Classical Identification, 16S rDNA Sequencing, and Molecular Characterization of Bacillus species from Convenience Foods

Abstract

Identification of microorganisms is central to the study of microbiology at all levels of research. The methods employed are also important. It is however very pertinent that scientists the world over continuously improve on the method of microbial identification for greater efficiency. A study was conducted to isolate and identify Bacillus species from some ready-to-eat (RTE)/convenience food samples. The Bacillus species isolated were identified by using the classical method. The same isolates were further identified via use of the 16SrDNA sequencing method.The classical method identified all bacilli isolates as members of a precise species in the genus Bacillus, but with discrepancies observed in 3 out of 9 identified cases (33.3%) when comparison was made with PCR/sequencing method. PCR/sequencing method provided results which were in accordance with both classical and genotypic identification in more than 70% of cases.This study emphasized the presumptive nature of classical methods in identifying Bacillus species/strains, without further recourse to the use of more sensitive and molecular methods. Identities from the PCR method hold greatest sway and are regarded as most reliable as it involves the analysis of genetic sequences of this group of microorganisms.