Reassessment of extracellular and intracellular activity of macrolides, rifampicin, and doxycycline against <i>Rhodococcus equi</i> based on bacterial counts and microscopy.

ABSTRACT: Rhodococcus equi is an opportunistic intracellular pathogen responsible for severe respiratory infections in foals, requiring prolonged antibiotic treatment. Despite its in vitro susceptibility to multiple antibiotics, the in vivo eradication of intracellular R. equi remains challenging due to its ability to persist and survive within alveolar macrophages. This study aimed to assess in vitro the extracellular and intracellular activity of rifampicin, doxycycline, and four macrolides against R. equi while assessing current methodologies used to differentiate intracellular and extracellular bacteria. We found that the removal of extracellular R. equi with short times of exposure to bactericidal drugs was challenging. We thus proposed an altern

SUBMITTER: Huguet A-S 

PROVIDER: S-EPMC12403593 | biostudies-literature | 2025 Sep

REPOSITORIES: biostudies-literature