Molecular detection of Chlamydia psittaci in birds: a systematic review

RESEARCH HIGHLIGHTS

Hierarchical molecular testing is recommended for the detection of avian C. psittaci.Key molecular tests for surveillance were conventional PCR and quantitative PCR.The most used genomic target to detect C. psittaci in birds was the ompA gene.

Chlamydia in farms located in the Argentine-Brazilian-Paraguay tri-border

Chlamydias are zoonotic pathogens, broadly present in several bird species and responsible for economic losses in animal production. Our study focused on assessing the prevalence of Chlamydial species posing zoonotic risks in farm animals within the highly biodiverse Argentine, Brazil, and Paraguay tri-border area, characterized by significant human interaction. We surveyed nine farms in an area and nasally swabbed a total of 62 animals, that included cattle, horses and pigs. DNA was extracted and specific PCR was performed to identify and sequenced chlamydial species. We detected Chlamydia spp. in 6.5% (4/62) of the tested animals, with all positive cases found in cattle. None of the cattle showed symptoms of respiratory disease or had been diagnosed with reproductive disorders. Specific nested PCR confirmed two samples belonged to Chlamydia pecorum and two to Chlamydia psittaci. We report for the first time Chlamydia circulation with zoonotic risk in the region. We propose that surveys in birds and wild mammals could give a better understanding to know what Chlamydial species are circulating in the wild interface. The zoonotic potential should be taking into account as farm workers and the surrounding population could be silent carriers or have respiratory diseases being underdiagnosed, and therefore should be considered in the differential diagnoses.

Avian Gastroenterology: Noninfectious and Infectious Disease

A vast range of infectious and noninfectious diseases can affect avian patients. Practitioners should be familiar with common presenting signs of these diseases in order to steer diagnostic testing and treatment.

Clinical Features of 50 Cases of Chlamydia psittaci Pneumonia Identified Through Metagenomic Next-Generation Sequencing

Background

Our objective was to analyze the clinical and imaging features of Chlamydia psittaci pneumonia to enhance its diagnostic accuracy.

Methods

We systematically reviewed the cases of Chlamydia psittaci diagnosed by next-generation sequencing at the Hunan University of Medicine General Hospital between March 2019 and June 2024, summarizing and analyzing their clinical characteristics and imaging features.

Results

A total of 50 cases that met the inclusion criteria were ultimately included in the study analysis. The median age of the patients was 62.96±11.08 years. Notably, 46 patients (92%) had potential exposure to birds or poultry. Forty-six patients (92%) temperature ≥39.0 °C, 37 patients (74%) had cough, 34 patients (68%) had moist rale, and 39 patients (78%) had a relatively slow pulse. Laboratory tests indicated that over 70% of patients exhibited elevated infection markers, accompanied by abnormalities in liver and renal function, electrolyte levels, and cardiac enzymes. Meanwhile, the patient's white blood cell count was normal. Chest CT (Computed Tomography) frequently revealed flaky shadows (94%), thoracic effusions (68%), and thickened pleura (54%). Bronchoscopy revealed significant bronchial mucosal hyperemia, swelling (93.478%), and reduced secretion (56.522%). A total of 44 patients (88%) showed a gradual improvement over 12 days. Forty patients (80%) were treated with doxycycline. Fifty patients were classified into two groups according to whether severe pneumonia occurred after admission. WBC (white blood cell), N% (percentage of neutrophils), NLR (Neutrophil-to-lymphocyte ratio), PLR (platelet/lymphocyte ratio), SII (platelet*Neutrophil/lymphocyte ratio), and PCT (procalcitonin) are indicators that suggest severe cases.

Conclusion

The combination of the following indicators is expected to aid in diagnosis of Chlamydia psittaci pneumonia: opportunities to come into contact with birds or poultry, high fever, relatively slow pulse, and elevated infection indicators accompanied by organ injury. Treatment with doxycycline was effective and resulted in favorable prognosis.

Psittacosis Pneumonia Features, Distinguishing Characteristics, and Outcomes: A Retrospective Study

Purpose

Psittacosis is an often-neglected cause of community acquired pneumonia (CAP). The limited diagnostic methods for psittacosis pneumonia invariably result in an unfavourable prognosis. Consequently, the early detection of psittacosis pneumonia is crucial. This study aimed to analyse the characteristics, clinical features and treatments of the patients to improve early diagnosis and outcomes.

Patients and Methods

We retrospectively analyzed the clinical features and outcomes of 52 cases of psittacosis pneumonia diagnosed with next-generation sequencing (NGS) from January 2022 to August 2024 in a local tertiary hospital in China.

Results

Of the 52 patients, 18 had a clear exposure to poultry or birds. The main clinical manifestations included fever (100%, 52/52), cough (75.0%, 39/52), fatigue (57.7%, 30/352), and dyspnea (36.5%, 19/52). Significant elevations in neutrophil counts (NEUT), C-reactive protein (CRP), alanine aminotransferase (ALT), aspartate aminotransferase (AST), D-dimer, lactate dehydrogenase (LDH), creatine kinase (CK), interleukin-6 (IL-6) and interferon-γ (IFN-γ), as well as reductions in lymphocyte (LY) and albumin (ALB) were observed. The main chest computed tomography (CT) features were consolidated. Eight patients diagnosed with severe CAP (SCAP) exhibited higher NEUT, CRP, procalcitonin (PCT), blood urea nitrogen (BUN), creatinine, D-Dimer and IL-6 levels, as well as lower oxygen index. The interval between the onset of symptoms and diagnosis was 6-34 days. C. psittaci infection was identified by metagenomic NGS (mNGS) or targeted NGS (tNGS) in all cases, and the average length of hospital stay for these patients was 9.4 days. Following the identification of the aetiology, all patients were promptly initiated on tetracycline- or fluoroquinolone-based therapy, with complete recovery observed in all cases.

Conclusion

Patients exposed to poultry should be alert to Chlamydia psittaci pneumonia. The application of NGS has improved the diagnostic accuracy of C. psittaci pneumonia, reduced unnecessary use of antibiotics, and shortened the course of disease. Patients who received tetracycline-based therapy showed a good prognosis.

Investigation of awareness, sanitation, and customer education practices among employees of pet and animal feed stores that sell live animals in the United States

BACKGROUND

Numerous zoonotic disease outbreaks have been associated with companion animals and poultry purchased at pet and animal feed stores. Employees are often the initial source of information for customers purchasing a new pet. Therefore, the objectives of this study were to: (1) investigate awareness, sanitation, and customer education practices related to zoonotic disease risk, and (2) identify predictors of providing customer education among employees of pet and animal feed stores that sell live animals.

METHODS

A survey of pet and animal feed store employees was conducted to evaluate sanitation practices, training, and awareness of zoonotic disease risk. Differences in proportions of categorical variables were assessed using Chi-square tests. Wilcoxon rank-sum and Kruskal-Wallis tests were used to assess for differences in the values of ordinal variables based on the values of categorical variables. A partial proportional odds model was used to identify predictors of providing customer education.

RESULTS

Surveys were completed by 206 respondents from the Southeast, Midwest, Southwest, and Western US, 146 of whom reported that their workplace sold live animals. Handwashing was more frequent among employees whose workplace had handwashing policies related to handling animals and their habitats (p < 0.001). Perceived zoonotic disease risk was higher among those who had received workplace training (p = 0.007). Higher odds of providing customer education related to zoonotic disease risk were associated with serving in a supervisory role (p = 0.005), higher perceived zoonotic disease risk (p = 0.001), and more frequent sanitation practices (handwashing, p = 0.031; surface disinfection, p < 0.001; and glove use, p < 0.001).

CONCLUSIONS

Pet and animal feed stores play an important role in minimizing occupational health hazards for employees and providing education for customers. These retailers should implement clear biosecurity protocols and provide training about zoonotic disease risk associated with handling live animals.

Chlamydia psittaci: A zoonotic pathogen causing avian chlamydiosis and psittacosis

Chlamydia psittaci is an obligate intracellular gram-negative bacterium with a unique biphasic developmental cycle. It is a zoonotic pathogen with a wide range of hosts and can cause avian chlamydiosis in birds and psittacosis in humans. The pathogen is transmitted mainly through horizontal transmission between birds. Cross-species transmission sometimes occurs and human-to-human transmission has recently been confirmed. This review provides an updated overview of C. psittaci from the perspective of both avian chlamydiosis and psittacosis. We include the aspects of genotype, host-pathogen interaction, transmission, epidemiology, detection and diagnosis, clinical manifestation, management, and prevention, aiming to provide a basic understanding of C. psittaci and offer fresh insights focused on zoonosis and cross-species transmission.

