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Spectrum of clinical and radiographic findings in pediatric mycoplasma pneumonia.

Clinical symptoms in mycoplasma infection are nonspecific. Pulmonary involvement may be widespread or focal and segmental and is accompanied by signs including rales, rhonchi, and decreased breath sounds. Although manifestations of mycoplasma infection are usually confined to the respiratory tract, a wide variety of extrarespiratory manifestations can also occur, including more severe associated diseases such as myocarditis, acute disseminated encephalomyelitis, and cerebral arteriovenous occlusion. The radiographic findings in mycoplasma pneumonia are also nonspecific and in some cases closely resemble those seen in children with viral infections of the lower respiratory tract. Focal reticulonodular opacification confined to a single lobe is a radiographic pattern that seems to be more closely associated with mycoplasma infection than with other types of pediatric respiratory illnesses, and the diagnosis of mycoplasma pneumonia should be considered whenever focal or bilateral reticulonodular opacification is seen. Hazy or ground-glass consolidations frequently occur, but dense homogeneous consolidations like those seen with bacterial pneumonias are uncommon. Atelectasis or transient pseudoconsolidations due to confluent interstitial shadows are often seen. Radiographic findings alone are not sufficient for the definitive diagnosis of mycoplasma pneumonia, but in combination with clinical findings they can significantly improve the accuracy of diagnosis in this disease.

Adolescent↗

[Role of Mycoplasma pneumoniae in the etiology of acute respiratory infections in Ribeirao Preto, Sao Paulo, Brazil].

Mycoplasma pneumoniae isolation was attempted in respiratory fluids from 64 patients with respiratory infection Complement fixation test (CF) and counterimmunoelectrophoresis (CIE) were used for Mycoplasma antibody detection using the patient sera. Mycoplasma pneumoniae was not isolated. Serologic diagnosis were positives in 3.1% (2/64) by CF test and 1.6% (1/64) by CIE. Serologic tests done in 200 health controls showed 4% (8/200) positives by CIE and 1% (2/200) by CF. The results showed differences in sensitivity among the serologic tests. CF seems to be more indicated for Mycoplasma infection diagnosis while, CIE could be used for Mycoplasmas serosurveys. The prevalence of Mycoplasma pneumoniae infections was low (3.1%) in the 64 patients during our study period.

Acute Disease↗

Mechanisms of drug resistance in Mycoplasma pneumoniae.

Mycoplasma pneumoniae is a pathogenic mycoplasma responsible for respiratory tract infections in humans, occurring worldwide in children and adults. This review briefly focuses on its antibiotic susceptibility profile and on the development of acquired resistance for this microorganism. The lack of a cell wall in mycoplasmas makes them intrinsically resistant to beta-lactams and to all antimicrobials which target the cell wall. Intrinsic resistance related to specific mycoplasma species concerns essentially the acrolide-lincosamide-streptogramin-ketolide (MLSK) antibiotic group. M. pneumoniae is susceptible to all MLSK antibiotics, except to lincomycin. Among the three antibiotic classes used for the treatment of mycoplasmal infections including tetracyclines, MLSK group, and fluoroquinolones, macrolides and related antibiotics are the drug of choice for respiratory infections caused by M. pneumoniae. Both target alterations and efflux mechanisms implicated in acquired antibiotic resistance have been described in mycoplasmas either by genetic mutation or transfer of new genes carried by transposons. At present, M. pneumoniae remains greatly susceptible to antibiotics, but as this mycoplasma is difficult to isolate, the number of clinical strains tested is limited and the occurrence of acquired resistance not well documented. However some strains having acquired resistance to MLSK have been decribed in vivo and erythromycin-resistant isolates are spreading now in Japan. To date, no clinical isolates resistant to fluoroquinolones or tetracyclines have been described in the literature, but some strains having acquired resistance to both classes have been selected in vitro. Molecular diagnosis of this acquired resistance has been related to target alterations, in ribosome for macrolides and tetracyclines, or in topoisomerase II genes for fluoroquinolones.

Adult↗

Isolation of genital mycoplasmas from blood of febrile obstetrical-gynecologic patients and neonates.

