To evaluate common hand hygiene methods for efficacy in removing Clostridium difficile.
Randomized crossover comparison among 10 volunteers with hands experimentally contaminated by nontoxigenic C. ...difficile.
Interventions included warm water with plain soap, cold water with plain soap, warm water with antibacterial soap, antiseptic hand wipes, alcohol-based handrub, and a control involving no intervention. All interventions were evaluated for mean reduction in colony-forming units (CFUs) under 2 contamination protocols: "whole hand" and "palmar surface." Results were analyzed according to a Bayesian approach, by using hierarchical models adjusted for multiple observations.
Under the whole-hand protocol, the greatest adjusted mean reductions were achieved by warm water with plain soap (2.14 log(10) CFU/mL 95% credible interval (CrI), 1.74-2.54 log(10) CFU/mL), cold water with plain soap (1.88 log(10) CFU/mL 95% CrI, 1.48-2.28 log(10) CFU/mL), and warm water with antibacterial soap (1.51 log(10) CFU/mL 95% CrI, 1.12-1.91 log(10) CFU/mL), followed by antiseptic hand wipes (0.57 log(10) CFU/mL 95% CrI, 0.17-0.96 log(10) CFU/mL). Alcohol-based handrub (0.06 log(10) CFU/mL 95% CrI, -0.34 to 0.45 log(10) CFU/mL) was equivalent to no intervention. Under the palmar surface protocol, warm water with plain soap, cold water with plain soap, and warm water with antibacterial soap again yielded the greatest mean reductions, followed by antiseptic hand wipes (26.6, 26.6, 26.6, and 21.9 CFUs per plate, respectively), when compared with alcohol-based handrub. Hypothenar (odds ratio, 10.98 95% CrI, 1.96-37.65) and thenar (odds ratio, 6.99 95% CrI, 1.25-23.41) surfaces were more likely than fingertips to remain heavily contaminated after handwashing.
Handwashing with soap and water showed the greatest efficacy in removing C. difficile and should be performed preferentially over the use of alcohol-based handrubs when contact with C. difficile is suspected or likely.
Using whole genome sequencing of isolates from a cohort of patients with Clostridium difficile infection (CDI) and colonization, we found that incident CDI cases were more likely to be linked to an ...infected than colonized donor.
Abstract
Background
Whole genome sequencing (WGS) studies can enhance our understanding of the role of patients with asymptomatic Clostridium difficile colonization in transmission.
Methods
Isolates obtained from patients with Clostridium difficile infection (CDI) and colonization identified in a study conducted during 2006-2007 at 6 Canadian hospitals underwent typing by pulsed-field gel electrophoresis, multilocus sequence typing, and WGS. Isolates from incident CDI cases not in the initial study were also sequenced where possible. Ward movement and typing data were combined to identify plausible donors for each CDI case, as defined by shared time and space within predefined limits. Proportions of plausible donors for CDI cases that were colonized, infected, or both were examined.
Results
Five hundred fifty-four isolates were sequenced successfully, 353 from colonized patients and 201 from CDI cases. The NAP1/027/ST1 strain was the most common strain, found in 124 (62%) of infected and 92 (26%) of colonized patients. A donor with a plausible ward link was found for 81 CDI cases (40%) using WGS with a threshold of ≤2 single nucleotide polymorphisms to determine relatedness. Sixty-five (32%) CDI cases could be linked to both infected and colonized donors. Exclusive linkages to infected and colonized donors were found for 28 (14%) and 12 (6%) CDI cases, respectively.
Conclusions
Colonized patients contribute to transmission, but CDI cases are more likely linked to other infected patients than colonized patients in this cohort with high rates of the NAP1/027/ST1 strain, highlighting the importance of local prevalence of virulent strains in determining transmission dynamics.
Rectal swabs are routinely used by public health authorities to screen for multi-drug resistant enteric bacteria including vancomycin-resistant enterococci (VRE) and carbapenem-resistant ...enterobacteriaceae (CRE). Screening sensitivity can be influenced by the quality of the swabbing, whether performed by the patient (self-swabbing) or a healthcare practitioner. One common exclusion criterion for rectal swabs is absence of “visible soiling” from fecal matter. In our institution, this criterion excludes almost 10% of rectal swabs received in the microbiology laboratory. Furthermore, over 30% of patients in whom rectal swabs are cancelled will not be re-screened within the next 48h, resulting in delays in removing infection prevention measures. We describe two quantitative polymerase chain reaction (qPCR)-based assays, human RNAse P and eubacterial 16S rDNA, which might serve as suitable controls for sampling adequacy. However, lower amounts of amplifiable human DNA make the 16s rDNA assay a better candidate for sample adequacy control.
Quantitative PCR (qPCR) is a leading screening tool, permitting rapid detection of pathogens and the maintenance of effective infection control programs. Unfortunately, qPCR assays frequently do not ...incorporate Sample Adequacy Control (SAC). A SAC controls for the quantity, quality and adequacy of the specimen. Without SAC, the confidence in a negative result remains questionable and the efficacy of screening is compromised. Ultimately, the exclusion of SAC from qPCR may result in false negative results. One should consider SAC to be an integral critical type of laboratory control; addressing diverse analytical problems, such as sample adequacy, sample processing and assay inhibition. Following distribution of cycle threshold values (Cq) of Influenza A positive results and Cq values of SAC, obtained from nasopharyngeal swabs, we showed that the confidence in a negative result cannot be guaranteed in the presence of a weak positive SAC signal (late Cq values). Herein, we explain why widespread inclusion of sample adequacy control in routine screening is blocked. A protocol and methods for SAC threshold establishment are offered.
Sample Adequacy Control (SAC) has critical analytical, clinical and epidemiological value that increases confidence in a negative test result. The SAC is an integral qPCR assay control, which ensures ...that all pre-analytical and analytical steps are adequate for accurate testing and reporting. As such, a negative SAC with a negative result on pathogen screen specifies that the result should be reported as inconclusive instead of negative. Despite this, many regulatory approved tests do not incorporate SAC into their assay design. Herein, we emphasize the universal value of SAC and offer for the first time, a simple technical strategy to introduce non-competitive SAC which does not interfere with the limit of detection for the screened pathogen. Integration of SAC can provide key benefits towards identifying, isolating, quarantining and contact tracing infected individuals and in turn can improve worldwide efforts in infection control.
Respiratory screening assays lacking Sample Adequacy Controls (SAC) may result in inadequate sample quality and thus false negative results. The non-adequate samples might represent a significant ...proportion of the total performed tests, thus resulting in sub-optimal infection control measures with implications that may be critical during pandemic times. The quantitative sample adequacy threshold can be established empirically, measuring the change in the frequency of positive results, as a function of the numerical value of "sample adequacy". Establishing a quantitative threshold for SAC requires a big number/volume of tests to be analyzed in order to have a statistically valid result. Herein, we are offering for the first time clear clinical evidence that a subset of results, which did not pass minimal sample adequacy criteria, have a significantly lower frequency of positivity compared with the "adequate" samples. Flagging these results and/or re-sampling them is a mitigation strategy, which can dramatically improve infection control measures.
Seasonal influenza causes significant morbidity and mortality, primarily due to increased complication rates among the elderly population and patients with chronic diseases. Timely diagnosis of ...influenza and early recognition of an influenza outbreak or epidemic are key components in preventing influenza-related complications, hospitalizations, and deaths. Emergency departments are the most frequent points of entry for most influenza cases and are well positioned to identify and manage influenza community outbreaks and epidemics. Emergency departments need specific infection control measures to curb the spread of influenza in the Emergency Department and hospital during the influenza season.
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