PCR-Restriction Fragment Length Polymorphism analysis of fljB gene in Salmonella enterica subspecies enterica serovar Typhimurium isolated from avians

Economic constraint of diseases arising from Salmonella Typhimurium causes the study of this zoonotic organism more important. Most studies on identification and characterization of S. Typhimurium are conducted at DNA level. Flagellin genes (fliC and fljB genes encoding phase-1 and phase-2 flagella, respectively) are useful as a model system for studying genetic differentiation. The objectives of the present study were to identify the polymorphism of fljB among avians in different regions by the PCR-RFLP method. Fifty-two S. Typhimurium isolates out of 1,870 intestine samples were identified using culture and serotyping as well as multiplex-PCR (broiler (n = 13), layer (n = 12), duck (n = 5), goose (n = 5), sparrow (n = 8), canary (n = 3), pigeon (n = 5) and casco parrot (n = 1)). Amplification of fljB gene was performed and amplified products subjected to restriction digestion with Hha I enzyme. Two RFLP patterns generated DNA fragments between approximately 50 to 800 bps. Pattern A was observed in 33 (63.46%) and pattern B in 19 (36.54%) of isolates. Salmonella Typhimurium recovered from 13 broilers (ten with pattern A and 3 with pattern B) and 8 sparrow (three with pattern A and 5 with pattern B) showed both A and B patterns. Twelve layers, 5 pigeons and 3 canaries showed pattern A and 5 ducks, 5 geese and one casco parrot showed pattern B. None of these patterns was allotted for a special region. The results of the present study showed that fljB gene is highly conserved among avians in different geographical regions, suggesting not only the importance of fljB gene in survival of organism in different environmental conditions but also the relation between proteins encoded by fljB gene and serotyping scheme.