Zróżnicowanie typów spa i kaset SCCmec u klinicznych szczepów Staphylococcus aureus opornych na metycylinę izolowanych w ośrodkach regionu gdańskiego
[Differentiation of spa types and staphylococcal cassette chromosome mec (SCCmec) in clinical methicillin-resistant Staphylococcus aureus isolated in medical sites of Gdańsk region]

Streszczenie.

Dokonano oceny zróżnicowania szczepów MRSA izolowanych od pacjentów ośrodków medycznych regionu gdańskiego, w oparciu o wyniki typowania genu spa i kaset SCCmec, z uwzględnieniem profili lekooporności. W badanej populacji najczęściej występowały szczepy z kasetą SCCmec II (46,7%), w większości reprezentujące typy spa t151 (51,4%) i t003 (34,3%), na ogół oporne nie tylko na antybiotyki beta-laktamowe, ale także na erytromycynę, klindamycynę i norfloksacynę (82,8%), przy czym zdecydowanie częściej izolowano je od pacjentów ośrodków szpitalnych niż ambulatoryjnych. Szczepy SCCmec IV, stanowiące większość w ośrodkach ambulatoryjnych (68,8%), najczęściej reprezentowały typ t437 (41,4%) i często występowały w ośrodkach szpitalnych.

Abstract.

Introduction: Methicillin-resistant Staphylococcus aureus bacteria are one of the key etiological factors of hospital-acquired and community-acquired infections. MRSA strains have an ability of causing a broad spectrum infections: from a relatively mild skin infections to severe life-threatening systemic infections. They are haracterized by multi-drug resistance, virulence of a number of factors, may clonally spread within the hospitals and between hospitals.Methods: The study embraced a number of 75 isolates of MRSA isolated from patients of 7 medical sites of the Gdansk region within the period of six months (June to December 2013). Strains have derived from various clinical materials, both of hospitalized patients (n=59) and outpatient (n=16). The isolates were tested for the susceptibility to antimicrobial agents accordance with the guidelines EUCAST. To estimate of the variability of occurrence of S. aureus clones used were standard spa gene, consisting in the amplified polymorphic region of the X gene encoding the protein A gene (spa). After receiving the results, a spa types were identified using international database Ridom Spa Server (www.spaserver.ridom.de). To determine the polymorphism cassette carrying the mecA gene from MRSA strains, used typing five major chromosomal cassette SCCmec (I-V) by multiplex PCR. Results: MRSA population genetic analysis carried out on the basis of typing SCCmec cassettes and spa gene has showed a predominance of strains with SCCmec type II casette (46.7%) and SCCmec IV casette (38.7%). Less frequently detected were strains containing SCCmec I cassette (12.0%) and SCCmec III cassette (2.6%). Spa typing revealed the presence of 13 gene types in MRSA. The most frequently observed spa types were: t151 (24.0%), t003 (16.0%) in strains of the SCCmec II cassette and t437 (16.0%) and t008 (14.8%) in the isolates with SCCmec cassette IV, whereas staphylococcus with the type of spa t011 (12.0%) had SCCmec cassette I. Conclusions: In our population most frequent strains cassette SCCmec II (46.7%), in most representing types of spa t151 (51.4%) and t003 (34.3%), generally resistant not only to β-lactam antibiotics, but as erythromycin, clindamycin and norfloxacin (82.8%), the more frequently they were isolated from patients than a hospital outpatient centers. The strains SCCmec IV that represent the majority of outpatient centers (68.8%), the most represented type t437 (41.4%) and often occurred in hospital centers.