Decontamination of Spores on Model Stainless-Steel Surface by Using Foams Based on Alkyl Polyglucosides

In the food industry, the surfaces of processing equipment are considered to be major factors in the risk of food contamination. The cleaning process of solid surfaces is essential, but it requires a significant amount of water and chemicals. Herein, we report the use of foam flows based on alkyl polyglucosides (APGs) to remove spores of Bacillus subtilis on stainless-steel surfaces as the model-contaminated surface. Sodium dodecyl sulfate (SDS) was also studied as an anionic surfactant. Foams were characterized during flows by measuring the foam stability and the bubble size. The efficiency of spores' removal was assessed by enumerations. We showed that foams based on APGs could remove efficiently the spores from the surfaces, but slightly less than foams based on SDS due to an effect of SDS itself on spores removal. The destabilization of the foams at the end of the process and the recovery of surfactant solutions were also evaluated by using filtration. Following a life cycle assessment (LCA) approach, we evaluated the impact of the foam flow on the global environmental footprint of the process. We showed significant environmental impact benefits with a reduction in water and energy consumption for foam cleaning. APGs are a good choice as surfactants as they decrease further the environmental impacts.

Fomite Transmission Follows Invasion Ecology Principles

The invasion ecology principles illustrated in many ecosystems have not yet been explored in the context of fomite transmission. We hypothesized that invaders in fomite transmission are trackable, are neutrally distributed between hands and environmental surfaces, and exhibit a proximity effect. To test this hypothesis, a surrogate invader, Lactobacillus delbrueckii subsp. bulgaricus, was spread by a root carrier in an office housing more than 20 participants undertaking normal activities, and the microbiotas on skin and environmental surfaces were analyzed before and after invasion. First, we found that the invader was trackable. Its identity and emission source could be determined using microbial-interaction networks, and the root carrier could be identified using a rank analysis. Without prior information, L. bulgaricus could be identified as the invader emitted from a source that exclusively contained the invader, and the probable root carrier could be located. In addition to the single-taxon invasion by L. bulgaricus, multiple-taxon invasion was observed, as genera from sputum/saliva exhibited co-occurrence relationships on skin and environmental surfaces. Second, the invader had a below-neutral distribution in a neutral community model, suggesting that hands accrued heavier invader contamination than environmental surfaces. Third, a proximity effect was observed on a surface touch network. Invader contamination on surfaces decreased with increasing geodesic distance from the hands of the carrier, indicating that the carrier’s touching behaviors were the main driver of fomite transmission. Taken together, these results demonstrate the invasion ecology principles in fomite transmission and provide a general basis for the management of ecological fomite transmission.

IMPORTANCE Fomite transmission contributes to the spread of many infectious diseases. However, pathogens in fomite transmission typically are either investigated individually without considering the context of native microbiotas or investigated in a nondiscriminatory way from the dispersal of microbiotas. In this study, we adopted an invasion ecology framework in which we considered pathogens as invaders, the surface environment as an ecosystem, and human behaviors as the driver of microbial dispersal. With this approach, we assessed the ability of quantitative ecological theories to track and forecast pathogen movements in fomite transmission. By uncovering the relationships between the invader and native microbiotas and between human behaviors and invader/microbiota dispersal, we demonstrated that fomite transmission follows idiosyncratic invasion ecology principles. Our findings suggest that attempts to manage fomite transmission for public health purposes should focus on the microbial communities and anthropogenic factors involved, in addition to the pathogens.

Adaptation of the WHO Hand Hygiene Observation Form for Application in Optometry Training Facilities

BACKGROUND

The link between hand and surface hygiene and the spread of disease has been reported by various studies and understanding the appropriate use of hand hygiene is important in healthcare. The World Health Organization (WHO) introduced the "My Five Moments for Hand Hygiene" model to educate healthcare workers about the importance of hand hygiene to stop the spread of disease.

OBJECTIVE

The objectives of this paper were to determine if the WHO Hand Hygiene Observation Form could be used to monitor for hand and personal hygiene practices of Optometry students, and what their actual hygiene practices are in an Optometry training facility in South Africa.

METHODS

This cross-sectional study was performed at an Optometry training facility in South Africa using third (n=32) and fourth year (n=39) students. The Hand Hygiene Knowledge Questionnaire for Health Care Workers by the WHO was used to determine their knowledge regarding hand hygiene. After completing the questionnaire, participants were observed in the clinic while consulting patients to determine the hand and surface hygiene practices they apply.

RESULTS

The WHO hand hygiene observation rubric was not appropriate to evaluate hand and surface hygiene in Optometry facilities. The adapted observation rubric created was a better tool to evaluate student hygiene practices and was able to record which hand or surface hygiene were missed when presented with such opportunities. Although 90.1% of the students knew that germs could be transferred to the patients via hands, only 46.5% routinely used an alcohol-based hand sanitizer.

CONCLUSION

This observation rubric developed during this study can assist in creating awareness with students about their own hand and surface hygiene deficiencies when interacting with patients.

