Acquired immunity to Mycoplasma pneumoniae. Pneumonia in hamsters

An inactivated Mycoplasma pneumoniae vaccine was prepared from a culture in a liquid medium supplemented with water extract of egg yolk. Vaccinated Syrian hamsters were exposed to virulent M. pneumoniae aerosol and were examined for the retention of mycoplasmas and for histopathological changes in the respiratory tracts. When a vaccine prepared with strain FH was administered intramuscularly or by inhalation in aerosol, no significant resistance was shown with respect to mycoplasma proliferation. An increased resistance, however, was observed when an aluminium phosphate-adsorbed vaccine, and when a plain vaccine (although to a lesser degree) prepared with hamster 24-passaged strain FH, was administered intramuscularly. Histopathologically, lung lesions were markedly suppressed in groups showing high resistance. A correlation between the serum antibody titer and the resistance to infection was observed. Hamsters which received a hyperimmune rabbit antiserum intracordally showed a high resistance to M. pneumoniae infection. The suppression of histopathological changes also coincided with high complement-fixing antibody titers of either actively or passively immunized hamster serum. The results suggest that humoral immunity plays an important role in resistance to M. pneumoniae pneumonia in hamsters.     

Decreased Interleukin-10 Responses in Children with Severe Mycoplasma pneumoniae Pneumonia

Several cytokines may play roles in the immunological pathogenesis of mycoplasmal pneumonia caused by Mycoplasma pneumoniae. In this study, we investigated serum cytokine profiles in children with mycoplasmal pneumonia. The serum levels of interleukin (IL)-8, IL-10, and IL-18 were examined using ELISA kits in 34 patients with M. pneumoniae infection (Group 1, 11 with severe mycoplasmal pneumonia; Group 2, 13 with mild mycoplasmal pneumonia; Group 3, 10 with asthma) and 32 age-matched, non-infected controls. The serum levels of IL-8, IL-10, and IL-18 increased significantly in patients with mycoplasmal pneumonia compared with those in controls (P<0.01). The serum levels of IL-10 decreased significantly in Group 1 compared with those in Group 2 (P<0.01). The serum levels of IL-18 increased significantly in Group 1 compared with those in Group 2 (P<0.01). The serum levels of IL-10 and IL-18 decreased significantly in 10 M. pneumoniae-infected patients with asthma compared with those in 24 M. pneumoniae-infected patients without asthma (P<0.01). We examined the level of interleukins (IL-8, IL-10 and IL-18) after the patients started therapy. The data showed that IL-18 were lower after therapy (P<0.01). Collectively, our data suggested that these cytokines may be involved in the pathogenesis of mycoplasmal pneumonia.     

Role of Humoral Antibodies in Resistance to Mycoplasma pneumoniae Pneumonia in Hamsters

Golden Syrian hamsters adoptively immunized with hyperimmune Mycoplasma pneumoniae rabbit antiserum, immunoglobulin (Ig) M-rich (IgM) fraction, IgG-rich (IgG) fraction, antiserum absorbed with either killed M. pneumoniae or killed Staphylococcus aureus organisms, or antiserum treated with 2-mercaptoethanol (2-ME) were examined for resistance against aerosol infection with virulent M. pneumoniae. Significant resistance to the establishment of infection in the respiratory tract was shown in hamsters pretreated with the untreated antiserum, IgG fraction or 2-ME-treated antiserum, whereas animals pretreated with the IgM fraction and the antisera absorbed with M. pneumoniae or S. aureus organisms were not significantly resistant. Histopathologically, lung lesions were markedly suppressed in animals with high resistance, but were typically pneumonic in animals with low or no resistance. The efficacy of adoptively administered serum preparations was closely related to their antibody titers. The results indicate that humoral antibody plays an important role in protection against experimental M. pneumoniae pneumonia in hamsters, although the participation of the cell-mediated immune response was not determined.     

