The effect of antimicrobial agents on the induction of tumour necrosis factor by alveolar macrophages in vitro in response to endotoxin

Alveolar macrophages from New Zealand white rabbits were incubated with twice the MIC of amikacin, ciprofloxacin, aztreonam, ceftazidime and imipenem and exposed to either 10⁴, 10⁵ or 10⁶ cfu/ml live Pseudomonas aeruginosa ATCC 27853 or 0.1, 1 or 10 mg/L purified lipopolysaccharide (LPS) derived from P. aeruginosa to determine the effects of different classes of antimicrobial agent on production of tumour necrosis factor (TNF). Incubation of macrophages with ciprofloxacin and amikacin resulted in less TNF activity after exposure to live P. aeruginosa than was found for saline, aztreonam, ceftazidime or imipenem (P < 0.05). However, no significant differences were found between any of the agents after macrophages had been exposed to purified LPS. Different antimicrobial agents therefore appear to exert different effects in vitro on the TNF response of macrophages to bacterial stimulation.