The significance of lead entering the human food chain via livestock ingestion from the agricultural use of biosolids, with special reference to the UK

Long-term application of biosolids to agricultural soil results in the slow accumulation of potentially toxic elements (PTEs), which are regulated by maximum permitted limit values to protect human health and the environment. Two programmes of UK government-funded (MAFF/DoE) research were commissioned in the 1990s to investigate the safety of the controls on PTEs in relation to the potential transfer to the food chain via the animal ingestion route by sheep grazing biosolids-amended soil. Here, we re-examine this evidence in the light of other recent research and revised food quality standards, to determine the significance of lead (Pb) accumulation in soil from the agricultural use of biosolids. Direct ingestion of biosolids-amended soil is the main transfer pathway of Pb to grazing livestock. The concentrations of Pb in muscle tissue of animals grazing biosolids-amended soil observed in the MAFF/DoE trials, and reported in the scientific literature, were generally small and similar to background, control values. Lambs and ewes ingesting biosolids-amended soil with a total Pb concentration > 200 mg kg-1 dry soil at a rate of 10 % in the diet exceeded the current maximum permitted concentration of Pb in offal (0.5 mg kg-1 fresh weight). However, the decline in PTE concentrations found in biosolids, due to improved industrial practices and stricter controls on the emissions of contaminants to the environment in general and wastewater in particular, has mitigated the risk of Pb accumulation above the food quality standard for this element in offal. Given the significant improvements in biosolids quality, and particularly in the Pb content, regulatory soil and sludge limits for Pb are no longer likely to have a practical or significant impact on the amount of Pb entering the food chain through the animal ingestion route from biosolids-amended agricultural soil.

Do contaminants compromise the use of recycled nutrients in organic agriculture? A review and synthesis of current knowledge on contaminant concentrations, fate in the environment and risk assessment

Use of nutrients recycled from societal waste streams in agriculture is part of the circular economy, and in line with organic farming principles. Nevertheless, diverse contaminants in waste streams create doubts among organic farmers about potential risks for soil health. Here, we gather the current knowledge on contaminant levels in waste streams and recycled nutrient sources, and discuss associated risks. For potentially toxic elements (PTEs), the input of zinc (Zn) and copper (Cu) from mineral feed supplements remains of concern, while concentrations of PTEs in many waste streams have decreased substantially in Europe. The same applies to organic contaminants, although new chemical groups such as flame retardants are of emerging concern and globally contamination levels differ strongly. Compared to inorganic fertilizers, application of organic fertilizers derived from human or animal feces is associated with an increased risk for environmental dissemination of antibiotic resistance. The risk depends on the quality of the organic fertilizers, which varies between geographical regions, but farmland application of sewage sludge appears to be a safe practice as shown by some studies (e.g. from Sweden). Microplastic concentrations in agricultural soils show a wide spread and our understanding of its toxicity is limited, hampering a sound risk assessment. Methods for assessing public health risks for organic contaminants must include emerging contaminants and potential interactions of multiple compounds. Evidence from long-term field experiments suggests that soils may be more resilient and capable to degrade or stabilize pollutants than often assumed. In view of the need to source nutrients for expanding areas under organic farming, we discuss inputs originating from conventional farms vs. non-agricultural (i.e. societal) inputs. Closing nutrient cycles between agriculture and society is feasible in many cases, without being compromised by contaminants, and should be enhanced, aided by improved source control, waste treatment and sound risk assessments.

Influence of the bile acid/microbiota axis in ileal surgery: a systematic review

AIM

The gastrointestinal bile acid (BA)/microbiota axis has emerged as a potential mediator of health and disease, particularly in relation to pathologies such as inflammatory bowel disease (IBD) and colorectal cancer. Whilst it presents an exciting new avenue for therapies, it has not yet been characterized in surgical resection of the ileum, where BA reabsorption occurs. The identification of BA/microbiota signatures may provide future therapies with perioperative personalized medicine. In this work we conduct a systematic review with the aim of investigating the microbiome and BA changes that are associated with resection of the ileum.

METHOD

The databases included were MEDLINE, EMBASE, Web of Science and Cochrane libraries. The outcomes of interest were faecal microbiome and BA signatures after ileal resection.

RESULTS

Of the initial 3106 articles, three studies met the inclusion/exclusion criteria for data extraction. A total of 257 patients (46% surgery, 54% nonsurgery controls) were included in the three studies. Two studies included patients with short bowel syndrome and the other included patients with IBD. Large-scale microbiota changes were reported. In general, alpha diversity had decreased amongst patients with ileal surgery. Phylum-level changes included decreased Bacteroidetes and increased Proteobacteria and Fusobacteria in patients with an intestinal resection. Surgery was associated with increased total faecal BAs, cholic acid and chenodeoxycholic acid. There were decreases in deoxycholic acid and glycine and taurine conjugated bile salts. Integrated BA and microbiota data identified correlations with several bacterial families and BA.

CONCLUSION

The BA/microbiota axis is still a novel area with minimal observational data in surgery. Further mechanistic research is necessary to further explore this and identify its role in improving perioperative outcomes.

Optimal antiseptic skin preparation agents for minimizing surgical site infection following surgery: cost and cost-effectiveness analysis

BACKGROUND

The application of antiseptic skin agents prior to incision minimizes the rate of surgical site infection. Despite their ubiquity, the optimal skin preparation agent remains uncertain. A retrospective economic analysis was conducted to complement the results from the NEWSkin Prep trial which prospectively compared three preparation agents.

METHODS

A cost and cost-effectiveness analysis was performed from a healthcare service perspective to compare chlorhexidine with 70% ethanol, and aqueous povidone-iodine, against povidone-iodine with 70% ethanol. Resource use estimates accounted for hospital admissions, readmissions associated with surgical site infection, outpatient and general practitioner attendances, visits from community nurses and therapeutic consumables. The measure of effectiveness comprised the net difference in number of patients with surgical site infections per 1000 patients. Costs were compared using a two-sample Welch's t-test. Deterministic and probabilistic sensitivity analyses were performed to evaluate the incremental cost-effectiveness ratio.

RESULTS

The null hypothesis that the mean costs for the trial arms were significantly different was not rejected (Welch's t-test P value: 0.771 for chlorhexidine with 70% ethanol against povidone-iodine with 70% ethanol; and 0.955 for aqueous povidone-iodine against povidone-iodine with 70% ethanol). Based on bootstrap averages, the chlorhexidine with 70% ethanol intervention generated 8.0 fewer surgical site infections per 1000 patients and net cost savings of €151,698 (Euros) per 1000 patients compared with povidone-iodine with 70% ethanol, and aqueous povidone-iodine produced a net cost saving of €37,494 per 1000 patients but generated an additional 11.6 surgical site infections per 1000 patients compared with povidone-iodine with 70% ethanol. The comparison of chlorhexidine with 70% ethanol to povidone-iodine with 70% ethanol was sensitive to the inclusion of cost outliers, while the comparison of aqueous povidone-iodine to povidone-iodine with 70% ethanol was sensitive to the estimated cost per surgical site infection.

CONCLUSION

Based on the outcomes from the NEWSkin Prep study, this economic analysis found no definitive evidence in favour of any one of the study comparators. Future model-based economic analyses of alternative skin preparations should critically address the quality of evidence and integrate the results from the NEWSkin Prep study.

A pilot study: intraoperative 16S rRNA sequencing versus culture in predicting colorectal incisional surgical site infection

BACKGROUND

Surgical Site Infection (SSI) of the abdominal incision is a dreaded complication following colorectal surgery. Identifying the intraoperative surgical site microbes may provide clarity in the pathogenesis of SSIs. Genomic sequencing has revolutionized the ability to identify microbes from clinical samples. Utilization of 16S rRNA amplicon sequencing to characterize the intraoperative surgical site may provide the critical information required to predict and prevent infection in colorectal surgery.

METHODS

This is a pilot, prospective observational study of 50 patients undergoing elective colorectal resection. At completion of surgery, prior to skin closure, swabs were taken from the subcutaneous tissue of the abdominal incision to investigate the microbial profile. Dual swabs were taken to compare standard culture technique and 16S rRNA sequencing to establish if a microbial profile was associated with postoperative SSI.

RESULTS

8/50 patients developed an SSI, which was more likely in those undergoing open surgery (5/15 33.3% versus 3/35, 8.6%; P = 0.029). 16S rRNA amplicon sequencing was more sensitive in microbial detection compared to traditional culture. Both culture and 16S rRNA demonstrated contamination of the surgical site, predominantly with anaerobes. Culture was not statistically predictive of infection. 16S rRNA amplicon sequencing was not statistically predictive of infection, however, it demonstrated patients with an SSI had an increased biodiversity (not significant) and a greater relative abundance (not significant) of pathogens such as Bacteroidacaea and Enterobacteriaceae within the intraoperative site.

CONCLUSIONS

16S rRNA amplicon sequencing has demonstrated a potential difference in the intraoperative microbial profile of those that develop an infection. These findings require validation through powered experiments to determine the overall clinical significance.

