Chromosomally mediated multidrug resistance in Salmonella typhimurium is generally attributed to the overexpression of the acrAB locus and the mutation in topoisomerase genes.

• AcrAB外流泵系统的过度表达和拓扑异构酶基因突变是导致鼠伤寒沙门菌产生多重耐药性 (MAR)的重要原因。