Biofilms – hidden environmental reservoir of antibiotic resistant microorganisms in ICU — ASN Events
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Biofilms – hidden environmental reservoir of antibiotic resistant microorganisms in ICU (#127)

Jessica L Knight 1 2 , Slade O Jensen 1 2 , Björn A Espedido 1 2 , Kahlid Johani 3 , Karen Vickery 3 , Iain B Gosbell 1 2 4
  1. Molecular Medicine Research Group, School of Medicine, Univeristy of Western Sydney, Campbelltown, NSW
  2. Antibiotic Resistance and Mobile Elements Group, Ingham Institute for Applied Medical Research, Liverpool, NSW
  3. Faculty of Medicine and Health Sciences, Macquarie University, Macquarie Park, NSW
  4. Department of Microbiology and Infectious Diseases, Sydney South West Pathology Services, Liverpool, NSW Health Pathology

Hospital acquired infections (HAIs) are a burden on healthcare systems and patients in terms of lost bed days and additional treatment costs for such infections. Multi faceted infection control protocols are in place to minimise the acquisition of such infections however, the contamination of hospital environmental surfaces has been underestimated as an impacting factor. Previous studies have demonstrated the presence of multi drug resistant biofilms on hospital surfaces. Microbial growth in biofilm structures provides protection against disinfection and also provides a reservoir for microbial release of cells which could result in infection if contact with a contaminated surface occurs.

High touch surfaces were identified using adenosine triphosphate (ATP) bioluminescence readings. The presence of ATP is an indicator of a soiled surface. Surfaces with high ATP bioluminescence readings were destructively sampled from the Intensive Care Unit (ICU) of Liverpool Hospital, NSW and examined for the presence of multi drug resistant microorganisms (MDROs). MDROs such as vancomycin resistant enterococci (VRE) and extended spectrum beta lactamase (ESBL) bacteria were grown from these samples and identified using MALDI-TOF and VITEK for antibiotic sensitivities. VRE environmental isolates were compared to clinical strains collected from ICU patients using ERIC PCR and were found to have similar/identical banding patterns. Samples of surfaces with confirmed MDROs were imaged using scanning electron microscopy and were found to have biofilm growth.

These findings indicate that these multi resistant biofilms are showing resistance to current cleaning protocols and prove difficult to remove via conventional cleaning methods. As the VRE isolates had similar/identical banding patterns to the clinical strains from the ICU, this indicates these biofilms may provide a reservoir of multi resistant bacteria, potentially leading to HAI development. A biofilm targeted cleaning protocol may aid in the removal of these environmental contaminants and may lead to a reduction in HAI acquisition.

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