biomArker-guided Duration of Antibiotic treatment in hospitalised Patients with suspecTed Sepsis (ADAPT-Sepsis): A protocol for a multicentre randomised controlled trial.

Aim: To describe the protocol for a multi-centre randomised controlled trial to determine whether treatment protocols monitoring daily CRP (C-reactive protein) or PCT (procalcitonin) safely allow a reduction in duration of antibiotic therapy in hospitalised adult patients with sepsis. Design: Multicentre three-arm randomised controlled trial. Setting: UK NHS hospitals. Target population: Hospitalised critically ill adults who have been commenced on intravenous antibiotics for sepsis. Health technology: Three protocols for guiding antibiotic discontinuation will be compared: (a) standard care; (b) standard care + daily CRP monitoring; (c) standard care + daily PCT monitoring. Standard care will be based on routine sepsis management and antibiotic stewardship. Measurement of outcomes and costs. Outcomes will be assessed to 28 days. The primary outcomes are total duration of antibiotics and safety outcome of all-cause mortality. Secondary outcomes include: escalation of care/re-admission; infection re-lapse/recurrence; antibiotic dose; length and level of critical care stay and length of hospital stay. Ninety-day all-cause mortality rates will also be collected. An assessment of cost effectiveness will be performed. Conclusion: In the setting of routine NHS care, if this trial finds that a treatment protocol based on monitoring CRP or PCT safely allows a reduction in duration of antibiotic therapy, and is cost effective, then this has the potential to change clinical practice for critically ill patients with sepsis. Moreover, if a biomarker-guided protocol is not found to be effective, then it will be important to avoid its use in sepsis and prevent ineffective technology becoming widely adopted in clinical practice.

Disease Recurrence and Long-term Outcomes Following the Development of Intestinal Failure in Crohn's Disease: Over 20 Years of Experience from a National Reference Centre.

BACKGROUND AND AIMS: Intestinal failure [IF] is a recognised complication of Crohn's disease [CD]. The aim of this study was to identify factors predicting the development and recurrence of CD in patients with IF [CD-IF], and their long-term outcomes. METHODS: This was a cohort study of adults with CD-IF admitted to a national UK IF reference centre between 2000 and 2021. Patients were followed from discharge with home parenteral nutrition [HPN] until death or February 28, 2021. RESULTS: In all, 124 patients were included; 47 [37.9%] changed disease location and 55 [44.4%] changed disease behaviour between CD and CD-IF diagnosis, with increased upper gastrointestinal involvement [4.0% vs 22.6% patients], p <0.001. Following IF diagnosis, 29/124 [23.4%] patients commenced CD prophylactic medical therapy; 18 [62.1%] had a history of stricturing or penetrating small bowel disease; and nine [31.0%] had ileocolonic phenotype brought back into continuity. The cumulative incidence of disease recurrence was 2.4% at 1 year, 16.3% at 5 years and 27.2% at 10 years; colon-in-continuity and prophylactic treatment were associated with an increased likelihood of disease recurrence. Catheter-related bloodstream infection [CRBSI] rate was 0.32 episodes/1000 catheter days, with no association between medical therapy and CRBSI rate. CONCLUSIONS: This is the largest series reporting disease behaviour and long-term outcomes in CD-IF and the first describing prophylactic therapy use. The incidence of disease recurrence was low. Immunosuppressive therapy appears to be safe in HPN-dependent patients with no increased risk of CRBSI. The management of CD-IF needs to be tailored to the patient's surgical disease history alongside disease phenotype.

Impact of negative pressure wound therapy on enteroatmospheric fistulation in the septic open abdomen.

