Unraveling the adaptive strategies of Mycoplasma hominis through proteogenomic profiling of clinical isolates

Introduction

Mycoplasma hominis (M. hominis) belongs to the class Mollicutes, 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 M. hominis, as well as their regulatory pathways, are poorly understood. It is known that, when adapting to adverse conditions, Mycoplasmas can undergo phenotypic switches that may persist for several generations.

Methods

To investigate the adaptive properties of M. hominis related to survival in the host, we conducted a comparative phenotypic and proteogenomic analysis of eight clinical isolates of M. hominis obtained from patients with urogenital infections and the laboratory strain H-34.

Results

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 M. hominis 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.

Discussion

We believe that the key mechanism of adaptation of M. hominis 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.

Molecular Basis of the Slow Growth of Mycoplasma hominis on Different Energy Sources

Mycoplasma hominis is an opportunistic urogenital pathogen in vertebrates. It is a non-glycolytic species that produces energy via arginine degradation. Among genital mycoplasmas, M. hominis is the most commonly reported to play a role in systemic infections and can persist in the host for a long time. However, it is unclear how M. hominis proceeds under arginine limitation. The recent metabolic reconstruction of M. hominis has demonstrated its ability to catabolize deoxyribose phosphate to produce ATP. In this study, we cultivated M. hominis on two different energy sources (arginine and thymidine) and demonstrated the differences in growth rate, antibiotic sensitivity, and biofilm formation. Using label-free quantitative proteomics, we compared the proteome of M. hominis under these conditions. A total of 466 proteins were identified from M. hominis, representing approximately 85% of the predicted proteome, while the levels of 94 proteins changed significantly. As expected, we observed changes in the levels of metabolic enzymes. The energy source strongly affects the synthesis of enzymes related to RNA modifications and ribosome assembly. The translocation of lipoproteins and other membrane-associated proteins was also impaired. Our study, the first global characterization of the proteomic switching of M. hominis in arginine-deficiency media, illustrates energy source-dependent control of pathogenicity factors and can help to determine the mechanisms underlying the interaction between the growth rate and fitness of genome-reduced bacteria.

Computational prediction of Mycoplasma hominis proteins targeting in nucleus of host cell and their implication in prostate cancer etiology

Cancer has long been assumed to be a genetic disease. However, recent evidence supports the enigmatic connection of bacterial infection with the growth and development of various types of cancers. The cause and mechanism of the growth and development of prostate cancer due to Mycoplasma hominis remain unclear. Prostate cancer cells are infected and colonized by enteroinvasive M. hominis, which controls several factors that can affect prostate cancer growth in susceptible persons. We investigated M. hominis proteins targeting the nucleus of host cells and their implications in prostate cancer etiology. Many vital processes are controlled in the nucleus, where the proteins targeting M. hominis may have various potential implications. A total of 29/563 M. hominis proteins were predicted to target the nucleus of host cells. These include numerous proteins with the capability to alter normal growth activities. In conclusion, our results emphasize that various proteins of M. hominis targeted the nucleus of host cells and were involved in prostate cancer etiology through different mechanisms and strategies.

[Ribonucleolytic activity of mycoplasmas]

Mycoplasmas are incapable of de novo synthesis of nucleotides and must therefore secrete nucleases in order to replenish the pool of nucleic acid precursors. The nucleolytic activity of mycoplasmas is an important factor in their pathogenicity. Bacterial ribonucleases (RNases) may produce a broad spectrum of biological effects, including antiviral and antitumor activity. Mycoplasma RNases are therefore of interest. In the present work, capacity of Acholeplasma laidlawii and Mycoplasma hominis for RNase synthesis and secretion was studied. During the stationary growth phase, these organisms were found to synthesize Mg(2+)-dependent RNases, with their highest activity detected outside the cells. Localization of A. laidlawii RNases was determined: almost 90% of the RNase activity was found to be associated with the membrane vesicles. Bioinformational analysis revealed homology between the nucleotide sequences of 14 Bacillus subtilis genes encoding the products with RNase activity and the genes of the mycoplasmas under study. Amino acid sequences of 4 A. laidlawii proteins with ribonuclease activity and the Bsn RNase was also established.

