A review of the evidence for pathogenic contamination in the nonhospital. implications for infection transmission

Transcription

1 A review of the evidence for pathogenic contamination in the nonhospital environment and implications for infection transmission Elizabeth Scott Simmons College, Boston Simmons Center for Hygiene and Health in Home and Community. & International Forum on Home Hygiene (IFH)

2 The non-hospital environment Growing immuno-compromised population in the community. Emerging pathogens Antibiotic resistance Home-care nursing Grouping of susceptible individuals Declining support for surface cleaning/hygiene practices

3 Microbial ecology vs microbial risk Inanimate surfaces are contaminated! What is the microbial ecology of the indoor environment? Snapshots vs temporal data Sampling techniques: ATP vs lab culture vs molecular Clinical vs non-clinical settings Germs : good germs - bad germs Many representatives of human flora, opportunistic pathogens and some pathogens.

4 Bacterial contamination on planes (McManus & Kelley 2005 J.Appl Micro) Frequently touched surfaces DNA sequencing and BLAST analysis to identify sequences in Genbank. Bacterial diversity highest on lavatory surfaces including door handles, toilet handles and sink faucets. Detected 58 different bacterial genera Most frequently observed species came from 5 genera commonly associated with humans: Streptococcus, Staphylococcus,Cornybacterium, Proprionibacterium and Kocuria. Conclusions: The results show that there is a large diversity of bacterial contamination on aeroplanes, including organisms known to be opportunistic pathogens

5 Surfaces in non-clinical settings Complex & varied situations What is the risk? Setting, e.g. office vs daycare vs home Occupants & activities Type and rate & source of contamination Type of surface What is the likelihood of contact with a surface? >>high touch surfaces

6 Criteria for infection risk associated with surfaces. Reference: Block, 5 th ed. 2001

7 Community based infections linked to high touch surfaces

8 Infectious Gastrointestinal Disease Common but underreported Up to 50% of transmission person-to-person Surface involvement Norovirus, Rotavirus, Campylobacter Foodborne: 48 million cases of foodborne illness/year USA >40% of reported foodborne outbreaks occur at home

9 Skin Infections Common but under- reported Direct and indirect transfer involving surfaces CA-MRSA San Francisco study: 85% of infections occurred outside of healthcare (Liu et al. 2008)

10 Acute respiratory infections Adults: infections/year Children under 5: infections/year Loss of productivity & economic burden Cold viruses, 80% rhinovirus. Influenza epidemics USA: 36,000 deaths, 114,000 hospitalizations. Role of hands and surfaces in transmission of influenza.

11 Hands + high touch surfaces = infection transmission Pets Humans Foods SURFACES Surface=temporary reservoir Pets Humans Foods

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13 Pathogen transfer rates from hand contact surfaces to hands Highly variable Species and strain specific Highest from non-porous surfaces

14 Wet Reservoir Sites E.coli & fecal coliforms Salmonella Shigella sonnei Norovirus Risk is relatively low except during outbreaks of enteric infection

15 Reservoir -disseminator sites E.coli & other coliforms Salmonella Listeria MRSA Fungal contaminants Risk of crosscontamination to other surfaces is constant

16 Hand & Food Contact Surfaces E.coli & coliforms (fecals) Cytomegaolvirus & rotavirus in daycare MRSA: home, athletic & LTCF Vancomycin-resistant enterococci (VRE) in LTCF Rhinovirus & influenza virus in offices. Risk is variable but constant

17 Floors, carpets, athletic mats & soft furnishings C. difficile spores, VRE, Group A streptococci & MRSA in LTCF s MRSA in homes and athletic facilities Enterics (salmonella, rotavirus etc) in daycare Norovirus hotels and cruise ships etc. Risk: for groupings of vulnerables & some specific activities

18 Examples of pathogen transfer between surfaces and hands. Campylobacter & Salmonella in kitchens: hands, cutting boards, rags (Cogan et al 1999 Ltts Appl Micro ) Polio virus following vaccination of infants found on 13% of hand contact surfaces (Curtis et al 2003 IntJ Enviro Hlth) Rhinovirus on 35% hand contact surfaces sampled in hotel rooms (Winther et al 2007 J Med Virology) CA-MRSA average transmission to pigskin from hand contact fomites was 62% of bacteria recovered directly from the fomite (Desai et al 2011 AJIC)

19 SURFACE S.aureus % MRSA % SURFACE S.aureus% MRSA % Sponge/cloth n= Toilet seat 14 0 Dish towel n= Counter top n= Sink 23 3 Door handle n= Drain 20 3 Faucet handle 11 3 Floor n= Toilet floor 11 0 Phone n= Light switch n= Table top 14 0 Flush Handle n= Counter top n= Child training potty n= Fridge handle 11 0 Other Faucet handle 12 6 Child toy 34 0 Microwave touch n= Infant high chair tray n= Garbage bin n= Infant changing mat n= Chopping board n= Pet food dish 15 3 Bathroom TV remote n= Tub 26 3 Phone n= Sink 17 3 Computer Mouse n= Computer Keyboard n= Toilet bowl n=

20 Household Surfaces with MRSA: Evaluating Predictors (Scott et al 2009, AJIC) Surfaces Hand contact vs Non handcontact Wet (W) or Dry (D) surface Dish towel Hand D Kitchen countertop Hand D Kitchen faucet handle Hand D Sponge Hand W Bathroom faucet handle Hand D Bathroom door handle Hand D Infant highchair Hand D Pet food dish Hand D Bathroom sink Hand W Bathroom tub Hand/skin W Kitchen sink Hand W Kitchen drain Non hand W [ Garbage bin Non hand D

21 Current work on MRSA on high touch surfaces in the home Homes of MRSA+ patients Sample other occupants, pets and hand contact surfaces. Molecular analysis using real time PCR (USA 100, 200, 300 & 400) Research questions: If an index patient is colonized, are family members and pets also colonized? Is MRSA found on hand contact surfaces in the home? Are the same strains isolated from household members, pets and surfaces?

22 Conclusions Complex situation in non-hospital environments At risk populations Community-based infections Pathogens survive on, and transmitted to/from surfaces, especially high touch surfaces Implications for where to focus our efforts to interrupt chain of transmission: hands and high touch surfaces.

23 THANK YOU!