In vitro evaluation of antibiotic resistance and PGP traits in NR5
NR5 was evaluated for its resistance/susceptibility towards 20 antibiotics viz . Amikacin (AK) 30µg, Ampicillin (AMP) 10µg, Amoxycillin (AMX) 10µg, Cefadroxil (CFR) 30µg, Cefoperazone (CPZ) 75µg, Ceftazidime (CAZ) 30µg, Ceftriaxone (CTR) 30µg, Chloramphenicol (C) 30µg, Ciprofloxacin (CIP) 5µg, Cloxacillin (COX) 1µg, Co-Trimoxazole (COT) 25µg, Erythromycin (E) 15µg, Gentamicin (GEN) 10µg, Nalidixic Acid (NA) 10µg, Netillin (NET) 10µg, Nitrofurantoin (NIT) 300µg, Norfloxacin (NX) 10µg, Penicillin (P) 10Unit, Tobramycin (TOB) 10µg, and Vancomycin (VA) 30µg. Bacterial culture of NR5 was plated onto nutrient agar plate and antibiotic discs (Icosa 006, HiMedi a Pvt. Ltd.) were placed over it. Plate was incubated at 30°C for 24 h to observe the bacterial tolerance against different antibiotics by measuring zone diameter.
Bacillus mycoides NR5 was screened in vitro for various plant growth promoting (PGP) traits like - Siderophore production by CAS agar method and Universal Chemical Assay [CAS] by Schwyn and Neilands (1987); Nitrate reduction Cappuccino & Sherman (1992); ammonia production by Ahmad et al. (2008); phosphate solubilization (Gaur,1990) and IAA production by Gutierrez et al. (2009) and Hydrocyanic acid (HCN) production as per method given by Miller et al. (1970).