Early and rapid diagnosis of Chlamydia psittaci pneumonia by tNGS in six patients: a case series

Background

Psittacosis is a zoonotic infectious disease caused by Chlamydia psittaci (C. psittaci) infection, which can be transmitted by birds, poultry and wild animals. The symptoms and imaging findings of C. psittaci pneumonia are atypical and primarily rely on etiological diagnosis. The incidence of C. psittaci infection has been significantly underestimated because of the low sensitivity and poor timeliness of traditional diagnostic methods. Therefore, early and accurate diagnosis of psittacosis remains a challenge.

Case presentation

A case series with six pneumonia patients who were admitted to our hospital in the period from January 2023 to June 2023 is presented. These patients exhibited acute onset and symptoms, including fever, cough, poor appetite, dry mouth, dizziness, chills, and chest tightness. Despite comprehensive laboratory and radiological examinations, the cause of the pneumonia remained unidentified. Therefore, a sample of bronchoalveolar lavage fluid (BALF) was tested via target next-generation sequencing (tNGS), which revealed a positive result for C. psittaci. Prompt adjustment of the treatment regimens upon identification of the pathogen led to favorable outcomes in all patients.

Conclusion

tNGS is a novel diagnostic technology that enables rapid, accurate and cost-effective detection of C. psittaci pneumonia. Early detection of C. psittaci can improve patient outcomes through timely adjustment of therapies.

Diagnosis and treatment experience of Chlamydia psittaci pneumonia: A multicenter retrospective study in China

BACKGROUND

In recent years, clinical cases of Chlamydia psittaci pneumonia have gradually increased. Chlamydia psittaci pneumonia can quickly progress to severe pneumonia, leading to respiratory failure. Chlamydia psittaci cannot be detected by commonly used detection methods, leading to difficulties in clinical diagnosis and treatment, which may eventually develop into severe Chlamydia psittaci pneumonia. Therefore, we should improve our diagnostic and treatment capabilities for this disease.

METHODS

This article retrospectively studied 61 cases of pneumonia from 12 different provinces in China, and classified them into severe pneumonia and non-severe pneumonia. Divided into two groups, with 23 cases of severe pneumonia and 38 cases of non-severe pneumonia. We compared the two groups in terms of imaging, laboratory testing, treatment, prognosis, etc., hoping to provide better explanations and help clinical physicians better diagnose the disease.

RESULTS

There is no difference in age, gender, contact history, smoking history, or basic disease between severe and non-severe Chlamydia psittaci pneumonia. The most prominent symptom is fever, with a median body temperature of 39.7 ℃, and other symptoms similar to common respiratory infections. White blood cells and neutrophils may not show significant elevation, but C-reactive protein (CRP) and procalcitonin (PCT) will both show significant elevation, often accompanied by a decrease in arterial oxygen pressure. Some patients may experience liver and kidney dysfunction, but there is no statistically significant difference between the two groups. Doxycycline remains the preferred drug for severe Chlamydia psittaci pneumonia. The imaging mainly shows consolidation and bronchial inflation sign, and may also present with pleural effusion.

CONCLUSIONS

The imaging of Chlamydia psittaci pneumonia usually shows consolidation with bronchial inflation sign, which can also be manifested as ground glass changes or solid masses. Atypical images are prone to misdiagnosis in the early stages. There are some differences in laboratory examination and imaging between severe pneumonia and non-severe pneumonia, which can help identify severe patients in the early stage. Metagenomic next-generation sequencing (mNGS) played an important role in the diagnosis of all cases in this article. Timely treatment has a good prognosis for the disease, and imaging lesions can be completely absorbed.

What are the priority welfare issues facing parrots in captivity? A modified Delphi approach to establish expert consensus

Parrots (Psittaciformes) are widely kept in captivity, yet their welfare is under-researched in comparison to other captive species. This study aimed to determine key welfare issues affecting parrots through a modified Delphi approach. Twenty-eight welfare issues were first compiled via a preliminary literature review. Parrot welfare experts and sector professionals (n = 26) were then recruited to participate in an online survey to rank the identified welfare issues on a six-point scale according to severity, duration and prevalence of each issue. Participants could provide commentary on their ranking and propose additional welfare issues of concern. Items with a mean score of 4 or above progressed to a second survey, where participants (n = 14) indicated whether they agreed or disagreed with the current ranking of the welfare issue. Finally, two online workshops were held, where participants (n = 7) discussed the rankings from the second survey and sought to establish a consensus on the top ten welfare issues in each category and overall. Six of the seven final participants agreed with the final rankings, achieving a consensus rate of 86%. The top welfare issues overall were lack of owner knowledge and support; social isolation; housing; environmental opportunity to express behaviours; nutrition; development of normal behaviour; lack of a 'life plan' for birds; abnormal behaviours; lack of parrot-specific veterinary training; and insufficient application and enforcement of legislation. It is hoped that identification and recognition of these priority areas will be useful in directing future efforts in research, owner and veterinary education, and policy initiatives to improve parrot welfare.

Hearing loss as the first symptom of pneumonia caused by Chlamydia psittaci: a case report and literature review

BACKGROUND

The typical clinical symptoms of psittacosis pneumonia include fever, dry cough, and chills. Sudden sensorineural hearing loss is a relatively uncommon condition in pneumonia caused by Chlamydia psittaci. In this study, we reported a rare case of Chlamydia psittaci pneumonia presented as hearing loss.

CASE PRESENTATION

A 65-year-old man presented to our hospital with sudden hearing loss, cough with sputum, and fever for the last three days. Chest computed tomography revealed inflammation of the left lung and poor response to broad-spectrum antibiotics. The metagenomic next-generation sequencing (mNGS) of bronchoalveolar lavage fluid identified the sequence of Chlamydia psittaci. Subsequently, antibiotic treatment was adjusted to doxycycline hydrochloride and moxifloxacin, resulting in significant improvement in both hearing loss and lung infection.

CONCLUSIONS

Sudden sensorineural hearing loss as an extrapulmonary feature of Chlamydia psittaci pneumonia is extremely rare. Although the exact mechanism remains unclear, this case report described a patient with sudden bilateral sensorineural hearing loss as a presenting feature of Chlamydia psittaci pneumonia, illustrating the importance of the extrapulmonary features of atypical pneumonia. The mNGS test could provide early diagnosis. Many patients had a good prognosis with prompt and effective treatment.

First Overview of Zoological Medicine on Iberian Countries

The role of veterinary doctors, particularly those dedicated to Zoological Medicine, is becoming increasingly relevant and essential within the One Health framework. Educational and employment opportunities in this field vary widely across Europe, prompting us to characterise the sector in Portugal and Spain. A survey was conducted, resulting in 169 valid responses from veterinarians. Respondents were characterised based on gender, age, work environment, the highest level of education, additional training, whether they attended zoological medicine classes at university and their perception of the adequacy of that training. Further factors included years of experience, the percentage of their work involving zoological medicine, sectors they work in, the types of animals they treat, their confidence in treating these animals, sources of information they use, and membership in relevant professional associations. Relationships between these variables were examined. The results describe Iberian professionals working with non-traditional pets, wildlife, and zoo animals. Notably, only half of these professionals had taken zoological medicine classes at university; among those, the majority felt they inadequately prepared them for their work. Given the findings, enhancing the training and resources available to these professionals is crucial to prepare them for their roles better.

The therapeutic efficacy of neem (Azadirecta indica) leaf extract against coinfection with Chlamydophila psittaci and low pathogenic avian influenza virus H9N2 in broiler chickens

