Clinical identification and microbiota analysis of Chlamydia psittaci- and Chlamydia abortus- pneumonia by metagenomic next-generation sequencing.

Introduction: Recently, the incidence of chlamydial pneumonia caused by rare pathogens such as C. psittaci or C. abortus has shown a significant upward trend. The non-specific clinical manifestations and the limitations of traditional pathogen identification methods determine that chlamydial pneumonia is likely to be poorly diagnosed or even misdiagnosed, and may further result in delayed treatment or unnecessary antibiotic use. mNGS's non-preference and high sensitivity give us the opportunity to obtain more sensitive detection results than traditional methods for rare pathogens such as C. psittaci or C. abortus. Methods: In the present study, we investigated both the pathogenic profile characteristics and the lower respiratory tract microbiota of pneumonia patients with different chlamydial infection patterns using mNGS. Results: More co-infecting pathogens were found to be detectable in clinical samples from patients infected with C. psittaci compared to C. abortus, suggesting that patients infected with C. psittaci may have a higher risk of mixed infection, which in turn leads to more severe clinical symptoms and a longer disease course cycle. Further, we also used mNGS data to analyze for the first time the characteristic differences in the lower respiratory tract microbiota of patients with and without chlamydial pneumonia, the impact of the pattern of Chlamydia infection on the lower respiratory tract microbiota, and the clinical relevance of these characteristics. Significantly different profiles of lower respiratory tract microbiota and microecological diversity were found among different clinical subgroups, and in particular, mixed infections with C. psittaci and C. abortus resulted in lower lung microbiota diversity, suggesting that chlamydial infections shape the unique lung microbiota pathology, while mixed infections with different Chlamydia may have important effects on the composition and diversity of the lung microbiota. Discussion: The present study provides possible evidences supporting the close correlation between chlamydial infection, altered microbial diversity in patients' lungs and clinical parameters associated with infection or inflammation in patients, which also provides a new research direction to better understand the pathogenic mechanisms of pulmonary infections caused by Chlamydia.

A case of chlamydia psittaci caused severe pneumonia and meningitis diagnosed by metagenome next-generation sequencing and clinical analysis: a case report and literature review.

BACKGROUND: Psittacosis, which is also known as parrot fever, is Chlamydia psittaci (C. psittaci) caused infectious disease. The clinical manifestations vary from asymptomatic infection to severe atypical pneumonia or even fatal meningitis. Early recognition of psittacosis is difficult because of its nonspecific clinical manifestations. Culture and gene probe techniques for C. psittaci are not available for routine clinical use, which makes the diagnosis difficult too. Although psittacosis has increasingly been recognized and reported in recent years, cure of severe pneumonia complicated with meningitis, with etiologic diagnosis aided by the use of metagenomic next-generation sequencing (mNGS), is still uncommon. So, it is necessary to report and review such potentially fatal case. CASE PRESENTATION: This report describes a 54-year-old woman with C. psittaci caused severe atypical pneumonia and meningitis. She presented with symptoms of fever, dry cough and dyspnea, accompanied by prominent headache. Her condition deteriorated rapidly to respiratory failure and lethargy under the treatment of empirical antibacterial agents, and was treated with invasive mechanical ventilation soon. She denied contact with birds, poultry or horses, but unbiased mNGS of both the bronchoalveolar lavage fluid (BALF) and the cerebrospinal fluid (CSF) identified sequence reads corresponding to C. psittaci infection, and there was no sequence read corresponding to other probable pathogens. Combined use of targeted antimicrobial agents of tetracyclines, macrolides and fluoroquinolones was carried out, and the patient's condition improved and she was discharged home 28 days later. Her status returned close to premorbid condition on day 60 of follow-up. CONCLUSIONS: When clinicians come across a patient with atypical pneumonia accompanied by symptoms of meningitis, psittacosis should be taken into consideration. mNGS is a promising detection method in such condition and is recommended.

Co-infection of SARS-CoV-2 with Chlamydia or Mycoplasma pneumoniae: a case series and review of the literature.

INTRODUCTION: The novel coronavirus SARS-CoV-2 has spread all over the world causing a global pandemic and representing a great medical challenge. Nowadays, there is limited knowledge on the rate of co-infections with other respiratory pathogens, with viral co-infection being the most representative agents. Co-infection with Mycoplasma pneumoniae has been described both in adults and pediatrics whereas only two cases of Chlamydia pneumoniae have been reported in a large US study so far. METHODS: In the present report, we describe a series of seven patients where co-infection with C. pneumoniae (n = 5) or M. pneumoniae (n = 2) and SARS-CoV-2 was detected in a large teaching hospital in Rome. RESULTS AND CONCLUSION: An extensive review of the updated literature regarding the co-infection between SARS-CoV-2 and these atypical pathogens is also performed.

