Mycoplasmas as agents of human disease

Protective effects of the glutathione redox cycle and vitamin E on cultured fibroblasts infected by Mycoplasma pneumoniae

The role of the glutathione (GSH) redox cycle and vitamin E as antioxidant defense systems was studied in normal human cultured skin fibroblasts infected by virulent Mycoplasma pneumoniae. In cells infected for 20 h, catalase activity was inhibited by 75% and the intracellular GSH decreased to 32% of its normal values. GSH peroxidase and oxidized glutathione (reductase activities in the infected cells were unaffected.) GSSG glutathione in the medium of the infected cells rose in accordance with the intracellular GSH decrease. The observed elevation in GSSG/GSH ratio was attributed to the increase in intracellular H2O2 content in M. pneumoniae-infected cells due to the marked inhibition in their catalase activity. The protective effect of the GSH redox cycle in infected cells was studied by depletion of cellular GSH, prior to their infection with M. pneumoniae, using buthionine sulfoximine (BSO), a selective inhibitor of gamma-glutamyl cysteine synthetase. After 16 h of incubation with BSO, the GSH levels were reduced to 38% of their normal value and recovered to 55% during 24 h after removal of the inhibitor. BSO had no effect on GSH peroxidase and catalase activities in either infected or noninfected cells. The level of malonyldialdehyde (an indicator of membrane lipid peroxidation) in BSO-treated cells infected by M. pneumoniae was 1.8 times higher than in infected controls. Cells enriched with 0.25 and 2.25 micrograms of vitamin E per mg of protein prior to their infection by M. pneumoniae revealed the following: a lesser degree of catalase inhibition, 46 and 30%, respectively, versus 64% in infected control cells that were not supplemented with vitamin E; lower levels of malonyldialdehyde, 55 and 20% increments, respectively, versus a 140% increment in infected controls; higher residual activity of lactate dehydrogenase, 76 and 96%, respectively, versus 58% in infected controls. Our data indicate that the oxidative damage induced in M. pneumoniae-infected cells due to the increase in intracellular levels of H2O2 and O2- is limited by the host cell GSH redox cycle and by supplementation with vitamin E.

Increased susceptibility to Mycoplasma infection in patients with hypogammaglobulinemia

The incidence and morbidity of Mycoplasma infections were examined in a group of 23 patients with hypogammaglobulinemia. Among this group of patients, 18 had one or more episodes of acute respiratory illness during which Ureaplasma urealyticum, Mycoplasma orale, or Mycoplasma pneumoniae were isolated from sputum. Resolution only followed institution of specific antibiotic therapy and elimination of the Mycoplasma. In addition to respiratory illness, U. urealyticum was isolated from the urine of two patients with urinary tract infection and from an area of cellulitis in another patient. M. pneumoniae was isolated from the joint of a patient with arthritis. In six patients with chronic lung disease, Mycoplasma was frequently isolated and clinical improvement, albeit transient, coincided with negative Mycoplasma culture results. These findings emphasize the unique susceptibility to Mycoplasma infection in patients with hypogammaglobulinemia.

Pulmonary involvement in Mycoplasma pneumoniae infection in families

The transmission rate and the clinical and pulmonary manifestations of serologically proven mycoplasma infections were reviewed in 34 patients from 11 families consisting of 30 children and adolescents aged 1 to 18 years, and four parents aged 30 to 41 years (total number of family members = 59:37 children, 22 adults). Twenty-seven of the 37 children had pulmonary involvement (73%). The total infection rate was 58%, and the infection rate in children 81%. The roentgenologic findings in children with pneumonia showed no pathognomonic features. The most common X-ray finding was bronchopneumonia (48%). Pulmonary infiltrates occurred in six children (20%) under four years of age. Three of the children (10%) had severe clinical and/or radiological manifestations. These findings depict a pattern of mycoplasma infection that is different from previous reports, i.e. high pulmonary infection rates in families, the occurrence of pneumonic infiltrations in young children and a quite severe clinical and radiological course in some of the patients.

[First intention treatment with josamycin in primary acute pneumopathies of infectious origin in adults]

In a prospective study 128 community acquired pneumoniae were treated with a macrolide (josamycin) by oral route. Patients improved in 94 p. 100 (113). Complications were as following: 2 deaths, 2 sequels, 3 failures. Authors discuss macrolides effectiveness in acute pneumoniae, particularly pneumococcal ones. They conclude macrolides are a good choice in first intention in acute pneumoniae of adults.