Avian chlamydiosis is a serious avian infection that carries a significant zoonotic danger to the poultry industry. The respiratory co-infections caused by the low pathogenic avian influenza virus H9N2 (LPAIV H9N2) also cause significant financial losses in the poultry industry. The purpose of this study was to examine the pathogenicity of Chlamydophila psittaci, and LPAIV H9N2 individually and in combination in broiler chickens, as well as to determine whether or not aqueous neem (Azadirachta indica) leaf extract is effective against infections caused by these pathogens. Therefore, 120 broiler cobb chicks were equally divided into 4 groups (30 birds each) with triplicates with 10 birds. Broilers in group 1 (G1) were infected with only C. psittaci, broilers in group 2 (G2) were infected with only LPAIV H9N2, broilers in group 3 (G3) were infected with C. psittaci and LPAIV H9N2, and broilers in group 4 (G4) remained not challenged and non-treated with any therapeutic or preventive treatment (negative control). At 21 d postinfection (dpi), birds in G1, G2, and G3 were divided into 3 subgroups of 10 birds each: subgroup (A) remained infected and untreated (positive control), subgroup (B) infected and received oxytetracycline for 5 consecutive d, and subgroup (C) infected and received 8% aqueous neem leaf extract for 5 consecutive d. The multiplication of C. psittaci in birds in G1, in various tissues was evaluated using Giemsa staining and the data showed that multiplication was much higher in the lung, spleen, and liver from 6 h to 21 dpi, but low in the heart from 8 to 21 dpi. During simultaneous co-infection in G3, the birds developed significant clinical symptoms and postmortem lesions (PM). Quantitative real-time polymerase chain reaction (qRT-PCR) was used to detect viral shedding from oropharyngeal and cloacal swabs between 2 dpi and 8 dpi, with cycle threshold (CT) values ranging from 22 to 24. In contrast, bacterial shedding began 6 h after infection and continued until 21 dpi, with CT values ranging from 23 to 26. Administration of an aqueous neem leaf extract at an 8% concentration (Group C) resulted in a numerical rise in average body weight across all treatment groups in the third and fourth week, as well as a reduction in LPAIV H9N2 and C. psittaci replication in the respiratory and gut of treated birds compared to those treated with oxytetracycline (Group B). Overall, respiratory co-infections pose a considerable risk to the poultry business, which is a big threat. To control C. psittaci and LPAIV H9N2 in broiler chickens, oral supplementation of 8% aqueous neem leaf extract is recommended. This treatment improves the birds' performance, as evidenced by an increase in their average body weight. In addition, the application of 8% aqueous neem leaf extract lowers C. psittaci replication within tissues and diminishes LPAIV H9N2 shedding.

Clinical Features and a Prediction Model for Early Prediction of Composite Outcome in Chlamydia psittaci Pneumonia: A Multi-Centre Retrospective Study in China

Introduction

C. psittaci pneumonia has atypical clinical manifestations and is often ignored by clinicians. This study analyzed the clinical characteristics, explored the risk factors for composite outcome and established a prediction model for early prediction of composite outcome among C. psittaci pneumonia patients.

Methods

A multicenter, retrospective, observational cohort study was conducted in ten Chinese tertiary hospitals. Patients diagnosed with C. psittaci pneumonia were included, and their clinical data were collected and analyzed. The composite outcome of C. psittaci pneumonia included death during hospitalization, ICU admission, and mechanical ventilation. Univariate and multivariable logistic regression analyses were conducted to determine the significant variables. A ten-fold cross-validation was performed to internally validate the model. The model performance was evaluated using various methods, including receiver operating characteristics (ROC), C-index, sensitivity, specificity, positive/negative predictive value (PPV/NPV), decision curve analysis (DCA), and clinical impact curve analysis (CICA).

Results

In total, 83 patients comprised training cohorts and 36 patients comprised validation cohorts. CURB-65 was used to establish predictive Model 1. Multivariate logistic regression analysis identified three independent prognostic factors, including serum albumin, CURB-65, and white blood cells. These factors were employed to construct model 2. Model 2 had acceptable discrimination (AUC of 0.898 and 0.825 for the training and validation sets, respectively) and robust internal validity. The specificity, sensitivity, NPV, and PPV for predicting composite outcome in the nomogram model were 91.7%, 84.5%, 50.0%, and 98.4% in the training sets, and 100.0%, 64.7%, 14.2%, and 100.0% in the validation sets. DCA and CICA showed that the nomogram model was clinically practical.

Conclusion

This study constructs a refined nomogram model for predicting the composite outcome in C. psittaci pneumonia patients. This nomogram model enables early and accurate C. psittaci pneumonia patients' evaluation, which may improve clinical outcomes.

Prevalence and genotypes of Chlamydia psittaci in pet birds of Hong Kong

Psittacosis, or parrot fever, is a zoonotic disease caused by Chlamydia species associated with birds. One of the causative agents of the disease is Chlamydia psittaci, which is commonly carried by psittacine and other bird species, can be highly pathogenic and virulent to humans. In Hong Kong, a city with high population density, psittacosis is a notifiable disease with over 60% of cases in the last decade resulting in hospitalization. However, the sources of transmission of C. psittaci and its prevalence in pet birds in Hong Kong are currently unknown. To evaluate the risks of psittacosis transmission through pet birds, we tested the presence of C. psittaci and determined its genotypes in samples obtained from 516 captive birds from households, pet shops, and a veterinary hospital in Hong Kong. Results revealed that five samples (0.97%), collected from budgerigars and cockatiels, were C. psittaci-positive, while four (80%) of them were obtained from pet shops. Our phylogenetic analysis revealed that all identified strains belonged to Genotype A and showed high similarity to other sequences of this genotype obtained from various geographical locations and host species, including mammals. Our findings provide evidence for the presence of Chlamydia psittaci and shed light on its sources in captive birds in Hong Kong. They highlight the potential zoonotic risks associated with this pathogen, which can affect both humans and wild birds.

A Case Study of Severe Pneumonia Caused by mixed Infection of Chlamydia Abortus and Influenza a in a Female Patient

Background

Chlamydia abortus is a zoonotic pathogen that causes miscarriage, stillbirth, and sepsis of pregnancy in pregnant women when it infects humans. However, it rarely causes pneumonia in humans.

Case Presentation

This case reports a case of severe pneumonia characterized by high fever and cough, and the disease rapidly progressed to dyspnea. The patient was treated with moxifloxacin and doxycycline. Chlamydia abortus was detected in bronchoscopy examination and bronchoalveolar lavage fluid (BALF) through metagenomic next-generation sequencing (mNGS)-DNA. A weak positive for influenza A (H1N1) antigen was also found in the throat swab tested. Subsequently, we added mabaloxavir and replaced doxycycline with an intravenous infusion of omadacycline. After effective treatment, the patient developed a urinary tract infection, and the treatment plan was adjusted to meropenem combined with omadacycline. The patient's condition improved, and she was discharged on the 14th day of admission.

Conclusion

This is the first report of cases of non-pregnant female patients with Chlamydia abortus infection pneumonia. Consequently, infections with Chlamydia abortus can result in severe respiratory distress, disturbance of water and electrolyte balance, and abnormal liver function, which requires timely diagnosis and correct use of antibiotics by clinicians. Consequently, the mixed infection of H1N1 and Chlamydia abortus aggravated the complexity of the condition and treatment. Combining tetracycline and quinolone is effective for treating severe pneumonia with Chlamydia abortus infection.

Chlamydia psittaci infected cell studies by 4Pi Raman and atomic force microscopy

Chlamydia psittaci is an avian bacterial pathogen that can cause atypical pneumonia in humans via zoonotic transmission. It is a Gram-negative intracellular bacterium that proliferates inside membrane bound inclusions in the cytoplasm of living eukaryotic cells. The study of such cells with C. psittaci inside without destroying them poses a significant challenge. We demonstrated in this work the utility of a combined multitool approach to analyze such complex samples. Atomic force microscopy was applied to obtain high-resolution images of the surface of infected cells upon entrance of bacteria. Atomic force microscopy scans revealed the morphological changes of the cell membrane of Chlamydia infected cells such as changes in roughness of cell membrane and the presence of micro vesicles. 4Pi Raman microscopy was used to image and probe the molecular composition of intracellular bacteria inside intact cells. Information about the structure of the inclusion produced by C. psittaci was obtained and it was found to have a similar molecular fingerprint as that of an intracellular lipid droplet but with less proteins and unsaturated lipids. The presented approach demonstrates complementarity of various microscopy-based approaches and might be useful for characterization of intracellular bacteria.

Compare Clinical Characteristics of Psittacosis Pneumonia in 35 Patients and of Non Psittacosis Bacterial Pneumonia in 46 Patients

Background

We aimed to describe the difference between Chlamydia psittaci pneumonia group and non C. psittaci bacterial pneumonia group in community acquired pneumonia in this single-center clinical study.

Methods

We collected the data of 35 patients with C. psittaci pneumonia cases and 46 patients with non C. psittaci bacterial pneumonia cases diagnosed with metagenomic next-generation sequencing assays from February 2019 to December 2021 in Huaihua First People's Hospital in China.

Results

In the C. psittaci pneumonia group, 35 patients (100%) had a chance of exposure to poultry or birds, and their body temperature was greater than or equal to 39.0°C. The other common symptoms were a slow pulse (68.6%), cough (65.7%), expectoration (54.3%), chills (51.4%) and a shortness of breath (37.1%). Laboratory tests showed that >90% of the cases had markedly elevated infection indicators, and 97.1% of the cases had markedly declined calcium. The most common imaging finding was patchy shadows (94.3%), pleural effusion (68.6%), bilateral in 54.3% (n = 19) and unilateral in 45.7% (n = 16) participants, and 51.4% (n = 18) of cases met the criteria for severe pneumonia. In the non C. psittaci bacterial pneumonia group, 18 patients (39.1%) had a chance of exposure to poultry or birds, and 11 patients (23.9%) body temperature was greater than or equal to 39.0°C. Laboratory tests showed that >67% of cases had a mildly elevated infection indicators, and mildly declined serum albumin.

