Pat DeGagne

Erratum to: EVOTECH®

Correction The original submission of this manuscript included a citation of one of the authors’ patents [1]. During the review process, we were alerted to the existence of another relevant patent. As is the norm, it was our intention that all references to any patents should be removed from the manuscript and replaced by the relevant original peer reviewed research. Unfortunately, the authors were not asked to do this and the manuscript was inadvertently published with the patent citation included. In the interests of fairness, we cite the other patent in question in this Correction [2]. We fully acknowledge that this was an editorial error and apologize to the authors and reviewers for any inconvenience this has caused them.

Improved eradication of Clostridium difficile spores from toilets of hospitalized patients using an accelerated hydrogen peroxide as the cleaning agent

BackgroundC. difficle spores in the environment of patients with C. difficile associated disease (CDAD) are difficult to eliminate. Bleach (5000 ppm) has been advocated as an effective disinfectant for the environmental surfaces of patients with CDAD. Few alternatives to bleach for non-outbreak conditions have been evaluated in controlled healthcare studies.MethodsThis study was a prospective clinical comparison during non-outbreak conditions of the efficacy of an accelerated hydrogen peroxide cleaner (0.5% AHP) to the currently used stabilized hydrogen peroxide cleaner (0.05% SHP at manufacturer recommended use-dilution) with respect to spore removal from toilets in a tertiary care facility. The toilets used by patients who had diarrhea with and without C. difficile associated disease (CDAD) were cultured for C. difficile and were monitored using an ultraviolet mark (UVM) to assess cleaning compliance on a daily basis 5 days per week. A total of 243 patients and 714 samples were analysed. The culture results were included in the analysis only if the UVM audit from the same day confirmed that the toilet had been cleaned.ResultsOur data demonstrated that the efficacy of spore killing is formulation specific and cannot be generalized. The OxivirTB® AHP formulation resulted in statistically significantly (p = 0.0023) lower levels of toxigenic C. difficile spores in toilets of patients with CDAD compared to the SHP formulation that was routinely being used (28% vs 45% culture positive). The background level of toxigenic C. difficile spores was 10% in toilets of patients with diarrhea not due to CDAD. The UVM audit indicated that despite the enhanced twice-daily cleaning protocol for CDAD patients cleaning was not achieved on approximately 30 - 40% of the days tested.ConclusionOur data indicate that the AHP formulation evaluated that has some sporicidal activity was significantly better than the currently used SHP formulation. This AHP formulation provides a one-step process that significantly lowers the C. difficile spore level in toilets during non-outbreak conditions without the workplace safety concerns associated with 5000 ppm bleach.

Comparison of liquid chemical sterilization with peracetic acid and ethylene oxide sterilization for long narrow lumens

The aim of this study was to determine how well peracetic acid liquid chemical sterilization (LCPAS) killed test organisms in the presence of 10% fetal bovine serum and 0.65% salt challenge (RPMI-S) compared with a 100% ethylene oxide (ETO) sterilizer and an ETO hydrochlorofluorocarbon (ETO-HCFC) sterilization method with long (125 cm), narrow (3-mm internal diameter) flexible lumens as the test carrier. The inoculated lumens were dried overnight before processing. The test organisms included Mycobacterium chelonei, Enterococcus faecalis, and Bacillus subtilis. For all 3 organisms tested, the LCPAS process resulted in a 6 log10 reduction in bacterial load compared with a 2.5 log10 to 6 log10 reduction for the 100% ETO and ETO-HCFC sterilizers. Sterilization was achieved for 100%, 61%, and 67% of the lumen test carriers for the LCPAS, 100% ETO, and ETO-HCFC sterilizers, respectively. The data indicate that of the sterilization methods evaluated, LCPAS was the most effective for sterilizing narrow flexible lumens in the presence of residual inorganic and organic soil. This effectiveness was achieved through a combination of organism wash-off and peracetic acid sterilant killing of organisms. Salt was the major compounding factor for effective ETO gas sterilization, because carriers inoculated with organisms in 10% fetal bovine serum alone all were sterilized by both 100% ETO and ETO-HCFC sterilization methods. Our data support the critical need to ensure adequate precleaning of narrow flexible lumen endoscopes before any sterilization method.