In a prospective study, 1156 blood specimens collected from hospitalized febrile obstetrical-gynecologic patients and neonates with suspected sepsis, were inoculated into a conventional biphasic culture medium, Castaneda S and cultures incubated aerobically. 15-24 h later the broth cultures were subcultured to specific media for detection of mycoplasmas. Genital mycoplasmas were isolated in 15 samples (taken from 8 women) and in 2 from 1 neonate. Mycoplasmas and members of the family Enterobacteriaceae were the most frequent significant bacteria isolated from adult specimens. Mycoplasma isolations were associated with either postpartum or postabortum febrile infections in women. Four of the neonates, whose mothers were infected, showed respiratory distress at birth; 1 of them had mycoplasmas in the blood. All febrile states in obstetrical or gynecological patients, and in neonates, should routinely lead to blood cultures for detection of mycoplasmas and ureaplasmas.

Adult↗

Mycoplasma viruses.

Unlike bacterial viruses that infect cells bounded by a cell wall, mycoplasma viruses have evolved to enter and propagate in mycoplasma cells bounded only by a single lipid-protein cell membrane. In addition, mycoplasmas have the smallest amount of genetic information of any known cells, so their complexity is constrained by a limited genetic coding capacity. As a consequence of these host cell differences, mycoplasma viruses have been found to have a variety of structures and replication strategies which are different from those of the bacterial viruses. This article is a critical review of mycoplasma viruses infecting the genera Acholeplasma, Spiroplasma, and Mycoplasma; included are data on classification, morphology and structure, biological and physical properties, chemical composition, and productive and lysogenic replication cycles.

Acholeplasma↗

Adaptation of Mycoplasma hominis to an obligate parasitic existence in monkey kidney cell culture (BSC-1).

During attempts to eliminate Mycoplasma hominis from a monkey kidney BSC-1 cell line with antibiotics, the mycoplasmas were isolated repeatedly. However, the organisms ultimately failed to grow on medium although electron microscopy confirmed that the cell culture still contained mycoplasmas. Thus, the mycoplasma had adapted to an environment in which viable cells were required for growth. Budding mycoplasmas which are indicative of replication were seen associated with viable cells extracellularly. Moreover, structures resembling cycoplasmas were observed budding from the cells which suggests that the mycoplasmas replicate within the cells and are similar to many viruses in their manner of release from the cells.

Adaptation, Biological↗

Alterations in monoclonal antibody affinity and antigenic receptor site expression on mycoplasma-infected human colorectal cancer cells.

The affinity of MoAb CO 17-1A and expression of its antigenic target were studied on uninfected and mycoplasma-infected colorectal cancer cell lines SW 1116 and SW 948. Binding of 125I-labeled CO 17-1A to SW 1116 cells was quantified at 37 degrees C by determination of the affinity constant (Ka) and the number of antigenic receptor sites (r) per cell using Scatchard plots. When mycoplasma-free SW 1116 cells were used as targets, Ka was 0.92 +/- 0.06 x 10(8) M-1 and r = 1.32 +/- 0.14 x 10(6) at 37 degrees C. One batch of unspeciated, mycoplasma-infected SW 116 cells had reduced affinity and a decreased number of antigenic receptor sites per cell for 125I-labeled 17-1A, while another batch of infected SW 1116 cells had a 4- to 5-fold increase in r and diminished Ka for the antibody compared with uninfected cells. When unspeciated, mycoplasma-infected SW 948 cells were exposed to 125I-labeled 17-1A and the data subjected to Scatchard analysis, the affinity of the antibody deviated markedly from linearity and rendered analysis for Ka and r meaningless. These data indicate that mycoplasma infection can produce variable effects on the cellular expression of antigenic receptor sites and the affinity of antibody for its target, and emphasize the importance of using mycoplasma-free cell lines in studies of these parameters.

Animals↗

The upper and lower respiratory tracts differ in their requirement of IFN-gamma and IL-4 in controlling respiratory mycoplasma infection and disease.

The purpose of this study is to evaluate the significance of IFN-gamma and IL-4 production in controlling mycoplasma infection and the pathogenesis of disease in the upper and lower respiratory tract. By using IFN-gamma knockout and IL-4 knockout BALB/c mice, we were able to study the contribution of these cytokines in the development of pathogenesis and/or protection in response to mycoplasma respiratory infection, in both the upper and lower respiratory tracts. The loss of either IFN-gamma or IL-4 does not affect disease pathogenesis or mycoplasma organism numbers in the upper respiratory tract. However, in the absence of IL-4, the nasal passages developed a compensatory immune response, characterized by higher numbers of macrophages and CD8(+) T cells, which may be masking detrimental effects due to IL-4 deficiency. This is in contrast to the lower respiratory tract, where the loss of IFN-gamma, but not IL-4, leads to higher mycoplasma numbers and increased disease severity. The loss of IFN-gamma impacted the innate immune system's ability to effectively clear mycoplasma, as the number of organisms was higher by day 3 postinfection. This higher organism burden most likely impacted disease pathogenesis; however, the development of Th2 cell-mediated adaptive immune response most likely contributed to lesion severity at later time points during infection. Our studies demonstrate that the upper and lower respiratory tracts are separate and distinct in their cytokine requirements for generating immunity against mycoplasma infection.

