In VitroAntibacterial and Antibiofilm Activities of Chlorogenic Acid against Clinical Isolates ofStenotrophomonas maltophiliaincluding the Trimethoprim/Sulfamethoxazole Resistant Strain

Abstract

Thein vitroantibacterial and antibiofilm activity of chlorogenic acid against clinical isolates ofStenotrophomonas maltophiliawas investigated through disk diffusion, minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), time-kill and biofilm assays. A total of 9 clinicalS. maltophiliaisolates including one isolate resistant to trimethoprim/sulfamethoxazole (TMP/SMX) were tested. The inhibition zone sizes for the isolates ranged from 17 to 29 mm, while the MIC and MBC values ranged from 8 to 16 μg mL−1and 16 to 32 μg mL−1. Chlorogenic acid appeared to be strongly bactericidal at 4x MIC, with a 2-log reduction in viable bacteria at 10 h.In vitroantibiofilm testing showed a 4-fold reduction in biofilm viability at 4x MIC compared to 1x MIC values (0.085<0.397A 490 nm) of chlorogenic acid. The data from this study support the notion that the chlorogenic acid has promisingin vitroantibacterial and antibiofilm activities againstS. maltophilia.