A low dose of Mycoplasma pneumoniae infection enhances an established allergic inflammation in mice: the role of the prostaglandin E2 pathway

Background Over 40% of chronic stable asthma patients have evidence of respiratory Mycoplasma pneumoniae (Mp) infection as detected by PCR, but not by serology and culture, suggesting that a low‐level Mp is involved in chronic asthma. However, the role of such a low‐level Mp infection in the regulation of allergic inflammation remains unknown. Objective To determine the impact of a low‐level Mp infection in mice with established airway allergic inflammation on allergic responses such as eosinophilia and chemokine eotaxin‐2, and the underlying mechanisms [i.e. the prostaglandin E₂ (PGE₂) pathway] since PGE₂ inhalation before an allergen challenge suppressed the eosinophil infiltration in human airways. Methods BALB/c mouse models of ovalbumin (OVA)‐induced allergic asthma with an ensuing low‐ or high‐dose Mp were used to assess IL‐4 expression, bronchoalveolar lavage (BAL) eosinophil, eotaxin‐2 and PGE₂ levels, and lung mRNA levels of microsomal prostaglandin E synthase‐1 (mPGES‐1). Primary alveolar macrophages (pAMs) from naïve BALB/c mice were cultured to determine whether Mp‐induced PGE₂ or exogenous PGE₂ down‐regulates IL‐4/IL‐13‐induced eotaxin‐2. Results Low‐dose Mp in allergic mice significantly enhanced IL‐4 and eotaxin‐2, and moderately promoted lung eosinophilia, whereas high‐dose Mp significantly reduced lung eosinophilia and tended to decrease IL‐4 and eotaxin‐2. Moreover, in both OVA‐naïve and allergic mice, lung mPGES‐1 mRNA and BAL PGE₂ levels were elevated in mice infected with high‐dose, but not low‐dose Mp. In pAMs, IL‐4/IL‐13 significantly increased eotaxin‐2, which was reduced by Mp infection accompanied by dose‐dependent PGE₂ induction. Exogenous PGE₂ inhibited IL‐4/IL‐13‐induced eotaxin‐2 in a dose‐dependent manner. Conclusions This study highlights a novel concept on how different bacterial loads in the lung modify the established allergic airway inflammation and thus interact with an allergen to further induce Th2 responses. That is, unlike high‐level Mp, low‐level Mp fails to effectively induce PGE₂ to down‐regulate allergic responses (e.g. eotaxin‐2), thus maintaining or even worsening allergic inflammation in asthmatic airways.     

支原体抗体检测对诊断小儿呼吸道感染的临床意义研究

目的:探讨支原体抗体检测对诊断小儿呼吸道感染的临床意义。方法:选取于本院诊治的呼吸道感染小儿185例作为观察组,同期185例健康小儿为作对照组,然后将两组支原体抗体检测阳性率进行统计及比较,另将观察组中不同年龄段及性别的阳性率进行比较。结果:观察组的不同稀释倍数的支原体抗体检测阳性率均高于对照组,而观察组中3～7岁患儿的阳性率最高,高于其他年龄段,差异有统计学意义(P<0.05),而不同性别者之间的检出率则无明显差异,差异无统计学意义(P>0.05)。结论:支原体抗体检测对诊断小儿呼吸道感染的临床意义较高,对于小儿患者的疾病诊断价值较高。     

327例输卵管性不孕患者生殖道衣原体、支原体检测及药物敏感分析

目的 探讨输卵管性不孕症患者生殖道衣原体和支原体感染的状况及药物敏感性,指导临床合理用药.方法 随机选取327例输卵管性不孕症患者作为不孕组和286名健康孕妇作为对照组,采集宫颈分泌物,检测沙眼衣原体(CT)、解脲支原体(UU)和人型支原体(MH),以及UU和MH耐药性.结果 不孕组CT感染率(14.99%)、UU感染率(23.24%)、UU+MH感染率(29.05%)、CT+UU+MH感染率(9.17%)及总感染率(88.99%)均高于对照组(依次为:2.80%、6.99%、8.39%、4.55%、29.02%),两组比较,差异有统计学意义(P＜0.05);UU对罗红霉素(敏感性为96.05%)、交沙霉素(敏感性为96.05%)、四环素(敏感性为82.89%)强力霉素(敏感性为92.11%)、克拉霉素(敏感性为96.05%)敏感率较高,对环丙沙星和乙酰螺旋霉素相对耐药;MH对交沙霉素(敏感性为95.83%)、强力霉素(敏感性为91.67%)、美满霉素(敏感性为83.33%)、壮观霉素(敏感性为75.00%)较敏感,对红霉素、罗红霉素、阿奇霉素、克拉霉素不敏感,耐药性较高;UU+MH仅仅对交沙霉素(敏感性为90.52%)较敏感,对红霉素、罗红霉素、乙酰螺旋霉素、环丙沙星、氧氟沙星、阿奇霉素、克拉霉素的耐药性极高(77.89%-91.58%).结论 CT、UU、MH感染与输卵管性不孕有一定相关性,输卵管性不孕患者CT、UU和MH感染率较高于能生育者;UU和MH及UU+MH对多种常见抗菌药物具有较强的耐药性,临床治疗应重视病原学检测,合理使用抗生素.

