Ceftaroline Activity Against S. aureus Clinical Isolates from Argentina: Association with Different MRSA Clonal Types.

CORSO A.; GAGETTI P.; CERIANA P.; LUCERO C.; EGEA A.L.; BARCUDI D.; GRUPO S. AUREUS ARGENTINA; BOCCO J.L.; SOLA C.

Boston

Congreso; ASM Microbe 2016; 2016

American Society for Microbiology

MRSA is an increasing problem worldwide, both in hospitals (healthcare-associated-HA) and in the community (community-associated-CA). In a previous study, we demonstrated that higher rates of MRSA were mainly associated with the spread of two CA-MRSA clones ST5-IV (32%) and ST30-IV (32%) and one HA-associated ST5-I Cordobes/Chilean (19%) (Egea et al. Int J Med Microbiol 2014; 304:1086-99). The aim of the present study was to evaluate in the same collection. ceftaroline (CPT) susceptibility and its association with the di愀erent MRSA clonal types Methods: 591 consecutive S. aureus clinical isolates were collected in 66 hospitals from 20 provinces and BA City in Argentina, 322 were MRSA (54.5%). Susceptibility to CPT was performed by agar dilution and interpreted according to CLSI M100-S25. The 322 MRSA isolates (231 CA and 91 HA) were previously studied by SCCmec, spa-typing, PVL, PFGE and MLST by standard procedures Results: The prevalence of intermediate (I) resistance to CPT (MIC 2mg/L) was 6.4% (38/591) for S. aureus, MIC 0.25/1 mg/L, range 0.06-2 mg/L. All MSSA isolates were susceptible to CPT with MIC 0.25 mg/L, range 0.06-0.25 mg/L. Among MRSA, 11.8% (38/322) were CPT-I. CPT resistant isolates were not detected (MIC>4 mg/L). The susceptibility pro⠀les of CA and HA-MRSA clones are shown in Table(1).Conclusions: CA-MRSA isolates were CPT susceptible independently of the clone involved. In contrast, in HA-MRSA isolates, CPT susceptibility was strongly associated to the clonal type, being ST5-I Cordobes/Chilean the main clone associated with CPT-I isolates.(1) See Table: http://http://files.abstractsonline.com/CTRL/c5/8/f3b/163/4f3/49d/5ae/8d8/88c/d07/82a/c8/g5139_1.jpg