A special surface structure that is morphologically distinct from all the previously known conformations was found first on enteric bacteria like Escherichia coli and Salmonella enteritidis. In its architecture, a fibrillar component has been identified as bacterial amyloid. Later, amyloid structures were found on representatives of many other bacterial taxa. In this review, we give an account of the genetic information and regulation of bacterial amyloid production and its possible role in human pathology. Bacterial amyloid can mediate colonisation to environmental and host structures, initiating infections. Through interactions with host surfaces and tissue components, it can interfere with biological functions, inducing and aggravating diseases. Several data support its role in inflammation, hypocoagulation and chronic diseases like autoimmunity and neurodegeneration. Via polarisation microscopy, bacterial amyloid shows a linear positive topo-optical reaction. A strong anisoptropy can be observed after staining with various dyes, such as Congo red, eosin, thiazine red or quinolone dyes. Specific reactions for the detection of sugars, glycosaminoglycans and sialic acid revealed that these molecules are not present in bacterial amyloids. Our data show that polarisation microscopy analysis combined with confocal laser-scanning fluorescence microscopy is a promising method for gaining topo-optical insights into the fine structure of bacterial amyloids.