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PubMed2003

Bulk tank milk analysis: factors associated with appearance of Mycoplasma sp. in milk.

Factors associated with the presence of Mycoplasma sp. in bulk tank milk samples were evaluated from 664 herds during 2.25 years. Milk quality components were not strongly related to the presence of Mycoplasma sp. in bulk tank milk. The presence of other contagious mastitis pathogens, Staphylococcus aureus and Streptococcus agalactiae, was also not related to the presence of mycoplasma, suggesting that the aetiology and transmission of mycoplasma mastitis were different from transmission of other contagious mastitis pathogens. The occurrence of the first isolation of mycoplasma from a bulk tank was not correlated to season of the year. Mycoplasma in bulk tank milk samples were more likely to be found in herds shipping more milk, an indirect measure of herd size. This suggests that larger herds are more likely to have mycoplasma mastitis. However, the first appearance of mycoplasma mastitis in a bulk tank sample was followed by a sample without this pathogen in more than 60% of herds. Mycoplasma sp. was not detected in any herd a year after first isolation. These findings suggest that this pathogen could be controlled and eliminated from herds.

Animals↗

PubMed2005

Gordon Memorial Lecture. Poultry mycoplasmas: sophisticated pathogens in simple guise.

Mycoplasmas are a genus within the class Mollicutes (trivial name mollicutes), which are the smallest known prokaryotes capable of self-replication. They have a very small genome, and have evolved to this 'minimalist' status by losing non-essential genes, including those involved in cell wall synthesis. The mollicutes exploit their limited genetic material to the maximum and many are successful pathogens in man, animals, birds and plants. Most of those of veterinary importance are in the genus Mycoplasma and include 4 poultry pathogens of economic importance: Mycoplasma gallisepticum, Mycoplasma synoviae, Mycoplasma meleagridis and Mycoplasma iowae. The pathogenetic mechanisms of mycoplasmas are not fully understood, but they are successful pathogens because they can enter the host and multiply, evade the defence mechanisms, cause damage and escape to infect new hosts. M. gallisepticum is one of several motile species and possesses a terminal tip structure that mediates adherence to its target tissues. For some species, including M. gallisepticum, some of the organisms may become intracellular. Some Mycoplasma species, including the pathogenic poultry species, have a remarkable ability to vary their major surface antigens, a mechanism that is thought to help them to persist in their host by evading the immune response. The molecular and cellular events that lead to the development of lesions and clinical disease are still obscure. Some lesions appear to be the result of indirect damage from the host's inflammatory and cellular responses. Despite short survival times in the environment, mycoplasmas are able to transmit successfully to new hosts. In poultry flocks there is both horizontal and vertical transmission, the former being encouraged by intensive husbandry and stress factors. Establishing the pathways of transmission and the possible role of other birds, such as game and wild birds, as intermediate vectors between poultry flocks is now greatly aided by the availability of modern molecular methods for strain typing.

Animals↗

PubMed1997

Antibiotic susceptibilities of mycoplasmas and treatment of mycoplasmal infections.

Mycoplasmas are the smallest free-living microorganisms, being about 300 nm in diameter. They are bounded by a triple-layered membrane and, unlike conventional bacteria, do not have a rigid cell wall. Hence, they are not susceptible to penicillins and other antibiotics that act on this structure. They are, however, susceptible to a variety of other broad-spectrum antibiotics, most of which only inhibit their multiplication and do not kill them. The tetracyclines have always been in the forefront of antibiotic usage, particularly for genital tract infections, but macrolides are also widely used for respiratory tract infections. Indeed, in comparison with the tetracyclines, erythromycin, the newer macrolides, the ketolides and the newer quinolones have equal or sometimes greater activity. The two latter antibiotic groups also have some cidal activity. The antibiotic susceptibility profiles of several mycoplasmas of human origin are presented, those of Mycoplasma pneumoniae and Mycoplasma genitalium being similar. Apart from the penicillins, mycoplasmas are innately resistant to some other antibiotics, for example the rifampicins. In addition, some may develop resistance, either by gene mutation or by acquisition of a resistance gene, to antibiotics to which they are usually sensitive. Resistance of mycoplasmas to tetracyclines is common and due to acquisition of the tetM gene. The antibiotic susceptibility pattern may be influenced greatly by the source of the mycoplasma; for example, one recovered from a contaminated eukaryotic cell culture that has been subjected to extensive antibiotic treatment may have an antibiotic profile quite different from the same mycoplasmal species that has been recovered directly from a human or animal source. Mycoplasmas may be difficult to eradicate from human or animal hosts or from cell cultures by antibiotic treatment because of resistance to the antibiotic, or because it lacks cidal activity, or because there is invasion of eukaryotic cells by some mycoplasmas. Eradication may be particularly difficult in immunosuppressed or immunodeficient individuals, particularly those who are hypogammaglobulinaemic. The regimes that are most likely to be effective in the treatment of respiratory or genitourinary mycoplasmal infections are presented.

