The effect of subminimal inhibitory concentrations of penicillin on growth rate and haemolysin activity of group G Streptococcus

The influence of the subminimal inhibitory concentrations (1/3 and 1/4 of the MIC) of penicillin on growth rate and on haemolysin production of a strain of group G Streptococcus was studied. It was shown that 1/3 of the MIC almost completely inhibited the bacterial growth, but it was not able to inh...

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Bibliographic Details
Main Authors: Verônica V. Vieira, Louis Barrucand, Angela C. D. Castro
Format: Article
Language:English
Published: Fundação Oswaldo Cruz (FIOCRUZ) 1993-09-01
Series:Memorias do Instituto Oswaldo Cruz
Subjects:
Online Access:http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0074-02761993000300013
Description
Summary:The influence of the subminimal inhibitory concentrations (1/3 and 1/4 of the MIC) of penicillin on growth rate and on haemolysin production of a strain of group G Streptococcus was studied. It was shown that 1/3 of the MIC almost completely inhibited the bacterial growth, but it was not able to inhibit haemolysin activity in the culture supernate. The generation time of bacteria grown in 1/4 of the MIC was approximately twice longer than that of the control culture. In all cultures, the haemolysin, after being produced (or liberated), reached a peak and decreased to low levels, which could suggest that group G Streptococcus produces some end products of metabolism that are able to inhibit haemolysin activity.
ISSN:0074-0276
1678-8060