Animals↗

Phenotypic variation of Mycoplasma iowae surface antigen.

The diseases caused by mycoplasmas are generally chronic and persistent and apparently occur notwithstanding a host immune response. The ability to evade the host immune response is facilitated by phenotypic variation in the mycoplasma surface components. The avian mycoplasmas Mycoplasma gallisepticum and Mycoplasma synoviae have both been previously described to be able to switch their surface antigens, and recent evidence indicates that M. gallisepticum could switch surface antigens under natural conditions in vivo. In this work we present data to support that Mycoplasma iowae is also capable of phenotypic variation as detected by reactions with the monoclonal antibody MAb MI1 on colony immunoblots. This phenomenon is suggested to occur spontaneously or in response to normal serum and tissue components and may play an important role in the evasion of the host immune response.

Animals↗

[Mechanisms of genetic instability of mollicutes (mycoplasma)].

Mollicutes are unique microorganisms characterized by a great extent for the reduction in genetic material, which retained the capability of independent division on acellular nutrient media. Phenotypically mycoplasmas differed from other bacteria by their small size and lack of a cell wall (mollis, soft; cutis, skin). High dependence on metabolism components utilized in the cultivation medium and high metabolic plasticity due to the absence of many genome regulatory elements make mycoplasmas perfect parasites for cells of the eukaryotic origin. The ability of these microorganisms to pass through host cells and their assumed participation in AIDS activation facilitate the study of mycoplasma pathogenesis. Another important feature of mycoplasmas, which is expressed during their interaction with a macroorganism, is their ability to escape from the immune response of a host due to surface antigen variation. These adaptation capacities of mycoplasmas ensuring their life in various biological niches, given a limited genome and the direct metabolic dependence on an environment, cannot be adequately explained at present. In this review, we attempted to collect and systematize data that contribute to our understanding of the important feature of mycoplasmas, genetic instability, which may underlie many of their adaptive responses.

Antigens, Bacterial↗

Comparative study of the prevalence of mycoplasma in males with non specific urethritis.

Three groups of males were examined for the study of Mycoplasma in the aetiology of Non-specific Urethritis. From a group of 120 men suffering from N.S.U. (group I) have been isolated from the genital tract "large-colony" and T-strain mycoplasma in proportion 22.5% and 68.3% respectively. Socially this group represent the lower classes of the population. From another group of 165 male students suffering also from N.S.U. (group II) have been isolated from the genital tract "large-colony" and T-strain mycoplasma in proportion 25.4% and 58.1% respectively. This group was of higher social and hygienic standards. In contrast in a control group of 70 medical students without urethritis the range was for the "large-colony" 8.5% only and for the T-strain 21.4%. Socially, this group corresponded closely to the Group II. In this study a significant association of T-strain mycoplasma with N.S.U. has been found. Urethral specimens were obtained from all the men by the same method. No statistically significant difference in the isolation rate of Mycoplasma was seen, between Group I which represents a relatively low social and hygienic level and Group II which represents higher social and hygienic standards. It is interesting to note that the percentage of control healthy group (group III) yielding T-strain mycoplasma was lower and no similar to that recorded in previous investigations.

Adult↗

[Participation of Mycoplasmas in oncogenesis (author's transl)].

The conclusions drawn from the presented data are in agreement with previously issued opinions of the author. Mycoplasmas are, synergistically with other factors, esseential and obligatory for oncogenesis. Distince biotypes of Mycoplasmas from different types of tumors could not be isolated. Mycoplasmas possess the ability to induce various tumors, without regard to their origin, either from tumors and fetuses. It is concludet that Mycoplasmas are infectious agents specific for tumor induction in general, but not for a distinct type. The conviction, presented already in 1948, tthat no malignant tumor occurs without the presence of Mycoplasmas, but in contrast, that numerous infections by Mycoplasmas do not provoke the manifestation of malignent tumors, is maintained.

Animals↗

[T(H1) and T(H2) cells in children with mycoplasma pneumonia].

