In the initial experiments we analyzed the effect of one hour pre-incubation with ketamine on the macrophage response to vancomycin-exposed CA-MRSA bacteria (MW2 and LAC). In response to vancomycinexposed MW2, pre-incubation with ketamine reduced macrophage TNF secretion by approximately 29% (p < 0.05), i.e., from 33,085 ± 867 pg/mL to 23,347 ± 862 pg/mL. Pre-incubation with ketamine led to a similar reduction (25%; p < 0.05) in macrophage TNF secretion response after stimulation with vancomycinexposed LAC (from 28,365 ± 735 pg/mL to 21,432 ± 736 pg/mL).