Which antigens are associated with the OX19 and OX2 strains?

The correct association is with Rickettsia species. OX19 and OX2 are specific antigens that are part of the Rickettsia genus, particularly used in serological testing to identify different strains within this group of bacteria. OX19 is commonly associated with Rickettsia rickettsii, the causative agent of Rocky Mountain spotted fever, while OX2 is linked to other Rickettsial infections. Understanding these antigens is crucial for diagnosing infections caused by Rickettsia, as serological tests leverage these specific markers to detect antibodies in patient samples.

The other options involve different types of bacteria or antigens that do not correlate with the OX19 or OX2 antigens. Escherichia coli and Proteus vulgaris are both enteric bacteria and do not produce these specific antigens. Mycobacterium tuberculosis, the causative agent of tuberculosis, has its own set of antigens that differ significantly from those associated with Rickettsia. Therefore, the focus on OX19 and OX2 as indicators specific to Rickettsia species is key in understanding their role in immunological testing.