Escherichia coli is a Gram-negative, rod-shaped bacterium, responsible for 90% of all community-acquired infections and 50% of hospital-acquired infections, with opportunistic infections found in intensive care unit (ICU) patients. The β-lactam antibiotics, which inhibit cell wall synthesis, are known for their high efficacy and broad-spectrum activity. They also have low toxicity and provide long-term effects, making them widely used drugs against Gram-negative bacteria. Bacteria develop resistance to β-lactams primarily through the expression of hydrolytic enzymes, called β-lactamases, which are divided into serine β-lactamases (Classes A, C, and D) and metallo-β-lactamases (Class B), based on their molecular mechanism. This study aimed to clarify the mechanism of action of β-lactams against Gram-negative bacilli and to emphasize the multidrug resistance of cephalosporins and carbapenems to E. coli.