AIM: The effect of negative pressure wound therapy (NPWT) on the pathogenesis and outcome of enteroatmospheric fistulation (EAF) in the septic open abdomen (OA) is unclear. This study compares the development and outcome of EAF following NPWT with that occurring in the absence of NPWT. METHODS: Consecutive patients admitted with EAF following abdominal sepsis at a National Reference Centre for intestinal failure between 01 January 2005 and 31 December 2015 were included in this study. Patients were divided into two groups based on those that had been treated with NPWT and those that had not (non-NPWT) and characteristics of their fistulas compared. Clinical outcomes concerning nutritional autonomy at 4 years and time to fistula development, size of abdominal wall defect and complete fistula closure were compared between groups. RESULTS: A total of 160 patients were admitted with EAF following a septic abdomen (31-NPWT and 129-non-NPWT). Median (range) time taken to fistulation after OA was longer with NPWT (18 [5-113] vs. 8 [2-60] days, p = 0.004); these patients developed a greater number of fistulas (3 [2-21] vs. 2 [1-10], p = 0.01), involving a greater length of small bowel (42.5 [15-100] cm vs. 30 [3.5-170] cm, p = 0.04) than those who did not receive NPWT. Following reconstructive surgery, nutritional autonomy was similar in both groups (77% vs. 72%) and a comparable number of patients were also fistula-free (100% vs. 97%). CONCLUSIONS: Negative pressure wound therapy appears to be associated with more complex and delayed intestinal fistulation, involving a greater length of small intestine in the septic OA. This did not, however, appear to adversely affect the overall outcome of intestinal and abdominal wall reconstruction in this study.

Standardised survival and excess Life Years Lost in patients with type 3 intestinal failure.

BACKGROUND & AIMS: Long term outcomes have been reported in home parenteral nutrition (HPN)-dependent patients with type 3 intestinal failure (IF), but there are limited survival data standardised to the general population that would help provide a meaningful prognosis for patients and clinicians. The primary aim of this study was therefore to investigate the survival of HPN-dependent patients and to evaluate the specific impact of type 3 IF on their life expectancy standardised to that of the general population. METHODS: This was a cohort study of adult patients initiated on HPN between 1978 and 2018 at a national UK IF reference centre and followed up until death or censoring date of 31st December 2020. The standardised mortality ratio (SMR) was calculated as observed deaths divided by expected deaths using UK Office for National Statistics database. Excess Life Years Lost (LYL) were calculated separately for each sex as the differences in average life expectancy between patients with type 3 IF and the general population. Survival data were evaluated using cox regression models adjusting for confounding. RESULTS: In total, 1046 patients were identified, with a total observation time of 7344.1 patient-years. Patients with malignancy (n = 206) were excluded from the survival analysis. Of the remaining 840 patients, 398 were alive by the end of follow-up. The probability of survival was 91.8% at 1 year, 69.3% at 5 years, 54.3% at 10 years, 29.8% at 20 years and 16.7% at 30 years. Patients who did not achieve nutritional autonomy had an increased likelihood of death compared to patients who ceased HPN. In total, 40 (9.0%) deaths were HPN or IF-related, while underlying disease leading to IF accounted for 98 (22.2%) deaths. There were 270 (61.1%) deaths not related to IF, with the majority of these patients dying from infections unrelated to HPN. Overall mortality rates were higher among patients with a diagnosis of type 3 IF compared with the general UK population with a SMR of 7.48 (95% CI 6.80 to 8.21) and an excess mortality rate of 54.0 per 1000 person-years. All mechanisms of IF were associated with excess mortality, with SMR ranging from 6.82 (95% CI 5.98 to 7.72) for short bowel syndrome to 15.51 (95% CI 11.73 to 20.03) for dysmotility. On average, the excess LYL was 17.45 years for males and 17.39 years for females compared with the general population of the same age. CONCLUSION: This the largest single-centre series reporting survival outcomes in patients with type 3 IF over more than a four-decade period and the first to report LYL in this patient cohort. Type 3 IF was associated with more than seven-fold higher mortality rates than for the general UK population and shorter life expectancies of more than 17 years. Survival, however, was better in those able to achieve nutritional autonomy. Since the majority of deaths were due to non-HPN or non-IF causes, there is clearly a need now to further explore these causes of death in order to improve our understanding of excessive mortality in type 3 IF and develop ways to prevent it.

A comparison between thoracic epidural analgesia and rectus sheath catheter analgesia after open midline major abdominal surgery: randomized clinical trial.

