Present article consists the in vitro antibacterial study
carried out using leaf extracts of Rhizophora mucronata L., a mangrove plant. Extracts were
screened for antibacterial activity against multi-drug resistant Vibrio harveyi and Vibrio
campbellii. The same were isolated from Lobster's larvae hatchery water. Antibiotic resistance
and sensitivity of the isolated Vibrio spp. were tested with Hi-Media antibiotic disc. Out of
total eight antibiotics discs used, V. harveyi was found highly resistant to ampicillin,
oxacillin, cephalothin, vancomycin, erythromycin, and clidamycin, while, it was sensitive towards
chloramphenicol (19 mm) and gentamycin (9 mm). Whereas, Vibrio campbellii was found highly
resistant to ampicillin, oxacillin, cephalothin, vancomycin, and erythromycin. Vibrio campbellii
was highly sensitive to chloramphenicol (20 mm), and moderately sensitive to clindamycin (9 mm),
and gentamycin (14 mm). Chloroform leaf extract of Rhizophora mucronata L. was found to be the
most active one against both Vibrio spp., while, hexane, ethyl acetate, and methanol extract
revealed moderate activity against both Vibrio spp. However, distilled water extract did not have
any activity. Chloromphenicol from the Hi-Media antibiotic and chloroform extract from Rhizophora
mucronota leaves can be used as a source of alternative compound to control the Vibrio spp. which
infects the Lobster's larvae.