β-Lactam antibiotics are one of the most relevant drug classes of antibacterial agents worldwide. The discovery and the market of first β-lactam antibiotic (Penicillin G) is a symbolic landmark of modern chemotherapy. Since then, several other β-lactam antibiotics have been introduced in the therapy, revolutionizing the treatment of bacterial infections. Their antibacterial efficacy has been kept in check by the emergence of bacterial resistance. Among the resistance mechanisms, the expression of β-lactamase enzymes is one of the most studied and prevalent. The combined use of beta-lactamase inhibitors with broad spectrum activity β-lactam antibiotics has been an effective strategy to circumvent the resistance issue. This review discusses, with a focus on structural aspects, the different classes of beta-lactam antibiotics (penicillins, cephalosporins, carbapenems, monobactams and penems) in light of their stability, sensitivity to β-lactamases, mechanism of action and spectrum of antimicrobial activity. β-Lactamase inhibitors (structurally correlated and non-correlated to the β-lactam system) and their proposed inhibition mechanisms are also discussed.

β-内酰胺抗生素是全球最相关的抗菌药物之一。第一种β-内酰胺抗生素（青霉素G）的发现和市场是现代化学疗法的标志性里程碑。从那时起，其他几种β-内酰胺类抗生素已被引入治疗，彻底改变了细菌感染的治疗方法。细菌耐药性的出现一直抑制着它们的抗菌功效。在抗性机制中，β-内酰胺酶的表达是研究最广泛的一种。β-内酰胺酶抑制剂与广谱活性的β-内酰胺类抗生素的联合使用已成为规避耐药性问题的有效策略。本文以结构方面为重点，讨论了不同类别的β-内酰胺类抗生素（青霉素，鉴于它们的稳定性，对β-内酰胺酶的敏感性，作用机理和抗菌活性谱，考虑到头孢菌素，碳青霉烯类，单bactams和Penems）。还讨论了β-内酰胺酶抑制剂（与β-内酰胺系统结构相关和不相关）及其提议的抑制机制。