Influence of human wet cerumen on the growth of common and pathogenic bacteria of the ear

The available data on the effect of human wet cerumen on bacterial growth a re not conclusive. Nevertheless it is widely accepted that cerumen has a ba ctericidal effect. In this study the activity of human wet cerumen on bacterial growth was ass essed by applying cerumen suspensions to bacterial cultures. Bacterial coun ts were performed before and after application of cerumen suspensions. A to tal of 383 assays was carried out with 73 pools of cerumen that were tested against cultures of Staphylococcus aureus, Staphylococcus epidermidis, Cor ynebacterium spp., Escherichia coli, Proteus mirabilis, Pseudomonas aerugin osa and Serratia marcescens. An increase in growth occurred much more frequently than a decrease in grow th in almost every microrganism tested, with the mean increase percentage b eing much higher than the mean decrease percentage, except in the case of S . aureus. The largest average growth increase was obtained with E. coli. The largest average decrease in bacterial growth was recorded with S. marcescens. Our study does not support the conception of a decrease in bacterial growth produced by humen wet cerumen. In vitro, the most observable effect was in fact an increase in microbial growth.