The incidence of Chlamydia pneumoniae lower respiratory tract infections among university students in northern California.

Chlamydia pneumoniae has recently been identified as a cause of lower respiratory tract infections. From March 1987 to March 1988, 259 university students-151 students with lower respiratory tract infections and 108 controls-from the University of California, Berkeley, were studied to determine the incidence and pattern of C pneumoniae lower respiratory tract infections. Serologic evidence of a recent C pneumoniae infection was found in less than 2%, and the organism was not isolated from any of the subjects. Despite the paucity of evidence of a recent infection, 47.5% of this university population showed serologic evidence of a previous C pneumoniae infection. The lower incidence of C pneumoniae infection in our population, when compared with previous reports, suggests that there may be geographic and temporal differences or fluctuations among populations.     

产超广谱β-内酰胺酶肺炎克雷伯菌血流感染的耐药性、危险因素及临床结局分析

本研究旨在分析107例肺炎克雷伯菌血流感染患者的临床资料,探讨产超广谱β-内酰胺酶(extended-spectrumβ-lactamase,ESBL)肺炎克雷伯菌血流感染的耐药特点、危险因素及临床结局,为防治产ESBL肺炎克雷伯菌血流感染提供临床理论参考。选取2012年1月—2016年6月于深圳市南山区人民医院住院且血培养肺炎克雷伯菌阳性的107例患者,根据药敏结果分成产ESBL血流感染组(20例)和非产ESBL血流感染组(87例)。107例患者血流感染主要继发于肺部感染(38.32%)及泌尿系感染(14.02%),细菌对碳青霉烯类抗生素敏感性好。单因素及logistic回归分析结果显示,医院内感染和入院前有外伤史为产ESBL肺炎克雷伯菌血流感染的危险因素。总体肺炎克雷伯菌血流感染病死率为17.76%,产ESBL组与非产ESBL组之间病死率无显著性差异(25%vs.16.09%)。结果提示,产ESBL不是预测肺炎克雷伯菌血流感染患者死亡的独立危险因素。     

Identification of vaccine candidate antigens of an ESBL producing Klebsiella pneumoniae clinical strain by immunoproteome analysis

Klebsiella pneumoniae is an opportunistic pathogen which causes pneumoniae, urinary tract infections and septicemia in immunocompromised patients. Hospital outbreaks of multidrug-resistant K. pneumoniae, especially those in neonatal wards, are often caused by strains producing the extended-spectrum-beta-lactamases (ESBLs). An immunoproteome based approach was developed to identify candidate antigens of K. pneumoniae for vaccine development. Sera from patients with acute K. pneumoniae infections (n = 55) and a control group of sera from healthy individuals (n = 15) were analyzed for reactivity by Western blot against ESBL K. pneumoniae outer membrane proteins separated by 2-DE. Twenty highly immunogenic protein spots were identified by immunoproteomic analysis. The immunogenic proteins that are most frequently recognized by positive K. pneumoniae sera were OmpA, OmpK36, FepA, OmpK17, OmpW, Colicin I receptor protein and three novel proteins. Two of the vaccine candidate genes, OmpA (Struve et al. Microbiology 2003, 149, 167-176) and FepA (Lai, Y. C. et al.. Infect Immun 2001, 69, 7140-7145), have recently been shown to be essential in colonization and infection in an in vivo mouse model. Hence, these two immunogenic proteins could serve as potential vaccine candidates.     

Chlamydia pneumoniae infection results in generalized bone loss in mice

Osteoporosis is associated with a general bone loss. Whether infections could contribute to osteoporosis is not known. Chlamydia pneumoniae causes chronic infections and produces potentially bone resorptive cytokines. The effect of C. pneumoniae infection was investigated in vivo in 10-week old mice (c57BL/6) and in vitro in the human osteoblast-like cell line hFOB 1.19 (hFOB). Bone mineral density (BMD) was measured before and 16 days after infection. C. pneumoniae-infected mice had decreased (p<0.05) total and subcortical BMD at the distal femur and proximal tibia compared with controls, but no body-weight gain differences. IL-6 (56 vs. 39pg/mL, p=0.02) and IL-1beta (11 vs. 0pg/mL, p=0.003) levels in sera, and CD3(+) T-cells (p=0.04) were higher in infected mice compared with controls. In vitro, hFOB infected with C. pneumoniae was associated with increased IL-6 (p=0.01) and RANKL (p<0.05) mRNA expression; additionally, IL-6 secretion increased in a dose-dependent manner (p<0.05). In summary, mice infected with C. pneumoniae had generalized bone loss associated with increased IL-6 and IL-1. In addition, C. pneumoniae established an infection in an osteoblast cell line in vitro with similar cytokine profiles as those in vivo, supporting a causal linkage.     

