Criteria for DTR: resistance (intermediate to full) to all first-line antibiotics by in vitro susceptibility testing:
(1) all reported carbapenems (requires at least 1)
(2) all reported beta-lactams (requires >= 1 extended spectrum cephalosporins)
(3) all reported fluoroquinolones (requires at least 1)
(4) piperacillin-tazobactam (if reported)
(5) ampicillin-sulbactam (if reported)
(6) aztreonam (if reported)
where:
• Antibiotic susceptibility studies may only report results for one antibiotic in a class.
An organism classified as DTR:
(1) would be classified as multi-drug resistant
(2) overlaps with extensive drug resistance
(3) does not need to show resistance to all antibiotics (pan-drug resistance).
An organism that is DTR requires therapy with less effective or more toxic secondary agents. This means that
(1) therapy may be less effective or more toxic
(2) the risk of mortality is greater
