Work

Bacterial colonization of the respiratory tract in COVID-19 patients: potential source of bacterial infection

Year: 2026

Type: article

Abstract: BACKGROUND: Secondary bacterial infections of the respiratory system are one of the biggest medical concerns in patients undergoing hospitalization with a diagnosis of COVID-19. Opportunistic upper respiratory tract bacterial colonization or carriage typically precedes the majority of lower respiratory tract infections and pneumonia. Few studies have examined the relationship between the SARS-CoV-2 virus and bacterial colonization in COVID-19 patients. AIM: This study looked into the link between COVID-19 patients who have SARS-CoV-2 illness and respiratory system bacterial colonization and how this colonization could impact on COVID-19 clinical presentation. METHODS: This research thus examines this relationship by conducting an analytical, cross-sectional study with 210 COVID-19 patients. The patients are categorized into mild and moderate-to-severe cases, which will be compared with 50 non-COVID-19 controls. All participants provided sputum samples that were subjected to microbiological culture analysis. To identify specific microbes, a VITEK Compact automatic microbiology analyzer was employed. RESULT: The findings of the research highlighted that, as the severity of COVID-19 infection increased, significant changes in bacterial colonization patterns emerged. A normal oral flora was found to be present in the control group, while a notable increase in pathogenic bacteria was evident in those with moderate-severe COVID-19. Furthermore, severe cases presented with Gram-positive bacteria, particularly Staphylococcus aureus. Additionally, Gram-negative bacteria (i.e., Klebsiella pneumoniae, Pseudomonas aeruginosa, and Haemophilus influenzae) were commonly identified in moderate-severe cases, indicating more extensive bacterial colonization. CONCLUSION: The need to develop more comprehensive approaches to diagnosing COVID-19 and creating targeted treatment plans is highlighted through the increasing presence of Gram-negative bacteria and polymicrobial colonization in COVID-19 cases at admission. Thus, this research highlights the importance of monitoring bacterial colonization in the upper respiratory tracts of individuals diagnosed with COVID-19. CLINICAL TRIAL NUMBER: Not applicable

Source: BMC Infectious Diseases

DOI: 10.1186/s12879-026-12579-1