BACKGROUND: Rectus sheath catheter analgesia (RSCA) and thoracic epidural analgesia (TEA) are both used for analgesia following laparotomy. The aim was to compare the analgesic effectiveness of RSCA with TEA after laparotomy for elective colorectal and urological surgery. METHODS: Patients undergoing elective midline laparotomy were randomized in a non-blinded fashion to receive RSCA or TEA for postoperative analgesia at a single UK teaching hospital. The primary quantitative outcome measure was dynamic pain score at 24 h after surgery. A nested qualitative study (reported elsewhere) explored the dual primary outcome of patient experience and acceptability. Secondary outcome measures included rest and movement pain scores over 72 h, functional analgesia, analgesia satisfaction, opiate consumption, functional recovery, morbidity, safety, and cost-effectiveness. RESULTS: A total of 131 patients were randomized: 66 in the RSCA group and 65 in the TEA group. The median (interquartile range; i.q.r.) dynamic pain score at 24 h was significantly lower after TEA than RSCA (33 (11-60) versus 50.5 (24.50-77.25); P = 0.018). Resting pain score at 72 h was significantly lower after RSCA (4.5 (0.25-13.75) versus 12.5 (2-13); P = 0.019). Opiate consumption on postoperative day 3 (median (i.q.r.) morphine equivalent 17 (10-30) mg versus 40 (13.25-88.50) mg; P = 0.038), hypotension, or vasopressor dependency (29.7 versus 49.2 per cent; P = 0.023) and weight gain to day 3 (median (i.q.r.) 0 (-1-2) kg versus 1 (0-3) kg; P = 0.046) were all significantly greater after TEA, compared with RSCA. There were no significant differences between groups in other secondary outcomes, although more participants experienced serious adverse events after TEA compared with RSCA, which was also the more cost-effective. CONCLUSIONS: TEA provided superior initial postoperative analgesia but only for the first 24 h. By 72 hours RSCA provides superior analgesia, is associated with a lower incidence of unwanted effects, and may be more cost-effective.

Long-Term Outcomes in Patients with Intestinal Failure Due to Short Bowel Syndrome and Intestinal Fistula.

Short bowel syndrome (SBS) and enterocutaneous or enteroatmospheric fistulas are common indications for home parenteral nutrition (HPN). However, there are few data describing factors influencing surgical decision-making or outcomes particularly following fistula development. We aimed to compare outcomes between patients with SBS and fistulas and explore surgical decision-making. HPN-dependent adults from 2001−2018 at a national reference centre were included in this study. HPN cessation was analysed using death as competing risk. In total, 465 patients (SBS (62%), fistula (38%)) were included, with median HPN dependency of 2.6 years. In total, 203 patients underwent reconstructive surgery; while frailty was the commonest reason for not undergoing surgery (49.2%), 22.7% declined surgery. Overall, 170 ceased HPN, with a probability of 13.8%, 34.1% and 38.3% at 1, 5 and 10 years, respectively. Patients undergoing surgery had higher nutritional autonomy rates (109.8 incidences/1000 patient years) compared to those not undergoing surgery (18.1 incidences/1000 patient years; p < 0.001). A total of 295 patients (63.4%) were predicted to cease HPN based on gastrointestinal anatomy but only 162/295 (54.9%) achieved this; those unable to do so were older with a higher comorbidity index. There were no differences in long-term nutritional and survival outcomes or surgical decisions between patients with SBS and fistulas, or between enterocutaneous and enteroatmospheric fistulas. This study represents one of the largest datasets describing the ability of HPN-dependent patients with SBS or fistulas to achieve nutritional autonomy. While reconstructive surgery facilitates HPN cessation, approximately one-fifth of patients declined surgery despite HPN dependency. These data will better inform patient expectation and help plan alternative therapies.

Quantification of Proteins Involved in Intestinal Epithelial Handling of Xenobiotics.

The intestinal epithelium represents a natural barrier against harmful xenobiotics, while facilitating the uptake of nutrients and other substances. Understanding the interaction of chemicals with constituents of the intestinal epithelium and their fate in the body requires quantitative measurement of relevant proteins in in vitro systems and intestinal epithelium. Recent studies have highlighted the mismatch between messenger RNA (mRNA) and protein abundance for several drug-metabolizing enzymes and transporters in the highly dynamic environment of the intestinal epithelium; mRNA abundances cannot therefore be used as a proxy for protein abundances in the gut, necessitating direct measurements. The objective was to determine the expression of a wide range proteins pertinent to metabolism and disposition of chemicals and nutrients in the intestinal epithelium. Ileum and jejunum biopsy specimens were obtained from 16 patients undergoing gastrointestinal elective surgery. Mucosal fractions were prepared and analyzed using targeted and global proteomic approaches. A total of 29 enzymes, 32 transporters, 6 tight junction proteins, 2 adhesion proteins, 1 alkaline phosphatase, 1 thioredoxin, 5 markers, and 1 regulatory protein were quantified-60 for the first time. The global proteomic method identified a further 5,222 proteins, which are retained as an open database for interested parties to explore. This study significantly expands our knowledge of a wide array of proteins important for xenobiotic handling in the intestinal epithelium. Quantitative systems biology models will benefit from the novel systems data generated in the present study and the translation path offered for in vitro to in vivo translation.

