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PubMed2005

Real-time polymerase chain reaction for the qualitative and quantitative detection of Mycoplasma gallisepticum.

The aim of this study was to evaluate the sensitivity and the detection limit of a real-time polymerase chain reaction (Q-PCR) developed for the qualitative and quantitative detection of Mycoplasma gallisepticum. No cross-reactivity was observed with DNA from other important avian mycoplasmas, including Mycoplasma synoviae and Mycoplasma meleagridis. However, the Q-PCR could not distinguish between M. gallisepticum and Mycoplasma imitans. The Q-PCR had detection limits 10 to 1000 times lower than a conventional commercial PCR method and than culture. The Q-PCR was used quantitatively by incorporating a set of external M. gallisepticum DNA standards, derived from a M. gallisepticum log-phase culture of a known concentration. The number of colony-forming unit equivalents per millilitre in tracheal swabs from experimentally infected birds could be determined from a single sample. The method had good reproducibility and correlated well with standard counting techniques using culture. It can be concluded that the Q-PCR described is suitable for qualitative and quantitative detection of M. gallisepticum in clinical samples.

Animals↗

PubMedDate not supplied

Attachment of mycoplasmas to host cell membranes.

Pathogenic mycoplasmas rarely invade the tissues or bloodstream. Their adherence to epithelial cell surface, the first stage in disease, involves protein binding sites on the mycoplasmal cell membrane and receptors on the host cell membrane. Strong evidence indicates that Mycoplasma gallisepticum and Mycoplasma pneumoniae adhere with the aid of sialic acid residues on host cells, but the data do not preclude participation by other host-cell membrane components. Several studies indicate that these mycoplasmas adhere by blebs or terminal structures; others suggest that binding occurs via other cell areas. Scanning electron microscopy suggests tight interaction between these mycoplasmas and red blood cell membranes, causing imprints resembling those from interaction of viruses with red blood cells. Because sialoglycoproteins are major sites for attachment of M. pneumoniae to respiratory epithelium and red blood cells, glycophorin--the major sialoglycoprotein of human red blood cells--was the ligand used in affinity chromatography for isolation of the binding sites specific for sialic acid receptors from M. pneumoniae membranes solubilized by detergents. The fraction eluted with 0.2% sodium dodecylsulfate from the glycophorin-Sepharose column, highly enriched with two proteins, exhibited high binding capacity to glycophorin-Sepharose beads and lower binding capacity to human red blood cells. The latter capacity was nearly abolished by glycophorin, but not by its hydrophobic moiety.

Adhesiveness↗

PubMedDate not supplied

Immunological interactions between host cells and mycoplasmas: an introduction.

In addition to eliciting host immune responses, many mycoplasmas interact nonspecifically with host cells. Early reports revealed peculiar inhibitory and stimulatory effects of mycoplasmas on the immune response in vivo; several investigators have now clearly defined nonspecific stimulation of B and T lymphocytes and also a nonspecific immunosuppressive effect on experimental animals and humans. These interactions relate to attachment of mycoplasmas to host cell membranes and perhaps involve sharing of membrane components. The implications of these peculiar effects of mycoplasmas on host cells suggest that much of the disease seen in the infected host is due to a nonspecific, inflammatory response to the mitogenic properties of the organism. Since the organism becomes intimately involved with the host cell membrane, this could enable the organism to evade the immunologic surveillance system and thus achieve the prolonged surface colonization characteristic of many mycoplasmas.

Animals↗

PubMed2005

Mycoplasma pneumoniae infection in children with acute respiratory infection.

A prospective study was performed on 93 children admitted to Kasturba Medical College Hospital, Manipal and TMA Pai Rotary Hospital of Udupi and Karkala. Blood samples from 93 children admitted to the ward with no respiratory illness were taken as age-matched controls for the inpatients, IgM antibody against Mycoplasma pneumoniae was detected using a commercial kit (Virion-Serion ELISA, Germany) following the manufacturer's instructions. 23.96% of the inpatients with respiratory tract symptoms had IgM antibodies against Mycoplasma pneumoniae. The highest infection rate was found to be in the 2-5 and 5-10 year age group. The most common mode of presentation was an upper respiratory focus of infection with cervical lymphadenopathy. Bronchial breathing signifying pneumonic consolidation was significantly less in the Mycoplasma positive group (p = 0.006). There was no statistically significant difference in the radiological findings in the Mycoplasma positive and Mycoplasma negative groups.

