Efficacy and safety of aztreonam versus tobramycin for aerobic gram-negative bacilli lower respiratory tract infections

Randomized clinical trial of aztreonam and aminoglycoside antibiotics in the treatment of serious infections caused by gram-negative bacilli

“…This difference is not statistically significant (P >0.10), but because of the limited number of patients, the power of the study (1-beta) was such that a 25% or greater better response rate among the aztreonam-treated patients would have been needed to disprove the null hypothesis. Microbiologic and clinical cure rates for both groups were similar to those found by other investigators (2,3,10,11,13,15 glycosides have poor penetration and may be inactivated by respiratory secretions, and levels in sputum or even serum may barely exceed MICs for some respiratory pathogens. For this reason the optimum dosing of drugs such as tobramycin may be critical in determining the outcome of patients with nosocomial pneumonia (6).…”

“…Since the desired effect of aminoglycoside-beta-lactam synergism is to produce higher bactericidal levels and newer potent beta-lactams, such as aztreonam, produce extremely high levels in serum (as demonstrated by this study), perhaps single-drug therapy with such agents can accomplish better cure rates due to higher bactericidal concentrations. Several studies report the successful use of aztreonam alone in LRTIs (10, 11 13).…”