Hotspot mutations and ColE1 plasmids contribute to the fitness of Salmonella Heidelberg in poultry litter
Fig 6
Acquisition of ColE1 plasmids was associated with decreased susceptibility to aminoglycosides and fosfomycin.
(a) Multiple alignment of conserved N-terminal residues for aminoglycoside acetyltransferase (AAC-6’) genes encoded in the S. Heidelberg (SH-2813) chromosome and ColE1-6kb plasmid from this study, and AAC-6’ genes with known resistance phenotype. (b) Corresponding neighbor-joining tree of aligned AAC-6’ protein sequences. (c) Inhibition zone diameter (mm) distributions for evolved strains and selected antimicrobial drugs. SH-2813 (n = 27) and SH-116 (n = 18) isolates tested were recovered after 0 and 14 days of microevolution in PL. A decrease in inhibition zone corresponds to a decrease in susceptibility to selected antibiotic.