Dayane de Melo Costa

Characterization of microbial community composition, antimicrobial resistance and biofilm on intensive care surfaces

BACKGROUND Organisms causing healthcare associated infections can be sourced from the inanimate environment around patients. Residing in a biofilm increases the chances of these organisms persisting in the environment. We aimed to characterise bacterial environmental contamination, genetically and physiologically, and relate this to general intensive care unit (ICU) cleanliness. METHODS Cleanliness was determined by adenosine triphosphate (ATP) measurements of 95 high-touch objects. Bacteriological samples were obtained from the same sites (n=95) and from aseptically removed sections (destructive samples, n=20). Bacterial enrichment culture was conducted using tryptone soya broth prior to plating on horse blood agar, MacConkey agar, and screening chromogenic agar for identification of multidrug resistance organism (MDRO). Bacterial load and microbial diversity were determined using quantitative PCR (qPCR) and next generation DNA sequencing respectively. Confocal laser scanning microscopy and scanning electron microscopy were used to visually confirm the biofilm presence. RESULTS Many intensive care surfaces (61%) were highly contaminated by biological soil as determined by ATP bioluminescence testing. The degree of biological soiling was not associated with bacterial contamination as detected by qPCR. Bacterial load ranged from 78.21 to 3.71×108 (median=900) bacteria/100cm2. Surface swabs from 71/95 sites (75%) were culture-positive; of these 16 (22.5%) contained MDRO. The most abundant genera were Staphylococcus, Propionibacterium, Pseudomonas, Bacillus, Enterococcus, Streptococcus and Acinetobacter. Biofilm was visually confirmed by microscopy on 70% (14/20) of items. CONCLUSION Bacterial biofilms and MDROs were found on ICU surfaces despite regular cleaning in Saudi Arabia, suggesting that biofilm development is not controlled by current cleaning practices.

Alcohol fixation of bacteria to surgical instruments increases cleaning difficulty and may contribute to sterilization inefficacy

HighlightsExtended water soak or drying times increased the attachment of soil to instruments.Alcohol exposure increased the attachment of soil to instruments.Bacterial load was reduced by soaking/spraying, but not by wiping with alcohol.Alcohol exposure and extended soak or drying times before cleaning increases cleaning difficulty and should be discouraged. Background Alcohol is frequently inappropriately used on surgical instruments to reduce bacterial contamination, but fixes protein to stainless steel. Here we compare the effect of air drying, prolonged soaking in water, and alcohol treatment on cleaning difficulty of contaminated forceps. Methods Haltsted‐mosquito forceps were contaminated with only Staphylococcus aureus. Instruments were air‐dried for 10 (control), 75, or 240 minutes, soaked in water, or air dried then treated with ethanol or isopropanol for 10 seconds. All instruments were prewashed for 15 minutes. Forceps contaminated with blood and S aureus or Pseudomonas aeruginosa were dried and then sprayed or wiped with ethanol, and prewashed. Bacterial viability and soiling were determined by standard plate culture and crystal violet staining, respectively. Results Soaking or spraying instruments with alcohol significantly reduced viable bacterial numbers, but significantly increased soil attached to forceps, as did air drying. Wiping instruments with alcohol had little effect on bacterial viability, but increased cleaning difficulty. Soaking in water for 75 or 240 minutes increased cleaning difficulty perhaps due to bacterial attachment to forceps. Conclusions Treating contaminated instruments with alcohol, allowing them to dry, or allowing them to soak in water for prolonged periods increases cleaning difficulty and should be discouraged.

Reprocessing safety issues associated with complex-design orthopaedic loaned surgical instruments and implants

BACKGROUND The acquisition of reusable surgical instruments (RSIs) through loaner system is a worldwide phenomenon, particularly in orthopaedic surgeries. Loaner sets contain high-complex design RSIs, which are very difficult to clean, and also include single use implants, such as screws, that remain in the surgical tray and are subjected to multiple reprocessing until they are implanted. Inadequate cleaning of SI and various exposures of single-use implants to physical, chemical and biological agents can compromise their quality/safety and promote biofilm formation. The difficulty in cleaning is compounded in middle and low-income countries where automated cleaning infrastructure at sterilizing service units is often unavailable, and thus manual cleaning only is performed. Thus, we aimed to determine the condition of orthopaedic loaned sets when delivered to the hospital, assess the quality of complex-design RSIs reprocessed by manual cleaning, and evaluate the effect of multiple reprocessing on single-use implant (screw). METHODS Flexible medullary reamers (FMRs), depth gauges and screws used for femur intramedullary nailing, in clinical use for >1 year, were obtained from three Brazilian loaner companies and assessed for residual ATP, protein, bacterial contamination, endotoxin and/or biofilm at delivery at the hospital, following cleaning and steam sterilisation. RESULTS Before cleaning, blood was visible on a RSIs tray, and RSIs/screws were contaminated with high amounts of ATP, protein and bacteria. Visible soil was released during brushing of a FMR lumen and, following cleaning, the inner layer of 34/40 were visible soiled, and over 5/8 were protein test positive. Following sterilisation, biofilm and soil, including fragments appearing to be bone, were detected by scanning electron microscopy on RSIs/screws. A sterilised FMR revealed visible soil on the inner layer. Endotoxin tests were negative. CONCLUSION The contaminated condition of loaned-complex-designed RSIs/screws upon arrival at the hospital and after reprocessing points to the insufficiency of manual reprocessing and management practices related to this instruments/implants. A multidisciplinary approach involving expert in design/manufacture, regulating, managing, reprocessing and surgeons is suggested to improve RSIs manufacture that enables complete decontamination and maintain the surgical patient safety.

Patient shoe covers: Transferring bacteria from the floor onto surgical bedsheets

Forty disposable medical shoe covers were briefly exposed to the surgical floor and were found contaminated by a large number of bacteria. This study also demonstrated live bacteria, including pathogens attached to contaminated shoe covers, can be subsequently transferred to surgical bedsheets. We suggest an infection control policy should be considered to prevent patients returning to their bed with contaminated disposable shoe covers.