Secondary bacterial infections in children with proved Mycoplasma pneumoniae

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Human ciliated epithelial cells from nasal polyps as an experimental model for Mycoplasma pneumoniae infection

Human ciliated epithelial cells derived from nasal polyps and cultured in a monolayer were studied as an experimental model for Mycoplasma pneumoniae infection. Scanning electron microscopy revealed two types of cultured epithelial cells: one which was covered by microvilli only and another which had microvilli and actively beating cilia. M. pneumoniae adhered to both types of cells, and the adherence followed saturation kinetics as a function of time. Infection of the cells for 20 h resulted in 75% inhibition of their intracellular catalase activity and a 3.5-fold increase in their malonyldialdehyde levels compared with noninfected controls. This indicates the presence of cellular oxidative damage due to M. pneumoniae infection. It is suggested that human nasal ciliated epithelial cells may serve as a representative model for studying M. pneumoniae in relation to its natural host.

The prevalence of ureaplasma, mycoplasma and antibodies against chlamydia group antigen in gynecological outpatients

177 women with an average age of 30 years were investigated for ureaplasma, mycoplasma and for antibodies against the chlamydia group antigen. Specimen of endocervical mucus and catheter specimens of urine were cultured and the ELISA ("enzyme-linked immunosorbent assay") technique applied. In addition the purity class (I to III) of gram-stained vaginal smears was determined. Ureaplasma were isolated from 45.8 and 26.0%, mycoplasma from 9.0 and 7.9% of cervical and urine specimens respectively. The patients were divided into 5 clinical groups. Patients in the first three groups (I-III, inflammatory disorders, bleeding anomalies, benign and malignant neoplasms of the genital tract) showed a significantly (p less than or equal to 0.05) higher colony count of ureaplasma in their urine than patients in the other two groups (IV and V, who had attended the hospital for reproductive problems or for routine examination). There was a clear correlation between the isolation rates of ureaplasma and mycoplasma and the purity classes of the vaginal smears. The rate of isolation increased progressively with class II and III smears. Antibodies against the chlamydia group antigen were detected in about 40% of all sera tested. A very high titer of antibodies reflecting a recent chlamydial infection was found in 11% of the sera tested.

Antigenic mimicry of mammalian intermediate filaments by mycoplasmas

A murine monoclonal antibody raised against Mycoplasma hyorhinis specifically reacted by indirect immunofluorescence with mammalian intermediate filaments. The antibody recognized a related epitope on a 74,000-molecular-weight protein of M. hyorhinis and on components of similar size from other pathogenic mycoplasmas. This defines a shared antigenic structure of interest in autoantibody development during mycoplasmal diseases.

Mycoplasmal pneumonia. Three severe cases of a common infection

Mycoplasma pneumoniae is one of the most common causes of community-acquired pneumonia. Infection is usually self-limited, but fulminant pneumonia and extrapulmonary complications can supervene. Usually, unilateral confluent, patchy, or nodular infiltrates of the lower lobe are seen on roentgenograms. Diagnosis is achieved by isolation of the organism or by serologic methods. Treatment with either erythromycin or tetracycline is effective, although organisms can be recovered during therapy. In the three cases of mycoplasmal pneumonia reported here, infection was resistant to initial therapy but patients recovered when appropriate antimicrobial therapy was instituted.

Clinching the diagnosis--sputum and other specimens in respiratory tract infection

Routine sputum culture in microbiology laboratories is frequently a source of dissatisfaction to microbiologists and clinicians alike. Care should be taken to ensure that the investigations requested are appropriate and that an adequate specimen is collected. Co-operation between the microbiologist and the clinician is required if the laboratory's facilities are to be properly exploited for the etiological diagnosis of respiratory tract infection. In clinical conditions such as lung abscess and atypical pneumonia sputum is not an appropriate specimen for the laboratory to work on and early consideration should be given to obtaining lower respiratory tract secretions free of oropharyngeal contamination.

Role of superoxide anion in host cell injury induced by mycoplasma pneumoniae infection. A study in normal and trisomy 21 cells