Causes and Prognosis of Intestinal Failure in Crohn's Disease: An 18-year Experience From a National Centre.

BACKGROUND AND AIMS: Intestinal failure [IF] is a feared complication of Crohn's disease [CD]. Although cumulative loss of small bowel due to bowel resections is thought to be the dominant cause, the causes and outcomes have not been reported. METHODS: Consecutive adult patients referred to a national intestinal failure unit over 2000-2018 with a diagnosis of CD, and subsequently treated with parenteral nutrition during at least 12 months, were included in this longitudinal cohort study. Data were extracted from a prospective institutional clinical database and patient records. RESULTS: A total of 121 patients were included. Of these, 62 [51%] of patients developed IF as a consequence of abdominal sepsis complicating abdominal surgery; small bowel resection, primary disease activity, and proximal stoma were less common causes [31%, 12%, and 6%, respectively]. Further, 32 had perianastomotic sepsis, and 15 of those had documented risk factors for anastomotic dehiscence. On Kaplan-Meier analysis, 40% of all patients regained nutritional autonomy within 10 years and none did subsequently; 14% of patients developed intestinal failure-associated liver disease. On Kaplan-Meier analysis, projected mean age of death was 74 years.2. CONCLUSIONS: IF is a severe complication of CD, with 60% of patients permanently dependent on parenteral nutrition. The most frequent event leading directly to IF was a septic complication following abdominal surgery, in many cases following intestinal anastomosis in the presence of significant risk factors for anastomotic dehiscence. A reduced need for abdominal surgery, an increased awareness of perioperative risk factors, and structured pre-operative optimisation may reduce the incidence of IF in CD.

Quantitative Proteomics of Clinically Relevant Drug-Metabolizing Enzymes and Drug Transporters and Their Intercorrelations in the Human Small Intestine.

The levels of drug-metabolizing enzymes (DMEs) and transporter proteins in the human intestine are pertinent to determine oral drug bioavailability. Despite the paucity of reports on such measurements, it is well recognized that these values are essential for translating in vitro data on drug metabolism and transport to predict drug disposition in gut wall. In the current study, clinically relevant DMEs [cytochrome P450 (P450) and uridine 5'-diphospho-glucuronosyltransferase (UGT)] and drug transporters were quantified in total mucosal protein preparations from the human jejunum (n = 4) and ileum (n = 12) using quantification concatemer-based targeted proteomics. In contrast to previous reports, UGT2B15 and organic anion-transporting polypeptide 1 (OATP1A2) were quantifiable in all our samples. Overall, no significant disparities in protein expression were observed between jejunum and ileum. Relative mRNA expression for drug transporters did not correlate with the abundance of their cognate protein, except for P-glycoprotein 1 (P-gp) and organic solute transporter subunit alpha (OST-α), highlighting the limitations of RNA as a surrogate for protein expression in dynamic tissues with high turnover. Intercorrelations were found within P450 [2C9-2C19 (P = 0.002, R 2 = 0.63), 2C9-2J2 (P = 0.004, R 2 = 0.40), 2D6-2J2 (P = 0.002, R 2 = 0.50)] and UGT [1A1-2B7 (P = 0.02, R 2 = 0.87)] family of enzymes. There were also correlations between P-gp and several other proteins [OST-α (P < 0.0001, R 2 = 0.77), UGT1A6 (P = 0.009, R 2 = 0.38), and CYP3A4 (P = 0.007, R 2 = 0.30)]. Incorporating such correlations into building virtual populations is crucial for obtaining plausible characteristics of simulated individuals. SIGNIFICANCE STATEMENT: A number of drug transporters were quantified for the first time in this study. Several intercorrelations of protein abundance were reported. mRNA expression levels proved to be a poor reflection of differences between individuals regarding the level of protein expression in gut. The reported abundance of drug-metabolizing enzymes and transporters and their intercorrelations will contribute to better predictions of oral drug bioavailability and drug-drug interactions by linking in vitro observations to potential outcomes through physiologically based pharmacokinetic models.

