Hamadan University of Medical Sciences Avicenna Journal of Clinical Microbiology and Infection 2383-0298 12 2 2025 06 30 Prevalence of Erythromycin Resistance Genes in Gram-Positive and Gram-Negative Bacteria From Secondary Infections 61 66 10.34172/ajcmi.3605 EN Mohammadsaid Golabi https://orcid.org/0009-0006-5649-2149 Maryam Mohammadi-Sichani https://orcid.org/0000-0002-8716-8863 Sodabeh Rostami https://orcid.org/0000-0002-9281-0398 Journal Article 10.34172/ajcmi.3605 2025 01 30 2025 04 21 Background: Bacterial secondary infections in patients can exacerbate disease symptoms and significantly increase mortality rates. This study aimed to evaluate the prevalence of bacterial agents responsible for secondary infections in hospitalized patients and to identify the presence of erythromycin resistance genes (ermB, ermA, and mefA) in bacterial isolates. Methods: Samples from secondary infections were collected from hospitalized patients to determine the most prevalent bacterial pathogens and assess their resistance profiles using the polymerase chain reaction method. Results: The bacterial species most frequently associated with secondary infections were Escherichia coli (32.2%), Klebsiella pneumoniae (31.2%), Enterococcus faecalis (24.3%), and Acinetobacter baumannii (11.3%). Testing for antibiotic susceptibility indicated that most bacterial isolates were resistant to erythromycin and ciprofloxacin. Notably, the ermB gene was detected in 89.6% of the isolates, while ermA and mefA genes were absent in all bacterial isolates. Conclusion: These findings underscore the significant level of erythromycin resistance among pathogens responsible for secondary infections in hospitalized patients, with a predominant association with the ermB gene. This highlights the pressing need for improved antibiotic stewardship and the development of alternative therapeutic strategies to combat the growing threat of secondary bacterial infections in clinical settings.