Identification of PST 10 bacterial isolate with ?-hemolysis characteristic isolated from pig's tonsil

Abstract

Background: Pig's tonsil is one of the entry points and habitat of commensal microbes and pathogenic bacteria, both Gram-positive and Gram-negative bacteria. Recently, a human meningitis outbreak has reported at Sibang Kaja, Badung-Bali. The cause of this outbreak has been suspected due to the consumption of pig-derived foods. The outbreak was known to be caused by Gram-positive ?-hemolytic bacteria. Based on this fact, PST 10 bacterial isolate with similar characteristics to the outbreak caused interesting identification.Method: PST 10 isolate was cultivated in a specific medium 5% defibrinated sheep blood agar plate. Subsequently, Gram staining, catalase, oxidase, salt tolerance (6% NaCl), and hemolysis test. This presumptive isolation was then conventionally identified by KIT API 20 STREP and molecularly using the 16S rRNA gene.Results: PST 10 isolate was identified as Enterococcus faecium using KIT API 20 STREP. Furthermore, the 16S rRNA gene sequencing analysis shows that the isolate has 99.6% similarities with Enterococcus faecalis (MG543832). The isolate shares the same clade in the phylogenetic tree analysis with a 100% bootstrap value.Conclusion: The high sensitivity in molecular identification mainly to distinguish close species using phenotypic approaches, PST 10 isolate was concluded as Enterococcus faecalis.