Regulation of Peritoneal Inflammatory Response to Implant Material Using an Ex Vivo Model System.

BACKGROUND: Implants used in abdominal wall reconstruction are associated with intra-abdominal inflammation that can cause complications such as adhesions, fistulae, or failure of the implant. This study analyzed the inflammatory response of human peritoneum explants when exposed to different implant materials including synthetic and biological (cross-linked and non-cross-linked). MATERIALS AND METHODS: Human peritoneum explants (parietal and visceral) were incubated in culture with implants used for abdominal wall reconstruction. Implants included Permacol (biological implant with chemical cross-linking); Biodesign and Strattice (biological implants without chemical cross-linking); Prolene (synthetic nonabsorbable); and Vicryl (synthetic absorbable). Control peritoneum samples were incubated without implant. Cytokine concentrations and corresponding gene expression were measured by enzyme-linked immunosorbent assay and quantitative polymerase chain reaction, respectively. Further evaluation included assessment of tissue viability and implant-cytokine adsorption. RESULTS: Incubation of human peritoneal explants with Biodesign or Strattice was associated with a significant reduction in interleukin-6, interleukin-1ß, and tumour necrosis factor alpha protein and gene expression compared with control. These could not be explained by reduced cell viability or implant-cytokine adsorption. Incubation of explants in Biodesign-conditioned media displayed a similar effect to incubation of explants with Biodesign itself. CONCLUSIONS: Human peritoneal explants cultured with different mesh implant materials show an altered inflammatory cytokine response suggesting a tissue-specific response. Downregulation of key inflammatory cytokines by the peritoneum exposed to non-cross-linked biological implants may be mediated by the release of soluble factors from these implants inhibiting cytokine gene expression. This ex vivo human peritoneal system provides a novel preclinical model to investigate peritoneum-implant interactions.

Cholelithiasis and Related Morbidity in Chronic Intestinal Failure: a Longitudinal Cohort Study from a National Specialized Centre.

BACKGROUND: Short-term studies have shown that patients with type III intestinal failure often develop gallstones and have recommended prophylactic cholecystectomy. In this retrospective cohort study, we aimed to define the incidence and clinical consequences of cholelithiasis over an extended time period, in order to refine the role of prophylactic cholecystectomy in type III intestinal failure. METHODS: Data were retrospectively collected from a prospectively maintained audit. Patients with intestinal failure for 5 years or more were included. Kaplan-Meier analysis was used to estimate cumulative incidence over time. Predictors of cholelithiasis were evaluated by Cox regression. RESULTS: Between 1 January 1983 and 1 December 2008, 81 patients were commenced on parenteral support lasting 5 years or more. Of 63 patients with no pre-existing gallstones on imaging, 17 (27%) developed gallstones during a median observation period of 133 months. On Kaplan-Meier analysis, the incidence at 10 years was 21%; at 20 years, 38%; and at 30 years, 47%. Thirteen of the 17 had symptoms and ten required surgical and/or endoscopic intervention. Increased weekly calorific content (P 0.003) and the provision of parenteral lipids (P 0.003) were predictors of cholelithiasis on univariable Cox regression. CONCLUSION: Many patients with long-term intestinal failure develop gallstones over time, with a 20-year incidence of 38%. The majority of those have symptoms or complications and require intervention. Therefore, prophylactic en-passant cholecystectomy is justified when gallstones are present in type III intestinal failure, supporting routine pre-operative imaging of the gallbladder prior to abdominal surgery.

Use of Anal Acoustic Reflectometry in the Evaluation of Men With Passive Fecal Leakage.

