoplasmas regard as normal flora, but some species causes serious genital disease. In Iran several epidemiological studies have documented the prevalence of Mycoplasma hominis, M. genitalium and Ureaplasma urealyticum in genital disorders. This meta-analysis is going to represent the prevalence of M. hominis, M. genitalium and U. urealyticum among Iranian couples and the correlation between mycoplasmas infection and infertility.

METHODS

We search online databases from January 2000 to June 2019. We used following MeSH keywords (Prevalence, M. hominis, M. genitalium, U. urealyticum, male, female, fertility, Infertility, genitourinary tract infection and Iran) with all possible combinations with "OR" and "AND". Finally, forty-four articles from 2670 were chosen for data extraction and analysis by software using STATA version 14.0.

RESULTS

This meta-analysis revealed that the prevalence of U. urealyticum was 17.53% in Iran and the prevalence of M. genitalium and M. hominis were 11.33 and 9.68% respectively. The rate of M. genitalium, M. hominis and U. urealyticum infection in women with symptoms of genitourinary tract infection was higher than men with genitourinary tract infection (6.46% vs 5.4, 7.67% vs 5.88 and 21.04% vs 12.13%, respectively). As expected, the prevalence of M. genitalium, U. urealyticum and M. hominis among infertile women (12.73, 19.58 and 10.81%) were higher than fertile women (3%, 10. 85% and 4. 35%). Similarly, the prevalence of M. hominis and U. urealyticum among infertile men (14 and 21.18%) were higher than fertile men (4 and 3%). Based on this analysis, the rate of U. urealyticum was higher than M. genitalium and M. hominis among infertile men and women compared to the fertile group. The prevalence rate of M. genitalium, M. hominis and U. urealyticum in central provinces is higher than other parts of Iran.

CONCLUSIONS

This meta-analysis reemphasizes a significant relationship between the infertility rate and U. urealyticum, M. genitalium and M. hominis infections. Our finding help to plan the prevalence map of M. hominis, M. genitalium and U. urealyticum in Iran but further studies are needed to suggest routine screening of the pathogens.

A novel approach for the identification and phylogenetic delineation of human Mycoplasma species and strains using genomic segment sequence analysis

Human Mycoplasma are opportunistic, facultative pathogens that are site-specific in their colonization of mucosal surfaces. They are responsible for significant annual morbidity in humans by causing acute illnesses and chronic auto-inflammatory diseases via modulation of the host's immune system. Accurate and reliable identification of Mycoplasma species and their strains are thus of upmost importance. This study, analysed for the first time, the effectiveness of a short (50 kb) genome fragment (termed as R-segment), which includes the complete rRNA operon and the flanking region up to 50 kb, as a single phylogenetic marker for assessing the molecular taxonomy and determining the identity of human Mycoplasma species and their strains. The R-segments of human mycoplasmas were shown to have inherent genetic properties [average nucleotide identity (ANI), codon bias index (CBI), genome-to-genome distances (GGD) and % G + C] similar to their whole genome counterparts. Based on the results of our R segment analysis, a species of human Mycoplasma can simply be defined as a group of strains that share R-segments with ANIs ≥97%. Additionally, R-segments offered superiority to 16S rRNA gene sequences and multilocus sequences for the delineation of the human Mycoplasma species and their strains. The overall comparative genomic results suggest that R-segment analysis can be considered as a promising cost-effective tool for the epidemiological surveillance and differentiation of the closely related species and/or strains of human mycoplasmas.

Phylogenetics of Mycoplasma hominis clinical strains associated with gynecological infections or infertility as disclosed by an expanded multilocus sequence typing scheme

To our knowledge, the phylodistribution of M. hominis clinical strains associated with various pathological conditions of the urogenital tract has not been explored hitherto. Here we analyzed the genetic diversity and phylogenetic relationships among 59 M. hominis Tunisian clinical isolates, categorized as gynecological infections- or infertility-associated pathotypes. For this purpose, we developed an expanded multilocus sequence typing (eMLST) scheme, combining the previously reported multilocus sequence typing (MLST) loci (gyrB, tuf, ftsY, uvrA, gap) with a new selected set of putative virulence genes (p120’, vaa, lmp1, lmp3, p60), referred herein to as multi-virulence-locus sequence typing (MVLST) loci. In doing so, M. hominis population was segregated into two distinct genetic lineages, which were differentially associated with each pathotype. Such a clear dichotomy was supported by several phylogenetic and population genetic analysis tools. Recombination was found to take place, but not sufficient enough to break down the overall clonal population structure of M. hominis, most likely as a result of purifying selection, which accommodated the most fit clones. In sum, and owing to the eMLST scheme described herein, we provide insightful data on the phylogenetics of M. hominis, arguing for the existence of genetically differentiable urogenital pathotypes.

Development of a highly sensitive PCR/DNA chip method to detect mycoplasmas in a veterinary modified live vaccine

Mycoplasmas are potential contaminants that introduce undesirable changes in mammalian cell cultures. They frequently contaminate cell substrates and other starting materials used for manufacturing cell-derived biologics, such as vaccines and pharmaceutical products. Mycoplasma purity testing of live vaccines, active ingredients, raw material, and seed lots is required during vaccine production. Previously, testing using a time-consuming, costly 28-day culture assay, which lacks sensitivity for species that do not grow in culture, was required in the European Pharmacopoeia (Ph. Eur). But now nucleic acid amplification techniques (NATs) can be used. NATs provide rapid results and are sensitive. We evaluated the sensitivity and specificity of a commercially-available NAT to detect individual mycoplasma DNA in a veterinary modified live vaccine using five reference strains recommended by the Ph. Eur. Our results showed that this NAT-based method can be used to detect mycoplasma in spiked live vaccine, without interference from the vaccine components, with a limit of detection of 10 CFU/mL, as required by the Ph. Eur. Its specificity was demonstrated since no mycoplasmas were detected in non-spiked vaccine. This method is undergoing validation as a replacement for the conventional culture method in the production of veterinary live vaccines.

Antimicrobial susceptibility, virulence potential and sequence types associated with Arcobacter strains recovered from human faeces

PURPOSE

The genus Arcobacter includes bacteria that are considered emergent pathogens because they can produce infections in humans and animals. The most common symptoms are bloody and non-bloody persistent diarrhea but cases with abdominal cramps without diarrhea or asymptomatic cases have also been described as well as cases with bacteremia. The objective was to characterize Arcobacter clinical strains isolated from the faeces of patients from three Spanish hospitals.

METHODOLOGY

We have characterized 28 clinical strains (27 of A. butzleri and one of A. cryaerophilus) isolated from faeces, analysing their epidemiological relationship using the multilocus sequence typing (MLST) approach and screening them for their antibiotic susceptibility and for the presence of virulence genes.Results/Key findings. Typing results showed that only one of the 28 identified sequence types (i.e. ST 2) was already present in the MLST database. The other 27 STs constituted new records because they included new alleles for five of the seven genes or new combinations of known alleles of the seven genes. All strains were positive for the ciaB virulence gene and sensitive to tetracycline. However, 7.4 % of the A. butzleri and A. cryaerophilus strains showed resistance to ciprofloxacin.

CONCLUSION

The fact that epidemiological unrelated strains show the same ST indicates that other techniques with higher resolution should be developed to effectively recognize the infection source. Resistance to ciprofloxacin, one of the antibiotics recommended for the treatment of Arcobacter intestinal infections, demonstrated in 10.7 % of the strains, indicates the importance of selecting the most appropriate effective treatment.