Prevalence of Mycoplasma pneumoniae and Chlamydia pneumoniae in pneumonia patients in four major hospitals in Trinidad

The prevalence of current Mycoplasma pneumoniae and Chlamydia pneumoniae infections in patients with pneumonia in Trinidad, and the relationship between pneumonia and risk factors were investigated. Blood samples were collected from 132 patients diagnosed by attending physicians, as suffering from pneumonia at four hospitals in Trinidad. Serum samples were tested for M. pneumoniae IgM and IgG and C. pneumoniae IgM by the enzyme immunoassay (EIA). In addition, C. pneumoniae IgM and IgG were detected using microimmunofluorescence (MIF). A comprehensive questionnaire which addressed demographic information as well as risk factors for pneumonia was administered to patients. All analyses were done using the Statistical Package for Social Sciences (SPSS), version 9. Seroprevalences of 46.0% (58 of 126) were found for C. pneumoniae Ig M/G, and 66.7% (88 of 132) for M. pneumoniae Ig M/G. The difference was statistically significant (p < 0.01; chi2). Thirty-four percent (43 of 125) for C. pneumoniae Ig M/acute Ig G and 28.8% (36 of 125) of M. pneumoniae IgM were not statistically significant (p > 0.05; chi2). Hospital, gender and ethnicity of patients did not significantly (p > 0.05; chi2) affect the seroprevalence of the bacteria assayed for. However, the prevalence of C. pneumoniae (23.3%) in patients under 21 years old compared to other age groups was statistically significant (p = 0.043; chi2). Overall, the seroprevalence to both pathogens was not significantly (p > 0.05; chi2) affected by comorbidities and signs/symptoms. It was concluded that new infections by C. pneumoniae in pneumonia patients may be an important aetiological agent for the condition in Trinidad.     

Serological study on Chlamydophila pneumoniae in patients with community-acquired pneumonia

This study aimed to evaluate the incidence of Chlamydophila pneumoniae antibodies in patients with community acquired pneumonia (CAP) by a new ELISA test (EIA CP-IgG, IgA, IgM--Eurospital, Trieste, Italy). From January 1999 to July 2001 141 patients with clinical signs of CAP were enrolled in sixteen Italian Hospitals. Specific IgM and IgG antibodies anti-C. pneumoniae in serum and IgA in both serum and sputum were detected. At a primary inspection (time T-0) serum and sputum samples were taken from 115/141 patients, whereas serum was collected from only 100/141 patients after 30 days (time T-30). At T-0 24/115 (20.8%) patients showed serological markers thus suggesting an acute C. pneumoniae infection. In 23/24 patients the overall serological pattern found at T-0 was confirmed at T-30. In 32/115 patients (27.8%) serological markers of C. pneumoniae past infection were found positive and were confirmed 30 days later. These data support the role of C. pneumoniae as an important aetiological agent of CAP throughout different geographic areas of Italy. The test was suitable for the laboratory diagnosis of C. pneumoniae infection. In particular, the presence of specific IgA anti- C. pneumoniae in both serum and sputum proved useful to define different stages and evolution of infection.     

