Infection control in the home setting and … Are we being too clean? Prof A G Duse, Division of CMID

Importance of domestic setting in transmitting infection:  Across Europe the incidence of IIDs remains unacceptably high – many of these are contracted in the home (? In South Africa)  Many IID & RTIs in the home are mild and self limiting, but represent significant economic and social burden  Demographic & social changes => increasing home care for “at- risk” groups e.g. elderly, I/C patients (recently discharged from hospital, HIV/AIDS), I/S patients. In these groups, infections can be more serious  In 1998, the IFH, produced a set of “Guidelines for prevention and cross-infection in the domestic environment” based on the concept of RISK ASSESSMENT and RISK PREVENTION  An IFH training resource is available in South Africa and will be launched soon

Important areas of focus in the home:  Food – hygiene [purchase, preparation – taking into account potential of cross-contamination], cooking, storage  General hygiene – cleaning versus hygienic cleaning [reducing the number of organisms on a surface to “safe levels”]; remember pets !  Personal hygiene - particularly hand hygiene,  Hygiene in situations where there is more risk

What is good hygiene practice?  Reducing the risks of microbes spreading in the home by:  Understanding their sources: food, people, pets, utensils, toys, surfaces  Identifying where and when there is a risk  Minimizing the risk in an acceptable manner => TARGETED HYGIENE  Hygienic ≠ clean !

Presence of Pathogenic Bacteria in Commercially Available Poultry in South Africa Aithma N, van Nierop W, Duse AG, et al Division of Hospital Epidemiology and Infection Control National Health Laboratory Service and Wits School of Pathology, Johannesburg, South Africa

The Chicken Study….  1.  1.Information on the microbiological quality of raw poultry in South Africa is scant.   2.Aim of the study was to establish the prevalence of food borne pathogens in commercially available carcasses.   3. The study highlights the importance of adequate food preparation and targeted disinfection.

Methods

Methods

Methods

Methods

Total contamination rates Butchery/fresh158(53.3%) Butchery/frozen1710(58.8%) Supermarket/fresh4531(68.9%) Supermarket/frozen167(43.8%) Street vendors63(50.0%) Total9959(59.6%) Source and storage conditionTotalNumber contaminated (number)(percentage)

Extent of contamination according to source and organisms isolated Butchery/fresh156(40.0%)1(6.7%)2(13.3%) Butchery/frozen174(23.5%)4(23.5%)6(35.5%) Supermarket/fresh454(8.9%)22(48.9%)9(20.0%) Supermarket/frozen164(25.0%)2(12.5%)1(6.3%) Street vendors61(16.7%)3(50.0%)1(16.7%) Total9919(19.2%)32(32.3%)19(19.2%) Source andTotal SalmonellaCampylobacterL monocytogenes storage conditionsp no. (%)sp no. (%)no. (%)

Contamination rates of Campylobacter sp according to source and species isolated Butchery/fresh0(0.0%)1(6.7%)0(0.0%) Butchery/frozen2(11.8%)0(0.0%)2(11.8%) Supermarket/fresh5(11.1%)9(20.0%)8(17.8%) Supermarket/frozen1(6.3%)0(0.0%)1(6.3%) Street vendors1(16.7%)2(33.3%)0(0.0%) Total9(9.1%)12(12.1%)11(11.1%) C jejuniC coliC lari # (%)# (%)# (%)

Conclusion  1.  1.A large percentage of chicken carcasses were found to be contaminated with one or more food borne pathogens.   2.This realization should encourage the consumer to practice meticulous food preparation techniques and targeted disinfection practices in the kitchen.

Antimicrobial resistance of bacteria from South African slaughtered and retail chickens   Issues:   Supplemental antibiotics in animal feeds   Staphylococci, Enterobacteriaceae, Salmonella isolates tested for resistance to a variety of antibiotics (tetracycline, streptomycin, gentamicin, oxacillin, vancomycin)   Conclusions: large proportion of bacterial flora on fresh chicken R to wide variety of antibiotics - resultant food-related infections will be more difficult to treat Manie T et al, Letters in Applied Microbiology 1998;26:

A Local [South African] Perspective of Home Hygiene Weber I, Duse A G Division of Hospital Epidemiology and Infection Control National Health Laboratory Service and Wits School of Pathology, Johannesburg, South Africa

Methods  Homes were classified according to the living standards measures (LSM) schemes  A total of 100 homes were included  25 homes from each of the following categories were included:  LSM 1-2  LSM 3-4  LSM 5-6  LSM 7-8

Purpose of home hygiene LSM LSM LSM LSM Did notCleanlinessReduceReduce knoworganismrisk of loaddisease

Source of GIT infection LSM Alcohol Teething LSM Toilets Flies LSM Alcohol Rest-2Hands LSM Crèche Rest-5Med S/E OutsideAtOut/AtFood/AirViralDKOther homehomehomewater

Hand washing LSM Visibly dirty LSM Paint/ chem LSM Paint/ chem LSM After wiping nose BeforeAfterStartAfterAfterFoodAfterAfterOther toilettoileteatingeatingworkprepapetsgarden ration

Purpose of hand washing LSM LSM LSM LSM Reduce visibleReduce micro-Reduce dirt odoursorganismstransmission of infection

Drying of hands LSM LSM LSM LSM YesNo

Drying of hands in kitchen LSM LSM LSM LSM KitchenPaperDishtowelDishclothClothes towel/towel cloth

Are we being too clean?  Hygiene hypothesis states the decreased exposure to microbes has resulted in immune deviation towards an allergic phenotype; hence, increased prevalence of atopic disease  However: no coherent theoretical framework of associations between variables, including independent, moderating & intervening variables  Inter-relationships between infection and immunity, and the role of environmental exposures is unclear  More research needed …

Disinfectants and antibiotic resistance  Can microbial exposure to disinfectants make them resistant to antibiotics?  Theoretically yes: INH and triclosan  Target sites – often different and multiple; correct use at recommended concentration; no in-use evidence of R  Use responsibly & choose products that degrade quickly after use (e.g. bleach, alcohol)  Are antibiotic-resistant bacteria more difficult to kill with disinfectants?  No

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