title: Disk test for the differentiation of pneumococci from other alpha-hemolytic streptococci.
abstract: One hundred twenty-five strains of Diplococcus pneumoniae and one hundred twenty-five strains of other alpha-hemolytic streptococci were planted on horse red cell-Brucella agar, and a disk of methicillin was placed on each inoculated plate. All strains were incubated anaerobically at 37 C for 24 h and then exposed to air at 6 C for 48 h. All strains of pneumococci produced a ring of beta-hemolysis surrounding the zone of inhibition produced with the methicillin disk, whereas no strain of alpha-hemolytic streptococci produced beta-hemolysis. It is suggested that this new criterion is useful for the differentiation of pneumococci from other alpha-hemolytic streptococci in those cases where other characteristics were insufficient for an unequivocal identification.
mesh_terms: D000332:Aerobiosis; D000362:Agar; D000388:Air; D000818:Animals; D001431:Bacteriological Techniques; D004912:Erythrocytes; D006460:Hemolysin Proteins / Q000032:analysis / Q000096:biosynthesis; D006736:Horses; D006801:Humans; D008712:Methicillin; D008722:Methods; D013183:Sputum / Q000382:microbiology; D013291:Streptococcus / Q000145:classification / Q000302:isolation & purification* / Q000378:metabolism; D013296:Streptococcus pneumoniae / Q000302:isolation & purification*
chemical_list: D006460:Hemolysin Proteins; D000362:Agar; D008712:Methicillin