Figure 1.

Inhibition of Orientia tsutsugamushi growth by antibiotics and their combinations with chloroquine. The Boryong or AFSC-4 strain of O. tsutsugamushi was inoculated into ECV304 cells and incubated in medium containing no antibiotic (N), chloroquine (C), doxycycline (D), doxycycline plus chloroquine (DC), rifampin (R), rifampin plus chloroquine (RC), azithromycin (A), or azithromycin plus chloroquine (AC) for 7 days. The number of immunofluorescence (IF)-positive foci was counted on day 8 post-inoculation. Chloroquine inhibits the growth of O. tsutsugamushi and augments the antimicrobial effect of the antibiotics against the bacterium.

^aP=0.043 by Wilcoxon signed-rank tests.