Using a phenotype microarray and transcriptome analysis to elucidate multi-drug resistance regulated by the PhoR/PhoP...

Area of Science:

• Microbiology
• Molecular Biology
• Genetics

Background:

• The PhoRP two-component system (TCS) is crucial for Bacillus subtilis's physiological responses, especially under phosphate starvation.
• Understanding its role in antibiotic resistance is vital for combating bacterial infections.

Purpose of the Study:

• To investigate the PhoRP TCS mechanism regulating antibiotic resistance in Bacillus subtilis strain NCD-2.
• To identify specific genes and pathways involved in this resistance.

Main Methods:

• Phenotype microarray (PM) technology to assess susceptibility to 240 antimicrobial compounds.
• Transcriptional analysis to compare gene expression in wild-type, phoR-null (MR), and phoP-null (MP) mutants.
• In-frame deletion of the khtSTU operon in the MP mutant to create a double mutant (MPK).

Main Results:

• The MR mutant showed increased resistance to 13 antibiotics, while the MP mutant showed resistance to 14, including 8 ribosome-targeting ones.
• Differential gene expression analysis revealed significant changes in carbohydrate, amino acid metabolism, ABC-transporters, and phosphotransferase systems in mutants.
• The khtSTU operon, encoding a K+ efflux pump, was upregulated in the MP mutant and its deletion in the MPK mutant reduced resistance to several antibiotics.

Conclusions:

• The khtSTU operon plays a significant role in PhoP-mediated multiple antibiotic resistance in Bacillus subtilis.
• PhoRP TCS regulates antibiotic resistance through mechanisms involving the khtSTU operon and other metabolic pathways.