Evaluation of Drug Resistance and the Presence of Important Resistance Genes in Clinical and Environmental Hospital Isolates of Nocardia

Background & Aims: This study aimed to investigate drug resistance and the presence of crucial resistance genes in clinical and environmental hospital isolates of Nocardia.Materials and Methods: Clinical and environmental samples were isolated and identified from hospitals in Tehran, Iran.Antibiotic susceptibility testing was performed according to Clinical and Laboratory Standards Institute (CLSI) guidelines, and the presence of resistance genes was examined by polymerase chain reaction (PCR).This study obtained 79 isolates from environmental samples, including 16 species, after phenotypic and molecular testing.N. cyriacigeorgica was the most common species in environmental and clinical specimens.Results: All isolates were highly susceptible to linezolid (LZD), amikacin, and cotrimoxazole.The highest sensitivity was observed with LZD, and the lowest with clarithromycin.Conclusion: Determining antimicrobial sensitivity and the presence of resistance genes is vital to improving treatment effectiveness.LZD, amikacin, and cotrimoxazole are recommended for the treatment of nocardial infections.