Venous thromboembolic prophylaxis: current practice of surgeons in Australia and New Zealand for major abdominal surgery

BACKGROUND

Surgical prophylaxis for venous thrombo-embolic disease (VTE) includes risk assessment, chemical prophylaxis and mechanical prophylaxis (graduated compression stockings [GCS] and/or intermittent pneumatic compression devices [IPCD]). Although there is overwhelming evidence for the need and efficacy of VTE prophylaxis in patients at risk, only about a third of those who are at risk of VTE receive appropriate prophylaxis.

OBJECTIVE

There is debate as to the best combination of VTE prophylaxis following abdominal surgery due to lack of evidence. The aim of this survey was to understand this gap between knowledge and practice.

METHODS

In 2019 and 2020, a survey was conducted to investigate the current practice of venous thromboembolism (VTE) prophylaxis for major abdominal surgery, with a focus on colorectal resections. The study received ethics approval and involved distributing an 11-item questionnaire to members of two professional surgical societies: the Colorectal Surgical Society of Australia and New Zealand (CSSANZ) and the General Surgeons Australia (GSA).

RESULTS

From 214 surgeons: 100% use chemical prophylaxis, 68% do not use a risk assessment tool, 27% do not vary practice according to patient risk factors while > 90% use all three forms of VTE prophylaxis at some stage of treatment. Most surgeons do not vary practice between laparoscopic and open colectomy/major abdominal surgery and only 33% prescribe post-discharge chemical prophylaxis. 42% of surgeons surveyed had equipoise for a clinical trial on the use of IPCDs and the vast majority (> 95%) feel that IPCDs should provide at least a 2% improvement in VTE event rate in order to justify their routine use.

CONCLUSION

Most surgeons in Australia and New Zealand do not use risk assessment tools and use all three forms of prophylaxis regardless. Therfore there is a gap between practice and VTE prophylaxis for the use of mechanical prophylaxis options. Further research is required to determine whether dual modality mechanical prophylaxis is incrementally efficacious. Trial Registration- Not Applicable.

Topical Lidocaine or Lidocaine/Diltiazem Ointment Following Rubber Band Ligation of Hemorrhoids: A Prospective 3-Armed Randomized Controlled Trial

BACKGROUND

Rubber band ligation of hemorrhoids causes less pain than excisional hemorrhoidectomy, but many patients still experience significant postprocedure discomfort.

OBJECTIVE

This study aimed to determine whether topical lidocaine, with or without diltiazem, is more effective than placebo for analgesia after hemorrhoid banding.

DESIGN

This is a prospective, randomized, double-blinded, placebo-controlled trial. Patients were randomly assigned to 2% lidocaine, 2% lidocaine with 2% diltiazem, or a placebo ointment.

SETTINGS

This study was performed at 2 university public teaching hospitals and 2 private hospitals in Australia.

PATIENTS

Consecutive patients aged ≥18 years undergoing hemorrhoid banding were selected.

INTERVENTIONS

Topical ointments were applied postprocedure 3× daily for 5 days.

MAIN OUTCOME MEASURES

Visual analog pain score, opiate analgesia usage, and patient satisfaction were the main outcome measures.

RESULTS

Of 159 eligible patients, 99 were randomly assigned (33 in each group). Pain scores were reduced at 1 hour for the lidocaine (OR 4.15 [1.12-15.41]; p = 0.03) and lidocaine/diltiazem groups (OR 3.85 [1.05-14.11]; p = 0.04) compared with placebo. Patients in the lidocaine/diltiazem group had improved satisfaction (OR 3.82 [1.28-11.44]; p = 0.02) and were more likely to recommend the procedure to others (OR 9.33 [1.07-81.72]; p = 0.04). Patients in the lidocaine/diltiazem group required approximately 45% less total and in-hospital analgesia compared with the placebo. There was no difference in complications between any of the groups.

LIMITATIONS

A cost/benefit analysis was not performed. Analgesic efficacy appeared to be short term and the procedures were performed only in the hospital/nonambulatory setting.

CONCLUSIONS

Topical lidocaine reduced short-term analgesia use, whereas combination lidocaine/diltiazem was associated with both improved analgesia and patient satisfaction after hemorrhoid banding.

LIDOCANA TPICA O UNGENTO DE LIDOCANA/DILTIAZEM DESPUS DE LA LIGADURA HEMORROIDAL CON BANDA ELSTICA UN ENSAYO PROSPECTIVO CONTROLADO Y ALEATORIZADO DE TRES BRAZOS

ANTECEDENTES:La ligadura de hemorroides con banda elástica causa menos dolor que la hemorroidectomía escisional, pero muchos pacientes siguen experimentando molestias significativas tras el procedimiento.OBJETIVO:Este estudio tiene como objetivo determinar si la lidocaína tópica, con o sin diltiazem, es más eficaz que el placebo para la analgesia tras la ligadura hemorroidal.DISEÑO:Este es un ensayo prospectivo, aleatorizado, doble ciego, controlado con placebo. Los pacientes fueron aleatorizados para recibir lidocaína al 2 %, lidocaína al 2 % con diltiazem al 2 % o ungüento de placebo.AJUSTES:Este estudio se realizó en dos hospitales públicos con docencia universitaria y dos hospitales privados en Australia.PACIENTES:Se seleccionaron pacientes consecutivos de ≥18 años sometidos a ligadura para hemorroides.INTERVENCIONES:Se aplicaron ungüentos tópicos tras el procedimiento tres veces al día durante 5 días.PRINCIPALES MEDIDAS DE RESULTADO:La puntuación analógica visual del dolor, el uso de analgésicos opiáceos y la satisfacción del paciente fueron las principales medidas de resultado.RESULTADOS:De 159 pacientes elegibles, 99 fueron aleatorizados (33 en cada grupo). Las puntuaciones de dolor se redujeron a la hora para los grupos de lidocaína (OR 4,15 (1,12-15,41); p = 0,03) y lidocaína/diltiazem (OR 3,85 (1,05-14,11), p = 0,04) en comparación con el placebo.Los pacientes del grupo de lidocaína/diltiazem mejoraron su satisfacción (OR 3,82 (1,28-11,44), p = 0,02) y eran más propensos de recomendar el procedimiento a otros (OR 9,33 (1,07-81,72), p = 0,04). Los pacientes del grupo de lidocaína/diltiazem requirieron aproximadamente un 45 % menos de analgesia total e intrahospitalaria en comparación con el grupo de placebo. No hubo diferencia en las complicaciones entre ninguno de los grupos.LIMITACIONES:No se realizó un análisis de costo/beneficio. La eficacia analgésica pareció ser a corto plazo y los procedimientos solo se realizaron en el hospital/entorno no ambulatorio.CONCLUSIÓN:La lidocaína tópica mejora la analgesia a corto plazo, mientras que la combinación de lidocaína/diltiazem se asocia tanto con una mejor analgesia como con la satisfacción del paciente tras la colocación de bandas para hemorroides. (Traducción-Dr Osvaldo Gauto ).

Cross-Linked Enzyme Aggregate (CLEA) Preparation from Waste Activated Sludge

Enzymes are used extensively as industrial bio-catalysts in various manufacturing and processing sectors. However, commercial enzymes are expensive in part due to the high cost of the nutrient medium for the biomass culture. Activated sludge (AS) is a waste product of biological wastewater treatment and consists of microbial biomass that degrades organic matter by producing substantial quantities of hydrolytic enzymes. Recovering enzymes from AS therefore offers a potential alternative to conventional production techniques. A carrier-free, cross-linked enzyme aggregate (CLEA) was produced from crude AS enzyme extract for the first time. A major advantage of the CLEA is the combined immobilization, purification, and stabilization of the crude enzymes into a single step, thereby avoiding large amounts of inert carriers in the final enzyme product. The AS CLEA contained a variety of hydrolytic enzymes and demonstrated high potential for the bio-conversion of complex organic substrates.

Transfer of polychlorinated, brominated and mixed-halogenated dioxins, furans and biphenyls, polychlorinated naphthalenes and alkanes, polycyclic aromatic hydrocarbons and chlorobenzenes to the milk of dairy cattle from controlled ingestion of industrial and municipal bioresources recycled to agricultural land

Recycled bioresources (biosolids, compost-like-output, meat and bonemeal ash, poultry litter ash, paper sludge ash) were added to the feed of dairy cattle to simulate incidental ingestion from agricultural utilisation, to investigate the transfer of organic contaminants from the ingested materials to milk. The bioresources were blended with a loamy sand soil at agronomic rates to simulate a single application to land, which was added to the diet at 5 % of the total intake on a dry matter (DM) basis. Biosolids, and control treatments consisting of unamended soil, were also added directly to the feed at 5 % DM. The cattle were fed the bioresource amended diets for a target period of three to four weeks, depending on material, and monitoring continued for four weeks after treatment withdrawal. Milk samples were taken weekly with chemical analysis of selected samples for a range of organic contaminants including: polychlorinated, polybrominated and mixed-halogenated dioxins, furans and biphenyls, polychlorinated naphthalenes and alkanes (often called chlorinated paraffins), polycyclic aromatic hydrocarbons and chlorobenzenes. No statistically significant additional transfer of organic contaminants to the milk was detected when bioresources were blended with soil due to the relatively low levels of contaminants present when the bioresources were blended with soil at agronomic rates. However, direct biosolids ingestion by cattle significantly increased the transfer of contaminants to milk in comparison to control animals. Although present in larger concentrations in biosolids than their chlorinated counterparts, the carry over rates and bioconcentration factors for brominated dioxins and furans were considerably smaller. Direct ingestion of biosolids resulted in most contaminants approaching, but not always completely reaching, steady state concentrations within the treatment feeding period, however, concentrations generally declined to control values within four-weeks after withdrawing the biosolids-amended diet.