Animals↗

PubMed1998

Mycoplasmas in the etiology of multifactorial respiratory disease.

The avian mycoplasmas pathogenic for commercial poultry, Mycoplasma gallisepticum and Mycoplasma synoviae in chickens and turkeys, and Mycoplasma meleagridis and Mycoplasma iowae in turkeys are egg-transmitted infections and exhibit wide variations in clinical manifestations. Mycoplasma gallisepticum strains vary widely in virulence, tissue tropism, and antigenic makeup and have the ability to alter the expression of major surface antigenic proteins. Although less well studied, strains of M. synoviae, M. meleagridis, and M. iowae appear to exhibit similar variability. Intraspecies variability among mycoplasma strains and their ability to interact with other disease-producing factors explain the wide variability of clinical manifestations, difficulties in diagnosis, their ability to persist within the host for long periods of time, and many of the difficulties involved in control and eradication programs. Mycoplasmas are also well known for their interactions with other infectious agents and environmental factors in producing clinical disease. Control of the clinical manifestations of Mycoplasma infections is simplified when concurrent infections are minimized and optimum environmental conditions are provided.

Animals↗

PubMed2003

Characterization of a chromosomal region of Mycoplasma sp. bovine group 7 strain PG50 encoding a glycerol transport locus (gtsABC).

Mycoplasma species bovine group 7, represented by the type strain PG50, is one of six members of the Mycoplasma mycoides cluster and has been implicated in sporadic and outbreak cases of polyarthritis and mastitis in Australian dairy cattle. This study describes cloning and sequencing a 7.9 kb region of the PG50 chromosome and identification of genes involved in glycerol transport (gtsA, gtsB and gtsC) that are followed by a putative lipoprotein gene lppB and a genomic locus containing two ORFs encoding putative membrane proteins. Long range PCR using primers spanning gtsABC and downstream flanking genes, and Southern hybridization analyses using a suite of probes derived from M. mycoides subsp. mycoides small colony type (SC) strain Afadé for gtsA, gtsB and gtsC, lppB and the two downstream genes confirmed that these genes were conserved among Mycoplasma sp. bovine group 7 isolates and mycoplasmas belonging to the M. mycoides subcluster [M. mycoides subsp. mycoides SC, M. mycoides subsp. mycoides large colony type (LC) and M. mycoides subsp. capri] but were absent in mycoplasmas belonging to the Mycoplasma capricolum subcluster (M. capricolum subsp. capricolum and M. capricolum subsp. capripneumoniae). M. capricolum subsp. capricolum type strain California kid did not hybridize with the probe for gtsA and gave only weak or no hybridization signals with probes derived from the loci downstream of gtsABC, suggesting that this region has diverged in mycoplasmas belonging to subspecies of M. capricolum. It is shown that PG50, after the addition of a physiological concentration of glycerol to the growth medium, generates H(2)O(2) at levels comparable with strain Afadé, implying that the glycerol transport system is functional in Mycoplasma sp. bovine group 7. This suggests that in PG50, as in M. mycoides subsp. mycoides SC, glycerol uptake is followed by phosphorylation to glycerol 3-phosphate and then conversion to dihydroxyacetone phosphate, catalysed by L-alpha-glycerophosphate oxidase, resulting in the production of H(2)O(2). The ability of Mycoplasma sp. bovine group 7 to generate significant amounts of hydrogen peroxide may be important in pathogenesis.

Animals↗

PubMed2004

Inactivation of mycoplasma species in blood by INACTINE PEN110 process.