[The adaptation of mycoplasmas to stress conditions: features of proteome shift in Mycoplasma hominis PG37 under starvation and low temperature]

Mycoplasma hominis--one of the widely spread mycoplasmas (class Mollicutes), associated with the socially significant human diseases and contamination of cell cultures. The solution of the problem on controlling M. hominis infections is connected with determination of the molecular basis, responsible for mechanisms of bacterium survival under unfavorable conditions. As a result of proteomic approach (2-DIGE and MALDI TOF/TOF MS) for the first time, 53 M. hominis PG37 proteins were detected, different abundance of which occurred at cultivating the bacterium under stress (starvation and low temperature) conditions. According to the classification of proteins by functional category (clusters of orthologous groups of proteins--COG), 47 of the 53 proteins of the mycoplasma are involved in the fundamental cellular and biochemical processes--translation (12; 22.64%), transcription (2; 3.77%), posttranslational modification (7; 13.20%), cell cycle control (2; 3.77%), energy production and conversion (6; 11.32%), carbohydrate transport and metabolism (3; 5.66%), amino acid transport and metabolism (8; 15.09%), nucleotide transport and metabolism (6; 11.32%), inorganic ion transport and metabolism (1; 1.89%). The functions of six proteins (11.32%) have not been found; 24 proteins (45.28%) are the factors of bacterium virulence. M. hominis PG37 proteins, the expression modulation of which arises under the unfavorable environmental conditions, are the components of adaptation mechanisms of the mycoplasma to the stressors and potential targets for controlling infections caused by this bacterium.

Life on arginine for Mycoplasma hominis: clues from its minimal genome and comparison with other human urogenital mycoplasmas

Mycoplasma hominis is an opportunistic human mycoplasma. Two other pathogenic human species, M. genitalium and Ureaplasma parvum, reside within the same natural niche as M. hominis: the urogenital tract. These three species have overlapping, but distinct, pathogenic roles. They have minimal genomes and, thus, reduced metabolic capabilities characterized by distinct energy-generating pathways. Analysis of the M. hominis PG21 genome sequence revealed that it is the second smallest genome among self-replicating free living organisms (665,445 bp, 537 coding sequences (CDSs)). Five clusters of genes were predicted to have undergone horizontal gene transfer (HGT) between M. hominis and the phylogenetically distant U. parvum species. We reconstructed M. hominis metabolic pathways from the predicted genes, with particular emphasis on energy-generating pathways. The Embden–Meyerhoff–Parnas pathway was incomplete, with a single enzyme absent. We identified the three proteins constituting the arginine dihydrolase pathway. This pathway was found essential to promote growth in vivo. The predicted presence of dimethylarginine dimethylaminohydrolase suggested that arginine catabolism is more complex than initially described. This enzyme may have been acquired by HGT from non-mollicute bacteria. Comparison of the three minimal mollicute genomes showed that 247 CDSs were common to all three genomes, whereas 220 CDSs were specific to M. hominis, 172 CDSs were specific to M. genitalium, and 280 CDSs were specific to U. parvum. Within these species-specific genes, two major sets of genes could be identified: one including genes involved in various energy-generating pathways, depending on the energy source used (glucose, urea, or arginine) and another involved in cytadherence and virulence. Therefore, a minimal mycoplasma cell, not including cytadherence and virulence-related genes, could be envisaged containing a core genome (247 genes), plus a set of genes required for providing energy. For M. hominis, this set would include 247+9 genes, resulting in a theoretical minimal genome of 256 genes.