A Systematic Review and Meta-Analysis of Intra-Operative Surgical Site Sampling: Culture versus Culture-Independent Techniques in Predicting Downstream Surgical Site Infection

Background: Surgical site infection remains a significant cause of morbidity and mortality. Traditionally, the causation has been inferred from the organism(s) detected in the post-operative setting. However, the intra-operative surgical site and the bacteria it harbors have been scarcely studied. Compared with culture-dependent methods, the development of genomic technology provides a new sensitive tool that could aid in characterizing the bacteria within the surgical site. The purpose of this literature review is to establish if there is a predictive role of sampling the intra-operative surgical site. Methods: A systematic literature review was conducted identifying relevant literature reporting on studies that sampled the intra-operative surgical site of any specialty, using either traditional culture or a culture-independent genomic sequencing-based technique and correlation with infection was attempted. The review identified studies between 1959 and 2021 in MEDLINE, EMBASE and Cochrane. Results: The initial search identified 7,835 articles; 36 remained after screening. Thirty-one articles focused on culture-dependent techniques, five on culture-independent. Subgroup meta-analysis demonstrates that a positive intra-operative culture carries a risk of downstream infection with an odds ratio of 8.6, however limited by a high false-positive and inability to correlate the intra-operative culture with the post-operative infection. In contrast, culture-independent studies through genomic sequencing are not predictive but suggest that the surgical incision is a complex microbial community with a shift toward dysbiosis in certain patients. Conclusion: The intra-operative surgical site clearly harbors bacteria. Both techniques give rise to separate explanations underpinning the role of bacteria in surgical site infection. It is possible there is a more complex dynamic community within the incision that makes a patient susceptible to infection. Characterizing this microbial community in large scale studies, including patients with infections may enhance our ability to predict and prevent incisional surgical site infections in patients undergoing surgical procedures.

C1q and mobility score in predicting sarcopenia in an Australian cohort of cancer surgery patients

BACKGROUND

Sarcopenia has been shown to have significant adverse health outcomes in a range of patient populations. Particularly, sarcopenic patients having cancer surgery are a unique group who demonstrate poorer post-operative outcomes. Currently, the gold standard in diagnosing sarcopenia is through the use of computed tomography. However, the widespread use of imaging to diagnose patients with sarcopenia is neither cost-effective nor practical. Identifying a serum biomarker or a simple mobility scoring system as an alternative diagnostic tool may aid in identifying more patients at risk of sarcopenia. C1q, a novel biomarker, has previously been shown to correlate with sarcopenia. Similarly, we sought to explore whether mobility scores may provide a useful surrogate marker for sarcopenia.

METHODS

This was a prospective cohort study of patients who presented for colorectal cancer surgery between the dates of 6/10/2016 and 4/10/2017 at John Hunter Hospital. Computed tomography was utilized to calculate the psoas area at the L3 spinal level. Pre-operative blood samples were obtained for C1q analysis and de Morton Mobility Index (DEMMI) was also performed.

RESULTS

A total of 51 patients were included in the study. The median age of the patients were 69 years old. We did not demonstrate a correlation between serum C1q and DEMMI scores with psoas area.

CONCLUSION

Our findings suggest that neither C1q nor DEMMI scores are correlated with psoas area in a colorectal cancer population.

The effect of preoperative skin preparation on clinical outcomes with incisional surgery: a network meta-analysis

BACKGROUND

Preoperative skin antiseptics are used prior to surgery to reduce the risk of surgical site infection (SSI). There is debate as to which is the most effective. The aim of this network meta-analysis (NMA) is to compare the effectiveness of different skin preparations at reducing SSIs in patients undergoing incisional surgery.

METHODS

The study protocol was published in PROSPERO (CRD4202181599) a priori with predefined search terms and inclusion/exclusion criteria. The skin preparations for comparison were: chlorhexidine/alcohol (CHA), chlorhexidine/water (CHW), poviodine/alcohol (PVIA), poviodine/water (PVIW). The records identified were screened by two authors independently by title, abstract and in full text. The revised tool for risk-of bias (ROB2) assessment was used.

RESULTS

Twenty-nine RCTs involving 15 796 patients were included in the NMA. A significant but small increase in the odds of infection was seen in the PVIW group compared to the CHA group (OR 1.34, 95%CrI 1.09-1.64), but other comparisons were not statistically significantly different. Ranking the treatment arms showed there was a 64% probability that CHA is the most effective and a 62.7% probability that PVIW is the least effective treatment.

CONCLUSION

Chlorhexidine/alcohol (CHA) was found to be the most effective for prevention of superficial and deep SSI while PVIW was the least. There was no differences seen between CHA and PVIA, or CHW and PVIW. The superiority of CHA is likely due to the effect of the alcohol in the base. Hence the choice between CHA and PVIA should be based on health and cost considerations.

The link between organic matter composition and the biogas yield of full-scale sewage sludge anaerobic digestion

The principal parameters influencing anaerobic digestion (AD) of sewage sludge have been extensively studied in controlled laboratory experiments, but the effects of sludge composition on full-scale systems have received relatively little attention. Sludge samples from eight major wastewater treatment plants (WWTPs) in the UK were examined to determine the effects of sludge composition on digestion performance. The biogas yield (BY) was estimated by two different methods: (1) a standard approach based on the reduction in volatile solids (VS), and (2) a more detailed mass balance of major constituent fractions of organic matter in sludge. The results showed that BY increased significantly with the overall amount of VS contained in digester feed sludge. In terms of the effects of individual fractions, BY was significantly related to and increased with the fat and cellulose contents in raw sludge, consistent with the high calorific value of fat and the digestibilities of both substrates, relative to the other major organic components. The results demonstrated the importance of sludge composition on digester performance and strategies to maximise BY were identified, for instance, by increasing codigestion of high fat containing substrates, and by utilising fat, oil and grease collected in-sewer and at WWTP.

Caloric restriction in humans reveals immunometabolic regulators of health span

The extension of life span driven by 40% caloric restriction (CR) in rodents causes trade-offs in growth, reproduction, and immune defense that make it difficult to identify therapeutically relevant CR-mimetic targets. We report that about 14% CR for 2 years in healthy humans improved thymopoiesis and was correlated with mobilization of intrathymic ectopic lipid. CR-induced transcriptional reprogramming in adipose tissue implicated pathways regulating mitochondrial bioenergetics, anti-inflammatory responses, and longevity. Expression of the gene Pla2g7 encoding platelet activating factor acetyl hydrolase (PLA2G7) is inhibited in humans undergoing CR. Deletion of Pla2g7 in mice showed decreased thymic lipoatrophy, protection against age-related inflammation, lowered NLRP3 inflammasome activation, and improved metabolic health. Therefore, the reduction of PLA2G7 may mediate the immunometabolic effects of CR and could potentially be harnessed to lower inflammation and extend the health span.

Concentrations of organic contaminants in industrial and municipal bioresources recycled in agriculture in the UK

Many types of bioresource materials are beneficially recycled in agriculture for soil improvement and as alternative bedding materials for livestock, but they also potentially transfer contaminants into plant and animal foods. Representative types of industrial and municipal bioresources were selected to assess the extent of organic chemical contamination, including: (i) land applied materials: treated sewage sludge (biosolids), meat and bone meal ash (MBMA), poultry litter ash (PLA), paper sludge ash (PSA) and compost-like-output (CLO), and (ii) bedding materials: recycled waste wood (RWW), dried paper sludge (DPS), paper sludge ash (PSA) and shredded cardboard. The materials generally contained lower concentrations of polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (PCBs) relative to earlier reports, indicating the decline in environmental emissions of these established contaminants. However, concentrations of polycyclic aromatic hydrocarbons (PAHs) remain elevated in biosolids samples from urban catchments. Polybrominated dibenzo-p-dioxins/dibenzofurans (PBDD/Fs) were present in larger amounts in biosolids and CLO compared to their chlorinated counterparts and hence are of potentially greater significance in contemporary materials. The presence of non-ortho-polychlorinated biphenyls (PCBs) in DPS was probably due to non-legacy sources of PCBs in paper production. Flame retardent chemicals were one of the most significant and extensive groups of contaminants found in the bioresource materials. Decabromodiphenylether (deca-BDE) was the most abundant polybrominated diphenyl ether (PBDE) and may explain the formation and high concentrations of PBDD/Fs detected. Emerging flame retardant compounds, including: decabromodiphenylethane (DBDPE) and organophosphate flame retardants (OPFRs), were also detected in several of the materials. The profile of perfluoroalkyl substances (PFAS) depended on the type of waste category; perfluoroundecanoic acid (PFUnDA) was the most significant PFAS for DPS, whereas perfluorooctane sulfonate (PFOS) was dominant in biosolids and CLO. The concentrations of polychlorinated alkanes (PCAs) and di-2-ethylhexyl phthalate (DEHP) were generally much larger than the other contaminants measured, indicating that there are major anthropogenic sources of these potentially hazardous chemicals entering the environment. The study results suggest that continued vigilance is required to control emissions and sources of these contaminants to support the beneficial use of secondary bioresource materials.