BACKGROUND: Men with passive fecal leakage represent a distinct clinical entity in which the pathophysiology remains unclear. Standard anorectal investigations fail to demonstrate consistent abnormalities in this group. Anal acoustic reflectometry is a new test of anal sphincter function with greater sensitivity and discriminatory ability than conventional anal manometry. OBJECTIVE: The aim of this study was to determine whether men with fecal leakage have an abnormality in anal sphincter function that is detectable by anal acoustic reflectometry. DESIGN: This was an age-matched study of continent and incontinent men. SETTINGS: The study was conducted at a university teaching hospital. PATIENTS: Male patients with isolated symptoms of fecal leakage were recruited. Anal acoustic reflectometry, followed by conventional anal manometry, was performed. Results were then compared with those from an age-matched group of men with no symptoms of anal incontinence or anorectal pathology. MAIN OUTCOME MEASURES: Variables measured with anal acoustic reflectometry and anal manometry in the incontinent and continent men were compared. RESULTS: Thirty subjects were recruited, of whom 15 were men with fecal leakage and 15 were continent men. There was a significantly higher incidence of previous anorectal surgery in the men with leakage. The anal acoustic reflectometry variables of opening and closing pressure were significantly lower in leakers compared with continent subjects (p = 0.003 and p = 0.001). Hysteresis was significantly greater in the male leaker group (p = 0.026). No difference was seen in anal manometry. LIMITATIONS: With a larger sample size, the effect of previous anorectal surgery and the presence of an anal sphincter defect could be clarified. CONCLUSIONS: Anal acoustic reflectometry is a sensitive test of anal sphincter function and, unlike anal manometry, can discriminate male leakers from continent subjects. An identifiable abnormality has been detected using anal acoustic reflectometry, which may further our understanding of the pathogenesis in this group.

Survival and nutritional dependence on home parenteral nutrition: Three decades of experience from a single referral centre.

BACKGROUND: Home parenteral nutrition (HPN) is the mainstay of treatment for patients with Type 3 intestinal failure (IF), however long term data on mortality and nutritional outcomes are limited. OBJECTIVES: To assess the long-term survival and requirements for ongoing HPN in patients receiving treatment at a UK national referral centre for intestinal failure. METHODS: Patients with IF who received HPN for more than 3 months at this Intestinal Failure Unit between 1978 and 2011 had their clinical records reviewed. SPSS 20 was utilised to perform Cox regression analysis and generate Kaplan Meier curves, with the aim of identifying factors associated with death and the continued need for HPN. RESULTS: Case notes from 545 patients were reviewed. Overall survival (OS) in patients without malignancy at commencement of IF was 93%, 71%, 59% and 28% at 1, 5, 10 and 20 years after starting treatment. Crohn's disease, mesenteric ischaemia and chronic intestinal pseudo-obstruction were associated with a better OS than scleroderma and radiation enteritis on multivariate analysis. Older age at onset of IF was associated with poor OS, while shorter small bowel length or central line sepsis was not. 15% (25/170) of deaths were due to complications of HPN (central line sepsis = 10, IF-associated liver disease = 15). Continued HPN dependence in survivors was 83%, 63%, 59% and 53% at 1, 5, 10 and 15 years, respectively. Among the 153 patients without malignancy who achieved nutritional independence from HPN, 77 (50.3%) did so after surgical reconstruction of the alimentary tract (HPN duration mean 19 months, range 3-126 months). 76 patients (49.7%) weaned from HPN without undergoing surgical reconstruction. CONCLUSION: This is the largest reported data set on long-term survival and dependence on HPN and will inform the indications, benefits and risks of treatment in disease specific groups. A significant proportion of patients achieved nutritional autonomy without surgical intervention.

In Vitro-In Vivo Extrapolation Scaling Factors for Intestinal P-glycoprotein and Breast Cancer Resistance Protein: Part II. The Impact of Cross-Laboratory Variations of Intestinal Transporter Relative Expression Factors on Predicted Drug Disposition.

Relative expression factors (REFs) are used to scale in vitro transporter kinetic data via in vitro-in vivo extrapolation linked to physiologically based pharmacokinetic (IVIVE-PBPK) models to clinical observations. Primarily two techniques to quantify transporter protein expression are available, immunoblotting and liquid chromatography-tandem mass spectrometry. Literature-collated REFs ranged from 0.4 to 5.1 and 1.1 to 90 for intestinal P-glycoprotein (P-gp) and breast cancer resistance protein (BCRP), respectively. The impact of using human jejunum-Caco-2 REFs for P-gp (REFiP-gp) and BCRP (REFiBCRP), generated from the same samples and using different proteomic methodologies from independent laboratories, on PBPK outcomes was assessed. A 5-fold decrease in REFiP-gp for a single oral dose of digoxin resulted in a 1.19- and 1.31-fold higher plasma area under the curve and Cmax, respectively. All generated REFiP-gp values led to simulated digoxin Cmax values within observed ranges; however, combining kinetic data generated from a different laboratory with the 5-fold lower REFiP-gp could not recover a digoxin-rifampicin drug-drug interaction, emphasizing the necessity to obtain transporter-specific kinetic estimates and REFs from the same in vitro system. For a theoretical BCRP compound, with absorption taking place primarily in the jejunum, a decrease in the REFiBCRP from 2.22 (University of Manchester) to 1.11 (Bertin Pharma) promoted proximal intestinal absorption while delaying tmax 1.44-fold. Laboratory-specific differences in REF may lead to different IVIVE-PBPK outcomes. To understand the mechanisms underlying projected pharmacokinetic liabilities, it is important to assess the potential impact of bias on the generation of REFs on an interindividual basis within a target population.

