To send content items to your account,
please confirm that you agree to abide by our usage policies.
If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account.
Find out more about sending content to .
To send content items to your Kindle, first ensure email@example.com
is added to your Approved Personal Document E-mail List under your Personal Document Settings
on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part
of your Kindle email address below.
Find out more about sending to your Kindle.
Note you can select to send to either the @free.kindle.com or @kindle.com variations.
‘@free.kindle.com’ emails are free but can only be sent to your device when it is connected to wi-fi.
‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
Surface sediments from a 160-km stretch of the River Clyde, Scotland, were analysed for persistent organic pollutants to investigate distribution, source and environmental effect. Glasgow's urban tributaries polyaromatic hydrocarbons (PAH) ranged from 2.3 to 4226mgkg–1, total petroleum hydrocarbons (TPH) 72 to 37879mgkg–1 and polychlorinated biphenyls (PCB) 3 to 809μgkg–1, which were more polluted than the upper River Clyde PAH that ranged from 0.1 to 42mgkg–1, TPH 3 to 260mgkg–1 and PCB 2 to 147μgkg–1. Intermediate values of the inner Clyde estuary PAH ranging from 0.6 to 30mgkg–1, and PCB ranging from 5 to 130μgkg–1, were attributed to point sources and sediment transfer from the urban tributaries. Comparison with sediment quality criteria suggested possible adverse effects on aquatic biota. PAH isomeric ratios confirmed a pyrolytic source throughout the Clyde and benzo[a]pyrene/benzo[g,h,i]perylene ratios >0.6 confirmed that upper, urban and estuarine domains all to a lesser or greater extent accumulated PAH from traffic emissions. The degree of chlorination determined from PCB homologues differed in each of the three domains, suggesting variable source or that the process aerobic/anaerobic degradation varied in each of the three domains. The anthropogenic impact of the city of Glasgow can be quantified in that the urban tributary sediment mean values were 60 (PAH), 33 (TPH) and 11 (PCB) times higher than the rural upper Clyde counterpart.
Surface sediments (n=85) from a 160-km river-estuarine transect of the Clyde, UK, were analysed for total mercury (Hg), saturated hydrocarbons and unresolved complex mixtures (UCMs) of hydrocarbons. Results show that sediment-Hg concentration ranges from 0.01 to 1.38mgkg–1 (mean 0.20mgkg–1) and a spatial trend in Hg-content low–high–low–high, from freshwater source, to Glasgow, to estuary, is evident. In summary, sediment-Hg content is low in the upper Clyde (mean of 0.05Hg mgkg–1), whereas sediments from the Clyde in urbanised Glasgow have higher Hg concentrations (0.04 to 1.26mgkg–1; mean 0.45mgkg–1), and the inner estuary sediments contain less Hg (mean 0.06mgkg–1). The highest mean sediment Hg (0.65mgkg–1) found in the outer estuary is attributed to historical anthropogenic activities. A significant positive Spearman correlation between Hg and total organic carbon is observed throughout the river estuary (0.86; P<0.001). Comparison with Marine Scotland guidelines suggests that no sites exceed the 1.5mgkg–1 criterion (Action Level 2); 22 fall between 0.25 and 1.5mgkg–1 dry wt. (Action Level 1) and 63 are of no immediate concern (<0.25mgkg–1 dry wt.). Saturated (n-alkane) hydrocarbons in the upper Clyde are of natural terrestrial origin. By contrast, the urbanised Glasgow reaches and outer estuary are characterised by pronounced and potentially toxic UCM concentrations in sediments (380–914mg/kg and 103–247mgkg–1, respectively), suggesting anthropogenic inputs such as biodegraded crude oil, sewage discharge and/or urban run-off.
To determine the prevalence of Clostridium difficile colonization among patients who meet the 2017 IDSA/SHEA C. difficile infection (CDI) Clinical Guideline Update criteria for the preferred patient population for C. difficile testing.
Tertiary-care hospital in St. Louis, Missouri.