Anti-smooth muscle antibody in clinical human and experimental animal Mycoplasma pneumoniae infection

Autoantibody formation is possibly integral to the development of non-respiratory manifestations of acute Mycoplasma pneumoniae infection. We sought to confirm the occurrence of smooth muscle antibodies (SMA) in humans with acute Myc. pneumoniae respiratory infection and furthermore to assess whether similar autoantibodies would develop in a hamster model of respiratory infection. Paired sera from 21 patients with acute infection were assayed for SMA by immunofluorescence on mouse kidney/stomach substrates. The frequency of SMA was then determined for 52 paediatric patients with acute Myc. pneumoniae infection and 16 controls, and for sera from a hamster model of infection. Five of 21 paired sera had an increment in SMA between acute and convalescent specimens. At a screening dilution of 1:40, 18/52 infected and 0/16 controls had positive sera ( P = 0.003); positive specimens demonstrated IgG rather than IgM SMA. In the hamster model of Myc. pneumoniae respiratory infection, significant IgG SMA increases occurred in 7/19 infections but not in 11 controls ( P = 0.02). Immunoblotting did not identify actin as the substrate for SMA. Smooth muscle antibody increases are found in a significant minority of Myc. pneumoniae -infected humans and hamsters. A role for SMA in the pathogenesis of Myc. pneumoniae infection remains to be defined.     

Chlamydia pneumoniae and atherosclerosis

Exposure to Chlamydia pneumoniae is extremely common, and respiratory infections occur repeatedly among most people. Strong associations exist between C. pneumoniae infection and atherosclerosis as demonstrated by: (i) sero-epidemiological studies showing that patients with cardiovascular disease have higher titres of anti-C. pneumoniae antibodies compared with control patients; (ii) detection of the organism within atherosclerotic lesions, but not in adjacent normal tissue by immunohistochemistry, polymerase chain reaction and electron microscopy and by culturing the organism from lesions; and (iii) showing that C. pneumoniae can either initiate lesion development or cause exacerbation of lesions in rabbit and mouse animal models respectively. The association of this organism with atherosclerosis has also provided sufficient impetus to conduct a variety of human secondary prevention antibiotic treatment trials. The results of these studies have been mixed and, thus far, no clear long-lasting benefit has emerged from these types of investigations. Studies of C. pneumoniae pathogenesis have shown that the organism can infect many cell types associated with both respiratory and cardiovascular sites, including lung epithelium and resident alveolar macrophages, circulating monocytes, arterial smooth muscle cells and vascular endothelium. Infected cells have been shown to exhibit characteristics associated with the development of cardiovascular disease (e.g. secretion of proinflammatory cytokines and procoagulants by infected endothelial cells and foam cell formation by infected macrophages). More detailed analysis of C. pneumoniae pathogenesis has been aided by the availability of genomic sequence information. Genomic and proteomic analyses of C. pneumoniae infections in relevant cell types will help to define the pathogenic potential of the organism in both respiratory and cardiovascular disease.     

Repeated respiratory Mycoplasma pneumoniae infections in mice: effect of host genetic background

Respiratory Mycoplasma pneumoniae (Mp) infection is involved in several acute and chronic lung diseases including community-acquired pneumonia, asthma and chronic obstructive pulmonary disease. In the chronic disease process, recurrent respiratory bacterial infections could occur, which may result in varying degrees of symptoms and lung inflammation among patients. However, the lung immunologic differences of host responses to repeated bacterial (i.e., Mp) infections remain to be determined. In the present study, we examined cellular and humoral responses to multiple (up to 3) Mp infections in two genetically different strains of mice (BALB/c and C57BL/6). Mice were intranasally inoculated with one Mp infection, two or three Mp infections (4 weeks apart), and sacrificed on days 3, 7 and 14 after the last Mp infection. Overall, compared to C57BL/6 mice, BALB/c mice demonstrated a significantly higher degree of lung tissue inflammatory cell infiltrate, BAL cellularity, and release of pro-inflammatory cytokines (TNF-alpha, keratinocyte-derived chemokine (KC, a mouse homolog of human chemokine Gro-alpha [CXCL1], and IFN-gamma). In addition, BALB/c mice presented higher levels of serum Mp-specific IgG and IgM, but not IgA. Consistently with lung and serum data, Mp load in BAL and lung specimens was significantly higher in BALB/c mice than C57BL/6 mice. Moreover, repeated Mp infections in BALB/c, but not C57BL/6 mice, produced a greater inflammatory response than did a single Mp infection. Our results suggest that hosts with different genetic background may have different susceptibility to repeated respiratory Mp infections along with inflammatory responses.     

