Ceftaroline Susceptibility among Isolates of MRSA: A Comparison of EUCAST and CLSI Breakpoints

Methicillin-resistant Staphylococcus aureus (MRSA) is an important bacterial pathogen causing a number of community-acquired and nosocomial infections. Ceftaroline fosamil is a fifth generation cephalosporin, approved for the treatment of infections caused by MRSA. The main objective of this study was to estimate the susceptibility of ceftaroline among isolates of MRSA by using CLSI and EUCAST breakpoints.

Fifty non-duplicate isolates of MRSA were included in the study. Ceftaroline susceptibility was done using E-strip test and interpreted using CLSI and EUCAST breakpoints.

Susceptible isolates were equal (42%) by both CLSI and EUCAST, while resistant isolates were more commonly seen in EUCAST (50%). Ceftaroline MIC ranged from 0.25- >32µg/ml. All the isolates were sensitive to Teicoplanin and Linezolid.

Resistant isolates were less (30%) while using the CLSI 2021 criteria probably due to the inclusion of SDD category. Our study showed that Fourteen isolates (28%) had Ceftaroline MIC >32µg/ml, which is an alarming finding. The high percentage of Ceftaroline resistant isolates in our study probably suggest a hospital spread of Ceftaroline resistant MRSA emphasizing the need for stringent infection control precautions.