RESUMEN
Nocardiosis is an acute or suppurative chronic disease caused by an aerobic, gram-positive, weakly acid-fast and soil-borne filamentous and organism. Nocardia asteroides which is the dangerous and most frequently pathogen, infects humans through the respiratory tract. The bacterium is primarily an opportunistic pathogen that causes the infection in patients with underlying immunodeficiencies. The main purpose of the study was to detect antibody titre against Nocardia in all study groups, using indirect immunofluorescent assay [IFA]. Correlation between the antibody titre against Nocardia with age, sex, occupation, and chronic pulmonary infection and corticosteroid therapy patients was also investigated. The present investigation is a Cross-Sectional study conducted on a population consisted of 300 subjects including 200 hospitalized individuals patients, nurses and healthcare workers from Imam Khomeini hospital, and 100 health adult blood donors. None of the patients had already been diagnosed to be affected by Nocardia. Our results demonstrated four patients suffering from different infections, including TB, mycetoma, chronic pulmonary and chronic obstructive pulmonary diseases were IFA positive. None of the high risk hospital personnel, who were working in close proximity to the areas infected with Nocardia, were found to be IFA positive. Meanwhile there was no positive result in a group of patients [n=34] who were under corticosteroid therapy. Finally, considering the small sample size of the IFA positive cases no significant association between the IFA results and age, sex, occupation and clinical conditions of the subjects could be established