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[Methods of studying mycoplasma infections].

Mycoplasmas are most often responsible for respiratory and genital infections. At present, diagnosis is carried out by serology for infections caused by M. pneumoniae and by culture for infections due to genital mycoplasmas. For M. pneumoniae, new prospects may lead to a rapid diagnosis, detection by molecular hybridization and immunological detection. Also, the research of specific antibodies should benefit from a better knowledge of the major antigens. Culture of the genital mycoplasmas, U. urealyticum and M. hominis is simple, but the interpretation of their presence is difficult because they may be recovered in a commensal condition. The envisaged advances should lead to a better assessment of their pathogenicity. The role of M. genitalium, a species related to M. pneumoniae recently discovered in respiratory specimens, should be better determined by sensitive techniques developed to distinguish it from M. pneumoniae.

Anti-Bacterial Agents↗

A comparison of flow cytometry and other techniques used for diagnosing Mycoplasma infections.

Mycoplasma isolates from chickens are usually identified by a fluorescent antibody (FA) technique that requires 7 to 10 days from sampling to the completion of identification. The FA procedure uses Mycoplasma-positive antibodies conjugated with fluoroisothiocyanate (FITC) to identify the colonies of the organism on agar. This paper describes a flow cytometric procedure that uses the same antibody-FITC conjugate and can be completed in 3 or 4 days. Broilers and egg-type hens inoculated with Mycoplasma gallisepticum and M. synoviae were swabbed from the choanal cleft and cultures were grown in broth. Broth aliquots were briefly incubated with polyclonal antisera to M. gallisepticum and M. synoviae conjugated with FITC, the same reagents routinely used in the FA technique. The sample was then analyzed by flow cytometry for the association of the fluorescent label and the organism. Samples from inoculated chickens incubated with the homologous antibody-FITC had greater fluorescent intensity than did those incubated with the heterologous antibody-FITC. Diagnosis by flow cytometry was consistent with that by the FA technique except that in one trial one sample was incorrectly identified by flow cytometry as positive for M. gallisepticum, although it was not inoculated with M. gallisepticum. Also, flow cytometry did not correctly identify M. synoviae organisms as readily when broilers were inoculated with both M. gallisepticum and M. synoviae.

Agglutination Tests↗

[Mycoplasma infections].

Mycoplasmas are prokaryote microorganisms without cellular wall, that usually colonize the respiratory and urogenital mucosae. The pathogenic species for mankind are Mycoplasma pneumoniae, that produce respiratory infections, among them pneumonia, and M. genitalium, M. hominis and Ureaplasma urealyticum, that produce urinary and genital infections. The diagnosis of these infections is fundamentally based on serology, since the culture of these germs is very laborious. In a near future, the antigen or DNA detection molecular techniques will probably permit a much faster and reliable diagnosis. The tetracyclines and fluorquinolones have excellent activity against these microorganisms.

Fluoroquinolones↗

Role of innate immunity in respiratory mycoplasma infection.

Mycoplasmas are unique among respiratory pathogens. They possess very small genomes, lack cell walls and are strictly dependent on the host for survival. These pathogens have developed the ability to quickly adapt to the host environment through attachment to target cells within the host. Mycoplasmas have been identified as commensal microbial flora of healthy persons yet, infection of the upper and lower respiratory tracts can result in acute cough, fever and headache, and even chronic disease involving multiple organs. The lung contains a complex system of defense mechanisms with which to combat these pathogens, including innate (nonspecific) and acquired (specific) immune responses. Innate defenses include mechanical clearance, cellular responses provided by host phagocytes and molecular protection in the form of antimicrobial peptides. The interaction of mycoplasmas with different components of the innate immune system and mechanisms by which they incite pathology has proved elusive. The mechanisms by which pathogenic mycoplasmas evade the innate immune system are unknown. The purpose of this review is to summarize current knowledge of these interactions in the hope of identifying new avenues for research and therapy.

Animals↗

[Stimulation of erythropoiesis in mice with mycoplasma infections].

