We report a case of Mycoplasma hominis ventriculitis in a preterm neonate that was successfully identified with 16S ribosomal RNA sequencing and whole genome sequencing after failure to detect the ...pathogen with conventional diagnostic methods. The infant required doxycycline with subsequent clearance of the infection and no evidence of drug toxicity.
Trichomonas vaginalis is an anaerobic protist, responsible for the most prevalent non-viral sexually transmitted infection in humans. One of the most intriguing aspects of T. vaginalis pathobiology ...is the complex relationship with intracellular microbial symbionts: a group of dsRNA viruses belonging to family of Totiviridae (T. vaginalis virus), and eubacteria belonging to the Mycoplasma genus, in particular Mycoplasma hominis. Both microorganisms seem to strongly influence the lifestyle of T. vaginalis, suggesting a role of the symbiosis in the high variability of clinical presentation and sequelae during trichomoniasis. In the last few years many aspects of this unique symbiotic relationship have been investigated: M. hominis resides and replicates in the protozoan cell, and T. vaginalis is able to pass the bacterial infection to both mycoplasma-free protozoan isolates and human epithelial cells; M. hominis synergistically upregulates the proinflammatory response of human monocytes to T. vaginalis. Furthermore, the influence of M. hominis over T. vaginalis metabolism and physiology has been characterized. The identification of a novel species belonging to the class of Mollicutes (Candidatus Mycoplasma girerdii) exclusively associated to T. vaginalis opens new perspectives in the research of the complex series of events taking place in the multifaceted world of the vaginal microbiota, both under normal and pathological conditions.
Mycoplasma hominis is an opportunistic human pathogen, associated with clinically diverse disease. Currently, there is no standardised method for typing M. hominis, which would aid in understanding ...pathogen epidemiology and transmission. Due to availability and costs of whole genome sequencing and the challenges in obtaining adequate M. hominis DNA, the use of whole genome sequence analysis to provide clinical guidance is unpractical for this bacterial species as well as other fastidious organisms.
This study identified pan-genome set of 700 genes found to be present in four published reference genomes. A subset of 417 genes was identified to be core genome for 18 isolates and 1 reference. Leave-one-out analysis of the core genes highlighted set of 48 genes that are required to recapture the original phylogenetic relationships observed using whole genome SNP analysis. Three 7-locus MLST schemas with high diversity index (97%) and low dN/dS ratios (0.1, 0.13, and 0.11) were derived that could be used to confer good discrimination between strains and could be of practical use in future studies direct on clinical specimens.
The genes proposed in this study could be utilised to design a cost-effective and rapid PCR-based MLST assay that could be applied directly to clinical isolates, without prior isolation. This study includes additional genomic analysis revealing high levels of genetic heterogeneity among this species. This provides a novel and evidence based approach for the development of MLST schema that accurately represent genomic phylogeny for use in epidemiology and transmission studies.
This study investigated the prevalence and antibiotic resistance of Ureaplasma spp. and Mycoplasma hominis isolated from asymptomatic individuals in Korea. Endocervical swabs from women and urine ...from men, from a total of 5,781 asymptomatic individuals, were analyzed using a Mycoplasma IST2 Kit. Of the 4,825 specimens tested from females, 486 (10.1%) were positive culture. In these positive specimens, 437 (9.1%) were positive only for Ureaplasma spp., 17 (0.4%) were positive only for M. hominis, and 32 (0.7%) were positive for both Ureaplasma spp. and M. hominis. In males, of the 956 tested specimens, only 4 (0.42%) were positive for Ureaplasma spp. and no M. hominis colonization was identified. In antimicrobial susceptibility tests, more than 93.2% of both M. hominis and Ureaplasma spp. was susceptible to tetracycline, doxycycline, josamycin, and pristinamycin. However, M. hominis isolates were found to be highly resistant to erythromycin, azithromycin, and clarithromycin (82.4%, 70.6%, and 76.5%, respectively). Ofloxacin and ciprofloxacin, which have recently exhibited increasing resistance rates, showed rates of 17.7% and 35.3%, respectively, in M. hominis, and 50.6% and 27.4%, respectively, in Ureaplasma spp. In conclusion, accurate antimicrobial susceptibility tests of the genital mycoplasmas should be conducted for each case to select the appropriate antibiotics. Fluoroquinolone-based drugs should be avoided in the initial treatment of urogenital mycoplasmas because of the increasing rate of resistance to quinolones, although the susceptibility to tetracycline remains high in Korea.
