The resistency of Salmonella serovar. enteritidis/infantins isolated in poultry against nalidixic acid

Modern livestock production method involves the use of antimicrobial agents as an effective way to fight against various infections. The effectiveness of drugs depends on their proper and controlled use. A particular problem is bacteria, such as Salmonella, which are important for human and veterinary medicine. The mechanism of resistance developed in bacteria depends on the activity of antibacterial preparations. Target molecules for the group chinolone antibiotics are enzymes involved in DNA replication of cells. Quinolone bactericidal activity disrupts the function of bacterial gyrase thereby blocking DNA synthesis and causes cell death. Nalidixic acid is a prototype of quinolone, and along with several other compounds, forms the group of first and second generation of this type of antimicrobial agents. The subject of our work is to monitor the sensitivity of Salmonella enteritidis and Salmonella infantis to nalidixic acid as a method of indicating the presence of bacterial resistance to quinolones. The aim is to determine whether the resistance to mentioned nalidixic acid in Salmonella serovarety is present, are there differences in resistance between them and what the possible cause of these differences are. The examination was carried out on strains isolated from poultry samples. The most presented strans in both examined years were S. enteritidis and S. infantis (more than 90%). Monitoring the sensitivity of these serotypes toward nalidixic acid it was found that in 2009 S. enteritidis showed sensitivity with 88.46% and in 2010 year 81.25%. S. infantis strains showed quite a different sensitivity, i.e. the resistance to nalidixic acid. The presence of 75% resistant strains in 2009 and 68.18% resistant strains in 2010 were determined.The difference of sensitivity of isolated serovariety indicate the need to use molecular methods and try to detect not only the mechanisms of resistance but also epizootiological, epidemiological and perhaps reasons, but also the origin and circulation of strains, and determine phenotype characteristics.