Effects of amoxicillin on the expression of cytokines during experimental acute otitis media caused by non-typeable Haemophilus influenzae

Antibiotics are frequently prescribed when a diagnosis of acute otitis medi a (AOM) is made in childhood, but the effects of antibiotics on host-parasi te interactions in the middle ear are not well defined. A rat model and PCR techniques were used to explore host responses during amoxicillin treatmen t of AOM caused by non-typeable Haemophilus influenzae (NTHi). The 5 day co urse of amoxicillin initiated at the otomicroscopic peak of the infection e radicated the bacteria and induced significant changes in the expression of cytokines. Interleukin (IL)-6, tumour necrosis factor-a and IL-10 were upr egulated by the treatment, and the downregulation was slower than during th e natural course. Amoxicillin inhibited the upregulation of transforming gr owth factor beta, whereas IL-1 alpha expression remained unaffected by the treatment. By comparing inflammatory host responses during treated and untr eated NTH! AOM, new targets for modification of the course, or more specifi ed and individualized treatments, may evolve.