[Analysis of epidemiological characteristics of respiratory pathogens in children with influenza-like illnesses in a children's hospital in Beijing from 2022 to 2023].

To investigate the status and epidemiological characteristics of respiratory pathogens infections in children with influenza-like illnesses (ILI) in Beijing Children's Hospital from 2022 to 2023. A dual amplification technique was used to detect nucleic acids of seven common respiratory pathogens, including influenza A virus (Flu A), influenza B virus (Flu B), mycoplasma pneumoniae (MP), respiratory syncytial virus (RSV), parainfluenza virus (PIV), adenovirus (ADV), and Chlamydia pneumoniae (CP), in outpatient and inpatient children (aged 0-18 years) with influenza-like symptoms who sought medical care at Beijing Children's Hospital, from January 2022 to March 2023. A total of 43 663 children were included in the study, of which 27 903 tested positive for respiratory pathogens with a total detection rate of 63.91%. Flu A had the highest detection rate of 69.93% (27 332/39 084), followed by MP about 13.22% (380/2 875). The total detection rate of RSV, PIV and ADV was 7.69% (131/1 704). Flu B had a detection rate of 0.16% (64/39 084). No CP was detected in this study. A total of 7 cases of dual infections were detected, with a detection rate of 0.41% (7/1 704). The Chi-square test was used to analyze the differences in detection rates of pathogens among different genders, age groups, and different seasons. Among the seven pathogens, only Flu A had statistically significant differences in gender (χ2=16.712, P<0.001). The detection rates of Flu A and MP showed an increasing trend with age (both P trend<0.001), while the detection rates of RSV and PIV showed a decreasing trend with age (both P trend<0.001). Flu A had its epidemic peak in winter and spring, with detection rates of 61.30% (3 907/6 374) and 77.47% (23 207/29 958) respectively; MP and PIV had higher detection rates in autumn (25.14% and 7.64% respectively); RSV showed a relatively higher detection rate in winter (8.69%); Flu B and ADV had lower detection rates throughout the study period (0.16% and 1.17% respectively). In conclusion, children with ILI in 2022-2023 were mainly infected with a single respiratory pathogen, and occasionally dual pathogen infections were observed. Among them, the detection rate of Flu A was the highest, and only Flu A showed a gender difference in detection rate. As the age of the children patients increased, the detection rate of Flu A and MP showed an increasing trend, while RSV and PIV showed a decreasing trend. The prevalence of Flu A, Flu B, MP, PIV, and RSV were seasonal.

Atypical bacterial co-infections among patients with COVID-19: A study from India.

Emerging evidence shows co-infection with atypical bacteria in coronavirus disease 2019 (COVID-19) patients. Respiratory illness caused by atypical bacteria such as Mycoplasma pneumoniae, Chlamydia pneumoniae, and Legionella pneumophila may show overlapping manifestations and imaging features with COVID-19 causing clinical and laboratory diagnostic issues. We conducted a prospective study to identify co-infections with SARS-CoV-2 and atypical bacteria in an Indian tertiary hospital. From June 2020 to January 2021, a total of 194 patients with laboratory-confirmed COVID-19 were also tested for atypical bacterial pathogens. For diagnosing M. pneumoniae, a real-time polymerase chain reaction (PCR) assay and serology (IgM ELISA) were performed. C. pneumoniae diagnosis was made based on IgM serology. L. pneumophila diagnosis was based on PCR or urinary antigen testing. Clinical and epidemiological features of SARS-CoV-2 and atypical bacteria-positive and -negative patient groups were compared. Of the 194 patients admitted with COVID-19, 17 (8.8%) were also diagnosed with M. pneumoniae (n = 10) or C. pneumoniae infection (n = 7). Confusion, headache, and bilateral infiltrate were found more frequently in the SARS CoV-2 and atypical bacteria co-infection group. Patients in the M. pneumoniae or C. pneumoniae co-infection group were more likely to develop ARDS, required ventilatory support, had a longer hospital length of stay, and higher fatality rate compared to patients with only SARS-CoV-2. Our report highlights co-infection with bacteria causing atypical pneumonia should be considered in patients with SARS-CoV-2 depending on the clinical context. Timely identification of co-existing pathogens can provide pathogen-targeted treatment and prevent fatal outcomes of patients infected with SARS-CoV-2 during the current pandemic.

