Gram positive:

• No Gram positive aerobes

Gram negative:

• No Gram negative aerobes

Anaerobic:

• Most including Bacteroides fragilis

• Clostridia (including C. difficile, excluding Propionibacterium acnes)

Other:

• H. pylori

• Anaerobic protazoa (Entamoeba, Giardia, Trichomonas)