Impacts of Wet Market Modernization Levels and Hygiene Practices on the Microbiome and Microbial Safety of Wooden Cutting Boards in Hong Kong

Accessing food through wet markets is a common global daily occurrence, where fresh meat can be purchased to support an urbanizing world population. Similar to the wet markets in many other metropolitan cities in Asia, Hong Kong wet markets vary and are characterized by differing hygiene routines and access to essential modern technologies. The lack of risk assessments of food contact surfaces in these markets has led to substantial gaps in food safety knowledge and information that could help improve and maintain public health. Microbial profiling analyses were conducted on cutting boards that had been used to process pork, poultry, and seafood at 11 different wet markets. The markets differed in hygiene protocols and access to modern facilities. Irrespective of whether wet markets have access of modern infrastructure, the hygiene practices were largely found to be inefficient based on the prevalence of bacterial species typically associated with foodborne pathogens such as Campylobacter fetus, Clostridium perfringens, Staphylococcus aureus, and Vibrio parahaemolyticus; indicator organisms such as Escherichia coli; as well as nonfoodborne pathogenic bacterial species potentially associated with nosocomial infections, such as Klebsiella pneumoniae and Enterobacter cloacae. Other Vibrio species, V. parahaemolyticus and V. vulnificus, typically associated with contaminated raw or undercooked seafood with the potential to cause illness in humans, were also found on wooden cutting boards. This study indicated that the hygienic practices used in Hong Kong wet markets are not sufficient for preventing the establishment of spoilage or pathogenic organisms. This study serves as a basis to review current hygiene practices in wet markets and provides a framework to reassess existing safety protocols.

A Field Study Into Hong Kong's Wet Markets: Raised Questions Into the Hygienic Maintenance of Meat Contact Surfaces and the Dissemination of Microorganisms Associated With Nosocomial Infections

Millions every day purchase their raw meat in wet markets around the globe, especially in Hong Kong city, where modern and a traditional way of living is made possible. While food hygiene standards in Hong Kong have more recently focused on the safety of meat sold in these wet markets, the hygienic surface level of wooden cutting boards used for processing meats is seldom observed. This original study performed microbial community profiling, as well as isolating and identifying various strains multiple wooden cutting boards from nine wet markets located on Hong Kong Island. Our study also investigated the efficiency of scraping the surface of cutting boards as a traditional cleaning technique in Hong Kong. Results indicate that these hygienic practices are inefficient for guarantying proper surface hygiene as some most tested cutting boards were found to harbor microbial species typically associated with hospital nosocomial infections, such as Klebsiella pneumoniae. Further analysis also led to discovering the presence of antibiotic-resistant genes (ARGs) among isolated strains. Our results showcase the significance and effects of cross-contamination in Hong Kong wet markets, especially with regards to the potential spreading of clinically-relevant strains and ARGs on food processing surfaces. This study should, therefore, serve as a basis to review current hygienic practices in Hong Kong's wet market on a larger scale, thereby improving food safety and ultimately, public health.

Variation in detection limits between bacterial growth phases and precision of an ATP bioluminescence system

To determine the detection limits of the SystemSure Plus, Escherichia coli and Staphylococcus aureus growth curve samples were taken in lag (1 h), log (6 h), stationary (12 h) and death phases (E. coli 144 h, Staph. aureus 72 h). At each time point, the log10 CFU ml(-1) was determined for the dilution where the SystemSure read 0 relative light units (RLU). Average detection limits were E. coli: lag 6·27, log 5·88, stationary 7·45 and death 6·88; Staph. aureus: lag 4·37, log 5·15, stationary 7·88 and death 7·57. Between-run precision was determined with positive control; within-run precision with positive control, lag and log growth for each bacteria. Within-run precision mean RLU (CV): positive control 274 (12%), E. coli lag 1 (63%), log 2173 RLU (19%), Staph. aureus lag 2 (58%) and log 5535 (18%). Between-run precision was 232 (16%). The precision is adequate with most values within the 95% confidence interval. The detection limit varied by 3·51 log10 for Staph. aureus and 1·47 log10 for E. coli. The lowest detection limits were during E. coli log and Staph. aureus lag phases; the highest was during stationary phase. These results suggest that organism identification and growth phase both impact ATP RLU readings.

SIGNIFICANCE AND IMPACT OF THE STUDY

Surface hygiene is a critical component of food safety and infection control; increasingly, ATP detection by bioluminescence is used to evaluate surface hygiene and effective cleaning. This is the first study to show that the number of living and potentially infectious bacteria remaining when the device reads zero varies between the different bacterial life cycle phases: lag, log, stationary and death. ATP device users need to be aware of this information to use the devices appropriately.

How do we assess hospital cleaning? A proposal for microbiological standards for surface hygiene in hospitals

Increasing numbers of hospital-acquired infections have generated much attention over the last decade. The public has linked the so-called 'superbugs' with their experience of dirty hospitals, but the precise role of cleaning in the control of these organisms in unknown. Hence the importance of a clean environment is likely to remain speculative unless it becomes an evidence-based science. This proposal is a call for bacteriological standards with which to assess clinical surface hygiene in hospitals, based on those used by the food industry. The first standard concerns any finding of a specific 'indicator' organism, the presence of which suggests a requirement for increased cleaning. Indicators would include Staphylococcus aureus, including methicillin-resistant S. aureus, Clostridium difficile, vancomycin-resistant enterococci and various Gram-negative bacilli. The second standard concerns a quantitative aerobic colony count of <5 cfu/cm(2) on frequent hand touch surfaces in hospitals. The principle relates to modern risk management systems such as HACCP, and reflects the fact that pathogens of concern are widespread. Further work is required to evaluate and refine these standards and define the infection risk from the hospital environment.