BACKGROUND: Mycoplasmas have been associated with multiple acute and chronic diseases. Mycoplasma genome is found in the blood of 10 to 15 percent of subjectively healthy individuals. If blood borne and viable in donated blood, mycoplasmas could potentially be transfusion transmissible. The INACTINE PEN110 technology is a pathogen reduction process that is in Phase 3 clinical studies. The present study investigated the ability of this process to eradicate mycoplasmas in human blood. STUDY DESIGN AND METHODS: Identical whole blood or RBC units inoculated with Mycoplasma arthritidis or M. pneumoniae were incubated with PEN110 (inactivating agent) for 24 hours at 23 degrees C. Sham controls were treated with buffer under the same conditions. 4 degrees C controls were put on storage immediately after the spike. RESULTS: No viable microorganisms were detected in PEN110-treated units after 24 hours of incubation. Sham controls showed no changes to mycoplasma titers during the incubation. In 4 degrees C controls, minor decrease of mycoplasma titers was observed during the storage. CONCLUSION: The INACTINE process inactivates more than 107 mycoplasma CFU per mL in whole blood and RBCs. This study is the first demonstration of susceptibility of mycoplasmas to pathogen reduction. The data provide further support for the ability of INACTINE technology to address microbial safety issues that are not well characterized.

Blood Banking↗

PubMed2005

Mast cells protect mice from Mycoplasma pneumonia.

RATIONALE: As the smallest free-living bacteria and a frequent cause of respiratory infections, mycoplasmas are unique pathogens. Mice infected with Mycoplasma pulmonis can develop localized, life-long airway infection accompanied by persistent inflammation and remodeling. OBJECTIVE: Because mast cells protect mice from acute septic peritonitis and gram-negative pneumonia, we hypothesized that they defend against mycoplasma infection. This study tests this hypothesis using mast cell-deficient mice. METHODS: Responses to airway infection with M. pulmonis were compared in wild-type and mast cell-deficient Kit(W-sh)/Kit(W-sh) mice and sham-infected control mice. MEASUREMENTS AND MAIN RESULTS: Endpoints include mortality, body and lymph node weight, mycoplasma antibody titer, and lung mycoplasma burden and histopathology at intervals after infection. The results reveal that infected Kit(W-sh)/Kit(W-sh) mice, compared with other groups, lose more weight and are more likely to die. Live mycoplasma burden is greater in Kit(W-sh)/Kit(W-sh) than in wild-type mice at early time points. Four days after infection, the difference is 162-fold. Titers of mycoplasma-specific IgM and IgA appear earlier and rise higher in Kit(W-sh)/Kit(W-sh) mice, but antibody responses to heat-killed mycoplasma are not different compared with wild-type mice. Infected Kit(W-sh)/Kit(W-sh) mice develop larger bronchial lymph nodes and progressive pneumonia and airway occlusion with neutrophil-rich exudates, accompanied by angiogenesis and lymphangiogenesis. In wild-type mice, pneumonia and exudates are less severe, quicker to resolve, and are not associated with increased angiogenesis. CONCLUSIONS: These findings suggest that mast cells are important for innate immune containment of and recovery from respiratory mycoplasma infection.

Animals↗

PubMed2003

[Prevalence and drug tolerance of mycoplasma in patients with urogenital inflammation].

OBJECTIVE: To observe the prevalence and drug tolerance of mycoplasma(Ureaplasma urealyticum and Mycoplasma hominis) in patients with urogenital inflammation. METHODS: Three thousand and fifty-five patients with urogenital inflammation such as non-gonococcal urethritis(NGU), chronic prostatitis or pelvic inflammation from 1999 to 2003 were included. The results of mycoplasma culture and drug sensitivity test were analyzed. RESULTS: A total of 992(32.5%) cases were mycoplasma positive in the 3,055 patients, and there was no significant difference in the yearly positive percentage in the 5 years (P < 0.05). Among them, 701(70.7%) were infected with Ureaplasma urealyticum, 44(4.4%) with Mycoplasma hominis, and 247(24.9%) with both Ureaplasma urealyticum and Mycoplasma hominis, the Ureaplasma urealyticum infection rate being much higher than that of Mycoplasma hominis and mixed infection (P < 0.01). The high colony counting(> or = 10(4) cfu/ml) in Ureaplasma urealyticum infection patients accounted for 76.7%, while Mycoplasma hominis infection represented only 18.2%. The results of drug tolerance test showed a higher sensitivity to doxycycline, pristinamycin, josamycin and tetracycline (94.3%, 96.6%, 86.5% and 97.4% respectively), and a lower sensitivity to erythromycin and ofloxacin (54.8% and 29.4% respectively). CONCLUSIONS: Ureaplasma urealyticum and Mycoplasma hominis should be detected simultaneously and the drug tolerance test is needed for the selection of appropriate antibiotics.

