Master Aminoglycosides with Picmonic for Medicine

This aminoglycoside antibiotic is used for gram negative infections such as Pseudomonas and Proteus, but it is not used for Neisseria or Legionella. It can cause ototoxicity and nephrotoxicity, which limits its use clinically. It is not given orally due to its lack of absorption from the small intestine. It is heat stable and is often used to coat surgical implants and tools.

Neomycin is a popular topical aminoglycoside antibiotic. It is highly ototoxic and nephrotoxic and subsequently is not used as a systemic treatment. Since it is not absorbed by the intestine, it has been incorporated to treat hepatic encephalopathy by eliminating ammonia producing bacteria in the intestine. It is also used to reduce the risk of infection during intestinal surgery by eliminating intestinal bacteria.

This aminoglycoside is mainly used for Pseudomonas, Enterobacter, and Serratia infections, but like the other aminoglycosides, it can cause nephrotoxicity and ototoxicity. This drug cannot be given orally and dosing should be carefully monitored in patients with renal failure.

This is another aminoglycoside antibiotic used for gram negative infections. It is better than gentamicin when it comes to treating pseudomonal infections of the lung. It also cannot be given orally, but has a special application as an ophthalmic solution (Tobrex) for bacterial conjunctivitis. Just like other aminoglycosides, tobramycin also causes ototoxicity and nephrotoxicity.

This was the first aminoglycoside discovered and was used for Mycobacterium tuberculosis infections. This antibiotic is now occasionally used for endocarditis, Yersinia pestis infestation and tuberculosis. Just like other aminoglycosides, streptomycin also causes ototoxicity and nephrotoxicity.

Unlike bacteriostatic agents, which simply stop bacteria from reproducing, bactericidal agents actually cause active bacterial cell death.

Aminoglycosides bind to the 30S prokaryotic ribosomal subunit and inhibit bacterial protein synthesis. This is performed by inhibiting formation of the initiation complex required to translate bacterial mRNA.

Aminoglycosides bind to the 30S prokaryotic ribosomal subunit and are known to interfere with the proofreading process, increasing the error rate during synthesis and misreading of bacterial mRNA. This commonly leads to premature termination of protein synthesis.

Aminoglycosides require oxygen for uptake into the bacterial organism. As such, these antibiotics are ineffective against anaerobes, which do not require oxygen for proliferation.

Enzymatic modification by transferase enzymes is the most common mechanism of aminoglycoside resistance. The genes encoding for these modifying enzymes are typically found on plasmids and transposons. There are three types of aminoglycoside modifying enzymes, including acetyltransferases, phosphotransferases and adenyltransferases.

Acetylation refers to the transfer of an acetyl group on an amino group and this form of enzymatic modification can lead to aminoglycoside resistance.

Phosphotransferases catalyze ATP-dependent phosphorylation of a hydroxyl group and this form of enzymatic modification can lead to aminoglycoside resistance.

Adenyltransferases catalyze ATP-dependent adenylation of hydroxyl groups and this form of enzymatic modification can lead to aminoglycoside resistance.

Aminoglycosides are typically used for aerobic gram-negative rod infections, including Pseudomonas and Enterobacter. The most frequent use of these antibiotics include empiric therapy for serious infections, including septicemia, complicated intra-abdominal infections, UTIs, and nosocomial URIs.

Aminoglycosides are sometimes used in conjunction with beta-lactam antibiotics in streptococcal infections due to their synergistic effects, especially in the treatment of endocarditis. One of the most frequently used combinations is ampicillin and gentamicin.

Cephalosporins and aminoglycosides demonstrate a synergistic nephrotoxic interaction when used in conjunction. Therefore, this drug combination should be avoided unless clinically required and kidney function should be monitored throughout the treatment course.

Aminoglycosides and loop diuretics, like furosemide, demonstrate a synergistic ototoxic interaction when used in conjunction. Therefore, this drug combination should be avoided when possible.

Aminoglycosides are known teratogens and are in pregnancy category D, meaning there is positive evidence of human fetal risk based on data from studies in humans. Teratogens are agents that cause a defect or malformation in the development of the embryo or fetus. Aminoglycosides are especially associated with causing hearing deficits.