Abstract：

Objective To explore the effects of mycoplasma and chlamydia infections on tubal infertilityand to assess the antibiotic susceptibility and resistance of female urogenital, and consequently to guide clinical rational drug use. Methods 327 tubal infertility women as infertility group and 286 healthy pregnant women as control group were randomly selected, detected chlamydia trachomatis ( CT) , ureaplasma urealyticum ( UU) and mycoplasma hominis ( MH) in cervical secretions and drug resistance of UU and MH. Results CT infection rates ( 14. 99% ), UU infection rates (23. 24% ) , UU + MH infection rates (29.05% ) ,CT + UU + MH infection rates(9. 17% )and total infection rates(88.99% )in infertility group is higher than those (order: 2. 80% ,6. 99% , 8. 39% ,4. 55% ,29.02% ) in the control group, comparisons of two groups are statistically significant differences (P ＜ 0.05 ), the susceptibility of UU to roxithromycin (sensitivity is 96. 05% ), josamycin ( sensitivity is 96.05% ), tetracycline ( sensitivity is 82.89%), vibramycin( sensitivity is 92. 11% ) and clarithromycin( sensitivity is 96.05% ) were relatively high and low to ciprofloxacin and acetyl spiramycin. The susceptibility of MH to josamycin ( sensitivity is 95. 83% ) , vibramycin ( sensitivity is 91. 67% ), minocin ( sensitivity is 83.33%) and actinospectacin ( sensitivity is 75. 00% ) were relatively high and low to erythromycin, azithromycin, roxithromycin and clarithromycin. UU + MH was only sensitive to josamycin ( sensitivity is 90. 52% ), high resistance ( 77. 89% -91. 58% ) to erythromycin, azithromycin, acetyl spiramycin, ciprofloxacin, ofloxacin, azithromycin and clarithromycin.Conclusion Infection of CT, UU, MH and tubal infertility have certain relevance, the rates of CT, UU and MH infection in tubal infertility patients higher than fertile people. For many commonantibacterial drugs, UU, MH and UU + MH has strong resistance, the etiology detection and using adapted antibios should be taken seriously in clinical treatment.     

Prevalence of Mycoplasma IgM in children with lower respiratory tract illness

Background:  Few data are available for the recent occurrence of Mycoplasma infections in children in Japan. The purpose of the present study was therefore to identify the prevalence of Mycoplasma infections in children in Japan.
Methods:  IgM antibodies to M. pneumoniae were prospectively determined using the Meridian ImmunoCard Mycoplasma test in hospitalized patients with lower respiratory tract infections between January 2004 and June 2007. A total of 858 hospitalized patients aged 0–15 years (445 male, 413 female), diagnosed as having acute pneumonia or bronchitis, were enrolled. The number of patients with pneumonia or bronchitis was 331 (male/female, 167/164) and 527 (male/female/ 278/249), respectively. Two hundred and five of the 858 patients (23.9%) were ImmunoCard positive. Of the 205 patients, 121 children and 84 children were diagnosed as having pneumonia and bronchitis, respectively. One hundred and forty-three of the 727 patients (19.7%) <5 years of age were ImmunoCard test positive.
Conclusions:  M. pneumoniae infection is not rare in children aged <5 years in Japan.     

Effects of Mycoplasma pneumoniae infection on sphingolipid metabolism in human lung carcinoma A549 cells

The role of sphingolipids in bacterial pathogenesis has been gradually recognized. In an effort to identify the possible involvement of sphingolipids during Mycoplasma pneumoniae (M. pneumoniae) infection, we first adopted a lipidomic approach to achieve the profiles of major sphingolipid species of M. pneumoniae as well as human lung carcinoma A549 cells, and further evaluated the effects of M. pneumoniae infection on sphingolipid metabolism in A549 cells. It was shown that M. pneumoniae and A549 cells share many common sphingolipid species, however, M. pneumoniae possesses certain specific molecular species that are not found in A549 cells. On the other hand, M. pneumoniae infection could alter sphingolipid metabolism in A549 cell, including the generation of new ceramide and sphingomyelin species, or the increase/decrease of intensities, which varies depending on the different infection doses and times. The effects of M. pneumoniae infection on two key enzymes in sphingolipid metabolism, serine palmitoyltransferase (SPT) and acid sphingomyelinase (ASM), were also examined. It was found that M. pneumoniae infection could affect the expression of SPT or the distribution of ASM at certain concentrations. These data suggest that M. pneumoniae infection could influence sphingolipid metabolism of its host, which might be related to its pathogenicity.     

