Antibiotic susceptibility of Bacillus spp. isolated from shrimp (Penaeus monodon) culture ponds

About 30 Bacillus isolates from various sources like shrimp intestine, pond water and pond sediment were assayed for susceptibility to 16 antibiotics, which included cell wall synthesis inhibitors, protein synthesis inhibitors and nucleic acid synthesis inhibitors. Most of the isolates were more sensitive against protein synthesis inhibitors than nucleic acid synthesis inhibitors. Present study showed that all the Bacillus isolates were sensitive to tetracycline and chloramphenicol, two commonly used antibiotics in shrimp hatcheries and culture systems. This indicates that use of certain antibiotics would adversely affect these types of beneficial bacteria in shrimp aquaculture systems.