Features of the etiology of SARS-CoV-2–associated pneumonias in Primorsky territory
- Authors: Sokotun S.A.1, Mikhaylov A.O.1, Simakova A.I.1, Plekhova N.G.1, Beniova S.N.2, Chirkova Е.P.2, Savinov A.A.2, Belevich I.O.1
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Affiliations:
- Pacific State Medical University
- Regional Clinical Hospital № 2
- Issue: Vol 30, No 2 (2025)
- Pages: 106-115
- Section: Original study articles
- URL: https://journals.rcsi.science/1560-9529/article/view/334362
- DOI: https://doi.org/10.17816/EID646542
- EDN: https://elibrary.ru/NFGLOI
- ID: 334362
Cite item
Abstract
Background: Analysis of morbidity, including pneumonia, among patients with coronavirus disease is of clinical interest. Investigation of the microbial spectrum of sputum and its antibiotic susceptibility may inform treatment strategies, taking into account concomitant bacterial and/or fungal colonization.
Aim: The study aimed to perform an epidemiologic analysis of SARS-CoV-2 infection morbidity in Primorsky territory during 2021–2023, to conduct a comparative analysis of the etiologic structure of pneumonia in patients with COVID-19, and to assess antibiotic resistance of lower respiratory tract microbiota.
Methods: We conducted a retrospective cohort study based on archived medical records from Regional Clinical Hospital No. 2 (Vladivostok, Russia). The analysis included 6491 medical records of patients with confirmed COVID-19 who were hospitalized from 2021 to 2023. Bacteriological analysis of specimens was performed using differential diagnostic media. Isolated pathogens were identified, and antibiotic resistance was determined with an automated bacteriological analyzer (BD Phoenix™ M50).
Results: The total number of hospitalized patients with COVID-19 in Primorsky territory and the proportion of pneumonia among them peaked in 2021, with a subsequent marked decline by 2023. In 2021, pneumonias were predominantly of viral etiology, and a microbial pathogen was identified in only one-third of cases. Subsequently, in patients with laboratory-confirmed COVID-19, the frequency of bacterial superinfection increased, along with a rise in the proportion of opportunistic microorganisms (including Candida, Mycoplasma pneumoniae). By 2023, their proportion increased more than sixfold. The isolated bacteria were etiologically significant and belonged to the ESKAPE group. In most cases, they were detected as monocultures or in combination with yeast fungi. Analysis of sputum microbiota showed that gram-positive flora predominated until 2022, whereas by 2023, the gram-positive-to-gram-negative ratio equalized. The proportion of methicillin-resistant Staphylococcus aureus reached 52.7%, and strains resistant to most antibacterial agents reached 77.2%. Gram-positive microorganisms exhibited resistance to penicillin antibiotics and fluoroquinolones, whereas gram-negative microorganisms showed resistance to third-generation cephalosporins, fluoroquinolones, and carbapenems.
Conclusion: In 2021, sputum from patients with SARS-CoV-2–associated pneumonia was dominated by gram-positive flora, whereas by 2023, the proportion of gram-negative and opportunistic microorganisms increased. The most frequently isolated gram-positive microorganisms were commonly resistant to penicillins and fluoroquinolones, and gram-negative microorganisms were resistant to third-generation cephalosporins, fluoroquinolones, and carbapenems. Thus, the microbial spectrum of sputum in pneumonia among patients with COVID-19 in Primorsky territory has distinctive features that should be considered when selecting antibacterial therapy.
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##article.viewOnOriginalSite##About the authors
Svetlana A. Sokotun
Pacific State Medical University
Author for correspondence.
Email: sokotun.s@mail.ru
ORCID iD: 0000-0003-3807-3259
SPIN-code: 8744-2166
MD, Cand. Sci. (Medicine), Assistant Professor
Russian Federation, 2 Ostryakova ave, Vladivostok, 690002Aleksandr O. Mikhaylov
Pacific State Medical University
Email: mao1991@mail.ru
ORCID iD: 0000-0002-2719-3629
SPIN-code: 1469-9086
MD, Cand. Sci. (Medicine), Assistant Professor
Russian Federation, 2 Ostryakova ave, Vladivostok, 690002Anna I. Simakova
Pacific State Medical University
Email: anna-inf@yandex.ru
ORCID iD: 0000-0002-3334-4673
SPIN-code: 3563-7054
MD, Dr. Sci. (Medicine), Assistant Professor
Russian Federation, 2 Ostryakova ave, Vladivostok, 690002Natalia G. Plekhova
Pacific State Medical University
Email: pl_nat@hotmail.com
ORCID iD: 0000-0002-8701-7213
SPIN-code: 2685-9578
Dr. Sci. (Biology), Assistant Professor
Russian Federation, 2 Ostryakova ave, Vladivostok, 690002Svetlana N. Beniova
Regional Clinical Hospital № 2
Email: snbeniova@mail.ru
ORCID iD: 0000-0002-8099-1267
SPIN-code: 9715-7742
MD, Dr. Sci. (Medicine), Professor
Russian Federation, VladivostokЕlena P. Chirkova
Regional Clinical Hospital № 2
Email: chirkova_ep@kkb2.ru
ORCID iD: 0009-0008-1263-4322
SPIN-code: 4568-0711
Russian Federation, Vladivostok
Andrey A. Savinov
Regional Clinical Hospital № 2
Email: savinov.andrey28rus@mail.ru
ORCID iD: 0009-0001-9284-3296
Russian Federation, Vladivostok
Ivan O. Belevich
Pacific State Medical University
Email: belevich_1998@mail.ru
ORCID iD: 0009-0001-9480-2199
Russian Federation, 2 Ostryakova ave, Vladivostok, 690002
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