Chlamydia pneumoniae-associated pleuropericarditis: a case report and systematic review of the literature.

BACKGROUND: Chlamydia pneumoniae is a common cause of atypical community acquired pneumonia (CAP). The diagnostic approach of chlamydial infections remains a challenge. Diagnosis of delayed chlamydial-associated complications, involving complex autoimmune pathophysiological mechanisms, is still more challenging. C. pneumoniae-related cardiac complications have been rarely reported, including cases of endocarditis, myocarditis and pericarditis. CASE PRESENTATION: A 40-year old female was hospitalized for pleuropericarditis following lower respiratory tract infection. The patient had been hospitalized for CAP (fever, dyspnea, chest X-ray positive for consolidation on the left upper lobe) 5 weeks ago and had received ceftriaxone and moxifloxacin. Four weeks after her discharge, the patient presented with fever, shortness of breath and pleuritic chest pain and was readmitted because of pericardial and bilateral pleural effusions (mainly left). The patient did not improve on antibiotics and sequential introduction of colchicine and methylprednisolone was performed. The patient presented impressive clinical and laboratory response. Several laboratory and clinical assessments failed to demonstrate any etiological factor for serositis. Chlamydial IgM and IgG antibodies were positive and serial measurements showed increasing kinetics for IgG. Gold standard polymerase chain reaction of respiratory tract samples was not feasible but possibly would not have provided any additional information since CAP occurred 5 weeks ago. The patient was discharged under colchicine and tapered methylprednisolone course. During regular clinic visits, she remained in good clinical condition without pericardial and pleural effusions relapse. CONCLUSIONS: C. pneumoniae should be considered as possible pathogen in case of pleuritis and/or pericarditis during or after a lower respiratory tract infection. In a systematic review of the literature only five cases of C. pneumoniae associated pericarditis were identified. Exact mechanisms of cardiovascular damage have not yet been defined, yet autoimmune pathways might be implicated.

In Vitro Activity of Omadacycline against Chlamydia pneumoniae.

The in vitro activities of omadacycline, azithromycin, doxycycline, moxifloxacin, and levofloxacin were tested against 15 isolates of Chlamydia pneumoniae The minimum inhibitory concentration at which 90% of the isolates of C. pneumoniae were inhibited by omadacycline was 0.25 µg/ml (range, 0.03 to 0.5 µg/ml).

Identfication of viral and bacterial etiologic agents of the pertussis-like syndrome in children under 5 years old hospitalized.

BACKGROUND: Acute respiratory infections (ARIs) represent an important cause of morbidity and mortality in children, remaining a major public health concern, especially affecting children under 5 years old from low-income countries. Unfortunately, information regarding their epidemiology is still limited in Peru. METHODS: A secondary data analysis was performed from a previous cross-sectional study conducted in children with a probable diagnosis of Pertussis from January 2010 to July 2012. All samples were analyzed via Polymerase Chain Reaction (PCR) for the following etiologies: Influenza-A, Influenza-B, RSV-A, RSV-B, Adenovirus, Parainfluenza 1 virus, Parainfluenza 2 virus, Parainfluenza 3 virus, Mycoplasma pneumoniae and Chlamydia pneumoniae. RESULTS: A total of 288 patients were included. The most common pathogen isolated was Adenovirus (49%), followed by Bordetella pertussis (41%) from our previous investigation, the most prevelant microorganisms were Mycoplasma pneumonia (26%) and Influenza-B (19.8%). Coinfections were reported in 58% of samples and the most common association was found between B. pertussis and Adenovirus (12.2%). CONCLUSIONS: There was a high prevalence of Adenovirus, Mycoplasma pneumoniae and other etiologies in patients with a probable diagnosis of pertussis. Despite the presence of persistent cough lasting at least two weeks and other clinical characteristics highly suspicious of pertussis, secondary etiologies should be considered in children under 5 years-old in order to give a proper treatment.