OBJECTIVE: To Study T lymphocyte subsets, including T(H1) and T(H2) cells in peripheral blood mononuclear cells (PBMC) of children with mycoplasma pneumonia, understand immunopathogenesis and explore the possibility of immunotherapy of patients with mycoplasma pneumonia. METHODS: Fresh peripheral blood samples of patients from two groups, group 1, mycoplasma pneumonia (MP) group (35 cases, 15 males and 20 females, age range 3 - 13 years, mean 9 years), and control group consisted of 28 healthy children (14 males and 14 females, age range 3 - 12 years, mean 7 years) were treated and run through the flow cytometry. The data were obtained by using Simultest IMK-Lymphocyte software and the percentage of CD(3)(+), CD(3)(+)CD(4)(+), CD(3)(+)CD(8)(+), CD(3)(-)CD(19)(+) and CD(3)(-)CD(16 + 56)(+) cells were counted. The percentage of T(H1) and T(H2) cells were gained through determination of intracellular cytokines IFN-gamma or IL-4 in CD(4)(+) cells by flow cytometry. The 35 patients with MP were hospitalized at our hospital. In addition to fever and cough, all the patents had abnormal X-ray findings and/or moist rale on auscultation of the lungs. The IgM antibody to Mycoplasma pneumoniae was positive in each patient. Immunoglobulins were measured, and PPD skin tests were performed in 30 out of the 35 patients with MP. T test and rank sum test by SPSS FOR WINDOWS 10.0 was used for statistical analysis. RESULTS: The percentage of CD(3)(+) and CD(4)(+) T lymphocyte was 68.00 +/- 6.66 and 37.86 +/- 5.84, respectively, in MP group, and 63.71 +/- 7.92 and 34.54 +/- 6.23 in control group (P < 0.05). The percentage of T(H1) cells was 14.13 +/- 8.46 in patients and 20.77 +/- 6.89 in normal control group (P = 0.001). The percentage of NK cells was 15.57 +/- 12.16 and 20.39 +/- 9.64 in MP and control group (P < 0.01). The ratio of T(H1)/T(H2) in MP group was lower than that in control group (P < 0.05). However the percentage of CD(8), T(H2), B cells and CD(4)/CD(8) had no difference between the MP and control groups. The levels of IgG, IgA, and IgM in serum were normal in most of patients except for a few patients who had elevated IgA and IgM levels. The PPD skin tests were negative in 30 out of 35 patients. CONCLUSION: In this study a higher percentage of CD(3)(+), CD(4)(+) T lymphocyte and lower percentage of T(H1), NK cells in PBMC of patients with mycoplasma pneumonia were found. The ratio of T(H1) and T(H2) cells in patients was also lower. None of thirty patients had positive PPD skin tests. Unbalanced cell-mediated immunity with a tendency toward T(H2) existed in patients with MP. Therefore, immunomodulators may be useful in treatment of mycoplasma pneumonia.

Adolescent↗

[Prevalence of Mycoplasma orale as a contaminant of cell cultures in Argentina].

Over a period of 4 years 200 cell cultures were analysed for the presence of mycoplasma. Cultures were established cell lines from different origins, namely monkey, mouse and human, hybrid cell cultures and primary cultures. The cultures belonged to various research and industrial laboratories located in different areas of the country. Seventy per cent of investigated cultures were found to be contaminated with mycoplasma using a DNA fluorescent stain. Fifty cultures, selected at random out of the contaminated cultures, were further investigated to identify the prevalent serotype. For that purpose immunofluorescent reactions were performed using immune sera raised against several mycoplasma strains routinely found among contaminated cultures. Forty one cultures were contaminated with a single type of mycoplasma, whereas in the remaining nine, two or even three serotypes were detected. Mycoplasma orale II contaminated 40% of single infected cultures, followed by M. hyorhinis and A. laidlawii-A (12% each), M. arginini (5%), M. orale III (8%), A. laidlawii-B (2%). We were unable to serotype the remaining positive cultures, because of the lack of a full battery of immune sera against all known serotypes. The prevalence of M. orale in mycoplasma contaminated cultures thus far tested, indicates that human handling would be the main source of infection. This situation could be modified by avoiding mouth pipetting and adopting good microbiological techniques.

Acholeplasma↗

Prolonged hyperthermia eliminates mycoplasma from cultured human and rat brain tumor cell lines.