The significance of cadmium entering the human food chain via livestock ingestion from the agricultural use of biosolids, with special reference to the UK

When biosolids are applied to agricultural soil, potentially toxic elements (PTEs) accumulate in the topsoil, although it takes many repeated applications to reach soil limit values. Two programmes of UK government-funded research were commissioned in the 1990s to investigate the transfer of PTEs to the food chain via ingestion by sheep grazing biosolids-amended soil. Here, we critically re-examine this evidence in the light of other published work and current food quality standards. This was particularly motivated by the need to determine the safety of biosolids controls on PTEs in relation to revised and stricter European food quality controls for PTEs in foodstuffs. The major pathway for transfer of PTEs to grazing livestock is via direct ingestion of biosolids or biosolids-amended soil from the soil surface. The main elements of concern for the human diet are cadmium (Cd) and lead (Pb), with Cd being the focus of the current paper. Animal ingestion of plant tissue is also a potential pathway for Cd exposure, which, unlike Pb, can transfer to crop tissues. The concentrations of Cd in the muscle tissue of sheep grazing biosolids-amended soil were generally small and similar to control values. Cadmium concentrations in sheep offal were below the maximum permitted concentration for human consumption. This was despite ingestion of soils exceeding the maximum permissible concentration for Cd in soil (3 mg kg^-1 dry soil) by up to three times, at an ingestion rate of 10% total dietary dry matter intake. Grazing trials under practical conditions on high Cd soils demonstrated that the Cd concentrations in sheep offal remained below the food limit value for this element in offal from the combined intakes from biosolids-amended soil and herbage. Futhermore, given the substantial fall in environmental emissions and concentrations in biosolids of this element and, consequently, it cannot accumulate in soil to the limit value, biosolids Cd does not represent an issue for the safety of animal meat products.

A systematic scoping review on natural killer cell function in colorectal cancer

PURPOSE

Natural Killer (NK) cells are a vital part of immune surveillance and have been implicated in colorectal cancer development and prognosis. This systematic review aims to distil the literature on NK cells as it relates to colorectal cancer.

METHODS

All published studies over 10 years relating to NK cells and colorectal cancer were reviewed. All studies publishing in English, searchable via pubmed or through reference review and reporting directly on the nature or function of NK cells in colorectal cancer patients were included. Outcomes were determined as alterations or new information regarding NK cells in colorectal cancer patients.

RESULTS

Natural killer cells may be implicated in the development of colorectal cancer and may play a role in prognostication of the disease. NK cells are altered by the treatment (both surgical and medical) of colorectal cancer and it seems likely that they will also be a target for manipulation to improve colorectal cancer survival.

CONCLUSIONS

NK cell morphology and function are significantly affected by the development of colorectal cancer. Observation of NK cell changes may lead to earlier detection and better prognostication in colorectal cancer. Further study is needed into immunological manipulation of NK cells which may lead to improved colorectal cancer survival.

C-reactive protein trajectory to predict colorectal anastomotic leak: PREDICT Study

BACKGROUND

Anastomotic leak is a common complication after colorectal surgery, associated with increased morbidity and mortality, and poorer long-term survival after oncological resections. Early diagnosis improves short-term outcomes, and may translate into reduced cancer recurrence. Multiple studies have attempted to identify biomarkers to enable earlier diagnosis of anastomotic leak. One study demonstrated that the trajectory of C-reactive protein (CRP) levels was highly predictive of anastomotic leak requiring intervention, with an area under the curve of 0·961. The aim of the present study was to validate this finding externally.

METHODS

This was a prospective international multicentre observational study of adults undergoing elective colorectal resection with an anastomosis. CRP levels were measured before operation and for 5 days afterwards, or until day of discharge if earlier than this. The primary outcome was anastomotic leak requiring operative or radiological intervention.

RESULTS

Between March 2017 and July 2018, 933 patients were recruited from 20 hospitals across Australia, New Zealand, England and Scotland. Some 833 patients had complete CRP data and were included in the primary analysis, of whom 41 (4·9 per cent) developed an anastomotic leak. A change in CRP level exceeding 50 mg/l between any two postoperative days had a sensitivity of 0·85 for detecting a leak, and a high negative predictive value of 0·99 for ruling it out. A change in CRP concentration of more than 50 mg/l between either days 3 and 4 or days 4 and 5 after surgery had a high specificity of 0·96-0·97, with positive likelihood ratios of 4·99-6·44 for a leak requiring intervention.

CONCLUSION

This study confirmed the value of CRP trajectory in accurately ruling out an anastomotic leak after colorectal resection.

Does postoperative inflammation or sepsis generate neutrophil extracellular traps that influence colorectal cancer progression? A systematic review

BACKGROUND

Colorectal cancer is the third most common cancer worldwide. Almost half of those that have a potentially curative resection go on to develop metastatic disease. A recognized risk for recurrence is perioperative systemic inflammation and sepsis. Neutrophil extracellular traps have been implicated as promotors of tumor progression. We aimed to examine the evidence in the literature for an association between neutrophil extracellular traps and postoperative metastasis in colorectal cancer.

MATERIALS AND METHODS

Studies published between 2000 and December 2018 that examined the role of neutrophil extracellular traps in sepsis and inflammation in colorectal cancer and in relation to tumor-related outcomes were identified through a database search of Cochrane, CINAHL, and MEDLINE. Quality and bias assessment was carried out by 2 reviewers.

RESULTS

Of 8,940 screened and of the 30 studies included, 21 were observational, 5 were in vivo experimental, 1 was in vitro, and 3 used a combination of these approaches.

CONCLUSION

There is clear evidence from the literature that presence of a preoperative systemic inflammatory response predicts cancer recurrence following potentially curative resection, but the evidence for association of sepsis and progression is lacking. There is robust experimental evidence in murine models showing that neutrophil extracellular traps are present in sepsis and are associated with cancer progression. Some human observational studies corroborate the prognostic significance of neutrophil extracellular traps in progression of colorectal cancer. Further human studies are needed to translate the experimental evidence and to definitively associate sepsis and neutrophil extracellular traps with poor colorectal cancer-specific outcomes.

Systematic Review on the Influence of Tissue Oxygenation on Gut Microbiota and Anastomotic Healing

BACKGROUND

Anastomotic leak rates have not improved over several decades despite improvements in surgical techniques and patient care. The gut microbiome has been implicated in the development of leaks. The exact mechanisms by which tissue oxygenation affects gut microbial composition and anastomotic healing physiology are unclear. Also, commonly used carbon dioxide (CO₂) is a known vasodilator that improves tissue oxygen tension. We performed a systematic review to determine the influence of hyperoxia, hypoxia, and hypercapnia on the gut microbiome and anastomotic healing.

METHODS

A literature search was performed in MEDLINE, EMBASE, and COCHRANE to identify studies investigating the effects of hyperoxia, hypoxia, and hypercapnia on anastomotic healing and gut microbiota published between 1998 and 2018. Two reviewers screened the articles for eligibility and quality. Fifty-three articles underwent full text review, and a narrative synthesis was undertaken.

RESULTS

Hyperoxia is associated with better anastomotic healing, increased gastrointestinal oxygen tension, and may reduce gut anaerobes. Hypoxia is associated with poor healing and increased gut anaerobes. However, it is unclear if hypoxia is the most important predictor of anastomotic leaks. Low pressure CO₂ pneumoperitoneum and mild systemic hypercapnia are both associated with increased gastrointestinal oxygen tension and may improve anastomotic healing. We found no studies which investigated the effect of hypercapnia on gut microbiota in the context of anastomotic healing.

CONCLUSIONS

Tissue oxygenation influences gut anastomotic healing, but little evidence exists to demonstrate the influence on the gut microbiome in the context of healing. Further studies are needed to determine if anastomotic microbiome changes with altered tissue oxygenation and if this affects healing and leak rates. If confirmed, altering tissue oxygenation through hyperoxia or hypercapnia could be feasible means of altering the microbiome such that anastomotic leak rates reduce.