Naked-Eye Enumeration of Single Chlamydia pneumoniae Based on Light Scattering of Gold Nanoparticle Probe.

Chlamydia pneumoniae is a spherical zoonotic pathogen with a diameter of ∼200 nm, which can lead to a wide range of acute and chronic diseases in human body. Early and reliable on-site detection of C. pneumoniae is the key step to control the spread of the pathogen. However, the lack of a current technology with advantages of rapidity, ultrasensitivity, and convenience limits the implementation of traditional techniques for on-site detection of C. pneumoniae. Herein, we developed a naked-eye counting of C. pneumoniae based on the light scattering properties of gold nanoparticle (GNP) under dark-field microscopy (termed "GNP-labeled dark-field counting strategy"). The recognition of single C. pneumoniae by anti-C. pneumoniae antibodies-functionalized GNP probes with size of 15 nm leads to the formation of wreath-like structure due to the strong scattered light resulted from hundreds of GNP probes binding on one C. pneumoniae under dark-field microscopy. Hundreds of GNP probes can bind to the surface of C. pneumoniae due to the high stability and specificity of the nucleic acid immuno-GNP probes, which generates by the hybridization of DNA-modified GNP with DNA-functionalized antibodies. The limit of detection (LOD) of the GNP-labeled dark-field counting strategy for C. pneumoniae detection in spiked samples or real samples is down to four C. pneumoniae per microliter, which is about 4 times more sensitive than that of quantitative polymerase chain reaction (qPCR). Together with the advantages of the strong light scattering characteristic of aggregated GNPs under dark-field microscopy and the specific identification of functionalized GNP probes, we can detect C. pneumoniae in less than 30 min using a cheap and portable microscope even if the sample contains only a few targets of interest and other species at high concentration. The GNP-labeled dark-field counting strategy meets the demands of rapid detection, low cost, easy to operate, and on-site detection, which paves the way for early and on-site detection of infectious pathogens.

[Human Psittacosis: A Case Report]. / Psitacose: A Propósito de Um Caso Clínico.

Psittacosis is a rare disease caused by Chlamydophila psittaci, an intracellular bacteria transmitted by contaminated birds. The clinical and radiological presentations are nonspecific. We describe a case of a 42-year-old woman, with known exposure to birds, who presented to the emergency department with one-week evolution of myalgia, polyarthritis, and respiratory symptoms. At admission, she had fever, respiratory failure, raised inflammatory markers and bilateral interstitial infiltrates at chest radiography. Considering the clinical findings and epidemiological background, we raised the hypothesis of a Chlamydophila psittaci atypical pneumonia that was serologically confirmed. Tetracyclines are the mainstay of treatment and the macrolides are an effective alternative. We highlight the importance of the epidemiological context in the early diagnosis and treatment of this infection.

A psitacose é uma entidade rara provocada pela Chlamydophila psittaci, uma bactéria intracelular obrigatória que se transmite através do contacto com aves contaminadas. A apresentação clínica e imagiológica é inespecífica. Reporta-se o caso clínico de uma mulher de 42 anos, com história de exposição a pássaros, que se apresenta no Serviço de Urgência com um quadro de mialgias, poliartralgias e clínica de infeção respiratória, com uma semana de evolução. À admissão, encontrava-se febril, com insuficiência respiratória do tipo 1, elevação dos parâmetros inflamatórios e infiltrados intersticiais difusos bilaterais na radiografia de tórax. Considerando o quadro clínico e o contexto epidemiológico de risco, colocou-se a hipótese de pneumonia atípica por Chlamydophila psittaci, confirmada serologicamente. As tetraciclinas são o esteio do tratamento, sendo os macrólidos uma alternativa eficaz. Realça-se a importância do contexto epidemiológico, para uma abordagem diagnóstica e terapêutica apropriadas.

[Psittacosis - a forgotten diagnosis in Sweden?] / Ornitos är sannolikt under­diagnostiserad i Sverige - Rätt metodik krävs: 5 av 24 svenska mikrobiologiska laboratorier har konstaterat 96 procent av alla fall.