Mycoplasma hominis, M. genitalium, and Ureaplasma parvum are human pathogenic bacteria that colonize the urogenital tract. They have minimal genomes, and thus have a minimal metabolic capacity. However, they have distinct energy-generating pathways and distinct pathogenic roles. We compared the genomes of these three human pathogen minimal species, providing further insight into the composition of hypothetical minimal gene sets needed for life. To this end, we sequenced the whole M. hominis genome and reconstructed its energy-generating pathways from gene predictions. Its unusual major energy-producing pathway through arginine hydrolysis was confirmed in both genome analyses and in vivo assays. Our findings suggest that M. hominis and U. parvum underwent genetic exchange, probably while sharing a common host. We proposed a set of genes likely to represent a minimal genome. For M. hominis, this minimal genome, not including cytadherence and virulence-related genes, can be defined comprising the 247 genes shared by the three minimal genital mollicutes, combined with a set of nine genes needed for energy production for cell metabolism. This study provides insight for the synthesis of artificial genomes.

[Localization of the division protein FtsZ in mycoplasma cells Mycoplasma hominis]

Localization of the protein FtsZ in Mycoplasma hominis cells was determined. Ultra thin sections were treated by rabbit polyclonal antibodies against FtsZ M. hominis: a conjugate of protein A with colloidal gold particles was used instead of secondary antibodies. Considerable polymorphism of cells was seen on electron microscopy pictures of M. hominis cells, which is typical for mycoplasmas. Among a wide variety of cell shapes we distinguished dumbbell-shaped dividing cells, and the cells connected with each other with the aid of thin membrane tubules (former constrictions). Dominants distribution of the label in the constriction area of dividing M. hominis cells and in the area of the thin membrane tubules was observed. We revealed the cross septum in the mycoplasma cells for the first time, as well as the gold labeling of this structure. Furthermore, in some rounded and oval cells colloidal gold particles labeled the whole plasma membrane in ring-shaped manner. Probably, the label in these cases marks a submembrane contractile ring (Z-ring). The facts mentioned above confirm that FtsZ of M. hominis plays an active role in the mycoplasma cytokinesis. In a series of cases spiral-like distribution of gold particles was observed. Probably, FtsZ protofilaments in M. hominis cells can form spiral structures similar to Z-spirals of Bacillus subtilis and Escherichia coli. Its presence in mycoplasma cells may be considered as an important argument in favour of model of Z-ring assembling through reorganization of Z-spirals. FtsZ also may participate in maintenance of mycoplasma cell shape (membrane localization).

Morphology of human Fallopian tubes after infection with Mycoplasma genitalium and Mycoplasma hominis--in vitro organ culture study

BACKGROUND

Female infertility can be caused by scarring and occlusion of the Fallopian tubes. Sexually transmitted bacteria can damage the delicate epithelial layer of human Fallopian tubes (HFT). Genital mycoplasmas are associated with human reproductive failure. Yet, there is not enough evidence that mycoplasmas can cause tubal factor infertility. We analysed the effects of infections with Mycoplasma hominis and Mycoplasma genitalium on the HFT epithelium and compared them with the effects of infections with genital pathogens: Chlamydia trachomatis and Neisseria gonorrhoeae.

METHODS

We used an in vitro model in which pieces of normal HFT were infected with different bacteria, and the outcome of the infections was analysed by scanning electron microscopy (SEM) and confocal microscopy.

RESULTS

The presence of M. hominis did not cause any morphological changes of the epithelium of HFT. Noticeable changes in the morphology of the ciliated cells were observed in M. genitalium-infected tissue. Five days post-infection, the cilia were abnormally swollen and some of the ciliated cells fell off the epithelium. These effects could be inhibited by pre-incubation of M. genitalium with antibody directed against the C-terminal part of the adhesion protein MgPa before infection of HFT organ culture.

CONCLUSION

We have shown that the presence of M. genitalium, but not M. hominis, in the HFT organ culture affected the epithelium and resulted in cilia damage. The effect of infection with M. genitalium on the HFT was, however, very moderate when compared with the extensive damage of the epithelium caused by N. gonorrhoeae or C. trachomatis.

Mycoplasma hominis attaches to and locates intracellularly in human spermatozoa

BACKGROUND

The study of sperm-mycoplasma interaction has been focused on the effects of infection on sperm quality, but few studies have reported the direct interaction of this bacterium with spermatozoa.