The role of Mycoplasma pneumoniae-generated superoxide and hydrogen peroxide in inducing host cell injury was studied in normal and trisomy 21 human cells. As a result of M. pneumoniae infection, catalase activity in infected normal skin fibroblasts and ciliated epithelial cells decreased by 74-77% as compared with uninfected controls. Addition of superoxide dismutase to the infected cultured cells totally prevented the inhibition whereas addition of catalase or catalytically inactivated superoxide dismutase had no protective effect. Trisomy 21 erythrocytes and cultured skin fibroblasts in which CuZn-superoxide dismutase content is 50% greater than in normal cells were infected by M. pneumoniae. The inhibition of catalase activity in these cells was 7-33% and 0-20.5%, respectively, as compared with 65-72% and 48-68% inhibition in normal infected controls. Following M. pneumoniae infection, the levels of malonyldialdehyde, an indicator for membrane lipid peroxidation were raised in trisomy 21 cultured fibroblasts by 10-32% while in normal cells malonyldialdehyde increased by 140-870%. Externally added superoxide dismutase, but not catalase, reduced the extent of lipid peroxidation in normal infected cells. Lactate dehydrogenase release from normal infected cells was time correlated with the increase in their malonyldialdehyde formation. It is suggested that superoxide generated during M. pneumoniae infection is involved in the inhibition of host cell catalase activity. The inactivation of this cellular antioxidative defense mechanism results in progressive oxidative damage to the M. pneumoniae-infected cells.

Immunoglobulin A1 protease activity in strains of Ureaplasma urealyticum

Thirteen serovars of Ureaplasma urealyticum were analyzed for the ability to cleave human IgA. Strains of all of the serovars tested cleaved IgA 1 in the hinge region of the alpha-chain, resulting in intact Fc and monomeric Fab fragments. IgA 1 protease activity was also observed in concentrated cell-free extracts of spent cultivation medium, indicating that the IgA 1 protease was excreted into the medium during growth of the micro-organisms. Five clinical isolates of U. urealyticum obtained from urine, cervix, vagina, amniotic fluid, and synovial fluid were positive for IgA 1 protease activity. No proteolytic activity was observed against human IgA 2, IgG, or IgM. Strains of Mycoplasma fermentans, M. salivarium and seven serovars of M. hominis were negative for IgA 1 protease activity.

Mycoplasma infections of the human urogenital tract with particular reference to non-gonococcal urethritis

The criteria which need to be fulfilled before regarding a microorganism as a cause of non-gonococcal urethritis (NGU) are considered in relation to Mycoplasma hominis, Ureaplasma urealyticum and M. genitalium. There is no evidence to support an aetiological role for M. hominis, but few appropriate investigations have been undertaken. The criteria have been met, for the most part, in the case of U. urealyticum, but further quantitative studies are required. The role of M. genitalium is unknown, but its biological and morphological features and ability to cause genital disease in animals suggest that it may be pathogenic for man. It is emphasized that the criteria for regarding a microorganism as a cause of NGU should also be used where feasible when investigating the infectious aetiology of other genito-urinary conditions.

The adhesins of Mycoplasma gallisepticum and M. pneumoniae

The growth of M. gallisepticum was monitored in regard to their capacity to haemagglutinate. The maximal potential was with cells grown for about 22 h. M. gallisepticum, like M. pneumoniae, possess a Triton shell intracellular filamentous structure which is revealed by exposing the cells to a relatively low concentration of Triton-X100. The adhesin of M. gallisepticum was partially purified on sialoglycopeptide conjugated to Sepharose-4B. The adhesin fraction was primarily composed of one polypeptide of about 75,000 molecular weight.

Inhibition of host cell catalase by Mycoplasma pneumoniae: a possible mechanism for cell injury

This study demonstrates that viable Mycoplasma pneumoniae cells inhibit catalase activity in several types of intact human cells as well as in solution. Human erythrocyte catalase was inhibited up to 72%, and the inhibition of catalase in human cultured skin fibroblasts, lung carcinoma epithelial cells, and ciliated epithelial cells from human nasal polyps ranged between 75 and 80%. UV light-killed mycoplasmas failed to inhibit catalase activity both in intact cells and in vitro. After M. pneumoniae infection of human cultured skin fibroblasts, the level of malonyldialdehyde, an indicator for membrane lipid peroxidation, was 3.5 times higher than in control fibroblasts. Virulent M. pneumoniae completely inhibited catalase activity in solution, whereas the nonvirulent strains had a lesser ability to inhibit catalase activity. These findings suggest that as a result of host cell catalase inhibition by M. pneumoniae, the toxicity of the hydrogen peroxide generated by the microorganism and the affected cell is enhanced, thereby inducing host cell damage.

Mycoplasma hominis septicaemia

Mycoplasma hominis septicaemia occurred in a patient with a malignant lymphoma of lymphoblastic type in leukaemic phase. M hominis was isolated several times from blood cultures with antibody titres against the micro-organism rising to a high level despite severe immunosuppression. M hominis was detected in the blood after subculture of the blood culture bottles despite their macroscopically normal appearance. The patient's pyrexia resolved without treatment with antibiotics effective against M hominis.