High prevalence of Mycoplasma infections among European chronic fatigue syndrome patients. Examination of four Mycoplasma species in blood of chronic fatigue syndrome patients

Prevalence of Mycoplasma species infections in chronic fatigue syndrome (CFS) has been extensively reported in the scientific literature. However, all previous reports highlighted the presence of Mycoplasmas in American patients. In this prospective study, the presence of Mycoplasma fermentans, M. penetrans, M. pneumoniae and M. hominis in the blood of 261 European CFS patients and 36 healthy volunteers was examined using forensic polymerase chain reaction. One hundred and seventy-nine (68.6%) patients were infected by at least one species of Mycoplasma, compared to two out of 36 (5.6%) in the control sample (P<0.001). Among Mycoplasma-infected patients, M. hominis was the most frequently observed infection (n=96; 36.8% of the overall sample), followed by M. pneumoniae and M. fermentans infections (equal frequencies; n=67; 25.7%). M. penetrans infections were not found. Multiple mycoplasmal infections were detected in 45 patients (17.2%). Compared to American CFS patients (M. pneumoniae>M. hominis>M. penetrans), a slightly different pattern of mycoplasmal infections was found in European CFS patients (M. hominis>M. pneumoniae, M. fermentansz.Gt;M. penetrans).     

Severe asthma exacerbation: role of acute Chlamydophila pneumoniae and Mycoplasma pneumoniae infection

Background

Chlamydophila pneumoniae and Mycoplasma pneumoniae are associated with acute exacerbation of bronchial asthma (AEBA). The aim of this study was to evaluate the correlation between these acute bacterial infections and the severity of AEBA.

Methods

We prospectively analysed consecutive patients admitted to the Emergency Department with acute asthma exacerbation. In every patient peak expiratory flow (PEF) measurement was performed on admission, and spirometry during follow-up. Serology for Chlamydophila and Mycoplasma pneumoniae was performed on admission and after 4–8 weeks.

Results

Fifty-eight patients completed the study. Acute atypical infections (AAI) was observed in 22/58 cases; we found single acute C. pneumoniae in 19 cases, single acute M. pneumoniae in 2 cases, and double acute infection in one case. Functional impairment on admission was greater in patients with AAI than in patients without AAI (PEF 205 ± 104 L/min vs 276 ± 117 p = 0.02) and persisted until visit 2 (FEV1% 76.30 ± 24.54 vs FEV1% 92.91 ± 13.89, p = 0.002). Moreover, the proportion of patients who presented with severe AEBA was significantly greater in the group with AAI than in the group without AAI (15/22 vs 12/36, p = 0.01; OR 4.29, 95% CI 1.38–13.32).

Conclusion

Our data suggest an association between acute atypical infection and a more severe AEBA.     

Specificity of the microimmunofluorescence assay for the serodiagnosis of Chlamydia pneumoniae infections.

Chlamydia pneumoniae infections are mostly confirmed using an indirect microimmunofluorescence test for which potential cross-reactions between antigens from different chlamydial species are not well documented. Using this assay, 928 sera (507 subjects) submitted for Chlamydia pneumoniae serology were tested for specific IgM and IgG to this bacteria using the TW-183 antigen. IgM and IgG reactivities to Chlamydia trachomatis serotypes C, D, E, and L2 and Chlamydia psittaci strain 6BC antigens were also tested. A sample was interpreted as positive only when evenly fluorescent elementary bodies were observed. Twenty-five subjects (4.9%) showed serological evidence of recent Chlamydia pneumoniae infection (IgM positive and (or) IgG seroconversion); 11 of them also showed serological evidence of recent infection with at least one other chlamydial species. Specificity was 50 and 63% for IgM and IgG detection, respectively. These results suggest that mixed or temporally related infections might occur, or, more likely, that some Chlamydia pneumoniae IgM or IgG reactivities might be due to heterotypic antibodies.     

