BMDMs pretreated for 16 h with 100 ng/ml Pam3CSK4 (Invitrogen) were infected with L. monocytogenes at an MOI of 1. At 30 min postinfection, the medium was replaced with media containing 50 µg/ml gentamicin. At 6 h postinfection, supernatants were removed and measured for lactate dehydrogenase activity as previously described (67) using a BioTek Synergy HT spectrophotometer.