In Vitro Activity of Ceftaroline against methicillin resistant Staphylococcus aureus (MRSA) isolates from different clinical samples: A study from a tertiary care hospital.

Abstract

Background: Ceftaroline is a novel, fifth generation cephalosporin, with potent activity against methicillin-resistant Staphylococcus aureus (MRSA) strains. Our study is aimed to assess the spectrum and potency of Ceftaroline against MRSA isolates from different clinical samples.

Methods: A total of 126 methicillin resistant Staphylococcus aureus (MRSA) strains isolated from different clinical samples from patients hospitalized in 2020 due to documented skin and soft tissue infection, intra-abdominal infection, lower respiratory tract infection, and blood stream infections were tested for susceptibility to Ceftaroline. Methicillin resistance was detected by Kirby-Bauer method using 30‑µg cefoxitin disc. Ceftaroline minimum inhibitory concentrations (MIC) was detected for all the 126 isolates by using the E strips of Ceftaroline (biomerieux).

Results: During our study, of the 126 MRSA isolates tested, all were seen sensitive to Ceftaroline. The MIC values ranged from 0.25 to 4 µg/ml. Only six isolates showed the maximum MIC of 4µg/ml (Blood samples), which is in the intermediate susceptible range. The MIC₅₀ and the MIC₉₀ of the MRSA isolates were 0.5 µg/ml and 2µg/ml, respectively. The percentage of susceptible MRSA strains were 95.2%, while 4.8% were susceptible dose dependent (SDD). None of the MRSA isolates showed resistance to Ceftaroline.

Conclusion: This study reveals the patterns of ceftaroline susceptibility of MRSA isolates from various clinical samples from a previously unreported geographical location. Overall, ceftaroline showed excellent in vitro activity against MRSA isolates and should be considered as an efficient alternative for the treatment of MRSA infections.