In preliminary screening for actinomycetes, thirty soil samples collected from six caves in Changwat Kanchanaburi, Ratchaburi and Saraburi were used. The percentage of actinomycetes isolated from caves namely: Mungkorn-tong, Kao-lam, Sarika, Jom-pon, Kao-bin and Pothisat were 2.23, 3.92, 7.23, 0.16, 1.16 and 0.84 respectively. The net per cent of isolated actinomycetes was 3.81.
This article presents a study on the antibiotic-producing capability of Actinomycetes strain ST-13-2, utilizing the bioautograph technique to assess antibacterial activity. The findings revealed that the produced compounds are water-soluble basic antibiotics with a clear inhibitory effect against Staphylococcus aureus. Some of the substances exhibited more than one inhibition zone, and one of the zones had an Rf value equivalent to that of Cloxacillin (Rf = 0.26), indicating potential antimicrobial properties.
Further testing demonstrated that the antibiotic substances from this strain were capable of inhibiting the growth of Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Klebsiella pneumoniae, based on 30 clinical isolates obtained from hospitalized patients. The results showed that all bacterial strains were inhibited, except for Pseudomonas aeruginosa, which exhibited only partial susceptibility.
