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, res...
| Main Authors: | , |
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| Format: | Article |
| Language: | English |
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Instituto Oswaldo Cruz, Ministério da Saúde
1995-08-01
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| Series: | Memórias do Instituto Oswaldo Cruz. |
| Subjects: | |
| Online Access: | http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0074-02761995000400021 |
| Summary: | 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 (1/2MIC) 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 carbo-hydrates 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. |
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| ISSN: | 0074-0276 1678-8060 |