Five tree species contained antibiotic-producing bacteria within their bark.

Soil is a common source for identifying antibiotic-producing bacteria; however, other ecosystems in nature may contain novel bacteria capable of producing antibiotics. Bark from seven tree species was collected as a new source to culture bacterial isolates that were screened against nine tester bacteria related to antibiotic resistant pathogens. Five of the seven tree species contained isolates that showed antibiotic production against at least one of the tester bacteria. Bark should be further explored as a possible source for bacteria that produce unknown antibiotics.