Organic Contaminant Biodegradation by Oxidoreductase Enzymes in Wastewater Treatment

Organic contaminants (OCs), such as pharmaceuticals, personal care products, flame retardants, and plasticisers, are societally ubiquitous, environmentally hazardous, and structurally diverse chemical compounds whose recalcitrance to conventional wastewater treatment necessitates the development of more effective remedial alternatives. The engineered application of ligninolytic oxidoreductase fungal enzymes, principally white-rot laccase, lignin peroxidase, and manganese peroxidase, has been identified as a particularly promising approach for OC remediation due to their strong oxidative power, broad substrate specificity, low energy consumption, environmental benignity, and cultivability from lignocellulosic waste. By applying an understanding of the mechanisms by which substrate properties influence enzyme activity, a set of semi-quantitative physicochemical criteria (redox potential, hydrophobicity, steric bulk and pKa) was formulated, against which the oxidoreductase degradation susceptibility of twenty-five representative OCs was assessed. Ionisable, compact, and electron donating group (EDG) rich pharmaceuticals and antibiotics were judged the most susceptible, whilst hydrophilic, bulky, and electron withdrawing group (EWG) rich polyhalogenated compounds were judged the least susceptible. OC susceptibility scores were in general agreement with the removal rates reported for experimental oxidoreductase treatments (R2 = 0.60). Based on this fundamental knowledge, and recent developments in enzyme immobilisation techniques, microbiological enzymic treatment strategies are proposed to formulate a new generation of biological wastewater treatment processes for the biodegradation of environmentally challenging OC compounds.

Enzyme activity of waste activated sludge extracts

Wastewater treatment and generated biological sludge provide an alternative source of enzymes to conventional industrial production methods. Here, we present a protocol for extracting enzymes from activated sludge using ultrasonication and surfactant treatment. Under optimum conditions, ultrasound disruption of activated sludge gave recovery rates of protease and cellulase enzymes equivalent to 63.1% and ∼100%, respectively. The extracting of enzymes from activated sludge represents a potentially significant, high-value, resource recovery option for biological sludge generated by municipal wastewater treatment.

The LAPLAP study: a randomized placebo-controlled clinical trial assessing postoperative functional recovery using intraperitoneal local anaesthetic in laparoscopic colorectal surgery

AIM

Postoperative pain remains a major factor in recovery from colorectal resection. There is increasing interest in opioid-sparing analgesia, and intraperitoneal local anaesthetic (IPLA) has recently been shown to be useful in minor laparoscopic and open colorectal procedures. The aim of this study was to evaluate the impact of IPLA on functional recovery following major laparoscopic surgery. In this controlled trial, mobility, as measured by the De Morton Mobility Index (DEMMI), was used as a surrogate for postoperative functional recovery.

METHOD

Patients undergoing laparoscopic colorectal resection were randomized either to continuous ropivacaine (0.2% at 4-6 ml/h) or to saline (0.9%) which were administered via intraperitoneal catheter for 3 days postoperatively. Results were analysed in a double-blind manner. DEMMIs were assessed on postoperative days 1, 2, 3, 7 and 30, and data on pain, opioid consumption, gut and respiratory function, length of stay (LOS) and complications were recorded.

RESULTS

Ninety-six patients were recruited. There was no difference in primary outcome (i.e., functional recovery) between IPLA and placebo groups. Opioid consumption and LOS were similar between groups, and no differences were found for any secondary outcome measure. There were no adverse events related to ropivacaine.

CONCLUSION

Infusional intraperitoneal local anaesthetic appears to be safe but does not improve functional recovery or analgesic consumption following elective laparoscopic colorectal surgery, in the setting of an established enhanced recovery programme.

Albuminuria and Allograft Failure, Cardiovascular Disease Events, and All-Cause Death in Stable Kidney Transplant Recipients: A Cohort Analysis of the FAVORIT Trial

RATIONALE & OBJECTIVE

Cardiovascular disease (CVD) is common and overall graft survival is suboptimal among kidney transplant recipients. Although albuminuria is a known risk factor for adverse outcomes among persons with native chronic kidney disease, the relationship of albuminuria with cardiovascular and kidney outcomes in transplant recipients is uncertain.

STUDY DESIGN

Post hoc longitudinal cohort analysis of the Folic Acid for Vascular Outcomes Reduction in Transplantation (FAVORIT) Trial.

SETTING & PARTICIPANTS

Stable kidney transplant recipients with elevated homocysteine levels from 30 sites in the United States, Canada, and Brazil.

PREDICTOR

Urine albumin-creatinine ratio (ACR) at randomization.

OUTCOMES

Allograft failure, CVD, and all-cause death.

ANALYTICAL APPROACH

Multivariable Cox models adjusted for age; sex; race; randomized treatment allocation; country; systolic and diastolic blood pressure; history of CVD, diabetes, and hypertension; smoking; cholesterol; body mass index; estimated glomerular filtration rate (eGFR); donor type; transplant vintage; medications; and immunosuppression.

RESULTS

Among 3,511 participants with complete data, median ACR was 24 (Q1-Q3, 9-98) mg/g, mean eGFR was 49±18 (standard deviation) mL/min/1.73m², mean age was 52±9 years, and median graft vintage was 4.1 (Q1-Q3, 1.7-7.4) years. There were 1,017 (29%) with ACR < 10mg/g, 912 (26%) with ACR of 10 to 29mg/g, 1,134 (32%) with ACR of 30 to 299mg/g, and 448 (13%) with ACR ≥ 300mg/g. During approximately 4 years, 282 allograft failure events, 497 CVD events, and 407 deaths occurred. Event rates were higher at both lower eGFRs and higher ACR. ACR of 30 to 299 and ≥300mg/g relative to ACR < 10mg/g were independently associated with graft failure (HRs of 3.40 [95% CI, 2.19-5.30] and 9.96 [95% CI, 6.35-15.62], respectively), CVD events (HRs of 1.25 [95% CI, 0.96-1.61] and 1.55 [95% CI, 1.13-2.11], respectively), and all-cause death (HRs of 1.65 [95% CI, 1.23-2.21] and 2.07 [95% CI, 1.46-2.94], respectively).

LIMITATIONS

No data for rejection; single ACR assessment.

CONCLUSIONS

In a large population of stable kidney transplant recipients, elevated baseline ACR is independently associated with allograft failure, CVD, and death. Future studies are needed to evaluate whether reducing albuminuria improves these outcomes.

Heavy metal nephropathy: considerations for exposure analysis

Epidemiologic studies have yielded conflicting results regarding the role of heavy metal exposure in recent epidemics of chronic kidney disease (CKD). In this issue of Kidney International, Tsai et al. examined the combined effects of chromium, lead, and cadmium on kidney function using data from the Nutrition and Health Survey in Taiwan. We add this report to our growing understanding of contemporary epidemics of CKD and highlight considerations for exposure analysis in CKD epidemiologic studies.

Cryptosporidium parvum decay during air drying and stockpiling of mesophilic anaerobically digested sewage sludge in a simulation experiment and oocyst counts in sludge collected from operational treatment lagoons in Victoria, Australia

The inactivation of Cryptosporidium species oocysts during sewage sludge treatment is important to protect human health when the residual biosolids are applied to agricultural land. Quantifying the decay of Cryptosporidium species during sludge treatment for microbiological assurance purposes is difficult if low numbers are present in wastewater. The rate of decay of Cryptosporidium parvum oocysts during solar/air drying treatment and in sludge stockpiles in temperate environment conditions was simulated in laboratory inoculation experiments using sludge sampled from a mesophilic anaerobic digester. Oocyst numbers were also determined in settled lagoon sludge samples collected from three operational rural wastewater treatment plants (WWTPs). C. parvum oocysts were enumerated by immunomagnetic separation followed by staining with vital dyes and examination by confocal laser scanning microscopy. An air-drying/storage period equivalent to 11 weeks was required for a 1 log₁₀ reduction of viable oocysts inoculated into digested sludge. Oocyst viability in air-dried and stored digested sludge decreased with time, but was independent of sludge desiccation and dry solids (DS) content. No oocysts were detected in sludge samples collected from the anaerobic digester, and the average concentration of oocysts found in settled lagoon sludge from the rural WWTP was 4.6 × 10² oocysts/g DS.

Mobility scores as a predictor of length of stay in general surgery: a prospective cohort study

BACKGROUND

Post-operative length of stay (LOS) is an increasingly important clinical indicator in general surgery. Despite this, no tool has been validated to predict LOS or readiness for discharge in general surgical patients. The de Morton Mobility Index (DEMMI) is a functional mobility assessment tool that has been validated in rehabilitation patient populations. In this prospective cohort study, we aimed to identify if trends in DEMMI scores were associated with discharge within 1 week and overall LOS in general surgical patients.

METHODS

A total of 161 patients who underwent elective gastrointestinal resections were included. DEMMI scores were performed preoperatively, on days 1, 2, 3 and 30 post-operative. Statistical analysis was performed to identify any association between DEMMI scores and discharge within 1 week and LOS.

RESULTS

Functional recovery (measured by achieving 80% of baseline DEMMI score by post-operative day 1) was significantly associated with discharge within 1 week. Presence of a stoma was associated with longer LOS. The area under the receiver operating characteristic curve using functional recovery on post-operative day 1 as a predictor of discharge within 1 week is 0.772.