Age Distribution↗

PubMed1993

Mycoplasma corogypsi sp. nov., a new species from the footpad abscess of a black vulture, Coragyps atratus.

Strain BV1 was isolated from the exudate of the footpad abscess of a black vulture (Coragyps atratus). The colonies had a "fried-egg" appearance consistent with that of mycoplasmal species. Electron microscopic examination of the cells revealed irregular elongated or elliptical forms and smaller circular budding processes. Profuse growth was observed in Frey medium supplemented with 20% swine serum at 37 degrees C in a humidified atmosphere of 10% CO2 and air. Typical of mycoplasma, strain BV1 required sterol for growth and catabolized glucose but did not hydrolyze arginine or urea. The guanine-plus-cytosine content of the DNA was 28 mol%. The organism demonstrated the ability to hemolyze, absorb onto, and agglutinate the erythrocytes from several animal species. Strain BV1 was serologically unrelated by the growth inhibition test to previously established Mycoplasma, Acholeplasma, Entomoplasma, and Mesoplasma species, as well as to strains belonging to these genera but not identified to species level. Moreover, BV1 had a 16S rRNA gene with a nucleotide sequence distinct from reported sequences of other mycoplasmas. This organism represents a new species for which the name Mycoplasma corogypsi is proposed. Strain BV1 (ATCC 51148T) is the type strain of Mycoplasma corogypsi sp. nov.

Abscess↗

PubMed2000

Updated phylogenetic description of the Mycoplasma hominis cluster (Weisburg et al. 1989) based on 16S rDNA sequences.

The fastidious nature of the mollicutes (mycoplasmas), their lack of a classic bacterial cell wall, and their very small genome, make phylogenetic placements of new species in this enlarging group of prokaryotes an important and valuable aid in their classification. In this report we have determined the phylogeny of the Mycoplasma hominis cluster of the hominis group. The 16S rDNA sequences from several previously described Mycoplasma species were determined and ten species were found to belong to the M. hominis cluster. With almost complete sequences available, the phylogenetic analysis revealed that the M. hominis cluster currently comprises 19 species, forming a distinct clade as judged from branch lengths, bootstrap percentage values, nucleotide signature analysis, and structural elements in the 16S rRNA molecule. The 16S rRNA gene sequences of species in the M. hominis cluster were found to be > or = 94% similar and the range within which similarities can be used in the classification of new species is discussed. Members of the M. hominis cluster all share a major biochemical property of M. hominis, in that they hydrolyse arginine and are incapable of fermenting glucose. This consistency in phenotypic pattern has not been found in any of the other phylogenetic clusters of the hominis group. Two species, the non-cultivable agent of Grey Lung disease in rodents (tentatively named 'Candidatus Mycoplasma ravipulmonis') and the avian species Mycoplasma gypis strain B1/T1T, were regarded as close relatives to the M. hominis cluster, but are clearly separated from the species of this cluster. Both species formed early branches of the M. hominis cluster and should be regarded as individual lines containing one species.

DNA, Bacterial↗

PubMed2000

Lymphocytic infiltration in the chicken trachea in response to Mycoplasma gallisepticum infection.

