Infection Control & Hospital Epidemiology (2019), 40,60–64 doi:10.1017/ice.2018.285


Original Article


Transmission of Staphylococcus aureus from dry surface biofilm (DSB) via different types of gloves


Shamaila Tahir MBBS, Grad Dip Inf&Immu, PhD1, Durdana Chowdhury MBBS, MPhil1, Mark Legge BAnVetBioSc1, Honghua Hu BSc, Grad DipSc, PhD, MASM1, Greg Whiteley BSc, PhD2, Trevor Glasbey BSc(Chem), PhD2,


Anand K. Deva BSc(Med), MBBS, MS, FRACS1 and Karen Vickery BVSc(Hons), MVSc, PhD, MASM1 1Surgical Infection Research Group, Faculty of Medicine and Health Sciences (FMHS), Macquarie University, Sydney, New South Wales, Australia and 2Whiteley Corporation, Tomago, Newcastle, New South Wales, Australia


Abstract


Background: Pathogens can survive for extended periods when incorporated into biofilm on dry hospital surfaces (ie, dry-surface biofilm, DSB). Bacteria within biofilm are protected from desiccation and have increased tolerance to cleaning agents and disinfectants. Objective: We hypothesized that gloved hands of healthcare personnel (HCP) become contaminated with DSB bacteria and hence may transmit bacteria associated with healthcare-associated infections (HAIs). Method: Staphylococcus aureus DSB was grown in vitro on coupons in a bioreactor over 12 days with periodic nutrition interspersed with long periods of dehydration. Each coupon had ~107 DSB bacterial cells. Transmission was tested with nitrile, latex, and surgical gloves by gripping DSB-covered coupons then pressing finger tips onto a sterile horse blood agar surface for up to 19 consecutive touches and counting the number of colony-forming units (CFU) transferred. Coupons were immersed in 5% neutral detergent to simulate cleaning, and the experiment was repeated. Results: Bacterial cells were readily transmitted by all 3 types of gloves commonly used by HCP. Surprisingly, sufficient S. aureus to cause infection were transferred from 1 DSB touch up to 19 consecutive touches. Also, 6 times more bacteria were transferred by nitrile and surgical gloves than to latex gloves (P <.001). Treating the DSB with 5% neutral detergent increased the transmission rate of DSB bacteria 10-fold.


Conclusion: Staphylococcus aureus incorporated into environmental DSB and covered by extracellular polymeric substances readily contaminates gloved hands and can be transferred to another surface. These results confirm the possibility that DSB contributes to HAI acquisition.


(Received 13 June 2018; accepted 9 October 2018; electronically published 13 November 2018)


Healthcare-associated infections (HAIs) are a worldwide health issue that result in huge costs to the health system.1,2 TheWorld Health Organization (WHO) states that 7% of hospitalized patients in developed countries and 10% of hospitalized patients in developing countries will acquire an HAI.3 In November 2016, the WHO released guidelines for prevention of HAI worldwide, emphasizing control strategies to prevent pathogen transmission.4 Dancer et al4 emphasized the role of environmental cleaning in controlling HAI. However, hospital cleaning alone5 fails to pre- vent the transfer of pathogens.6,7 Pathogens shed from infected patients can survive up to 7 months8 on dry hospital surfaces, whereas bacteria incorporated into dry surface biofilm (DSB) (ie, bacteria surrounded by extracellular polymeric substances [EPS]) can survive more than 12 months.9 Environmental contamination


Author for correspondence: Shamaila Tahir, Level 1, 75 Talavera Road, Macquarie University, NSW, Australia. E-mail: shamaila.tahir@mq.edu.au


Cite this article: Tahir S, et al. (2019). Transmission of Staphylococcus aureus from


dry surface biofilm (DSB) via different types of gloves. Infection Control & Hospital Epidemiology 2019, 40, 60–64. doi: 10.1017/ice.2018.285


© 2018 by The Society for Healthcare Epidemiology of America. All rights reserved.


the contaminated hands of healthcare personnel (HCP).13 Con- sequently, hand hygiene is accepted as the most significant intervention in the preventing HAI.14 Compliance with hand hygiene is often poor, especially when it comes to hand hygiene following touching items such as bed rails and chairs in the patient surroundings.15 Recently, our group successfully demon- strated high transmission rates of DSB bacteria via bare hands before and after wetting with 5% neutral detergent.16 Infection control guidelines recommend the use of gloves as a practical means of preventing transmission of infective pathogens and decreasing transient contamination of HCP hands.17,18


is thought to be responsible for new occupants in rooms pre- viously occupied by patients suffering from vancomycin-resistant Enterococcus (VRE), methicillin-resistant Staphylococcus aureus (MRSA), or Clostridium difficile being at higher risk of acquiring these pathogens.10,12 The presence of biofilms on 93% of ICU furnishings suggests that biofilms formed on dry surfaces escape current cleaning and disinfection protocols and may contribute to nosocomial infection by providing a niche for bacterial persis- tence and release of free-floating bacteria into the environment.9 The most important route of transmission of HAI pathogens is


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