Infection of Knee Joint by Mycobacterium kansasii

Excerpt

EXTRAPULMONARY infections caused by unclassified acid-fast mycobacteria of Runyon group I photochromogenic type without accompanying pulmonary disease have been rarely reported. It is generally accepted that two of the Runyon groups' of atypical mycobacteria are capable of producing progressive disease. One is group I, photochromogenic Mycobacterium kansasii. This group is characterized by colonial pigmentation following purposeful exposure of the culture to light. These microorganisms often possess a natural resistance to the major antituberculous drugs in low concentration. Experience with in vitro drugsensitivity testing has taught the need for initially higher doses of drugs, particularly isoniazid (INH). It is with this well-defined group of mycobacteria that the present case is identified.

Group III, nonchromogenic Battey strain of atypical mycobacteria, produces indolent disease that is difficult, if at all possible, to reproduce in laboratory animals. It possesses natural resistance to low concentrations of antituberculous drugs. It is easily differentiated from M tuberculosis