Conclusion

The following characteristics are more likely to help distinguish C. psittaci pneumonia from non C. psittaci bacterial pneumonia. Including had a chance of exposure to poultry or birds, high fever, exhibit chills, expectoration, relatively slow pulse, and progress into severe pneumonia. Percentage of neutrophils, C-reactive protein, procalcitonin, lactate dehydrogenase, and myoglobin levels are higher. Blood calcium and corrected calcium are lower. Chest CT showed pleural effusion, pericardial effusion, and mediastinal lymphadenopathy.

Outbreak of Chlamydia psittaci Infection in a Commercial Psittacine Breeding Aviary in Argentina

Chlamydiosis, caused by Chlamydia psittaci is a bacterial infection found in at least 465 species of birds worldwide. It is highly contagious among birds and can spread to humans. In birds, the disease can manifest itself in acute, subacute, and chronic forms with signs including anorexia, diarrhea, lethargy, weight loss, or, occasionally, mucopurulent or serous oculonasal discharge. This article describes an outbreak of chlamydiosis that occurred in a commercial psittacine breeding aviary in 2021 in Buenos Aires province, Argentina. In total, 16 juvenile blue-fronted parrots, more than 60 blue-fronted parrot chicks, and 2 adult macaws died during the outbreak. In all cases, clinical signs were weight loss, diarrhea, yellowish green excrement, and respiratory distress. The necropsy of four juvenile blue-fronted parrots, two blue-fronted parrot chicks, and two adult macaws revealed cachexia, hepatomegaly, splenomegaly, splenic petechial hemorrhages, ascites, pulmonary edema, and hydropericardium. Histologically, multifocal lymphoplasmacytic and heterophilic airsaculitis, multifocal lymphoplasmacytic and necrotizing hepatitis with intracytoplasmic elementary bodies, multifocal necro-heterophilic hepatitis, multifocal lymphoplasmacytic nephritis, and diffuse heterophilic pneumonia were found. A presumptive diagnosis was established based on gross and microscopic lesions, and it was confirmed using immunohistochemistry and polymerase chain reactions. The sequencing and phylogenetic analysis of the ompA gene revealed genotype A and B of Chlamydia psittaci.

Serum C-reactive protein to albumin ratio as a potential risk indicator of pneumonia caused by Chlamydia psittaci: a multicenter retrospective study

Introduction

The aim of the study was to describe psittacosis pneumonia and to assess the predictive value of the C-reactive protein/albumin ratio in psittacosis pneumonia for severity.

Methods

Data on psittacosis pneumonia cases diagnosed using metagenomic sequencing were collected from three hospitals in Shanghai, China from Oct. 2019 to Oct. 2022. Serum levels of C-reactive protein and albumin were measured and the C-reactive protein to albumin ratio (CAR) was calculated. Spearman's correlation analysis, ordered logistic regression analysis, and receiver operating characteristic curve analysis were conducted to examine the correlation and predictive ability of the three indicators on the severity of the disease.

Results

A total of 27 patients with psittacosis pneumonia were enrolled, with an average age of 62 years and 70.4% being male. 44.4% of patients had a clear history of contact with poultry or birds. The predominant symptom was fever (100%). Patients treated in the respiratory intensive care unit (RICU) had a higher likelihood of experiencing wheezing (88.9% versus 33.3%, P=0.013) and chest tightness (88.9% vs. 33.3%, P=0.013) than those in the general ward (Non-RICU). The proportion of patients with pleural effusion was significantly higher in the RICU compared to the Non-RICU (88.9% vs. 38.9%, P=0.019). The RICU group had a significantly higher CAR than the Non-RICU group (9.41 vs. 4.05, P=0.017). This result was accompanied by higher intubation and ventilator support (33.3% vs. 0.0%, P=0.029), higher PCT and CRP levels and lower albumin and PaCO2 levels in the RICU than in the Non-RICU. Logistic regression analysis indicated that CAR (OR 1.49; 95% CI 1.07-2.06, P=0.017) was risk factor for prolonged hospitalization (> 14 days).

Discussion

Elevated serum CAR levels were found to be associated with a greater risk of severe psittacosis pneumonia. Consequently, it may serve as an uncomplicated and useful diagnostic tool for clinicians to promptly and precisely ascertain the severity of psittacosis pneumonia, ultimately aiding them in devising the most optimal therapeutic plan.

Complete genome sequence of Chlamydia psittaci NRM_5 strain isolated from the fecal samples of a wild Indian ring-necked parakeet (Psittacula krameri manillensis) in Japan

We report here the whole-genome sequence of the Chlamydia psittaci NRM_5 strain isolated from the fecal samples of wild Indian ring-necked parakeet (Psittacula krameri manillensis) in Japan. The sequence type is ST35, which is known to be associated with pigeons and doves, indicating the potential for transmission among bird species.

Examining Intercage Transmission of Chlamydia muridarum : Impact of Barrier Husbandry and Cage Sanitization

Chlamydia muridarum (Cm) has reemerged as a prevalent bacterial contaminant of academic research mouse colonies. A study was conducted to assess the effectiveness of husbandry and cage sanitization methods in preventing intercage transmission of Cm. To assess intercage transmission during cage change, a cage housing 2 Cm-free Swiss Webster (Tac:SW; SW) sentinel mice was placed randomly on each of 12 individually ventilated cage racks, housing cages with Cm-shedding mice, located in 1 of 2 animal holding rooms. Husbandry staff blinded to the study cages, changed all cages in the animal holding rooms weekly using microisolator cage technique. PCR testing performed 180 days post-placement confirmed all mice remained negative for Cm. To assess the effectiveness of cage sanitization to eliminate Cm, we investigated transmission of Cm to a naïve Cm-free SW and NOD.Cg- Prkdc scid Il2rg tm1Wjl /SzJ (NSG) mouse co-housed for 7 days (repeated weekly for 4 weeks) in cages assigned to 1 of 3 groups (n=10 pairs of mice/group). Cages that previously housed 2 Cm-shedding BALB/c mice were either washed in a tunnel washer (82.2°C [180°F] final rinse for an average of 16 seconds per run; n=10) with and without post-washing autoclaving (121°C for 20 minutes; n=10), or were untreated (bedding change only; n=10). Pre- and post-sanitization swabs of each cage were assayed for Cm by PCR. All pre-treatment swabs tested positive, while post-treatment swabs from all cages (excluding bedding change) tested negative. All SW and NSG mice, irrespective of group, remained negative for Cm as determined by PCR. These findings suggest that infectious Cm does not persist in untreated cages nor after mechanical washing with and without autoclaving. Collectively, these findings suggest that neither our husbandry protocols nor inadequate cage sanitization methods likely contributed to the observed prevalence of Cm in contemporary research mouse colonies.

Type B3 thymoma complicated with Chlamydia psittaci pneumonia with rare features: A case report

The case of a patient with type B3 thymomacomorbid with Chlamydia psittaci (C. psittaci) pneumonia exhibiting rare features is presented in the current report. The patient was admitted at the Second Affiliated Hospital of Jiaxing University (Jiaxing, China) with a history of direct contact with poultry. Clinical manifestations included fever, shivers, cough, fatigue and poor appetite. Chest computed tomography (CT) indicated right lung pneumonia, while metagenomics next-generation sequencing using bronchoalveolar lavage fluid confirmed infection with C. psittaci. Additionally, positron emission tomography-CT suggested the presence of thymoma. After surgery and treatment with doxycycline and imipenem cilastatin, the patient was discharged showing signs of improvement.

Pneumonia Caused by Chlamydia psittaci and SARS-CoV-2 Coinfection Diagnosed Using Metagenomic Next-Generation Sequencing: A Case Report

We report a case of pneumonia caused by coinfection with Chlamydia psittaci and the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron XBB.1 variant, confirmed using metagenomic next-generation sequencing (mNGS) and quantitative polymerase chain reaction (qPCR). C. psittaci and SARS-CoV-2 were detected in bronchoalveolar lavage fluid using mNGS. Additionally, mNGS detected C. psittaci in blood and nasopharyngeal specimens and was more sensitive than qPCR. The patient recovered after treatment with moxifloxacin. This report highlights the use of coinfections of C. psittaci and SARS-CoV-2, as mNGS has already been recognized to be a diagnostic tool for identifying coinfections.

