Epidemiological markers are methods used to detect the various types/group and subtypes/subgroup of microorganisms responsible for an epidemic outbreak, so that the source of spreading could be located and effective remedial measures taken to contain the outbreak. A single bacterial species with a particular set of pathogenic activities may nevertheless include strains of different types that are distinguishable in minor characters. Recognition of the type a strain isolated from a patient my be of epidemiological value in tracing sources or modes of spread of infection in a community.