Patients whose diarrheal stool samples were submitted to the hospital’s clinical microbiology laboratory for C. difficile testing (toxin EIA) from August 2014 to September 2016.
Electronic and manual chart review were used to determine whether patients tested for C. difficile toxin had clinically significant diarrhea and/or any alternate cause for diarrhea. Toxigenic C. difficile culture was performed on all stool specimens from patients with clinically significant diarrhea and no known alternate cause for their diarrhea.
A total of 8,931 patients with stool specimens submitted were evaluated: 570 stool specimens were EIA positive (+) and 8,361 stool specimens were EIA negative (−). Among the EIA+stool specimens, 107 (19% of total) were deemed eligible for culture. Among the EIA− stool specimens, 515 (6%) were eligible for culture. One EIA+stool specimen (1%) was toxigenic culture negative. Among the EIA− stool specimens that underwent culture, toxigenic C. difficile was isolated from 63 (12%).
Most patients tested for C. difficile do not have clinically significant diarrhea and/or potential alternate causes for diarrhea. The prevalence of toxigenic C. difficile colonization among EIA− patients who met the IDSA/SHEA CDI guideline criteria for preferred patient population for C. difficile testing was 12%.
European swallowwort [Vincetoxicum rossicum (Kleopow) Barbarich] is found in the northeastern United States and southeastern Canada. It forms dense growth patterns that reduce plant and insect biodiversity, and lab assays show that it produces allelopathic compounds that affect microbial activity. Consequently, we hypothesized that V. rossicum alters soil microbiome composition and activity in invaded habitats, which may impact ecosystem properties and processes. We sampled soil from a similar time point within a growing season at each of five sites in New York State where V. rossicum was both present and absent. We measured bacterial and fungal microbiome composition, available soil nitrogen (N), soil respiration (CO2 flux), and soil extracellular enzyme activities. Microbial composition varied across field sites, but only fungal composition was affected by invasion. No significant differences were found between the invaded and uninvaded plots at any of the sites for available soil ammonium, nitrate, or respiration, though extractable N varied greatly between sites. Microbial hydrolytic extracellular enzyme activities suggest decreased protein degradation and increased oxidative enzyme activity with V. rossicum invasion, which is relevant to soil N and carbon cycling processes. Although V. rossicum impacted rhizosphere microbial composition and activity, it was not associated with large perturbations in ecosystem function when examined across multiple invasion sites during this short-term study.
To determine incidence of and risk factors for readmissions with multidrug-resistant organism (MDRO) infections among patients with previous MDRO infection.
Retrospective cohort of patients admitted between January 1, 2006, and October 1, 2015.
Barnes-Jewish Hospital, a 1,250-bed academic tertiary referral center in St Louis, Missouri.
We identified patients with MDROs obtained from the bloodstream, bronchoalveolar lavage (BAL)/bronchial wash, or other sterile sites. Centers for Disease Control and prevention (CDC) and European CDC definitions of MDROs were utilized. All readmissions ≤1 year from discharge from the index MDRO hospitalization were evaluated for bloodstream, BAL/bronchial wash, or other sterile site cultures positive for the same or different MDROs.
In total, 4,429 unique patients had a positive culture for an MDRO; 3,453 of these (78.0%) survived the index hospitalization. Moreover, 2,127 patients (61.6%) were readmitted ≥1 time within a year, for a total of 5,849 readmissions. Furthermore, 512 patients (24.1%) had the same or a different MDRO isolated from blood, BAL/bronchial wash, or another sterile site during a readmission. Bone marrow transplant, end-stage renal disease, lymphoma, methicillin-resistant Staphylococcus aureus, or carbapenem-resistant Pseudomonas aeruginosa during index hospitalization were factors associated with increased risk of having an MDRO isolated during a readmission. MDROs isolated during readmissions were in the same class of MDRO as the index hospitalization 9%–78% of the time, with variation by index pathogen.
