The 37-year-old joined from Valencia in 2012 and made his debut in a 3-0 League Cup defeat at Swindon.
The right-back was made club captain last summer and helped the Seagulls clinch promotion into the Premier League for the first time in their history.
Brighton sit 12th in the top flight with 12 points from ten games and Bruno admitted his pride at reaching a landmark appearance for the club.
He said: "It's a special day and it was a good result.
"It was a bad start (at Swindon) but I'm happy and really proud to have played 200 games for this club."
On the draw against the Saints, Bruno said: "We know Southampton are a really good side, even though the table is maybe not saying that. They've got a massive squad with really good players.
"To be honest, they were lucky with the goal and after that we reacted really well and in the first half were much better than them. We had a few chances and they didn't have anything else.
"To play like that against a team like Southampton says a lot about ourselves."