A prominent feature of disease induced by Mycoplasma gallisepticum is a lymphoproliferative response in the respiratory tract. Although this is also seen in other mycoplasma infections, including Mycoplasma pneumoniae, the phenotype of the lymphocytes infiltrating the respiratory tract has not been determined. In this study, the numbers and distribution of lymphocytes in the tracheas of chickens infected with a virulent strain of M. gallisepticum were examined. Three groups of chickens were experimentally infected with M. gallisepticum and three unchallenged groups were used as controls. One infected and one control group were culled at 1, 2 and 3 weeks post infection. Tracheas were removed and examined for the presence and number of T cells carrying CD4, CD8, TCRgamma7, TCRalphabeta1 or TCRalphabeta2 markers. There was no significant difference in the number of CD8+ cells in the upper, middle and lower trachea. High numbers of both CD4+ and CD8+ cells were found with variable numbers of TCRalphabeta1+ and TCRalphabeta2+, but no TCRgammadelta+, cells throughout the time course. The distribution of CD4 cells was dispersed, while the CD8+ cells were clustered in follicular-like arrangements. No difference was detected in the distribution of TCRalphabeta1+ and TCRalphabeta2+ cells. The titre of mycoplasma genomes in the trachea decreased significantly from 1 to 2 weeks, while the mucosal thickness of the trachea increased significantly from 1 to 2 weeks then decreased from 2 to 3 weeks, indicating resolution of the lesions following control of infection. This study is the first to examine the phenotypes of T lymphocytes infiltrating the respiratory tract during mycoplasma infections. The findings suggest involvement of specific stimulation of CD8+ cells, particularly in the acute phase of disease.

Animals↗

PubMed1999

Antigenic characterization and cytolocalization of P35, the major Mycoplasma penetrans antigen.

Mycoplasma penetrans is a mycoplasma with unique morphology, recently identified in urine samples collected from HIV-infected patients. This mycoplasma has been found to be statistically associated with HIV infection, and to be cytopathic in vitro. The dominant antigen recognized during natural and experimental infections is an abundant lipoprotein, P35, which, upon extraction, segregates in the Triton X-114 detergent phase. It is used as the basis of M. penetrans-specific serological assays. Although mycoplasma lipoproteins, including M. penetrans P35, are the main antigens recognized by the host humoral immune response, very little is known about the nature of the epitopes involved. Immunoelectron microscopy revealed that all P35 is exposed at the cell surface and is distributed all over the membrane. P35 linear B-epitopes were mapped by an ELISA approach based on a set of overlapping peptides covering the entire mature polypeptide. The immunoreactivity of the peptides was first tested with sera from immunized animals. The dominant B-epitopes were found at the C- and N-terminal regions, in partial agreement with algorithmic predictions. Patient sera were evaluated with the same assay. Only some reacted with linear epitopes whereas others did not, indicating the importance of P35 nonsequential epitopes. Statistical analysis of the results allowed the definition of a set of peptides which were clearly immunodominant. Finally, the P35-encoding gene was modified by in vitro mutagenesis to allow the production and purification of a recombinant protein (rP35delta0) in Escherichia coil. The antigenicity of rP35delta0 was tested by Western blotting and compared to that of another recombinant product, rP35delta3, a truncated P35 polypeptide. Although rP35delta0 reacted with the M. penetrans-seropositive patient sera tested, rP35delta3 was only immunoreactive with one of six sera. This result confirmed that P35-nonsequential epitopes dominate during M. penetrans infection. Our results have important implications for the understanding of lipoprotein antigenicity during mycoplasma infections. In addition, the P35-derived immunodominant synthetic peptides defined in this study, as well as the purified rP35delta0, provide the antigenic material for the necessary improvement of M. penetrans serological assays.

Amino Acid Sequence↗

PubMed2005

16S rDNA PCR and denaturing gradient gel electrophoresis; a single generic test for detecting and differentiating Mycoplasma species.

Diagnosis of Mycoplasma infection is normally based on culture and serological tests, which can be time-consuming and laborious. A number of specific PCRs have been developed but to date there has not been a single generic test capable of detecting and differentiating mycoplasmas to a species level. This report describes the development of a new diagnostic test based on PCR of the 16S rRNA gene with Mycoplasma-specific primers and separation of the PCR product according to primary sequence using denaturing gradient gel electrophoresis (DGGE). DGGE enabled the differentiation of 67 Mycoplasma species of human and veterinary origin and represents a significant improvement on current tests as diagnosis of Mycoplasma infection can be made directly from clinical samples in less than 24 h.

Animals↗

PubMed1987

Demonstration of cross-reactive antibodies to mycoplasmas in human sera by ELISA and immunoblotting.

