It does sound like a bacteria/fungus. Are your plants very close together? They need air circulating between them to prevent fugal buildup. Pruning also helps - cutting off the bottom leaves and suckers. See the two fact sheet below for tips on pruning tomatoes. 

Other things you can do are removing affected leaves and spraying weekly with neem oil or cooper sulfide which are anti fungal organic sprays. Make sure to read and follow the directions on the package.

By the way, can we add you to our email list to send you notices about our upcoming events and educational opportunities?

Good luck,

Karen

Master Gardener Volunteer