Retrospective Analysis of Antibiotic Therapy and Sensitivity to Antifungals of Fungi of the Genus Candida, Secreted from Patients with Viral-Bacterial Pneumonia Associated with COVID-19

Abstract

The appointment of antibacterial agents for the treatment of pneumonia that develops with COVID-19 is one of the treatment regimens. Antibacterial agents are prescribed only in the case of presence of confirmed bacterial co-infection, but can be appointed empirically. This approach promotes the development of antibiotic resistance of opportunistic and saprophytic microflora of almost all habitats, including the oropharynx that can lead to dysbiotic lesions with activation of fungal flora. The aim of the study was to analyze the composition of the oropharyngeal microbiome of patients with viral and bacterial pneumonia who took antibiotics, as well as the sensitivity of fungi of the genus Candida to antifungal drugs for effective treatment of the underlying disease. Methods. The results of bacteriological examination of 113 inpatients treated with a diagnosis of COVID-19 were analyzed. Microbiological examination of oropharyngeal swabs was performed by the classical bacteriological method with dosed seeding of suspended material on differential diagnostic media (in particular Saburo medium was used for selection of fungi of the genus Candida) and genus identification by morphological, cultural, biochemical properties. Results. PCR tests were performed for all patients in the clinical trial to confirm the diagnosis of viral and bacterial pneumonia. According to the results of bacteriological examination, fungi of the genus Candida were found in 52 (46.0%) patients with pneumonia associated with COVID-19. The analysis of prescriptions showed that only 14 (26.9%) patients were treated with one antibiotic, two antibiotics were prescribed to 31 (59.6%) patients, and three – 7 (13.5%). In the structure of antibiotic therapy, the lion’s share were cephalosporins of the third generation (ceftriaxone, hepacef) – 33 (63.5%), and macrolides (azithromycin) – 16 (30.8%) patients. In the structure of the oropharyngeal microbiome, according to the results of bacteriological research, fungi of the genus Candida significantly prevailed, which were found in 52 (46.0%), and in 29 patients (25.7%) S. pneumoniae was found. The sensitivity of fungi of the genus Candida to antifungal agents was analyzed, the maximum number of resistant strains was detected to nystatin and amphotericin – 38.5% and 26.9%, with only 8 (15.3%) fungi of the genus Candida sensitive to nystatin. Conclusions. All patients with viral-bacterial pneumonia associated with COVID-19 received antibiotic therapy, the lion’s share were third-generation cephalosporins (63.5%), and macrolides – (30.8%). According to the results of bacteriological examination of the oropharyngeal microbiome after antibiotic therapy, fungi of the genus Candida predominated (46.0%), followed by S. pneumoniae (25.7 %). Isolated strains of fungi of the genus Candida showed resistance to nystatin (38.5%) and amphotericin (26.9%). Antifungal agents of the imidazole subgroup have shown high efficiency and a low percentage of resistant strains, which allows us to recommend them for the treatment of complications of COVID-19 caused by fungi of the genus Candida.