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Penicillin molecules are small enough to pass through the spaces of glycoproteins in the cell wall. For this reason Gram-positive bacteria are very susceptible to penicillin (as first evidenced by the discovery of penicillin in 1928 [46]). [47] Penicillin, or any other molecule, enters Gram-negative bacteria in a different manner. The bacteria ...
Antimicrobial use has been common practice for at least 2000 years. Ancient Egyptians and ancient Greeks used specific molds and plant extracts to treat infection. [5]In the 19th century, microbiologists such as Louis Pasteur and Jules Francois Joubert observed antagonism between some bacteria and discussed the merits of controlling these interactions in medicine. [6]
Antibiotics with less reliable but occasional (depending on isolate and subspecies) activity: occasionally penicillins including penicillin, ampicillin and ampicillin-sulbactam, amoxicillin and amoxicillin-clavulnate, and piperacillin-tazobactam (not all vancomycin-resistant Enterococcus isolates are resistant to penicillin and ampicillin)
For example, antibacterial selection for strains having previously acquired antibacterial-resistance genes was demonstrated in 1943 by the Luria–Delbrück experiment. [85] Antibiotics such as penicillin and erythromycin, which used to have a high efficacy against many bacterial species and strains, have become less effective, due to the ...
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.
Material surfaces can exhibit bactericidal properties because of their crystallographic surface structure. Somewhere in the mid-2000s it was shown that metallic nanoparticles can kill bacteria. The effect of a silver nanoparticle for example depends on its size with a preferential diameter of about 1–10 nm to interact with bacteria. [3]
A strong research focus has been placed on triggering production of excessive reactive oxygen species (ROS) using nanoparticles injected into bacterial cells. The presence of excessive ROS can stress the cell structure leading to damaged DNA/RNA, decreased membrane activity, disrupted metabolic activity, and harmful side reactions generating chemicals such as peroxides.
Tetracyclines are generally used in the treatment of infections of the urinary tract, respiratory tract, and the intestines and are also used in the treatment of chlamydia, especially in patients allergic to β-lactams and macrolides; however, their use for these indications is less popular than it once was due to widespread development of resistance in the causative organisms.