Case report: histopathology and molecular pathology analysis on enteric tissue of a COVID-19 patient.

AIMS: Patients with COVID-19 can also have enteric symptoms. Here we analyzed the histopathology of intestinal detachment tissue from a patient with COVID-19. METHODS: The enteric tissue was examined by hematoxylin & eosin stain, PAS (Periodic acid-Schiff) staining, Gram staining, Ziehl-Neelsen stain and Grocott's Methenamine Silver (GMS) Stain. The distribution of CD3, CD4, CK20 and CD68, cytomegalovirus (CMV) and Herpes Simplex Virus (HSV) antigen were determined by immunohistochemistry. In situ hybridization (ISH) of SARS-CoV-2 and Epstein-Barr virus-encoded small RNA (EBER) were also performed. RESULTS: We observed mucosal epithelium shedding, intestinal mucosal erosion, focal inflammatory necrosis with hemorrhage, massive neutrophil infiltration, macrophage proliferation accompanied by minor lymphocyte infiltration. Fungal spores and gram positive cocci but not mycobacteria tuberculosis were identified. Immunohistochemistry staining showed abundant CD68+ macrophages but few lymphocytes infiltration. HSV, CMV and EBV were negative. ISH of SARS-CoV-2 RNA showed positive signal which mostly overlapped with CD68 positivity. CONCLUSIONS: The in situ detection of SARS-CoV-2 RNA in intestinal macrophages implicates a possible route for gastrointestinal infection. Further study is needed to further characterize the susceptibility of enteric cells to SARS-CoV-2 infection.

Analysis of pathogens and risk factors of secondary pulmonary infection in patients with COVID-19.

To investigate the distribution and risk factors of pathogens in secondary pulmonary infection in patients with COVID-19.142 patients with confirmed COVID-19 from Shanghai Public Health Clinical Center were collected, and 32 patients with pulmonary infection were taken as the infection group. The distribution of pathogens in the sputum specimens was applied for retrospective analysis. Meanwhile, 110 patients diagnosed with COVID-19, but without pulmonary infection were regarded as the asymptomatic group. The risk factors of pulmonary infection were analyzed with generalized linear models and logistic regression. The pathogens in the lung infection group were mainly gram-negative bacteria (22, 68.8%), especially Klebsiella pneumoniae. Gram-positive bacteria and fungi accounted for 13 (40.6%), mainly Staphylococcus aureus, and 11 (34.4%), mainly Candida albicans. There were 14 cases (43.8%) infected with two or more pathogens. The comparison between the two groups found that, patients with elder age, underlying diseases, more lung lesions and low protein contents, were more likely to develop lung infections. At last, univariate analysis showed that 6 factors, including indwelling gastric catheter, the number of deep vein catheters, tracheal intubation tracheotomy, invasive mechanical ventilation, hormonal application, and the use of more than three antibacterial drugs, are risk factors for COVID-19 secondary pulmonary infection. Generalized linear models and logistic regression analysis showed antimicrobial use as an independent risk factor for COVID-19 secondary lung infection. There are many risk factors for secondary lung infection in severe COVID-19 patients, and it is recommended to use antibiotics reasonably.

Pre-optimized phage therapy on secondary Acinetobacter baumannii infection in four critical COVID-19 patients.

Phage therapy is recognized as a promising alternative to antibiotics in treating pulmonary bacterial infections, however, its use has not been reported for treating secondary bacterial infections during virus pandemics such as coronavirus disease 2019 (COVID-19). We enrolled 4 patients hospitalized with critical COVID-19 and pulmonary carbapenem-resistant Acinetobacter baumannii (CRAB) infections to compassionate phage therapy (at 2 successive doses of 109 plaque-forming unit phages). All patients in our COVID-19-specific intensive care unit (ICU) with CRAB positive in bronchoalveolar lavage fluid or sputum samples were eligible for study inclusion if antibiotic treatment failed to eradicate their CRAB infections. While phage susceptibility testing revealed an identical profile of CRAB strains from these patients, treatment with a pre-optimized 2-phage cocktail was associated with reduced CRAB burdens. Our results suggest the potential of phages on rapid responses to secondary CRAB outbreak in COVID-19 patients.