Abstract
Forty five strains of marine bacteria which showed inhibitory activities against bacterial swarming were isolated from larval black tiger shrimp (Penaeus monodon), brine shrimp (Artemia salina) nauplii and rearing seawater in Thailand. These marine bacteria were examined by a double-layer plate method for their growthinhibiting abilities against 50 strains of vibrios isolated from similar sources. As a result, 27 strains among 45 marine bacteria examined inhibited 32 to 94% of the vibrios tested. These Vibrio-inhibiting strains also exhibited inhibitory activities against 52 to 96% of the reference strains of 27 species of Vibrio including fish and shellfish pathogens. The inhibition was exhibited bactericidally, and antibiotics were produced extracellularly and inactivated by heat treatment at 70°C for 30 min. All the 27 strains of antibiotic producers were identified as Alteromonas-like organisms based on their taxonomical characteristics including G + C values of DNA (42.4-45.3 mol %).
