Table 1.
MIC values of a crude antimicrobial extract derived from Streptomyces sp. CMU-NKS-3.
| Test organism | MIC (mg mL−1) | ||
|---|---|---|---|
|
| |||
| Crude extract from Streptomyces sp. CMU-NKS-3 | Positive control | ||
|
| |||
| Streptomycin | Benomyl | ||
| Gram positive bacteriaa | |||
| Bacillus cereus1 | 1.22×10−3 | 0.02 | ND |
| Enterococcus faecalis ATCC 292172 | 0. 31 | 0.04 | ND |
| Micrococcus luteus3 | 1.22×10−3 | 2.44×10−3 | ND |
| Staphylococcus aureus ATCC 292134 | 2.44×10−3 | 4.88×10−3 | ND |
| Methicillin-resistant Staphylococcus aureus (MRSA)5 | — | 0.62 | ND |
| Gram negative bacteriab | |||
| Enterobacter aerogenes6 | 0.16 | 0.04 | ND |
| Escherichia coli ATCC 352187 | — | 0.08 | ND |
| Escherichia coli O157:H78 | — | 0.16 | ND |
| Klebsiella pneumoniae (ESBL+)9 | — | 0.04 | ND |
| Proteus mirabilis10 | 0.02 | 0.08 | ND |
| Proteus vulgaris11 | — | 0.02 | ND |
| Pseudomonas aeruginosa ATCC 2785912 | — | 0.08 | ND |
| Pseudomonas fluorescens13 | 0.04 | 2.50 | ND |
| Salmonella sp. Group D14 | — | 9.76×10−3 | ND |
| Salmonella typhae15 | — | 0.62 | ND |
| Serratia marcescens16 | — | 0.16 | ND |
| Yeastsc | |||
| Candida albicans17 | 6.10×10−4 | 0.31 | ND |
| Cryptococcus neoformans18 | 6.10×10−4 | 0.08 | ND |
| Filamentous fungid | |||
| Aspergillus flavus19 | 1.25 | ND | 0.31 |
| Colletotrichum musae20 | 0.62 | ND | 0.08 |
| Fusarium solani21 | 0.31 | ND | 0.08 |
| Rhizoctonia solani AG-222 | 0.16 | ND | 0.02 |
| Sclerotium solani23 | 0.16 | ND | 0.04 |
The initial stocks were kindly provided by the Central and Diagnostic Laboratory, Maharaj Nakorn Chiang Mai Hospital, Faculty of Medicine, Chiang Mai University, Thailand.
The filamentous fungi (phytopathogens) were taken from a culture collection at the Sustainable Development of Biological Resources Lab (SDBR), Department of Biology, Faculty of Science, Chiang Mai University.
Index numbers refer to the test organisms shown in Fig. 6. Not determined (ND) and no inhibition activity (—) were also observed, while methanol was used as a negative control for all tests. Initial concentrations of the crude extract and positive controls together with their dilution factors can be found in the Materials and Methods section. Tests were performed in triplicate, and no significant difference was observed in the results derived from triplicate experiments.