Antibiotic Use and Respiratory Pathogens in Adults With Sickle Cell Disease and Acute Chest Syndrome.

Background: Acute chest syndrome (ACS) is an acute complication of sickle cell disease (SCD). Historically, the most common pathogens were Chlamydophila pneumoniae, Mycoplasma pneumoniae, and respiratory syncytial virus. Pediatric patients receiving guideline-adherent therapy experienced fewer ACS-related and all-cause 30-day readmissions compared with those receiving nonadherent therapy. This has not been evaluated in adults. Objectives: The primary objectives were to characterize antibiotic use and pathogens. The secondary objective was to assess the occurrence of readmissions associated with guideline-adherent and clinically appropriate treatment compared with regimens that did not meet those criteria. Methods: A retrospective cohort analysis was conducted for adults with SCD hospitalized between August 1, 2014, and July 31, 2017, with pneumonia (PNA) or ACS. The study was approved by the institutional review board. Results: A total of 139 patients with 255 hospitalizations were reviewed. Among 41 respiratory cultures, 3 organisms were isolated: Cryptococcus neoformans, Pseudomonas aeruginosa, and budding yeast. Respiratory panels were collected on 121 admissions, with 17 positive for 1 virus; all were negative for Chlamydophila pneumoniae and M pneumoniae. There were significantly more ACS-/PNA-related 7-day readmissions from patients on guideline-adherent regimens compared with nonadherent regimens (3.7% vs 0%; P = 0.04). Conclusion and Relevance: These findings challenge existing knowledge regarding the most common pathogens in adults with SCD with ACS or PNA. Routine inclusion of a macrolide may not be necessary. Future studies focused on pathogen characterization with standardized assessment are necessary to determine appropriate empirical therapy in this population.

Detection of respiratory bacterial pathogens causing atypical pneumonia by multiplex Lightmix® RT-PCR.

Pneumonia is a severe infectious disease. In addition to common viruses and bacterial pathogens (e.g. Streptococcus pneumoniae), fastidious respiratory pathogens like Chlamydia pneumoniae, Mycoplasma pneumoniae and Legionella spp. can cause severe atypical pneumonia. They do not respond to penicillin derivatives, which may cause failure of antibiotic empirical therapy. The same applies for infections with B. pertussis and B. parapertussis, the cause of pertussis disease, that may present atypically and need to be treated with macrolides. Moreover, these fastidious bacteria are difficult to identify by culture or serology, and therefore often remain undetected. Thus, rapid and accurate identification of bacterial pathogens causing atypical pneumonia is crucial. We performed a retrospective method evaluation study to evaluate the diagnostic performance of the new, commercially available Lightmix® multiplex RT-PCR assay that detects these fastidious bacterial pathogens causing atypical pneumonia. In this retrospective study, 368 clinical respiratory specimens, obtained from patients suffering from atypical pneumonia that have been tested negative for the presence of common agents of pneumonia by culture and viral PCR, were investigated. These clinical specimens have been previously characterized by singleplex RT-PCR assays in our diagnostic laboratory and were used to evaluate the diagnostic performance of the respiratory multiplex Lightmix® RT-PCR. The multiplex RT-PCR displayed a limit of detection between 5 and 10 DNA copies for different in-panel organisms and showed identical performance characteristics with respect to specificity and sensitivity as in-house singleplex RT-PCRs for pathogen detection. The Lightmix® multiplex RT-PCR assay represents a low-cost, time-saving and accurate diagnostic tool with high throughput potential. The time-to-result using an automated DNA extraction device for respiratory specimens followed by multiplex RT-PCR detection was below 4 h, which is expected to significantly improve diagnostics for atypical pneumonia-associated bacterial pathogens.

Atypical pathogens in hospitalized patients with community-acquired pneumonia: a worldwide perspective.

