Isolation ofCapnocytophaga Species witha New Selective Medium

A selective medium(CAP)composed ofa GC agarbasesupplemented with1% hemoglobin, 1% Polyvitex, andan antibiotic mixture ofpolymyxin B (15U/ml), vancomycin (5,ug/ml), trimethoprim (2.5,ug/ml), and amphotericin B (2.5,ig/ml) was compared withanother selective medium(TBBP)andtwononselective media-ablood agaranda chocolate agar-toisolate Capnocytophaga species from725clinical specimens. Theseincluded sputa(467specimens), throat swabs(116specimens), oralulcerations (35specimens), and periodontal pockets (107specimens). TherecoveryrateofCapnocytophaga species wassignificantly higher with theCAPmedium(96%)thanwiththeselective TBBPmedium(52.2%), thenonselective blood agar(6.2%), andthechocolate agar(4.6%). Growthofthenormalflora was bestinhibited onCAPmedium.Colony size and yellow-brown pigment formation were maximally expressed on chocolate agarandCAPmedium,butgliding motility was mostly absent. We conclude thattheCAP mediumisan excellent mediumfortherecoveryof Capnocytophaga species fromcontaminated clinical specimens. Thegenus Capnocytophaga hasbeenidentified aspartof thenormalgingival flora inhumansandappearstobe important intheetiology oflocalized juvenile periodontitis (17). Several reports indicate thatCapnocytophaga species can causesepsis inimmunocompromised