Guadalupe Patricia Macías Farrera, Esvieta Tenorio Borroto, Fabiola Rivera Ramírez, Juan Carlos Vázquez Chagoyán, Martín Talavera Rojas, Gilberto Yong Angel and Roberto Montes de Oca Jimenez Pages 5079 - 5084 ( 6 )
Background: The emergence of reduced susceptibility to fluoroquinolones among Salmonella enterica serotype Typhimurium isolates leading to clinical failure of treatment poses a great therapeutic challenge.
Methods: The current study is focused on the evaluation of the minimum inhibitory concentration (MIC) of quinolones in 29 Salmonella typhimurium of 86 Salmonella spp. strains, obtained from pigs from the State of Mexico. The MIC was performed with the Kirby-Bauer method. On the other hand, the GyrA gene was sequenced. The present study was undertaken to describe the resistance profiles and fluoroquinolone resistance mechanism of Salmonella Typhimurium.
Results: The DNA sequence of the gyrA genes from Salmonella enterica serovar typhimurium revealed strong similarity between gyrA and its counterpart in Escherichia coli. The sequencing of quinolone resistance-determining region (QRDR) of the gyrA gene showed the presence of mutation at either S83 or at D87 in almost all the Salmonella typhimurium isolates.
Conclusion: This mutation, although phenotypically expressed as decreased susceptibility to fluoroquinolones goes undetected by the disk diffusion method using the present method of Kirby-Bauer. Hence, it can increase morbidity and mortality due to delay in appropriate antibiotic treatment.
Drug resistance, gyrase A, S. typhimurium, quinolones, bioinformatics.
, , , , , , Center for Research and Advanced Studies in Animal Health, Faculty of Veterinary Medicines and Animal Husbandry, Autonomous University of Mexico State, Km 15.5 Autopista de cuota Toluca - Atlacomulco; Toluca, Estado de México, México, 50200.