Mycoplasma infection of mammalian cells in culture is a common occurrence that can affect the results of experimental protocols. Current methods of eliminating mycoplasma from cell cultures are usually tedious, time-consuming, and sometimes unsuccessful. In the present study, four cultured brain tumor cell lines (human U-251 MG, U-87 MG, SF-126, and rat 9L) were heavily contaminated with Mycoplasma orale. Heating the cultures to 41 degrees C for at least 96 h eliminated the contamination for up to 7 months, the maximum period of observation. The time chosen to assay for the presence of mycoplasma in cultures was critical: in some cultures heated for less than 96 h that initially appeared to be free of contamination, mycoplasma began to appear after 2 weeks. Heat-treated cells grew at the same rate as unheated control cells. Infected cells were more sensitive to X rays than uncontaminated cells, but the sensitivity reverted to normal after mycoplasma was eliminated by hyperthermia. The heating method does not require a cell cloning procedure or the use of exogenous materials. Treated cell cultures exhibit normal growth and radiation sensitivity, and the technique seems to be reliable and efficient.

Animals↗

[Elimination of mycoplasmas from cultured human cell lines utilizing a combination of two antibiotics, quinolone and a pleuromutilin derivative].

Forty three cultured human cell lines were treated with a combination of 2 antibiotics to eliminate contaminant mycoplasmas. One course of treatment was composed of consecutive 3 or 4 cycles. Each cycle grew cells in BM-1 (pleuromutilin derivative; Boehringer Mannheim) containing medium (10 micrograms BM-1/ml culture) for 3 days, alternating with MC-210 (quinolone; Dainihon Pharmaceutical) containing medium (0.625 micrograms MC-210/ml culture) for 4 days. No treatment failure was encountered with this procedure. Before treatments, 18 (90%) of 20 cell line samples were contaminated with mycoplasma, as tested by DNA hybridization method (MYCOPLASMA T.C. RAPID DETECTION SYSTEM; Gen-Probe Inc.). Out of 43 cell lines treated, 7 were reduced in growth and dropped out. Among the other 36 cell lines, 27 became negative, 5 borderline and 4 slightly positive to the mycoplasma detection. All of the latter 9 cell lines, treated with one more similar course, found to be free from mycoplasma. Six of the dropout lines were cured of mycoplasma by a second treatment, under modified culture conditions. The last cell line (NATO) was successfully treated with another lot of FCS. Thus, the procedure proved successful even in treating promiscuously infected cell lines.

Anti-Bacterial Agents↗

[Incidence and quantification of mycoplasma in saliva in patients with periodontal disease and subjects with healthy gingiva].

The ecological niche of oral mycoplasmas are both gingival pockets in patients suffering periodontitis (PP) and gingival sulci in individuals with healthy gingiva (HG). The mycoplasmas migrate from these anatomical sites to the saliva and to entire oral cavity. The purpose of this report was to examine whether differences exist in the incidence and concentration of mycoplasma as determined in the saliva of thirty (30) PP and fifty (50) individuals with HG. Saliva samples were obtained from both groups, with capillary tubes and cotton swabs, and used for mycoplasma isolation and quantification. The methods employed were those recommended by the Centers for Diseases Control (CDC Atlanta, Georgia). The results showed an 80% mycoplasma incidence in group PP and 50% HG, with the following concentrations: 5.0 x 10(3) to 8.0 x 10(6) Colony Forming Units/ml (CFU/ml) in PP, and 3.0 x 10(3) to 4.5 x 10(4) UFC/ml in the HG (P less than 0.001). We conclude the both mycoplasma incidence and concentration were higher in PP than in HG individuals.

Adolescent↗

[Induction of interleukins by mycoplasma in culture of human mononuclear leukocytes].

Mycoplasma shows a variety of effects on immune system, including the activation of macrophage, the increase in T cell cytotoxicity, and the enhancement of the proliferation and maturation of B cells, etc. As it is well known that many cytokines regulate the immune system, it is interesting to examine whether or not human peripheral blood mononuclear cells (PBMC) produce interleukin (IL) in response to mycoplasmas. In the present study, human PMBC were incubated with 7 species of mycoplasmas for 48 hours, and IL-1 beta, IL-2 and IL-6 activities in the supernatants were determined by ELISA. All the species of mycoplasmas were able to induce IL-1 beta and IL-6, although IL-2 was induced only by M. pneumoniae. These results suggest that the influence of mycoplasma infection on immune system may be partly due to the interleukins induced by mycoplasmas.

Humans↗