COVID-19-associated acute renal failure in critically ill patients correlates with microthrombosis and renal loss of thrombomodulin (preprint)

Critically ill COVID-19 patients have a high degree of acute kidney injury which develops in up to 85% of patients. We have previously shown that circulating levels of angiopoietin-2 increased in critically ill COVID-19 patients correlated to kidney injury, coagulopathy, and mortality. Furthermore, our experiments showed a causal effect on coagulopathy from angiopoietin-2 binding and inhibition of thrombomodulin mediated anticoagulation. In the current study we hypothesize that renal microthrombi may be a mechanism for reduced renal function in critically ill COVID-19 patients, and that local dysregulation of thrombomodulin and angiopoietin-2 may be involved. To investigate our hypothesis, we utilized postmortem kidney tissue from seven COVID-19 patients treated at the intensive care unit. We evaluated kidney function, thrombosis, tubular injury, fibrosis, glomerulosclerosis, glomerular size as well as renal expression of thrombomodulin and angiopoietin-2. Proximity ligation assay was utilized to evaluate the presence of angiopoietin-2 binding to thrombomodulin. Normal kidney tissue came from the healthy part of six nephrectomies due to cancer. Our experiments show renal thrombosis in 6/7 COVID-19 patients, on average 14.7 (6.9-22.5) thrombi per mm2. Most COVID-19 kidneys had extensive kidney injury, especially tubular necrosis, but also glomerular enlargement, glomerulosclerosis, and tubulointerstitial fibrosis which in some cases most likely resulted from underlying disease. Thrombomodulin expression was reduced in glomeruli and peritubular capillaries in kidneys from COVID-19 patients, whereas no change was found for angiopoietin-2. In summary, our study describes a high degree of acute renal failure, renal microthrombosis, and loss of thrombomodulin in postmortem tissue from critically ill COVID-19 patients.

Successful Treatment of Post-COVID-19 Severe ANCA-Associated Vasculitis: Case Report (preprint)

Background The SARS-CoV-2 pandemic has become the most serious health problem of today globally. Kidney involvement in patients with coronavirus disease 2019 (COVID-19) is common and associated with high mortality. Although acute tubular necrosis due to hemodynamic instability is the most common cause, other complex and destructive processes related to cytokine storm and activation of innate and adaptive immunity have also been reported.Case presentation: Herein, we present successful treatment of proteinase-3 anti-neutrophil cytoplasmic antibodies (PR3-ANCA)-associated vasculitis case presenting with severe pulmonary-renal syndrome as a rare and fatal complication of COVID-19 infection.Conclusions AAV is a serious disease and prompt treatment is one of the most important factors in patient survival.

Clinical and chest computed tomography features associated with severe Chlamydia psittaci pneumonia diagnosed by metagenomic next-generation sequencing: A multicenter, retrospective, observational study.

Chlamydia psittaci pneumonia is a rare disease with varying clinical presentations. Here, we aimed to investigate the clinical and chest computed tomography (CT) features of severe psittacosis pneumonia. Clinical data of 35 patients diagnosed with psittacosis pneumonia were retrospectively analyzed using metagenomic next-generation sequencing. The patients were classified into severe (n = 20) and non-severe (n = 15) groups. The median age of patients was 54 years, and 27 patients (77.1%) had a definite history of bird contact. Severe patients had more underlying comorbidities and were more prone to dyspnea and consciousness disorders than non-severe patients. The neutrophil count and D-dimer, lactate dehydrogenase, interleukin (IL)-2, IL-6, and IL-10 levels were higher, whereas the lymphocyte, CD3 + T cell, and CD4 + T cell counts, CD4+/CD8 + T cell ratio, and albumin level were substantially lower in severe patients than in non-severe patients. Chest CT findings of severe patients revealed large areas of pulmonary consolidation, and ground-glass opacities were observed in some patients, with a higher risk of involving multiple lobes of the lungs and pleural effusion. One patient died of multiple organ failure, whereas the condition of the other 34 patients improved, and they were discharged from the hospital. Patients with severe psittacosis pneumonia often have underlying comorbidities and are prone to developing dyspnea, consciousness disorder, and lesions in both lungs. Serum D-dimer, IL-2, IL-6, and IL-10 levels and lymphocyte, CD3 + T cell, and CD4 + T cell counts are associated with disease severity.