Development and validation of rapid use scope test strips to determine the efficacy of manual cleaning for flexible endoscope channels

BACKGROUND Cleaning of flexible endoscopes is most commonly performed using manual methods that are often performed inadequately. The aim of this study was to validate the sample collection protocol and the Rapid Use Scope Test (RUST) and then assess its usefulness in clinical use. METHODS The benchmarks for adequate cleaning were protein <6.4 μg/cm(2), hemoglobin <2.2 μg/cm(2), and carbohydrate <1.2 μg/cm(2). Sample collection consisted of flushing 10 mL of sterile reverse osmosis water through the suction-biopsy port to the distal end. Validation of the RUST audit tool included simulated-use and in-use testing in 43 endoscopy clinics across Canada. RESULTS Simulated-use testing validated that improperly cleaned endoscopes that exceeded the cleaning benchmarks would be flagged by the RUST test. The clinical-use study indicated that 96.6% of 1,489 scope channels tested were RUST negative; however, 19% and 12% of elevator guide-wire channels and endoscopic retrograde colangiopancreatography channels, respectively, exceeded the benchmarks. The survey indicated that reprocessing personnel valued a rapid audit tool for assessing compliance with manual cleaning. CONCLUSION The validated RUST test provides health care users with a rapid audit tool for manual cleaning that can be integrated into the quality program in endoscopy.

Use of an adsorption enzyme immunoassay to evaluate the Haemophilus ducreyi specific and cross-reactive humoral immune response of humans.

Serodiagnosis of chancroid is limited by the cross-reactivity of Haemophilus ducreyi with Haemophilus influenzae and Haemophilus parainfluenzae. This research describes an adsorption enzyme immunoassay (EIA) that assesses the humoral immune response of North Americans and Africans to H. ducreyi. Adsorption effectively removed anti-H. influenzae and anti-H. parainfluenzae antibodies, revealing that North American control sera had no residual anti-H. ducreyi reactivity. However, African control sera still had a residual anti-H. ducreyi response. Assessment of the duration of the humoral immune response in sera from African patients with chancroid showed that the humoral antibodies persisted for up to 8 months after the diagnosis. This may explain the lack of specificity of the adsorption EIA in areas where chancroid is endemic. The detection of the humoral immune response was affected by the strain of H. ducreyi used, with indigent strains being most useful. Using H. ducreyi 35000 for Canadian sera, the sensitivity of the adsorption EIA was 100% and the specificity was 88%. For African sera, H. ducreyi strain R018 was used, and the adsorption EIA had a sensitivity of 81% and a specificity of only 23%. These data reveal that the existing humoral response in a country where chancroid is endemic differs from that in a country where it is not, and that care must be used interpreting unadsorbed humoral immune responses. The adsorption EIA approach may prove useful as an epidemiologic tool for definition of existing (past and present) levels of exposure to H. ducreyi.

EVOTECH® endoscope cleaner and reprocessor (ECR) simulated-use and clinical-use evaluation of cleaning efficacy

