Fig. 2

Detection of S. pneumoniae with Spn-FLUO in human specimens. (A) Detection algorithm for the identification of Spn in clinical specimens. Five fields were screened using the 60x objective, and a specimen was scored positive when ≥ 1 to < 5 (+), ≥ 5 to < 10 (++), or ≥ 10 (+++) pneumococci were observed in at least three fields. This algorithm was chosen to ensure the reliable detection of Spn while minimizing the risk of false positives. (B) The density of S. pneumoniae in nasopharyngeal specimens that yielded a positive reaction with Spn-FLUO was categorized depending on the semiquantitative algorithm. Data are presented as mean ± SD. Differences in bacterial density were determined using one-way ANOVA followed by Dunnett’s multiple comparisons test. ns = no significant difference. (C-D) Sputum specimen stained with Spn-FLUO and observed under (C) bright field and (D) epifluorescence in the green channel. Arrows point out Spn identified by Spn-FLUO