Integron-mediated Multidrug Resistance in a Global Collection of Nontyphoidal Salmonella enterica Isolates
Figure. Minimum spanning trees depicting integron distribution across Salmonella enterica genetic lineages. A) dfrA12/orfF/aadA2; B) dfrA7; C) dfrA1/aadA1; D) arr2/blaOXA30/cmlA5/aadA2. Circles represent unique sequence types (STs). Red circles represent the STs that carried the integron involved in horizontal gene transfer. Numbers in circles represent the ST. Circle size reflects number of isolates in each ST. Pink and green shading indicates closely related groups of isolates. Letters refer to serotypes: B, Brandenburg; C, Cholerasuis; E, Enteriditis; H, Heidelberg; G, Goettingen; I, Isangi; P, Paratyphi A; Z, Schwarzengrund; Y, Stanley; T, Typhimurium. Geographic sources of isolates are as follows: Panel A: ST66, serotype C, Taiwan; ST29, serotype C, Taiwan; ST29, serotype Y, Taiwan; ST96, serotype Z, Denmark and Taiwan; ST19, serotype T, US Centers for Disease Control and Prevention and South Africa; ST15, serotype H, Philippines; Panel B: ST11, serotype E, Uganda and South Africa; ST85, serotype P, Denmark; Panel C: ST334, serotype G, Spain; ST334, serotype B, Spain; ST34, serotype T, Germany; Panel D: ST19, serotype T, South Africa; ST216, ST335, ST336, and ST 337, serotype I, South Africa.