BackgroundThe objective of this study was to perform simulated-use testing as well as a clinical study to assess the efficacy of the EVOTECH® Endoscope Cleaner and Reprocessor (ECR) cleaning for flexible colonoscopes, duodenoscopes, gastroscopes and bronchoscopes. The main aim was to determine if the cleaning achieved using the ECR was at least equivalent to that achieved using optimal manual cleaning.MethodsSimulated-use testing consisted of inoculating all scope channels and two surface sites with Artificial Test Soil (ATS) containing 108 cfu/mL of Enterococcus faecalis, Pseudomonas aeruginosa and Candida albicans. Duodenoscopes, colonoscopes, and bronchoscopes (all Olympus endoscopes) were included in the simulated use testing. Each endoscope type was tested in triplicate and all channels and two surface sites were sampled for each scope. The clinical study evaluated patient-used duodenoscopes, bronchoscopes, colonoscopes, and gastroscopes (scopes used for emergency procedures were excluded) that had only a bedside flush prior to being processed in the ECR (i.e. no manual cleaning). There were 10 to 15 endoscopes evaluated post-cleaning and to ensure the entire ECR cycle was effective, 5 endoscopes were evaluated post-cleaning and post-high level disinfection. All channels and two external surface locations were sampled to evaluate the residual organic and microbial load. Effective cleaning of endoscope surfaces and channels was deemed to have been achieved if there was < 6.4 μg/cm2 of residual protein, < 1.8 μg/cm2 of residual hemoglobin and < 4 Log10 viable bacteria/cm2. Published data indicate that routine manual cleaning can achieve these endpoints so the ECR cleaning efficacy must meet or exceed these to establish that the ECR cleaning cycle could replace manual cleaningResultsIn the clinical study 75 patient-used scopes were evaluated post cleaning and 98.8% of surfaces and 99.7% of lumens met or surpassed the cleaning endpoints set for protein, hemoglobin and bioburden residuals. In the simulated-use study 100% of the Olympus colonoscopes, duodenoscopes and bronchoscopes evaluated met or surpassed the cleaning endpoints set for protein, and bioburden residuals (hemoglobin was not evaluated).ConclusionsThe ECR cleaning cycle provides an effective automated approach that ensures surfaces and channels of flexible endoscopes are adequately cleaned after having only a bedside flush but no manual cleaning. It is crucial to note that endoscopes used for emergency procedures or where reprocessing is delayed for more than one hour MUST still be manually cleaned prior to placing them in the ECR.

Evaluation of rapid readout biological indicators for 132°C gravity and 132°C vacuum-assisted steam sterilization cycles using a new automated fluorescent reader

Objective: The primary objective of this study was to evaluate fluorescent readout results of Attest 1291 Biological Indicators (Bis) (3M Health Care, St. Paul, MN) and Attest 1296 BI test packs (containing Attest 1292 Bis) using full and fractional cycles compared with the growth data when prolonged incubation (7 days) was included. Gravity displacement and vacuum-assisted steam sterilization cycles were evaluated. A secondary objective of this study was to evaluate the new automated rapid fluorescent reader (Attest 290 Auto Reader). Design: The rapid readout Bis for gravity displacement and vacuum-assisted steam autoclave cycles at 132° C were processed using full (4 minutes) and four fractional cycles that provided 30% to 80% positive results for growth after 24 hours of incubation (48 hours of incubation for Attest 1292 Bis from the Attest 1296 test packs). Sixty of each type of BI were tested for each cycle (300 of each BI type in total). Results: For all full steam sterilization cycles, results of the rapid fluorescent readout and the 24-hour, 48-hour, and 7-day growth tests were negative for all Attest 1291 and 1292 Bis tested. For all fractional cycles, the 24- and 48-hour growth results for the Attest 1291 and 1292 Bis, respectively, were the same as the 7-day growth results. The fractional cycle data indicated that fluorescent rapid readout was a more sensitive indicator than growth. There were rare (0.9%) false-negative results for Bis under fractional cycle conditions and these all correlated with short fractional cycle exposure times. Conclusions: The fluorescent rapid readout results of the 1291 Bis and 1296 BI test packs reliably predict both 24- and 48-hour and 7-day growth. These data support the value of rapid readout Bis for sterilizer monitoring for both the vacuum-assisted and the gravity displacement steam sterilization cycles. The new automated reader requires less manipulation of the BI and makes monitoring user friendly and less prone to user errors.

