Kikuchi (1-1) did not allow a hit until Carlos Correa doubled to deep right-center field with one out in the seventh.
That was the only hit allowed by Kikuchi, who pitched seven innings, struck out seven and walked two, throwing 61 of 95 pitches for strikes. Kikuchi walked Alex Bregman in the first and Myles Straw in the third, then retired 11 in a row.
Kikuchi, a 30-year-old left-handed pitcher from Japan, entered Thursday with a career record of 8-16 with a 5.42 ERA since joining Seattle in 2019.
Trammell hit his fourth home run of the season in the third inning, a ball that appeared to graze the glove of a leaping Chas McCormick at the right-field wall.
Seattle stopped a four-game losing streak. Houston lost for the second time in the last eight games.
Houston starter Luis Garcia (0-3) allowed three hits and struck out six in five innings. The Astros’ bullpen held Seattle scoreless in four innings and has allowed just one run in its last 14 innings.