Germination assay of Bacillus amyloliquefaciens as a spore-based biosensing method for detection of cell wall destruction antibiotics

Abstract

Dormant bacterial spores can sense their environments and under favorable conditions exchange their cycle from spore state to germinated one through the processes of germination and outgrowth. Here, the capability of spore germination is used to design an antibiotic bio-sensing system. Germination assays were carried out by reduction of optical density, release of Dipicolinic acid and respiration test under different germinats and various concentrations of Penicillin as a germination inhibitor. This study showed that although current germinants are not properly useful for germination of Bacillus amyloliquefaciens in starch media, presence of a small amount of cell wall destruction antibiotics (25 µg/ml) can accelerate germination but prevent outgrowth of germinated spores. So, the germinated spores cannot use the starch and stain blue with iodine reagent. This phenomenon is beneficial for detection of antibiotic residues in food and feed which are severe problem for consumers or by giving rise to the expansion of antibiotic resistances.