Trichomonas vaginalis is the causative agent of trichomoniasis, one of the most common sexually transmitted diseases worldwide. In recent years we have described the symbiotic relationship between T ...vaginalis and Mycoplasma hominis. How this biological association might affect the pathogenicity of one or both the microorganisms is still unknown. Since local inflammation is thought to play a central role in T vaginalis infection, we investigated the in vitro response of human macrophages to naturally mycoplasma-free T vaginalis, as compared to a mycoplasma-infected trichomonad isolate.
THP-1 cells were stimulated with two isogenic T vaginalis isolates, one naturally mycoplasma-free and one stably associated with M hominis, and secreted cytokines measured by ELISA. Nuclear factor κB (NFκB) involvement in THP-1 response to T vaginalis and M hominis was evaluated by means of a reporter system based on detection of alkaline phosphatase activity.
We found that the presence of M hominis upregulates the expression of a panel of proinflammatory cytokines in a synergistic fashion. We also found that the upregulation of the proinflammatory response by THP-1 cells involves the transcription factor NFκB.
These findings suggest that the presence of M hominis in T vaginalis isolates might play a key role in inflammation during trichomoniasis, thus affecting the severity of the disease. The synergistic upregulation of the macrophage proinflammatory response might also affect some important clinical conditions associated with T vaginalis infection, such as the increased risk of acquiring cervical cancer or HIV, which are thought to be affected by the inflammatory milieu during trichomoniasis.
Background. Bacterial vaginosis (BV) is a poorly detected public health problem that is associated with preterm delivery and for which no reliable diagnostic tool exists. Methods. Molecular analysis ...of 231 vaginal samples, classified by Gram stain–based Nugent score, was used to propose molecular criteria for BV; these criteria were prospectively applied to 56 new samples. A quantitative molecular tool targeting 8 BV-related microorganisms and a human gene was developed using a specific real-time polymerase chain reaction assay and serial dilutions of a plasmid suspension. The targeted microorganisms were Gardnerella vaginalis, Lactobacillus species, Mobiluncus curtisii, Mobiluncus mulieris, and Candida albicans (which can be identified by Gram staining), as well as Atopobium vaginae, Mycoplasma hominis, and Ureaplasma urealyticum (which cannot be detected by Gram staining). Results. With use of the Nugent score, 167 samples were classified as normal, 20 were classified as BV, and 44 were classified as intermediate. Except for U. urealyticum, M. mulieris, and Lactobacillus species, DNA of the tested bacteria was detected more frequently in samples demonstrating BV, but the predictive value of such detection was low. The molecular quantification of A. vaginae (DNA level, ⩾108 copies/mL) and G. vaginalis (DNA level, ⩾109 copies/mL) had the highest predictive value for the diagnosis of BV, with excellent sensitivity (95%), specificity (99%), and positive (95%) and negative (99%) predictive values; 25 (57%) of the samples demonstrating intermediate flora had a BV profile. When applied prospectively, our molecular criteria had total positive and negative predictive values of 96% and 99%, respectively. Conclusions. We report a highly reproducible, quantitative tool to objectively analyze vaginal flora that uses cutoff values for the concentrations of A. vaginae and G. vaginalis to establish the molecular diagnosis of BV.
Mycoplasma spp. are rarely recognized agents of infective endocarditis. We report a case of Mycoplasma hominis prosthetic valve endocarditis diagnosed by 16S ribosomal DNA (rDNA) PCR and culture of ...valves in a 74-year-old man. We reviewed the literature and found only 8 other cases reported.
Mycoplasma hominis was isolated in 1937 from the human genital tract, followed 17 years later by Ureaplasma urealyticum and 27 years after that by Mycoplasma genitalium. The first two proved ...relatively easy to culture but the latter required a polymerase chain reaction assay for further studies. In sexually mature women, M. hominis may be found in the vagina/cervix of about 20–50%, ureaplasmas in 40–80% and M. genitalium in 0–5%. Some heterogeneity has been found among strains of all these species, sufficient to divide ureaplasmas into two species, namely U. urealyticum and Ureaplasma parvum. Studies in female mice show that sex hormones have a profound influence on colonization, multiplication and persistence of mycoplasmas/ureaplasmas in the genital tract and provoke the question, unanswered, of whether there is such an effect in the human tract. In women, there is no evidence that any of the mycoplasmal species stimulate an inflammatory vaginitis. M. hominis organisms increase hugely in number in the case of bacterial vaginosis (BV), and to a lesser extent so do ureaplasmas. Despite this, they have not been incriminated as a sole cause of BV. Evidence for the involvement of M. genitalium remains controversial. The strong association of BV with preterm birth raises the possibility that the genital mycoplasmas might play a part, but assurance that any do will be difficult to obtain. Detailed examination of the vaginal microbiome has not yet provided an answer.
