Neisseria gonorrhoeae MlaA influences gonococcal virulence and membrane vesicle production
Fig 8
MlaA influences gonococcal fitness in vivo.
(A) In vitro competition assays were performed by combining WT FA1090 bacteria with approximately equal numbers of ΔmlaA or ΔmlaA/Plac::mlaA (~106 CFU total bacteria). Competitions were carried out in liquid medium, and output CFUs were assessed at 2, 4, and 6 h post-inoculation. Competitions with the complemented strain were performed in liquid medium both with and without IPTG. (B) Female BALB/c mice were inoculated intravaginally with approximately equal numbers of CFUs of WT and ΔmlaA bacteria (~106 CFU total N. gonorrhoeae; 7 mice per group). Vaginal swabs were taken on days 1, 3, and 5 post-infection and were cultured for CFU/mL enumeration on solid media containing streptomycin (total bacteria) or media containing streptomycin and kanamycin (ΔmlaA bacteria). Experiments were repeated three times and results are expressed as the geometric mean of the competitive index (CI): [mutant CFU (output) / WT CFU (output)] / [mutant CFU (input) / WT CFU (input)]. A CI > 1 indicates that the mutant was more fit during the competition. 1 CFU was assigned for any strain not recovered from an infected mouse. IPTG, isopropyl β-D-thiogalactopyranoside; CFU, colony forming unit.