Effect of promethazine against <i>Staphylococcus aureus</i> and its preventive action in the formation of biofilms on silicone catheters

Urinary infections caused by <i>Staphylococcus aureus</i> are commonly associated with urinary catheterization and often result in severe complications. Given this problem, the objective of the study was to investigate the preventive action of promethazine (PMT) against the formation of methicillin-resistant <i>Staphylococcus aureus</i> (MRSA) biofilms when impregnated in urinary catheters. For this purpose, techniques such as broth microdilution, checkerboard, impregnation on urinary catheter fragments, flow cytometry assays and scanning electron microscopy were employed. PMT exhibited antimicrobial activity with Minimum Inhibitory Concentration (MIC) values ranging from 171 to 256 µg/mL, predominantly additive interaction in combination with oxacillin (OXA) and vancomycin (VAN), and a reduction in cell viability of biofilms formed and forming by methicillin-sensitive and -resistant <i>S. aureus</i>. Morphological alterations, damage to the membrane, and genetic material of cells treated with promethazine were also observed. The results demonstrated that PMT can be classified as a promising antimicrobial agent for use in the antibacterial coating of long-term urinary devices.