Serratia marcescens is an important cause of healthcare-associated infections (HAIs) that may cause outbreaks, especially in intensive care units (ICUs). It is one of the most common bacteria with chromosomally-encoded inducible AmpC β-lactamases and may acquire plasmid-mediated extended-spectrum β-lactamase (ESBL) genes. Thus, it can develop resistance to many β-lactam antibiotics, leading to treatment failure if these enzymes are not detected [1].