Do you consider use of oral antibiotics for complicated polymicrobial intra-abdominal infections?    

Depends on how you're defining "complicated" IAI. Source control is key (I like this review: Source Control and Antibiotics in Intra-Abdominal Infections), especially if there's a fistula or anastomotic leak; but once an abscess is <5cm, if I have oral options that the patient can tolerate/dosed ...