P2-226 Characterization of Bacterial Contamination in Soaps Collected from Commercial Soap Dispensers

Monday, July 27, 2015
Exhibit Hall (Oregon Convention Center)
Jordan Smith
Jennifer Gentry-Shields , North Carolina State University , Raleigh , NC
Lee-Ann Jaykus , North Carolina State University , Raleigh , NC
Introduction:  Hand washing with soap is typically used to prevent the spread of enteric disease and the transfer of harmful pathogens in the environment and to foods. However, recent studies have found that soap dispensers themselves, and hence commercial soap, may become contaminated with bacteria. This contamination can impact the efficiency or utility of hand washing. 

Purpose:  To examine the types and levels of bacteria present in 100 commercial soaps dispensed in containers.

Methods:  One hundred soap samples were collected from restrooms at various businesses, restaurants, schools, and public parks around North Carolina. Data were collected on the type of soap and dispenser (including refillable vs. disposable) and sampling location. Samples were plated for enumeration on Reasoner’s 2A (R2A) and Brain Heart Infusion (BHI) agars in triplicate, and 72 colonies that showed different physical characteristics were then isolated for later sequencing.

Results:  Bacterial contamination was observed in 28/100 (28%) of the soap samples when plated on BHI agar, and 19/100 (19%) on R2A agar. Based on container type, 47% of the soap solutions obtained from refillable soap containers showed bacterial growth, compared to 39% of the soaps obtained from disposable containers. The range on agar plates was 4 CFU/ml to >1200 CFU/ml, with the majority of samples having very low numbers of bacterial colonies, and only ~2% having very high numbers. Sequences for isolate typing are pending.

Significance:  The results suggest that there is a low level of bacterial contamination in public soap dispensers in North Carolina and that the dispenser type makes little difference in the likelihood or levels of bacteria. This contamination may be related to a failure to properly clean the dispenser, and/or associated bacterial growth although studies are merited to better understand the sources and significance of bacterial contamination in commercially dispensed soaps in public restrooms.