Varying levels of cross-reactivity to some mycoplasma species were observed in the sera of patients infected with Mycoplasma pneumoniae and even in normal human sera by enzyme-linked immunosorbent assay (ELISA). The absorption of the patients' sera with M. pneumoniae lysate showed the decrease in ELISA titers not only to M. pneumoniae, but also to other mycoplasma species. These results suggested the existence of cross-reactive antibodies to mycoplasmas in human sera. Cross-reactive antibodies to M. pneumoniae and other mycoplasmas in the patients' sera were also demonstrated by Western blotting technique.

Antibodies, Bacterial↗

PubMed2004

Lipid-associated membrane proteins of Mycoplasma fermentans and M. penetrans activate human immunodeficiency virus long-terminal repeats through Toll-like receptors.

Mycoplasmas are known to enhance human immunodeficiency virus (HIV) replication, and mycoplasma-derived lipid extracts have been reported to activate nuclear factor-kappaB (NF-kappaB) through Toll-like receptors (TLRs). In this study, we examined the involvement of TLRs in the activation of HIV long-terminal repeats (LTR) by mycoplasma and their active components responsible for the TLR activation. Lipid-associated membrane proteins (LAMPs) from two species of mycoplasma (Mycoplasma fermentans and M. penetrans) that are associated with acquired immune-deficiency syndrome (AIDS), were found to activate HIV LTRs in a human monocytic cell line, THP-1. NF-kappaB deletion from the LTR resulted in inhibition of the activation. The LTR activation by M. fermentans LAMPs was inhibited by a dominant negative (DN) construct of TLR1 and TLR6, whereas HIV LTR activation by M. penetrans LAMPs was inhibited by DN TLR1, but not by DN TLR6. These results indicate that the activation of HIV LTRs by M. fermentans and M. penetrans LAMPs is dependent on NF-kappaB, and that the activation of HIV LTR by M. fermentans LAMPs is mediated through TLR1, TLR2 and TLR6. In contrast, the LTR activation by M. penetrans LAMPs is carried out through TLR1 and TLR2, but not TLR6. Subsequently, the active component of M. penetrans and M. fermentans LAMPs was purified by reverse-phase high-performance liquid chromatography (HPLC). Interestingly, the purified lipoprotein of M. penetrans LAMPs (LPMp) was able to activate NF-kappaB through TLR1 and TLR2. On the other hand, the activation of NF-kappaB by purified lipoprotein of M. fermentans LAMPs (LPMf) was mediated through TLR2 and TLR6, but not TLR1.

Cell Line↗

PubMed1982

Mycoplasmas and mites in the ears of clinically normal goats.

Mycoplasmas were detected in the external ear canal of goats by swabbing and culture. Up to 10(8) colony forming units were recovered from single swabs. The resulting cultures were usually mixtures of mycoplasmas containing up to 5 species. The species present in sequential swabs varied. Pathogenic species (M.agalactiae, M.capricolum, M.mycoides subsp. capri, M.mycoides subsp. mycoides of the large colony (LC) type, M.putrefaciens) were isolated from the ears and in addition 3 untyped mycoplasmas G, U and V were often present. The same mycoplasmas were found in large numbers in the mites Psoroptes cuniculi and Raillietia caprae which were sometimes present in the external ear canal. The role of the mycoplasmas in the external ear canal as a source of infection and disease and of the mites in the spread of infection requires further elucidation.

Animals↗

PubMed2006

Activities of antimicrobial peptides and synergy with enrofloxacin against Mycoplasma pulmonis.