Adolescent↗

PubMed1996

Effects of Mycoplasma fermentans on the myelomonocytic lineage. Different molecular entities with cytokine-inducing and cytocidal potential.

Mycoplasma fermentans is a mycoplasma species that has been accused of serving as a cofactor of AIDS development. Here, we show that M. fermentans affects the function of human monocytes and myelomonocytic cell lines on at least two different levels. Heat-inactivated mycoplasma particles induce inflammatory cytokines such as IL-1, IL-6, and TNF in monocytes, as well as in THP-1 cells. Moreover, M. fermentans induces IL-10 (but not IL-12) in freshly isolated human monocytes. The cytokine-inducing effect is mediated by lipid-associated molecules. In addition, we have detected a novel biologic activity that resides in the nonlipid-associated protein fraction of M. fermentans (approximate molecular mass: 15 to 30 kDa) and that has a cytocidal effect on nondifferentiated myelomonocytic cell lines (U937 cells, HL-60 cells), as well as on actinomycin-D-sensitized monocytes. Death is accompanied by oligonucleosomal DNA fragmentation and loss of chromosomal DNA. U937 and HL-60 cells fail to produce cytokines and rather undergo cell death in response to heat-inactivated M. fermentans, provided that they are kept in a relatively undifferentiated stage. Whereas the cytokine-inducing activity is a general feature of many mycoplasma species, it appears that only a restricted panel of mycoplasma species exert a cell death-inducing activity. In addition to M. fermentans strains, Mycoplasma penetrans, another hypothetical cofactor of AIDS, possess a cytocidal activity. This does not apply to other mycoplasma species, including pathogenic ones such as Mycoplasma pneumoniae and Ureaplasma urealyticum. The cell death-inducing effect of M. fermentans is not mediated by cytokines and obeys different principles than TNF-alpha-mediated apoptosis. Thus, in contrast to TNF-alpha-induced death, it is not accompanied by a decrease in the mitochondrial transmembrane potential and is not inhibited by preincubation with the antioxidant drug N-acetylcysteine. In synthesis, it appears that certain AIDS-associated mycoplasma species perturb the function and/or generation of cells from the myelomonocytic lineage via several distinct pathways.

Acquired Immunodeficiency Syndrome↗

PubMed1997

Mycoplasma hominis and Ureaplasma urealyticum in patients with sexually transmitted diseases.

Mycoplasma hominis and Ureaplasma urealyticum can be isolated with considerable frequency from the human urogenital tract and are thought to cause various syndromes such as nongonococcal urethritis, pelvic inflammatory disease, pyelonephritis or infertility. The aim of this study was the evaluation of the presence of different genital pathogens in patients with sexually transmitted diseases (STD) and, in particular, the detection of mycoplasmas in individuals infected with genital microbes and an assessment of the presence of genital microorganisms in patients harbouring Mycoplasma hominis or Ureaplasma urealyticum. Furthermore, the occurrence of mycoplasmas in women with bacterial vaginosis was established. Specimens were collected from a total of 41,980 persons attending the Outpatients' Centre for Infectious Venero-Dermatological Diseases in Vienna from 1994 to 1996. Of all genital pathogens, Ureaplasma urealyticum was cultured most frequently in men and women. Mycoplasma hominis and Ureaplasma urealyticum were detected more often in the vaginal fluid than in the male urethra. By contrast, infection rates with Neisseria gonorrhoeae and Chlamydia trachomatis were higher in men than in women. In both men and women, trichomoniasis increased colonisation with Mycoplasma hominis, while mycoplasmas occurred less frequently together with genital candidiasis. Mycoplasma hominis was cultivated significantly more often in women with bacterial vaginosis than in those without. In contrast to urethral infections in men, cervical infections with Neisseria gonorrhoeae or Chlamydia trachomatis raised the incidence of Mycoplasma hominis in the vaginal fluid.

