Detection and quantification of Staphylococcus aureus genes and mobile genetic elements within bacteriophage particles by qPCR
| Authors | |
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| Year of publication | 2012 |
| Type | Conference abstract |
| MU Faculty or unit | |
| Citation | |
| Description | Rapid evolution of Staphylococcus species contributes to substantial variability of strains and formation of novel clones and is facilitated by the acquisition of new genes through horizontal gene transfer (HGT). The newly acquired genes responsible for virulence and ATB resistance are rapidly disseminated in the staphylococcal population. It is widely accepted that temperate bacteriophages play a major role in this process and contribute to spread of mobile genetic elements (MGE) including SCCmec element. Methicillin resistant S. aureus strains (MRSA) represent a significant medical problem. In the present day, 11 different types of SCCmec element are described, which carry mecA gene responsible for methicillin resistance, but the transfer mechanisms and evolution of SCCmec element are still discussed. In this study, we developed and optimized the technique for detection and quantification of S. aureus bacterial genes directly within the phage particles via qPCR. The packaging frequencies of 12 different bacterial genes including genes localized on staphylococcal cassette chromosome mec (SCCmec type I), staphylococcal pathogenicity island SaPI1 and genomic islands were compared. Non-parametric statistical analysis showed that transducing staphylococcal bacteriophages 11, 80 and 80alpha of serogroup B, in contrast to serogroup A bacteriophage 81, efficiently package selected chromosomal genes localized in 4 various loci of the chromosome and genes carried on MGE like SCCmec type 1, SaPI1, genomic islands Saalpha and Sabeta, and plasmids with various frequency. Bacterial gene copy number per ng (CG/ng) of DNA isolated from phage particles was established for all 12 analysed genes. The new and crucial finding that serogroup B bacteriophages can package concurrently ccrA1 and mecA localized on SCCmec type I into their capsids indicates that generalized transduction plays an important role in the evolution and emergence of novel MRSA clones. |
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