Extreme-drug resistance indicates resistance to all of the following:
(1) ceftazidime, cefepime and other antipseudomonal cephalosporins
(2) beta-lactam and beta-lactamase inhibitor combinations (ampicillin + sulbactam, ticarcillin + clavulanate, piperacillin + tazobactam)
(3) imipenem, meropenem and other antipseudomonal carbapenems
(4) levofloxacin, ciprofloxacin and other fluoroquinolones with antipseudomonal activity
(5) gentamicin, tobramycin, amikacin and other aminoglycosides
(6) tigecycline
(7) polymyxin B, colistin and other polymyxins
where:
• Susceptibility testing is not done against all of these antibiotics; it is limited for an agent that is representative for the group.
• Testing must be performed in accordance with standard guidelines.
• Resistance to all 4 items 1, 2, 3 and 4 indicates panresistance.