BACKGROUND: Empirical antibiotic coverage for atypical pathogens in community-acquired pneumonia (CAP) has long been debated, mainly because of a lack of epidemiological data. We aimed to assess both testing for atypical pathogens and their prevalence in hospitalized patients with CAP worldwide, especially in relation with disease severity. METHODS: A secondary analysis of the GLIMP database, an international, multicentre, point-prevalence study of adult patients admitted for CAP in 222 hospitals across 6 continents in 2015, was performed. The study evaluated frequency of testing for atypical pathogens, including L. pneumophila, M. pneumoniae, C. pneumoniae, and their prevalence. Risk factors for testing and prevalence for atypical pathogens were assessed through univariate analysis. RESULTS: Among 3702 CAP patients 1250 (33.8%) underwent at least one test for atypical pathogens. Testing varies greatly among countries and its frequency was higher in Europe than elsewhere (46.0% vs. 12.7%, respectively, p < 0.0001). Detection of L. pneumophila urinary antigen was the most common test performed worldwide (32.0%). Patients with severe CAP were less likely to be tested for both atypical pathogens considered together (30.5% vs. 35.0%, p = 0.009) and specifically for legionellosis (28.3% vs. 33.5%, p = 0.003) than the rest of the population. Similarly, L. pneumophila testing was lower in ICU patients. At least one atypical pathogen was isolated in 62 patients (4.7%), including M. pneumoniae (26/251 patients, 10.3%), L. pneumophila (30/1186 patients, 2.5%), and C. pneumoniae (8/228 patients, 3.5%). Patients with CAP due to atypical pathogens were significantly younger, showed less cardiovascular, renal, and metabolic comorbidities in comparison to adult patients hospitalized due to non-atypical pathogen CAP. CONCLUSIONS: Testing for atypical pathogens in patients admitted for CAP in poorly standardized in real life and does not mirror atypical prevalence in different settings. Further evidence on the impact of atypical pathogens, expecially in the low-income countries, is needed to guidelines implementation.

[A method for preparation of an endothelial cell monolayer sample from the blood vessel intima]. / Metod polucheniia preparata monosloia éndotelial'nykh kletok intimy krovenosnykh sosudov.

The paper describes the procedure to prepare endothelial cell monolayer samples from the vascular intima, which is suitable for studying various morphological processes. To obtain high-quality multicellular specimens, it is recommended to preliminarily remove excess tissue from the outside of the vessel and to free the intima; ways to dry the surface and to separate endothelial cells are examined. The paper gives the figures of specimens stained by the Romanowsky-Giemsa method and identifies factor VIII, an endothelial marker, and Chlamydia pneumoniae inclusions in the cytoplasm of endothelial cells.

Infection-mediated asthma: etiology, mechanisms and treatment options, with focus on Chlamydia pneumoniae and macrolides.

Asthma is a chronic respiratory disease characterized by reversible airway obstruction and airway hyperresponsiveness to non-specific bronchoconstriction agonists as the primary underlying pathophysiology. The worldwide incidence of asthma has increased dramatically in the last 40 years. According to World Health Organization (WHO) estimates, over 300 million children and adults worldwide currently suffer from this incurable disease and 255,000 die from the disease each year. It is now well accepted that asthma is a heterogeneous syndrome and many clinical subtypes have been described. Viral infections such as respiratory syncytial virus (RSV) and human rhinovirus (hRV) have been implicated in asthma exacerbation in children because of their ability to cause severe airway inflammation and wheezing. Infections with atypical bacteria also appear to play a role in the induction and exacerbation of asthma in both children and adults. Recent studies confirm the existence of an infectious asthma etiology mediated by Chlamydia pneumoniae (CP) and possibly by other viral, bacterial and fungal microbes. It is also likely that early-life infections with microbes such as CP could lead to alterations in the lung microbiome that significantly affect asthma risk and treatment outcomes. These infectious microbes may exacerbate the symptoms of established chronic asthma and may even contribute to the initial development of the clinical onset of the disease. It is now becoming more widely accepted that patterns of airway inflammation differ based on the trigger responsible for asthma initiation and exacerbation. Therefore, a better understanding of asthma subtypes is now being explored more aggressively, not only to decipher pathophysiologic mechanisms but also to select treatment and guide prognoses. This review will explore infection-mediated asthma with special emphasis on the protean manifestations of CP lung infection, clinical characteristics of infection-mediated asthma, mechanisms involved and antibiotic treatment outcomes.

