News
Antibiotics resistance a major global issue
By Mawra Gohar
Antibiotics resistance is one of the major global issue which emerges from different resources including human behavior and in response such emerging issue extends throughout the world. Escherichia coli are normally present in gastrointestinal tract of human, animals and poultry birds. MDR E. coli refers to microorganism which is resistant to multiple antimicrobial agents. In poultry, antibiotics are extensively used as growth promoter especially tetracycline and chicken meat may get contaminated with MDR E. coli during processing i.e. slaughtering and evisceration, that’s why E. coli is found to be most prevalent microorganism of retail chicken meat.
In order to control bacterial problems in poultry and livestock sector, antibiotics are extensively used. Use of antibiotics in developing countries especially in Pakistan is not regularized. Antibiotics are available over the counter and are used irrationally resulting in promoting the spread of antibiotic resistance.
Plasmids are extrachromosomal DNA molecules which can replicate independently and is main vehicle for antibiotic resistance development. Plasmids carrying different genes which give specific characteristic to microorganism e.g; antibiotic resistance and enable bacteria to survive in adverse conditions. In unhygienic environment like slaughtering house, chicken carcases housed for different bacterial population which share these plasmid and result in adverse situation of antibiotics resistance with different pattern. The gastrointestinal flora of poultry birds is a common pool of resistant bacteria harboring resistance gene on plasmid and can transfer these genes from one bacterium to other.
Bacteria either generate plasmid to survive in the presence of inhibitory factors including antimicrobials. Small plasmids are easy to carry by the bacteria than large sized plasmids. As in order to carry plasmid, a bacterium has to spend large amount of energy that’s why plasmid size depends upon exposure of bacteria to inhibitory factors as well as energy status. As the spread of resistance genes is evolutionary process which requires lot of energy. In order to carry small sized plasmid, less energy is required than large sized plasmids.
It is well known that antibiotic resistance is developed due to selection pressure and it supports resistant strains and eliminates sensitive one. The greater use of antibiotics, the more chances of evolution will be emerge. MDR resistance in E. coli was may be plasmid mediated and the spread of these genes to other susceptible bacteria through different mechanisms is of great public health concern.The removal of external stimuli (i.e. overuse of antibiotics) from the environment may revert resistant bacterial strains into susceptible form.
Courtesy www.dailytimes.com.pk