Distinct NKT cell subsets are induced by different Chlamydia species leading to differential adaptive immunity and host resistance to the infections

We investigated the role of NKT cells in immunity to Chlamydia pneumoniae and Chlamydia muridarum infections using a combination of knockout mice and specific cellular activation approaches. The NKT-deficient mice showed exacerbated susceptibility to C. pneumoniae infection, but more resistance to C. muridarum infection. Activation of NKT reduced C. pneumoniae in vivo growth, but enhanced C. muridarum infection. Cellular analysis of invariant NKT cells revealed distinct cytokine patterns following C. pneumoniae and C. muridarum infections, i.e., predominant IFN-gamma in the former, while predominant IL-4 in the latter. The cytokine patterns of CD4(+) and CD8(+) T cells matched those of NKT cells. Our data provide in vivo evidence for a functionally diverse role of NKT cells in immune response to two intracellular bacterial pathogens. These results suggest that distinct NKT subsets are induced by even biologically closely related pathogens, thus leading to differential adaptive immune response and infection outcomes.     

A preliminary evaluation of a new enzyme immunoassay to detect Chlamydia pneumoniae-specific antibodies

New enzyme immunoassays (EIAs) for determination of specific IgG, IgA, and IgM antibody titers to Chlamydia pneumoniae were evaluated independently in three research laboratories. Specificity of the EIAs was enhanced by removing LPS from the chlamydial antigen. The performance of these EIAs was evaluated in comparison with the microimmunofluorescence (MIF) test using specimens from: (i) a group of adult patients with community-acquired pneumonia (CAP) previously diagnosed as having an acute chlamydial infection by the complement fixation test or the whole inclusion fluorescence test; (ii) from a group of adult patients with acute respiratory tract infections; and (iii) from a group of young children consecutively presenting with acute respiratory tract infections. The MIF test and the EIAs detected acute infections in paired serum specimens from 12 of 14 patients from the first group. Eleven of these 12 patients were positive in both tests. The MIF test detected seven acute infections in single convalescence serum specimens from eight patients. Two of these were also positive in the EIAs. Paired serum specimens from the second group of adult patients (n=12) were collected during an epidemic of C. pneumoniae. The EIAs detected six acute infections. The MIF test detected two additional patients with acute infections. From the group of young children (n=30), the EIAs detected two patients with acute infections. Our conclusion from this preliminary evaluation is that these EIAs could be useful for laboratory diagnosis of acute C. pneumoniae infections. Comprehensive prospective studies should provide suitable data to calculate the sensitivity, specificity, and predictive values.     

石家庄地区肺炎支原体感染的流行病学调查

目的：了解石家庄地区肺炎支原体感染的血清流行病学情况。方法：选择2011年3月-2012年2月我院住院和门诊收治的急性呼吸道感染患者1902例为研究对象,采用间接免疫荧光法（IFA）检测其血清肺炎支原体IgM抗体,并分析其流行病学资料。结果：1902例血清标本中,284例（14．93％）肺炎支原体IgM抗体阳性,男性和女性的阳性率无显著差异。肺炎支原体抗体阳性的患者主要分布于0～15岁年龄段,阳性检出率最高的年龄组为0～6岁,占21．26％（132／621）。各个季节均有肺炎支原体感染阳性患者,感染率无显著差异性,秋（80例）、冬（96例）两季的阳性感染率高于春（56例）、夏（52例）两季。患者100％出现发热症状,95．77％出现咳嗽。结论：石家庄地区肺炎支原体感染的主要人群为未成年人,无季节性和性别差异,以发热和咳嗽为最主要的临床症状。     