We showed in a previous study that associations of antimicrobial peptides (AMPs), which are key components of the innate immune systems of all living species, with the fluoroquinolone enrofloxacin can successfully cure HeLa cell cultures of Mycoplasma fermentans and M. hyorhinis contamination. In the present work, the in vitro susceptibility of M. pulmonis, a murine pathogen, to enrofloxacin and four AMPs (alamethicin, globomycin, gramicidin S, and surfactin) was investigated, with special reference to synergistic associations and the effect of the mycoplasma cell concentration. Enrofloxacin and globomycin displayed the lowest MICs (0.4 microM), followed by gramicidin S (3.12 microM), alamethicin (6.25 microM), and surfactin (25 microM). When the mycoplasma cell concentration was varied from 10(4) to 10(8) CFU/ml, the MICs of enrofloxacin and globomycin increased while those of the three other molecules remained essentially constant. The minimal bactericidal concentration of enrofloxacin (0.8 microM) was also lower than those of the peptides (6.25 to 100 microM), but the latter killed the mycoplasma cells much faster than enrofloxacin (2 h versus 1 day). The use of the AMPs in association with enrofloxacin revealed synergistic effects with alamethicin and surfactin. Interestingly, the mycoplasma-killing activities of the two combinations enrofloxacin (MIC/2) plus alamethicin (MIC/4) and enrofloxacin (MIC/2) plus surfactin (MIC/16) were about 2 orders of magnitude higher than those of the three molecules used separately. These results support the interest devoted to AMPs as a novel class of antimicrobial agents and pinpoint their ability to potentiate the activities of conventional antibiotics, such as fluoroquinolones.

Alamethicin↗

PubMed2006

Persistence of Mycoplasma hyopneumoniae in experimentally infected pigs after marbofloxacin treatment and detection of mutations in the parC gene.

The ability of Mycoplasma hyopneumoniae to persist despite fluoroquinolone treatments was investigated with pigs. Groups of specific-pathogen-free pigs were experimentally infected with M. hyopneumoniae strain 116 and treated with marbofloxacin at the therapeutic dose (TD) or half of the therapeutic dose (TD/2) for 3 days. Results showed that, despite tissue penetration of marbofloxacin, particularly in the trachea and the tracheal secretions, the treatments did not have any influence on M. hyopneumoniae recovery from tracheal swabs. Mycoplasmas were also isolated from inner organs and tissues such as liver, spleen, kidneys, and bronchial lymph nodes. Recontamination of pigs via environment could not explain mycoplasma persistence after medication, as decontamination of pigs and allocation to a new disinfected environment did not have any significant effect on the phenomenon. A significant decrease in the susceptibility level to marbofloxacin of 12 mycoplasma clones reisolated after the treatments (TD/2 and TD) was observed. Two point mutations were found in the ParC quinolone resistance-determining region (QRDR) of DNA topoisomerase IV (Ser80-->Phe and Asp84-->Asn), and one point mutation was observed just behind the QRDR of ParC (Ala116-->Glu). This is the first time that mutations in a gene coding for topoisomerase IV have been described for M. hyopneumoniae after in vivo marbofloxacin treatments in experimentally infected pigs. However, development of resistance is not sufficient to explain M. hyopneumoniae persistence in vivo since (i) marbofloxacin concentrations were above the marbofloxacin MIC of the wild-type strain and (ii) mycoplasmas reisolated after a single injection of marbofloxacin did not display an increased marbofloxacin MIC.

Animals↗

PubMed1981

Inactivation of mycoplasmas by long-chain alcohols.

In this report, we describe the inhibitory activity of long-chain alcohols on the growth of Mycoplasma gallisepticum and Mycoplasma pneumoniae. Peak inhibition was recorded with saturated primary alcohols (64 microM) varying in chain length from 16 to 19 carbon atoms. The unsaturated alcohols (oleyl, linoleyl, and linolenyl) and the secondary alcohol (pentadecan-2-ol), when employed in the same test conditions, were considerably less effective growth inhibitors than the primary saturated alcohols. Stearic and palmitic acids were also ineffective as growth inhibitors of M. pneumoniae and M. gallisepticum at a 128 microM concentration. Because these antimycoplasma agents are fatty alcohols and cholesterol is known to be required for the growth of some mycoplasmas, additional cholesterol was added in an attempt to reverse the inhibition observed with these agents. Cholesterol at a 128 microM concentration did not significantly relieve the growth inhibition observed with stearyl alcohol at a 48 microM concentration. Mammalian cell cultures were found to be significantly more resistant to the effects of these inhibitory alcohols than were the mycoplasmas. Electron micrographs showed that inclusion of stearyl alcohol in the culture medium produced changes in the cellular morphology of the treated mycoplasmas.

