NTU Undergraduates' research April 2014 - Biosciences | Seite 84

Abstract
Extended-spectrum beta-lactamases (ESBLS) are enzymes that induce resistance to a broad range of betalactam drugs including aminopenicillins, cephalosporins and monobactems. Highly prevalent in
Enterobacteriaceae, the increasing number of reported infections of this type has caused clinical issues due to
complications in the treatment of infections due to extensive resistance. The use of antibiotics as growth
promoters in livestock has caused concern that antibiotic resistant reservoirs have been produced as a result
of selective pressure and therefore ESBL resistance could be entering human systems through the food chain.
PCR and Kirby-Bauer disc diffusion assays were used to test poultry samples from retail stores in England.
15.6% of a sample of 32 Enterobacteriaceae were considered potential ESBL-producing with 3 E. coli, 1
Klebsiella spp. and 1 proteus spp. being identified. Further tests are needed to confirm the ESBL genotype
although additional studies from multiple countries have shown a high prevalence of CTX-M and SHV E. coli
isolates on poultry samples. There is correlation between CTX-M E. coli on food samples and the increasing
quantity of recorded community-acquired infections although further conclusive evidence is needed to fully
determine the source of the ESBL genes in these infections. It was concluded that drastic guidelines are
needed to reduce antibiotic use in livestock to reduce the rate in which resistance arises which could be
effecting treatment options for life threatening human infections.