Rapid, Sensitive, and Selective Quantification of Bacillus cereus Spores Using xMAP Technology

Area of Science:

• Microbiology
• Biotechnology
• Analytical Chemistry

Background:

• Bacillus cereus is a common cause of foodborne illness, and current detection methods are slow and imprecise.
• Accurate and rapid detection of B. cereus spores is crucial for food safety and public health.

Purpose of the Study:

• To develop a sensitive and selective quantitative detection system for Bacillus cereus spores.
• To evaluate the efficacy of aptamers and antibodies targeting the Bacillus (BclA) protein for spore detection.
• To demonstrate the potential for multiplexed pathogen detection using the developed system.

Main Methods:

• Screening of commercial antibodies and DNA aptamer sequences for affinity to Bacillus collagen-like protein A (BclA).
• Testing sensitivity and selectivity of selected reagents using immunoassays and xMAP (multi-analyte profiling).
• Validation in complex matrices, including mixtures of microorganisms and food samples, and simultaneous detection of multiple pathogens.

Main Results:

• A llama-derived recombinant antibody showed B. cereus spore selectivity and sensitivity between 10^2 and 10^5 spores/mL via xMAP.
• DNA aptamers demonstrated sensitivity from 10^3 to 10^7 spores/mL with no cross-reactivity to B. megaterium or B. subtilis.
• Selective detection of B. cereus spores was achieved in mixed microbial samples and food, and simultaneous detection of B. cereus, E. coli, P. aeruginosa, and S. cerevisiae was demonstrated.

Conclusions:

• The study successfully developed a rapid, sensitive, and selective system for quantifying B. cereus spores.
• The findings support the potential for multiplexed monitoring of human pathogens in complex environments.
• This approach offers a significant advancement over traditional, laborious detection methods.