Complete Genome Sequence of the Type Strain of Macrococcus canis

Macrococcus canis contains recombinogenic methicillin resistance elements and the mecB plasmid found in Staphylococcus aureus

OBJECTIVES

To analyse the genetic context of mecB in two Macrococcus canis strains from dogs, compare the mecB-containing elements with those found in other Macrococcus and Staphylococcus species, and identify possible mobilizable mecB subunits.

METHODS

Whole genomes of the M. canis strains Epi0076A and KM0218 were sequenced using next-generation sequencing technologies. Multiple PCRs and restriction analysis confirmed structures of mecB-containing elements, circularization and recombination of mecB subunits.

RESULTS

Both M. canis strains contained novel composite pseudo (Ψ) staphylococcal cassette chromosome mec (SCCmec) elements. Integration site sequences for SCC flanked and subdivided composite ΨSCCmecEpi0076A (69569 bp) into ΨSCC1Epi0076A-ΨSCCmecEpi0076A-ΨSCC2Epi0076A and composite ΨSCCmecKM0218 (24554 bp) into ΨSCCKM0218-ΨSCCmecKM0218. Putative γ-haemolysin genes (hlgB and hlgC) were found at the 3' end of both composite elements. ΨSCCmecKM0218 contained a complete mecB gene complex (mecIm-mecR1m-mecB-blaZm) downstream of a new IS21-family member (ISMaca1). ΨSCCmecEpi0076A carried a blaZm-deleted mecB gene complex similar to that reported in 'Macrococcus goetzii' CCM4927T. A second mecB gene was found on the 81325 bp MDR plasmid pKM0218 in KM0218. This plasmid contained a complete Tn6045-associated mecB gene complex distinct from that of ΨSCCmecKM0218. pKM0218 was almost identical to the mecB-containing plasmid recently reported in Staphylococcus aureus (overall 99.96% nucleotide identity). Mobilization of mecB within an unconventional circularizable structure was observed in Epi0076A as well as chromosomal plasmid insertion via recombination of mecB operons in KM0218.

CONCLUSIONS

Our findings provide evidence of both the continuing evolution of mecB-containing elements in macrococci and M. canis as a potential source of the mecB-containing plasmid found in staphylococci.

Draft Genome Sequences of the Type Strains of Six Macrococcus Species

We report here the draft genome sequences of Macrococcus bovicus ATCC 51825^T, Macrococcus carouselicus ATCC 51828^T, Macrococcus equipercicus ATCC 51831^T, Macrococcus brunensis CCM4811^T, Macrococcus hajekii CCM4809^T, and Macrococcus lamae CCM4815^T. The availability of the genome sequences of these species will enable cross-species comparison, which could lead to a more comprehensive understanding of organisms of the Macrococcus genus.

We report here the draft genome sequences of Macrococcus bovicus ATCC 51825^T, Macrococcus carouselicus ATCC 51828^T, Macrococcus equipercicus ATCC 51831^T, Macrococcus brunensis CCM4811^T, Macrococcus hajekii CCM4809^T, and Macrococcus lamae CCM4815^T. The availability of the genome sequences of these species will enable cross-species comparison, which could lead to a more comprehensive understanding of organisms of the Macrococcus genus.

Description and Comparative Genomics of Macrococcus caseolyticus subsp. hominis subsp. nov., Macrococcus goetzii sp. nov., Macrococcus epidermidis sp. nov., and Macrococcus bohemicus sp. nov., Novel Macrococci From Human Clinical Material With Virulence Potential and Suspected Uptake of Foreign DNA by Natural Transformation

The genus Macrococcus is a close relative of the genus Staphylococcus. Whilst staphylococci are widespread as human pathogens, macrococci have not yet been reported from human clinical specimens. Here we investigated Gram-positive and catalase-positive cocci recovered from human clinical material and identified as Macrococcus sp. by a polyphasic taxonomic approach and by comparative genomics. Relevant phenotypic, genotypic and chemotaxonomic methods divided the analyzed strains into two separate clusters within the genus Macrococcus. Comparative genomics of four representative strains revealed enormous genome structural plasticity among the studied isolates. We hypothesize that high genomic variability is due to the presence of a com operon, which plays a key role in the natural transformation of bacilli and streptococci. The possible uptake of exogenous DNA by macrococci can contribute to a different mechanism of evolution from staphylococci, where phage-mediated horizontal gene transfer predominates. The described macrococcal genomes harbor novel plasmids, genomic islands and islets, as well as prophages. Capsule gene clusters, intracellular protease, and a fibronectin-binding protein enabling opportunistic pathogenesis were found in all four strains. Furthermore, the presence of a CRISPR-Cas system with 90 spacers in one of the sequenced genomes corresponds with the need to limit the burden of foreign DNA. The highly dynamic genomes could serve as a platform for the exchange of virulence and resistance factors, as was described for the methicillin resistance gene, which was found on the novel composite SCCmec-like element containing a unique mec gene complex that is considered to be one of the missing links in SCC evolution. The phenotypic, genotypic, chemotaxonomic and genomic results demonstrated that the analyzed strains represent one novel subspecies and three novel species of the genus Macrococcus, for which the names Macrococcus caseolyticus subsp. hominis subsp. nov. (type strain CCM 7927T = DSM 103682T), Macrococcus goetzii sp. nov. (type strain CCM 4927T = DSM 103683T), Macrococcus epidermidis sp. nov. (type strain CCM 7099T = DSM 103681T), and Macrococcus bohemicus sp. nov. (type strain CCM 7100T = DSM 103680T) are proposed. Moreover, a formal description of Macrococcus caseolyticus subsp. caseolyticus subsp. nov. and an emended description of the genus Macrococcus are provided.