Pathogenesis of Mycoplasma pneumoniae: An update

Genus Mycoplasma, belonging to the class Mollicutes, encompasses unique lifeforms comprising of a small genome of 8,00,000 base pairs and the inability to produce a cell wall under any circumstances. Mycoplasma pneumoniae is the most common pathogenic species infecting humans. It is an atypical respiratory bacteria causing community acquired pneumonia (CAP) in children and adults of all ages. Although atypical pneumonia caused by M. pneumoniae can be managed in outpatient settings, complications affecting multiple organ systems can lead to hospitalization in vulnerable population. M. pneumoniae infection has also been associated with chronic lung disease and bronchial asthma. With the advent of molecular methods of diagnosis and genetic, immunological and ultrastructural assays that study infectious disease pathogenesis at subcellular level, newer virulence factors of M. pneumoniae have been recognized by researchers. Structure of the attachment organelle of the organism, that mediates the crucial initial step of cytadherence to respiratory tract epithelium through complex interaction between different adhesins and accessory adhesion proteins, has been decoded. Several subsequent virulence mechanisms like intracellular localization, direct cytotoxicity and activation of the inflammatory cascade through toll-like receptors (TLRs) leading to inflammatory cytokine mediated tissue injury, have also been demonstrated to play an essential role in pathogenesis. The most significant update in the knowledge of pathogenesis has been the discovery of Community-Acquired Respiratory Distress Syndrome toxin (CARDS toxin) of M. pneumoniae and its ability of adenosine diphosphate (ADP) ribosylation and inflammosome activation, thus initiating airway inflammation. Advances have also been made in terms of the different pathways behind the genesis of extrapulmonary complications. This article aims to comprehensively review the recent advances in the knowledge of pathogenesis of this organism, that had remained elusive during the era of serological diagnosis. Elucidation of virulence mechanisms of M. pneumoniae will help researchers to design effective vaccine candidates and newer therapeutic targets against this agent.     

小儿支原体肺炎70例临床分析

目的 探讨小儿支原体肺炎的临床特点和实验室诊断，为治疗提供依据。方法 用聚合酶链反应(PCR)法检测咽拭子标本中MP—DNA。结果 265名咳嗽患儿咽拭子标本进行支原体(MP)感染的检查，发现MP阳性70例，阳性率26％。结论 小儿支原体肺炎临床表现缺少特异性，PCR检查是一种有早期诊断价值的检查方法，治疗上首选红霉素或罗红霉素。     

小儿支原体肺炎免疫状况与肺部影像学改变的预后分析

目的：探讨肺炎支原体肺炎（MPP）患儿免疫功能状况、肺部影像学改变及其顶后的关系，为早期判断病情的严重程度及有效治疗提供依据。方法：回顾性分析89例确诊为MPP患儿的临床资料，按热程、肺部体征及肺外并发症将其分为轻症组和重症组，比较两组间血清免疫球蛋白变化、外周血白细胞及中性粒细胞计数、肺部影像学资料及平均住院天数、住院费用。结果：轻症组患儿入院后1周血清IgG、IgA、IgM升高值显著高于重症组（P〈0.01～0.05），重症组入院时胸片评分显著高于轻症组（P〈0.01），两组入院时自细胞总数及中性粒细胞计数差异均无显著性（P〉0.05），轻症组的平均住院天数及平均住院费用均显著低于重症组（P〈0.01）。结论：患儿体液免疫水平与MPP的发展和预后密切相关。测定血清免疫球蛋白及对胸片评分对于判断MPP患儿的病情程度、预后和指导临床治疗具有一定的意义。     

女性生殖道支原体检测及体外抗菌活性分析

目的:了解女性生殖道支原体感染及对常用抗菌药物的药敏情况。方法:采用支原体试剂盒进行支原体培养、鉴定及药敏试验。结果:355份被检标本中检出支原体阳性233份,总检出率为65．6％。其中,解脲脲原体(Uu)感染占88．0％,人型支原体(Mh)感染占1．3％,Uu和Mh混合感染占10．7％。10种抗菌药物对支原体的敏感性由高到低依次为:交沙霉素(96．0％)、多西环素(91．1％)、美满霉素(89．6％)、克拉霉素(80．7％)、司帕沙星(75．2％)、罗红霉素(60．4％)、阿奇霉素(45．0％)、氧氟沙星(42．1％)、环丙沙星(28．2％)、大观霉素(11．4％)。结论:女性生殖道支原体感染以Uu感染为主,Uu和Mh混合感染耐药率高。有实验条件的医疗机构,治疗支原体感染应参考药敏试验结果。     

泌尿生殖道支原体感染检测及耐药性分析

[目的]了解泌尿生殖道支原体感染的现状及耐药性,为临床医生合理选择抗生素提供依据。[方法]采用支原体培养及药敏试剂盒,对生殖道炎症患者分泌物进行支原体检测,同时测定其药敏试验。[结果]304例患者中137例支原体阳性,阳性率为45.07%;其中解脲支原体(Uu)感染135例,阳性率为44.41%,Uu与人支原体(Mh)混合感染22例,混合感染率为7.24%。女性感染率明显高于男性,Mh的耐药率明显高于Uu,Uu耐药率最高的是氧氟沙星,耐药率最低的是强力霉素和美满霉素;MH耐药率最高的是罗红霉素和氧氟沙星,耐药率最低的是强力霉素和美满霉素。[结论]泌尿生殖道感染主要以Uu发病率最高,且耐药菌株在不断增加,应根据药敏结果合理使用抗生素。