ABSTRACT
OBJECTIVE: To understand the status of generation and management of medical waste in medical institutions of Chongqing. METHODS: By means of onsite investigation and questionnaire survey, the generation categories and current status of management of medical waste in 50 medical institutions were investigated from Oct 2021 to Apr 2022 the existing limitations and prominent problems in the whole-process management of medical waste were identified so as to enable the safe disposal of medical waste based on laws and regulations. RESULTS: The average pollutants generation coefficient of medical waste was 0.22-0.72 kg/bed.day among all the grades of hospitals, the average pollutant generation coefficient of medical waste was 0.28-2.30 kg/10 people among grass-root medical institutions. The management of medical waste was more standardized in tertiary hospitals. There were a variety of problems in management of medical waste in clinics and village clinics, such as nonstandard classification of medical waste, unreasonable site selection for temporary storage of medical waste, unsatisfactory transportation means and untimely collection and transportation of medical waste. The problems of chemical, pharmaceutical and pathological medical waste were more prominent. The costs of disposal of medical waste were not strictly implemented in accordance with standards. The packaging, storage, loading, handover and disinfection of COVID-19 medical waste have been carried out in accordance with regulations. CONCLUSION: It is necessary to further standardize the management of medical waste, explore and formulate the collection and transportation modes of medical waste in primary medical institutions, intensify the supervision of classification, collection, storage, transportation and disposal of medical waste, optimize and upgrade the medical waste management information system, and encourage subsidies for the disposal of medical waste in Chongqing medical waste disposal enterprises during the COVID-19 period.
ABSTRACT
The Chinese horseshoe bat (Rhinolophus sinicus), reservoir host of severe acute respiratory syndrome coronavirus (SARS-CoV), carries many bat SARS-related CoVs (SARSr-CoVs) with high genetic diversity, particularly in the spike gene. Despite these variations, some bat SARSr-CoVs can utilize the orthologs of the human SARS-CoV receptor, angiotensin-converting enzyme 2 (ACE2), for entry. It is speculated that the interaction between bat ACE2 and SARSr-CoV spike proteins drives diversity. Here, we identified a series of R. sinicus ACE2 variants with some polymorphic sites involved in the interaction with the SARS-CoV spike protein. Pseudoviruses or SARSr-CoVs carrying different spike proteins showed different infection efficiencies in cells transiently expressing bat ACE2 variants. Consistent results were observed by binding affinity assays between SARS-CoV and SARSr-CoV spike proteins and receptor molecules from bats and humans. All tested bat SARSr-CoV spike proteins had a higher binding affinity to human ACE2 than to bat ACE2, although they showed a 10-fold lower binding affinity to human ACE2 compared with that of their SARS-CoV counterpart. Structure modeling revealed that the difference in binding affinity between spike and ACE2 might be caused by the alteration of some key residues in the interface of these two molecules. Molecular evolution analysis indicates that some key residues were under positive selection. These results suggest that the SARSr-CoV spike protein and R. sinicus ACE2 may have coevolved over time and experienced selection pressure from each other, triggering the evolutionary arms race dynamics.IMPORTANCE Evolutionary arms race dynamics shape the diversity of viruses and their receptors. Identification of key residues which are involved in interspecies transmission is important to predict potential pathogen spillover from wildlife to humans. Previously, we have identified genetically diverse SARSr-CoVs in Chinese horseshoe bats. Here, we show the highly polymorphic ACE2 in Chinese horseshoe bat populations. These ACE2 variants support SARS-CoV and SARSr-CoV infection but with different binding affinities to different spike proteins. The higher binding affinity of SARSr-CoV spike to human ACE2 suggests that these viruses have the capacity for spillover to humans. The positive selection of residues at the interface between ACE2 and SARSr-CoV spike protein suggests long-term and ongoing coevolutionary dynamics between them. Continued surveillance of this group of viruses in bats is necessary for the prevention of the next SARS-like disease.