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Abstract:
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Pathogenic microorganisms such as Bacillus cereus, Listeria
Monocytogenes and Staphylococcus sp have caused serious diseases, and
consequently contributed to considerable economic loss in the food and
agricultural industries. Antibiotics have been practically used to treat these
pathogens since penicillin G was discovered more than half a century ago. Many
different types of antibiotics have been discovered or synthesized to control
pathogenic microorganisms. Repetitive use and misuse of antibiotics by the
agricultural and pharmaceutical industries have caused the emergence of
multidrug-resistant microorganisms, even to the strongest antibiotics currently
available; therefore, the rapid development of more effective antimicrobial
compounds is required to keep pace with demand.
Bacteria were isolated from marine water and sediment samples collected
from various locations off the coast of Cochin and salt pans of Tuticorin using
pour plate technique. One hundred and twelve isolates were obtained. Seventeen
isolates exhibiting antimicrobial activity were segregated after primary screening.
The secondary screening which was aimed at selection of bacteria that produce
proteinaceous inhibitory compounds, helped to select five strains viz. BTFK101,
BTHT8, BTKM4, BTEK16 and BTSB22.
The five isolates inhibited the growth of six Gram positive test organisms
viz. B. cereus, B. circulans, B. coagulans, B. pumilus, Staphylococcus aureus and
Clostridium perfringens. After quantitative estimation of the bacteriocin
production, the two strains BTFK101 and BTHT8 were selected for further study. |