Corynebacterium is a genus of bacteria that are typically rod-shaped and can be found in various environments, including soil and water. Some species are part of the normal flora of human skin and mucous membranes, while others can cause diseases. One well-known pathogenic species is Corynebacterium diphtheriae, which is responsible for diphtheria, a serious respiratory illness. These bacteria are characterized by their unique cell wall structure, which contains a high proportion of mycolic acids. This feature makes them resistant to certain antibiotics and contributes to their survival in harsh conditions. Corynebacterium species can be identified through specific laboratory tests, including culture and biochemical assays.