Adult↗

PubMed1998

Human pathogenic Mycoplasma species induced cytokine gene expression in Epstein-Barr virus (EBV)-positive lymphoblastoid cell lines.

We addressed the question whether the in vitro interaction of two Epstein-Barr virus (EBV)-genome-positive B cell lines (EB-3 and HilB-gamma) with either Mycoplasma pneumoniae or M. hominis, with the < > mycoplasma species (M. fermentans, M. fermentans subsp. incognitus, M. penetrans, M. genitalium) or with mycoplasma species known to be mere commensals of the respiratory tract (M. orale and M. salivarium) would result in expression of mRNAs for IL-2, IL-2R, IL-4 and IL-6 as determined by reverse transcriptase (RT)-PCR after 4 and 24 h of cocultivation. The pattern of cytokine gene expression observed depended on (i) the origin of the transformed cell line, (ii) the pathogenicity of the Mycoplasma species, and (iii) the length of cocultivation. The EBV-immortalized lymphoblastoid cell line HilB-gamma showed mRNA expression for IL-2, IL-2-receptor, IL-4 and IL-6 peaking 24 h after stimulation with M. pneumoniae and all AIDS-related mycoplasma species tested. The Burkitt lymphoma cell line EB-3 showed a distinct and isolated strong II-2/IL-2 R-mRNA expression within 4 h after contact with the pathogenic and all of the AIDS related mycoplasma species. In neither EBV-containing cell line cytokine was gene expression detectable after stimulation with the commensal mycoplasma species, M. orale and M. salivarium, indicating species differences in the ability of mycoplasmas to interact with and stimulate B-cell lines. Our data suggest that some mcyoplasma species may act as immunomodulatory cofactors by eliciting inappropriate cytokine gene expression in B cells latently infected with EBV. Therefore, this cultivation model may prove useful in evaluating the pathogenetic potential of novel isolated mycoplasma species.

B-Lymphocytes↗

PubMed1983

Induction of macrophage-mediated cytolysis of neoplastic cells by mycoplasmas.

Unexpected cytolysis was encountered when nonactivated murine peritoneal macrophages were cultured with [3H]TdR-prelabeled syngeneic or allogeneic tumor cells at a 10:1 ratio. The level of specific cytolysis reached 70% within 48 hr of cocultivation. Similar killing was observed whether the macrophages were derived from untreated, thioglycollate-treated, or germ-free mice. Cytolytic activity was also demonstrated when bone marrow-derived or peritoneal macrophages from 9- and 5-day in vitro cultures, respectively, were employed rather than freshly harvested peritoneal macrophages. Thus, the macrophage-mediated killing was neither the result of in vivo preactivation nor a consequence of the presence of lymphocytes in the assay. Moreover, macrophages derived from different strains caused similar effects. Our study revealed that the neoplastic target cell cultures susceptible to cytolysis by nonactivated macrophages were contaminated with mycoplasma. A mycoplasma was isolated from the supernatant of a culture of the A9HT fibrosarcoma line, identified as Mycoplasma orale, and cultivated. Addition of viable mycoplasma from that isolate to mixed cultures of thioglycollate-elicited macrophages and [3H]TdR-prelabeled mycoplasma-free target cells resulted in specific cytolysis of transformed A9 cells, but not of normal mouse fibroblasts. The level of macrophage-dependent cytolysis correlated with the number of viable mycoplasma cells added and was higher than that attained by activation with LPS at optimal concentration. Similar specific cytolysis was observed with heat-killed mycoplasmas. Our results demonstrate that mycoplasmas may cause selective macrophage-mediated cytolysis of neoplastic but not of normal target cells, perhaps via activation of the macrophages. It is suggested that undetected infection of experimental systems by mycoplasmas may account for some reports on lysis of neoplastic cells by nonactivated macrophages.

Animals↗

PubMed1990

Fast and simple procedure for the detection of cell culture mycoplasmas using a single monoclonal antibody.

