Survival of Clostridioides difficile spores in thermal and chemo-thermal laundering processes and influence of the exosporium on their adherence to cotton bed sheets.

Clostridioides difficile spores were previously demonstrated to survive industrial laundering. Understanding interactions between heat, disinfectants and soiling (e.g. bodily fluids) affecting C. difficile spore survival could inform the optimization of healthcare laundry processes. Reducing spore attachment to linen could also enhance laundering efficacy. This study aimed to compare the sensitivity of C. difficile spores to heat and detergent, with and without soiling and to investigate adherence to cotton. Survival of C. difficile spores exposed to industrial laundering temperatures (71-90°C), reference detergent and industrial detergent was quantified with and without soiling. The adherence to cotton after 0 and 24 h air drying was determined with the exosporium of C. difficile spores partially or fully removed. Clostridioides difficile spores were stable at 71°C for 20 min (≤0·37 log10 reduction) while 90°C was sporicidal (3 log10 reduction); soiling exerted a protective effect. Industrial detergent was more effective at 71°C compared to 25°C (2·81 vs 0·84 log10 reductions), however, specifications for sporicidal activity (>3 log10 reduction) were not met. Clostridioides difficile spores increasingly adhered to cotton over time, with 49% adherence after 24 h. Removal of the exosporium increased adherence by 19-23% compared to untreated spores. Further understanding of the role of the exosporium in attachment to cotton could enhance spore removal and aid decontamination of linen.

Microemulsification of essential oils for the development of antimicrobial and mosquito repellent functional coatings for textiles.

AIMS: To develop an essential oil (EO)-loaded textile coating using an environmentally friendly microemulsion technique to achieve both antimicrobial and mosquito repellent functionalities. METHODS AND RESULTS: Minimum inhibitory concentrations and fractional inhibitory concentrations of litsea, lemon and rosemary EOs were determined against Staphylococcus aureus, Escherichia coli, Staphylococcus epidermidis, Pseudomonas aeruginosa and Trichophyton rubrum. A 1 : 2 mixture of litsea and lemon EOs inhibited all the microorganisms tested and was incorporated into a chitosan-sodium alginate assembly by a microemulsification process. The EO-loaded microemulsions were applied to cotton and polyester fabrics using a soak-pad-dry method. The textile challenge tests demonstrated 7-8 log10 reductions of S. epidermidis, S. aureus and E. coli after 24 h and T. rubrum after 48 h. Aedes aegypti mosquito repellency was also assessed which demonstrated 71·43% repellency compared to 52·94% by neat EO-impregnated cotton. CONCLUSIONS: Textiles treated with the litsea and lemon EO microemulsion showed strong antimicrobial activity against the skin associated microorganisms E. coli, S. aureus, S. epidermidis and T. rubrum and potential mosquito repellent properties. SIGNIFICANCE AND IMPACT OF THE STUDY: EOs could be useful for the development of natural, environmentally friendly functional textiles to protect textiles and users from microbial contamination in addition to possessing other beneficial properties such as mosquito repellency.

The effect of climbing chalk powder on the infectivity of human coronavirus OC43.

There does not appear to be any studies in the published literature on the stability of SARS-CoV-2 in climbing chalk powder (magnesium carbonate and/or calcium carbonate), which has been hypothesized to pose a potential risk of fomite transmission of coronavirus disease 2019 (COVID-19) within climbing gyms. The aim of this study was to determine the infectivity of a model human coronavirus HCoV-OC43 in the presence of climbing chalk powder on a dry plastic surface. The stability of HCoV-OC43 on a plastic surface dusted with climbing chalk powders (magnesium carbonate, calcium carbonate or a blended chalk) was determined by titration on BHK-21 fibroblast cells. No chalk and no virus controls were included. HCoV-OC43 was stable on the plastic surface for 48 h. The stability of HCoV-OC43 was significantly (P ≤ 0·05) reduced in the presence of magnesium carbonate, calcium carbonate and the chalk blend; the infectivity was reduced by ≥2·29 log10 50% tissue culture infective dose (TCID50 ) immediately upon on contact and by ≥2·46 log10 TCID50 within 1 h of contact. These findings suggest that the infectivity of coronaviruses is reduced by climbing chalk, limiting the risk of potential fomite transmission.

