General Susceptibility

Intrinsically resistant to Ampicillin. Usually susceptible to: cephalosporins including first generation, Aminoglycosides, TMP-SMX, fluoroquinolones, and Pip-Tazo. Almost always susceptible: Carbapenems, Aztreonam, Tigecycline, Colistin.

Resistant strains may be R to third generation cephalosporins (ESBLs), and rarely to carbapenems (i.e. carbapenemase enzymes).

Nitrofurantoin for UTI only, when confirmed susceptible