Bacillus “next generation” diagnostics: moving from detection toward subtyping and risk-related strain profiling

Abstract

The highly heterogeneous genus Bacillus comprises the largest species group of endospore forming bacteria. Because of their ubiquitous nature, Bacillus spores can enter food production at several stages resulting in significant economic losses and posing a potential risk to consumers due the capacity of certain Bacillus strains for toxin production. In the past, food microbiological diagnostics was focused on the determination of species using conventional culture-based methods, which are still widely used. However, due to the extreme intra-species diversity found in the genus Bacillus, DNA-based identification and typing methods are gaining increasing importance in routine diagnostics. Several studies showed that certain characteristics are rather strain-dependent than species-specific. Therefore, the challenge for current and future Bacillus diagnostics is not only the efficient and accurate identification on species level but also the development of rapid methods to identify strains with specific characteristics (such as stress resistance or spoilage potential), trace contamination sources, and last but not least discriminate potential hazardous strains from non-toxic strains.

Bacillus cereus—a Multifaceted Opportunistic Pathogen

“…However, in the light of consumer protection, it is expected that in the future, the focus will move toward risk-orientated differential diagnostics by including methods for detection of toxins, toxin genes, and virulence markers. Indeed, in the context of foodborne outbreak investigations, molecular typing and toxin gene profiling are already of much higher importance than the differentiation between the species of the B. cereus group (for review, see [15]). The cytotoxin K exists in two variants, cytotoxin K 1 (CytK-1) and cytotoxin K 2 (CytK-2).…”

Isolation of Bacillus cereus Group from the Fecal Material of Endangered Wood Turtles

“…In other studies, this gene has also been found to be the most frequent toxin gene present [6,9,20,26,27,33]. Nhe genes are believed to be the most common enterotoxin genes [23].…”

Label-free, non-invasive light scattering sensor for rapid screening of Bacillus colonies

“…As a bio-threat agent, the significance of B. anthracis to public health is enormous (Irenge and Gala, 2012). The similarities between the Bacillus species at the morphological, biochemical, and genomic level render inter-species differentiation difficult (Ehling-Schulz and Messelhaeusser, 2013;Klee et al, 2006;Soufiane and Côté, 2009). However, these similarities as one group reinforce the requirement for their differentiation from other non-Bacillus bacteria.…”