Oct 27 (Reuters) - U.S. stock indexes opened slightly higher on Wednesday, helped by a fresh batch of upbeat earnings reports. The Dow Jones Industrial Average rose 78.55 points, or 0.22%, at the open to 35,835.43. The S&P 500 opened higher by 5.43 points, or 0.12%, at 4,580.22, while the Nasdaq Composite gained 40.29 points, or 0.26%, to 15,276.00 at the opening bell. (Reporting by Devik Jain in Bengaluru)