Abstract:
Multi-drug resistant pathogens are a leading cause of human morbidity and mortality
all over the world. We isolated actinomycetes from the soils of Menengai crater and
characterized selected actinomycetes using classical and molecular techniques.
Actinomycetes were isolated using starch casein (SC), Luria Bertani (M1) and starch
nitrate (SN) agar media. Screening for antibiotic activity was carried out by primary
screening using perpendicular method and secondary screening using agar plug
technique against selected bacterial and fungal pathogens. The best actinomycetes based
on size of inhibition and broad spectrum of activity coded PAN 25, PAN 41, PAN 75
and PAN 110 were selected for further bioassay. The selected actinomycetes were
characterized using molecular technique that involved extraction of 16S rRNA gene,
PCR and phylogenetic studies. Data was analyzed using Statistical Package of Social
Sciences (SPSS) software. There was a significant difference in the number of
actinomycetes isolated using the three types of media (F=3.315 P=0.04218). There was
no significant difference in the zones of inhibition between the isolates PAN 25, PAN 41,
PAN 75 and PAN 110 (F=0.8928 P=0.5431). Molecular characterization revealed that
isolate PAN 25 had 99% similarity with Streptomyces variabilis, isolate PAN 41 (S.
indiaensis), isolatePAN 75 (S. luteogriseus strain ZG728) and isolate PAN 110 (S. acrimycini
strain K30). Menengai crater had actinomycetes that inhibited growth of the selected
actinomycetes. Large scale production of antibiotics from the selected actinomycetes
should be carried out.
