Rapid identification and quantification of Campylobacter coli and Campylobacter jejuni by real-time PCR in pure cultures and in complex samples

<p>Abstract</p> <p>Background</p> <p><it>Campylobacter </it>spp., especially <it>Campylobacter jejuni </it>(<it>C. jejuni</it>) and <it>Campylobacter coli </it>(<it>C. coli</it>), are recognized as the leading human foodborne pathogens in developed countries. Livestock animals carrying <it>Campylobacter </it>pose an important risk for human contamination. Pigs are known to be frequently colonized with <it>Campylobacter</it>, especially <it>C. coli</it>, and to excrete high numbers of this pathogen in their faeces. Molecular tools, notably real-time PCR, provide an effective, rapid, and sensitive alternative to culture-based methods for the detection of <it>C. coli </it>and <it>C. jejuni </it>in various substrates. In order to serve as a diagnostic tool supporting <it>Campylobacter </it>epidemiology, we developed a quantitative real-time PCR method for species-specific detection and quantification of <it>C. coli </it>and <it>C. jejuni </it>directly in faecal, feed, and environmental samples.</p> <p>Results</p> <p>With a sensitivity of 10 genome copies and a linear range of seven to eight orders of magnitude, the <it>C. coli </it>and <it>C. jejuni </it>real-time PCR assays allowed a precise quantification of purified DNA from <it>C. coli </it>and <it>C. jejuni</it>. The assays were highly specific and showed a 6-log-linear dynamic range of quantification with a quantitative detection limit of approximately 2.5 × 10²CFU/g of faeces, 1.3 × 10²CFU/g of feed, and 1.0 × 10³CFU/m²for the environmental samples. Compared to the results obtained by culture, both <it>C. coli </it>and <it>C. jejuni </it>real-time PCR assays exhibited a specificity of 96.2% with a kappa of 0.94 and 0.89 respectively. For faecal samples of experimentally infected pigs, the coefficients of correlation between the <it>C. coli </it>or <it>C. jejuni </it>real-time PCR assay and culture enumeration were R²= 0.90 and R²= 0.93 respectively.</p> <p>Conclusion</p> <p>The <it>C. coli </it>and <it>C. jejuni </it>real-time quantitative PCR assays developed in this study provide a method capable of directly detecting and quantifying <it>C. coli </it>and <it>C. jejuni </it>in faeces, feed, and environmental samples. These assays represent a new diagnostic tool for studying the epidemiology of <it>Campylobacter </it>by, for instance, investigating the carriage and excretion of <it>C. coli </it>and <it>C. jejuni </it>by pigs from conventional herds.</p

Control of Salmonella environmental contamination during

This study aims at investigating Salmonella environmental contamination of trucks and lairage pens and evaluating the efficiency of an improved cleaning and disinfection protocol to reduce Salmonella environmental contamination. During four days, the lairage of two French pig slaughterhouses were sampled twice a day when pigs were present and once at the end of the week after the cleaning protocol. In parallel, six trucks per day were randomly selected and sampled at their arrival and after the cleaning procedure. The samples consisted of floor surface swabbing. Salmonella occurrence, level of contamination and serotypes were determined. The efficiency of different cleaning and disinfection procedures on the presence of Salmonella was also estimated. Salmonella was isolated in 97.7% of the lairage samples when pigs were present (contamination levels \u3e104UFC/m2) and in 65% of the truck samples (contamination levels from \u3c10 to \u3e104UFC/m2). An improved cleaning and disinfection procedure reduced efficiently the occurrence and the level of contamination in the trucks (almost 100%) compared to a simple wash with cold water (no effect), more partially in the lairage. This study showed the importance of a good cleaning and disinfection protocol to decrease the level of contamination or eliminate the bacteria in the trucks used for the transport of pigs

A practice-related risk score (PRS): a DOPPS-derived aggregate quality index for haemodialysis facilities

Background. The Dialysis Outcomes and Practice Patterns Study (DOPPS) database was used to develop and validate a practice-related risk score (PRS) based on modifiable practices to help facilities assess potential areas for improving patient care. Methods. Relative risks (RRs) from a multivariable Cox mortality model, based on observational haemodialysis (HD) patient data from DOPPS I (1996-2001, seven countries), were used. The four practices were the percent of patients with Kt/V >= 1.2, haemoglobin >= 11 g/dl (110 g/l), albumin >= 4.0 g/dl (40g/l) and catheter use, and were significantly related to mortality when modelled together. DOPPS II data (2002-2004, 12 countries) were used to evaluate the relationship between PRS and mortality risk using Cox regression. Results. For facilities in DOPPS I and II, changes in PRS over time were significantly correlated with changes in the standardized mortality ratio (SMR). The PRS ranged from 1.0 to 2.1. Overall, the adjusted RR of death was 1.05 per 0.1 points higher PRS (P < 0.0001). For facilities in both DOPPS I and II (N = 119), a 0.2 decrease in PRS was associated with a 0.19 decrease in SMR (P = 0.005). On average, facilities that improved PRS practices showed significantly reduced mortality over the same time frame. Conclusions. The PRS assesses modifiable HD practices that are linked to improved patient survival. Further refinements might lead to improvements in the PRS and will address regional variations in the PRS/mortality relationship

Ability of Lactobacillus fermentum to overcome host α-galactosidase deficiency, as evidenced by reduction of hydrogen excretion in rats consuming soya α-galacto-oligosaccharides

