<prompt> Most common organism associated with reactive ahritis isStaphylococcusShigellaChlamydiaYersinia  <response>: Reactive spondyloahritis ReA is a reaction to a number of bacterial triggers with clinical features in keeping with all SpA conditions. The known triggers are Chlamydia, Campylobacter, Salmonella, Shigella and Yersinia. Notably, non-SpA-related reactive ahritis can occur following infection with many viruses, Mycoplasma, Borrelia, streptococci and mycobacteria, including M. leprae, which causes leprosy Hansens disease; however, the reaction in these instances consists typically of myoahralgias, is not associated with HLA-B27 and is generally not chronic. The ahritis associated with rheumatic fever is also an example of a reactive ahritis that is not associated with HLA-B27.Sexually acquired reactive ahritis SARA is predominantly a disease of young men, with a malepreponderance of 15 : 1. This may reflect a difficulty in diagnosing the condition in young women, in whom Chlamydia infection is often asymptomatic and is hard to detect in practical terms. Between 1 and 2 of patients with non-specific urethritis seen at genitourinary medicine clinics have SARA. The syndrome of chlamydial urethritis, conjunctivitis and reactive ahritis was formerly known as Reiters disease. Ref Davidsons 23e p1031 