In Vitro-In Vivo Extrapolation Scaling Factors for Intestinal P-Glycoprotein and Breast Cancer Resistance Protein: Part I: A Cross-Laboratory Comparison of Transporter-Protein Abundances and Relative Expression Factors in Human Intestine and Caco-2 Cells.

Over the last 5 years the quantification of transporter-protein absolute abundances has dramatically increased in parallel to the expanded use of in vitro-in vivo extrapolation (IVIVE) and physiologically based pharmacokinetics (PBPK)-linked models, for decision-making in pharmaceutical company drug development pipelines and regulatory submissions. Although several research groups have developed laboratory-specific proteomic workflows, it is unclear if the large range of reported variability is founded on true interindividual variability or experimental variability resulting from sample preparation or the proteomic methodology used. To assess the potential for methodological bias on end-point abundance quantification, two independent laboratories, the University of Manchester (UoM) and Bertin Pharma (BPh), employing different proteomic workflows, quantified the absolute abundances of Na/K-ATPase, P-gp, and breast cancer resistance protein (BCRP) in the same set of biologic samples from human intestinal and Caco-2 cell membranes. Across all samples, P-gp abundances were significantly correlated (P = 0.04, Rs = 0.72) with a 2.4-fold higher abundance (P = 0.001) generated at UoM compared with BPh. There was a systematically higher BCRP abundance in Caco-2 cell samples quantified by BPh compared with UoM, but not in human intestinal samples. Consequently, a similar intestinal relative expression factor (REF), derived from distal jejunum and Caco-2 monolayer samples, between laboratories was found for P-gp. However, a 2-fold higher intestinal REF was generated by UoM (2.22) versus BPh (1.11). We demonstrate that differences in absolute protein abundance are evident between laboratories and they probably result from laboratory-specific methodologies relating to peptide choice.

Central Venous Catheter Salvage in Home Parenteral Nutrition Catheter-Related Bloodstream Infections: Long-Term Safety and Efficacy Data.

BACKGROUND: Catheter-related bloodstream infections (CRBSIs) are a serious complication in the provision of home parenteral nutrition (HPN). Antibiotic salvage of central venous catheters (CVCs) in CRBSI is recommended; however, this is based on limited reports. We assessed the efficacy of antibiotic salvage of CRBSIs in HPN patients. MATERIALS AND METHODS: All confirmed CRBSIs occurring in patients receiving HPN in a national intestinal failure unit (IFU), between 1993 and 2011, were analyzed. A standardized protocol involving antibiotic and urokinase CVC locks and systemic antibiotics was used. RESULTS: In total, 588 patients were identified with a total of 2134 HPN years, and 297 CRBSIs occurred in 137 patients (65 single and 72 multiple CRBSIs). The overall rate of CRBSI in all patients was 0.38 per 1000 catheter days. Most (87.9%) infections were attributable to a single microorganism. In total, 72.5% (180/248) of CRBSIs were salvaged when attempted (coagulase-negative staphylococcus, 79.8% [103/129], Staphylococcus aureus, 56.7% [17/30]; polymicrobial infections, 67.7% [21/30]; and miscellaneous, 66.1% [39/59]). CVC salvage was not attempted in 49 episodes because of life-threatening sepsis (n = 18), fungal infection (n = 7), catheter problems (n = 20), and CVC tunnel infection (n = 4). Overall, the CVC was removed in 33.7% (100/297) of cases. There were 5 deaths in patients admitted to the IFU for management of the CRBSI (2 severe sepsis at presentation, 3 metastatic infection). CONCLUSIONS: This is the largest reported series of catheter salvage in CRBSIs and demonstrates successful catheter salvage in most cases when using a standardized protocol.

