FIG. 2.

Susceptibility of various strains of bacteria to a single donor’s nasal fluid. Nasal secretions from donor 4 were subjected to a modified CFU microassay of nasal fluid targeting four strains of P. aeruginosa, E. coli ML-35p, S. typhimurium wild type, and S. aureus clinical isolate. (A) Secretions tested at three different times showed similar activities against P. aeruginosa CF between 0 and 3 h but varied in the amount of regrowth at 24 h. (B) Fluid incubated with four different strains of P. aeruginosa showed strain-specific antimicrobial activity. (C) Nasal secretions permitted the slow growth of E. coli and S. typhimurium; however, S. aureus was effectively cleared. Init, inoculum (input) at time zero for each sample tested, without the addition of nasal fluid.