Document Type : Original Article


1 Corresponding author: Dr. Farag M. Saieb, Microbiology Laboratory, Department of Botany, Omar Almukhtar University, El-beida, Libya.

2 Microbiology Laboratory, Department of Chemical and Environmental Sciences, University of Limerick, Limerick, Ireland


Salmonella is a genus of the family Enterobacteriaceae. Members belonging to this family are characterised as Gram-negative, non-spore forminer, rod-shaped bacteria. Motility forms of these bacteria have peritrichous flagella. Many members of this family of bacteria are commonly located in the intestinal tract of both animals and humans as either pathogens or commensals. The aim of this study was to confirm the absence or presence of homoserine lactones for the purpose of quorum sensing. Homoserine lactones are single molecules that are expressed by the bacteria when a critical cell mass has been reached. It allows the bacteria to coordinate their activities and survive adverse conditions. Bacterium isolated from clinical source was screened using thin layer chromatography technique. The indicator strains in used were Chromobacterium violaceum CV026 and Agrobacterium tumifaciens NTI, the control strain was Pseudomonas aerugonisa PAO1. Results demonstrated that using Thin Layer Chromatography (TLC), the clinical isolate, Salmonella tympuimurium DT104 tested positive for both short chain and long chain acyl homoserine lactones.


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