The spa typing method is based on sequencing of the polymorphic X region of the protein A gene (spa), present in all strains of Staphylococcus aureus. The X region is constituted of a variable number of 24-bp repeats flanked by well-conserved regions. This single-locus sequence-based typing method combines a number of technical advantages, such as rapidity, reproducibility, and portability. Moreover, due to its repeat structure, the spa locus simultaneously indexes micro- and macrovariations, enabling the use of spa typing in both local and global epidemiological studies. These studies are facilitated by the establishment of standardized spa type nomenclature and Internet shared databases.
"This single-locus sequence-based typing method combines a number of technical advantages, such as rapidity, reproducibility, and portability. Moreover, because of its repeat structure, the spa locus simultaneously indexes micro- and macrovariations, enabling the use of spa typing in both local and global epidemiological studies . The current terminology to describe a lineage is based on multilocus sequence typing (MLST) clonal complexes (CCs). "
[Show abstract][Hide abstract] ABSTRACT: Multidrug resistant strains of Staphylococcus aureus are a major cause of skin and soft tissue infections requiring the development of novel and alternative therapeutic options. Photodynamic oxidation is the cornerstone of antimicrobial photodynamic therapy (aPDT) involving the combined use of light and a photosensitizer, which, in the presence of oxygen, originates cytotoxic species capable of oxidizing biological molecules and leads to inactivation of target cells. We have previously shown that susceptibility to aPDT differs significantly across S. aureus isolates and could be associated with several genetic elements. However, the effect of the photodynamic process regarding the S. aureus genetic background has never been reported. We have compared the genetic backgrounds of the strains (SCCmec types, spa types and main clonal complexes) with respect to their susceptibility to protoporphyrin IX-mediated photodynamic inactivation. SCCmec typing revealed no differences in response to photoinactivation. However, detection of spa types and clonal complexes clustered the studied population of MRSA strains according to their response to photodynamic oxidation. Clonal complex 1 (CC1) accounted for elevated resistance and CC30 (ST36) for susceptibility to photoinactivation. Moreover, spa typing identified isolates resistant (t032) and susceptible to photodynamic oxidation (t051, t015). The very tight association between clonal lineages and response to photodynamic inactivation indicates the important role of genetic background for aPDT efficacy. These results make a case for the development of a diagnostic tool with the predictive value of aPDT efficacy according to an identified genetic background of S. aureus isolates.
Electronic supplementary material
The online version of this article (doi:10.1007/s10096-013-1987-5) contains supplementary material, which is available to authorized users
European Journal of Clinical Microbiology 10/2013; 33(4). DOI:10.1007/s10096-013-1987-5 · 2.67 Impact Factor
"for SCCmec typing, SRL and Type-Net (in The Netherlands only)] have been developed to handle the data. Specifically, spa typing via the Ridom server   provides a standard universal and worldwide nomenclature together with integral quality control, allowing only sequences of excellent quality to be synchronised with the spa server . Different spa types related to each other are analysed via the BURP (Based Upon Repeat Patterns) algorithm, showing good congruency with MLST CCs . "
[Show abstract][Hide abstract] ABSTRACT: This article reviews recent findings on the global epidemiology of healthcare-acquired/associated (HA), community-acquired/associated (CA) and livestock-associated (LA) meticillin-resistant Staphylococcus aureus (MRSA) and aims to reach a consensus regarding the harmonisation of typing methods for MRSA. MRSA rates continue to increase rapidly in many regions and there is a dynamic spread of strains across the globe. HA-MRSA is currently endemic in hospitals in most regions. CA-MRSA clones have been spreading rapidly in the community and also infiltrating healthcare in many regions worldwide. To date, LA-MRSA is only prevalent in certain high-risk groups of workers in direct contact with live animals. CA-MRSA and LA-MRSA have become a challenge for countries that have so far maintained low rates of MRSA. These evolutionary changes have resulted in MRSA continuing to be a major threat to public health. Continuous efforts to understand the changing epidemiology of S. aureus infection in humans and animals are therefore necessary, not only for appropriate antimicrobial treatment and effective infection control but also to monitor the evolution of the species. The group made several consensus decisions with regard to harmonisation of typing methods. A stratified, three-level organisation of testing laboratories was proposed: local; regional; and national. The functions of, and testing methodology used by, each laboratory were defined. The group consensus was to recommend spa and staphylococcal cassette chromosome mec (SCCmec) typing as the preferred methods. Both are informative in defining particular strain characteristics and utilise standardised nomenclatures, making them applicable globally. Effective communication between each of the different levels and between national centres was viewed as being crucial to inform and monitor the molecular epidemiology of MRSA at national and international levels.
International journal of antimicrobial agents 01/2012; 39(4):273-82. DOI:10.1016/j.ijantimicag.2011.09.030 · 4.30 Impact Factor
"In the current study, the LAMP method was applied to detect the mecA gene in both cultivated cells and clinical samples. In addition, the method was used for detection of spa, the gene for protein A, unique to S. aureus (Hallin et al. 2009). "
[Show abstract][Hide abstract] ABSTRACT: To develop a detection assay for staphylococcal mecA and spa by using loop-mediated isothermal amplification (LAMP) method.
Staphylococcus aureus and other related species were subjected to the detection of mecA and spa by both PCR and LAMP methods. The LAMP successfully amplified the genes under isothermal conditions at 64 degrees C within 60 min, and demonstrated identical results with the conventional PCR methods. The detection limits of the LAMP for mecA and spa, by gel electrophoresis, were 10(2) and 10 cells per tube, respectively. The naked-eye inspections were possible with 10(3) and 10 cells for detection of mecA and spa, respectively. The LAMP method was then applied to sputum and dental plaque samples. The LAMP and PCR demonstrated identical results for the plaque samples, although frequency in detection of mecA and spa by the LAMP was relatively lower for the sputum samples when compared to the PCR methods.
Application of the LAMP enabled a rapid detection assay for mecA and spa. The assay may be applicable to clinical plaque samples.
The LAMP offers an alternative detection assay for mecA and spa with a great advantage of the rapidity.
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