The detection of mycoplasmas in cell cultures is still a problem, especially in those laboratories in which the detection and identification of microorganisms is not established as a routine procedure. In our laboratory, monoclonal antibodies (mAbs) have been prepared to Acholeplasma laidlawii, Mycoplasma hyorhinis, Mycoplasma orale, Mycoplasma arginini and Mycoplasma salivarium. 30 mAbs were obtained and one of these, designated CCM-2, was shown to bind to all five mycoplasma species. It also bound to Mycoplasma fermentans, Mycoplasma hominis and to all wild types (n = 54), isolated from cell cultures submitted to our laboratory. The mAb was used in a immunofluorescent assay (IF) and the method correlated with the microbiological assay. Using this mAb immunofluorescent staining of cells is a fast and simple procedure for mycoplasma detection in cell cultures.

Animals↗

PubMed1992

Detection of mycoplasma contamination through modulation (stimulation or inhibition) of thymidine incorporation by unstimulated mouse spleen cells.

In the present report we describe a rapid and sensitive assay for mycoplasma detection in cell cultures. The assay is based on the ability of contaminated culture supernatants to modulate [3H]TdR incorporation by unstimulated mouse splenocytes. Several mycoplasma species (Mycoplasma orale, culturable and non-culturable strains of Mycoplasma hyorhinis) inhibited [3H]TdR incorporation and permitted the detection of some contaminated cell cultures that would otherwise have escaped detection in assays measuring [3H]TdR incorporation by mitogen-stimulated splenocytes. On the other hand, several other mycoplasma species (Mycoplasma arginini, Mycoplasma hominis) strongly enhanced [3H]TdR incorporation by unstimulated splenocytes. This enhancement was optimally detectable on day 2 after initiation of the cultures. The sensitivity of the assay was determined for a mycoplasma species (culturable M. hyorhinis) that inhibited as well as for one (M. arginini) that enhanced [3H]TdR incorporation. In both cases, the sensitivity was such that 1-3 x 10(2) mycoplasma colony-forming units (CFU) could be detected.

Animals↗

PubMed1985

Immune responses to mycoplasma infections of the respiratory tract.

Mycoplasmas are capable of causing respiratory disease in a number of species of animals. The pathogenicity of the mycoplasma species ranges from those that cause major disease outbreaks and economic loss to what might be considered the more highly evolved and successful parasites at the other end of the spectrum that survive for long periods in the host without being recognised and evicted. This prolonged colonisation of mucous membranes which is typical of many mycoplasmas is related to certain unique features of the mycoplasma and its interaction with the hosts immune system. An initial step in infection is the attachment of the mycoplasma to the epithelial lining of the respiratory tract. Lack of cell wall confers plasticity and may engender the intimate association of mycoplasma and host cell that has been noted. This in turn may favour persistence of the extracellular parasite. Before the specific immune response is produced avoidance of the non-specific immune mechanisms would clearly aid survival. Both passive (capsules) and active (toxic effects) mechanisms of avoiding phagocytosis have been proposed. Both humoral and cell mediated responses are generated by mycoplasma infections. The serum antibody response follows the usual course IgM, G and A. The indications of cell mediated immunity that have been reported include; delayed type hypersensitivity reactions, lymphocyte transformation responses and inhibition of macrophage migration. The concept that the pathological lesions are in a large part due to host reactivity is well accepted. The lung lesions may contain infiltrating and dividing lymphocytes some of which are producing specific antibody. Evidence for the lung lesion in some animals being partly due to the hosts cell mediated response has also been produced. The local immune response appears to be of greater relevance to immunity to infection than the systemic response, in general the association between local antibody and immunity is much better than for serum antibody. Of particular note is the high contribution of local IgG production, particularly in the lower respiratory tract. Attempts are now being made to use this increased understanding to produce effective killed vaccines that produce immune responses in the lung. Such studies will hopefully lead to the development of 'killed' vaccines that are effective. It can be urged that mycoplasmas would be less pathogenic if they did not produce an inflammatory response and some species have been shown to have an immunosuppressive effect. Such a property could affect the lesion, and hence pathogenicity, and also aid mycoplasma persistence.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

PubMed1985

Medium-dependent properties of mycoplasmas.