CONCLUSION

The DEMMI score is a fast, easy and useful tool to, on post-operative day 1, predict discharge within 1 week. The utility of this is to act as an anticipatory trigger for more proactive and efficient discharge planning in the early post-operative period, and there is potential to use the DEMMI as a comparator in clinical trials to assess functional recovery.

The Surgical Management of Pilonidal Disease is Uncertain Because of High Recurrence Rates

Background Pilonidal disease is a common condition with no consensus for the best management of chronic disease or current practice in Australia and New Zealand. Methods A survey was distributed among 190 colorectal and 592 general surgeons in Australia and New Zealand. Data was obtained regarding pilonidal surgery volume, procedures performed, non-operative management and recurrence rates. Three clinical scenarios were also presented. Results The response rate was 58% among colorectal surgeons, 18% among general surgeons. Nineteen percent of surgeons were high-volume (>23 operations per year), 47% low-volume (<12 operations per year). The commonest procedure was the Karydakis procedure (77%), with many others performed including rhomboid flaps (36%), Bascom cleft lift (13%), Z-plasty (7%), and gluteal rotation flaps (5%). Fifty-five percent of high-volume surgeons offered more than one operation while only 16% of low-volume surgeons did. Nineteen percent operated on all patients with pilonidal disease, 89% believing off-midline closure to be superior to midline. Disease extent was the main driver for non-operative management; patient factors such as cosmesis and time-off work being the least important. Sixty-four percent reported recurrence rates above 5%, and 37% recurrence rates >10%. Six percent reported no recurrences ever. Five percent reported recurrence rates over 20%, but 24% stated that over one-fifth of their practice consists of recurrent disease. Conclusions This study reports higher recurrence rates than in published series, suggesting many surgeons do not see their own recurrences, with current treatment not as successful as previously thought. Combined with the widespread variation in practice, optimal management of this disease remains unclear.

Uncontrolled burning of solid waste by households in Mexico is a significant contributor to climate change in the country

Uncontrolled burning of municipal solid waste (MSW) is an important source of air pollution and is wide spread in many developing countries, but only limited data quantify the extent of domestic open burning of household waste. Here, we present some of the first field data to be reported on the uncontrolled domestic burning of waste. A representative community of Mexico (Huejutla de Reyes Municipality) was investigated and household surveys, interviews with waste operators and a waste characterisation analysis were completed to assess the extent of, and factors controlling, the open burning of waste. Waste collection provision to rural communities was very limited and, consequently 92% of households in rural areas reported that they disposed of waste by uncontrolled burning in backyards or unofficial dumps. Overall, 24% of the total MSW generated in the Municipality was disposed by uncontrolled burning. Urban and periurban areas received twice-weekly collections and the rate of uncontrolled burning was considerably smaller compared to rural households, corresponding to approximately 2% of total waste generation. Carbon equivalency calculations showed that burning waste in backyards represented approximately 6% of the total and 8.5% of fuel related CO₂Eq emissions by the municipality. Moreover, the equivalent carbon dioxide (CO₂Eq) from black carbon (BC) emitted by uncontrolled burning in backyards was over fifteen times larger compared to methane (CH₄) potentially released from equivalent amounts of combustible biodegradable waste disposal at the official dumpsite. An assessment of local respiratory health data showed the incidence of disease was higher in rural than in urban areas, when the opposite trend is typically observed in the international literature; given the high rate of burning activity found in rural areas we suggest that open burning of waste could be a major reason for the apparent poorer respiratory health status of the rural population and requires further investigation. The results emphasise the importance of including BC from uncontrolled burning of waste in international emission inventories of greenhouse gases and in the assessment of the health status of local communities in developing countries where this practice is prevalent.

Manchester Arena bombing: lessons learnt from a mass casualty incident

On 22 May 2017 Salman Abedi detonated an improvised explosive device in the Manchester Arena resulting in 23 deaths (including the attacker). This was the deadliest terrorist attack on UK soil since the 2005 London bombings, but was only one of five mass casualty terrorist attacks in the UK in 2017. Preparation for mass casualty incidents (MCI) is obligatory, involving such methods as multiagency tabletop exercises, mock hospital exercises, as well as simulation and training for clinicians in managing the injuries that would be anticipated in such an event. Even in the best prepared units, such an incident will pose significant challenges due to the unpredictable nature of these events with respect to timing and number of casualties. Following an MCI, local and national reviews are undertaken to assess the effectiveness of the response, but also to identify areas where lessons can be learnt and to disseminate these to allow inclusion in future planning. We present the experience following a mass casualty terrorist incident along with a number of lessons learnt from this event.

Operator models for delivering municipal solid waste management services in developing countries. Part A: The evidence base

This article presents the evidence base for 'operator models' - that is, how to deliver a sustainable service through the interaction of the 'client', 'revenue collector' and 'operator' functions - for municipal solid waste management in emerging and developing countries. The companion article addresses a selection of locally appropriate operator models. The evidence shows that no 'standard' operator model is effective in all developing countries and circumstances. Each city uses a mix of different operator models; 134 cases showed on average 2.5 models per city, each applying to different elements of municipal solid waste management - that is, street sweeping, primary collection, secondary collection, transfer, recycling, resource recovery and disposal or a combination. Operator models were analysed in detail for 28 case studies; the article summarises evidence across all elements and in more detail for waste collection. Operators fall into three main groups: The public sector, formal private sector, and micro-service providers including micro-, community-based and informal enterprises. Micro-service providers emerge as a common group; they are effective in expanding primary collection service coverage into poor- or peri-urban neighbourhoods and in delivering recycling. Both public and private sector operators can deliver effective services in the appropriate situation; what matters more is a strong client organisation responsible for municipal solid waste management within the municipality, with stable political and financial backing and capacity to manage service delivery. Revenue collection is also integral to operator models: Generally the municipality pays the operator from direct charges and/or indirect taxes, rather than the operator collecting fees directly from the service user.

Verification of an alternative sludge treatment process for pathogen reduction at two wastewater treatment plants in Victoria, Australia

At South East Water wastewater treatment plants (WwTPs) in Victoria, Australia, biosolids are stockpiled for three years in compliance with the State guidelines to achieve the highest pathogen reduction grade (T1), suitable for unrestricted use in agriculture and landscaping. However, extended stockpiling is costly, may increase odour nuisance and greenhouse gas emissions, and reduces the fertiliser value of the biosolids. A verification programme of sampling and analysis for enteric pathogens was conducted at two WwTPs where sludge is treated by aerobic and anaerobic digestion, air drying (in drying pans or solar drying sheds) and stockpiling, to enumerate and, if present, monitor the decay of a range of enteric pathogens and parasites. The sludge treatment processes at both WwTPs achieved T1 grade biosolids with respect to prescribed pathogenic bacterial numbers (<1 Salmonella spp. 50 g^-1 dry solids (DS) and <100 Escherichia coli g^-1 DS) and >3 log₁₀ enteric virus reduction after a storage period of one year. No Ascaris eggs were detected in the influent to the WwTPs, confirming previous studies that the presence of helminth infections in Victoria is extremely low and that Ascaris is not applicable as a control criterion for the microbiological quality of biosolids in the region.

Serum Phosphorus and Risk of Cardiovascular Disease, All-Cause Mortality, or Graft Failure in Kidney Transplant Recipients: An Ancillary Study of the FAVORIT Trial Cohort

BACKGROUND

Mild hyperphosphatemia is a putative risk factor for cardiovascular disease [CVD], loss of kidney function, and mortality. Very limited data are available from sizable multicenter kidney transplant recipient (KTR) cohorts assessing the potential relationships between serum phosphorus levels and the development of CVD outcomes, transplant failure, or all-cause mortality.

STUDY DESIGN

Cohort study.

SETTING & PARTICIPANTS

The Folic Acid for Vascular Outcome Reduction in Transplantation (FAVORIT) Trial, a large, multicenter, multiethnic, controlled clinical trial that provided definitive evidence that high-dose vitamin B-based lowering of plasma homocysteine levels did not reduce CVD events, transplant failure, or total mortality in stable KTRs.

PREDICTOR

Serum phosphorus levels were determined in 3,138 FAVORIT trial participants at randomization.

RESULTS

During a median follow-up of 4.0 years, the cohort had 436 CVD events, 238 transplant failures, and 348 deaths. Proportional hazards modeling revealed that each 1-mg/dL higher serum phosphorus level was not associated with a significant increase in CVD risk (HR, 1.06; 95% CI, 0.92-1.22), but increased transplant failure (HR, 1.36; 95% CI, 1.15-1.62) and total mortality risk associations (HR, 1.21; 95% CI, 1.04-1.40) when adjusted for treatment allocation, traditional CVD risk factors, kidney measures, type of kidney transplant, transplant vintage, and use of calcineurin inhibitors, steroids, or lipid-lowering drugs. These associations were strengthened in models without kidney measures: CVD (HR, 1.14; 95% CI, 1.00-1.31), transplant failure (HR, 1.72; 95% CI, 1.46-2.01), and mortality (HR, 1.34; 95% CI, 1.15-1.54).

