Increasing drug resistance among microbial pathogens threatens public health and creates a need for new antibiotics. Microbes have been an important source, but increasing rediscovery rates � among other factors � have led to diminished exploration of this source3. Interspecies interactions, especially those that mimic natural ones, can reveal new antibiotics that previous studies missed2. Several actinobacterial strains isolated from plant roots and soil were cultured in pairs to influence secondary metabolism and tested with indicator strains. Pairs were cultivated on R2YE, ISP2 and TSA solid medium for seven days (30 �C). Antibiotic production and other phenotypes were analyzed with soft-LB-agar overlays inoculated with an indicator strain and incubated again overnight. Activity was analyzed by visualization of inhibition halos. Other developmental changes such as induced/inhibited sporulation and inhibited growth were also noted. One promising interaction was chosen for the follow up study: the Krasilnikovia sp. T082 and Streptomyces sp. SPB78 pair, which triggers antibiotic production by T082 against a multi-resistant strain (Amycolaptosis sp. AA4). This activity was also observed in liquid medium (TSB). It was shown that SPB78 cell-free supernatant also triggers this activity through the production of very polar small molecules. The active molecule and method of induction are being investigated.

Actinobacterial interaction triggers antibiotic production against a multidrug resistant strain

248th National Meeting (2014)

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