Sterilization with generic vancomycins of Rattus norvegicus Sprague Dawley hearts from experimental endocarditis by E. faecalis ATCC 29212

Abstract

The use of generic antibiotics creates suspicion regarding the innovator. In many countries, especially those in the developing world, these drugs are abundant, due to the cost of the innovator acquisition. However, there are many therapeutic failures that doctors report with its use. The objective of this work was to evaluate the efficacy of generic vancomycin, to sterilize the hearts of Rattus norvegicus Sprague Dawley from experimental endocarditis caused with the vancomycin sensitive strain E. faecalis ATCC 29212. Adult male specimens of Rattus norvegicus Sprague-Dawley were used; they were inoculated with the E. faecalis ATCC 29212 strain (1.5 x 108 CFU / ml) intravenously, to produce an experimental endocarditis. The control rat was sacrificed 48 hours after bacterial inoculation. The remaining five rats, also inoculated with E. faecalis ATCC 29212, received the treatment for five days intramuscularly, one rat for each vancomycin under study. Generic vancomycins were from Behrens, Celovan, Fada Pharma, Vancomax, and Vancocyn. To verify the sterility of the hearts with the generic vancomycin, they were placed in BHI broth, at 35°C. Following incubation, E. faecalis ATCC 29212 colony growth was verified and CFUs were counted per gram of cardiac tissue. The control rat had a bacterial growth of 1.8 x 1012 CFU/g of cardiac tissue. The rats treated with Behrens, Vancocyn and Celovan sterilized the hearts, while those treated with Vancomax and Fada Pharma showed bacterial growth (2.8 x 1012 CFU/g and 4.2 x 1010 CFU/g, respectively). In conclusion, the pharmaceutical equivalence of a generic vancomycin, with respect to the innovator, does not guarantee therapeutic equivalence. More studies need to be done on generic antibiotics to ensure their human clinical use.