METHODS

Selected populations of viable, motile and infection-free human spermatozoa from three healthy men were incubated with 15-480 multiplicity of infection (MOI) units of DiIC18-labelled Mycoplasma hominis. Cells were analyzed by means of confocal microscopy and by the eosin-Y dye exclusion test between 10 min and 24 h post-infection.

RESULTS

As early as 10 min post-infection, clusters of M. hominis were seen attached to the sperm head, midpiece or tail. Mycoplasma showed an approximately 2.5-4.5-fold higher interaction with sperm head or tail than with midpiece. Sequential sectioning of infected spermatozoa revealed the intracellular location of M. hominis within cytosolic spaces of head and midpiece regions. A minor proportion of infected spermatozoa showed bent or coiled tails, and/or midpiece thickening. Sperm viability was not altered by M. hominis infection.

CONCLUSIONS

These results provide specific and conclusive evidence of M. hominis attachment and invasiveness towards human sperm cells, which seems not to affect their viability, suggesting that a short-term M. hominis interaction with spermatozoa results in non-apparent or subtle damage, but might have implications for long-term male or couple's fertility.

Long-term survival and intracellular replication of Mycoplasma hominis in Trichomonas vaginalis cells: potential role of the protozoon in transmitting bacterial infection

The existence of a symbiotic relationship between Trichomonas vaginalis and Mycoplasma hominis, which is the first reported example of symbiosis between two obligate human pathogens, has been recently reported by our research group. In this work, we examined the cellular location of M. hominis in respect to T. vaginalis. By using gentamicin protection assays, double immunofluorescence, and confocal microscopy, we obtained strong evidence that M. hominis is located within protozoan cells. 5-Bromodeoxyuridine incorporation assays showed that intracellularly located mycoplasmas actively synthesize DNA. Our results demonstrate that M. hominis has the capability of entering trichomonad cells and of replicating inside the protozoon. These findings suggest that symbiosis might provide the bacteria, during human infection, with the capability to resist to environmental stresses, such as host defense mechanisms and pharmacological therapies.

Increased expression of two multidrug transporter-like genes is associated with ethidium bromide and ciprofloxacin resistance in Mycoplasma hominis

Two genes, md1 and md2, coding for multidrug resistance ATP-binding cassette transporters were identified in Mycoplasma hominis PG21. Expression of these two genes, quantified by quantitative competitive reverse transcription-PCR, was significantly increased in ethidium bromide-resistant strains of M. hominis compared to that in M. hominis PG21.

Mycoplasma hominis septic arthritis in a pediatric renal transplant recipient: case report and review of the literature

Septic arthritis (SA) typically occurs in young children, often from Staphylococcus. With chronic immunosuppression, however, pathogens may be atypical. A 15-year-old African-American female developed Mycoplasma hominis SA in her right hip 2 months following cadaveric renal transplant (Tx). Her presentation was subtle and indolent, without fever or leukocytosis. Although reported in adult Tx recipients, M. hominis infections have not been described in pediatric recipients. Early immunosuppression (basiliximab, prednisone, tacrolimus, mycophenolate mofetil and Thymoglobulin) may have increased her susceptibility to M. hominis. Optimal therapy for M. hominis SA is not well established and relapses occur. This patient underwent joint incision and drainage, treatment for 8 weeks with doxycycline and levofloxacin guided by in vitro sensitivities, and a reduction in immunosuppression. She has been free of ongoing infection for 3 years with stable graft function (Cr 1.1 mg/dL) on moderate immunosuppression with prednisone, tacrolimus and MMF.

[Impact of Mycoplasma hominis and Ureaplasma urealyticum on the concentration of proinflammatory cytokines in vaginal fluid]

