Evaluation of novel disinfection methods for the remediation of heavily contaminated TMVs and water systems with Pseudomonas aeruginosa biofilm: considerations for new and existing healthcare water systems.

BACKGROUND: Pseudomonas aeruginosa is a leading cause of nosocomial Gram-negative bacteraemia. Water systems are a well-documented source of P. aeruginosa and established biofilms are difficult to remove. AIM: To evaluate the efficacy of regular flushing, peracetic acid disinfection, in-tap thermal disinfection and in-line thermal disinfection to eradicate P. aeruginosa biofilm in a colonised tap model. METHODS: A simulated tap system was constructed and inoculated with a reference and an environmental strain of P. aeruginosa to form biofilm. Water samples were collected from the taps and P. aeruginosa levels enumerated following disinfection methods. To simulate regular flushing, taps were flushed for 5 minutes, 5 times per day with water tested daily. Peracetic acid (4000 PPM) was manually injected into the system and flushed through the system with a pump. Thermal flushing at 60°C was performed in-line and with an in-tap bypass valve. Tests were conducted with cross-linked polyethylene (PEX) piping and repeated with copper piping. FINDINGS: Regular flushing and peracetic acid applied with a pump did not reduce P. aeruginosa levels. A limited reduction was observed when manually injecting peracetic acid. In-tap thermal flushing eradicated P. aeruginosa in copper piping but not PEX. In-line thermal flushing was the most effective at reducing P. aeruginosa levels; however, did not eradicate the biofilm. CONCLUSION: In-line thermal flushing was the most effective method to remove P. aeruginosa biofilm. Results vary significantly with the strain of bacteria and the composition of the plumbing. Several methods used in combination may be necessary to remove established biofilm.

Thrombin detection using a piezoelectric aptamer-linked immunosorbent assay.

The development of diagnostic assays using highly targeted specific aptamers with existing detection platforms has been an endeavor with few opportunities until now. Many current commercially available diagnostic platforms make use of detection systems employing capture agents composed of modified antigen-specific antibodies coupled with a variety of detection modalities, including radioimmunoassays, fluorescence-based detection assays, electro/chemiluminescence assays, and immunoradiometric assays. In the studies presented here, a novel frequency-modulating technology from BioScale called Acoustic Membrane MicroParticle (AMMP) detection was used to demonstrate a sensitive and reproducible method of incorporating aptamers as capture and detection agents. The method provides a robust and rapid detection of thrombin in human serum while also eliminating the labor-intensive efforts of Western blot analysis and is not affected by the interfering substances found in serum that often affect optical-based detection systems. In addition, we have demonstrated, for the first time, the adaptation of the AMMP platform to exploit aptamers against a clinically relevant target. The AMMP platform is an ideal medium for using aptamers in commercial assay development for application in a clinical setting.

Assessment of a rapid diagnostic test to exclude bacteraemia and effect on clinical decision-making for antimicrobial therapy.

Unnecessary antimicrobial treatment promotes the emergence of resistance. Early confirmation that a blood culture is negative could shorten antibiotic courses. The Cognitor Minus test, performed on blood culture samples after 12 hours incubation has a negative predictive value (NPV) of 99.5%. The aim of this study was to determine if earlier confirmation of negative blood culture result would shorten antibiotic treatment. Paired blood cultures were taken in the Critical Care Unit at a teaching hospital. The Cognitor Minus test was performed on one set >12 hours incubation but results kept blind. Clinicians were asked after 24 and 48 hours whether a result excluding bacteraemia or fungaemia would affect decisions to continue or stop antimicrobial treatment. Over 6 months, 125 patients were enrolled. The median time from start of incubation to Cognitor Minus test was 27.1 hours. When compared to 5 day blood culture results from both the control and test samples, Cognitor Minus gave NPVs of 99% and 100% respectively. Test results would have reduced antibiotic treatment in 14% (17/119) of patients at 24 and 48 hours (24% at either time) compared with routine blood culture. The availability of rapid tests to exclude bacteraemia may be of benefit in antimicrobial stewardship.

Identification of Clostridium difficile Reservoirs in The Patient Environment and Efficacy of Aerial Hydrogen Peroxide Decontamination.

OBJECTIVE To identify, using a novel enhanced method of recovery, environmental sites where spores of Clostridium difficile persist despite cleaning and hydrogen peroxide aerial decontamination. DESIGN Cohort study. SETTING Tertiary referral center teaching hospital. METHODS In total, 16 sites representing high-frequency contact or difficult-to-clean surfaces in a single-isolation room or bed area in patient bed bays were sampled before and after terminal or hydrogen peroxide disinfection using a sponge swab. In some rooms, individual sites were not present (eg, there were no en-suite rooms in the ICU). Swab contents were homogenized, concentrated by membrane-filtration, and plated onto selective media. Results of C. difficile sampling were used to focus cleaning. RESULTS Over 1 year, 2,529 sites from 146 rooms and 44 bays were sampled. Clostridium difficile was found on 131 of 572 surfaces (22.9%) before terminal cleaning, on 105 of 959 surfaces (10.6%) after terminal cleaning, and on 43 of 967 surfaces (4.4%) after hydrogen peroxide disinfection. Clostridium difficile persisted most frequently on floor corners (97 of 334; 29.0%) after disinfection. Between the first and third quarters, we observed a significant decrease in the number of positive sites (25 of 390 vs 6 of 256). However, no similar change in the number of isolates before terminal cleaning was observed. CONCLUSION Persistence of C. difficile in the clinical environment was widespread. Although feedback of results did not improve the efficacy of manual disinfection, numbers of C. difficile following hydrogen peroxide gradually declined. Infect Control Hosp Epidemiol 2017;38:1487-1492.

Can botulinum toxin decrease carer burden in long term care residents with upper limb spasticity? A randomized controlled study.

OBJECTIVE: To evaluate whether botulinum toxin can decrease the burden for caregivers of long term care patients with severe upper limb spasticity. METHOD: This was a double-blind placebo-controlled trial with a 24-week follow-up period. SETTING: A 250-bed long term care hospital, the infirmary units of 3 regional hospitals, and 5 care and attention homes. PARTICIPANTS: Participants included 55 long term care patients with significant upper limb spasticity and difficulty in basic upper limb care. INTERVENTIONS: Patients were randomized into 2 groups that received either intramuscular botulinum toxin A or saline. MAIN OUTCOME MEASURES: The primary outcome measure was provided by the carer burden scale. Secondary outcomes included goal attainment scale, measure of spasticity by modified Ashworth score, passive range of movement for shoulder abduction, and elbow extension and finger extension. Pain was assessed using the Pain Assessment in Advanced Dementia Scale. RESULTS: A total of 55 patients (21 men; mean age = 69, SD =18) were recruited. At week 6 post-injection, 18 (60%) of 30 patients in the treatment group versus 2 (8%) of 25 patients in the control group had a significant 4-point reduction of carer burden scale (P < .001). There was also significant improvement in the goal attainment scale, as well as the modified Ashworth score, resting angle, and passive range of movement of the 3 regions (shoulder, elbow, and fingers) in the treatment group which persisted until week 24. There were also fewer spontaneous bone fractures after botulinum toxin injection, although this did not reach statistical significance. No significant difference in Pain Assessment in Advanced Dementia scale was found between the 2 groups. No serious botulinum toxin type A-related adverse effects were reported. CONCLUSION: Long term care patients who were treated for upper limb spasticity with intramuscular injections of botulinum toxin A had a significant decrease in the caregiver burden. The treatment was also associated with improved scores on patient-centered outcome measures.