Mycoplasma arthritidis was shown earlier to induce erythropoietin-independent erythropoiesis in infected mice. This study demonstrated the increased 59Fe incorporation in the mouse spleen as early as day 4 after infection with M. arthritidis. It is known that inoculation of mice with low doses of actinomycin D (Act D) results in a specific suppression of erythropoiesis without impairing the endogenous erythropoietin production. In this study the mice were injected with Act D (80 microgram/kg body weight) daily for 5 days. One hour after the last injection the mice were sublethally irradiated and then infected with either M. arthritidis or A. laidlawii. The effect of Act D was completely reversed by both mycoplasmas which was shown by means of endogenous colony formation (there was almost no endogenous colony formation in the spleen of non-infected mice that were given Act D). The data indicate that the target cells for the mycoplasmas probably reside within the population of primitive erythropoietin-independent precursors.

Acholeplasma laidlawii↗

Avian mycoplasma infections: prototype of mixed infections with mycoplasmas, bacteria and viruses.

Mixed infections involving mycoplasmas, viruses and bacteria are well recognized in chickens. Synergism has been demonstrated between Mycoplasma gallisepticum and the viruses of Newcastle disease and infectious bronchitis and Escherichia coli, although the outcome of infection is influenced by many factors associated with the host and the organisms. Airsacculitis in broilers due to M. synoviae or M. gallinarum may be precipitated by concurrent respiratory virus infections including vaccine strains. Turkeys, geese and ducks have been less well studied, but similar interactions seem to occur. Such observations may give an indication as to the likely interactions between mycoplasmas, viruses and bacteria in other host species.

Air Sacs↗

Reactive species mediate inhibition of alveolar type II sodium transport during mycoplasma infection.

RATIONALE: Mycoplasma pneumoniae is a significant cause of pneumonia in humans. OBJECTIVES: To determine the impact of mycoplasma infection and the host inflammatory response on alveolar type II (ATII) cell ion transport in vivo and in vitro. METHODS: Mice were infected with M. pulmonis for measurements of alveolar fluid clearance (AFC) in vivo and isolation of ATII cells. ATII cells were infected in vivo for determination of epithelial Na+ channel (ENaC) total and cell surface protein levels by biotinylation and Western blot and in vitro for whole cell patch clamp recording and measurement of nitric oxide (NO) production by chemiluminescence. RESULTS: Mycoplasma infection significantly inhibited AFC at 24 h and total and amiloride-sensitive AFC by 48 h postinfection (pi). In contrast, infected myeloperoxidase-deficient mice had similar basal and amiloride-sensitive AFC values to uninfected control mice at 48 h pi. Addition of forskolin restored total and amiloride-sensitive AFC to control values at 48 h pi. ATII cells isolated from infected mice demonstrated normal alpha, beta, and gamma ENaC total protein levels; however, infected whole-lung cell-surface levels of gamma ENaC were significantly decreased. Patch-clamp recordings demonstrated a significant decrease in total and amiloride-sensitive Na+ currents at 24 h pi. ATII cells demonstrated a significant increase in the production of NO at 24 h pi and inhibition of NO by ATII cells before infection reversed the decrease in total Na+ currents. CONCLUSIONS: These data indicate that mycoplasma infection results in decreased AFC and functional ENaC via the production of reactive oxygen nitrogen intermediates.

Animals↗

Interaction between cigarette smoke and mycoplasma infection: a murine model.

Cigarette smoke has a major impact on health issues worldwide. Although genetics certainly is a factor in the sensitivity to cigarette smoke, other lung environmental factors, such as infection, potentially could interact with cigarette smoke to induce inflammatory changes associated with various diseases. Four groups of BALB/c mice (smoking only; smoking + M. pneumoniae infection; mycoplasma only; saline control) were studied for eight weeks to determine the interactive outcomes of inflammation and structural changes in the smoking plus mycoplasma group. This group did have significantly higher amounts of neutrophil degranulation in the outer airway wall area (smooth muscle to alveolar attachments) (p = 0.03) and mRNA expression of matrix metalloproteinase-9 (p= 0.045). Although there was not a significant difference in alveolar tissue elastin between the groups, the smoking plus mycoplasma group had a level approximately 20% below the other groups. Even in this relatively short duration study, it appears that an infectious process can interact with cigarette smoke to produce a destructive type of inflammatory response (activated neutrophils and metalloproteinase-9) seen in the outer airway wall area.

Animals↗

[Mycoplasma infection and cancer].

