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One example of Class IIa bacteriocin is pediocin PA-1. [13] The class IIb bacteriocins (two-peptide bacteriocins) require two different peptides for activity. One such an example is lactococcin G, which permeabilizes cell membranes for monovalent sodium and potassium cations, but not for divalent cations. Almost all of these bacteriocins have a ...
β-Lactam antibiotics are indicated for the prevention and treatment of bacterial infections caused by susceptible organisms. At first, β-lactam antibiotics were mainly active only against gram-positive bacteria, yet the recent development of broad-spectrum β-lactam antibiotics active against various gram-negative organisms has increased their usefulness.
Antimicrobial peptides have been demonstrated to kill Gram negative and Gram positive bacteria, [1] enveloped viruses, fungi and even transformed or cancerous cells. [2] Unlike the majority of conventional antibiotics it appears that antimicrobial peptides frequently destabilize biological membranes , can form transmembrane channels , and may ...
Phages destroy bacterial cell walls and membrane through the use of lytic proteins which kill bacteria by making many holes from the inside out. [272] Bacteriophages can even possess the ability to digest the biofilm that many bacteria develop that protect them from antibiotics in order to effectively infect and kill bacteria.
Other forms of antibiotic-associated harm include anaphylaxis, drug toxicity most notably kidney and liver damage, and super-infections with resistant organisms. Antibiotics are also known to affect mitochondrial function, [126] and this may contribute to the bioenergetic failure of immune cells seen in sepsis. [127]
Polymyxin antibiotics are relatively neurotoxic and nephrotoxic, so are usually used only as a last resort if modern antibiotics are ineffective or are contraindicated. Typical uses are for infections caused by strains of multiple drug-resistant Pseudomonas aeruginosa or carbapenemase -producing Enterobacteriaceae .
Bactericidal antibiotics kill bacteria; bacteriostatic antibiotics slow their growth or reproduction. Bactericidal antibiotics that inhibit cell wall synthesis: the beta-lactam antibiotics ( penicillin derivatives ( penams ), cephalosporins ( cephems ), monobactams , and carbapenems ) and vancomycin .
Drug, toxin, or chemical resistance is a consequence of evolution and is a response to pressures imposed on any living organism. Individual organisms vary in their sensitivity to the drug used and some with greater fitness may be capable of surviving drug treatment.