Mycoplasma-induced BALB/c 3T3 collagenase is a mammalian enzyme

A collagenase previously reported to accumulate in the medium of cultures of BALB/c 3T3 cells on infection with Mycoplasma orale [Kluve, Merrick, Stanbridge & Gershman (1981) Nature (London) 292, 855-857] was partially purified and characterized. With regard to purification properties, activation, sensitivity to inhibitors and relative molecular mass the enzyme was similar to previously reported vertebrate collagenases, but could not be unequivocally distinguished from bacterial collagenases. With regard to substrate-specificity and reaction products, however, the collagenase was typical of vertebrate collagenases and distinct from bacterial collagenases. Specifically, the enzyme displayed a preference for type III collagen and type I collagen, a somewhat decreased ability to degrade type II collagen, and a very limited ability to degrade type IV collagen. The initial products of the action of the collagenase on type I collagen were characterized as fragments one-quarter and three-quarters of the length of the intact collagen molecule. Because the properties of the collagenase produced by cultures of mycoplasma-infected BALB/c 3T3 cells are those of a mammalian-type (vertebrate-type) enzyme, we have concluded that the collagenase is a product of the mouse (BALB/c 3T3) genome, and is not produced by the mycoplasma. Therefore it appears that infection of BALB/c 3T3 mouse fibroblasts with Mycoplasma orale induces the mouse cells to produce and secrete collagenase.

New York City medium for enhanced recovery of Mycoplasma pneumoniae from clinical specimens

Modified New York City (MNYC) medium and PPLO medium without methylene blue (PPLO agar) were compared for their ability to support the growth of Mycoplasma pneumoniae from clinical specimens. Pharyngeal specimens were collected from 1,070 college students who visited the Syracuse University Student Health Center. Of these patients, 623 were symptomatic for respiratory infection, and the remaining 447 were asymptomatic for respiratory illness. Throat swabs were inoculated into PPLO broths, and these broths were subcultured onto MNYC medium and PPLO agar after 3 and 14 days of incubation. A total of 222 (20.7%) clinical isolates of M. pneumoniae were recovered on these solid media, with the majority of the isolates (196) recovered from symptomatic patients. All isolates grew on MNYC medium, whereas five isolates failed to grow on PPLO agar. All isolates of M. pneumoniae recovered from symptomatic patients were detected on MNYC medium within 1 to 5 days of incubation, whereas 5 to 7 days of incubation were required before mycoplasmal growth was detected on PPLO agar. Over 86% of these mycoplasma isolates were detected on MNYC medium within 3 days of incubation and before the detection of any mycoplasmal growth on PPLO agar. A similar pattern of recovery times was observed for mycoplasmas isolated from asymptomatic patients. The results of this study have shown that MNYC medium is better than PPLO agar in supporting the rapid growth of M. pneumoniae from clinical specimens after 72-h blind subculture in PPLO glucose broth.

Septicaemia in a renal transplant patient due to Mycoplasma hominis

Opportunistic infections are an important cause of mortality in transplant patients. Here we report a case of Mycoplasma hominis septicaemia in a renal transplant patient that was successfully treated with doxycycline.

Host discrimination of Mycoplasma pneumoniae proteinaceous immunogens

The immune response of experimentally infected hamsters and human patients to Mycoplasma pneumoniae was examined by radioimmunoprecipation in conjunction with gel electrophoresis and fluorography. Both intrinsically and extrinsically labeled mycoplasma proteins were coincubated with acute and convalescent sera in a radioimmunoprecipitation assay. Two M. pneumoniae proteins were selectively precipitated by convalescent sera. These predominant immunogens were trypsin-sensitive, antibody-accessible surface proteins that co-migrate on polyacrylamide gels with proteins P1 and P2, which were previously implicated by us as mediators of cytadsorption. Anti-M. pneumoniae antiserum did not precipitate radiolabeled antigens derived from Mycoplasma orale or Mycoplasma salivarium. These data indicate that M. pneumoniae infection stimulates a specific and highly targeted host antibody response to key proteinaceous immunogens.

