Revisiting the inoculum effect for Streptococcus pyogenes with a hollow fibre infection model

Severe, invasive Streptococcus pyogenes (Strep A) infections result in greater than 500,000 deaths annually. First line treatment for such infections is benzylpenicillin, often with the addition of clindamycin, but treatment failure can occur with this regimen. This failure has been partially attributed to the inoculum effect, which presents as reduced antibiotic susceptibility during high bacterial density and plateau-phase growth.

Citation:
Marum D, Manning L, Raby E. Revisiting the inoculum effect for Streptococcus pyogenes with a hollow fibre infection model. Eur J Clin Microbiol Infect Dis. 2021.

Keywords:
Benzylpenicillin; Clindamycin; Group A streptococcus; Hollow fibre infection model; Inoculum effect; Linezolid

Abstract:
Severe, invasive Streptococcus pyogenes (Strep A) infections result in greater than 500,000 deaths annually. First line treatment for such infections is benzylpenicillin, often with the addition of clindamycin, but treatment failure can occur with this regimen. This failure has been partially attributed to the inoculum effect, which presents as reduced antibiotic susceptibility during high bacterial density and plateau-phase growth.