In patients who have risk factors for antibiotic-resistant organisms, or in the absence of reliable local antibiograms, recommendations include triple therapy using 2 drugs with activity against Pseudomonas and 1 drug with activity against MRSA: An antipseudomonal cephalosporin (cefepime or ceftazidime) or an antipseudomonal carbapenem (imipenem, meropenem) or a beta-lactam / beta-lactamase inhibitor (piperacillin / tazobactam) An antipseudomonal fluoroquinolone (ciprofloxacin or levofloxacin) or an aminoglycoside (amikacin, gentamicin, tobramycin) Linezolid or vancomycin While indiscriminate use of antibiotics is a major contributor to development of antimicrobial resistance, adequacy of initial empiric antibiotics is a major determinant of a favorable outcome.