Bacteria in the chronic ear. Pre- and postoperative evaluation

Results of bacteriological analyses carried out in 480 chronic ears showed that initially, 401 ears (83.5%) were infected; the most frequent bacteria were <i>Ps</i>. <i>aeruginosa</i> and <i>St</i>. <i>aureus</i> (22.5 and 21.3%). Local preoperative treatment reduced the number of infected ears to 48.2%. Specimens from the mastoid antrum and/or cells were positive in 50% of cholesteatoma ears and 20% of chronic ostitic ears. Bacteria were cultured even in 11% in dry or culture-negative ears. <i>Ps</i>. <i>aeruginosa</i> strains were most sensitive to streptomycin (69%) and next to colistin (31%). <i>St</i>. <i>aureus</i> was best sensitive to streptomycin (90%) and chloramphenicol (72%). Against Proteus strains, streptomycin was the most effective (82%) followed next by chloramphenicol (70%). Postoperative wound infection appeared in 11 ears (2.3%) and was most often due to <i>St</i>. <i>aureus</i>. Prolonged middle ear and ear canal infection continued postoperatively in 37 ears (7.7%), the main agent being <i>Ps</i>. <i>aeruginosa</i>.