LIMITATIONS

We lacked data for concentrations of parathyroid hormone, fibroblast growth factor 23, or vitamin D metabolites.

CONCLUSIONS

Serum phosphorus level is marginally associated with CVD and more strongly associated with transplant failure and total mortality in long-term KTRs. A randomized controlled clinical trial in KTRs that assesses the potential impact of phosphorus-lowering therapy on these hard outcomes may be warranted.

Impact of avoiding post-operative urinary catheters on outcomes following colorectal resection in an ERAS programme: no IDUC and ERAS programmes

BACKGROUND

The presence of an indwelling urinary catheter (IDUC) is routine following colorectal resections. In Enhanced Recovery After Surgery programmes, excessive intravenous fluids (IVFs) are avoided. This study sought to determine whether the routine absence of an IDUC following colorectal surgery improved post-operative outcomes and minimized fluid prescription.

METHODS

A retrospective comparative cohort study was performed on patients undergoing colorectal resection at a tertiary referral teaching hospital, over a 7-year period. A policy of no routine IDUC was introduced over the last 3 years. Patients were divided into cohorts based on the presence or absence of an IDUC on leaving the operating theatre. The outcomes assessed were IVF prescription, length of stay, mortality and morbidity.

RESULTS

Of the 213 resections over the time period, 131 met the inclusion criteria (87 IDUC and 44 no IDUC). There was no difference between groups with respect to baseline demographics. Fluid administration was less in the group without routine IDUC (total fluid 6.16 L versus 10.89 L; P < 0.0001, fluid in the first 24 h 3.82 L versus 5.3 L; P < 0.0001 and fluid in the first 48 h 5.15 L versus 7.23 L; P < 0.0001). Length of stay was less in the 'no IDUC' group (5.9 days versus 10.1 days; P = 0.0009). There was no difference in morbidity and mortality.

CONCLUSION

A policy of no IDUC following colectomy was associated with a reduction in IVF administration and length of stay. A randomized controlled trial is recommended in order to more accurately determine the degree of causal relationship.

Biomarkers and anastomotic leakage in colorectal surgery: C-reactive protein trajectory is the gold standard

BACKGROUND

Anastomotic leakage is a feared complication following colorectal surgery. Early prediction results in improved clinical outcome, but accurate predictive factors remain elusive. Many biomarkers have been studied with respect to diagnosis of anastomotic leakage but the concept of trajectory testing, using biomarkers, has not been assessed with regards to early diagnosis of anastomotic leak.

METHODS

C-reactive protein (CRP), procalcitonin (PCT), white cell count (WCC) and gamma-glutamyl transferase were assessed for predictive utility in diagnosing anastomotic leakage with emphasis on identifying an association with change in their levels or trajectory. Levels were collected preoperatively and daily for the first 5 post-operative days on patients undergoing elective colorectal surgery, involving an anastomosis. Anastomotic leakage was defined clinically by operative or radiological intervention. Comparison was made between biomarkers and clinical anastomotic leakage, using receiver operator characteristic curves for logistic models, based on trajectory of the four biomarkers.

RESULTS

A total of 197 consecutive patients were analysed. Eleven patients developed clinical anastomotic leakage. An association of biomarker trajectory with anastomotic leakage was observed for WCC, PCT and CRP, but not for gamma-glutamyl transferase. CRP was the superior biomarker based on trajectory, with area under the receiver operator curve of 0.961.

CONCLUSION

This study identifies change in CRP, WCC and PCT as potential markers of anastomotic leakage following colorectal surgery and in particular highlights CRP trajectory as extremely accurate in diagnosing anastomotic leakage requiring intervention. External validation should be sought before incorporating this into routine clinical practice, given the numbers in this study.

Challenges and opportunities associated with waste management in India

India faces major environmental challenges associated with waste generation and inadequate waste collection, transport, treatment and disposal. Current systems in India cannot cope with the volumes of waste generated by an increasing urban population, and this impacts on the environment and public health. The challenges and barriers are significant, but so are the opportunities. This paper reports on an international seminar on 'Sustainable solid waste management for cities: opportunities in South Asian Association for Regional Cooperation (SAARC) countries' organized by the Council of Scientific and Industrial Research-National Environmental Engineering Research Institute and the Royal Society. A priority is to move from reliance on waste dumps that offer no environmental protection, to waste management systems that retain useful resources within the economy. Waste segregation at source and use of specialized waste processing facilities to separate recyclable materials has a key role. Disposal of residual waste after extraction of material resources needs engineered landfill sites and/or investment in waste-to-energy facilities. The potential for energy generation from landfill via methane extraction or thermal treatment is a major opportunity, but a key barrier is the shortage of qualified engineers and environmental professionals with the experience to deliver improved waste management systems in India.

Potential Modern Alternative Designs for Caries Clinical Trials (CCTs) and How These can be Validated against the Conventional Model

The main reasons that industry runs caries clinical trials (CCTs) are to provide proof of efficacy and to collect in vivo safety data on new products. In recent years, predominantly due to declining caries levels and the use of positive controls, the cost of performing these CCTs has escalated. It is now reaching the stage where it is becoming commercially prohibitive to conduct new studies. This is likely to stifle innovation of new anticaries products, and we now need new, more discriminatory, faster, and less expensive study designs. There are many ways in which the design of CCTs may be changed, such as improving diagnostic efficiency, improving data handling/statistical modeling, and using high-risk populations. However, it is paramount that the overriding principle behind CCT design validation must be that the results/conclusions from any new design are in line with those shown previously by ‘conventional’ CCTs, to ensure the maintenance of standards for both efficacy and safety. It is suggested that the validation of any new trial design must involve comparisons with regimens previously shown in conventional CCTs to have different anticaries efficacies. For example, since several clinical trials have shown convincing evidence for a monotonic dose response for fluoride at least up to levels of 2500 ppm F, one could choose two products, differing solely in their fluoride level. One aim for this workshop is to identify and agree on validation principles for new clinical trial designs. This will facilitate general international acceptance of novel smaller/faster CCTs designs both now and in the future. We recognize that any new design must not compromise the standard of proof of either efficacy or safety. In addition, any principles will need to take account of current understanding of the caries process, while recognizing the need for change to match future developments in cariology. Finally, the mechanism of action of the test product must be considered, in assessments of the acceptability of novel designs, if this differs markedly from the regimens used to validate the design.

The Challenges of Validating Diagnostic Methods Relative to a Conventional Two-year Caries Clinical Trial

This paper is directed to the question, “What are the appropriate validation criteria for the use of a new clinical trial methodology as a replacement for a conventional two- to three-year caries study?” It is important to recognize that the objective of a two- to three-year randomized, controlled caries trial is to test a precisely framed hypothesis, regarding an experimental product's efficacy relative to a control product. The external validity of conventional two- to three-year caries clinical studies in determining the efficacy and safety of anti-caries products is well-accepted. However, caries clinical trials are not without limitations and have increasingly been viewed as inefficient with respect to measuring the disease process in a holistic manner. The endpoint of a caries lesion with loss of enamel integrity (cavitation) focuses on one end of the caries progression continuum at the expense of early caries initiation and progression. Several early caries detection methods have been developed that correlate with mineral loss of the tooth surface. These diagnostics differ from conventional visual-tactile and radiographic methods in that they are capable of detecting early non-cavitated lesions, and this can generate continuous data. As diagnostic methods become accepted, they will lead to study designs that diverge from the conventional two- to three-year caries studies. Modification of the existing two- to three-year conventional caries design for assessment of product effectiveness, whether by the introduction of a new diagnostic method or by modification of the overall clinical design, must result in a clinical design that is able to differentiate known treatments on the basis of caries prevention efficacy. Given that the fluoride dose response has been characterized in the literature, this should form the basis of any validation package for new methodologies. In conclusion, a minimum expectation for acceptance as a replacement to conventional testing should be that the method or design can differentiate products of known efficacy from one another and that the efficacy relationship observed in a two- to three-year conventional study can be observed with the new method or design.

Population-based cohort study of variation in the use of emergency cholecystectomy for benign gallbladder diseases

Background

The aims of this prospective population-based cohort study were to identify the patient and hospital characteristics associated with emergency cholecystectomy, and the influences of these in determining variations between hospitals.

Methods

Data were collected for consecutive patients undergoing cholecystectomy in acute UK and Irish hospitals between 1 March and 1 May 2014. Potential explanatory variables influencing the performance of emergency cholecystectomy were analysed by means of multilevel, multivariable logistic regression modelling using a two-level hierarchical structure with patients (level 1) nested within hospitals (level 2).