Psittacosis, parrot fever, is an infectious disease caused by Chlamydophila psittaci, a common pathogen among birds. The clinical course ranges from a mild flu-like illness to severe disease that requires intensive care in humans. We report three cases of severe pneumonia where C. psittaci was unexpectedly detected during routine validation of a new C. psittaci PCR assay. Psittacosis is a notifiable disease in Sweden and national statistics show that 96% of Swedish psittacosis cases were identified in five of the 24 microbiological laboratories available in the country. These five laboratories perform PCR for C. psittaci routinely in panels with other atypical pneumonia agents and/or Legionella, suggesting that psittacosis is an underdiagnosed infection in Sweden.

[Laboratory diagnosis of rare diseases]. / Labbdiagnostik av sällsynta sjukdomar kan bli bättre - Både metodernas tillförlitlighet och personalens medvetenhet spelar roll ­ ornitos är ett bra exempel.

Psittacosis (parrot fever) is underdiagnosed in Sweden, possibly due to lack of awareness, and the fact that only five out of 24 clinical microbiology laboratories routinely perform the PCR test for Chlamydia psittaci. The test has shown 100% sensitivity and 100% sensitivity for the pathogen in samples from the lower part of the respiratory tract which caters for a high predictive value in patients with symptoms and signs of community-acquired atypical pneumonias, provided optimal patient selection. Knowledge and awareness of treatable rare diseases amongst healthcare personnel combined with conveniently available cost-effective diagnostic techniques is essential for improvements in the handling of rare diseases.

Influence of different delivery modes on the clinical characteristics of Chlamydia trachomatis pneumonia.

We analyzed the effects of delivery methods on Chlamydia trachomatis pneumonia in infants. Three hundred forty-four children hospitalized with Chlamydia trachomatis pneumonia were enrolled. They were divided into the vaginal delivery group and the cesarean delivery group. We compared and analyzed their age of onset, peripheral blood white blood cell count, liver enzymes, chlamydia trachomatis titers, and chest radiograph scores. Seventy-eight (22.7%) were delivered by a cesarean, and 266 (77.3%) were delivered vaginally. There were no statistically significant differences between groups when compared by sex and age (P > 0.05). Copy numbers and white blood cell counts in the peripheral blood of children with Chlamydia trachomatis in respiratory secretions of the vaginal delivery group were significantly higher than those of the cesarean delivery group (P < 0.05). The alanine aminotransferase and aspartate aminotransferase levels between groups were not statistically significant. Comparisons of admission chest radiography scores, discharge radiography scores, and score differences showed no statistical differences (P > 0.05). CONCLUSION: Infants delivered by cesarean comprise approximately one-fifth of those affected. The Chlamydia trachomatis titers and peripheral blood leukocyte counts of the vaginal delivery group were higher than those of the cesarean delivery group. Age of onset, liver enzymes, pulmonary inflammation, and pneumonia absorption were not different between groups. What is Known: • Chlamydia trachomatis is an important pathogen that causes lower respiratory tract infections in infants. • C. trachomatis is primarily transmitted to infants through the infected mother, resulting in Chlamydia trachomatis pneumonia subsequently. What is New: • Vaginal delivery and cesarean delivery can result in Chlamydia trachomatis pneumonia transmission; however, cesarean delivery accounts for ~ 20% of cases. • C. trachomatis volume in the respiratory tract and the number of peripheral blood leukocytes in infants delivered vaginally were higher than those in infants delivered by cesarean.

Birds of a feather: an uncommon cause of pneumonia and meningoencephalitis.

A 61-year-old man was admitted with a 1-week history of influenza-like symptoms during a period of increased influenza virus activity. He soon developed type 2 respiratory failure and became increasingly drowsy. He later suffered a convulsive episode in the intensive care unit (ICU) which self-terminated. Initial clinical findings suggested community-acquired pneumonia and meningoencephalitis. However, a detailed history revealed that he was a pet bird-keeper, which raised a suspicion of ornithosis. Chlamydia psittaci DNA was detected in sputum by PCR. He was started on appropriate antibiotics and made a full recovery. We present this uncommon cause of pneumonia as an example of the importance of accurate history-taking to ensure a correct diagnosis for optimal management.

Chronic Infection and Severe Asthma.

Chronic bacterial infection is implicated in both the development and severity of asthma. The atypical bacteria Mycoplasma pneumoniae and Chlamydophila pneumoniae have been identified in the airways of asthmatics and correlated with clinical features such as adult onset, exacerbation risks, steroid sensitivity, and symptom control. Asthmatic patients with evidence of bacterial infection may benefit from antibiotic treatment directed towards these atypical organisms. Examination of the airway microbiome may identify microbial communities that confer risk for or protection from severe asthma.

