Genetic relatedness of local Cronobacter sakazakii based on invasion gene ompA

Abstract

Cronobacter sakazakii is a foodborne pathogen, one of which due to the possession of invasion gene ompA. Ten C. sakazakii previously isolated from dried foods in Indonesia were found to own the ompA gene. This study aimed to evaluate the genetic relationship among these local isolates and their similarity with C. sakazakii references based on the ompA gene. DNA isolation was carried out using Chelex, the ompA gene was amplified with PCR followed by agarose gel electrophoresis and sequencing. The sequences were subjected to contig analysis using Bioedit software, and the results were analyzed for homology by the BLAST on NCBI website. The phylogenetic tree was constructed using MEGA v.6 with the maximum-likelihood algorithm and 1000 replication bootstrap. The result shows that C. sakazakii FWHb6 and FWHd16 were in one cluster with C. sakazakii ATCC 29544 known to invade the human intestine. In general, the ompA gene of the local isolates had a close genetic relationship with C. sakazakii references. This study suggests that local C. sakazakii possess similar invasion to other C. sakazakii. This finding can contribute to Cronobacter classification.