Chlamydophila pneumoniae infection and COPD: more evidence for lack of evidence?

The relationship between glycated hemoglobin A1c levels and exacerbation status in the patients with chronic obstructive pulmonary disease

OBJECTIVE

This study was performed in Razi Hospital, Rasht, Iran, between March 2016 and August 2018 on a population of chronic obstructive pulmonary disease (COPD) patients (56 as COPD exacerbation group and 56 as COPD stable group). Study variables include age, sex, occupation, body mass index (BMI), cigarette consumption, duration of COPD, annual hospitalization, dyspnea, glycated hemoglobin (HbA1c), FEV1, and FEV1/FVC indices.

RESULT

The mean age of the participants was 63.92 ± 10.75 years. There was a significant difference in the hospitalization between the patients with both exacerbation and normal state of COPD (P ≤ 0.001). HbA1c in the patients with exacerbation of COPD was significantly higher than stable status (P = 0.001). Logistic regression showed that HbA1c levels and hospitalization were predictors of exacerbation of COPD. HbA1c levels were statistically significant in terms of hospitalization in patients with COPD exacerbation. There was a significant difference between the HbA1c levels and MMRC in patients with COPD. The percentage of HbA1c was associated with exacerbation of COPD and HbA1c is a good predictor of disease severity in patients with COPD. It also shows that patients with COPD exacerbation and severe COPD are at the higher risk of hyperglycemia.

Bacterial and Viral Infection in Patients Hospitalized for Acute Exacerbation of Chronic Obstructive Pulmonary Disease: Implication for Antimicrobial Management and Clinical Outcome

Patients with chronic obstructive pulmonary disease (COPD) exhibit frequent acute exacerbations (AE). The objectives of this study were first to evaluate the prevalence of pathogens associated to these episodes by combining conventional bacteriology and multiplex viral and bacterial PCR assays in sputum specimens, and second to determine whether C-reactive protein (CRP) value and clinical outcome could be influenced by the type of microbial agent(s) recovered from these samples. A cohort of 84 Tunisian patients hospitalized at the emergency room for AECOPD was investigated prospectively for the semi-quantitative detection of bacteria by conventional culture (the threshold of positivity was of 107 CFU/ml) and for the detection of viral genome and DNA of atypical bacteria by quantitative PCR using two commercial multiplex respiratory kits (Seegene and Fast-track). The two kits exhibited very similar performances although the Seegene assay was a bit more sensitive. A large number and variety of pathogens were recovered from the sputum samples of these 84 patients, including 15 conventional bacteria, one Chlamydia pneumoniae and 63 respiratory viruses, the most prevalent being rhinoviruses (n = 33) and influenza viruses (n = 13). From complete results available for 74 patients, the presence of bacteria was significantly associated with risk of recurrence at 6 and 12 months post-infection. The combination of these different markers appears useful for delineating correctly the antimicrobial treatment and for initiating a long-term surveillance in those patients with high risk of recurrent exacerbation episodes. A prospective study is required for confirming the benefits of this strategy aimed at improving the stewardship of antibiotics.

Prevalence of Chlamydophila pneumoniae and Mycoplasma pneumoniae IgM and IgG antibodies in Tunisian patients presenting with exacerbation of chronic obstructive pulmonary disease

OBJECTIVE

We aimed to assess the prevalence of Chlamydophila pneumoniae and Mycoplasma pneumoniae acute infections, using serological testing, in patients admitted to the emergency department for acute exacerbations of chronic obstructive pulmonary disease (COPD).

METHODS

We performed a prospective observational study of 100 consecutive patients. Serum specimens were collected at day 0 and day 15. C. pneumoniae and M. pneumoniae antibodies (IgM and IgG) were tested by commercial ELISA and immunofluorescence assay, respectively.

RESULTS

We did not observe any acute M. pneumoniae infection; however, 11 patients (11%) showed a profile compatible with a recent C. pneumoniae infection (nine patients with specific IgM and two with an IgG antibody rise). Demographic and clinical parameters did not differ between patients with and without biological profile of recent C. pneumoniae infection.

CONCLUSION

C. pneumoniae is a pathogen that requires specific antimicrobial treatment. Its detection must always be performed considering its prevalence in patients presenting with acute COPD exacerbations.