Development of a silver-based dual-function antimicrobial laundry additive and textile coating for the decontamination of healthcare laundry.

AIMS: To repurpose a silver-based antimicrobial textile coating product (Micro-Fresh 1911) as a dual-function antimicrobial laundry additive and textile coating. METHODS AND RESULTS: Survival of Escherichia coli or Staphylococcus aureus type and clinical isolates in a domestic 40°C wash was assessed with and without soiling and biological detergent. Washing with 2% w/v silver additive (wash phase) reduced E. coli and S. aureus by 7·14-8·08 log10 and no cross-contamination was observed. Under dirty conditions, 0·5% silver additive in the rinse phase of a wash with biological detergent reduced E. coli and S. aureus by 7·98-8·40 log10 (0·00-1·42 log10 cross contamination). BS EN ISO 20645:2004 and BS EN ISO 20743:2013 methods were used to assess the antimicrobial activity of polycotton washed with 2% w/v silver additive against S. aureus and E. coli. The treated polycotton was antimicrobial against E. coli and S. aureus type and clinical isolates and remains active after at least one further wash cycle at 40 or 73°C. CONCLUSIONS: The silver additive exhibits antimicrobial activity in a 40°C domestic wash, preventing cross contamination onto clean textiles and depositing an antimicrobial coating onto polycotton. SIGNIFICANCE AND IMPACT OF THE STUDY: The survival of micro-organisms on healthcare uniforms during domestic laundering presents a potential risk of contaminating the home, cross-contamination of other clothing within the wash and transmitting potential pathogens back into healthcare settings via contaminated uniforms. Silver may be useful as an antimicrobial laundry additive to decontaminate healthcare laundry washed at low temperatures in domestic and industrial settings, to therefore reduce the potential risk of transmitting micro-organisms within the domestic and clinical environments.

The effect of low-temperature laundering and detergents on the survival of Escherichia coli and Staphylococcus aureus on textiles used in healthcare uniforms.

AIMS: To determine the survival of Escherichia coli and Staphylococcus aureus on cotton and polyester and the effectiveness of low-temperature laundering and detergents on the removal of micro-organism from healthcare laundry. METHODS AND RESULTS: Survival of E. coli and S. aureus on polyester or cotton was assessed over 3 weeks and the efficacy of a domestic wash (40 and 60°C) and a range of detergents was also determined. Both bacteria were able to survive on cotton (5 log(10) ) and polyester (0·28 log(10) ) for up to 3 weeks. Laundering at 40°C resulted in a 3·5 log(10) removal of the initial 7·7 log(10) inoculum and some cross-contamination to sterile fabrics (3 log(10) ). Increasing the temperature to 60°C resulted in the complete removal of the initial inoculum. CONCLUSIONS: This study shows that most of the micro-organisms are removed at 40°C, however, those cells still remaining may have the potential for further contamination to the clinical environment and patients. SIGNIFICANCE AND IMPACT OF THE STUDY: National Health Service (NHS) nurses are required to domestically launder their uniforms at 60°C to ensure safe removal of micro-organisms, 33% of NHS staff questioned said they launder their uniforms at 40°C, which could potentially result in transmission of hospital-acquired infections.

U2AF1 mutations alter sequence specificity of pre-mRNA binding and splicing.

We previously identified missense mutations in the U2AF1 splicing factor affecting codons S34 (S34F and S34Y) or Q157 (Q157R and Q157P) in 11% of the patients with de novo myelodysplastic syndrome (MDS). Although the role of U2AF1 as an accessory factor in the U2 snRNP is well established, it is not yet clear how these mutations affect splicing or contribute to MDS pathophysiology. We analyzed splice junctions in RNA-seq data generated from transfected CD34+ hematopoietic cells and found significant differences in the abundance of known and novel junctions in samples expressing mutant U2AF1 (S34F). For selected transcripts, splicing alterations detected by RNA-seq were confirmed by analysis of primary de novo MDS patient samples. These effects were not due to impaired U2AF1 (S34F) localization as it co-localized normally with U2AF2 within nuclear speckles. We further found evidence in the RNA-seq data for decreased affinity of U2AF1 (S34F) for uridine (relative to cytidine) at the e-3 position immediately upstream of the splice acceptor site and corroborated this finding using affinity-binding assays. These data suggest that the S34F mutation alters U2AF1 function in the context of specific RNA sequences, leading to aberrant alternative splicing of target genes, some of which may be relevant for MDS pathogenesis.

