Evaluation of antimicrobial activity of bacterial symbionts isolated from wild field cockroach from Saudi Arabia.

Drug-resistant pathogens form the main threat to global health during the current century. Annually, a lot of patients die in hospitals due to infection with one or more drug-resistant bacteria especially (MRSA). In the absence of new effective antimicrobial drugs, the number of deaths said to be increased. Searching for new antibiotics in our backyard form a part of scientist strategies to solve such serious health problem. Insects consider one of such interesting sources of the new era of antimicrobial drugs. Cockroaches as an example can live and adapt in a polluted area for a long time, so through this work field cockroach, was collected from two semi-wild areas around Riyadh, Saudi Arabia for isolation of gut bacteria searching for new antimicrobial agents. Three species of bacteria were identified from field cockroach gut: , and . The three species were isolated, purified, and tested for their antimicrobial activity against four drug-resistant pathogens (three bacteria: (ATCC25566), (MRSA) (Clinical strain), and (RCMB 017(1) ATCC ® 25175™) and one fungus: (RCMB005003(1) ATCC® 10231™)). The results show no antimicrobial activity of and very good activity and gives very effective activity against while is effective against MRSA and . None of the gut isolated bacteria show any activity against . Such results revealed that the metabolites of these bacteria could be used as substitutes to the already used antibiotics to overcome the problem of multidrug-resistant human pathogens.