The main aim of this study was to determine impact of Mycoplasma hominis and Ureaplasma urealyticum on the concentrations of selected proinflammatory cytokines in vaginal fluid in pregnant women. The samples were obtained from 120 pregnant women at 22 to 36 weeks gestation. Vaginal fluid were analyzed for the concentrations of IL-1 alpha, IL-1 beta, IL-6 and IL-8 using standard enzyme-linked immunosorbent assay technique (ELISA), and cervical fluid for prevalence of Mycoplasma hominis and Ureaplasma urealyticum. Genital mycoplasmas were diagnosed in 36 of 120 pregnant women (30%), (in 17 of 36 women (47.2%) both M. hominis and U. urealyticum, in 14 women (38.9%) only U. urealyticum, and in 5 cases (13.8%) only M. hominis were diagnosed). Vaginal levels of IL-8 was statistically higher among women with genital mycoplasmas infection, as compared to group without these bacteria (p=0.033), while there was no correlation between IL-1 alpha, IL-1 beta and IL-6 concentrations and genital mycoplasmas infection. Future studies should concentrate on evaluation the impact of other lower genital tract bacteria on concentration of IL-8 and other proinflammatory cytokines.

Genital mycoplasmas in women attending a family planning clinic in Guiné-Bissau and their susceptibility to antimicrobial agents

A study on the prevalence of genital mycoplasmas and their susceptibility to the most common antimicrobial agents used for treating the infection was conducted on 94 women attending a family planning clinic in Guiné-Bissau. Fifty-four women (57.4%) were positive for Mycoplasma hominis and/or Ureaplasma urealyticum. M. hominis and U. urealyticum separately isolated from infected women yielded frequencies of 31.5 and 27.8%, respectively, the remainder were infected with both species. No strain was found to be resistant to all three commonly employed antibiotics for the management of these infections (erythromycin, tetracycline and ofloxacin), although multiple resistance to two antibiotics was frequent, especially when both genital mycoplasmas were present. Some 90.7 and 24.1% of all isolates were resistant to erythromycin and tetracycline, respectively. No resistance was observed to ofloxacin, although 50% of the strains had intermediate resistance. The high prevalence of genital mycoplasmas in women attending a family planning clinic in Guiné-Bissau, as demonstrated in this study, appears to be associated with trichomonosis and bacterial vaginosis. These infections were also found to be highly resistant to erythromycin and tetracycline and to have intermediate resistance to ofloxacin. However, further studies are necessary to establish the burden of infection due to antibiotic resistant genital mycoplasmas.

[Cloning and expression of the Mycoplasma hominis ftsZ for a cell division protein]

A Mycoplasma hominis chromosomal fragment containing the full-length ftsZ gene was cloned and sequenced. Natural expression of this gene was demonstrated by reverse transcription-polymerase chain reaction (RT-PCR) with total RNA. The M. hominis FtsZ protein was shown to differ substantially from its counterparts of two other Mycoplasma species, M. genitalium and M. pneumoniae. The possibility of M. hominis ftsZ expression in Escherichia coli was demonstrated with several bacterial strains. The M. hominis FtsZ protein was isolated from E. coli cells transformed with recombinant plasmids carrying the M. hominis ftsZ gene. Complementation between the E. coli and M. hominis FtsZ proteins was observed in transformants.

Drift of tetM determinant in urogenital microbiocenosis containing mycoplasmas during treatment with a tetracycline antibiotic

We studied the correlation between genetic transfer of tetM determinant in Tn916 conjugative transposon by urogenital mycoplasmas (Mycoplasma hominis and Ureaplasma urealyticum) and changes in the bacterial repertoire during treatment with a tetracycline antibiotic. Basic conditions favoring the nonspecific transfer of tetM determinant into mollicute cells are determined and the allele polymorphism of tetM determinant in clinical strains of M. hominis and U. urealyticum is evaluated. The structure of tetM gene in clinical mycoplasma and ureaplasma strains is characterized by a peculiar mosaic pattern and differs from all previously described alleles of this gene. The results suggest that tetracycline resistance in mollicutes is determined by mechanisms alternative to genetic transfer of tetM determinant.

