Isolation and Characterization of Medically Important Aerobic Actinomycetes in Soil of Iran (2006 - 2007)

Abstract

The aerobic actinomycetes are a large group of soil-inhabiting bacteria that occur worldwide. Some of them are the main cause of two important diseases, nocardiosis and actinomycetoma. To identify the prevalence and geographic distribution of aerobic actinomycetes in soil of Qazvin province, a study was carried out during 2006-2007. In this study, the incidence and diversity of medically important aerobic actinomycetes was determined in 300 soil samples of different parts of Qazvin. The suspensions of superficial soil samples were prepared by adding of normal saline, streptomycin and chloramphenicol and the supernatants were cultured on brain-heart infusion agar and Sabouraud's dextrose agar contain cycloheximide. The isolated microorganisms were examined by Gram and acid-fast stains and were identified biochemically and morphologically. Of 96 aerobic actinomycetes isolates identified, Actinomadura madurae and Streptomyces somaliensis were the most frequently isolated species each representing 19.8% of isolates, followed by Nocardia asteroides (15.6%), N. otitidiscaviarum (9.4%), N. brasiliensis (7.3%), A. peletieri, S. griseus, and Nocardia spp. (each 5.2%), and N. transvalensis, Nocardiopsis dassonvillei, Actinomadura spp. and Streptomyces spp. (each 3.1%). To the best of our knowledge, this is the first report on epidemiological investigation of medically important aerobic actinomycetes in soil samples from Iran. In recent years, mycetoma and nocardiosis have been increasingly reported in Iran. The results showed that medically important actinomycetes occur in the environment of Iran and soil could be potential source of actinomycotic infections.

Isolation and screening of antibiotic producing actinomycetes from soils in Gondar town, North West Ethiopia

“…During the study, 15 soil samples were collected aseptically from 5 sites at different depth (5,8 and 11 cm) of the soil using standard methods [15,16] . The collected samples were transferred to research laboratory of microbiology, Department of Biology in Tewodros campus where the entire research work was carried out.…”

“…After incubation, actinomycetes on the plates were identified based on color, dryness, rough, convex colony. The identified colonies were purified by repeated streak plate method [15,18] . After isolation of the pure colonies, each colony was further identified on the basis of its earthy like smell, colonial morphology, colour of hyphae and the presence or absence of aerial and substrate mycelium.…”

Comparison of Various Methods for Isolation of Nocardia from Soil

“…Despite greater clarity and earlier appearance of Nocardia colonies on SDA medium (See Figure 3D) than the PA medium, the low numbers of colonies were isolated on this media. In a study conducted by Aghamirian et al 96 aerobic actinomycetes were isolated from 300 the soil samples of Qazvin province on brain-heart infusion agar and Sabouraud dextrose agar (SDA) [26]. In these cases, white and creamcolored growth was observed on the paraffin-coated rod above the surface of the carbon-free broth (See Figure 3A).…”

Exploration of Antimicrobial Property of Isolated Fungal Cultures from Soil of Northern Region of India

“…The identified colonies were purified by repeated streak plate method [11,12]. After isolation of the pure colonies, each colony was further identified on the basis of its morphological characteristic odour, colony morphology, colour of hyphae and the presence or absence of aerial and substrate mycelium.…”