蜡状芽孢杆菌表现出高度多样性的生活方式和生态位,包括有益的和致病的菌株。这些菌株在环境中普遍存在,在惰性和生活表面上发现,并持续污染食品工业的生产线。生物膜被怀疑在这种普遍存在的分布和这种持久性中起关键作用。的确,蜡状芽孢杆菌产生各种生物膜,它们的结构和形成机制不同,可能反映了对各种环境的适应。根据应变,蜡状芽孢杆菌具有生长为浸没或漂浮生物膜的能力,并在生物膜内分泌大量代谢物,表面活性剂,细菌素,酶,还有毒素,所有化合物都易于作用于生物膜本身和/或其环境。在生物膜内,蜡状芽孢杆菌以不同的生理状态存在,能够产生高度抗性和粘附性的孢子,它们本身会增加细菌对抗菌剂或清洁程序的抵抗力。目前的研究表明,尽管与广泛研究的枯草芽孢杆菌生物膜的启动和成熟所涉及的调节过程和效应分子相似,两个物种之间存在重要差异。本综述总结了关于蜡状芽孢杆菌和两种密切相关的病原体产生的生物膜的最新知识,苏云金芽孢杆菌和炭疽芽孢杆菌。本综述包括由蜡状芽孢杆菌生物膜引起的经济问题和为控制这些生物膜而实施的管理策略。其中还讨论了生物膜在这些细菌物种生命周期中的生态和功能作用,并探讨了这一重要研究领域的未来发展。
Bacillus
cereus displays a high diversity of lifestyles and ecological niches and include beneficial as well as pathogenic strains. These strains are widespread in the environment, are found on inert as well as on living surfaces and contaminate persistently the production lines of the food industry. Biofilms are suspected to play a key role in this ubiquitous distribution and in this persistency. Indeed, B.
cereus produces a variety of biofilms which differ in their architecture and mechanism of formation, possibly reflecting an adaptation to various environments. Depending on the strain, B.
cereus has the ability to grow as immersed or floating biofilms, and to secrete within the biofilm a vast array of metabolites, surfactants, bacteriocins, enzymes, and toxins, all compounds susceptible to act on the biofilm itself and/or on its environment. Within the biofilm, B.
cereus exists in different physiological states and is able to generate highly resistant and adhesive spores, which themselves will increase the resistance of the bacterium to antimicrobials or to cleaning procedures. Current researches show that, despite similarities with the regulation processes and effector molecules involved in the initiation and maturation of the extensively studied Bacillus subtilis biofilm, important differences exists between the two species. The present review summarizes the up to date knowledge on biofilms produced by B.
cereus and by two closely related pathogens, Bacillus thuringiensis and Bacillus anthracis. Economic issues caused by B. cereus biofilms and management strategies implemented to control these biofilms are included in this review, which also discuss the ecological and functional roles of biofilms in the lifecycle of these bacterial species and explore future developments in this important research area.