Measurement of antibody to Ureaplasma urealyticum by an enzyme-linked immunosorbent assay and detection of antibody responses in patients with nongonococcal urethritis

The optimum conditions for the detection of human immunoglobulin G (IgG), IgM, and IgA antibodies to Ureaplasma urealyticum by an enzyme-linked immunosorbent assay (ELISA) were established by using a cell lysate antigen and commercially available alkaline phosphatase conjugates. No significant cross-reactions were observed among rabbit antisera to a variety of mycoplasmas of human origin and ureaplasma antigen, thus demonstrating the specificity of the ELISA. All human sera were assayed at a 1:200 dilution. Antigen was used at 20 mug of protein/ml and conjugates were diluted 1:500. Presence of IgG antibody to U. urealyticum was significantly associated with isolation of U. urealyticum (P < 0.001) in 110 women. Seventeen acute-phase and 19 convalescent-phase sera from male nongonococcal urethritis (NGU) patients were tested for the presence of antibody by both the metabolism inhibition assay and by ELISA, with overall agreements of 82 and 95% for acute- and convalescent-phase sera, respectively. Serum antibody responses were demonstrated to selected serotypes in the metabolism inhibition test, but the response as measured by the ELISA was independent of the serotype of the antigen used. Serum antibody levels in NGU patients were significantly higher (P < 0.002) than the normal serum standard in the IgG, IgM, and IgA classes. Additionally, the magnitude of change between acute- and convalescent-phase sera was greater for NGU patients than for normal asymptomatic ureaplasma-positive male controls. A significant change in antibody levels of one or more antibody classes was detected for 12 of 18 (67%) NGU patients by ELISA. Ten of the 12 (83%) individuals had a change in the IgM class, which is suggestive of an active infectious process. The ELISA is advantageous in that it requires only a single serotype antigen, uses one serum dilution, is class specific, and allows quantitative detection of differences between acute- and convalescent-phase sera.

Reactive arthritis--infectious agents and genetic susceptibility in the pathogenesis of sero-negative arthritis

In this review we discuss the role of genetic and infectious factors in the aetiology of ‘reactive’ arthritis. Two broad categories of reactive arthritis are considered—the sero-negative HLA B27 related spondarthritides, and a miscellaneous group of reactive arthritides occuring after bacterial infection but which are not HLA B27 related.

Acute encephalitis of viral origin

75 patients with acute encephalitis of confirmed or suggestive viral or virus-like etiology showed a predominance of herpes simplex virus (HSV) as an etiological agent (13.3-32.0%) in all age groups without seasonal variation and increasing in number during years. Mumps, occurring mainly in female patients, was next in order and thereafter coxsackievirus B, varicella-zoster, and adenoviruses, followed by multiple coincident infections, and a large number of occasional agents. HSV seems to have displaced tick-borne encephalitis virus as the major cause of acute encephalitis in Finland. Pregnancy appeared to increase susceptibility to HSV encephalitis. The outcome was associated with the etiological agent in the first hand, HSV and nonviral microbes appeared unfavourable, but also with the clinical symptomatology, particularly altered consciousness, mental symptoms and focal neurological signs. The need for exact and rapid diagnosis in all cases of acute encephalitis is underlined in view of the possibility of specific therapy.

Mycoplasma hominis septicemia

We report a case of Mycoplasma hominis septicemia in a patient with chronic lymphocytic leukemia and prostatic obstruction. Signs of sepsis followed urinary catheterization, and M. hominis was recovered repeatedly from blood, urine, and pleural fluid. Detection in blood was accomplished by routine subculture from grossly negative blood culture bottles.

Progressive heart failure and death associated with Mycoplasma pneumoniae pneumonia

A case of progressive CHF and death associated with serologically confirmed Mycoplasma pneumoniae pneumonia in a previously healthy man is described. The association between the organism and significant cardiac or pericardial dysfunction discussed, the literature reviewed, and speculation made as to the underlying pathophysiologic mechanisms.

Expanded serotyping scheme for Ureaplasma urealyticum strains isolated from humans

For the last decade the serological heterogeneity of strains of Ureaplasma urealyticum isolated from humans has been represented by eight serotypes. We have identified two additional serotypes, strains Vancouver and Western. Using a modified metabolic inhibition test and a colony indirect epifluorescence method, we tested antisera to the above 10 types against the 11 members of the independent Lin-Kass classification. Four of the latter, K2, U24, U26, and U38, showed unique specificities; these were confirmed by reciprocal testing with antisera prepared against the respective strains. With the addition of these strains, the serotyping scheme now has 14 members. Since this expanded classification allows greater discrimination between strains, it will allow also for their future characterization. It provides, in addition, a potentially more effective epidemiological tool.

Isolation of mycoplasmas and bacteria from the blood of postpartum women

Mycoplasmas and/or bacteria were recovered from the blood cultures of 26 (20.8%) of 125 febrile postpartum women. Genital mycoplasmas were recovered from 16 (12.8%) of the 125 febrile women and from none of 60 afebrile postpartum women (p less than 0.005). The presence of mycoplasmaemia was associated with a young age, primigravidity, and nulliparity. The isolation of organisms from the blood was also associated with fever during labor, internal monitor use, and a cesarean delivery.