Penicillin tolerance among beta-hemolytic streptococci and production of the group carbohydrates, hemolysins, hyaluronidases and deoxyribonucleases.
Penicillin tolerance among 67 strains of beta-hemolytic streptococci was examined by determining the ratio of the minimal bactericidal concentration to the minimal inhibitory concentration as 32 or greater. Tolerance was demonstrated in 15 group A strains and in 11.7, and 4 of groups B, C and G, respectively. Thereafter the effects of a subminimal inhibitory concentration (1/2 MIC) of penicillin on the bacterial products of four tolerant and four nontolerant strains (two of each Lancefield group) were analyzed and compared. The antibiotic caused a marked increase in the expression of the group carbohydrates for strains of group B. Penicillin was found to reduce the cell-bound hemolysin activities of the four tolerant strains and to increase the activity of the other (free) form of nontolerant groups A, C and G hemolysins. Penicillin caused an increase in the extracellular hyaluronidase activities of one group A and groups B, C and G streptococci. With added antibiotic the production of deoxyribonuclease by tolerant groups A, C and G was greatly enhanced and that of the group B streptococcus was arrested.
Avelino
C C
CC
Escola de Farmácia e Odontologia de Alfenas, MG, Brasil.
Benchetrit
L C
LC
D000818:Animals; D002241:Carbohydrates / Q000096:biosynthesis; D003851:Deoxyribonucleases / Q000096:biosynthesis; D006460:Hemolysin Proteins / Q000096:biosynthesis; D006801:Humans; D006821:Hyaluronoglucosaminidase / Q000096:biosynthesis; D010403:Penicillin Resistance; D013291:Streptococcus / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism
D002241:Carbohydrates; D006460:Hemolysin Proteins; D003851:Deoxyribonucleases; D006821:Hyaluronoglucosaminidase