Characteristic of Viral and Bacterial Contaminationin Objects of the Infection Hospital Environment of the Hospital for the Treatment of Patients with COVID-19 During the Pandemic Period
Authors: Egorov I. A. , Smirnova S. S. , Mishchenko V. A. , Vialykh I. V. , Markarian A. Yu. , Zhuikov N. N. , Romanov S. V. , Ponomareva A. V. , Chistiakova I. V. , Kiliachina A. S. , Averianov O. Yu. , Smirnova V. A. , Bolshakova А. N. , Vernik E. V. , Pushkareva N. A. , Semenov A. V. 
Published: January 2023

Relevance. Due to the COVID­-19 pandemic a infectious diseases hospitals nationwide network has been deployed to treat patients infected with SARS­CoV­-2. The principles of their formation with a strict division into «infectious» and «clean» zones, despite the epidemiological justification, lead to the formation of a dynamic artificially created closed ecosystem. In such an ecosystem, on the one hand, patients who undergo a wide range of invasive and aggressive therapeutic and diagnostic manipulations, and medical personnel stay for a long time, on the other hand, pathogens of a viral and bacterial nature that can adapt to hospital conditions and form resistant strains circulate. As a result, high risks of contamination of environmental objects of hospitals and patients themselves are created, which can lead to the development of exogenous nosocomial infection.

Aims. To study the features of viral and bacterial contamination of objects in the hospital environment of the infectious diseases hospital for the treatment of patients infected with SARS­-CoV­-2 during the COVID­-19 pandemic.

Materials and methods. A study was conducted on 343 samples from the external environment of the infectious diseases hospital for COVID­-19 patients’ treatment during its planned work. Sample collection was performed during three days (Tuesday, Thursday, Sunday) at 20 unified sampling points: in the area where patients general hospital area as well as from the outer surface of personal protective equipment for medical personnel (overalls, gloves). The study used epidemiological (descriptive­evaluative and analytical), molecular genetic (SARS-­CoV­-2 PCR­RT, sequencing), bacteriological (isolation, cultivation and MALDI­TOF identification of bacterial cultures) methods. Statistical significance of differences was assessed by Fisher's point test (φ). Differences were considered significant at p≤0.05. Statistical data processing was carried out using the Microsoft Office 2010 application package, the online resource https://medstatistic. ru/, ST Statistica 10.

Results. The study demonstrated a high level of viral and bacterial contamination of environmental objects in the intensive care unit of the infectious diseases hospital for COVID­-19 patients treatment – 11.1%, incl. objects of the general hospital environment – 9.3% (doctor's workplace – 16.7%); patient location area – 13.9% (electric pump – 27.8%, mechanical ventilation, manipulation table – 16.7% each); the outer surface of personnel gloves – 21.1–38.9%; the outer surface of protective overalls for personnel – 44.4–50.0%. SARS­-CoV­-2 isolated from the objects of the external environment of the hospital belonged to the genetic variant B.1.617.1 DELTA, which corresponded to the epidemiological situation at sampling collection period. The opportunistic microflora structure was dominated by Enterococcus faecalis (38.1%), Klebsiella pneumoniaе (21.4%) and Escherichia coli (16.7%), which demonstrated a high level of resistance (to 3 or more groups of antibiotics).

Conclusion. Initially, the main sources of the infectious diseases hospital environmental objects contamination with SARS-­CoV-­2 are most likely patients. Further contamination of the infectious diseases hospital environmental objects with viruses and opportunistic microflora occurs with the medical personnel direct participation. The current situation requires a review of approaches to the rules for disinfection, the PPE use and employees hands antiseptic treatment in infectious diseases hospital during the COVID­-19 pandemic, as well as the length of staff work period length.