Daptomycin MICs by Broth Microdilution Method Against Staphylococcus aureus in Clinical Specimens: A Cross-Sectional...

To explore the distribution of daptomycin (DAP) minimum inhibitory concentrations (MICs) in Staphylococcus aureus isolated from complicated skin, soft tissue, and bloodstream infections collected from the Pakistani population using broth microdilution (BMD).

Descriptive, cross-sectional study. Place and Duration of the Study: Department of Pathology and Laboratory Medicine, The Aga Khan University Hospital, from May to October 2021.

Through consecutive sampling techniques, 169 Staphylococcus aureus (S. aureus) isolated from clinical specimens including pus, tissue, and blood were collected. Patients' data including age, gender, geographical location, specimen site, and methicillin susceptibility were collected from the laboratory data. BMD was used to determine MICs of clinical isolates and S. aureus ATCC 29213. DAP MIC ≤1.0 µg/ml was considered susceptible according to the Clinical and Laboratory Standards Institute M100.

Among all the clinical isolates, 144 (85%) and 25 (15%) were from skin and soft tissue and blood, respectively. All isolates were susceptible to DAP with MIC50, MIC90, and MIC range of 0.25 µg/ml, 0.5 µg/ml, and 0.06 - 0.5 µg/ml, respectively.

These study findings demonstrated low in-vitro MICs for DAP against S. aureus in tested isolates from a diverse variety of patient specimens from across Pakistan.

Daptomycin, Staphylococcus aureus, Broth microdilution, Minimum inhibitory concentrations.