[Chlamydia trachomatis infection in mother and child; the importance of a complete history and efficient interdisciplinary communication]. / Chlamydia trachomatis-infectie bij moeder en kind: Belang van een grondige familieanamnese en goed intercollegiaal overleg.

General practitioners and paediatricians are frequently confronted with coughing infants. The age of the infant, the history of both mother and child, as well as the current maternal condition may provide important diagnostic information. A 4-week-old male infant was referred to the paediatrician with a persistent cough. He was admitted to hospital with dyspnoea and need for supplemental oxygen. Meanwhile, his mother was admitted with unexplained abdominal pain and elevated laboratory inflammation markers. Her history revealed an ectopic pregnancy. The infant's condition, for which the initial differential diagnosis was viral bronchiolitis or whooping cough, deteriorated. His medical history revealed a purulent conjunctivitis. Chlamydia trachomatis PCR turned out to be positive in both mother and child. C. trachomatis pneumonia is a common, yet often overlooked cause of cough in infants. This clinical lesson emphasises the importance of a complete history and efficient communication between medical specialists.

[Bronchopulmonary infections caused by atypical pathogens in children : Myth or reality?] / Les infections broncho-pulmonaires à germes atypiques chez l'enfant : Mythe ou réalité ?

Mycoplasma pneumoniae and Chlamydia pneumoniae are the most common atypical pathogens seen in respiratory infections in children. Currently, the management of atypical pneumonia due to these pathogens is blurry. The clinical features are hardly specific ; it appears that M. pneumoniae respiratory infect ions are associated with chest pain and the absence of wheezing, however, further confirmations are needed. Hoarseness is frequently seen with C. pneumoniae infection. Co-infections with viruses, bacteria or even between M. pneumoniae and C. pneumoniae can be frequent. Infection with either of these bacteria seems to increase the incidence of asthma. PCR appears to be the most sensitive and specific for rapid diagnosis of M. pneumoniae and C. pneumoniae infections, however, it cannot dif ferentiate asymptomatic carriage from infection. Serodiagnosis can be helpful. This requires two serum samples taken with several weeks interval. Macrolides are the classical antibiotics used for treatment of these pathogens. In vivo efficacy of antibiotic treatment of M. pneumoniae remains unclear. Resistance to macrolides in M. pneumoniae treatment has been described. In conclusion, there is still a lack in scientific literature of high level evidences and clear consensus in the management of suspicious infection due to M. pneumoniae and C. pneumoniae.

Les germes atypiques les plus fréquemment rencontrés dans les infections respiratoires chez l'enfant sont Mycoplasma pneumoniae ou Chlamydia pneumoniae. La prise en charge des bronchopneumopathies atypiques à ces deux germes reste actuellement floue. La symptomatologie est pauvre, aucun signe clinique spécifique n'a pu être à ce jour identifié. Il semblerait que les infections respiratoires à M. pneumoniae sont associées à des douleurs thoraciques ou à une absence de wheezing même si cela reste à confirmer. Les infections à C. pneumoniae seraient plus souvent associées à des laryngites. Les co-infections virales, bactériennes ou entre les deux germes atypiques, M. pneumoniae et le C. pneumoniae, ne sont pas rares. Une infection par une de ces deux bactéries augmenterait l'incidence de l'asthme. Le diagnostic par PCR semble être la méthode diagnostique la plus spécifique et la plus sensible, autant pour le M. pneumoniae que pour le C. pneumoniae. Cependant, elle ne permet pas de différencier les infections des portages asymptomatiques. Le diagnostic par sérologie peut être utile mais nécessite deux échantillons à quelques semaines d'intervalle. Les macrolides sont la classe d'antibiotique classiquement utilisées dans le traitement des infections à ces deux germes. L'ef ficacité du traitement antibiotique pour le M. pneumoniae est actuellement remis en doute par certaines études. Des résistances au traitement du M. pneumoniae par macrolide sont décrites. En conclusion, il manque encore de littérature scientifique à hauts niveaux de preuve et de concensus clairs dans la prise en charge des suspicions d'infection à M. pneumoniae et C. pneumoniae.

Three cases of atypical pneumonia caused by Chlamydophila psittaci.

