Fitness Costs and Stability of a High-Level Ciprofloxacin Resistance Phenotype in <i>Salmonella enterica</i> Serotype Enteritidis: Reduced Infectivity Associated with Decreased Expression of <i>Salmonella</i> Pathogenicity Island 1 GenesEdel O’Regan, Séamus Fanning, Jonathan G. Frye et al.|Antimicrobial Agents and Chemotherapy|2009Cited by 72