Resistance to aminoglycosides

Biochemical mechanism of resistance to aminoglycosidic antibiotics, H. Umezawa, Adv. Carbohydr. Chem. Biochem., 30 (1974) 183-225. 

Genes encoding 3-iV-aminoglycoside acetyltransferases confer resistance to aminoglycosides... 

Anaerobes also are resistant to aminoglycosides because of decreased transport into the bacterial cytosol. Combining an aminoglycoside with an antibiotic that disrupts the bacterial cell wall can overcome this natural resistance. 

All aminoglycosides are given parenterally and are rapidly bactericidal. They interfere with assembly of the functional ribosomal apparatus or cause the 30S subunit of the complete ribosome to misread the genetic code. Anaerobes lack the oxygen-dependent system that is responsible for transporting the antibiotics across the cytoplasmic membrane, therefore, strictly anaerobic organisms are resistant to aminoglycosides. 

Interaction between -lactamase and intrinsic resistance Resistance to aminoglycosides Resistance to kanamycins Resistance to neomycins Resistance to streptomycin Resistance to gentamicin Resistance to lividomycin Resistance to tobramycin Resistance to BB-K8 Resistance to chloramphenicoi... 

Amikacin is mainly of value because it is more resistant to aminoglycoside-inactivating bacterial enzymes than is gentamicin. Since it is more costly, amikacin is reserved for treatment of infections with gentamicin-resistant organisms. Peak plasma concentrations should be kept between 20-30 mg/1 and trough concentrations below 10 mg/1. 

A multidrug efflux system that appears to be a major contributor to intrinsic high-level resistance to aminoglycosides and macrolides has been identified in Burkholderia pseudomallei (133). 

In mice, the bacterial neomycin phosphotransferase gene, which confers resistance to aminoglycoside antibiotics, prevented the loss of hair cells after neomycin treatment (142). 

These depend on the fact that bacterial resistance to aminoglycosides (Chapter 13), such as gentamicin, tobramycin, amikacin, netilmicin, streptomycin, spectinomycin, etc. and chloramphenicol is frequently associated with the presence of specific enzymes (often coded for by transmissible plasmids), which either acetylate, adenylylate or phosphory-late the antibiotics, thereby rendering them inactive (Chapter 13). Aminoglycosides may be susceptible to attack by aminoglycoside acetyltransferases... 

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