Naslov
Molecular typing of staphylococcus aureus

Autori
Kalenić, Smilja ; Budimir, Ana ; Plečko, Vanda

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
Fifth congress of the International Federation of Infection Control : abstracts / - Zagreb, 2004, 39-40

Skup
Congress of the International Federation of Infection Control (1 ; 2004)

Mjesto i datum
Poreč, Hrvatska, 09.10.2004. - 12.10.2004

Vrsta sudjelovanja
Pozvano predavanje

Vrsta recenzije
Domaća recenzija

Ključne riječi
molecular typing; S.aureus

Sažetak
Staphylococcus aureus has been recognized as an important nosocomial pathogen causing wide range of hospital acquired infections. Today's problem is meticillin resistance in S.aureus strains, which is the major problem of hospital epidemiology in some areas of the world. Methicillin-resistance in Staphylococcus aureus isolates first appeared in 1960s, by acquisition of the methicillin resistance gene mecA, which is carried by the staphylococcal cassette chromosome mec (SCCmec). In order to find out wheter the particular strains in the hospital outbreak are clonaly related or not, and to reveal the source and routes of transmission, it is necessary to perform typing of strains involved. Different typing methods have been developped for the discrimination of MRSA isolates, allowing to establish effective preventive measures and improve the understanding of MRSA epidemiology. Phenotyping methods Drug susceptibility and phage profile were two phenotypic approaches, although resistance profiles changed over time and many isolates became indistinguoshable because they are multiresistant, often susceptible only to vancomycin. Many isolates are nontypable by phage typing and the interpretation of results requires great expertise. Genotyping methods A/Image-based Among numerous genotyping methods (plasmid profile analysis, REA, RFLP and Southern blotting /ribotyping, binary typing/, AP-PCR, Rep-PCR, RAPD), PFGE (pulse field gel electrophoresis) remains now a gold standard with good reproducibility, discriminatory power, relativly easy to perform, especially for smaller hospital outbreaks. The method has been recently standardised in Europe (HARMONY). Most above mentioned genotyping methods are able to distinguish clonal spread from unrelated isolates when applied in local epidemiological investigation, but they have limited value when questions about development and evolution of strains have to be answered. B/Sequence-based MLST (Multilocus Sequence Typing) method is objective, accurate, and suitable for database storage and software analysis and for its ability to address long-term global epidemiological investigations where the isolates have had substantial time to diversify. However, MLST is not always suitable for outbreak strains typing, because the typing target (houskeeping gens) do not change rapidly, so sometimes strains from an outbreak can be indistinguishable with MLST. Moreover, MLST is labor-intensive, time consuming, and costly to use routinely in a clinical setting. Genotyping methods A/Image-based Among numerous genotyping methods (plasmid profile analysis, REA, RFLP and Southern blotting /ribotyping, binary typing/, AP-PCR, Rep-PCR, RAPD), PFGE (pulse field gel electrophoresis) remains now a gold standard with good reproducibility, discriminatory power, relativly easy to perform, especially for smaller hospital outbreaks. The method has been recently standardised in Europe (HARMONY). Most above mentioned genotyping methods are able to distinguish clonal spread from unrelated isolates when applied in local epidemiological investigation, but they have limited value when questions about development and evolution of strains have to be answered. B/Sequence-based MLST (Multilocus Sequence Typing) method is objective, accurate, and suitable for database storage and software analysis and for its ability to address long-term global epidemiological investigations where the isolates have had substantial time to diversify. However, MLST is not always suitable for outbreak strains typing, because the typing target (houskeeping gens) do not change rapidly, so sometimes strains from an outbreak can be indistinguishable with MLST. Moreover, MLST is labor-intensive, time consuming, and costly to use routinely in a clinical setting. The analysis of variable-number tandem repeats (VTNR) is a new genotyping method, and two targets have been studied as a genotyping tools: a 24-bp repeat unit in the 3' region of protein A (spa) and an 81 bp repeat unit in the 5' region of the coagulase (coa) gene in S. aureus. It was found that in evolutionary studies strains should be characterized by a combination of different typing methods, namely PFGE, MLST, VNTR and SCCmec typing.

Izvorni jezik
Engleski

Znanstvena područja
Temeljne medicinske znanosti

POVEZANOST RADA