Expression of a phage RecET recombinase system improves detection of shorter DNA fragments by an Acinetobacter baylyi ADP-ISx antibiotic gene biosensor strain

Naturally competent bacteria have been engineered into sequence-specific biosensors for environmental DNA, but low recombination rates limit detection of small DNA fragments. Phage recombinases are often used to increase the efficiency of integrating DNA constructs with short homology arms into bacterial genomes. We show that expression of a RecET homolog from an Acinetobacter baumannii prophage improves Acinetobacter baylyi ADP1-ISx biosensor detection of 120- and 200-bp fragments of an antibiotic resistance gene by approximately 10- to 20-fold. This strategy can potentially enable more sensitive detection of target sequences in highly degraded DNA from environmental samples by cell-based bacterial biosensors.