Efficacy of Germicidal Hand Wash Agents Against Transient Bacteria Inoculated onto Hands

The efficacy of germicidal hand wash agents against transient bacteria ( Escherichia coli and Pseudomonas fluorescens ) in ground beef rubbed onto hands was determined using a hand rinse sampling technique. The reduction in E. coli and P. fluorescens counts on selective growth media and the change in count on Baird-Parker medium were used to indicate action against transient and resident bacteria, respectively. Most of the agents tested, including 4% chlorhexidine gluconate, iodophor (0.75% available iodine), Irgasan DP 300, para-chloro-meta-xylenol (PCMX) as well as the non-germicidal soap, gave marked reduction in counts of E. coli and P. fluorescens (>90% reduction), even after one 15-s wash. The hand dip treatments with iodophor (25 ppm available iodine), hypochlorite (50 ppm available chlorine) or QAC (930 ppm benzalkonium chloride) were generally less effective than hand wash treatments, especially against P. fluorescens . Iodophor (0.75% available iodine) and 4% chlorhexidine gluconate significantly reduced more E. coli on hands than the other agents.