Alcohols↗

PubMed1972

Mycoplasma-virus interrelationships in mouse tracheal organ cultures.

The effects produced by single and mixed infections with Mycoplasma pulmonis and influenza A/PR-8 virus were studied in mouse tracheal organ cultures. M. pulmonis multiplied in the tracheal organ cultures, producing inhibition of ciliary activity and histologic tissue damage. The organism grew in close association with the cell membranes but did not appear to attach directly to the membranes or the cilia. Influenza A virus also replicated in tracheal organ cultures, producing ciliary inhibition and more extensive cytopathologic changes. Virus particles were seen by electron microscopy to attach to and cause clumping of the cilia. Simultaneous infection of the organ cultures with mycoplasma and virus resulted in more rapid inactivation of ciliary activity and greater tissue damage than occurred when the cultures were infected with only mycoplasma or virus. Presence of the virus appeared to have no effect on the growth of the mycoplasma; however, the mycoplasma partially interfered with virus replication.

Animals↗

PubMed1988

Clearance of different strains of Mycoplasma pulmonis from the respiratory tract of C3H/HeN mice.

Pathogen-free C3H/HeN mice were exposed by aerosol to Mycoplasma pulmonis PG34(ASH), UAB 5782C, M1, UAB T, or UAB CT, and clearance of mycoplasmas from the nasal passages, trachea, and lungs was determined during the first 72 h postinoculation (PI). There were differences among strains of mycoplasmas in physical removal of organisms and in killing by nonspecific factors in the nasal passages and trachea. The avirulent strain, PG34(ASH), was quickly removed from the nasal passages and trachea. Physical removal of the other mycoplasmal strains occurred slowly, with 60 to 89% of the radioactive label remaining in the nasal passages and trachea even after 72 h. There were significant differences in killing among mycoplasmal strains by nonspecific host mechanisms in the nasal passages, trachea, and lungs. Strain UAB T was quickly killed at all levels of the respiratory tract. Strains UAB 5782C and M1 were killed at all three sites by 2 to 4 h PI. The most virulent strain, UAB CT, was killed much more slowly than the other strains. However, there was no statistical difference in the relative numbers of mycoplasmas present in the lungs at 72 h PI among strains UAB CT, UAB 5782C, and M1. These studies showed that the different mycoplasmal strains were cleared from the respiratory tract by different mechanisms and suggest that the differences in virulence among the mycoplasma strains can be explained, in part, by the differences in elimination of the organisms from the respiratory tract by nonspecific host defense mechanisms.

Aerosols↗

PubMed1995

A Mycoplasma strain F38 growth-inhibiting monoclonal antibody (WM-25) identifies an epitope on a surface-exposed polysaccharide antigen.

Monoclonal antibody (MAb) WM-25 differentiates by in vitro growth inhibition Mycoplasma capricolum subsp. capripneumoniae (Mycoplasma strain F38), which causes contagious carpine pleuropneumonia, from other Mycoplasma spp. (F. R. Rurangirwa, T. C. McGuire, A. J. Musoke, and A. Kibor, Infect. Immun. 55:3219-3220, 1987). The antigen identified by MAb WM-25 was isolated from solubilized Mycoplasma strain F38 organisms by MAb WM-25 affinity chromatography and was stained with Schiff's reagent, but not with Coomassie blue, after separation by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Treatment of purified F38 polysaccharide with periodate abolished binding with MAb WM-25, and MAb WM-25 binding was blocked with laminarin, a complex oligosaccharide with beta(1-->3) sugar linkages. Purified F38 polysaccharide blocked both growth inhibition and agglutination of live F38 organisms caused by MAb WM-25 and rabbit antiserum to F38 organisms. The results in this paper demonstrate that MAb WM-25 binds a periodate-sensitive epitope on the F38 polysaccharide which is also exposed on the surface of Mycoplasma strain F38. Because MAb WM-25 also causes in vitro growth inhibition of F38, the reactive polysaccharide epitope may induce protective immune responses.

Animals↗