<p>Abstract</p> <p>Background</p> <p>Soya and its derivatives represent nutritionally high quality food products whose major drawback is their high content of α-galacto-oligosaccharides. These are not digested in the small intestine due to the natural absence of tissular α-galactosidase in mammals. The passage of these carbohydrates to the large intestine makes them available for fermentation by gas-producing bacteria leading to intestinal flatulence. The aim of the work reported here was to assess the ability of α-galactosidase-producing lactobacilli to improve the digestibility of α-galacto-oligosaccharides <it>in situ</it>.</p> <p>Results</p> <p>Gnotobiotic rats were orally fed with soy milk and placed in respiratory chambers designed to monitor fermentative gas excretion. The validity of the animal model was first checked using gnotobiotic rats monoassociated with a <it>Clostridium butyricum </it>hydrogen (H₂)-producing strain. Ingestion of native soy milk by these rats caused significant H₂emission while ingestion of α-galacto-oligosaccharide-free soy milk did not, thus validating the experimental system. When native soy milk was fermented using the α-galactosidase-producing <it>Lactobacillus fermentum </it>CRL722 strain, the resulting product failed to induce H₂emission in rats thus validating the bacterial model. When <it>L. fermentum </it>CRL722 was coadministered with native soy milk, a significant reduction (50 %, <it>P </it>= 0.019) in H₂emission was observed, showing that α-galactosidase from <it>L. fermentum </it>CRL722 remained active <it>in situ</it>, in the gastrointestinal tract of rats monoassociated with <it>C. butyricum</it>. In human-microbiota associated rats, <it>L. fermentum </it>CRL722 also induced a significant reduction of H₂emission (70 %, <it>P </it>= 0.004).</p> <p>Conclusion</p> <p>These results strongly suggest that <it>L. fermentum </it>α-galactosidase is able to partially alleviate α-galactosidase deficiency in rats. This offers interesting perspectives in various applications in which lactic acid bacteria could be used as a vector for delivery of digestive enzymes in man and animals.</p

Prevention of catheter lumen occlusion with rT-PA versus heparin (Pre-CLOT): study protocol of a randomized trial [ISRCTN35253449]

BACKGROUND: Many patients with end-stage renal disease use a central venous catheter for hemodialysis access. A large majority of these catheters malfunction within one year of insertion, with up to two-thirds due to thrombosis. The optimal solution for locking the catheter between hemodialysis sessions, to decrease the risk of thrombosis and catheter malfunction, is unknown. The Prevention of Catheter Lumen Occlusion with rt-PA versus Heparin (PreCLOT) study will determine if use of weekly rt-PA, compared to regular heparin, as a catheter locking solution, will decrease the risk of catheter malfunction. METHODS/DESIGN: The study population will consist of patients requiring chronic hemodialysis thrice weekly who are dialyzed with a newly inserted permanent dual-lumen central venous catheter. Patients randomized to the treatment arm will receive rt-PA 1 mg per lumen once per week, with heparin 5,000 units per ml as a catheter locking solution for the remaining two sessions. Patients randomized to the control arm will receive heparin 5,000 units per ml as a catheter locking solution after each dialysis session. The study treatment period will be six months, with 340 patients to be recruited from 14 sites across Canada. The primary outcome will be catheter malfunction, based on mean blood flow parameters while on hemodialysis, with a secondary outcome of catheter-related bacteremia. A cost-effectiveness analysis will be undertaken to assess the cost of maintaining a catheter using rt-PA as a locking solution, compared to the use of heparin. DISCUSSION: Results from this study will determine if use of weekly rt-PA, compared to heparin, will decrease catheter malfunction, as well as assess the cost-effectiveness of these locking solutions

EXACKTE2: Exploiting the clinical consultation as a knowledge transfer and exchange environment: a study protocol

Background While the evidence suggests that the way physicians provide information to patients is crucial in helping patients decide upon a course of action, the field of knowledge translation and exchange (KTE) is silent about how the physician and the patient influence each other during clinical interactions and decision-making. Consequently, based on a novel relationship-centered model, EXACKTE2 (EXploiting the clinicAl Consultation as a Knowledge Transfer and Exchange Environment), this study proposes to assess how patients and physicians influence each other in consultations. Methods We will employ a cross-sectional study design involving 300 pairs of patients and family physicians from two primary care practice-based research networks. The consultation between patient and physician will be audio-taped and transcribed. Following the consultation, patients and physicians will complete a set of questionnaires based on the EXACKTE2 model. All questionnaires will be similar for patients and physicians. These questionnaires will assess the key concepts of our proposed model based on the essential elements of shared decision-making (SDM): definition and explanation of problem; presentation of options; discussion of pros and cons; clarification of patient values and preferences; discussion of patient ability and self-efficacy; presentation of doctor knowledge and recommendation; and checking and clarifying understanding. Patients will be contacted by phone two weeks later and asked to complete questionnaires on decisional regret and quality of life. The analysis will be conducted to compare the key concepts in the EXACKTE2 model between patients and physicians. It will also allow the assessment of how patients and physicians influence each other in consultations. Discussion Our proposed model, EXACKTE2, is aimed at advancing the science of KTE based on a relationship process when decision-making has to take place. It fosters a new KTE paradigm by putting forward a relationship-centered perspective and has the potential to reveal unknown mechanisms that underline effective KTE in clinical contexts. This will result in better understanding of the mechanisms that may promote a new generation of knowledge transfer strategies