Assessing changes in the pattern of healthcare-associated infectious agents in intensive care units during a novel coronavirus infection pandemic (COVID-19)

Introduction. The novel coronavirus infection (COVID-19) pandemic has been a major challenge to the global healthcare system, affecting more than 32 million patients worldwide. Unprecedented anti-epidemic measures carried out in hospitals allowed clinicians to hope for a decrease of hospital infection, however, the pandemic exacerbated the problem of the spread and circulation of multidrug-resistant bacteria in hospitals.   The goal of study to conduct a comparative assessment of changes in the microbial landscape and the level of antibiotic resistance of the main pathogens of lower respiratory tract infections in ICU patients who were in different epidemiological conditions during the COVID-19 pandemic in comparison with the “pre-Covid” period.   Materials and methods. A multicenter retrospective observational cohort study was conducted, which included the ICU of 4 hospitals in Yekaterinburg, which were in different epidemiological situations during the COVID-19 pandemic, as well as a comparative analysis of the length of stay of patients in the ICU, the frequency and duration of mechanical ventilation, the resuscitation mortality rate, and also the results of microbiological examination of sputum with an assessment of the structure of pathogens and the level of their antibiotic resistance.   Results. The structure of pathogens in sputum in ICU patients of the “green zone” has not fundamentally changed. In the “red zone” there was an increase in the number of documented infections of the lower respiratory tract and blood flow, while hospitals showed differences in changes in the microbial landscape. The microbiological situation in the ICU of the “red zone” was characterized by a decrease in the number of isolated strains of Enterobacterales and non-fermenting Gram-negative bacteria by the end of the pandemic, as well as a significant increase fungi in sputum. In hospitals, where there was an alternation of periods of work in the “red” and “green” zones, there was a decrease of Enterobacterales, an increase in non-fermenting Gram-negative bacteria and a fungi. Among the microflora isolated by bacteriological methods in patients with COVID-19, gram-negative bacteria and fungi predominated, mainly Klebsiella pneumonia, Acinetobacter baumanii and fungi of the Candida spp. A significant increase in the proportion of fungi in sputum was noted in ICU patients in infectious diseases hospitals during the pandemic period. An increase in the level of antibiotic resistance of the main pathogens of lower respiratory tract infections was revealed with the appearance of multi-resistant and extremely resistant strains of Klebsiella pneumoniae and Acinetobacter baumanii. Discussion. Changes in the microbial landscape may indirectly reflect the features of immune damage in patients with a new coronavirus infection COVID-19, which, combined with the severity of the disease and the characteristics of its therapy, led to an increase in complications in the form of a secondary bacterial infection. The reasons for the increase in HAI cases include: an increase in the number of patients with severe comorbidities in an artificial closed ecosystem - the “red zone”; features of the methods of treatment (glucocorticosteroids, genetically engineered biological products - IL-6 inhibitors, etc.); high frequency of unreasonable use of antibacterial drugs; increase in the duration ofuse of various invasive devices and mechanical ventilation; changing the structure and practice of staffing hospitals, increasing the number of inexperienced medical workers and volunteers; inadequate hand hygiene, use of unsuitable individual protection means with a lack of developed methods for their processing in the new conditions.   Conclusion. The results obtained indicate the importance of the work of a multidisciplinary with a microbiologist, epidemiologist, clinical pharmacologist in order to improve the quality of care for patients, especially in a difficult epidemiological situation. Surveillance over the spread of HAI pathogens should be attributed to the most progressive form of anti-epidemic activity. Microbiological monitoring and its results can serve as the basis for making managerial decisions to combat and prevent hospital infections. It is the main method for assessing the etiology, phenotype, mechanisms of resistance to antimicrobial drugs, allows you to identify epidemiological relationships between diseases, reasonably prescribe antibiotic therapy, and conduct targeted purchases of drugs (antibiotics) for the needs of this hospital.