OBJECTIVE  To analyze the epidemic characteristics of common pathogens for upper respiratory tract infections (URTI) and the drug resistance of Mycoplasma pneumonia (MP) before and after the novel coronavirus (SARS CoV-2) epidemic.

METHODS  The study focused on individuals who underwent SARS-CoV-2 nucleic acid testing and patients with URTI at the First Affiliated Hospital of Hunan University of Chinese Medicine from Jun. 2022 to Dec. 2023. We analyzed the differences in the proportion of positive results of respiratory pathogens among the months, seasons, genders and age groups, as well as the situation of mixed infections. Sanger sequencing was performed on throat swab samples from MP-positive patients to analyze the mutation status of MP resistance sites.

RESULTS  In Dec. 2022, the percentage of samples resulted positive for SARS-CoV-2 nucleic acid test increased rapidly and then decreased, with its peak of 55.33% in May 2023. In contrast, the percentage of samples resulted positive for six respiratory pathogens dropped to its lowest peak (12.07%) in Jan. 2023, then rapidly increased, and again dropped to the second lowest peak (38.58%) in Jun. 2023. The percentages of samples with positive SARS-CoV-2 and six respiratory pathogens showed statistically significant differences in different months and seasons (all P < 0.05); The age groups with the highest proportion for human rhinovirus (hRV), MP, adenovirus (ADV), influenza A virus (IVA) and respiratory syncytial virus (RSV) were infancy (24.76%), adolescence (35.07%), childhood (19.05%), adulthood (15.22%) and infancy (19.42%), respectively; the differences in proportions among different age groups were statistically significant (all P < 0.001). Among the 6 types of respiratory tract pathogens, the percentage of results with mixed infection was 17.83%, and the top six ranked from high to low were: hRV+MP(19.92%), hRV+ADV(16.53%), hRV+RSV(13.94%), MP+ADV(9.96%), ADV+IVA(7.77%) and hRV+IVA (6.18%). From the results of MP resistance gene sequencing, 84.85% of patients carried mutation sites for resistance to macrolide antibiotics, all of which were 23S rRNA V region A2063 G point mutations.

CONCLUSIONS  The upward turning points of SARS-CoV-2 infection are accompanied by the downward turning points of other respiratory pathogen infections simultaneously. Different pathogens have their own characteristics on seasonal pattern and age distribution, and the current prevalent MP strains with 23S rRNA V region A2063 G point mutations are mostly macrolide resistant.