Case Report: Pneumonia Caused by Chlamydia Psittaci and Cryptococcus Co-Infection

This study presents a rare case of pneumonia caused by a co-infection of Chlamydia psittaci and Cryptococcus, confirmed by metagenomic next-generation sequencing (mNGS). The patient, who had underlying chronic hepatitis B, had adopted a stray pigeon before the onset of the disease. The primary symptoms were fever, and a productive cough. The patient recovered following treatment with moxifloxacin and itraconazole. C. psittaci and Cryptococcus infections may both have been transmitted from the stray pigeon. This report highlights the potential for infections caused by multiple zoonotic pathogens and the value of mNGS for making the diagnosis of these infections.

Clinical Characteristics of Chlamydia psittaci Infection Diagnosed by Metagenomic Next-Generation Sequencing: A Retrospective Multi-Center Study in Fujian, China

Objective

This study aimed to describe and compare the epidemiological, demographic, clinical, laboratory and radiological characteristics as well as the complications, treatments, and outcomes of these patients.

Methods

We retrospectively investigated clinical data of patients with C. psittaci infection (psittacosis) in eight Grade IIIA hospitals of Fujian. Metagenomic next-generation sequencing (mNGS) was used identify C. psittaci in clinical samples of all included patients.

Results

A total of 74 patients (39 severe/35 non-severe) was diagnosed with psittacosis, 25 (33.8%) of whom had history of poultry exposure. Common symptoms included high fever (98% [37/74]), fatigue (52.7% [39/74]), and dyspnea (51.4% [38/74]). Common manifestations in imaging included consolidation (89.2%), pleural effusion (77.0%), and air bronchogram (66.2%). Common complications included acute respiratory distress syndrome (55.4% [41/74]), type I respiratory failure (52.7% [39/74]), acute liver injury (41.9% [31/74]), and secondary infection (27.0% [20/74]). The in-hospital mortality rate was 8.11% (6/74).

Conclusion

C. psittaci infection is represents an underestimated cause of CAP. For SCAP patients with poultry and bird contact history, specimens were encouraged to be sended for mNGS test in time. C. psittaci infection can lead to severe, multiple system involvement, and several complications. mNGS facilitate timely diagnosis of C. psittaci infection.

Bacterial communities along parrot digestive and respiratory tracts: the effects of sample type, species and time

Digestive and respiratory tracts are inhabited by rich bacterial communities that can vary between their different segments. In comparison with other bird taxa with developed caeca, parrots that lack caeca have relatively lower variability in intestinal morphology. Here, based on 16S rRNA metabarcoding, we describe variation in microbiota across different parts of parrot digestive and respiratory tracts both at interspecies and intraspecies levels. In domesticated budgerigar (Melopsittacus undulatus), we describe the bacterial variation across eight selected sections of respiratory and digestive tracts, and three non-destructively collected sample types (faeces, and cloacal and oral swabs). Our results show important microbiota divergence between the upper and lower digestive tract, but similarities between respiratory tract and crop, and also between different intestinal segments. Faecal samples appear to provide a better proxy for intestinal microbiota composition than the cloacal swabs. Oral swabs had a similar bacterial composition as the crop and trachea. For a subset of tissues, we confirmed the same pattern also in six different parrot species. Finally, using the faeces and oral swabs in budgerigars, we revealed high oral, but low faecal microbiota stability during a 3-week period mimicking pre-experiment acclimation. Our findings provide a basis essential for microbiota-related experimental planning and result generalisation in non-poultry birds.

Pet safety guidelines for pediatric transplant recipients

Approximately 70% (90.5 million) of United States (US) households own at least one pet. Dogs are the most common, making up about 38% of all household pets, followed by cats, which make up 25%. Other pets such as fish, birds, reptiles, and small animals such as hamsters, gerbils, and rabbits are less common household members. Pets are often considered a part of the family and there are significant medical and psychosocial benefits to pet ownership; however, the possibility of disease transmission exists related to the type of animal and infectious organism, and specific human risk factors. Immunocompromised individuals may be at increased risk of serious illness from zoonotic infections. During the transplant evaluation and routinely posttransplant, the multidisciplinary team should inquire about pet ownership and animal exposures to guide on potential risks. This review discusses the most common diseases seen in various household pets including dogs, cats, birds, fish, and some farm animals. We will also present guidelines for pet safety and include strategies to decrease the risk of infection while supporting the benefits of pet ownership after transplant.

Belgian Cross-Sectional Epidemiological Study on Zoonotic Avian Chlamydia spp. in Chickens

Chlamydia psittaci, Chlamydia gallinacea, and Chlamydia abortus are the most common Chlamydia spp. in chickens and have a confirmed or suggested zoonotic potential. No recent data are available on their prevalence and impact in the Belgian chicken industry or in the recreational chicken branch. Therefore, a cross-sectional epidemiological study was executed where samples were collected from both factory-farmed and backyard chickens. More specifically, pharyngeal chicken swabs were obtained from 20 chicken farms, 5 chicken abattoirs, and 38 different backyard locations and were analyzed using species-specific Polymerase Chain Reactions (PCRs) for the presence of the three avian Chlamydia spp. To investigate their zoonotic potential, samples were simultaneously collected from 54 backyard chicken caretakes and 37 professional chicken caretakers or abattoir employees and analyzed using species-specific PCRs as well. This study confirmed the presence of DNA of all three Chlamydia species in both the chicken industry and backyard settings. Chlamydia psittaci was the most prevalent in the industry chickens (11.0%), whereas Chlamydia gallinacea was the dominant species in the backyard chickens (14.5%). Chlamydia abortus infections were more common in the commercial chickens (9.0%) compared to the backyard chickens (2.6%). The DNA of all three species was also detected in humans (3.9% Chlamydia psittaci, 2.9% Chlamydia gallinacea, and 1.0% Chlamydia abortus).

Omadacycline for the treatment of severe pneumonia caused by Chlamydia psittaci complicated with acute respiratory distress syndrome during the COVID-19 pandemic

Introduction

Chlamydia psittaci infection in humans is a rare cause that mainly present as community-acquired pneumonia. Severe Chlamydia psittaci pneumonia can lead to acute respiratory distress syndrome (ARDS), septic shock, or multiple organ dysfunction with a mortality rate of 15%-20% before accurate diagnosis and targeted treatment. Metagenomic next-generation sequencing (mNGS) has an advantage in achieving early diagnosis. In the study, omadacycline implementation was described to provide a better understanding of effectiveness in severe psittacosis pneumonia with ARDS.

Methods

Sixteen patients with severe psittacosis pneumonia with ARDS were selected between September 2021 and October 2022. They were diagnosed using mNGS and treated with omadacycline. Retrospective analysis of clinical manifestations, laboratory data, disease progression, diagnostic tool, treatment, and prognosis was summarized.

Results

Common symptoms included fever, dyspnea, and cough. All patients developed ARDS, accompanied by septic shock (43.7%) and pulmonary embolism (43.7%). Laboratory data showed normal leucocytes, increased creatine kinase isoenzyme, and decreased albumin with liver dysfunction in most patients. All patients had increased neutrophils, C-reactive protein, procalcitonin, and D-dimer with decreased lymphocytes. Airspace consolidation, ground glass opacity, and pleural effusion were found on chest CT. mNGS results were obtained in 24-48 h to identify the diagnosis of Chlamydia psittacosis. All patients received mechanical ventilation with omadacycline treatment. Fourteen patients experienced complete recovery, while the other two patients died from multidrug-resistant bacterial infection and renal failure.

Conclusion

mNGS has a significant value in the diagnosis of Chlamydia psittaci infection. Timely treatment of omadacycline can improve prognosis and provide a promising new option for the treatment of severe Chlamydia psittaci pneumonia with ARDS.

Venous-arterial extracorporeal membrane oxygenation for psittacosis pneumonia complicated with cardiogenic shock: case report and literature review

INTRODUCTION

Dilated cardiomyopathy (DCM) is characterized by the enlargement of the left ventricle or biventricular, accompanied by myocardial systolic dysfunction. Chlamydia psittacosis (CP) is a zoonotic pathogen, which can cause severe pneumonia, respiratory failure, and acute organ dysfunction. The deterioration of DCM caused by CP infection is extremely rare, and few cases of successful management were reported.

CASE PRESENTATION

We reported a 67-year-old male patient with DCM and chronic heart failure. Who was admitted to ICU with severe pneumonia, acute hypoxemic respiratory failure, acute decompensated heart failure, arrhythmia, and cardiogenic shock. Mechanical ventilation (MV) and venous-arterial extracorporeal membrane oxygenation (VA-ECMO) were established for respiratory and circulatory support. Broncho alveolar lavage fluid(BALF)was collected for culture and metagenomics next-generation sequencing (mNGS) test. Repeated mNGS tests indicated the high possibility of CP pneumonia, thereafter, moxifloxacin and doxycycline were prescribed. After targeted antibiotics and organ support treatment, pneumonia, respiratory and circulatory failure were gradually resolved, patient was successfully weaned from MV and VA-ECMO. Finally, the patient was recovered and discharged alive.