Relationship Among Chlamydia and Mycoplasma Pneumoniae Seropositivity, IKZF1 Genotype and Chronic Obstructive Pulmonary Disease in A General Japanese Population: The Nagahama Study

Chronic obstructive pulmonary disease (COPD) is a possible risk factor for cardiovascular disease. The association of COPD with the pathogenicity of infection with Chlamydia pneumoniae and Mycoplasma pneumoniae is controversial. We conducted a cross-sectional study to clarify the association between atypical pneumoniae seropositivity and COPD in a general population. We also investigated genetic polymorphisms conferring susceptibility to a pneumonia titer. The study included 9040 Japanese subjects (54 ± 13 years). COPD was defined as a ratio of forced expiratory volume in 1 second to forced vital capacity of less than 70%. Serum levels of IgA and IgG antibodies to C pneumoniae were determined using an enzyme-linked immunoassay, and M pneumoniae seropositivity was assessed by a particle agglutination test. Subjects seropositive for C pneumoniae (26.1%) had a higher prevalence of COPD (seropositive, 5.8%; seronegative, 3.1%; P < 0.001) after adjustment for age, sex, height, weight, and smoking status. The association between M pneumoniae seropositivity (20.4%) and COPD was also significant in covariate-adjusted analysis (P < 0.001). A genome-wide association analysis of the C pneumoniae IgA index identified a susceptible genotype (rs17634369) near the IKZF1 gene, and the seropositive rate of C pneumoniae significantly differed among genotypes (AA, 22.5; AG, 25.3; GG, 29.7%, P < 0.001). On multiple regression analysis, seropositivity for both C pneumoniae (odds ratio = 1.41, P = 0.004) and M pneumoniae (odds ratio = 1.60, P = 0.002) was an independent determinant for COPD, while no direct association was found with the rs17634369 genotype. Seropositivity for both C pneumoniae and M pneumoniae is an independent risk factor for COPD in the general population.

A double-blind, randomised, placebo-controlled study of roxithromycin and doxycycline combination, roxithromycin alone, or matching placebo for 12 weeks in adults with frequent exacerbations of chronic obstructive pulmonary disease

Background

Azithromycin prophylaxis has been shown to reduce COPD exacerbations but there is poor evidence for other antibiotics. We compared exacerbation rates in COPD patients with a history of frequent exacerbations (at least three moderate or severe COPD exacerbations in the past two years) during a 12-week treatment course and over a subsequent 48-week follow up period.

Results

292 patients were randomised to one of three treatments for 12 weeks: roxithromycin 300 mg daily and doxycycline 100 mg daily (n = 101); roxithromycin 300 mg daily (n = 97); or matching placebos (n = 94). There were no differences in the annualised moderate and severe exacerbation rates after treatment with roxithromycin/doxycycline (2.83 (95 % CI 2.37-3.40)) or roxithromycin only (2.69 (2.26-3.21)) compared to placebo (2.5 (2.08-3.03)) (p = 0.352 and p = 0.5832 respectively). Furthermore, there were no differences in the annualised exacerbation rates during 12-week treatment with roxithromycin/doxycycline (1.64 (95 % CI 1.17-2.30)), roxithromycin only (1.75 (1.24-2.41)) or placebo (2.23 (1.68-3.03)) (p = 0.1709 and p = 0.2545 respectively). There were also no significant differences between groups for spirometry or quality of life scores over either the 12-week treatment or 48-week post-treatment periods. Both active treatments were associated with nausea but otherwise adverse events were comparable among treatment groups.

Conclusions

Twelve-weeks of prophylaxis with roxithromycin/doxycycline combination or roxithromycin alone did not reduce COPD exacerbations in patients with history of frequent exacerbations. These findings do not support the use of these antibiotics to prevent exacerbations in COPD patients.

Electronic supplementary material

The online version of this article (doi:10.1186/s12952-015-0034-8) contains supplementary material, which is available to authorized users.

