The genus Barnesiella showed protective effect both in IS (β = −0.11, OR [95% CI] = 0.90 [0.81, 1.00], p = 0.04) and small vessel stroke (SVS; β = −0.33, OR [95% CI] = 0.72 [0.58, 0.90], p = 4.59 × 10−3) but posed a risk effect on neuromyelitis optica spectrum disorder (NMOSD; β = 1.08, OR [95% CI] = 2.95 [1.09, 7.98], p = 0.03) and aquaporin-4 immunoglobulin G-positive neuromyelitis optica spectrum disorder (AQP4-IgG+ NMOSD; β = 1.54, OR [95% CI] = 4.64 [1.34, 16.11], p = 0.02). Here, AQP4 is linked to neuromyelitis optica.