Detection of serum antibodies against Chlamydia pneumoniae by ELISA

Abstract Chlamydia pneumoniae causes pneumonia and other respiratory infections in children, adolescents and adults. We tried to evaluate the diagnostic value of detection of serum antibodies by ELISA for C. pneumoniae infections in Japanese children. Serum IgG, IgA and IgM antibodies to C. pneumoniae were determined by the microimmunofluorescence (MIF) test. Serum IgG and IgA antibodies were also determined by ELISA test kits. Results obtained by ELISA were compared with those obtained by MIF test. IgG antibody to C. pneumoniae was detected in 135 (39.5%) by ELISA and in 125 (36.5%) by MIF out of 342 sera from Japanese infants and children without respiratory infections (aged from 2 months old to 15 years old). IgA antibody to C. pneumoniae was detected in 129 (37.7%) by ELISA and in 117 (34.2%) by MIF out of 342 sera tested. Of 342 specimens 113 were IgG-positive by ELISA and MIF (sensitivity: 90.4%, specificity: 89.9%, r = 0.853). Of 342 sera 28 had IgG antibody titers of 1:256 and none had titers 1:512 or higher by MIF. Of 28 infants and children a total of nine were less than 4 years of age. On the other hand, of 342 specimens 99 were IgA-positive by ELISA and MIF (sensitivity: 84.6%, specificity: 86.7%, r = 0.769). Of 342 sera 16 had IgA antibody titers of 1:256 or higher by MIF. Of 16 infants and children, ten were less than 4 years of age. ELISA had excellent sensitivity and specificity relative to MIF test for detection of IgC and IgA antibodies to C. pneumoniae . It was suggested that C. pneumoniae infection in Japanese infants and children under 4 years of age was not infrequent.     

Genomic screening for Chlamydophila pneumoniae-specific antigens using serum samples from patients with primary infection

Chlamydophila pneumoniae, an obligate intracellular human pathogen, causes respiratory tract infections. The most common techniques used for the serological diagnosis of C.?pneumoniae infections are microimmunofluorescence tests and commercial serological ELISA tests; these are based on the detection of antibodies against whole chlamydial elementary bodies and lipopolysaccharide/outer membrane protein, respectively. Identification of more specific and highly immunodominant antigens is essential for the development of new serodiagnostic assays. To identify novel specific antigens from C.?pneumoniae, we screened 455 genes with unknown function in the genome of C.?pneumoniae J138. Extracts of Saccharomyces cerevisiae cells expressing GFP-tagged C.?pneumoniae proteins were subjected to Western blot analysis using serum samples from C.?pneumoniae-infected patients as the primary antibodies. From this comprehensive analysis, 58 clones expressing C.?pneumoniae open reading frames, including hypothetical proteins, were identified as antigens. These results have provided useful information for the development of new serological tools for the diagnosis for C.?pneumoniae infections and for the development of vaccines in future.     

高毒力肺炎克雷伯菌致病及耐药分子机制研究进展

近年来,肺炎克雷伯菌已成为医院内感染及社区获得性感染的常见致病菌,临床标本分离率仅次于大肠埃希菌.根据毒力特征差异,肺炎克雷伯菌可分为经典肺炎克雷伯菌和高毒力肺炎克雷伯菌2种类型.高毒力肺炎克雷伯菌是引起化脓性肝脓肿的主要病原菌,其感染可出现内源性转移,包括眼、肺和中枢神经系统;此外还与原发性肝外感染有关,包括菌血症、...     

Chlamydia pneumoniae inhibits activated human T lymphocyte proliferation by the induction of apoptotic and pyroptotic pathways

Chlamydia pneumoniae is an omnipresent obligate intracellular bacterial pathogen that infects numerous host species. C. pneumoniae infections of humans are a common cause of community acquired pneumonia but have also been linked to chronic diseases such as atherosclerosis, Alzheimer's disease, and asthma. Persistent infection and immune avoidance are believed to play important roles in the pathophysiology of C. pneumoniae disease. We found that C. pneumoniae organisms inhibited activated but not nonactivated human T cell proliferation. Inhibition of proliferation was pathogen specific, heat sensitive, and multiplicity of infection dependent and required chlamydial entry but not de novo protein synthesis. Activated CD4(+) and CD8(+) T cells were equally sensitive to C. pneumoniae antiproliferative effectors. The C. pneumoniae antiproliferative effect was linked to T cell death associated with caspase 1, 8, 9, and IL-1β production, indicating that both apoptotic and pyroptotic cellular death pathways were activated after pathogen-T cell interactions. Collectively, these findings are consistent with the conclusion that C. pneumoniae could induce a local T cell immunosuppression and inflammatory response revealing a possible host-pathogen scenario that would support both persistence and inflammation.