This paper characterizes several beta-lactamases, including TEM-1, SHV-1, CTX-M-15, and NDM-1, which confer resistance to various beta-lactam antibiotics. It also identifies erm(B) and mef(A) as mechanisms of macrolide, lincosamide, and streptogramin B resistance. Additionally, aadA1 and aac(6')-Ib are noted for aminoglycoside resistance, while catA1 and floR contribute to chloramphenicol resistance. The vanA gene is associated with glycopeptide resistance, and mcr-1 is linked to polymyxin resistance.