Tobramycin resistant bacteria

Gentamicin and tobramycin are equally effective. Tobramycin has slightly better MICs to Pseudomonas. Amikacin generally is reserved for multi-drug resistant bacteria. Typically used as a short course of therapy followed by a switch to an oral agent. 

With nebulized tobramycin the introduction or selection of resistant bacteria is relatively rare but is a matter of concern (41). 

The purpose of this study was to adopt a systematic approach to optimize formulation and to characterize the properties of tobramycin-PMMA implants. Tobramycin was selected as it is active against both Gram-positive and Gram-negative bacteria, including gentamicin-resistant Pseudomonas. The specific aims of the study were... 

Tobramydtt. The antibacterial activity and pharmacokinetic properties of tobramycin resemble those of gentamicin, and the therapeutic uses of tobramycin are essentially identical to those for gentamicin. Although some bacteria are resistant to both gentamicin and tobramycin, it is impredictable in individual strains. Amikacin is usually effective for infections caused by organisms resistant to both gentamicin and tobramycin. 

Netilmicin is a semisynthetic aminoglycoside which is active against some strains of bacteria that resist gentamicin and tobramycin evidence suggests that it may be less oto- and nephrotoxic. 

The chronic use of antibiotics to suppress bacteria in CF is controversial because antibiotic resistance may be induced or enhanced. Suppressive therapy is prescribed with the intention of prolonging the time between acute exacerbations and to slow the rate of progression of lung disease. Although attractive intuitively, this practice is not supported by well-designed clinical trials. Moreover, the practice of routine, quarterly administration of intravenous courses of antibiotics used at some European centers still lacks proof of efficacy. Aerosolized tobramycin (TOBI) daily for 1 to 2 months has been shown to eradicate P. aeruginosa from the airways of recently infected patients with CF. 

Bacteria develop resistance to aminoglycosides by producing enzymes that chemically inactivate aminoglycosides or by decreasing drug uptake into the cell. Amikacin is least sensitive to these modifying enzymes, followed by tobramycin, gentamicin and kanamycin. 

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