penicillins, cephalosporins, carbapenems, and monobactams, which are, therefore, also called β-lactam antibiotics
What is β-lactam??? A four-membered lactam These antibiotics inhibiting the (A lactam is a cell walls of bacteria cyclic amide),nitrogen atom Cause lethal effect on bacteria is attached to the β-carbon relative to the carbonyl. The β-lactam ring is part of the core structure of several antibiotic families(β- lactam antibiotics), such as:•
Structure of CephalosporinsCephalosporins (red in colour is structure of β-lactam )
Mechanism of actionCephalosporins are All bacterial cells have a cellbactericidal (which means wall that protects themthat they kill bacteria) have Structure of β-lactam canthe same mode of action as detect enzymes which involveother β-lactam antibiotics as in cell wall synthesis.penicillins Then it can inactivating the enzymes thus inhibit formation of cell wall which causes the walls to break down and eventually the bacteria die.
Uses Used to treat a wide variety of bacterial infections, such as respiratory tract infections (pneumonia, strep throat, tonsillitis, bronchitis), skin infections and urinary tract infections
Commonly used for surgicalprophylaxis - prevention ofbacterial infection before,during, and after surgery
Classifications of Cephalosporins Grouped into “generations” based on their spectrum of microbial activity, such as:• 1st generation• 2nd generation• 3rd generation• 4th generation First Chepalosporins designated first generation while later, more advanced cephalosporins were classified as 2nd generation and so on. Each newer generation of cephalosporins has significantly greater gram-negative antimicrobial properties than previous one.
1st generation 2nd generation Moderate Greater gram-negative Treating staphylococcal spectrum while retaining and streptococcal some activity against infections and therefore gram-positive bacteria are alternatives for skin More resistant to β- and soft-tissue infections. lactam, treating upper Example: and lower respiratory Cephaloridine tract infections, sinusitis and otitis media. Cephalothin Active against E. coli, Cephapirin Klebsiella and Proteus Example : Cefaclor Cefoxitin
3rd generation 4th generation Further increased activity Greater resistance to β- against gram-negative lactam than the 3rd organisms generation. Excellent activity against Can cross blood brain most strains of barrier and are effective Streptococcus in meningitis pneumoniae including Example : that have high level Cefepime resistance to penicillin Cefluprenam and N. gonorrhoeae Cefozopran Example: Cefdinir Cefixime