Ceftaroline In-vitro Activity against Methicillin Resistant Staphylococcal Isolates in a Rural Tertiary Healthcare Centre

Abstract

Introduction: The emergence of Methicillin Resistant (MR) staphylococcal infections had led to fewer therapeutic options. Ceftaroline fosamil is the only cephalosporin approved by United States of America (USA) Food and Drug Administration (FDA) till now which has activity against MR staphylococcal isolates. Until now, studies on in-vitro activity of ceftaroline are limited. Aim: To know the susceptibility pattern of Methicillin Resistant Staphylococcus aureus (MRSA) and Methicillin Resistant Coagulase Negative Staphylococci (MRCoNS) against ceftaroline in a rural tertiary health care centre. Materials and Methods: The present cross-sectional study was conducted in a tertiary care hospital in rural part of Karnataka between two months (July and August 2019). A total of 50 consecutive, non repetitive clinical isolates of MRSA and MRCoNS were obtained. Antibiotic susceptibility testing was done according to Clinical and Laboratory Standards Institute (CLSI) guidelines. The Minimum Inhibitory Concentration (MIC) of ceftaroline was detected using E-strips (Biomerieux). The CLSI breakpoints applied for the interpretation of ceftaroline MIC- Sensitive: ≤1 μg/mL; Susceptible Dose Dependent (SDD): 2-4 μg/ mL and resistant ≥8 μg/mL). Staphylococcus aureus American Type Culture Collection (ATCC) 29213 was used as a quality control. Statistical analysis was done using microsoft excel. Percentages were used in this study to analyse variables. Results: Out of 50 MR staphylococcal isolates, 10 (20%) were MRSA and 40 (80%) were MRCoNS. Of the MR staphylococcal isolates tested, 49 (98%) were sensitive to ceftaroline. The MIC 50 and MIC 90 for the 50 MR staphylococci was 0.25 μg/mL and 1 μg/mL, respectively. Conclusion: Ceftaroline demonstrated a potent in-vitro activity against MR staphylococci. So it can be used as an effective drug in the treatment of such infections.