Bacterial Opportunist Pathogens in ICU Patients and COVID-19 Pandemic

ABSTRACT

Introduction. The COVID-19 infection caused by SARS-CoV-2 is often severe and can lead to fatal outcomes. It is known that the main route of transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is airborne. Studies revealed that up to 25% of subjects from at-risk groups who have been affected by severe viral respiratory infections acquired secondary bacterial infections. These individuals have been reported to have superinfections and co-infections with SARS-CoV-2. Numerous opportunistic infections have been identified in patients with COVID-19, including the major bacterial pathogens responsible for healthcare-associated infections. The prevalence, frequency, and characteristics of bacterial agents isolated in patients during the COVID-19 pandemic are poorly understood and are considered to be a significant gap in knowledge. Therefore, it seemed appropriate to perform a comparative analysis of changes in the structure of bacterial etiological agents in patients hospitalized in intensive care units before and during the COVID-19 pandemic. Purpose. To review research and to study the structure of opportunistic bacterial agents isolated in hospitalized patients and to evaluate the impact of the COVID-19 pandemic impact on changes in incidence and characteristics of the main opportunistic infectious agents compared to the same period before the pandemic. Materials and methods. Bacteria were isolated and identified by conventional bacteriological methods using a variety of biochemical series, test systems for identification, as well as with the use of an automatic hemocultivator, a microbiological analyzer, and a mass spectrometer. The analysis includes data from the WHONET database of the centralized microbiological laboratory of the city of Minsk regarding the test results of blood and respiratory samples from adult patients hospitalized in intensive care units. A comparative analysis of the structure of etiological agents was carried out quarterly for two equal time periods. It's important to note that any bacteria detected from sources other than the respiratory tract or bloodstream was excluded from this data. In addition, all the data received from the intensive care units (ICUs) were analyzed apart from data obtained in other units. Results. The results of respiratory and blood samples of 52,530 patients have been analyzed. A comparative analysis of the structure of microorganisms isolated from 33,539 samples (63.8%, CI95% 63.6–64.0) was performed. In addition, isolates classified as of opportunistic bacterial pathogens were identified in samples of 20,053 patients (59.8%, CI95% 59.5–61.1). It was found that during the COVID-19 pandemic there was a 2.6–fold increase in the number of patients with blood samples tested and a 1.8–fold increase in the number of patients with respiratory specimens tested. The most frequent isolate from both blood samples (pre-pandemic 20.2% (CI95% 19.0–21.4) and 19.9% (CI95% 19.3–20.5) during the pandemic) and respiratory specimens (pre-pandemic 39.0% (CI95% 38.0–40.0) and 40.6% (CI95% 39.9–41.3) during the pandemic) was K. pneumoniae. At the same time, the structure of bacterial agents was modified due to increasing prevalence of non-fermenting gram-negative bacteria. Thus, the frequency of A. baumannii isolated from blood samples increased by 1.8 times, and those isolated from respiratory specimens by 1.3 times. For K. pneumoniae an increase in resistance frequency against penicillins, 3rd-and 4th-generation cephalosporins, carbapenems, fluoroquinolones, colistin, tetracycline, and tigecycline was established;for A. baumannii isolated from blood samples an increase in resistance frequency against gentamicin, tobramycin, and colistin was revealed, and for those from respiratory specimens an increase in resistance frequency against imipenem, meropenem, and tetracycline was revealed during the pandemic. Conclusion. An increase in frequency of isolation of gram-negative pathogens was established. It was indirectly confirmed that co-infection a d or superinfection with K. pneumoniae and A. baumannii and other opportunistic bacteria characterized by multiple resistance to antibacterial drugs, could increase the risks of severe course of underlying disease and lead to lethal outcomes. Prevention of secondary bacterial infections in ICU patients, including those diagnosed with COVID-19, requires an improvement in prevention programs, infection control practices and antibiotic therapy management systems. © 2022, Professionalnye Izdaniya. All rights reserved.