Randomised controlled trials (RCTs) that compared β-lactam monotherapy with the combination of an aminoglycoside and a β-lactam for treatment of hospitalised adults were eligible for inclusion in the review. Eligible studies had to report emergence of resistance of bacterial isolates, effectiveness of therapy and mortality rate. Studies of patients with neutropenia and cystic fibrosis were excluded.
Patients in included trials had a range of serious infections, which included pneumonia, sepsis, peritonitis and cholangitis. β-lactam therapy agents included ceftazidime, imipenem, cefoperazone, imipenem/cilastatin, mezlocillin, piperacillin, ceftriaxone, cefotaxime, ampicillin, cefazolin, ticarcillin and carboxypenicillin. Aminoglycosides included gentamicin, netilmicin and tobramycin.
Two reviewers independently selected studies for inclusion in the review.