Enterobacteriaceae are a family of germs that most commonly live in a person's bowel without causing any disease. Carbapenems are strong antibiotics that are commonly used to treat serious infections. A few enterobacteriaceaea have gained resistance to these antibiotics. These are called Carbapenem-resistant Enterobacteriaceae. Carbapenem-resistant Enterobacteriaceae testing is considered to be a gram-negative pathogen testing. Common gram-negative pathogens include Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumonia, Enterobacter aerogenes and Acinetobacterbaumannii. These gram-negative pathogens can be mediated and treated by transferable carbapenemase-encoding genes.