Evidence of active efflux in resistance to ciprofloxacin and to ethidium bromide by Mycoplasma hominis

The uptake of fluoroquinolones was characterized for the fluoroquinolone-susceptible strain PG21 of Mycoplasma hominis. Accumulation of fluoroquinolones appeared to occur by passive diffusion. Addition of arginine as the energizer significantly reduced the uptake of fluoroquinolones, suggesting the presence of an energy-dependent efflux process. Reserpine and orthovanadate, two multidrug pump inhibitors, increased significantly the ciprofloxacin (CIP) uptake. In contrast, such a strong effect was not observed for moxifloxacin and pefloxacin uptakes. Two ethidium bromide (EtBr)-resistant strains, selected in vitro, showed a resistance profile compatible with a multidrug-resistant phenotype, with increased MICs for the hydrophilic fluoroquinolones, CIP and norfloxacin, EtBr, and acriflavine. Taking the EtBr-resistant strain RB1La as a model, a significant decrease of the CIP and EtBr uptakes was observed compared to the reference strain PG21. In the presence of reserpine and orthovanadate, both inhibitors of ATP-dependent efflux pumps, the CIP uptake increased significantly, reaching approximately the same level as that of the susceptible strain. Similar results were obtained with EtBr uptake and efflux experiments. Our data suggest the presence of an active efflux system, possibly an ABC-type efflux pump, implicated in the resistance to CIP and unrelated compounds like EtBr in the human mycoplasma M. hominis.

Coupled phase-variable expression and epitope masking of selective surface lipoproteins increase surface phenotypic diversity in Mycoplasma hominis

A new mechanism expanding mycoplasmal surface diversity is described. Exposure of surface epitopes on a constitutively expressed membrane protein (P56) of Mycoplasma hominis was subject to high-frequency phase variation due to phase-variable expression of the P120 antigen and its selective masking of P56 epitopes. Phase-variable masking may confer previously unrealized adaptive capabilities on mycoplasmas.

The cytosolic HinT protein of Mycoplasma hominis interacts with two membrane proteins

Histidine triad nucleotide-binding (HinT) proteins are dimeric proteins that bind to purines and are found in all three kingdoms: the eukarya, bacteria and archaea. In eukaryotes, HinT proteins have been detected intracellularly, but their function is unknown. Until now, knowledge about HinT proteins in prokaryotes was restricted to sequence similarities and nucleotide-binding studies. In this study, we provide evidence that, in the cell wall-less prokaryote, Mycoplasma hominis, the gene encoding the HinT protein forms an operon with two other genes. These genes encode the species-specific membrane proteins, P60 and P80, which are associated within the mycoplasma membrane. The finding that HinT interacts with this complex by binding to P80 provides novel insight into the organization of bacterial HinT proteins.

Characterization of the variability of a 75-kDa membrane protein in Mycoplasma hominis

The gene p75 encoding a 75-kDa surface-exposed membrane protein P75 was cloned and sequenced from Mycoplasma hominis type strain PG21T. To investigate the intraspecies variability, sequences were obtained from an additional two isolates 7488 and 183, and the three sequences were compared. The nucleotide and amino acid differences were not confined to specific regions of the gene/protein, but when comparing the three sequences, differences were present as single site substitutions or small insertions or deletions of nucleotides/amino acids. The intraspecies variability was further investigated by restriction enzyme analysis with two restriction enzymes (Alul and MboII) of PCR products amplified from p75 from 28 M. hominis isolates. On the basis of band patterns produced by the two restriction enzymes, the isolates could be divided into five and six groups. These groups neither matched categories of the M. hominis vaa gene nor the M. hominis p120 gene classes, indicating that the three genes vary by different mechanisms and possibly indicating horizontal gene transfer. Federation of European Microbiological Societies.

[Association of TAP1/TAP2 gene polymorphism with inflammatory urogenital diseases combined with joint diseases]

AIM

To study association of TAP1/TAP2 gene polymorphism with urogenital infections combined with joint lesions.

MATERIALS AND METHODS

Of 139 patients examined 45 ones had inflammation caused by Chlamydia trachomatis (17 had joint disease), 42 had Mycoplasma hominis infection (joint lesions in 17 cases). Method of amplification was used on the basis of specific primers (ARMS).

RESULTS

Patients infected with C. trachomatis significantly more frequently had allele TAP1-02011 and TAP2-0201 (RR = 18.5, p < 0.01 and RR = 4.61, p < 0.05, respectively). Joint lesion in patients with chlamydial infection was associated with allele TAP1-02011 (RR = 11.92, p < 0.05). In mycoplasmosis association with joint lesions there is a significant link of joint syndrome with heterogeneous combination threonine/alanine in gene TAP2 position 565 (RR = 4.22, p < 0.05).

