“…Thirty-six evaluable studies were published during 1980-1989 , and 29 studies were published from 1990 through October 2004 . Thirteen studies were excluded from further analysis for various reasons: 7 studies were excluded because they examined perioperative anti-infective prophylaxis [16,19,27,55,58,63,68], 3 were excluded because they were performed with immunocompromised patients [22,69,73], 1 was excluded because patients were stratified and received combination therapy or monotherapy according to the severity of disease [75], 1 was excluded because it was a comparative but not randomized trial [46], and 1 was excluded because the studied aminoglycoside was administered endotracheally [43].…”