A unique water optional health care personnel handwash provides antimicrobial persistence and residual effects while decreasing the need for additional products

Seal, Lawton A.; Rizer, Ronald L.; Maas-Irslinger, Rainer

BACKGROUND: The Centers for Disease Control and Prevention (CDC) has published guidelines for hand hygiene practices, recommending a handwash regimen that alternates between waterless alcohol products and antimicrobial or nonantimicrobial soap and water. The advent of an alcohol-based product that can be used with or without water (ie, water optional) to decontaminate the hands while providing immediacy of kill and antimicrobial persistence could reduce the confusion associated with handwash guidelines. Such a product has been developed, is alcohol-based (61%), and zinc pyrithione (ZPT) preserved (61% alcohol-ZPT) and has proven to be fully compliant with the Food and Drug Administration (FDA) and CDC guidelines. METHODS: FDA-required testing of the 61% alcohol-ZPT product for the health care personnel handwash indication was performed as outlined in the Tentative Final Monograph (TFM) for Health-Care Antiseptic Drug Products, employing waterless and water-aided product applications. It was next assessed for antimicrobial persistence and residual effects by comparing it, in separate waterless and water-aided applications, with commonly available handwashes containing various antimicrobials in a 5-day study employing 49 subjects, in which samples were collected immediately and at 4 hours and 8 hours postapplication. The skin conditioning properties of this formulation were investigated via appropriate methods. RESULTS: The 61% alcohol-ZPT product easily produced >3.0 log(10) reduction in the indicator strain (Serratia marcescens) following the first wash, exceeding the 2.0 log(10) FDA requirement. This level of performance was maintained through the tenth wash, surpassing the 3.0 log(10) FDA requirement for the handwash indication. For the assessment of persistence and residual effect in the waterless mode, the water-optional, 61% alcohol-ZPT product consistently produced log(10) reductions of nearly 3.5 or greater at every point over the entire study period. In the water-aided configuration, similar results were obtained as log(10) reductions of 2.5 were observed. The formulation is nonirritating, actually contributing to hand skin condition. CONCLUSIONS: The 61% alcohol-ZPT product exceeds all FDA criteria for the health care personnel handwash indication and is a significant advancement in the concept of skin antisepsis. It represents a single product suitable for use in all hand hygiene settings, demonstrating improved antimicrobial persistence and residual effects. The 61% alcohol-ZPT formulation contributes positively to overall hand conditioning, and a previously reported study has documented it to be virucidal for several DNA and RNA viruses.