Psittacosis is a zoonotic disease caused by Chlamydophila psittaci. The most common presentation is atypical pneumonia. Three cases of pneumonia of varying severity due to psittacosis are described. All patients had a history of avian contact. The diagnosis was confirmed by molecular detection of Chlamydophila psittaci in respiratory specimens. The cases showed good recovery with doxycycline treatment. Increased awareness of psittacosis can shorten diagnostic delay and improve patient outcomes.

Preparation and evaluation of monoclonal antibodies against chlamydial protease-like activity factor to detect Chlamydia pneumoniae antigen in early pediatric pneumonia.

Chlamydia pneumoniae causes diseases in humans, including community-acquired pneumonia, bronchitis, and sinusitis. It is also associated with atherosclerosis, coronary heart disease, and hyperlipidemia. In this study, we investigated novel materials with which to develop a sensitive and specific method to identify early C. pneumoniae infection, to allow more effective clinical treatment and prevention. We prepared novel monoclonal antibodies (mAbs) against a recombinant protein equivalent to the immunodominant region of chlamydial protease-like activity factor (CPAF) from C. pneumoniae. The mAbs specifically reacted with the endogenous CPAF antigen of the C. pneumoniae type strain in immunoblotting and indirect immunofluorescence (IIF) assays, but did not react with C. trachomatis type strains or genital secretions from patients with acute C. trachomatis infection. The mAb with the highest titer was used to develop a new IIF assay and enzyme-linked immunosorbent assay (ELISA) to detect the C. pneumoniae antigen in clinical specimens from child patients suspected of pneumonia. The sensitivity, specificity, and concordance rate of the mAb-based IIF and ELISA tests were compared with those of polymerase chain reaction (PCR). Our results show that these mAbs have excellent specificity and may be used to develop new screening tools for the diagnosis of early pediatric pneumonia.

[Chlamydia trachomaatis DNA in leukocytes of peripheral blood from neonates]. / ADN de Chlamydia trachomatis en leucocitos de sangre periférica de neonatos.

INTRODUCTION: Diagnosis of Chlamydia trachomatis infection in newborns is difficult; however, this diagnosis is performed by cell culture or by detection of IgM antibodies against C. trachomatis. Detection of C. trachomatis DNA in peripheral blood leukocytes using polymer chain reaction (PCR) may be a better tool for the diagnosis of infection by this pathogen. MATERIAL AND METHODS: A total of 44 premature newborns, all weighing less than 2500g, were included in the study. A blood sample and nasopharyngeal lavages were obtained from each newborn. Leukocyte DNA was obtained by phenol-chloroform extraction technique. Detection of C. trachomatis was performed by amplifying the ompA gene using the PCR endpoint. Cell culture tests and the detection of IgM antibodies against C. trachomatis by microimmunofluorescence assay were also performed. RESULTS: Twenty newborns were PCR-positive (45.5%), with this test being significantly associated with the presence of pneumonia (RR=2.28; 95%CI: 1.01 to 5.17; P=.035). The cell culture of nasopharyngeal lavage was positive in only 7 samples and no significant association was observed with any clinical or laboratory data. The titer of IgM antibodies against C. trachomatis associated with PCR-positive was 1:32 (RR=2.74; 95%CI: 1.21 to 6.23; P=.008), however this titer was not associated with the presence of pneumonia. CONCLUSION: DNA detection in peripheral blood leukocytes could be useful for diagnosis of C. trachomatis infection.

[Recommendations for the use of diagnostic testing in low respiratory infections in children older than three months]. / Recommandations sur l'utilisation des nouveaux outils diagnostiques étiologiques des infections respiratoires basses de l'enfant de plus de trois mois.

Recommendations for the use of diagnostic testing in low respiratory infection in children older than 3 months were produced by the Groupe de Recherche sur les Avancées en Pneumo-Pédiatrie (GRAPP) under the auspices of the French Paediatric Pulmonology and Allergology Society (SP(2)A). The Haute Autorité de santé (HAS) methodology, based on formalized consensus, was used. A first panel of experts analyzed the English and French literature to provide a second panel of experts with recommendations to validate. Only the recommendations are presented here, but the full text is available on the SP(2)A website.

[Late debut of neonatal pneumonia caused by Chlamydia trachomatis]. / Sen debut af neonatal pneumoni forårsaget af Chlamydia trachomatis.

A newborn colonized with Chlamydia trachomatis will often show symptoms of conjunctivitis and/or pneumonia. We report a case of interstitial pneumonia caused by C. trachomatis in a 2-month-old boy admitted with RSV. We point to the importance of C. trachomatis in the differential diagnostics of an infant with respiratory symptoms even in the presence of additional infectious agents.