FIG 2.
Sialic acid treatment increases pneumococcal colonization without dissemination into the blood. Six- to eight-week-old BALB/cByJ mice were intranasally infected with 107 CFU of EF3030 Xen 11 without anesthesia. (A) After 24 h, mice were treated with either lactated Ringer's solution or 1 mg of Neu5Ac and imaged at 4 days postinfection. (B) Light emission was determined from the region of interest (ROI), the head of each mouse. Each point represents the total light detected on one animal. The horizontal red dashed line represents the lower limit of detection in each assay, which is where CFU-negative samples were plotted. The solid horizontal lines represent the medians for each data set. (C) CFU from nasal wash specimens, blood, and spleens from infected animals were enumerated. Statistical significance was determined by a Mann-Whitney rank sum test (*, P < 0.05; **, P < 0.01; ***, P < 0.001 [indicating significant differences between populations]).