Results

Data were collected on 4744 cholecystectomies from 165 hospitals. Increasing age, lower ASA fitness grade, biliary colic, the need for further imaging (magnetic retrograde cholangiopancreatography), endoscopic interventions (endoscopic retrograde cholangiopancreatography) and admission to a non-biliary centre significantly reduced the likelihood of an emergency cholecystectomy being performed. The multilevel model was used to calculate the probability of receiving an emergency cholecystectomy for a woman aged 40 years or over with an ASA grade of I or II and a BMI of at least 25·0 kg/m2, who presented with acute cholecystitis with an ultrasound scan showing a thick-walled gallbladder and a normal common bile duct. The mean predicted probability of receiving an emergency cholecystectomy was 0·52 (95 per cent c.i. 0·45 to 0·57). The predicted probabilities ranged from 0·02 to 0·95 across the 165 hospitals, demonstrating significant variation between hospitals.

Conclusion

Patients with similar characteristics presenting to different hospitals with acute gallbladder pathology do not receive comparable care.

Multicentre observational study of outcomes after drainage of acute perianal abscess

Introduction

Management of perianal abscesses has remained largely unchanged for over 50 years. The evidence for postoperative wound packing is limited and may expose patients to painful procedures with no clinical benefit and at considerable increased cost.

Methods

Patients were recruited in 15 UK centres between December 2013 and October 2014. Outcome measures included number of dressing (pack) changes, healing, recurrence, return to work/normal function, postoperative fistula in ano and health utility scores (EQ-5D™). Pain was measured before, during and after dressing change on a visual analogue scale.

Results

Some 141 patients were recruited (median age 39 (range 18–86) years). The mean number of dressing changes in the first 3 weeks was 13 (range 0–21), equating to an annual cost to the National Health Service of €6 453 360 in England alone per annum. Some 43·8 per cent of wounds were healed by 8 weeks after surgery and 86 per cent of patients had returned to normal function. Some 7·6 per cent of abscesses had recurred and 26·7 per cent of patients developed a fistula in ano by 6 months following surgery. Patients reported a twofold to threefold increase in pain scores during and after dressing changes.

Conclusion

Recurrent abscess is rare and fistula occurs in one-quarter of the patients. Packing is painful and costly.

A critical review of nitrogen mineralization in biosolids-amended soil, the associated fertilizer value for crop production and potential for emissions to the environment

International controls for biosolids application to agricultural land ensure the protection of human health and the environment, that it is performed in accordance with good agricultural practice and that nitrogen (N) inputs do not exceed crop requirements. Data from the scientific literature on the total, mineral and mineralizable N contents of biosolids applied to agricultural land under a wide range of climatic and experimental conditions were collated. The mean concentrations of total N (TN) in the dry solids (DS) of different biosolids types ranged from 1.5% (air-dried lime-treated (LT) biosolids) to 7.5% (liquid mesophilic anaerobic digestion (LMAD) biosolids). The overall mean values of mineralizable N, as a proportion of the organic N content, were 47% for aerobic digestion (AeD) biosolids, 40% for thermally dried (TD) biosolids, 34% for LT biosolids, 30% for mesophilic anaerobic digestion (MAD) biosolids, and 7% for composted (Com) biosolids. Biosolids air-dried or stored for extended periods had smaller total and mineralizable N values compared to mechanically dewatered types. For example, for biosolids treated by MAD, the mean TN (% DS) and mineralizable N (% organic N) contents of air-dried materials were 3% and 20%, respectively, compared to 5% and 30% with mechanical dewatering. Thus, mineralizable N declined with the extent of biological stabilization during sewage sludge treatment; nevertheless, overall plant available N (PAN=readily available inorganic N plus mineralizable N) was broadly consistent across several major biosolids categories within climatic regions. However, mineralizable N often varied significantly between climatic regions for similar biosolids types, influencing the overall PAN. This may be partly attributed to the increased rate, and also the greater extent of soil microbial mineralization of more stable, residual organic N fractions in biosolids applied to soil in warmer climatic zones, which also raised the overall PAN, compared to cooler temperate areas. It is also probably influenced by differences in upstream wastewater treatment processes that affect the balance of primary and secondary, biological sludges in the final combined sludge output from wastewater treatment, as well as the relative effectiveness of sludge stabilization treatments at specific sites. Better characterization of biosolids used in N release and mineralization investigations is therefore necessary to improve comparison of system conditions. Furthermore, the review suggested that some international fertilizer recommendations may underestimate mineralizable N in biosolids, and the N fertilizer value. Consequently, greater inputs of supplementary mineral fertilizer N may be supplied than are required for crop production, potentially increasing the risk of fertilizer N emissions to the environment. Thus greater economic and environmental savings in mineral N fertilizer application are potentially possible than are currently realized from biosolids recycling programmes.

Emergency General Surgery: evolution of a subspecialty by stealth

BACKGROUND

Emergency surgical patients account for around half of all NHS surgical workload and 80 % of surgical deaths. Few trainees opt to CCT in General Surgery, and there is no recognised subspecialty training program in Emergency General Surgery (EGS). Despite this lack of training and relevant assessment by examination, there appears to be an increasing number of EGS posts advertised. This study aims to provide information about potential future employment opportunities for surgical trainees.

METHODS

All consultant surgeon posts, advertised in the British Medical Journal between January 2009 and December 2014 were included. Data collected included specialty, region and institute of advertised post. For the purposes of statistical analysis, data was divided into two separate year bands: 2009-2011 and 2012-2014. Statistical analysis was by Chi-squared test; p <0.01 was considered statistically significant. An online tool was also used to determine experience and attitudes towards EGS amongst Consultant members of the ASGBI and all UK trainees in national training number (NTN) posts.

RESULTS

Over the six-year study period, there were 1240 consultant job adverts in a general surgical specialty. Nine hundred and 75 were substantive posts; the region with the most jobs was London and the South East (n = 278). There were 55 jobs advertised in EGS, either with (20) or without (35) another subspecialty. The number of EGS adverts increased significantly in 2012-14 compared to 2009-11 (p = 0.008). 229 (28 %) Consultants and 309 (22 %) trainees responded to the survey. 16 % of consultants work in NHS institutions with Emergency General Surgeons. Only 21 % of trainees believe EGS will be delivered by EGS consultants in the future whilst 8.2 % of trainees stated EGS as their career plan. Less than half of all UK consultant surgeons see EGS as a subspecialty.

CONCLUSIONS

This data demonstrates increasing societal need for EGS consultants over the last six years and the emergence of Emergency Surgery as a new subspecialty. In order to meet the EGS needs of the NHS, general surgical training and the examination system need to be revised.

Co-composting of invasive Acacia longifolia with pine bark for horticultural use

The feasibility of commercial-scale co-composting of waste biomass from the control of invasive Acacia species with pine bark waste from the lumber industry, in a blend ratio of 60:40 (v:v), was investigated and compared with previous research on the composting of Acacia without additional feedstock, to determine the potential process and end-product quality benefits of co-composting with bark. Pile temperatures rose rapidly to >70 °C and were maintained at >60 °C for several months. Acacia and bark biomass contained a large fraction of mineralizable organic matter (OM) equivalent to approximately 600 g kg(-1) of initial OM. Bark was more recalcitrant to biodegradation compared with Acacia, which degraded at twice the rate of bark. Therefore, incorporating the bark increased the final amount of compost produced compared with composting Acacia residues without bark. The relatively high C/N ratio of the composting matrix (C/N=56) and NH3 volatilization explained the limited increases in NH4+-N content, whereas concentrations of conservative nutrient elements (e.g. P, K, Ca, Mg, Fe) increased in proportion to OM mineralization, enriching the compost as a nutrient source for horticultural use. Nitrogen concentrations also increased to a small extent, but were much more dynamic and losses, probably associated with N volatilization mechanisms, were difficult to actively control. The physicochemical characteristics of the stabilized end-product, such as pH, electrical conductivity and OM content, were improved with the addition of bark to Acacia biomass, and the final compost characteristics were suitable for use for soil improvement and also as horticultural substrate components.

Factors affecting decay of Salmonella Birkenhead and coliphage MS2 during mesophilic anaerobic digestion and air drying of sewage sludge

Factors affecting the decay of Salmonella Birkenhead and coliphage, as representatives of bacterial and viral pathogens, respectively, during mesophilic anaerobic digestion (MAD) and air drying treatment of anaerobically digested sewage sludge were investigated. Controlled concentrations of S. Birkenhead were inoculated into non-sterile, autoclaved, γ-irradiated and nutrient-supplemented sludge and cultures were incubated at 37 °C (MAD sludge treatment temperature) or 20 °C (summer air drying sludge treatment temperature). Nutrient limitation caused by microbial competition was the principal mechanism responsible for the decay of S. Birkenhead by MAD and during air drying of digested sludge. The effects of protease activity in sludge on MS2 coliphage decay in digested and air dried sludge were also investigated. MS2 coliphage showed a 3.0-3.5 log10 reduction during incubation with sludge-protease extracts at 37 °C for 25 h. Proteases produced by indigenous microbes in sludge potentially increase coliphage inactivation and may therefore have a significant role in the decay of enteric viruses in sewage sludge. The results help to explain the loss of viability of enteric bacteria and viral pathogens with treatment process time and contribute to fundamental understanding of the various biotic inactivation mechanisms operating in sludge treatment processes at mesophilic and ambient temperatures.