Human-to-human transmission of Chlamydia psittaci in China, 2020: an epidemiological and aetiological investigation.

BACKGROUND: Chlamydia psittaci can infect a wide range of avian species, occasionally causing psittacosis (also known as parrot fever) in humans. Most human psittacosis cases are associated with close contact with pet birds or poultry. In December, 2020, an outbreak of severe community-acquired pneumonia of unknown aetiology was reported in a hospital in Shandong province, China, and some of the patients' close contacts had respiratory symptoms. Our aims were to determine the causative agent of this epidemic and whether there had been human-to-human transmission. METHODS: For this epidemiological and aetiological investigation study, we enrolled patients who had community-acquired pneumonia confirmed by chest CT at two local hospitals in Shandong Province in China. We collected sputum, bronchoalveolar lavage fluid, and nasopharyngeal swab samples from participants and detected pathogens by surveying for 22 target respiratory microbes using a commercial assay, followed by metagenomic next-generation sequencing, specific nested PCR, and qPCR tests. We excluded individuals who were C psittaci-negative on both tests. We recruited close contacts of the C psittaci-positive patients, and tested nasopharyngeal swabs from the close contacts and samples from ducks from the processing plant where these patients worked. We then integrated the epidemiological, clinical, and laboratory data to reveal the potential chain of transmission of C psittaci that characterised this outbreak. FINDINGS: Between Dec 4 and 29, 2020, we used metagenomic next-generation sequencing and different PCR-based approaches to test 12 inpatients with community-acquired pneumonia, of whom six (50%) were workers at a duck-meat processing plant and two (17%) were unemployed people, who were positive for C psittaci and enrolled in this study. We contacted 61 close contacts of the six patients who worked at the duck-meat processing plant, of whom 61 (100%) were enrolled and tested, and we determined that the community-acquired pneumonia outbreak was caused by C psittaci. Within the outbreak cluster, 17 (77%) of 22 participants had confirmed C psittaci infections and five (23%) of 22 participants were asymptomatic C psittaci carriers. The outbreak had begun with avian-to-human transmission, and was followed by secondary and tertiary human-to-human transmission, which included transmission by several asymptomatic carriers and by health-care workers. In addition, some of the participants with confirmed C psittaci infection had no identified source of infection, which suggested cryptic bacterial transmission. INTERPRETATION: Our study data might represent the first documented report of human-to-human transmission of C psittaci in China. Therefore, C psittaci has the potential to evolve human-to-human transmission via various routes, should be considered an elevated biosecurity and emergent risk, and be included as part of the routine diagnosis globally, especially for high-risk populations. FUNDING: Academic Promotion Programme of Shandong First Medical University, National Science and Technology Major Project, ARC Australian Laureate Fellowship.

Atypical pneumonia caused by Chlamydia psittaci during the COVID-19 pandemic.

OBJECTIVES: Here, we retrospectively described the diagnosis and treatment of 32 cases diagnosed with Chlamydia psittaci pneumonia during the COVID-19 pandemic. METHODS: Clinical information was collected from all the patients. Reverse transcription-PCR and ELISAs were conducted for the detection of COVID-19 using nasal swabs and bronchoalveolar lavage fluid (BALF) samples. Metagenomic next-generation sequencing (mNGS) was performed for the identification of causative pathogens using BALF, peripheral blood and sputum samples. End-point PCR was performed to confirm the mNGS results. RESULTS: All 32 patients showed atypical pneumonia and had infection-like symptoms that were similar to COVID-19. Results of reverse transcription-PCR and ELISAs ruled out COVID-19 infection. mNGS identified C. psittaci as the suspected pathogen in these patients within 48 hours, which was validated by PCR, except for three blood samples. The sequence reads that covered fragments of C. psittaci genome were detected more often in BALF than in sputum or blood samples. All patients received doxycycline-based treatment regimens and showed favorable outcomes. CONCLUSION: This retrospective study, with the highest number of C. psittaci pneumonia enrolled cases in China so far, suggests that human psittacosis may be underdiagnosed and misdiagnosed clinically, especially in the midst of the COVID-19 pandemic.

