Optimizing Small World Initiative service learning by focusing on antibiotics-producing actinomycetes from soil

Small World Initiative and Tiny Earth are popular citizen science programs that are implemented worldwide in response to the global antibiotic resistance crisis. When starting up the program in Albacete (Spain), we noted that rates of isolated antibiotic-producing bacteria are generally low. To make the activity more stimulating for participating students, we modified the protocol to obtain more positive results by focusing on isolation of actinomycetes, the main producers of most clinically used antibiotics. Adaptations involved redesigning culture media, incubation times and temperatures, and modification of the ESKAPE antibiosis experiment by employing an agar-transplantation step. Of 390 bacterial isolates tested, almost 6% tested positive in antibiosis experiments and DNA sequence analysis confirmed that all positives are actinomycetes, demonstrating that our protocol is efficient toward isolating antibiotic-producing actinomycetes from soil. Evaluation forms filled by participating students indicated that the program was received very positively and that our modifications contribute to make this educational program more stimulating and efficient.