Recombinant Cpn 0810 stimulates proinflammatory cytokine expression and apoptosis in human monocytes

The aim of the present study was to express the recombinant Chlamydophila pneumoniae (C. pneumoniae) protein, Cpn 0810, in Escherichia coli (E. coli) BL21, and investigate the effects of Cpn 0810 on inflammatory and apoptotic processes in human monocytic (THP-1) cells. An ELISA was performed to detect the levels of the proinflammatory cytokines, tumor necrosis factor (TNF)-α and interleukin (IL)-6. In addition, Hoechst 33258 staining and annexin V binding analyses were performed to measure the rates of apoptosis. Purified glutathione S-transferase (GST)-Cpn 0810 recombinant proteins were obtained from the E. coli BL21 cells carrying the pGEX6p-2/Cpn 0810 plasmid, and were shown to stimulate the expression of TNF-α and IL-6 in the THP-1 cells in a dose- and time-dependent manner. TNF-α and IL-6 levels peaked at 24 h after GST-Cpn 0810 stimulation. Furthermore, GST-Cpn 0810 significantly promoted the apoptosis of THP-1 cells. In conclusion, recombinant GST-Cpn 0810 was shown to stimulate the expression of TNF-α and IL-6, inhibit proliferation and induce apoptosis in THP-1 cells. Therefore, Cpn 0810 may interact with host cells following C. pneumoniae infection, functioning as an important pathogenic factor.

Infectious etiology of acute exacerbations in severe COPD patients

OBJECTIVES

Since the new GOLD guidelines were implemented no data have been published about the etiology of acute exacerbations (AECOPD) in severe COPD patients with a different frequency of annual episodes.

METHODS

One hundred and eleven COPD patients (FEV1 < 50%) were prospectively followed up for a year. Good-quality sputum samples recovered during AECOPD were processed, including quantitative culture and PCR detection of atypical bacteria.

RESULTS

A total of 188 sputum samples were obtained from AECOPD episodes. Forty patients had a single episode, and 71 patients had ≥2. In 128 episodes a single pathogen was isolated, while 42 episodes were polymicrobial (≥2 pathogens). Overall, the most frequent pathogen isolated was Pseudomonas aeruginosa (n = 54), followed by Haemophilus influenzae (n = 37), Streptococcus pneumoniae (n = 31), Moraxella catarrhalis (n = 29) and Staphylococcus aureus (n = 12). P. aeruginosa was the most frequent in both groups of patients (35% and 27% in those with 1 and ≥2 AECOPD, respectively). H. influenzae was associated with patients with a single annual AECOPD (33% vs. 16%; P = 0.006), while Enterobacteriaceae were associated with frequent exacerbators (0% vs. 12%; P < 0.044).

CONCLUSION

Overall, P. aeruginosa was the most frequent pathogen isolated from exacerbations. However, different bacterial etiology was observed depending on the number of annual episodes.

Severity of allergic airway disease due to house dust mite allergen is not increased after clinical recovery of lung infection with Chlamydia pneumoniae in mice

Chlamydia pneumoniae is associated with chronic inflammatory lung diseases like bronchial asthma and chronic obstructive pulmonary disease. The existence of a causal link between allergic airway disease and C. pneumoniae is controversial. A mouse model was used to address the question of whether preceding C. pneumoniae lung infection and recovery modifies the outcome of experimental allergic asthma after subsequent sensitization with house dust mite (HDM) allergen. After intranasal infection, BALB/c mice suffered from pneumonia characterized by an increased clinical score, reduction of body weight, histopathology, and a bacterial load in the lungs. After 4 weeks, when infection had almost resolved clinically, HDM allergen sensitization was performed for another 4 weeks. Subsequently, mice were subjected to a methacholine hyperresponsiveness test and sacrificed for further analyses. As expected, after 8 weeks, C. pneumoniae-specific antibodies were detectable only in infected mice and the titer was significantly higher in the C. pneumoniae/HDM allergen-treated group than in the C. pneumoniae/NaCl group. Intriguingly, airway hyperresponsiveness and eosinophilia in bronchoalveolar lavage fluid were significantly lower in the C. pneumoniae/HDM allergen-treated group than in the mock/HDM allergen-treated group. We did observe a relationship between experimental asthma and chlamydial infection. Our results demonstrate an influence of sensitization to HDM allergen on the development of a humoral antibacterial response. However, our model demonstrates no increase in the severity of experimental asthma to HDM allergen as a physiological allergen after clinically resolved severe chlamydial lung infection. Our results rather suggest that allergic airway disease and concomitant cellular changes in mice are decreased following C. pneumoniae lung infection in this setting.