Comparative Study of HRCT Imaging Characteristics of Psittaci Pneumonia and COVID-19 Pneumonia (preprint)

Backgroud : Both Chlamydia psittaci and COVID-19 virus can cause lung inflammation, which manifests extremely similarly in clinical symptoms and imaging. Especially during the epidemic of COVID-19, psittacosis pneumonia is easily misdiagnosed as COVID-19 pneumonia. The identification of the chest imaging between the two diseases is of special significance when the epidemiological contact history is unclear, and the etiology and nucleic acid test results are not available. This study conducts to compare the imaging characteristics on chest high-resolution CTs (HRCT) between patients with psittaci pneumonia and COVID-19 pneumonia. Methods: : A retrospective analysis of the imaging characteristics on chest HRCTs of 10 psittaci pneumonia patients and 13 COVID-19 pneumonia patients. The similarities and differences in HRCT images of patients with psittaci pneumonia and COVID-19 pneumonia were analyzed. Results: : HRCT showed that among the 10 psittaci pneumonia patients, 8 cases (80.00%) had single lobe involvement, and 2 cases (20.00%) had multiple lobe involvement. Among the 13 COVID-19 pneumonia patients, 2 cases had single lobe involvement (15.38%), and 11 cases had multiple lobe involvement (84.62%). The types of lesions in 10 psittaci pneumonia patients included simple consolidation in 5 cases (50.00%), and ground-glass opacity (GGO) with consolidation in 5 cases (50.00%). The types of lesions in 13 COVID-19 pneumonia patients included simple GGO in 6 cases (46.15%), GGO with consolidation in 4 cases (30.77%), GGO with paving stone sign in 2 cases (15.38%), and simple consolidation in 1 case (7.69%). Lymphadenopathy was observed in 1 psittaci pneumonia patient (10.00%) and 1 COVID-19 pneumonia patient (7.69%). Among the 10 psittaci pneumonia patients, 8 cases (80.00%) had bronchial inflation, and 6 patients (60.00%) had pleural effusion. Among the 13 COVID-19 pneumonia patients, 5 patients (38.46%) showed signs of bronchial inflation, while no pleural effusion was observed in 13 patients. Conclusion: : Chest HRCTs can distinguish COVID-19 pneumonia from psittaci pneumonia, and can provide early diagnoses of these two diseases.

Metagenomic next-generation sequencing in the family outbreak of psittacosis: the first reported family outbreak of psittacosis in China under COVID-19.

Chlamydia psittaci infection in humans, also known as psittacosis, is usually believed to be an uncommon disease which mainly presents as community-acquired pneumonia (CAP). It is usually sporadic, but outbreaks of infection may occasionally occur. In outbreaks, diagnosis and investigations were usually hampered by the non-specificity of laboratory testing methods to identify C. psittaci. In this study, we use metagenomic next-generation sequencing (mNGS) in the diagnosis of a family outbreak of psittacosis under COVID-19. Three members of an extended family of 6 persons developed psittacosis with pneumonia and hepatic involvement with common symptoms of fever and weakness. Two newly purchased pet parrots, which had died successively, were probably the primary source of infection. Imagings show lung consolidations and infiltrates, which are difficult to be differentiated from CAP caused by other common pathogens. mNGS rapidly identified the infecting agent as C. psittaci within 48 h. The results of this work suggest that there are not characteristic clinical manifestations and imagings of psittacosis pneumonia which can differentiate from CAP caused by other pathogens. The use of mNGS can improve accuracy and reduce the delay in the diagnosis of psittacosis especially during the outbreak, which can shorten the course of the disease control. Family outbreak under COVID-19 may be related to the familial aggregation due to the epidemic. To our knowledge, this is the first reported family outbreak of psittacosis in China, and the first reported psittacosis outbreak identified by the method of mNGS in the world.