Vapour phase: a potential future use for essential oils as antimicrobials?

Essential oil (EO) vapours have been known for their antimicrobial properties since the 4th century B.C.; however, it was not until the early 1960s that research into the potential of these volatile oils was explored. More recently, the use of EOs such as tea tree, bergamot, lavender and eucalyptus in vapour form has been shown to have antimicrobial effects against both bacteria and fungi, with range of methods being developed for dispersal and efficacy testing. To date, many applications for EO vapours as antimicrobials have been identified including in the food and clinical arenas.

Reduction of surface contamination and biofilms of Enterococcus sp. and Staphylococcus aureus using a citrus-based vapour.

BACKGROUND: Antibiotic-resistant organisms such as meticillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus sp. (VRE) are an ongoing problem in hospitals. Essential oil vapours (EOs) have been shown to reduce environmental bacterial contamination. AIMS: To assess the efficacy of Citri-V™, a vaporized blend of citrus EOs (orange: bergamot, 1:1 v/v) (Belmay, Northampton, UK), at removing Enterococcus sp. and S. aureus from stainless steel surfaces; and to investigate its effect on the formation of bacterial biofilms. METHODS: A microplate assay was used to assess the effect of the citrus vapour on the formation of biofilms and their metabolic activity. Biofilm removal from stainless steel surfaces was measured by a colorimetric assay and by digital microscopy. FINDINGS: The citrus vapour reduced VRE and MRSA on stainless steel surfaces by 1.5-3log(10) after 24h exposure. Staphylococcal biofilms were reduced both during and after formation, whereas enterococcal biofilms were significantly reduced (P≤0.05) only after formation. Metabolic activity decreased by up to 72% in strains tested. Two-dimensional digital microscopy showed reductions in biofilm coverage of the stainless steel disc by as much as 99.5%. CONCLUSION: Citrus vapour has potential for application in the clinical environment, for instance as a secondary disinfectant to reduce surface contamination by VRE and MRSA.

Evaluating the link between the management of clinical waste in the National Health Service (NHS) and the risk of the spread of infections: A case study of three hospitals in England.

This study aimed to evaluate waste management practices in three case study NHS Trusts in England and the potential risks of the spread of pathogens causing healthcare associated infections (HCAIs). Using a combination of microbiological techniques, interviews and questionnaire surveys, four target microbes were studied, namely: meticillin resistant Staphylococcus aureus (MRSA), meticillin sensitive Staphylococcus aureus (MSSA), Clostridium difficile (C. difficile) and vancomycin-resistant enterococci (VRE). Waste Flow Diagrams (WFDs) were used to map the flow of the waste. While there was a perceived link between the management of the waste and the spread of the microbes by staff, none of the target organisms were isolated. The findings suggest that when the waste is properly contained and managed that it should not pose a significant risk in terms of the spread of the four bacteria tested in this study. In addition, the results demonstrate that there is a need for staff perceptions and beliefs to be addressed in the development of policies and training related to infection control and its link to waste management.

Rainfall and drought in equatorial east Africa during the past 1,100 years.

Knowledge of natural long-term rainfall variability is essential for water-resource and land-use management in sub-humid regions of the world. In tropical Africa, data relevant to determining this variability are scarce because of the lack of long instrumental climate records and the limited potential of standard high-resolution proxy records such as tree rings and ice cores. Here we present a decade-scale reconstruction of rainfall and drought in equatorial east Africa over the past 1,100 years, based on lake-level and salinity fluctuations of Lake Naivasha (Kenya) inferred from three different palaeolimnological proxies: sediment stratigraphy and the species compositions of fossil diatom and midge assemblages. Our data indicate that, over the past millennium, equatorial east Africa has alternated between contrasting climate conditions, with significantly drier climate than today during the 'Medieval Warm Period' (approximately AD 1000-1270) and a relatively wet climate during the 'Little Ice Age' (approximately AD 1270-1850) which was interrupted by three prolonged dry episodes. We also find strong chronological links between the reconstructed history of natural long-term rainfall variation and the pre-colonial cultural history of east Africa, highlighting the importance of a detailed knowledge of natural long-term rainfall fluctuations for sustainable socio-economic development.