Atypical bacterial etiology of acute respiratory infections and clinical characterizations among Iranian children.

Acute respiratory infections (ARIs) in children younger than 5 years of age are one of the leading causes of morbidity and mortality, particularly in developing countries. Mycoplasma pneumoniae and Chlamydophila pneumoniae are prevalent causative agents of ARIs, worldwide. We sought M. pneumoniae and C. pneumoniae in respiratory samples from Iranian children with ARIs.  From November 2014 to April 2015, respiratory samples of 150 children aged 1 month to 15 years old were screened for presence of M. pneumoniae and C. pneumoniae. Polymerase chain reaction (PCR) and culture methods were used to detect these bacteria in respiratory samples in the form of throat swabs and nasopharyngeal aspirates. A questionnaire containing demographic and clinical information has been filled up for all participants in this study. Our obtained data showed that out of 150 tested samples, 7 (4.7%) were PCR positive for M. pneumoniae and only one (0.7%) positive sample for C. pneumoniae was detected. However, none of the tested samples was detected M. pneumoniae using the bacterial culture method. All patients with ARIs due to M. pneumoniae showed up with sore throat and flu like symptoms. According to our data, PCR method is more sensitive than culture for detection of M. pneumoniae. With regards to our results, it appears that M. pneumoniae and especially C. pneumoniae were infrequent causative agents in our studied population.

Prevalence of Atypical Pathogens in Patients With Cough and Community-Acquired Pneumonia: A Meta-Analysis.

PURPOSE: Community-acquired pneumonia (CAP), acute cough, bronchitis, and lower respiratory tract infections (LRTI) are often caused by infections with viruses or Streptococcus pneumoniae. The prevalence of atypical pathogens Mycoplasma pneumoniae, Chlamydophila pneumoniae, Legionella pneumophila, and Bordetella pertussis among patients with these illnesses in the ambulatory setting has not been previously summarized. We set out to derive prevalence information from the existing literature. METHODS: We performed a systematic review of MEDLINE for prospective, consecutive-series studies reporting the prevalence of M pneumoniae, C pneumoniae, L pneumophila and/or B pertussis in outpatients with cough, acute bronchitis, LRTI, or CAP. Articles were independently reviewed by 2 authors for inclusion and abstraction of data; discrepancies were resolved by consensus discussion. A meta-analysis was performed on each pathogen to calculate the pooled prevalence estimates using a random effects model of raw proportions. RESULTS: Fifty studies met our inclusion criteria. While calculated heterogeneity was high, most studies reported prevalence for each pathogen within a fairly narrow range. In patients with CAP, the overall prevalences of M pneumoniae and C pneumoniae were 10.1% (95% CI, 7.1%-13.1%) and 3.5% (95% CI, 2.2%-4.9%), respectively. Consistent with previous reports, M pneumoniae prevalence peaked in roughly 6-year intervals. Overall prevalence of L pneumophila was 2.7% (95% CI, 2.0%-3.4%), but the organism was rare in children, with only 1 case in 1,765. In patients with prolonged cough in primary care, the prevalence of B pertussis was 12.4% (95% CI, 4.9%-19.8%), although it was higher in studies that included only children (17.6%; 95% CI, 3.4%-31.8%). CONCLUSIONS: Atypical bacterial pathogens are relatively common causes of lower respiratory diseases, including cough, bronchitis, and CAP. Where surveillance data were available, we found higher prevalences in studies where all patients are tested for these pathogens. It is likely that these conditions are underreported, underdiagnosed, and undertreated in current clinical practice.

The prevalence of Chlamydia pneumoniae in the aortic wall and in peripheral blood of patients scheduled for coronary artery bypass grafting.

