Tag Archives: PCR

Classical Identification, 16s Rdna Sequencing, And Molecular Characterization of Bacillus Species from Convenience Foods (Published)

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 16S rDNA 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 genotypical identification in more than 70% of cases. This study emphasized the presumptive nature of classical methods in identifying Bacillus species/strains, without additional 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.

Keywords: Bacillus, Classical, Convenience Foods, Identification, PCR


Pseudomonas aeruginosa is an aerobic Gram-negative bacterium which has emerged as one of the most problematic nosocomial pathogens. To characterizes P. aeruginosa strains that are widespread in patients in Hilla city,300 clinical and environment samples were collected from wounds, burn, ear, stool ,nose ,sputum and urinary tract infection taken from general hospitals of Hilla city. Methods for isolation and identifying P. aeruginosa based upon culture methods coupled with biochemical tests, were used in this study. The results show that, the selective medium (cetrimide agar) at 42˚C aerobically had highest recovery in the isolation of P. aeruginosa, they were produced greenish-yellow or blue pigment colonies, catalase and oxidase was positive whereas negative for methyl red, VogesProskauer and indole. A total of 34 amplified DNA fragmentsfrom 250 to 1500 bp)were observed using the 6 random primers,Amplification bands were exclusively revealed with four out of the six random primers (OPB-10,OPX-01,272,275) While( RAPD TYPING, 325) primers were failure to give amplification bands, and each of primer that successful giving amplification bands revealed different genetic patterns .

Conclusion:RAPD-PCR analysis proved to be of great value in designing a variety of molecular based epidemiological studies that focuses on the identification and characterization of P.aeuroginosa



Keywords: PCR, Pesudomonas aeruginosa, RAPD, nosocomial