Bacteria Susceptible to Ertapenem
Ertapenem is effective against a broad spectrum of gram-positive, gram-negative aerobic and anaerobic bacteria, including Enterobacteriaceae, but lacks activity against Pseudomonas aeruginosa, Acinetobacter species, methicillin-resistant staphylococci, and enterococci. 1
Gram-positive Bacteria Susceptible to Ertapenem
- Staphylococcus aureus (methicillin susceptible isolates only) 2
- Staphylococcus epidermidis (methicillin susceptible isolates only) 2
- Streptococcus agalactiae 2
- Streptococcus pneumoniae (penicillin susceptible and penicillin-intermediate isolates) 2
- Streptococcus pyogenes 2
Gram-negative Bacteria Susceptible to Ertapenem
- Escherichia coli, including ESBL-producing strains 2, 1
- Haemophilus influenzae (beta-lactamase negative and positive isolates) 2
- Klebsiella pneumoniae, including many ESBL-producing strains 2, 1
- Klebsiella oxytoca (excluding ESBL producing isolates) 2, 3
- Moraxella catarrhalis 2
- Proteus mirabilis 2
- Citrobacter freundii 2
- Citrobacter koseri 2
- Enterobacter aerogenes 2
- Enterobacter cloacae 2, 4
- Haemophilus parainfluenzae 2
- Morganella morganii 2
- Proteus vulgaris 2
- Providencia rettgeri 2
- Providencia stuartii 2
- Serratia marcescens 2
Anaerobic Bacteria Susceptible to Ertapenem
- Bacteroides fragilis 2
- Bacteroides distasonis 2
- Bacteroides ovatus 2
- Bacteroides thetaiotaomicron 2
- Bacteroides uniformis 2
- Bacteroides vulgatus 2
- Clostridium clostridioforme 2
- Clostridium perfringens 2
- Eubacterium lentum 2
- Fusobacterium species 2
- Peptostreptococcus species 2
- Porphyromonas asaccharolytica 2
- Prevotella bivia 2
Important Clinical Considerations
- Ertapenem is particularly useful against ESBL-producing Enterobacteriaceae, making it valuable for treating infections caused by these multidrug-resistant organisms 1, 5
- Ertapenem has restricted activity against nosocomial pathogens such as Pseudomonas aeruginosa, Acinetobacter species, methicillin-resistant staphylococci, and enterococci 1, 5
- Ertapenem is stable against hydrolysis by a variety of beta-lactamases, including penicillinases, cephalosporinases, and extended-spectrum beta-lactamases, but is hydrolyzed by metallo-beta-lactamases 2
- In Taiwan, ertapenem is widely used for treating infections due to ESBL-producing and multidrug-resistant Enterobacteriaceae 4
Resistance Patterns to Note
- Resistance to ertapenem is most commonly attributable to mechanisms including alterations in penicillin-binding proteins in gram-positive organisms, and combinations of metallo-beta-lactamase enzymes, porin protein defects, and efflux pumps in gram-negative organisms 1
- When using newer MIC interpretive breakpoints for carbapenems, an additional 12% of ESBL-producing K. pneumoniae isolates and 27% of Enterobacter cloacae isolates were found to be non-susceptible to ertapenem compared with older criteria 4
- The Clinical and Laboratory Standards Institute (CLSI) recommends that when using the new interpretive criteria for carbapenems, modified Hodge testing for Klebsiella pneumoniae carbapenemases (KPC) is not needed except for epidemiology and infection control purposes 4
Ertapenem's once-daily dosing and broad-spectrum activity make it particularly useful for treating complicated intra-abdominal infections, complicated skin and skin structure infections, community-acquired pneumonia, complicated urinary tract infections, and acute pelvic infections 2, 5.