Low oxygen arrests Babesia duncani schizonts and leads to increased drug susceptibilities in hamster erythrocytes

Abstract

AbstractWe studied the effect of oxygen concentrations on the in vitro growth and drug susceptibility of Babesia duncani. We found that the growth of B. duncani required high level oxygen and the culture condition at ambient aerobic condition (21% O2) was optimal. Compared with ambient air, our results further showed that low oxygen (6-16%) could arrest B. duncani schizonts and lead to high susceptibilities to antiparasitic drugs atovaquone, pyrimethamine, quinine, and chloroquine at certain concentrations in vitro. Drug susceptibilities of other Babesia spp impacted by O2 levels need to be studied in the future, and this study indicates that culturing conditions of Babesia spp should be considered and reestablished for generating more comparable and reliable results in drug research in the future.Graphical abstractHighlightsThe in vitro growth of B. duncani requires high level oxygen and the culture condition of 5% CO2 ambient air is optimalLow level oxygen results B. duncani in low growth rate and high schizont ratio in vitroCompared with 5% CO2 ambient air, in vitro drug susceptibilities of B. duncani can be significantly increased when cultured in microaerobic condition