Hybrid genome assembly and annotation of multidrug-resistant Staphylococcus aureus genotype ST672-SCCmec type IVd (2B).

OBJECTIVES

The emergence of multidrug-resistant Staphylococcus aureus strains is mainly mediated by mobile genetic elements, such as Staphylococcal Cassette Chromosome mec (SCCmec). Currently, SCCmec elements in S. aureus are classified into 15 types, with type IV being the most common in hospital and community-associated methicillin-resistant S. aureus. Among different subtypes of SCCmec type IV strains (IVa-IVn), the complete genome sequence of the SCCmec IVd (2B) subtype is still lacking. Here, we report the complete genome sequence of multidrug-resistant S. aureus SCCmec typeIVd (2B) isolate, S. aureus S145.

METHODS

Staphylococcus aureus S145 was subjected to phenotypic and genotypic characterization. The whole-genome sequencing of S145 was performed using a hybrid-genome approach. The antibiotic-resistance genes were detected and compared with 112 publicly available S. aureus genomes.

RESULTS

We obtained a complete genome of S145 with 2.7 Mbp length, Guanine-Cytosine (GC) content of 32.8%, and 2,548 protein-coding regions with 79 virulence factors and 90 antibiotic resistance genes. The S145 has ∼17-kb SCCmec, which encodes genes such as mecA, mecR1, ccrA2B2, and SCCmec IVd (2B) subtype gene CG002. We detected a ∼30-kb multidrug-resistant plasmid with eight antibiotic-resistant genes forming three clusters. Cluster1 encoded for penicillin (blaI-blaZ-blaR1), Cluster2 for aminoglycoside-streptothricin (aph(3')-IIIa-sat4-ΔANT(6)-Ia), and Cluster3 for macrolides (msr(A)-mph(C)) resistance genes. Comparative analysis of Cluster1-Cluster3 revealed that the genetic organization of these clusters resembles resistance genes present in plasmids of USA300 S. aureus SCCmec type IVa strains.

CONCLUSION

Here, we report the complete genome sequence of S. aureus SCCmec IVd (2B) that can be used as a reference genome for further comparative genomic analysis.