Rapid detection of health-care-associated bloodstream infection in critical care using multipathogen real-time polymerase chain reaction technology: a diagnostic accuracy study and systematic review.

BACKGROUND: There is growing interest in the potential utility of real-time polymerase chain reaction (PCR) in diagnosing bloodstream infection by detecting pathogen deoxyribonucleic acid (DNA) in blood samples within a few hours. SeptiFast (Roche Diagnostics GmBH, Mannheim, Germany) is a multipathogen probe-based system targeting ribosomal DNA sequences of bacteria and fungi. It detects and identifies the commonest pathogens causing bloodstream infection. As background to this study, we report a systematic review of Phase III diagnostic accuracy studies of SeptiFast, which reveals uncertainty about its likely clinical utility based on widespread evidence of deficiencies in study design and reporting with a high risk of bias. OBJECTIVE: Determine the accuracy of SeptiFast real-time PCR for the detection of health-care-associated bloodstream infection, against standard microbiological culture. DESIGN: Prospective multicentre Phase III clinical diagnostic accuracy study using the standards for the reporting of diagnostic accuracy studies criteria. SETTING: Critical care departments within NHS hospitals in the north-west of England. PARTICIPANTS: Adult patients requiring blood culture (BC) when developing new signs of systemic inflammation. MAIN OUTCOME MEASURES: SeptiFast real-time PCR results at species/genus level compared with microbiological culture in association with independent adjudication of infection. Metrics of diagnostic accuracy were derived including sensitivity, specificity, likelihood ratios and predictive values, with their 95% confidence intervals (CIs). Latent class analysis was used to explore the diagnostic performance of culture as a reference standard. RESULTS: Of 1006 new patient episodes of systemic inflammation in 853 patients, 922 (92%) met the inclusion criteria and provided sufficient information for analysis. Index test assay failure occurred on 69 (7%) occasions. Adult patients had been exposed to a median of 8 days (interquartile range 4-16 days) of hospital care, had high levels of organ support activities and recent antibiotic exposure. SeptiFast real-time PCR, when compared with culture-proven bloodstream infection at species/genus level, had better specificity (85.8%, 95% CI 83.3% to 88.1%) than sensitivity (50%, 95% CI 39.1% to 60.8%). When compared with pooled diagnostic metrics derived from our systematic review, our clinical study revealed lower test accuracy of SeptiFast real-time PCR, mainly as a result of low diagnostic sensitivity. There was a low prevalence of BC-proven pathogens in these patients (9.2%, 95% CI 7.4% to 11.2%) such that the post-test probabilities of both a positive (26.3%, 95% CI 19.8% to 33.7%) and a negative SeptiFast test (5.6%, 95% CI 4.1% to 7.4%) indicate the potential limitations of this technology in the diagnosis of bloodstream infection. However, latent class analysis indicates that BC has a low sensitivity, questioning its relevance as a reference test in this setting. Using this analysis approach, the sensitivity of the SeptiFast test was low but also appeared significantly better than BC. Blood samples identified as positive by either culture or SeptiFast real-time PCR were associated with a high probability (> 95%) of infection, indicating higher diagnostic rule-in utility than was apparent using conventional analyses of diagnostic accuracy. CONCLUSION: SeptiFast real-time PCR on blood samples may have rapid rule-in utility for the diagnosis of health-care-associated bloodstream infection but the lack of sensitivity is a significant limiting factor. Innovations aimed at improved diagnostic sensitivity of real-time PCR in this setting are urgently required. Future work recommendations include technology developments to improve the efficiency of pathogen DNA extraction and the capacity to detect a much broader range of pathogens and drug resistance genes and the application of new statistical approaches able to more reliably assess test performance in situation where the reference standard (e.g. blood culture in the setting of high antimicrobial use) is prone to error. STUDY REGISTRATION: The systematic review is registered as PROSPERO CRD42011001289. FUNDING: The National Institute for Health Research Health Technology Assessment programme. Professor Daniel McAuley and Professor Gavin D Perkins contributed to the systematic review through their funded roles as codirectors of the Intensive Care Foundation (UK).