Mycoplasmas are widespread in nature as conditional pathogen, which may be the unique prokaryote that can cohabit with eukaryote and interact permanently with mammalian cells. Mycoplasma infection can be detected in many tumor tissues, continuous infection of mycoplasma can lead to transformation of mammalian cells, up-regulating expression of oncogenes, and some biologic changes of tumor cells, suggesting association of mycoplasma infection with tumorigenesis.

Animals↗

[Myositis caused by a mycoplasma infection].

UNLABELLED: Mycoplasma pneumonia infection can be associated with neurological manifestations such as meningoencephalitis, cerebellitis, aseptic meningoitis, polyradiculopathy, transverse myelitis, cranial nerve palsies and myositis [4, 5]. We report a case of a white female 11 years, 2 months old child, who presented with a 3 day history of pain in the left leg. The electromyograpy showed pathological signs. We found a serological titer of IgM antibodies for Mycoplasma pneumoniae. By treatment with erythromycin the complaints improved quickly. CONCLUSION: A myositis can be caused with an infection with Mycoplasma pneumoniae. The differential diagnosis is essential.

Antibodies, Bacterial↗

Elevation of endothelin biosynthesis in human endothelial cells with mycoplasma infection.

The effects of mycoplasma infection on the biosynthesis of endothelin-1 (ET-1) in cultured human vascular endothelial cell lines were examined to understand regulatory mechanisms of ET-1 biosynthesis and causes of angiopathy due to mycoplasma infection. The growth of normal endothelial cells from the umbilical cord vein and of an immortal endothelial cell line transfected with prepro ET-1 cDNA was decreased, while the secretion of ET-1 into the culture medium was enhanced by mycoplasma infection. However, the rate of ET-1 production in these cell cultures was much higher at the growing phase than at the stationary phase. Immunocytochemical studies with anti-ET-1 antibody and an autoradiographic examination of the labeled nuclei with 3H-TdR revealed that mycoplasma infection induced an elevation of ET-1 production in both S and non-S phase cells. The expression of prepro ET-1 mRNA as examined by in situ hybridization and by RNase protection assay was not altered by mycoplasma infection. Thus, the biosynthesis of ET-1 in vascular endothelial cells may be regulated at the posttranscriptional level.

Cell Division↗

DNA probes and PCR in diagnosis of mycoplasma infections.

Laboratory diagnosis of mycoplasma infections is hampered by the difficulty or total failure to cultivate the organisms in vitro, and by the frequently weak and poorly specific serological response of the host. DNA probes consisting of cloned ribosomal RNA genes, cDNA to mycoplasmal rRNA, synthetic 16S rRNA oligonucleotide sequences, or cloned mycoplasmal protein genes, have been developed and applied as diagnostic tools in a variety of human and animal mycoplasma infections. These included primary atypical pneumonia caused by Mycoplasma pneumoniae, urogenital infections associated with M. genitalium and Ureaplasma urealyticum, and infections with M. fermentans, M. penetrans or M. pirum--mycoplasmas recently incriminated as cofactors in AIDS. DNA probes were also designed to aid in diagnosis of mycoplasma diseases of farm and laboratory animals, and the hard-to-diagnose mycoplasma infections of cell cultures. Sensitivity of mycoplasma detection by the different probes ranged between 10(3) and 10(6) colony-forming units, a level which may not be sufficiently high for use in a clinical laboratory. The introduction of PCR has pushed aside the previously developed DNA probes, by providing faster and much more sensitive tests. The sensitive level of a PCR test can be as low as a single organism, enabling detection of mycoplasmas in patients treated with antibiotics and in asymptomatic patients. PCR becomes positive prior to serological response and is also effective in immunocompromised hosts. PCR was shown to be most valuable in detection and identification of the non-culturable plant and insect mycoplasma-like organisms (MLOs). Nevertheless, false-negative PCR results are rather common due to inhibitors of the PCR reaction in the clinical specimen, while false-positive results may occur due to contamination of the reagents with target DNA. In conclusion, the PCR procedure is still too complex to be carried out in a routine diagnostic laboratory. PCR prepackaged quality-controlled diagnostic kits are now in the process of rapid development. Once these kits become available, and at a reasonable cost, PCR will certainly take its place as a major diagnostic tool in the routine diagnosis of mycoplasma infections.

Animals↗