探讨接种时间和剂量对小鼠肺炎支原体肺炎模型建立的影响

目的 用不同时间和剂量建立BALB/c小鼠的肺炎支原体肺部感染模型,探索小鼠急性肺炎支原体感染的过程.方法 BALB/c小鼠随机分为Ⅰ、Ⅱ两组,Ⅰ组在0、1、2 d滴鼻接种肺炎支原体菌液3次,Ⅱ组在0 d滴鼻接种小剂量肺炎支原体菌液1次后于8、9 d再接种和Ⅰ组相同的肺炎支原体菌液2次,均设立不同剂量、批次的生理盐水对照组.全部实验动物在3～18 d内分批处死.所有小鼠均取肺组织做病理切片.以组织病理学评分来确定小鼠的肺部炎症反应程度.取肺组织匀浆及肺泡灌洗液(BALF)进行肺炎支原体培养做病原学检测.结果 接种后实验动物全部存活无死亡.实验组动物均出现不同程度的肺炎支原体肺炎样病理改变,组织病理学评分为1.5～14.3分,分别于第5、6天和第11天达到最高,平均分为4.9分;Ⅰ组实验组动物多呈轻、中度改变,Ⅱ组实验组动物多呈中、重度改变.所有实验组动物肺组织匀浆及BALF的肺炎支原体培养在接种后1月内先后出现阳性结果.对照组动物未出现明显肺部炎症改变,组织病理学评分为0～1分,肺炎支原体培养为阴性.结论 成功建立BALB/c小鼠的肺部肺炎支原体感染模型;组织病理学评分方法可用以评价肺部炎症反应的严重程度;不同接种时间和剂量所致的病变程度不同.     

Role of the Mycoplasma pneumoniae/Interleukin-8/Neutrophil Axis in the Pathogenesis of Pneumonia

Neutrophil infiltration is the characteristic pathological feature of M. pneumoniae pneumonia (MPP). This study aimed to explore the associations among neutrophil activity, clinical presentation, and role of the M. pneumoniae/interleukin-8 (IL-8)/neutrophil axis in the pathogenesis of MPP. A total of 42 patients with MPP were prospectively enrolled in the study. Neutrophil activity, including matrix metalloproteinase-9 (MMP-9), myeloperoxidase (MPO), and neutrophil elastase (NE), were measured. Clinical information was collected for all patients and control group. In vitro, IL-8 production was measured at different time points after M. pneumoniae infection of bronchial epithelial cells, and neutrophil activity was analyzed after IL-8 stimulation. The percentage of neutrophil in the bronchoalveolar lavage fluid was higher in the group of patients with high levels of M. pneumoniae DNA than in those with low levels of M. pneumoniae DNA (P < 0.05). IL-8, MMP-9, and NE in patients with MPP significantly increased compared with controls and decreased after treatment (P < 0.05). MPO and MMP-9 were associated with duration of fever (r = 0.332, P < 0.05) and length of stay (r = 0.342, P < 0.05), respectively. In vitro, M. pneumoniae induced IL-8 production by bronchial epithelial cells in a time dependent manner. MPO, MMP-9 and NE production by neutrophils significantly increased compared with medium controls after IL-8 stimulation. In summary, the M. pneumoniae/IL-8/neutrophil axis likely plays a vital role in the pathogenesis of MPP.     

Nonstationary Heart Rate Variability in Respiratory Tests

A new method was proposed for processing a nonstationary heart rate by using frequency-modulated signals rather than amplitude-modulated signals equally spaced over several points of time as in the conventional method. A frequency-modulated signal is a set of identical Gaussian peaks that coincide with the true time points of heart beats. A continuous wavelet transform was used to quantitatively describe the heart rhythm signal. A test with controlled breathing was performed as an example and included three consecutive stages: rest, rhythmic breathing at a specified frequency, and exhalation. Tachograms recorded during the breath test was found to be a nonstationary signal with the alternation of peaks of different spectral ranges. A system of quantitative parameters was developed to describe the dynamics of changes in the spectral properties of the tachogram in transitional areas. A static clustering by the effect of the respiratory test and a dynamic clustering in order to identify the time points when the autonomic nervous system is stressed were performed for all subjects. The article discusses the prospects of using the method as a means to analyze the transient effects in various functional tests and as biofeedback that would help to change the heart rhythm.     

中西医结合治疗成人支原体肺炎的临床评价

为评价中西医结合治疗成人支原体肺炎的疗效。对我院2009~2010年住院的60例支原体肺炎患者的临床资料进行回顾性分析,通过患者体温、临床表现及平均住院日变化比较中西医结合治疗与单用阿奇霉素治疗对支原体肺炎的疗效。用药后治疗组的退热时间、咳嗽消失时间、肺部啰音消失时间均较对照组明显缩短,差异显著（P〈0.01或P〈0.05）。平均住院日也明显缩短,但无统计学差异（P〉0.05）。治疗组的治愈及显效病例高于单纯西药组,胃肠道不良反应低。中西医结合治疗成人支原体肺炎疗效较好,较单纯应用阿奇霉素治疗能更快改善症状。     

Pneumonia due to mycoplasma in gnotobiotic mice. I. Pathogenicity of Mycoplasma pneumoniae, Mycoplasma salivarium, and Mycoplasma pulmonis for the lungs of conventional and gnotobiotic mice

