Carbapenems (imipenem, meropenem, doripenem and ertapenem) are bactericidal parenteral ?-lactam antibiotics which have an extremely broad spectrum of action. They are active against Haemophilus influenzae anaerobes Most Enterobacteriaceae (including those that produce ampC ?-lactamase and Extended-spectrum ?-lactamase [ESBL], although P. mirabilis tend to have higher imipenem minimum inhibition concentrations [MICs] have) methicillin-sensitive staphylococcus and streptococci, including S. pneumoniae (except possibly strains with reduced penicillin sensitivity). Most Enterococcus faecalis and many P. aeruginosa strains, including those that are resistant to broad-spectrum penicillins and cephalosporins, are prone to imipenem, meropenem and doripenem, but resistant to ertapenem. However, meropenem and doripenem are less active against E. faecalis than imipenem. Carbapenems act synergistically with aminoglycosides against P. aeruginosa. E. faecium, Stenotrophomonas maltophilia and methicillin-resistant staphylococci are resistant. Many multi-resistant nosocomial bacteria are only sensitive to carbapenems. On the other hand, the wider use of carbapenems led already to Carbapenemresistenzen. Imipenem and meropenem in meningitis penetrate into the cerebrospinal fluid. Meropenem is used for gram negative bacterial meningitis; Imipenem is not used in meningitis because it can cause seizures. Most seizures occur in patients with CNS findings or with renal failure and in those who have received inadequate high doses. Doripenem has a black Warnungsbox in which it is stated that if it is used to treat patients with ventilation-associated bacterial pneumonia, has an increased risk of death compared to imipenem. In addition, the clinical response rates were lower with doripenem. Doripenem is not approved for the treatment of pneumonia.