They are active against Haemophilus influenzae Anaerobes Most Enterobacterales (including those that produce AmpC beta-lactamase and extended-spectrum beta-lactamase [ESBL], although Proteus mirabilis tends to have a higher imipenem minimum inhibitory concentration [MIC]) Methicillin-sensitive staphylococci and streptococci, including Streptococcus pneumoniae (except possibly strains with reduced penicillin sensitivity) Most Enterococcus faecalis and many Pseudomonas aeruginosa strains, including those resistant to broad-spectrum penicillins and cephalosporins, are susceptible to imipenem, meropenem, and doripenem but are resistant to ertapenem.