CefotetanCephalosporinsCephamycinsCefmetazoleCefoxitinCefoperazoneMicrobial Sensitivity TestsAnti-Bacterial Agentsbeta-Lactamasesbeta-LactamsCephalosporin ResistanceBacteroides fragilisColorectal SurgeryCefazolinCephaloridineBacteria, AnaerobicCephalosporinaseEnterobacteriaceaeCefotaximeCephalexinDrug Resistance, MicrobialBacteriaMoxalactamCefixime