CONCLUSION

The findings can be used for predicting the joint syndrome development in patients with urogenital infection.

The adherence-associated lipoprotein P100, encoded by an opp operon structure, functions as the oligopeptide-binding domain OppA of a putative oligopeptide transport system in Mycoplasma hominis

Mycoplasma hominis, a cell-wall-less prokaryote, was shown to be cytoadherent by the participation of a 100-kDa membrane protein (P100). To identify the gene encoding P100, peptides of P100 were partially sequenced to enable the synthesis of P100-specific oligonucleotides suitable as probes for the detection of the P100 gene. With this strategy, we identified a genomic region of about 10. 4 kb in M. hominis FBG carrying the P100 gene. Analysis of the complete deduced protein sequence suggests that P100 is expressed as a pre-lipoprotein with a structure in the N-terminal region common to peptide-binding proteins and an ATP- or GTP-binding P-loop structure in the C-terminal region. Downstream of the P100 gene, an additional four open reading frames putatively encoding the four core domains of an active transport system, OppBCDF, were localized. The organization of the P100 gene and oppBCDF in a transcriptionally active operon structure was demonstrated in Northern blot and reverse transcription-PCR analyses, as all gene-specific probes detected a common RNA of 9.5 kb. Primer extension analysis revealed that the transcriptional initiation site was localized 323 nucleotides upstream of the methionine-encoding ATG of the P100 gene. The peptide-binding character of the P100 protein was confirmed by fluorescence spectroscopy and strongly suggests that the cytoadherence-mediating lipoprotein P100 represents OppA, the substrate-binding domain of a peptide transport system in M. hominis.

A GTP-binding protein of Mycoplasma hominis: a small sized homolog to the signal recognition particle receptor FtsY

A protein homologous to the Escherichia coli FtsY which in turn has characteristics in common with the alpha-subunit of the eukaryotic signal recognition particle receptor (SRalpha) in the membrane of the endoplasmic reticulum, was identified in Mycoplasma hominis and its encoding DNA sequenced. The aa similarity to E. coli FtsY and B. subtilis FtsY was 38% and 51%, respectively. The protein was synthesized in E. coli, purified and shown to bind GTP. Subcellular localization studies revealed that M. hominis FtsY was associated with the cytoplasmic side of the plasma membrane. The molecular mass of M. hominis FtsY was 39.1, which was significantly smaller than FtsY from the gram- E. coli. Analysis of the primary structure showed that M. hominis FtsY had no counterpart to the N-terminal part in E. coli FtsY or mammalian SRalpha, which for the last-mentioned are known to comprise the membrane-anchoring fragment. Comparison of sequenced SRalpha homologue indicates that M. hominis together with Bacillus subtilis comprise a distinct cluster of similar small SRP receptors.

Evaluation of the Etest for detection of tetracycline resistance in Mycoplasma hominis

The Etest was compared with microbroth dilution for performing in vitro susceptibility tests in 38 isolates of Mycoplasma hominis chosen to represent a wide range of MIC values. MIC50s were 4 micrograms/ml for both methods; whereas, MIC90s were 64 and > 256 micrograms/ml for broth and Etest, respectively. Etest MICs determined on SP 4 agar were usually two or more dilutions greater than microbroth MICs in SP 4 broth, and values were prone to change by one to two dilutions when different inoculum densities were used. Inocula of 10(5) to 10(6) color-changing units/ml gave the most consistently readable MICs, with discrete colony formation surrounding the ellipse. Etest MICs for 5 isolates tested a second time at the same inoculum on SP 4 agar agreed with the original value within 1 dilution. For 12 isolates tested on A 8 agar simultaneously with SP 4 agar, MICs for 10/12 agreed within one dilution; whereas, in the other 2 isolates, MICs varied by two dilutions. These findings suggest that the Etest, when properly controlled, can be used to determine tetracycline MICs for M. hominis.