FIG 5.

CoPP treatment enhances antibiotic efficacy against primary pneumonic plague in the rat model. Male and female rats (cohorts of 20 to 21 animals, with 5 to 6 rats/treatment group) were challenged by aerosolized Y. pestis CO92 (individual animal doses are shown in Table S3 in the supplemental material). Oral doxycycline treatment was given daily, beginning 24 h postchallenge (Control+Dx). CoPP treatment was initiated 24 h prior to challenge (CoPP+Dx) or 24 h postchallenge (+1DPI CoPP+Dx). Control animals received PBS and water (Control). Treatments continued for 7 days. Animals were monitored for a 21-day observation period. (A) Combined data, males and females; (B) females only; (C) males only. The data shown were collected in a total of four independent trials (two trials for each sex). Data were evaluated by a Gehan-Breslow-Wilcoxon log rank test (n = 20 to 22 per group). Different letters in parentheses indicate statistical significance between groups.