Plate acoustic wave sensor for detection of small amounts of bacterial cells in micro-litre liquid samples

•Acoustic waves in piezoelectric plates are used for bacteria detection in micro-litre liquid samples.•The limit of the detection for bacterial cells in cultural Luria–Bertani broth by our method is 0.6%.•The most probable detection mechanism is the change in liquid conductivity.•Because of no using any sorbent film the long-term stability of the detection is expected as very high. Ultrasonic acoustic waves propagating in thin piezoelectric plates with free faces are used for bacteria detection in micro-litre liquid samples deposited on one of the plate surface. The limits of the detection at normal conditions are as low as 0.04% for highly diluted rich cultural Luria–Bertani broth (LB-media) in distillate water, 0.07% for bacterial cells in distillate water, and 0.6% for bacterial cells in LB-media. For all analytes the most probable detection mechanism is the change in liquid conductivity. Because of no using any sorbent film the long-term stability of the detection is expected as very high.