Genital mycoplasmas colonise up to 80% of sexually mature women and may invade the amniotic cavity during pregnancy and cause complications. Tetracyclines and fluoroquinolones are contraindicated in ...pregnancy and erythromycin is often used to treat patients. However, increasing resistance to common antimicrobial agents is widely reported. The purpose of this study was to investigate antimicrobial susceptibility patterns of genital mycoplasmas in pregnant women.
Self-collected vaginal swabs were obtained from 96 pregnant women attending an antenatal clinic in Gauteng, South Africa. Specimens were screened with the Mycofast Revolution assay for the presence of Ureaplasma species and Mycoplasma hominis. The antimicrobial susceptibility to levofloxacin, moxifloxacin, erythromycin, clindamycin and tetracycline were determined at various breakpoints. A multiplex polymerase chain reaction assay was used to speciate Ureaplasma positive specimens as either U. parvum or U. urealyticum.
Seventy-six percent (73/96) of specimens contained Ureaplasma spp., while 39.7% (29/73) of Ureaplasma positive specimens were also positive for M. hominis. Susceptibilities of Ureaplasma spp. to levofloxacin and moxifloxacin were 59% (26/44) and 98% (43/44) respectively. Mixed isolates (Ureaplasma species and M. hominis) were highly resistant to erythromycin and tetracycline (both 97% resistance). Resistance of Ureaplasma spp. to erythromycin was 80% (35/44) and tetracycline resistance was detected in 73% (32/44) of Ureaplasma spp. Speciation indicated that U. parvum was the predominant Ureaplasma spp. conferring antimicrobial resistance.
Treatment options for genital mycoplasma infections are becoming limited. More elaborative studies are needed to elucidate the diverse antimicrobial susceptibility patterns found in this study when compared to similar studies. To prevent complications in pregnant women, the foetus and the neonate, routine screening for the presence of genital mycoplasmas is recommended. In addition, it is recommended that antimicrobial susceptibility patterns are determined.
(
) belongs to the class
, characterized by a very small genome size, reduction of metabolic pathways, including transcription factors, and the absence of a cell wall. Despite this, they adapt well ...not only to specific niches within the host organism but can also spread throughout the body, colonizing various organs and tissues. The adaptation mechanisms of
, as well as their regulatory pathways, are poorly understood. It is known that, when adapting to adverse conditions,
can undergo phenotypic switches that may persist for several generations.
To investigate the adaptive properties of
related to survival in the host, we conducted a comparative phenotypic and proteogenomic analysis of eight clinical isolates of
obtained from patients with urogenital infections and the laboratory strain H-34.
We have shown that clinical isolates differ in phenotypic features from the laboratory strain, form biofilms more effectively and show resistance to ofloxacin. The comparative proteogenomic analysis revealed that, unlike the laboratory strain, the clinical isolates possess several features related to stress survival: they switch carbon metabolism, activating the energetically least advantageous pathway of nucleoside utilization, which allows slowing down cellular processes and transitioning to a starvation state; they reconfigure the repertoire of membrane proteins; they have integrative conjugative elements in their genomes, which are key mediators of horizontal gene transfer. The upregulation of the methylating subunit of the restriction-modification (RM) system type I and the additional components of RM systems found in clinical isolates suggest that DNA methylation may play a role in regulating the adaptation mechanisms of
in the host organism. It has been shown that based on the proteogenomic profile, namely the genome sequence, protein content, composition of the RM systems and additional subunits HsdM, HsdS and HsdR, composition and number of transposable elements, as well as the sequence of the main variable antigen Vaa, we can divide clinical isolates into two phenotypes: typical colonies (TC), which have a high growth rate, and atypical (aTC) mini-colonies, which have a slow growth rate and exhibit properties similar to persisters.
We believe that the key mechanism of adaptation of
in the host is phenotypic restructuring, leading to a slowing down cellular processes and the formation of small atypical colonies. This is due to a switch in carbon metabolism and activation the pathway of nucleoside utilization. We hypothesize that DNA methylation may play a role in regulating this switch.
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