Behavior and physiology of social stress and depression in female cynomolgus monkeys.

The hypothesis that social subordination is stressful, and results in a depressive response in some individuals, was examined in socially housed female cynomolgus monkeys. Social status was manipulated such that half of the previously subordinate females became dominant and half of the previously dominant females became subordinate. Current subordinates hypersecreted cortisol, were insensitive to negative feedback, and had suppressed reproductive function. Current subordinates received more aggression, engaged in less affiliation, and spent more time alone than dominants. Furthermore, they spent more time fearfully scanning the social environment and displayed more behavioral depression than dominants. Current subordinates with a history of social subordination were preferentially susceptible to a behavioral depression response. The results of this experiment suggest that the stress of social subordination causes hypothalamic-pituitary-adrenal and ovarian dysfunction, and support the hypothesis that chronic, low-intensity social stress may result in depression in susceptible individuals.

Effects of isoflurane anesthesia on glucose tolerance and insulin secretion in Yucatan minipigs.

Isoflurane's effect on intravenous glucose tolerance and insulin secretion was studied in six Yucatan minipigs. Unanesthetized animals, with previously placed indwelling venous catheters, were tested while resting comfortably in slings. The same animals were then retested during isoflurane anesthesia. Serum glucose and insulin concentrations were measured at predetermined times in response to an intravenous bolus of dextrose. The glucose disappearance rate (k), baseline plasma insulin concentration, the area under the insulin response curve, and the insulinogenic index were significantly lower in the anesthetized animals than in controls. The results of this study indicate that anesthesia with isoflurane significantly alters the glucose/insulin response to an intravenous glucose tolerance test and, therefore, is unsuitable for studies when glucose tolerance is to be assessed.

Assessment of abdominal fat deposition in female cynomolgus monkeys.

Computed tomography (CT) was used to assess abdominal fat distribution in adult, female cynomolgus macaques (Macaca fascicularis). The technique used was similar to that applied in human beings and allowed intra-abdominal, subcutaneous and total abdominal fat to be quantitated in 1 cm thick sections. Correlations between single scans and the average of scans at several levels ranged from r = 0.96 to r = 1.00, indicating that a single scan is representative of abdominal fat distribution. Significant positive correlations were found between body mass index (BMI) and intra-abdominal fat (r = 0.89), subcutaneous fat (r = 0.91) and total abdominal fat (r = 0.90). As BMI increased, fat was preferentially deposited subcutaneously versus intra-abdominally. A unique fat depot, not previously described, was identified dorso-laterally between the internal abdominal oblique and the transversalis muscle. This fat depot was also positively correlated with BMI (r = 0.79). These results indicate that CT can be used in cynomolgus monkeys to quantitate regional fat deposits and that these monkeys resemble human beings in their abdominal fat patterning.

T-cell lymphosarcoma in a female African green monkey (Cercopithecus aethiops).

A female African green monkey developed a generalized lymphosarcoma spontaneously that clinically and pathologically resembled malignant lymphoma in human beings infected with human T-lymphotropic virus type I. The monkey was serologically positive for simian T-lymphotropic virus. Immunocytochemical analysis of routinely fixed and paraffin embedded tumor tissue demonstrated neoplastic cells that stained positive with antihuman monoclonal UCHL1 which recognized a T-cell-restricted isotype of leukocyte common antigen.

Fatal fatty liver-kidney syndrome in obese monkeys.

A fatal syndrome associated with brief periods of anorexia or acute weight loss was noted in monkeys. Affected monkeys died unexpectedly or after a very short illness. Consistent gross findings at necropsy were enlarged, pale yellow livers, pale tan to yellow kidneys, abundant deposits of body fat and empty gastrointestinal tracts. Fatty change of the liver and kidney was the predominant and characteristic lesion found microscopically. Most of the monkeys were female Macaca fascicularis greater than 8 years of age. However, monkeys of other species and ages, and one male also died of this syndrome. Affected monkeys generally had losses of 8-33% of body weight (last measured weight--weight at death). In some animals, this syndrome was associated with a location change forcing new social interactions. A common clinical pathologic finding was azotemia. These findings suggest that obese monkeys may be prone to a fatal syndrome characterized by fatty change of the liver and kidney, and weight loss.