Distribution of ctpA Gene in Listeriamonocytogenes

Listeria monocytogenes has potentiality to cause serious invasive disease in humans and in more than 40 animal species. L. monocytogenes is transmitted from soft cheese, milk, raw meat and sausages to human. The present study was undertaken to find the frequency of L. monocytogenes in poultry, domestic animals, sausage, cheese, milk, and also to determine ctpA(copper transport) gene among them after doing PCR on gel electrophoresis. 180 samples from brain, liver and feces of poultry(industrial hens) from 36 birderies, 166 samples of liver, brain, amniotic fluid and feces of cow, horse, sheep and goat, 80 samples of sausage, and 300 samples of dairy from shops in Karaj city were collected. L. monocytogenes was isolated by cold enrichment and standard Australia/New Zealand method. Chromosomal DNA was prepared and used for PCR amplification of ctpA. Then, PCR products ran on agarose gel electrophoresis for detection of the ctpA band. L. monocytogenes was not isolated from poultry samples. These bacteria were isolated from brain and liver of goat and sheep(12.93%), sausage(2.5%), local cheese(2.9%), and milk(2.5%). By using PCR to identify the homologus DNA in 25 L. monocytogenes isolates, 20% of them contained ctpA determinant. DNA homologus to ctpA was not detected in all isolates. Our results showed that 28.57% of cheese and 20% of domestic animal isolates, contained ctpA gene in chromosome DNA. Since ctpA gene was not existent in all isolated bacteria, this might indicate that all the strains do not have the same virulence. CtpA showed significant similarity to the proteins associated with copper metabolism disorders in humans, Menkes disease and Wilson disease. There might be a relationship between these two diseases and ctpA gene in L. monocytogenes. By producing ctpA protein of Listeria to make vaccines it is possible to prevent above diseases in future.