Some reports confirm a potential role of Chlamydia pneumoniae (ChP) in atherogenesis. In order to explore possible association between ChP and atherosclerosis, investigations were carried out in which the frequency of ChP in the arterial wall and peripheral blood was assessed in a group of patients with chronic coronary artery disease (CAD). Fifty-seven patients were enrolled in the study, 13 women and 44 men aged 61.8±6.5 (47-74), with previously diagnosed CAD, scheduled for planned coronary artery bypass grafting due to clinical indications. Vessel specimens retrieved from the ascending aorta (as a part of routine proximal venous graft development procedure) and peripheral blood mononuclear cells (PBMCs) from venous blood were evaluated for the presence of ChP DNA. Genomic DNA was extracted from PBMCs and vessel specimens. Quantitative real-time polymerase chain reaction (qPCR) was performed to detect ChP DNA. A statistically more frequent occurrence of ChP was observed in aortic tissues compared to blood samples (70.2% vs 56.1%, respectively). Similarly, the number of ChP DNA genomic copies [n/1µg genomic DNA] was significantly higher in tissue specimens compared to blood samples (89±91 vs 41±77, respectively; p=0.0046). In patients without ChP in blood specimens, we observed significantly higher amounts of ChP in tissue specimens compared to patients with ChP in blood specimens (156±71 vs 107±88, respectively; p=0.0453). No correlation was found between the number of ChP DNA copies [n/1µg genomic DNA] in blood and in aortic specimens. The infection of ChP in the aortic wall was connected with hypercholesterolemia (p=0.029) and diabetes (p=0.03). We conclude that Chlamydia pneumoniae is a pathogen frequently occurring in the aortic wall of patients with CAD. The occurrence of ChP DNA in the aortic tissue is related to classic CAD risk factors such as diabetes and dyslipidemia.

Comparison of serological methods with PCR-based methods for the diagnosis of community-acquired pneumonia caused by atypical bacteria.

BACKGROUND: The diagnosis of community-acquired pneumonia (CAP) caused by Legionella pneumophila, Mycoplasma pneumoniae, and Chlamydophila pneumoniae is traditionally based on cultures and serology, which have special requirements, are time-consuming, and offer delayed results that limit their clinical usefulness of these techniques. We sought to develop a multiplex PCR (mPCR) method to diagnosis these bacterial infections in CAP patients and to compare the diagnostic yields obtained from mPCR of nasopharyngeal aspirates (NPAs), nasopharyngeal swabs (NPSs), and induced sputum (IS) with those obtained with specific PCR commercial kits, paired serology, and urinary antigen. RESULTS: A total of 225 persons were included. Of these, 10 patients showed serological evidence of L. pneumophila infection, 30 of M. pneumoniae, and 18 of C. pneumoniae; 20 individuals showed no CAP. The sensitivities were mPCR-NPS = 23.1%, mPCR-IS = 57.1%, Seeplex®-IS = 52.4%, and Speed-oligo®-NPA/NPS = 11.1%, and the specificities were mPCR-NPS = 97.1%, mPCR-IS = 77.8%, Seeplex®-IS = 92.6%, and Speed-oligo®-NPA/NPS = 96.1%. The concordance between tests was poor (kappa <0.4), except for the concordance between mPCR and the commercial kit in IS (0.67). In individuals with no evidence of CAP, positive reactions were observed in paired serology and in all PCRs. CONCLUSIONS: All PCRs had good specificity but low sensitivity in nasopharyngeal samples. The sensitivity of mPCR and Seeplex® in IS was approximately 60%; thus, better diagnostic techniques for these three bacteria are required.

Pathogens Causing Upper Respiratory Tract Infections in Outpatients.

The aim of the present study was to determine the results of typical and atypical bacteria microbiological tests in patients with symptoms of chronic cough. We investigated 230 outpatients aged from 1 to 83 years (112 female, 72 male, and 46 children) who were free of any respiratory tract infection at the time of study. The material for the investigation consisted of pharyngeal swabs. Two hundred and thirty pharyngeal swabs were examined for Chlamydia pneumoniae antigen and for typical pathogens each. Chlamydia pneumoniae antigen was detected using an indirect immunofluorescence test and classical microbiological culture was used for the detection of typical bacteria. The antigen was found in 44/230 (19.1 %) patients with chronic cough (23 women, 13 men, and 8 children). Positive culture for typical pathogens was observed in 65/230 (28.3 %) patients (37 women, 14 men, and 14 children). Simultaneous occurrence of Chlamydia pneumoniae and typical pathogens such as Staphylococcus aureus, Streptococcus pyogenes, Moraxella catarrhalis, and Haemophilus influenzae, was observed in 11/230 (4.8 %) patients. The results show that in patients with chronic cough Chlamydia pneumoniae is detected less frequently than the typical pathogens are. A search for atypical bacteria in patients with chronic cough is needed to be able to conduct effective and sufficiently long therapy.

