BOCCO JOSE LUIS
Congresos y reuniones científicas
Título:
Continuous Emergence of New CA-MRSA clones from successful MSSA lineages
Autor/es:
EGEA A.L.; GAGETTI P.; BARCUDI D.; FACCONE D.; BOCCO J.L.; CORSO A.; SOLA C.
Lugar:
Córdoba
Reunión:
Congreso; XI Congreso Argentino de Microbiología General (SAMIGE); 2015
Institución organizadora:
Sociedad Argentina de Microbiología General
Resumen:
The emergence of methicillin-resistant Staphylococcus aureus (MRSA) has become an increasing problem worldwide in recent decades causing both hospitalacquired (HA-MRSA) and community-acquired (CA-MRSA) infections. In Argentina CA-MRSA international clones belonging to major lineages coexist in different proportions, such as Sequence Type (ST)5-SCCmec type IVa Clonal Complex 5 (CC5), ST30-IV (CC30), ST97-IV (CC97), ST72-IV (CC8), ST8-IV (USA 300) (CC8) and ST1-IV (CC1).We aimed assess the genetic relationship between CA-MRSA epidemic clones and MSSA strains identified in Argentina to investigate the possible local origin or its spread from other countries of these international CA-MRSA clones A total of 132MSSA clinical isolates collected during Nov-2009 from 66 hospitals (20 provinces and Bs. As. City) were analyzed by S. aureus Protein A (spa) typing, Panton Valentin Leukocidin (PVL), Pulsed Field Gel Electrophoresis (PFGE) and Multilocus SequenceTyping (MLST). Molecular analysis by spa typing; showed 65 different spa types (t) grouped into 12 CC according MLST (%):CC5 (21), CC30 (16), CC1 (15), CC121 (10), CC8 (8), CC45 (8) CC12 (1), CC97 (8), CC25 (4) CC101 (2), CC15 (1), CC88 (1) distributed throughout the country. The proportion of isolates belonging to CC5 (t311 and t002) and CC30: (t012, t021 and t018)differed significantly between North and South of Argentina: 36% and 6% vs. 12% and 32 %, respectively. Based Upon Repeat Pattern (BURP) analysis showed that MRSA (previously analyzed) and MSSA isolates belonging to CC5 shared the same spa type (t311 and t002), suggesting that these were closely related. Contrary, no common spa type was shared between MSSA and MRSA belonging the CC30 (ST30). The remaining CCs also showed a closely genetic relation between the MSSA and MRSA by PFGE type, spa type and Sequence Type , sharing the spa type and the ST, such us: ST72 and t148 (CC8), ST1 and t127 (CC1), ST88 and t186 (CC88), ST97 and t359 (CC97) and ST121 and t159. We also detect MRSA and MSSA belonging to ST8 with spa t008, genetic characteristics of the major epidemic CAMRSA clone spread in EEUU: USA300. However as many as four different SCCmec (sub) types in five MRSA isolates with spa t008, indicating independent acquisitions in the MSSA ancestor. These results support the hypothesis about the local and continuous emergence of new CA-MRSA clones fromsuccessful MSSA lineages in addition to the dissemination of them is an important process of increasing resistance to betalactam antibiotics. However, only the whole genome sequence of these strains will clarify this hypothesis.