Lutsky, Irving I. (Marquette University School of Medicine, Milwaukee, Wis.), and Avrum B. Organick. Pneumonia due to mycoplasma in gnotobiotic mice. I. Pathogenicity of Mycoplasma pneumoniae, Mycoplasma salivarium, and Mycoplasma pulmonis for the lungs of conventional and gnotobiotic mice. J. Bacteriol. 92:1154-1163. 1966.-Two species of mycoplasma of human origin, Mycoplasma pneumoniae and M. salivarium, were tested for their ability to produce respiratory disease in the Ha/ICR mouse when inoculated by the intranasal route. The mouse pathogen M. pulmonis was studied as a positive control. Conventional and gnotobiotic Ha/ICR mice were employed, the latter to provide a system free from indigenous mycoplasma and bacteria. Pneumonia from which mycoplasma were isolated was produced in all groups of the conventional Ha/ICR mice, including those inoculated with sterile broth. Only M. pulmonis produced disease when inoculated intranasally into the gnotobiotic mice, and the gross and microscopic lesions resembled those described in conventional mice. The gnotobiotic mouse provided a tool to study the pathogenicity of different mycoplasma species, and indicated marked differences in host specificity that could not be clearly seen when conventional mice were used.     

Cytokines in Mycoplasma pneumoniae infections

Mycoplasma pneumoniae (M. pneumoniae) is one of the smallest free-living bacteria known. Along with other unique characteristics of this genus, it lacks the typical peptidoglycan cell wall of most eubacteria. Best known for causing tracheobronchitis and atypical pneumonia in humans, this pathogen also causes a number of extrapulmonary syndromes such as meningitis/encephalitis and arthritis. Recent studies also suggest that infection may be associated with chronic conditions such as asthma. Although the mechanisms of M. pneumoniae pathogenesis remain to be elucidated, one important component of M. pneumoniae infections is the induction of proinflammatory and other cytokines in both acute and chronic conditions. In this review, we survey the induction of cytokines by M. pneumoniae in different model systems, and we discuss the possible role of induced cytokines in M. pneumoniae pathogenesis.     

Complete genome sequence of Mycoplasma pneumoniae type 2a strain 309, isolated in Japan

Mycoplasma pneumoniae strain 309, a type 2a (subtype 2 variant) strain of this bacterium, has variations in the P1 protein, which is responsible for attachment of the bacterium to host cells. Here, we report the complete genome sequence of M. pneumoniae strain 309 isolated from a pneumonia patient in Japan.     

Ultrastructural Features of Mycoplasma pneumoniae

The ultrastructure of Mycoplasma pneumoniae cultivated in broth on glass and plastic surfaces was studied by scanning and transmission electron microscopy. The organisms grew as filaments, which by over-crossing eventually formed a dense network on the surface and in colonies composed mainly of rounded and elongated forms. The filaments were usually thinner at the ends and terminated with a knob-like structure. Some filaments possessed short ramifications which also ended with a knob, and others showed constrictions. Sectioned organisms were seen to contain ribosome-like structures. Many organisms had a specialized structure at their thinner end, which consisted of a dense rod surrounded by electron-lucent cytoplasm and ending with a platelike thickening.     

Motility of Mycoplasma pneumoniae.

Cell of Mycoplasma pneumoniae FH gliding on a glass surface in liquid medium were examined by microscopic observation and quantitatively by microcinematography (30 frames per min). Comparisons were made only within the individual experiments. The cells moved in an irregular pattern with numerous narrow bends and circles. They never changed their leading end. The average speed (without pauses) was relatively constant between o.2 and 0.5 mum/s. The maximum speed was about 1.5 to 2.0 mum/s. The movements were interrupted by resting periods of different lengths and frequency. Temperature, viscosity, pH, and the presence of yeast extract in the medium influenced the motility significantly; changes in glucose, calcium ions, and serum content were less effective. The movements were affected by iodoacetate, p-mercuribenzoate, and mitomycin C at inhibitory or subinhibitory concentrations. Sodium fluoride, sodium cyanide, dinitrophenol, chloramphenicol, puromycin, cholchicin, and cytochalasin B at minimal inhibitory concentrations did not affect motility. The movements were effectively inhibited by anti-M. pneumoniae antiserum. Studies with absorbed antiserum suggested that the surface components involved in motility are heat labile. The gliding of M. pneumoniae cells required an intact energy metabolism and the proteins involved seemed to have a low turnover.