CONCLUSIONS

Severe respiratory and circulatory failure caused by CP infection in DCM patients is a rare life-threatening clinical condition. Early accurate diagnosis, targeted antibiotic therapy, coupled with extracorporeal life support posed positive impact on the patient's disease course and outcome.

Diagnosis and Surgical Treatment of a Renal Cyst Causing Unilateral Lameness in a Golden Eagle (Aquila chrysaetos)

This report describes the diagnosis and treatment of a benign renal cyst in an adult, female golden eagle (Aquila chrysaetos) presented for unilateral leg lameness. A cyst at the cranial division of the left kidney was diagnosed by computed tomography and was suspected of compressing the lumbosacral nerve plexus, resulting in limb lameness. The renal cyst was incompletely excised because the cyst wall was closely adhered to the kidney parenchyma and local blood supply. Fluid analysis and surgical biopsy of the cyst and left kidney confirmed the diagnosis of a benign renal cyst. No evidence of an infectious, inflammatory, or neoplastic etiology was noted. Postoperatively, the eagle's lameness resolved and the bird was ultimately released following recovery. During treatment for the renal cyst, the eagle was concurrently found to have increased serum titers on elementary body agglutination for Chlamydia psittaci and a positive titer for Aspergillus species antibody testing. The bird was administered doxycycline, azithromycin, and voriconazole for treatment of these potential pathogens prior to release. Unfortunately, the eagle was found dead 86 days postrelease due to an unknown cause. To the authors' knowledge, this is the first report of a golden eagle with a benign solitary renal cyst causing unilateral lameness secondary to nerve compression that was resolved with surgical excision.

Chlamydia psittaci Pneumonia-Induced Pulmonary Thrombosis: A Case Report

Chlamydia psittaci pneumonia frequently leads to various extrapulmonary complications; however, reports of C. psittaci-pneumonia complicated by pulmonary thrombosis are uncommon. We report a case of severe C. psittaci pneumonia in a patient with a history of poultry contact and clinical manifestations including hyperpyrexia, dyspnea, and respiratory failure, which necessitated tracheal intubation for assisted ventilation. C. psittaci in bronchoalveolar lavage fluid was detected with metagenomic next-generation sequencing. Following targeted antibiotic therapy, the fever subsided, although dyspnea persisted without significant improvement, and chest pain developed. Compared to previous measurements, the D-dimer level increased, and CT pulmonary angiography revealed thromboses in the pulmonary artery trunk and left pulmonary artery. The symptoms improved after anticoagulant treatment, and the patient was discharged subsequently. This study suggests that C. psittaci infection may be associated with the formation of pulmonary thrombosis. Additional clinical data are required to support this inference. Following targeted antibiotic therapy, if persistent dyspnea, chest pain, and increased D-dimer level are present, pulmonary thrombosis should be considered, and pulmonary artery angiography can confirm the diagnosis.

Clinical features of psittacosis in 46 Chinese patients

BACKGROUND

Psittacosis is a relatively uncommon cause of community-acquired pneumonia, often leading to diagnostic difficulty.

METHODS

A retrospective study was conducted on the clinical features of psittacosis patients in China. Forty-six cases of Chlamydophila psittaci infection with atypical pneumonia of varying severity in the last two years were described retrospectively.

RESULTS

Fever, relative bradycardia, and other systemic upsets were the main clinical presentation. The most common radiographic abnormality was segmental or lobar shadowing or consolidation. The total white cell counts were usually normal or slightly increased. The concentration of creatine kinase, C reactive protein, and lactic dehydrogenase increased, while albumin decreased remarkably. These cases exhibited good recovery after being treated with tetracycline or quinolone antibiotics.

CONCLUSION

These features may help differentiate psittacosis from other traditional bacterial pneumonia. However, they do not provide a definitive diagnosis. Psittacosis diagnosis must perform the whole-genome sequencing for Chlamydophila psittaci in respiratory, blood, or sputum specimens. Increased awareness of psittacosis can shorten diagnostic delays and improve patient outcomes.

Computational exploration and design of a multi-epitopes vaccine construct against Chlamydia psittaci

Chlamydia psittaci is an intracellular pathogen and causes variety of deadly infections in humans. Antibiotics are effective against C. psittaci however high percentage of resistant strains have been reported in recent times. As there is no licensed vaccine, we used in-silico techniques to design a multi-epitopes vaccine against C. psittaci. Following a step-wise protocol, the proteome of available 26 strains was retrieved and filtered for subcellular localized proteins. Five proteins were selected (2 extracellular and 3 outer membrane) and were further analyzed for B-cell and T-cell epitopes prediction. Epitopes were further checked for antigenicity, solubility, stability, toxigenicity, allergenicity, and adhesive properties. Filtered epitopes were linked via linkers and the 3D structure of the designed vaccine construct was predicted. Binding of the designed vaccine with immune receptors: MHC-I, MHC-II, and TLR-4 was analyzed, which resulted in docking energy scores of -4.37 kcal/mol, -0.20 kcal/mol and -22.38 kcal/mol, respectively. Further, the docked complexes showed stable dynamics with a maximum value of vaccine-MHC-I complex (7.8 Å), vaccine-MHC-II complex (6.2 Å) and vaccine-TLR4 complex (5.2 Å). As per the results, the designed vaccine construct reported robust immune responses to protect the host against C. psittaci infections. In the study, the C. psittaci proteomes were considered in pan-genome analysis to extract core proteins. The pan-genome analysis was conducted using bacterial pan-genome analysis (BPGA) software. The core proteins were checked further for non-redundant proteins using a CD-Hit server. Surface localized proteins were investigated using PSORTb v 3.0. The surface proteins were BLASTp against Virulence Factor Data Base (VFDB) to predict virulent factors. Antigenicity prediction of the shortlisted proteins was further done using VAXIGEN v 2.0. The epitope mapping was done using the immune epitope database (IEDB). A multi-epitopes vaccine was built and a 3D structure was generated using 3Dprot online server. The docking analysis of the designed vaccine with immune receptors was carried out using PATCHDOCK. Molecular dynamics and post-simulation analyses were carried out using AMBER v20 to decipher the dynamics stability and intermolecular binding energies of the docked complexes.Communicated by Ramaswamy H. Sarma.

Co-infection of Chlamydia psittaci and Tropheryma whipplei: A case report

BACKGROUND

The co-infection of Chlamydia psittaci (C. psittaci) and Tropheryma whipplei (T. whipplei) is unusual, and the detection of pathogenic microorganisms is particularly important for patients with severe diseases or poor experience in treatment. Early identification of pathogens can significantly improve the prognosis of the patients. Targeted next-generation sequencing (tNGS) is currently widely used in clinical practice for various infectious diseases, including respiratory infections, to achieve early, accurate, and rapid microbial diagnosis.

CASE SUMMARY

We report a case of a 40-year-old female patient with a history of contact with parrots who was diagnosed with C. psittaci and T. whipplei infection through bronchial lavage fluid targeted next generation sequencing. After moxifloxacin treatment, the patient's symptoms improved significantly, and the imaging changes were obviously resolved.

CONCLUSION

Coinfection with C. psittaci and T. whipplei is not common. In this case, timely and accurate identification of both pathogens was achieved using tNGS. Moreover, the efficacy of monotherapy with moxifloxacin was confirmed.

Acute abdominal pain as the first symptom of Chlamydia psittaci pneumonia complicated by acute pancreatitis: a case report

Background

Chlamydia psittaci infections primarily cause damage to the lungs but may also affect the cardiovascular system, gastrointestinal tract, liver, kidney, and brain, resulting in a variety of extrapulmonary complications. However, reports regarding C. psittaci infection-associated pancreatitis are rare. In this report, a patient with C. psittaci pneumonia complicated by acute pancreatitis is presented.

Case description

The patient presented with acute upper abdominal pain and developed severe pyrexia and dyspnoea one day later. A chest computed tomography image revealed patchy consolidation in the left lung. The disease progressed rapidly, and the patient exhibited liver and kidney damage and type 1 respiratory failure within a short period of time. Metagenomic next-generation sequencing of alveolar lavage fluid revealed the presence of C. psittaci. The patient was administered doxycycline and moxifloxacin, after which the patient's abdominal pain and lung infection significantly resolved.

Conclusion

This case report demonstrates that extrapulmonary C. psittaci infections due to secondary acute pancreatitis can manifest as abdominal pain, although the exact mechanisms of C. psittaci caused by acute pancreatitis remain unclear. Timely diagnoses and treatments of such infections are necessary to achieve favorable clinical outcomes.

