Abstract

Random amplified polymorphic DNA (RAPD) assay and antimicrobial activities were used for the detection of genetic variations of antimicrobial isolates from the Kingdom Saudi of Arabia. Soil samples were collected from El-Madina El-Monawara, El–Taif, El-Jouf and El-Dammam for bacterial isolation. Bacterial isolates were evaluated for their antimicrobial activities against pathogenic fungi which cause dermatological diseases; Acremonium sp., Microsporium gypseum, Microsporium gallinae, Exserohilum sp., Trichphyton sp. and Aspergillus niger. Results indicate that all the bacterial isolates showed different levels of antagonistic activities against the pathogenic fungi. Esherichia coli M2, Bacillus megaterium M3 and Bacillus subtilis M10 showed strong effect against all the tested pathogenic fungi. B. subtilis J1 isolate showed strong effect against the two pathogenic fungi M. gallinae and Exserohilum sp. Nine strains were tested for their antibiotic response. The results show that different antibiotic response was found. RAPD fingerprinting technique was applied to study the genetic diversity among the tested strains. Results indicate that there was a significant genomic diversity among the B. subtilis strains and this diversity was highly correlated with habitats and the antagonistic effect of the studied strains.

Key words: Random amplified polymorphic DNA-polymerase chain reaction (RAPD-PCR), bacterial isolates, pathogenic fungi, Kingdom of Saudi Arabia.