Whole-genome sequencing of Staphylococcus aureus strain RN4220, a key laboratory strain used in virulence research, identifies mutations that affect not only virulence factors but also the fitness of the strain

Abstract

Staphylococcus aureus RN4220, a cloning intermediate, is sometimes used in virulence, resistance, and metabolic studies. Using whole-genome sequencing, we showed that RN4220 differs from NCTC8325 and contains a number of genetic polymorphisms that affect both virulence and general fitness, implying a need for caution in using this strain for such studies.

Fig. 1.

Graphical mapping of the strain RN4220 contigs onto the strain NCTC8325. The RN4220 contigs are shown on the left-hand side of the circle, while the complete genome sequence of the strain NCTC8325 is shown on the right-hand side. Homologous sequences between the two strains are linked by colored ribbons. The black dots along the NCTC8325 genome sequence indicate the SNP positions, as described in Table S2 in the supplemental material. The three open circles indicate the large regions in NCTC8325 that are deleted in RN4220.