Tuberculosis of bones and joints: diagnostic approaches

Mycobacterial and routine aerobic and anaerobic cultures were made prospectively from 22 patients with bone and/or joint tuberculosis. Mycobacteria were found on direct smear in 6 patients (27.3%), on culture in 14 (63.6%) and on histological section in 5 (22.7%). In one patient routine culture at operation revealed growth of Nocardia asteroides and Moraxella catarrhalis in addition to a positive culture of mycobacteria. Routine sinus culture showed growth of Staphylococcus epidermis in 3 out of 8 patients with draining sinuses. Thus, isolation of avirulent pyogenic bacteria from an operative or sinus specimen does not exclude the possibility of tuberculosis. Mycobacteria can often be identified from sinus-track culture in patients in whom operative culture, histopathological and clinical examination have failed to confirm the diagnosis of tuberculosis. Tuberculosis should be suspected if there are pus cells without pyogenic bacteria on direct smear, if there is no growth of any pyogenic bacteria or if there is growth of Staphylococcus epidermidis alone on routine aerobic and anaerobic sinus cultures.