In silico synteny based comparative genomics approach for identification and characterization of novel therapeutic targets in Chlamydophila pneumoniae

Chlamydophila pneumoniae is one of the most important and well studied gram negative bacterial strain with respect to community acquired pneumonia and other respiratory diseases like Chronic obstructive pulmonary disease (COPD), Chronic asthma, Alzheimer's disease, Atherosclerosis and Multisclerosis which have a great potential to infect humans and many other mammals. According to WHO prediction, COPD is to become the third leading cause of death by 2030. Unfortunately, the molecular mechanisms leading to chronic infections are poorly understood and the difficulty in culturing C pneumoniae in experimental conditions and lack of entirely satisfactory serological methods for diagnosis is also a hurdle for drug discovery and development. We have performed an insilico synteny based comparative genomics analysis of C pneumoniae and other eight Chlamydial organisms to know the potential of C pneumoniae which cause COPD but other Chlamydial organisms lack in potential to cause COPD though some are involved in human pathogenesis. We have identified total 354 protein sequences as non-orthologous to other Chlamydial organisms, except hypothetical proteins 70 were found functional out of which 60 are non homologous to Homo sapiens proteome and among them 18 protein sequences are found to be essential for survival of the C pneumoniae based on BLASTP search against DEG database of essential genes. CELLO analysis results showed that about 80% proteins are found to be cytoplasmic, Among which 5 were found as bacterial exotoxins and 2 as bacterial endotoxins, remaining 11 proteins were found to be involved in DNA binding, RNA binding, catalytic activity, ATP binding, oxidoreductase activity, hydrolase activity and proteolysis activity. It is expected that our data will facilitate selection of C pneumoniae proteins for successful entry into drug design pipelines.

Immunogenicity of Cpn0425 and its localization in cells infected with Chlamydophila pneumoniae

The present study aimed to determine the intracellular localization of Cpn0425 in Chlamydophila pneumoniae-infected cells. The recombinant plasmid pGEX-6p/Cpn0425 was transformed into E.coli Bl21 cells to express the fusion protein. Following purification with glutathione S-transferase (GST) resin chromatography, the Cpn0425 fusion protein was used to induce immunity in mice to develop monoclonal and polyclonal antibodies, which were subsequently used to localize the endogenous Cpn0425 protein by indirect immunofluorescence assay (IFA). ELISA was used to determine the immunogenicity of the Cpn0425 plasmid protein by recognizing the pool sera of patients infected with Chlamydia trachomatis and the pool sera of mice immunized with the Cpn0425 fusion protein. The Cpn0425 gene was expressed as the GST-Cpn0425 fusion protein in E. coli and its antibody was prepared by immunizing mice with the fusion protein. An anti-GST-Cpn0425 antibody was used to localize the protein in cells infected with Chlamydophila pneumoniae AR-39 using an IFA. The anti-GST-CT058 antibody detected an inclusion signal in the IFA. Cpn0425 protein strongly reacted with antiserum. Although Cpn0425 protein is not a secreted protein, it has good immunogenicity. Therefore, this protein may be useful for developing vaccines against Chlamydophila pneumoniae infection.

Caspase-1 dependent IL-1β secretion is critical for host defense in a mouse model of Chlamydia pneumoniae lung infection

Chlamydia pneumoniae (CP) is an important human pathogen that causes atypical pneumonia and is associated with various chronic inflammatory disorders. Caspase-1 is a key component of the ‘inflammasome’, and is required to cleave pro-IL-1β to bioactive IL-1β. Here we demonstrate for the first time a critical requirement for IL-1β in response to CP infection. Caspase-1^−/− mice exhibit delayed cytokine production, defective clearance of pulmonary bacteria and higher mortality in response to CP infection. Alveolar macrophages harbored increased bacterial numbers due to reduced iNOS levels in Caspase-1^−/− mice. Pharmacological blockade of the IL-1 receptor in CP infected wild-type mice phenocopies Caspase-1-deficient mice, and administration of recombinant IL-1β rescues CP infected Caspase-1^−/− mice from mortality, indicating that IL-1β secretion is crucial for host immune defense against CP lung infection. In vitro investigation reveals that CP-induced IL-1β secretion by macrophages requires TLR2/MyD88 and NLRP3/ASC/Caspase-1 signaling. Entry into the cell by CP and new protein synthesis by CP are required for inflammasome activation. Neither ROS nor cathepsin was required for CP infection induced inflammasome activation. Interestingly, Caspase-1 activation during CP infection occurs with mitochondrial dysfunction indicating a possible mechanism involving the mitochondria for CP-induced inflammasome activation.