Without a cell wall, the morphology, growth rate, and composition of mycoplasmas are culture media-dependent with variable properties best described as environmentally related. The adaptation of mycoplasmas to either a tissue cell or cell-free culture media, with dependency upon specific animal or plant products for survival, has led to investigations of their human host-related properties. The influence of culture media on the antibiotic sensitivities of mycoplasmas was measured by use of three different broths in two different assay systems. The variable results indicate that the inhibition of mycoplasma protein synthesis or growth may also be host-tissue dependent. The addition of noninhibitory penicillins to different culture media was found to affect the composition and antigenicity of some mycoplasmas. Using the complement fixation test, we found some human sera that were more reactive than rabbit antisera to mycoplasmas cultured in human synovial broth or in myelin-enriched broth. Mycoplasmas cultured in human lung broth and pig lung broth had media-dependent antigenicity. The antigenicity and the growth of mycoplasmas were found to depend on the proteolytic enzymes used to provide the essential peptides in tissue broths. The media-affected mycoplasmas indicate the presence of species-, strain-, and tissue-specific antigen sites that may determine immunopathogenicity in the genetically susceptible host.

Adaptation, Physiological↗

PubMed1975

Isolation of genital mycoplasmas from blood obtained shortly after vaginal delivery.

Blood obtained from three hundred and twenty-seven women within a few minutes of vaginal delivery was cultured for genital mycoplasmas (Mycoplasma hominis and T mycoplasmas). Twenty-six (8%) of the women had genital mycoplasmas isolated from their blood. Ten women had blood-cultures which contained M. hominis. Fifteen women had blood-cultures which contained T mycoplasmas. Both M. hominis and T mycoplasmas were isolated from the blood of one woman. Only one of two hundred and seventy-three blood-cultures obtained 1 or more days after delivery contained mycoplasmas. The isolation of M. hominis, but not of T mycoplasmas, from the blood was associated with vaginal colonisation and a serological response to the homologous isolate. Two of ten women whose blood contained M. hominis gave birth to stillborn infants. In contrast, there were only four (1.3%) stillbirths among the infants born to the three hundred and one women whose blood did not contain mycoplasmas. This difference is statistically significant.

Adolescent↗

PubMed2003

The pyruvate dehydrogenase complex of Mycoplasma hyopneumoniae contains a novel lipoyl domain arrangement.

The genes encoding the pyruvate dehydrogenase (PDH) complex (pdhA, pdhB, pdhC and pdhD) from Mycoplasma hyopneumoniae have been cloned and sequenced. The genes are arranged into two operons, designated pdhAB and pdhCD, which are not found together in the chromosome. The pdhA, pdhB, pdhC and pdhD genes encode proteins of predicted molecular masses of 44.2 kDa (pyruvate dehydrogenase major subunit; E1alpha), 36.6 kDa (pyruvate dehydrogenase minor subunit; E1beta), 33.1 kDa (dihydrolipoyl acetyltransferase; E2) and 66.3 kDa (dihydrolipoyl dehydrogenase; E3), respectively. Sequence analysis of the pdhCD operon revealed the presence of a lipoyl-binding domain in pdhD but not in pdhC. The lipoyl domain is believed to act as a "swinging arm" that spans the gaps between the catalytic domains of each of the subunits. Portions of the N-terminal regions of pdhA and pdhD were expressed as 6xHis-tag fusion proteins in Escherichia coli and purified by nickel affinity chromatography. The purified proteins were used to raise antibodies in rabbits, and Western blot analysis was performed with the polyclonal rabbit antiserum. Both the pdhA and pdhD genes were expressed among various strains of M. hyopneumoniae as well as the porcine mycoplasmas, Mycoplasma hyorhinis and Mycoplasma flocculare. Southern hybridisation analysis using probes from pdhA and pdhD detected one copy of each gene in the chromosome of M. hyopneumoniae. Since previous studies have shown pyruvate dehydrogenase activity in M. hyopneumoniae [J. Gen. Microbiol. 134 (1988) 791], it appears likely that a functional lipoyl-binding domain in the N terminus of PdhC is not an absolute prerequisite for pyruvate dehydrogenase enzyme activity. We hypothesise that the lipoyl-binding domain of PdhD is performing the enzymatic function normally attributed to the PdhC lipoyl-binding domain in other organisms. Searches of pyruvate dehydrogenase gene sequences derived from other Mycoplasma species showed that a putative lipoyl domain was absent in the pdhC gene from Mycoplasma pulmonis. However, like other bacterial species, pdhC gene sequences from Mycoplasma capricolum, Mycoplasma genitalium and Mycoplasma pneumoniae contain a putative lipoyl domain.

Amino Acid Sequence↗