Oral Presentation Australian Society for Microbiology Annual Scientific Meeting 2017

Biofilms on dry hospital surfaces incorporating multidrug resistant organisms (MRO): is this worldwide? (#80)

Karen Vickery 1 2 , Khalid Aljohani 1 , Dayane Costa 1 3 , Stephanie Dancer 4 , Lillian Lopes 3 , Ananclara Tipple 3 , Anand Deva 1 , Iain Gosbell 5 , Slade Jensen 5 , Gregory Whiteley 6 , Honghua Hu 1
  1. Faculty of Medicine and Health Sciences, Macquarie University, North Ryde, NSW, Australia
  2. ASAM, Macquarie University, Ryde, NSW, Australia
  3. Federal University of Goias, Goiania, Goias, Brazil
  4. NHS Lanarkshire, , Glasgow,, Lanarkshire, United Kingdom
  5. Western Sydney University, Sydney, New South Wales, Australia
  6. Whiteley Corporation, Nth Sydney, New South Wales, Australia

Introduction

Transmission of multidrug resistant bacteria (MRO) within healthcare increases patient morbidity and mortality. Residing in a biofilm makes bacteria more tolerant to desiccation and disinfectant action and may contribute to persistence and transmission of MRO in hospital environments. We determined MRO presence in biofilms contaminating dry surfaces from hospitals around the world.

 

Methods

Following environmental cleaning and disinfection, samples from Brazil (n=40), Australia (n=44), Scotland (n=8) and Saudi Arabia (n=20) were obtained by aseptically cutting fragments from hospital furnishings and equipment. Samples were transported to Australia for biofilm analysis. Bacterial load/cm2 was determined by quantitative PCR of the 16S rRNA gene using eubacterial universal primers. Culturable MRO were detected by sonication in tryptic soya broth followed by culture on HBA plates and specific methicillin resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci (VRE) and extended spectrum beta-lactamase (ESBL) agar plates. Biofilm presence was visually confirmed by live/dead BacLight staining combined with confocal laser scanning microscopy (CLSM) or scanning electron microscopy (SEM).

 

Results

Biofilms were present on 73%, 93%, 100% and 70% of dry hospital surfaces and contained high numbers of bacteria with the mean microbial load/country, as determined by PCR, being 4.4x103, 5.5x105, 2.6x104 and 3.4x104/cm2 for Brazilian, Australian, Scottish and Saudi hospitals respectively. Overall 59% of the 112 samples were still culture positive when they reached Australia for analysis. MRO were isolated from 4/26 (15%), 13/23 (57%), 2/4 (50%) culture positive samples from Brazilian, Australian and Scottish hospitals respectively, MRO were not isolated from Saudi samples. All isolated MRO were from biofilm positive samples. Despite 41% of samples being culture negative, viable bacteria as detected by viability staining, were present in all positive biofilm samples.

 

Conclusion

 

Biofilms containing pathogens, including MRO, commonly contaminate hospital furnishings and equipment worldwide. As bacteria within biofilms are tolerant to disinfection this may be one mechanism through which MRO persist in the environment.