CHARACTERISTICS OF RESPIRATORY TRACT BACTERIAL MICROFLORA DETECTED IN PATIENTS SUFFERING FROM COMMUNITY-ACQUIRED PNEUMONIA DURING CONTINUING SPREAD OF THE NEW CORONAVIRUS INFECTION IN KHABAROVSK CITY (DECEMBER 2020 - MARCH 2021)

Objective of the research - to specify respiratory tract bacterial microflora in patients suffering from community-acquired pneumonia (CAP) during initial and repeat examination. To determine local factors affecting microflora in the cohort examined. Materials and methods. Surveillance subject - 241 patients with CAP differed by their status and age who stayed in two healthcare facilities of the Khabarovsk city. Examination of respiratory smears was performed. Results. Indices of Gram-negative enterobacteria (30.8% [22.6-39.7%]) and Gram-negative nonfermentable bacteria (14.5% [8.6-21.7%]), isolated from patients hospitalized in healthcare institution No. 1 and mostly comprised of the elderly (aged over 61 years - 82.0%; 74.3-88.6%) with more severe disease state including patients at the ICU, were higher compared to data obtained from healthcare institution No. 2 (19.8% (13.4-27.0); 6.1% (2.7-10.8) respectively). Prevalent pathogen was Klebsiella pneumoniae - 13.6% (7.8-20.6) and 10.7% (6.0-16.5). Identification of Acinetobacter baumannii complex 6.4% (2.6-11.7) and 3.1% (0.8-6.7) - should be also noted. A high percentage of drug-resistant bacterial variants was observed and for Klebsiella pneumoniae totaled 66.7% (41.8-87.4) and 57.1% (32.2-80.2) at the healthcare institutions No. 1 and No. 2, respectively. A. baumannii complex drug resistant variants were found in 85.7% (52.7-99.97) at healthcare institution No. 1. All isolates of A. baumannii complex at the healthcare institution No. 2 were drug resistant. High prevalence of Candida spp. was revealed in both healthcare institutions reaching 54.5% (45.2-63.7) and 58.0% (49.5-66.3), respectively, with minimal detection rate of classic pathogens such as S. pneumoniae - 5.4% (2.0-10.4) and 5.3% (2.1-9.8) and H. influenzae - 3.6% (0.9-7.9) and 3.8% (1.2-7.7), respectively. Repeat examination of 122 patients conducted 7-10 days later showed diverse changes in microflora spectrum regardless of the healthcare institution that was manifested as loss or emergence of drug-resistant variants as well as simultaneous presence of different variants of the same pathogen. Conclusion. The results obtained evidence about complexity and variety of mechanisms underlying microorganism community formation during the course of infectious process in patients. Local factors influencing microflora characteristics of patients at the two healthcare institutions were revealed.

Automated summary

This study aimed to examine the respiratory tract bacterial microflora in patients with community-acquired pneumonia (CAP) and determine the local factors influencing the microflora. The results showed variations in the composition and antibiotic resistance of the microflora between different healthcare institutions and during different examination periods. Klebsiella pneumoniae and Acinetobacter baumannii complex were the dominant pathogens, and a high percentage of drug-resistant variants was observed. The microflora composition also underwent diverse changes over time.