Abstract
Background
The parenteral cephem ceftaroline (CPT) fosamil is approved for the treatment of patients with skin and skin structure infections (SSSIs) caused by Staphylococcus aureus (both methicillin-susceptible [MSSA] and methicillin-resistant [MRSA] isolates), β-hemolytic streptococci (Streptococcus pyogenes, Streptococcus agalactiae), and select species of Enterobacteriaceae (Escherichia coli, Klebsiella pneumoniae, Klebsiella oxytoca). Limited data have been published on the in vitro activity of CPT against recent clinical isolates cultured from patients with SSSIs in Latin America (LA).
Methods
Standard CLSI broth microdilution MIC determinations (M07) were performed with CPT and comparator agents. MICs were interpreted using current CLSI M100 MIC breakpoints. Clinically relevant, non-duplicate, isolates cultured from patients with SSSIs in 6 countries in LA in 2017 were tested by the AWARE Surveillance Program central laboratory (IHMA). In total, 1,435 non-duplicate isolates of MSSA, MRSA, β-hemolytic streptococci, and Enterobacteriaceae were tested: Argentina (n = 349/24.3% of all isolates tested), Brazil (114/7.9%), Chile (153/10.7%), Columbia (175/12.2%), Mexico (339/23.6%), and Venezuela (305/21.3%).
Results
CPT activity is summarized in the following table.
| CPT MIC Breakpoints (µg/mL) | CPT MIC (µg/mL) | CPT MIC Interpretation | |||||
|---|---|---|---|---|---|---|---|
| Bacteria | n | S | I | R | MIC50 | MIC90 | % S | % I | % R |
| MSSA | 354 | ≤1 | 2 | ≥4 | 0.25 | 0.5 | 100 | 0 | 0 |
| MRSA | 389 | ≤1 | 2 | ≥4 | 0.5 | 1 | 95.1 | 4.9 | 0 |
| β-Hemolytic streptococcia | 130 | ≤0.5 | − | − | 0.008 | 0.015 | 100 | − | − |
| Enterobacteriaceae, All | 562 | ≤0.5 | 1 | ≥2 | 0.5 | >128 | 55.3 | 3.9 | 40.8 |
| Enterobacteriaceae, ESBL screen-negative | 358 | ≤0.5 | 1 | ≥2 | 0.12 | 1 | 86.6 | 5.9 | 7.5 |
a S. pyogenes (n = 90), S. agalactiae (n = 26), and S. dysgalactiae (n = 14).
Conclusion
Overall, 100% of MSSA and 95.1% of MRSA from LA were susceptible to CPT (MIC ≤1 µg/mL); 19 isolates of MRSA were CPT-intermediate (MIC 2 µg/mL) with 17 of the 19 isolates being from Chile; no CPT-resistant MRSA were observed. All β-hemolytic streptococci and 86.6% of ESBL-negative Enterobacteriaceae were also susceptible to CPT. CPT continues to demonstrate potent in vitro activity against clinically relevant pathogens associated with SSSIs for patients in LA.
Disclosures
M. Hackel, Pfizer Inc.: Consultant, Consulting fee. IHMA, Inc.: Employee, Salary. J. Karlowsky, IHMA, Inc.: Consultant, Consulting fee. D. Sahm, Pfizer Inc.: Consultant, Consulting fee. IHMA, Inc.: Employee, Salary. G. G. Stone, Pfizer Inc.: Employee, Salary. AstraZeneca: Former Employee and Shareholder, Salary.
Session: 249. Skin and Skin Structure Infection
Saturday, October 6, 2018: 12:30 PM