Role of Chlamydia pneumoniae and Helicobacteria pylori in the development of tympanosclerosis.

The etiology of tympanosclerosis (TS) is not known, but TS commonly develops secondary to acute and chronic otitis media (COM). Since calcification process in TS resembles that of atherosclerosis (AS), pathogens that are related to pathogenesis of AS may be involved in development of TS. This prospective and controlled study, performed at a tertiary referral center, investigated a possible relationship between the presence of Chlamydia (C.) pneumoniae and Helicobacter (H.) pylori and the development of a tympanosclerotic plaque. The presence of C. pneumoniae was examined in the surgical specimens of 62 patients (29 females and 33 males; age range 10-70 years, mean age 30.8 ± 13.3 years), including 30 patients with TS, 14 patients with cholesteatoma, and 18 patients with chronic suppurative otitis media (CSOM). The presence of H. pylori was examined in the surgical specimens of 88 patients (41 females and 47 males; age range 6-70 years, mean age 32.5 ± 14.8 years), including 35 patients with TS, 22 patients with cholesteatoma, 20 patients with CSOM, and 11 patients with otosclerosis. Tympanosclerotic plaques and control specimens from the cholesteatoma, polypoid mucosa, or mucosal portion of the perforations and stapes supra structure were examined for the presence of H. pylori and/or C. pneumoniae using real-time polymerase chain reaction analysis. The analysis demonstrated that specimens from the tympanosclerotic plaques and the other types of COM were all negative for C. pneumoniae and H. pylori. An association between C. pneumoniae or H. pylori infection and the development of TS or other types of COM could not be established.

[Distribution characteristics of Mycoplasma pneumoniae, Chlamydia pneumoniae, and Legionella pneumophila in hospitalized children with acute respiratory tract infection: an analysis of 13 198 cases].

OBJECTIVE: To investigate the distribution characteristics of Mycoplasma pneumoniae (MP), Chlamydia pneumoniae (CP), and Legionella pneumophila (LP) in hospitalized children with acute respiratory tract infection (ARTI). METHODS: A total of 13 198 hospitalized children with ARTI were enrolled as study subjects. Whole blood and urine were collected. The passive agglutination was used to detect serum MP-IgM, ELISA was used to detect serum CP-IgM, and immunochromatography was performed to detect urinary LP antigen. RESULTS: Among the 13 198 hospitalized ARTI children, the detection rates of MP, CP, and LP were 25.31%, 12.74% and 3.27%, suggesting that MP had the highest detection rate (P<0.0125). The detection rates of MP in 2013 and 2014 were significantly higher than that in 2012 (P<0.0125). CP had the highest detection rate in 2013, and LP had the highest detection rate in 2014 (P<0.0125). These three pathogens were detected all around the year, and MP had the highest detection rate in all seasons (P<0.0125). The detection rate of mixed infection with three pathogens was 4.35%, and mixed infection with MP and CP was the most common (P<0.0071). Among the children in different age groups, the patients aged 5-16 years showed the highest overall detection rate of three pathogens (P<0.0071). Among the children with different types of ARTI, the children with bronchopneumonia showed the highest overall detection rate of three pathogens (P<0.0045). CONCLUSIONS: MP, CP, and LP, particularly MP, are important pathogens for children with ARTI in the local area. LP infection tends to increase year by year and should be taken seriously in clinical practice.

Genomic factors related to tissue tropism in Chlamydia pneumoniae infection.