Successful treatment of near-fatal pulmonary embolism and cardiac arrest in an adult patient with fulminant psittacosis-induced severe acute respiratory distress syndrome after veno-venous extracorporeal membrane oxygenation rescue: A case report and follow-up

Background

Veno-venous extracorporeal membrane oxygenation (ECMO) was successfully performed for the rescue of an adult patient with severe acute respiratory distress syndrome (ARDS) induced by fulminant psittacosis, and then a near-fatal pulmonary embolism (PE) and cardiac arrest (CA) of the same patient was cured through catheter-directed thrombolysis.

Case presentation

A 51-year-old female patient was admitted to the hospital on September 10, 2021 due to slurred speech, weakness in lower limbs, dizziness, and nausea. Subsequently, she developed confusion and was transferred to the intensive care unit (ICU), where she received anti-shock, antibiotics, invasive mechanical ventilation (IMV), and veno-venous ECMO due to the diagnosis of severe pneumonia, severe ARDS, and septic shock based on comprehensive physical examination, laboratory tests, and imaging findings. The metagenomic next-gengeration sequencing (m-NGS) in the bronchoalveolar lavage fluid (BALF) suggested that the pathogen was chlamydia psittaci, so the antibiotics were adjusted to doxycycline combined with azithromycin. After withdrawal from ECMO, ultrasound (US) re-examination of the left lower limb revealed inter-muscular vein thrombosis, following which heparin was replaced by subcutaneous injection of 0.4ml enoxaparin sodium twice daily for anti-coagulation therapy. After withdrawal from IMV, the patient suffered sudden CA and successful cardiopulmonary resuscitation (CPR), and emergency pulmonary angiography (PA) was performed to show bilateral main pulmonary artery embolism. After immediate catheter-directed thrombolysis and placement of an inferior vena cava filter, the patient's condition gradually stabilized.

Conclusions

Veno-venous ECMO can be successfully performed as an emergency life-saving treatment for patients with severe ARDS induced by fulminant psittacosis, and during ECMO regular examinations should be conducted to detect and manage thrombosis in time, thereby avoiding the occurrence of near-fatal PE and CA.

Chlamydia psittaci seropositivity in workers exposed to birds and review of the literature: Evidence of circulation in Antioquia

Introduction

Psittacosis is a zoonotic disease caused by Chlamydia psittaci, a bacterium classified as an agent with bioterrorist potential. It has caused multiple outbreaks in exposed poultry workers around the world. Colombia has no epidemiological follow-up of the infection and a big knowledge gap.

Objectives

To determine the antibodies’ frequency against C. psittaci in workers with occupational exposure to birds and to review the literature on studies conducted in Colombia.

Materials and methods

We conducted a cross-sectional descriptive study with analytical intent on workers in contact with birds and reviewed the related literature in Colombia. IgM and IgG serum antibodies against C. psittaci were detected by microimmunofluorescence. The sociodemographic and exposure characteristics were expressed as frequencies and summary measures. Associated factors were explored by bivariate and multivariate analysis. The scientific and gray literature review was done with a structured search.

Results

We analyzed 54 workers in contact with birds. Antibody prevalence was 31.5%. Slaughtering and evisceration by non-veterinarians was a risk factor for antibody presence. There are only four previous studies on C. psittaci in Colombia.

Conclusions

Here, we present the first evidence of C. psittaci circulation among workers exposed to birds in Antioquia and the second report in the country. These findings contribute to the “One Health” public health strategy.

Clinical analysis of severe Chlamydia psittaci pneumonia: Case series study

The clinical characteristics and diagnosis of ten cases with severe Chlamydia psittaci pneumonia were analyzed. Ten patients had high fever, cough, or diarrhea, and all had a history of contact with birds or poultry. The white blood cell count of the patients was normal or slightly increased. The percentage of neutrophils (N%) and C reactive protein of the patients were significantly increased. Chest computer tomography showed patchy consolidation of both lungs, with one-sided lung lobes prominent, and bronchial inflation signs. All the patients were admitted to the intensive care unit due to respiratory failure. Nine patients needed ventilator-assisted ventilation therapy, and one patient needed high-flow oxygen therapy. All patients had sepsis, and five patients developed septic shock. The patients were diagnosed with severe C. psittaci pneumonia by clinical manifestations and contact history. After timely adjustment of tetracycline-based treatment, eight patients recovered and were discharged, and two patients died of septic shock and respiratory failure. Patients with poultry contact should be cautious toward C. psittaci pneumonia. A better method for the detection of C. psittaci is metagenomic next-generation sequencing. Its examination can shorten the diagnosis time. In a later stage, large-sample research is needed to guide clinical diagnosis and treatment.

Psittacosis: An Underappreciated and Often Undiagnosed Disease

The bacterial agent Chlamydia psittaci, and the resulting disease of psittacosis, is a little-known and underappreciated infectious disease by healthcare practitioners and in public health in general. C. psittaci infections can cause significant psittacosis outbreaks, with person-to-person transmission documented in the last decade. In this publication, we review the pathogen and its disease, as well as examine the potential for genetic manipulation in this organism to create a more deadly pathogen. Recent disease surveys indicate that currently, the highest incidences of human disease exist in Australia, Germany and the UK. We recommend the universal public health reporting of C. psittaci and psittacosis disease and increasing the promotion of public health awareness.

Epidemiological and clinical characteristics of psittacosis among cases with complicated or atypical pulmonary infection using metagenomic next-generation sequencing: a multi-center observational study in China

BACKGROUND

Chlamydia psittaci (C. psittaci) causes parrot fever in humans. Development of metagenomic next-generation sequencing (mNGS) enables the identification of C. psittaci.

METHODS

This study aimed to determine the epidemiological and clinical characteristics of parrot fever cases in China. A multi-center observational study was conducted in 44 tertiary and secondary hospitals across 14 provinces and municipalities between April 2019 and October 2021.

RESULTS

A total of 4545 patients with complicated or atypical pulmonary infection were included in the study, among which the prevalence of C. psittaci was determined to be 2.1% using mNGS. The prevalence of C. psittaci was further determined across demographic groups and types of specimens. It was significantly higher in patients with senior age (2.6% in those > 50 years), winter-spring (3.6%; particularly in December, January, and February), and southwestern (3.4%) and central and southern China (2.7%) (each P < 0.001). Moreover, the prevalence was the highest in bronchoalveolar lavage fluid (BALF) (2.9%), compared with sputum (1.1%) and peripheral blood specimens (0.9%). Additionally, co-infection of principal microorganisms was compared. Certain microorganisms were more likely to co-infect in parrot fever cases, such as Candida albicans in BALF (26.7%) and peripheral blood (6.3%), compared with non-parrot fever cases (19.7% and 1.3%); however, they did not significantly differ (each P > 0.05).

CONCLUSION

Parrot fever remains low in patients with complicated or atypical pulmonary infection. It is likely to occur in winter-spring and southwestern region in China. BALF may be the optimal specimen in the application of mNGS. Co-infection of multiple microorganisms should be further considered.

A pediatric case of Chlamydia psittaci caused severe Acute Respiratory Distress Syndrome (ARDS) in Italy

BACKGROUND

This case of psittacosis in children, is the first described in literature, in Italy. This respiratory infection can be transmitted to humans from the inhalation of respiratory secretions, feces and plumage aerosol of infected birds (and other animals). Usually it can have an asymptomatic or paucisymptomatic course, and the onset is often flu-like, but in this case the child risked his life for a severe respiratory failure. This report is unique because in children psittacosis is rare, and always misdiagnosed, or could cause a delayed diagnosis because of lack of awareness among the paediatricians and physicians. Furthermore, psittacosis enters a differential diagnosis with SARS-COV2 infection because both diseases may determine dyspnea and atypical pneumonia, up to acute respiratory failure.

CASE PRESENTATION

This clinical case talks about a three-and-a-half-year-old male child affected by psittacosis (or ornithosis), with severe dyspnea and systemic symptoms who required oro-tracheal intubation for acute respiratory failure. The child had slept in a room at home, with some recently bought parrots affected by psittacosis. Initially the child was treated with empiric antibiotic therapy (i.v.ceftriaxone and teicoplanin), but after having isolated the DNA of the germ "Chlamydia psittaci" in both serological and through bronchoalveolar lavage (BAL), he was treated with targeted antibiotic therapy: tetracyclines (doxicillin).

CONCLUSIONS

Psittacosis is an extremely contagious disease, caused by an intracellular germ, called "Chlamydia psittaci", a Gram-negative bacterium, transmitted to humans in particular by infected birds, responsible for atypical pneumonia, with acute and chronic respiratory symptoms, sometimes with multi-organ failure and disseminated intravascular coagulation. Even if it is a rare respiratory disease among children, a good doctor must think about psittacosis as cause of respiratory symptoms (and not only flu or SARS-COV2), above all through a correct medical history, in order to provide a targeted antibiotic therapy. An interesting case of psittacosis in a child is being reported here, which has been treated successfully with doxycillin.

