The importance of characterizing antibiotic resistance genes in environmental microorganisms is becoming apparent as recent research highlights the ability of environmental microorganisms to act as antibiotic resistance gene reservoirs for clinical pathogens. The genome of the soil bacterium, Brachybacterium faecium, was sequenced in 2009, after which the genome underwent automated annotation. An examination of the automatically annotated genome suggested the presence of eleven putative β-lactamase genes. β-lactamase is an enzyme that provides resistance to β-lactam antibiotics. Six of the eleven putative β-lactamase genes were identified via manual annotation—using Integrated Microbial Genomes Annotation Collaborative Toolkit software—as candidates for laboratory analysis for β-lactamase activity. The ability of the putative β-lactamase gene products to provide β-lactam resistance to Escherichia coli—a model bacterium that lacks intrinsic β-lactam resistance—was determined via PCR amplification of the putative β-lactamase genes in B. faecium, transformation of competent E. coli cells with expression vectors containing the six putative β-lactamase genes and subsequent culture dependent determination of the minimum inhibitory concentration of β-lactam antibiotics. Characterization of viable β-lactamase genes within B. faecium may provide evidence for the potential of environmental microorganisms to act as antibiotic resistance gene reservoirs and may enable researchers to minimize clinical antibiotic resistance via proper utilization of current clinical antibiotics and strategic synthesis of new antibiotics with low environmental resistance gene frequencies.
