THE "IN VIVO SENSITIVITY TEST"—BACTERIOLOGY OF MIDDLE EAR EXUDATE : During Antimicrobial Therapy in Otitis Media

During a 27-month study into the bacterial etiology of otitis media by needle aspiration and culture of the middle ear exudate, the efficacy of various antibiotics was evaluated. There were 858 episodes of otitis media studied with 1,233 aspirates and cultures performed, 271 of these during antimicrobial therapy-the "In Vivo Sensitivity Test." The antibiotics were prescribed to each patient on an individual basis with a general plan to alternate between two drugs during a given time period. When feasible, middle ear fluid was aspirated and cultured regardless of the patient's clinical response. Pneumococcus or H. influenzae was most effectively eliminated from middle ear exudate with ampicillin, phenoxymethyl penicillin with sulfonamides, and erythromycinsulfa. Long-acting sulfonamides, triple sulfonamide, and tetracycline are frequently ineffective against pneumococcus in middle ear exudate while benzathine penicillin, phenoxymethyl penicillin, and erythromycin are frequently ineffective against H. influenzae in middle ear exudate.