Characterization of the Cytopathic Effect of Haemophilus ducreyi

Background and Objectives: Haemophilus ducreyi is the etiologic agent of chancroid, which is a genital ulcer disease that increases the risk of acquiring and transmitting HIV. The pathogenesis of H. ducreyi is not well understood. Goal of this Study The goal of this study was to use a quantitative tetrazolium-based XTT assay to characterize the cytopathic effect of H. ducreyi on human foreskin fibroblasts. Study Design: Haemophilus ducreyi strains 35000, R018, A77 and CIP542 were evaluated using the XTT assay. The role of attachment on resultant CPE was assessed using a wash step 2 hours post-infection. Internalization was evaluated by the gentamicin kill assay. Secreted exotoxin was studied using permeable inserts to separate the bacteria from the HFF monolayer. Results HFF cell damage did not appear to be mediated by a secreted H. ducreyi cytotoxin. Direct contact of viable H. ducreyi with HFF cells was required for cell damage. H. ducreyi strains that attached poorly could be readily removed by a wash step. This reduced their capacity to damage HFF cells significantly. Although some H. ducreyi. strains attach to high levels within 4 hours, no HFF cell damage was detected by the XTT assay. However, once HFF cell damage was detected by 24 hours, it was not easily reversible, despite antibiotic treatment that eradicated H. ducreyi. Internalization of H. ducreyi by HFF cells apparently did not occur to a significant degree. Conclusion This study indicates that classic “soluble exotoxins” are not likely the key component in H. ducreyi pathogenesis. Attachment or direct contact with HFF cells are required for H. ducreyi to cause a CPE.

In vitro activity of lomefloxacin against Chlamydia trachomatis, Neisseria gonorrhoeae, Haemophilus ducreyi, Mycoplasma hominis, and Ureaplasma urealyticum

The in vitro activity of lomefloxacin, a new difluorinated quinolone antimicrobial was compared to comparative agents against organisms causing sexually transmitted diseases. Against Chlamydia trachomatis, Mycoplasma hominis, Ureaplasma urealyticum, Neisseria gonorrhoeae, and Haemophilus ducreyi, lomefloxacin exhibited MIC90 of 2.0, 8.0, 8.0, less than or equal to 0.015, and 0.003 micrograms/ml, respectively. Overall, the lomefloxacin activity was very similar to ciprofloxacin.

Improper positioning of the elevator lever of duodenoscopes may lead to sequestered bacteria that survive disinfection by automated endoscope reprocessors

Graphical Abstract Figure. No Caption available. HighlightsSimulated‐use testing showed that bacteria in the presence of organic material may survive liquid chemical sterilization and HLD after one round of reprocessing if the duodenoscope elevator lever is in the horizontal position.The expected 6 Log10 kill of vegetative Enterococcus faecalis and Escherichia coli may not be achieved when bacteria were sequestered under the horizontal duodenoscope lever in the presence of organic material.There may be a very low margin of safety if bacteria and organic material become sequestered under the duodenoscope elevator lever in the horizontal position. Background: Some outbreaks associated with contaminated duodenoscopes have been attributed to biofilm formation. The objective of this study was to determine whether bacteria within an organic matrix could survive if the elevator lever was improperly positioned in the automated endoscope reprocessor (AER) after 1 round of reprocessing. Methods: Duodenoscope lever cavities with an open or sealed elevator wire channel were inoculated with 6‐7 Log10 of both Escherichia coli and Enterococcus faecalis in ATS2015 (Healthmark Industries, Fraser, MI) and dried for 2 hours. The duodenoscopes with the lever in the horizontal position were processed through 2 makes of AERs. The cavity was sampled using a flush‐brush‐flush method to determine the quantity of surviving bacteria. Results: E faecalis (range, 21‐6 Log10 CFU) and E coli (range, 0‐3 Log10 CFU) survived disinfection of sealed or unsealed elevator wire channel duodenoscopes in 2 different AERs with and without cleaning cycles. Conclusion: If bacteria in organic residue are under the improperly positioned lever, then just 1 round of use is sufficient for bacteria to survive both liquid chemical sterilization and liquid chemical HLD regardless of whether or not the AER had a cleaning cycle.