Document Type : Original Article
Microbiology Department, Iran Medical Sciences University, Tehran, Iran
Introduction: Listeria monocytogenes is a Gram positive bacterium, often found in the environment and is responsible for serious food-borne diseases such as perinatal infections, septicaemia and meningoencephalitis in humans and animals. For this reason, distribution of the ctp A (copper transport protein A) among L. monocytogenes was isolated from clinical, environment, dairy, and poultry samples, and was investigated. Then, ctp A gene was transferred into E.coli DH5-?.
Materials and Methods: This investigation was carried out in two steps (ctpA was found in L. monocytogenes isolated from different sources, which was kept in culture collection of Adelaide University, Australia. Then ctpA gene was transferred into E. coliDH5-?. CtpA DNA from L. monocytogenes was amplified by PCR, identified on agarose gel, purified by phenol, and ligated intopGEM-T vector. Then, it was transferred on X-gal plate containing ampicillin. The sequencing of ctpA DNA was determined by using dyeterminator kit to purify DNA, and followed by sequencing machine. Results: By using PCR to identify the homologous DNA in 69 isolates, 38% of tested isolates contained ctpA determinant. Our results showed that: 90% of clinical and dairy isolates; 85% of environmental isolates and 7% of poultry isolates of L. monocytogenes contained ctpA in chromosome DNA. Fortunately, the transformation of ctpA from L. monocytogenes into E. coli DH5-a was successful.
Conclusion: Since, the existence of ctpA in clinical, dairy and environmental samples was 90% and in poultry was 7%, there fore, the virulence of all strains of this bacteria are not the same. Introducing such clone (ctpA gene) into suitable carrier strains, could be expected to produce a good oral immunogen against L. monocytogenes.