BACKGROUND: Chlamydia pneumoniae (Cpn) are obligate intracellular bacteria that cause acute infections of the upper and lower respiratory tract and have been implicated in chronic inflammatory diseases. Although of significant clinical relevance, complete genome sequences of only four clinical Cpn strains have been obtained. All of them were isolated from the respiratory tract and shared more than 99% sequence identity. Here we investigate genetic differences on the whole-genome level that are related to Cpn tissue tropism and pathogenicity. RESULTS: We have sequenced the genomes of 18 clinical isolates from different anatomical sites (e.g. lung, blood, coronary arteries) of diseased patients, and one animal isolate. In total 1,363 SNP loci and 184 InDels have been identified in the genomes of all clinical Cpn isolates. These are distributed throughout the whole chlamydial genome and enriched in highly variable regions. The genomes show clear evidence of recombination in at least one potential region but no phage insertions. The tyrP gene was always encoded as single copy in all vascular isolates. Phylogenetic reconstruction revealed distinct evolutionary lineages containing primarily non-respiratory Cpn isolates. In one of these, clinical isolates from coronary arteries and blood monocytes were closely grouped together. They could be distinguished from all other isolates by characteristic nsSNPs in genes involved in RB to EB transition, inclusion membrane formation, bacterial stress response and metabolism. CONCLUSIONS: This study substantially expands the genomic data of Cpn and elucidates its evolutionary history. The translation of the observed Cpn genetic differences into biological functions and the prediction of novel pathogen-oriented diagnostic strategies have to be further explored.

Increased sensitivity to tryptophan bioavailability is a positive adaptation by the human strains of Chlamydia pneumoniae.

One of the most significant activities induced by interferon-gamma against intracellular pathogens is the induction of IDO (indoleamine 2,3-dioxygenase) expression, which subsequently results in the depletion of tryptophan. We tested the hypothesis that human strains of Chlamydia pneumoniae are more sensitive to tryptophan limitation than animal C. pneumoniae strains. The human strains were significantly more sensitive to IFN-γ than the animal strains in a lung epithelia cell model (BEAS-2B), with exposure to 1 U ml(-1) IFN-γ resulting in complete loss of infectious yield of human strains, compared to the animal strains where reductions in infectious progeny were around 3.5-4.0 log. Strikingly, the IFN-γ induced loss of ability to form infectious progeny production was completely rescued by removal of the IFN-γ and addition of exogenous tryptophan for the human strains, but not the animal strains. In fact, a human heart strain was more capable of entering a non-infectious, viable persistent stage when exposed to IFN-γ and was also more effectively rescued, compared to a human respiratory strain. Exquisite susceptibility to IFN-γ, specifically due to tryptophan availability appears to be a core adaptation of the human C. pneumoniae strains, which may reflect the chronic nature of their infections in this host.

Comparative analysis of the growth and biological activity of a respiratory and atheroma isolate of Chlamydia pneumoniae reveals strain-dependent differences in inflammatory activity and innate immune evasion.

BACKGROUND: Chlamydia pneumoniae is a common human pathogen that is associated with upper and lower respiratory tract infections. It has also been suggested that C. pneumoniae infection can trigger or promote a number of chronic inflammatory conditions, including asthma and atherosclerosis. Several strains of C. pneumoniae have been isolated from humans and animals, and sequence data demonstrates marked genetic conservation, leaving unanswered the question as to why chronic inflammatory conditions may occur following some respiratory-acquired infections. METHODS: C. pneumoniae strains AR39 and AO3 were used in vitro to infect murine bone marrow derived macrophages and L929 fibroblasts, or in vivo to infect C57BL/6 mice via the intranasal route. RESULTS: We undertook a comparative study of a respiratory isolate, AR39, and an atheroma isolate, AO3, to determine if bacterial growth and host responses to infection varied between these two strains. We observed differential growth depending on the host cell type and the growth temperature; however both strains were capable of forming plaques in vitro. The host response to the respiratory isolate was found to be more inflammatory both in vitro, in terms of inflammatory cytokine induction, and in vivo, as measured by clinical response and lung inflammatory markers using a mouse model of respiratory infection. CONCLUSIONS: Our data demonstrates that a subset of C. pneumoniae strains is capable of evading host innate immune defenses during the acute respiratory infection. Further studies on the genetic basis for these differences on both the host and pathogen side could enhance our understanding how C. pneumoniae contributes to the development chronic inflammation at local and distant sites.