In previous blogs we discussed how surfaces in close proximity to hospitalized patients become contaminated with a range of pathogens (see here). Our review of contamination of environmental solid surfaces, and soft surfaces demonstrated that these surfaces have a role in the infection process. In this blog I wanted to take the opportunity to outline the evidence that hands or gloves can clearly be contaminated from touching contaminated environmental surfaces.
Ray and colleagues found that hands of healthcare personnel were contaminated with vancomycin-resistant enterococci (VRE) after they touched bed rails and bedside tables in VRE patients’ rooms, without having prior contact with patients (1). Similarly, Bhalla and colleagues also found acquisition of bacterial pathogens on 53% of investigators’ hands after touching environmental surfaces near hospitalized patients, with the commonest bacterial pathogens found being Staphylococcus aureus and VRE (2).
Stiefel and coworkers reported that the frequency of hand contamination with methicillin-resistant Staphylococcus aureus (MRSA) was very similar after contact with commonly examined skin sites and commonly touched environmental surfaces in MRSA carrier patients rooms (40% vs 45%) (3). Similar findings were reported regarding acquisition of VRE, MRSA or Clostridium difficile (CD) spores on gloved hands after contact with commonly touched environmental surfaces such as bed linens, bed rails, and bedside tables as after contact with commonly examined skin sites of VRE, MRSA or CD infected patients, respectively (4-6). A study in Japan revealed that transmission of Streptococcus pyogenes occurred via contact with the contaminated surface of a sheet that covered the bed on which the patients were treated (7).
Patients and contaminated surfaces appear to transfer VRE, MRSA and C. difficile to HCP hands at similar frequencies.
However, in a recent study, compliance with hand hygiene was 80% of 142 opportunities after patient contact compared with only 50% of 196 opportunities after contact with a patient’s environment (p=0.01, Fisher’s exact test) meaning that contamination acquired from a patient’s environment is less likely to be dealt with by hand hygiene.
In vitro studies to assess the transfer from environmental surfaces to healthcare worker hands or gloves has confirmed the rapid dynamic transfer of pathogens from surfaces to hands and vice versa. For example, the transfer efficiency of micro-organisms from fomites to hands and the subsequent transfer from the fingertip to the lip was demonstrated by sampling hands of volunteers after the normal usage of fomites seeded with a pooled culture of a Gram-positive bacterium (Micrococcus luteus), a Gram-negative bacterium (Serratia rubidea) and a phage (PRD-1). The activities were routine daily activities, such as turning on/off a kitchen faucet and holding a phone receiver. Transfer efficiencies were 38.47% to 65.80% and 27.59% to 40.03% for the phone receiver and faucet, respectively. Similar transfer efficiencies were recorded from the contaminated hands to the surfaces, with the number of bacteria transferred to the hands well above the infectious dose (up to 106 cells). Importantly, more than 30% of inoculated bacteria and bacteriophage were transferred from the volunteer’s hands to their lips, with clear implications for the fecal-oral transmission of nosocomial pathogens (8).
Ready transmission was also demonstrated by using another bacteriophage model (phiX174), since its environmental stability is comparable with the most resistant human pathogenic viruses, e.g. polio- or parvoviruses. About 107 pfu were applied to exposed contact points such as door handles or the hands of volunteers. After touching of these handles and common social contacts like hand shaking, re-isolation rates were determined from the hands of the test volunteers. Successive transmission from one person to another could be followed up to the sixth contact person. The bacteriophage could be re-isolated after 24h from the hands of all persons tested even after normal use and cleaning of their hands (9).
Similarly, by using a reverse transcriptase polymerase chain reaction assay it was demonstrated the Norovirus can be readily transferred from contaminated faecal material via fingers and cloths to other hand-contact surfaces, such as taps, door handles and telephone receivers (10).
I hope that we have clearly indicated that inanimate contaminated environmental surfaces can readily contaminate hands and gloves of hospital personnel or others, and thus can serve as a vehicle involved in the indirect transmission of nosocomial pathogens.
In addition inadequate cleaning and disinfection of these surfaces after discharge of an infected or colonized patient, will obviously increase the risk of acquisition of the same pathogen by the subsequent room occupant, and in future blogs we wilrocess as well as what the efficacy of disinfection and cleaning is on microbial reduction and infection prevention.l be reviewing the disinfection and cleaning p
Please feel free to comment or add your thoughts around the evidence for environmental hard and soft surfaces contaminating hands or gloves of healthcare workers.
References quoted in this article
- Ray AJ, Hoyen CK, Taub TF, Eckstein EC, Donskey CJ. Nosocomial transmission of vancomycin-resistant enterococci from surfaces. JAMA 2002;287:1400-1401
- Bhalla A, Pultz NJ, Gries DM et al. Acquisition of nosocomial pathogens on hands after contact with environmental surfaces near hospitalized patients. Infect Control Hosp Epidemiol 2004;25:164-167
- Stiefel U, Cadnum JL, Eckstein BC, Guerrero DM, Tima MA, Donskey CJ. Contamination of hands with methicillin-resistant Staphylococcus aureus after contact with environmental surfaces and after contact with the skin of colonized patients. Infect Control Hosp Epidemiol 2011;32:185-187
- Hayden MK, Blom DW, Lyle EA, Moore CG, Weinstein RA. Risk of hand or glove contamination after contact with patients colonized with vancomycin-resistant enterococcus or the colonized patients’ environment. Infect Control Hosp Epidemiol 2008;29:149-154;
- Boyce JM, Potter-Bynoe G, Chenevert C, King T. Environmental contamination due to methicillin-resistant Staphylococcus aureus: possible infection control implications. Infect Control Hosp Epidemiol 1997;18:622-627;
- Guerrero DM, Nerandzic MM, Jury LA, Jinno S, Chang S, Donskey CJ. Acquisition of spores on gloved hands after contact with the skin of patients with Clostridium difficile infection and with environmental surfaces in their rooms. Am J Infect Control 2012;40:556-558
- Takahashi A, Yomoda S, Tanimoto K, Kanda T, Kobayashi I, Ike Y. Streptococcus pyogenes hospital-acquired infection within a dermatological ward. J Hosp Infect. 1998;40:135-140
- Rusin P, Maxwell S, Gerba C. Comparative surface-to-hand and fingertip-to-mouth transfer efficiency of gram-positive bacteria, gram-negative bacteria, and phage. J Appl Microbiol 2002;93:585-592
- Rheinbaben F, Schunemann S, Gross T, Wolff MH. Transmission of viruses via contact in a household setting: experiments using bacteriophage straight phiX174 as a model virus. J Hosp Infect 2000;46:61-66
- Barker J, Vipond IB, Bloomfield SF. Effects of cleaning and disinfection in reducing the spread of Norovirus contamination via environmental surfaces. J Hosp Infect 2004;58:42-4
Images used in this article.
Handwashing image, VRE image taken from the CDC, PRD-1 SEM image taken from here, Phi X174 taken from here
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