Evaluation of a biosecurity survey approach for contamination by Chlamydia pecorum in koala rehabilitation, field capture, and captive settings

Transmission of Chlamydia pecorum between koalas is a potential risk in field capture or rehabilitation settings, where koalas are held in proximity to each other, or equipment is shared between animals. Given the impact of C. pecorum on koala welfare and population viability it is surprising that quarantine and disinfection protocols in a koala rehabilitation facility or capture settings have not previously been evaluated. This study aimed to evaluate an approach, based on the detection of chlamydial DNA and cell viability, to determine the degree of environmental contamination within a koala care facility. Various fomite sites associated with koala care at a koala rehabilitation facility in New South Wales, Australia were identified as potential sources of chlamydial contamination, following exposure to koalas known to be infected with C. pecorum. Fomite sites were swabbed following exposure, and again after decontamination procedures were carried out. Samples were tested for the presence of chlamydial DNA using qPCR and viability using both RT-qPCR and cell culture. From a total of 239 sampling events, 30 tested qPCR positive for chlamydial DNA, with 19 and 11 samples corresponding to pre-decontamination and post-decontamination events respectively. Detection of chlamydial DNA appeared to be most common in the examination room, especially on fomite sites in direct contact with koalas. Physical removal of chlamydial DNA, or its degradation by the elements, appeared to be more common on outdoor enclosures, clothing, and hands. Based on the cell culture assay, of the pre-decontamination samples with chlamydial DNA, eight had viable chlamydial cells, two of these at low levels. Of the post-decontamination samples with chlamydial DNA, one had a moderate number, and one had a very low number of viable chlamydial cells. RT-qPCR was unsuccessful in determining cell viability due to low yields of RNA and high levels of contaminants from the environmental samples. The outcomes of this study provide a knowledge base for the design of future biosecurity evaluation guidelines in captive and koala rehabilitation facilities. The higher incidence of chlamydial DNA detection by qPCR than viable organism highlights the need to use viability assays in similar studies. However, further investment is still needed to optimise these methods and improve sensitivity for complex environmental samples.

Psittacosis caused severe community-acquired pneumonia accompanied by acute hypoxic respiratory failure: a multicenter retrospective cohort study from China

INTRODUCTION

Psittacosis can cause severe community-acquired pneumonia (CAP). The clinical manifestations of psittacosis range from subclinical to fulminant psittacosis with multi-organ failure. It is essential to summarize the clinical characteristic of patients with severe psittacosis accompanied by acute hypoxic respiratory failure (AHRF).

METHODS

This retrospective study included patients with severe psittacosis caused CAP accompanied by AHRF from 19 tertiary hospitals of China. We recorded the clinical data, antimicrobial therapy, respiratory support, complications, and outcomes. Chlamydia psittaci was detected on the basis of metagenomic next-generation sequencing performed on bronchoalveolar lavage fluid samples. Patient outcomes were compared between the treatment methods.

RESULTS

This study included 45 patients with severe CAP and AHRF caused by psittacosis from April 2018 to May 2021. The highest incidence of these infections was between September and April. There was a history of poultry contact in 64.4% of the patients. The median PaO2/FiO2 of the patients was 119.8 (interquartile range, 73.2 to 183.6) mmHg. Four of 45 patients (8.9%) died in the ICU, and the median ICU duration was 12 days (interquartile range, 8 to 21) days. There were no significant differences between patients treated with fluoroquinolone initially and continued after the diagnosis, fluoroquinolone initially followed by tetracycline, and fluoroquinolone combined with tetracycline.

CONCLUSION

Psittacosis caused severe CAP seems not rare, especially in the patients with the history of exposure to poultry or birds. Empirical treatment that covers atypical pathogens may benefit such patients, which fluoroquinolones might be considered as an alternative.

Case Report: Clinical analysis of a cluster outbreak of chlamydia psittaci pneumonia

Objective

To explore the clinical characteristics and prognosis of clustered cases of psittacosis pneumonia.

Method

We retrospectively analyzed the clinical data of a cluster outbreak of psittacosis pneumonia. The analysis included epidemiological data, clinical symptoms, laboratory results, and prognosis. The diagnosis was made using mNGS and nested PCR technology.

Result

Of the four cases, two had direct contact with diseased poultry while the other two did not. All cases presented with more than 39.5 °C fever and chills. Additionally, significant increases in C-reactive protein, ferritin, creatine kinase, and lactate dehydrogenase were observed in all cases, while absolute lymphocyte count decreased. Case 2 also had increased calcitonin levels. Acute respiratory failure occurred during the treatment of case 1 and case 2, leading to tracheal intubation and ventilator-assisted ventilation. Unfortunately, case 2 passed away due to sepsis and multiple organ dysfunction, while the other cases had a positive prognosis.

Conclusion

mNGS facilitated the early diagnosis of psittacosis pneumonia. It is important to note that there is still a substantial risk of human-to-human transmission in psittacosis pneumonia. Absolute lymphocyte count and calcitonin levels can predict the severity and prognosis of the disease.

Equine Psittacosis and the Emergence of Chlamydia psittaci as an Equine Abortigenic Pathogen in Southeastern Australia: A Retrospective Data Analysis

Chlamydia psittaci is an important zoonotic pathogen. Although primarily a pathogen of birds, from which infection can spillover into humans and other mammalian hosts, the importance of C. psittaci as a cause of equine reproductive loss and the risk of infection to humans in contact with infected horses are increasingly being recognised in Australia and elsewhere. Despite the risks to both human and equine health, C. psittaci infection in horses is incompletely understood. This study aimed to update and summarise cases of equine psittacosis in Australia in the period 2018-2022, thus addressing a knowledge gap relating to recent cases in this country. These cases were identified from the examination of records held by state and federal veterinary authorities and from a review of published cases. A total of 31 cases were identified. Spatial and temporal trends were identified, with cases being more prevalent in winter and spring and geographically restricted to Victoria and New South Wales. The results show that cases of equine reproductive loss due to C. psittaci are consistent and ongoing and demonstrate the importance of routinely considering C. psittaci in diagnostic investigations. The need for ongoing study to better understand this important zoonotic pathogen is evident.

Multiplex Real-time PCR Assay for the Detection of all Chlamydia Species and Simultaneous Differentiation of C. psittaci and C. pneumoniae in Human Clinical Specimens

We developed and assessed the performance of a new multiplex real-time PCR assay for the detection of all Chlamydia species and simultaneous differentiation of Chlamydia psittaci and Chlamydia pneumoniae-two important human respiratory pathogens-in human clinical specimens. Next-generation sequencing was used to identify unique targets to design real-time PCR assays targeting all Chlamydia species, C. psittaci, and C. pneumoniae. To validate the assay, we used a panel of 49 culture isolates comprising seven C. psittaci genotypes, eight C. pneumoniae isolates, seven other Chlamydia species, and 22 near-neighbor bacterial and viral isolates, along with 22 specimens from external quality assessment (EQA) panels and 34 nasopharyngeal and oropharyngeal swabs and cerebrospinal fluid, stool, and sputum specimens previously identified as positive or negative for C. psittaci or C. pneumoniae. The assays were 100% specific, with limits of detection of 7.64- 9.02 fg/μL. The assay results matched with historical assay results for all specimens, except for one owing to the increased sensitivity of the new C. psittaci assay; the results of the EQA specimens were 100% accurate. This assay may improve the timely and accurate clinical diagnosis of Chlamydia infections and provide a greater understanding of the burden of disease caused by these agents.

Chlamydia Psittaci Pneumonia-Induced Myocarditis: A Case Report

The incidence of Chlamydia psittaci infection has been reported to increase in recent years. The presentation of psittacosis infection varied widely, from none to severe symptoms. Mainly, psittacosis infection presents with pulmonary manifestations. Here, we report the case of a 60-year-old female patient with Chlamydia psittaci pneumonia complicated by myocarditis. After administering antibiotics, the patient recovered from severe atypical pneumonia and myocarditis. In general, Chlamydia psittaci rarely induces myocarditis. Moreover, the optimal therapeutic strategies remain unclear for such cases, especially with a high troponin T level. Metagenomic Next-Generation Sequencing (mNGS) can provide a quick and effective diagnosis of Chlamydia psittaci pneumonia; early intervention (antibiotic therapy and nutritional supplements for myocarditis) favors a good outcome, although complications may worsen the condition. Therefore, more studies are required to help improve understanding of the disease.