Comparison of Beta-lactamase Genes in Environmental Rahnella Isolates

Antibiotic resistance is a growing problem in the field of healthcare. Antibiotics are becoming less effective as species of bacteria adapt and share resistance mechanisms. If transmission of mechanisms can be better understood at the molecular level, inhibitors could be developed to lessen the likelihood of antibiotic resistance. In this study, Rahnella spp were isolated from environmental sources on MacConkey plates containing 100 µg ml-1 ampicillin, and confirmed by 16S rRNA gene sequencing. Whole genomic DNA was extracted from isolates and initial amplifications were performed by polymerase chain reaction (PCR) using primers specific for 16S amplification. New primers were designed based on the sequence of a β-lactamase gene identified in a Rahnella genome. These primers provided strong amplification. The products of these amplifications were sequenced, with the predicted protein products showing high sequence similarities to a previously identified Rahnella β-lactamase gene. Individual sequences were compared and found to cluster into two distinct groups, with each being distinct from the known Rahnella β-lactamase. Additional sequence data was used to determine the full sequences of this class A beta-lactamase gene predicted to be responsible for beta-lactam resistance. Primers were produced to amplify the full gene and a High Fidelity PCR Kit by Qiagen was used to amplify the gene and furthermore, sequence the full gene. Ongoing research is being conducted to understand more about the mechanism by which the class A beta-lactamase gene confers resistance and additionally how this resistance is transferred between bacteria