Antibiotic susceptibility profiles of penicillins, macrolides, tetracyclines, clindamycin, metronidazole, rifampin, TMP-SMX, and chloramphenicol; antibiotic susceptibility profiles of cephalosporins; and antibiotic susceptibility profiles of (aminoglycosides, fluoroquinolones, colistin, polymyxin B, aztreonam, tigecycline, vancomycin, quinupristin/dalf opristin, linezolid, tedizolid, daptomycin, telavancin, dalba vancin, oritavancin, nitrofurantoin, fosfomycin, and carbapenems are tabulated in this chapter which are self-explanatory. Gram stain of isolates; key factors in antibiotic selection; clinically relevant types of antibiotic resistance; clinical significance of an isolate by body site and selection of initial empiric antibiotic therapy pending susceptibility testing, aerobic isolates, capnophilic isolates, anaerobic isolates, and yeast/fungi; antibiotic mechanisms of action and resistance, empiric antibiotic therapy of selected problem pathogens; and clinical interpretation of gram stain are also covered in this chapter.