REDUCING MEDIUM FOR THE CULTIVATION OF PORPHYROMONAS-GINGIVALIS

Porphyromonas gingivalis, a micro-organism frequently associated with human periodontal diseases, is commonly cultured under a reducing atmo sphere in enclosed cabinets or glove boxes. This paper reports a modif ied Wilkins-Chalgren (MWC) medium for the culture of Fl gingivalis und er atmospheric conditions at 37 degrees C. On the basis of preliminary tests, WC broth was supplemented as follows: 500 mg/l cysteine hydroc hloride; 250 mg/l sodium thioglycolate; and 1,000 mg/l sodium bicarbon ate. Three Fl gingivalis isolates (JKG-I, 33277 and A7436) showed very similar growth over 24 and 48 h periods when cultured both in WC medi um in an anaerobic chamber and in the MWC medium. Culture of these iso lates both in the anaerobic chamber and in the MWC medium yielded very similar data with respect to trypsin-like activity, total protease ac tivity, and reactivity to monoclonal antibodies specific for P. gingiv alis. Growth in the MWC medium varied over a 3- to 4-fold range for se ven additional isolates (JKG-7, D86B6, D13B11, D84D2, JKG9, D67D9, D82 F5) over 24 and 48 h periods.