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1.
Russian Journal of Infection and Immunity ; 12(3):563-568, 2022.
Article in Russian | EMBASE | ID: covidwho-1969869

ABSTRACT

Multidrug-resistant K. pneumoniae bacterial strains producing extended range of beta-lactamases or carbapenemases are of serious clinical concern. The aim of the study was to determine the resistance factors of K. pneumoniae strains isolated from the lower respiratory tract of patients diagnosed with community-acquired pneumonia during the COVID-19 pandemic. Materials and methods. The study of resistance to antimicrobial drugs included 138 strains of K. pneumoniae isolated from the sputum of patients treated in infectious diseases monohospitals in the city of Tyumen and the Tyumen region within the period from May 2020 to June 2021. Among the strains examined, 51.4% of them were isolated from SARS-CoV-2 positive patients. The presence of resistance genes was determined by PCR in 71 strains of K. pneumoniae (34 strains from COVID-19-positive and 37 strains from COVID-19-negative patients). Identification of isolated bacterial strains was carried out according to the protein spectra by using a desktop time-of-flight mass spectrometer with matrix laser desorption MALDI-TOF MS (Bruker, Germany). The belonging of the strains to the hypermucoid phenotype was determined using the string test. Sensitivity to antimicrobial drugs was assessed in the disk diffusion method on Muller-Hinton medium. The sensitivity of culture strains to bacteriophage preparations was determined by the drop method (spot-test). In the study, we used “Polyvalent Sextaphage Pyobacteriophage” and “Purified Polyvalent Klebsiella Bacteriophage”, JSC NPO Microgen, Russia. Detection of resistance genes to beta-lactam antibiotics by real-time PCR was carried out using the BakRezista kit (OOO DNA-technology, Russia). The results of the study evidence that K. pneumoniae bacteria isolated from COVID-19-positive and COVID-19-negative patients diagnosed with community-acquired pneumonia displayed a high resistance to antimicrobial drugs and commercial phage-containing drugs. Resistance of K. pneumoniae strains was recorded from 50% (to aminoglycosides and carbapenems) to 90% (to inhibitor-protected penicillins). Sensitivity to bacteriophages was noted on average in no more than 20% of strains. It is important to emphasize that strains isolated from COVID-19-positive patients more often showed a hypermucoid phenotype, suggesting a high bacterial virulence, and also showed greater resistance to all groups of antibacterial drugs examined in the study, which is confirmed by the presence of resistance genes of the ESBL group and carbapenemase. The results of the study suggest that the high level of resistance of K. pneumoniae strains isolated from COVID-19-positive patients is associated with immunosuppression provoked by the SARS-CoV-2 virus, which contributes to their colonization by more virulent strains.

2.
Zhurnal Mikrobiologii Epidemiologii i Immunobiologii ; 98(5):528-537, 2021.
Article in Russian | Scopus | ID: covidwho-1567021

ABSTRACT

Introduction. Many aspects of the pathogenesis and pathomorphology of pneumonia associated with novel coronavirus require a comprehensive study using modern diagnostic methods. The aim of the study was to study the microbiota of the lower respiratory tract in community-acquired pneumonia associated with SARS-CoV-2, to assess the antibiotic and phage resistance of circulating strains of microorganisms. Materials and methods. The analysis of biosamples from 486 patients undergoing inpatient treatment in five mono-hospitals in Tyumen and Tyumen region with a diagnosis of moderate and severe community-acquired pneumonia was carried out. In almost 90% of cases patients received oxygen therapy, about 8% of patients were connected to ventilators. The inoculation of the cultures with clinical samples was carried out for six months (from April to October 2020). The isolated bacterial strains were identified by mass spectrometry. The resistance to antimicrobial drugs and bacteriophages was assessed for identified isolated. Results. Gram-positive cocci, mainly opportunistic microorganisms of the genus Streptococcus and Candida fungi predominated in the microbiota of the lower respiratory tract of patients diagnosed with community-acquired pneumonia associated with SARS-CoV-2. At the same time, bacteria of the Enterobacteriaceae family and nonfermenting gram-negative bacteria were less common compared to patients without coronavirus infection. In the structure of pathogens, the leading position was occupied by the bacteria K. pneumoniae and Acinetobacter spp. The analysis of the sensitivity of microorganisms to antimicrobial drugs showed the highest resistance rates in strains of Acinetobacter spp., Enterococcus spp., Coagulase-negative Staphylococcus. It has been established that in the group of patients with community-acquired pneumonia associated with SARS-CoV-2, the risk of infection with Streptococcus spp. with high level of antibiotic resistance was 1.5 times higher, and taking into account the 95% confidence interval, the value of this indicator ranged from 1.1 to 2.1 times. Conclusion. The data obtained indicate that the microbiota of the lower respiratory tract in community-acquired pneumonia associated with SARS-CoV-2 is represented mainly by bacteria of the genus Streptococcus, which have a high level of resistance to antimicrobial drugs. © 2021, Central Research Institute for Epidemiology. All rights reserved.

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