Antibody response to chlamydiae in children with asthma and respiratory illness

No relation between the occurrence of antibodies to chlamydial agents and asthma in children was found. In asthmatic children, the antibodies to Chlamydia trachomatis occurred in 3.1% and to Chlamydophila pneumoniae in 22.7%, whereas in a control group of children without asthma or other allergic disease in 2.3% and 24.0%, respectively. The occurrence of antibodies of IgA and IgG classes to C. pneumoniae was also very similar; its rise was age-dependent. On the other hand, in the group of children in a pre-school age with respiratory tract infection, anti-chlamydial antibodies were demonstrated significantly more often (18.5% of IgG antibodies to C. trachomatis, 20.0% of IgM antibodies to both C. trachomatis and C. pneumoniae) than in those suffering from other, non-respiratory illness (3.9% of the former and 5.9% of the latter antibodies). However, in these children, we did not succeed in detection of C. trachomatis in conjunctival and nasopharyngeal smears by PCR. Nevertheless, chlamydial agents (C. trachomatis in infants, C. pneumoniae in pre-school children) should be taken into consideration in a differential diagnosis of respiratory tract inflammation.

Serological evidence of Mycoplasma pneumoniae infection in patients with acute exacerbation of COPD: analysis of 100 hospitalizations

PURPOSE

A prospective study was conducted in order to investigate the serologic evidence of Mycoplasma pneumoniae infection in Greek hospitalized patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD). Furthermore, we have assessed the frequency of a number of variables in the group of patients with a serological diagnosis of an acute M. pneumoniae infection compared to patients in whom M. pneumoniae infection was not documented.

MATERIALS/METHODS

One hundred patients with AECOPD were enrolled in a 29- month study period. Serum IgG, IgA and IgM M. pneumoniae antibody titers were determined during the first day of their hospitalization and 30 days after enrolment, using a commercial ELISA.

RESULTS

Nine patients (9%) had serological evidence of an acute M. pneumoniae infection. Acute infection was mainly documented by IgA antibody titer changes. It was mainly attributed to a reinfection rather than a primary infection. Patients with serological evidence of an acute M. pneumoniae infection had a higher heart rate (99±12 versus 88±14 beats/minute, p=0.02) and a higher hematocrit value (47±4.5% versus 40.4±6.2%, p=0.004) at admission than patients without a serological diagnosis for this pathogen.

CONCLUSIONS

Serologic evidence of M. pneumoniae infection is rather common in Greek hospitalized patients with AECOPD. The determination of all three antibody classes was necessary in order to obtain an optimal level of serodiagnosis. No differences were found in the majority of characteristics of patients with and without serological evidence for this pathogen. The clinical utility of these results should be further clarified in future studies.

Ectopic lymphoid tissue formation in the lungs of mice infected with Chlamydia pneumoniae is associated with epithelial macrophage inflammatory protein-2/CXCL2 expression

Infection with Chlamydia pneumoniae (Cp) accounts for around 10% of community acquired bacterial pneumonia and has been associated with other chronic inflammatory conditions. We describe a C57/Bl6 murine model of Cp lung infection characterized by a dose-dependent, resolving neutrophilia followed by lymphocytic infiltration of the lungs. By 21 days post-infection, mice exhibit a T helper type 1 (Th1) polarized serum antibody response with local mucosal antibody secretion and organization of ectopic lymphoid tissue which persisted in the absence of detectable Cp DNA. Macrophage inflammatory protein (MIP)-2/CXCL2, which recruits neutrophils and lymphocytes and is associated with ectopic lymphoid tissue formation, was secreted in the lungs post-infection. In vitro, lung epithelial cells up-regulated MIP-2/CXCL2 in response to both rough lipopolysaccharide (reLPS) and Cp infection. We conclude that Cp infection can have long-term inflammatory effects on tissue that persist after clearance of active infection.