Molecular identification of Staphylococcus sp. isolated from catfish (Clarias sp.) and its antibacterial activities

Abstract

In aquaculture, probiotic bacteria play an important role for increasing the fish and shrimp production due to its beneficial roles. Recently, many researchers have been exploring the sources for isolating the probiotic candidates. The objectives of this study were to identify staphylococcus bacteria isolated from catfish and to assays its antibacterial activity against several photogenic bacteria (Salmonella typhimurium, Aeromonas hydrophila, Escherichia coli and Bacilus cereus). The probiotic candidate was isolated from catfish (Clarias sp) by using de Mann Rogosa Sharpe (MRS) agar with the addition of 1% CaCO3. The colony with clear zone around it, would be further analyzed by using gram and catalase analysis. Further analysis was applied to bacteria with gram positive and catalase positive. This initial analysis indicated that the bacteria was not belong to lactobacillus. Hence, with this found, we further investigated this species by using 16s rDNA analysis. The result revealed that the isolate was not belong to lactobacillus. It is Staphylococcus warneri with 99.9% similar with Staphylococcus warneri ATCC 27836. The antibacterial activity analysis showed that crude extracellular compounds of S. warneri was not broad spectrum antibacterial.