Antibiotic use at 6 community nursing homes in 2013. A. Total number of antibiotic prescriptions, stratified by length of therapy. B. Rates of antibiotic use, grouped by pharmacological class. Antibiotics grouped as Other include the following classes (or agents): aminoglycosides, monobactam (aztreonam), carbapenems, lipopeptide (daptomycin), macrocyclic (fidaxomycin), fosfomycin, and rifamycins. B-lactam is beta-lactam; gen is generation; iv is intravenous.