An evaluation, using computerized image analysis, of antimicrobial efficacy of an automatic hand washing machine with ultrasonic wave spraying

Outbreaks where food workers have been implicated in the spread of foodborne disease. Part 10. Alcohol-based antiseptics for hand disinfection and a comparison of their effectiveness with soaps

Alcohol compounds are increasingly used as a substitute for hand washing in health care environments and some public places because these compounds are easy to use and do not require water or hand drying materials. However, the effectiveness of these compounds depends on how much soil (bioburden) is present on the hands. Workers in health care environments and other public places must wash their hands before using antiseptics and/or wearing gloves. However, alcohol-based antiseptics, also called rubs and sanitizers, can be very effective for rapidly destroying some pathogens by the action of the aqueous alcohol solution without the need for water or drying with towels. Alcohol-based compounds seem to be the most effective treatment against gram-negative bacteria on lightly soiled hands, but antimicrobial soaps are as good or better when hands are more heavily contaminated. Instant sanitizers have no residual effect, unlike some antimicrobial soaps that retain antimicrobial activity after the hygienic action has been completed, e.g., after hand washing. Many alcohol-based hand rubs have antimicrobial agents added to them, but each formulation must be evaluated against the target pathogens in the environment of concern before being considered for use. Wipes also are widely used for quick cleanups of hands, other body parts, and surfaces. These wipes often contain alcohol and/or antimicrobial compounds and are used for personal hygiene where water is limited. However, antiseptics and wipes are not panaceas for every situation and are less effective in the presence of more than a light soil load and against most enteric viruses.

COVASIAM: an image analysis method that allows detection of confluent microbial colonies and colonies of various sizes for automated counting

In this work we introduce the confluent and various sizes image analysis method (COVASIAM), an automated colony count technique that uses digital imaging technology for detection and separation of confluent microbial colonies and colonies of various sizes growing on petri dishes. The proposed method takes advantage of the optical properties of the surfaces of most microbial colonies. Colonies in the petri dish are epi-illuminated in order to direct the reflection of concentrated light coming from a halogen lamp towards an image-sensing device. In conjunction, a multilevel threshold algorithm is proposed for colony separation and counting. These procedures improved the quantification of colonies showing confluence or differences in size. We tested COVASIAM with a sample set of microorganisms that form colonies with contrasting physical properties: Saccharomyces cerevisiae, Aspergillus nidulans, Escherichia coli, Azotobacter vinelandii, Pseudomonas aeruginosa, and Rhizobium etli. These physical properties range from smooth to hairy, from bright to opaque, and from high to low convexities. COVASIAM estimated an average of 95.47% (sigma = 8.55%) of the manually counted colonies, while an automated method based on a single-threshold segmentation procedure estimated an average of 76% (sigma = 16.27) of the manually counted colonies. This method can be easily transposed to almost every image-processing analyzer since the procedures to compile it are generically standard.

An evaluation of the residual activity of antiseptic handrub lotions: an 'in use' setting study

An evaluation of the residual activity of quick-drying agents (alcoholic solutions) used for hygienic hand disinfection is described. We looked for residual efficacy following hand disinfection with soap and water alone or followed by one of two alcoholic handrub lotions supplied from an automatic hand washing machine. The bacterial counts on the hands obtained before and within 2 successive hours after disinfection showed that alcoholic chlorhexidine was the most effective for 10 minutes after contamination of the hands. WELPAS (alcoholic chlorbenzarconium) followed this in its immediate effect and was better than soap and water alone. There were no significant differences after 30' or 120' between the three disinfecting methods.

Study of the efficacy of antiseptic handrub lotions with hand washing machines

The effectiveness of quick handwashing in regards to four alcohol-based handrub lotions, including two products already on the market and our original lotions 1, 2, with two different kinds of hand washing machines was studied in vivo. We also tried to evaluate the efficacy of the four lotions in vitro. The in vivo testing of each lotion, including ethanol, was evaluated using two hand washing methods, first with and then without a previous soap wash. Computerized image analysis was used to calculate the bacterial count on the hand surface. The results showed that a 3 second application of the original lotion 2 (0.5% chlorhexidine in a 77% ethyl alcohol solution) preceded by a soap wash eradicated 89.3% of the bacteria on the hands; this was the highest reduction rate of all four detergents. AROKULIN-E (67.9% ethyl alcohol solution) without a prior handwashing produced the lowest reduction, 49.1% against hand surface bacteria. These results were compatible with those in vitro. It seems that an alcohol-based solution containing an effective antimicrobial detergent preceded by a soap wash is necessary to acceptably reduce hand surface bacteria.