Readmissions among patients with MDRO infections are frequent. Various patient and organism factors predispose to readmission. When readmitted patients had an MDRO, it was often a pathogen in the same class as that isolated during the index admission, with the exception of Acinetobacter (~9%).
To evaluate healthcare worker (HCW) risk of self-contamination when donning and doffing personal protective equipment (PPE) using fluorescence and MS2 bacteriophage.
Prospective pilot study.
A total of 36 HCWs were included in this study: 18 donned/doffed contact precaution (CP) PPE and 18 donned/doffed Ebola virus disease (EVD) PPE.
HCWs donned PPE according to standard protocols. Fluorescent liquid and MS2 bacteriophage were applied to HCWs. HCWs then doffed their PPE. After doffing, HCWs were scanned for fluorescence and swabbed for MS2. MS2 detection was performed using reverse transcriptase PCR. The donning and doffing processes were videotaped, and protocol deviations were recorded.
Overall, 27% of EVD PPE HCWs and 50% of CP PPE HCWs made ≥1 protocol deviation while donning, and 100% of EVD PPE HCWs and 67% of CP PPE HCWs made ≥1 protocol deviation while doffing (P=.02). The median number of doffing protocol deviations among EVD PPE HCWs was 4, versus 1 among CP PPE HCWs. Also, 15 EVD PPE protocol deviations were committed by doffing assistants and/or trained observers. Fluorescence was detected on 8 EVD PPE HCWs (44%) and 5 CP PPE HCWs (28%), most commonly on hands. MS2 was recovered from 2 EVD PPE HCWs (11%) and 3 CP PPE HCWs (17%).
Protocol deviations were common during both EVD and CP PPE doffing, and some deviations during EVD PPE doffing were committed by the HCW doffing assistant and/or the trained observer. Self-contamination was common. PPE donning/doffing are complex and deserve additional study.
To determine whether Clostridium difficile is present in the food of hospitalized patients and to estimate the risk of subsequent colonization associated with C. difficile in food.
This was a prospective cohort study of inpatients at a university-affiliated tertiary care center, May 9, 2011–July 12, 2012. Enrolled patients submitted a portion of food from each meal. Patient stool specimens and/or rectal swabs were collected at enrollment, every 3 days thereafter, and at discharge, and were cultured for C. difficile. Clinical data were reviewed for evidence of infection due to C. difficile. A stochastic, discrete event model was developed to predict exposure to C. difficile from food, and the estimated number of new colonization events from food exposures per 1,000 admissions was determined.
A total of 149 patients were enrolled and 910 food specimens were obtained. Two food specimens from 2 patients were positive for C. difficile (0.2% of food samples; 1.3% of patients). Neither of the 2 patients was colonized at baseline with C. difficile. Discharge colonization status was available for 1 of the 2 patients and was negative. Neither was diagnosed with C. difficile infection while hospitalized or during the year before or after study enrollment. Stochastic modeling indicated contaminated hospital food would be responsible for less than 1 newly colonized patient per 1,000 hospital admissions.
The recovery of C. difficile from the food of hospitalized patients was rare. Modeling suggests hospital food is unlikely to be a source of C. difficile acquisition.
Recent archaeological investigations at Pueblo Bonito in Chaco Canyon reveal that residents constructed a large diversion channel during the eleventh century A.D. as dramatic growth resulted in the expansion of the building onto the main valley floor. Sediments in the diversion channel reflect repeated episodes of flooding, rather than slow moving water typically found in irrigation canals, and archaeobotanical data indicate deposition during late summer or early fall. Although an agricultural function is possible, the channel may have been built primarily to divert floodwaters away from Pueblo Bonito while providing a nearby water source for construction and domestic use. The diversion channel was destroyed by the entrenchment of the “Bonito paleo-channel” in the late A.D. 1000s, and then buried by a combination of cultural debris and valley flooding. Although the canyon stream system changed throughout the occupation of Pueblo Bonito, there is no evidence that the formation of a deep natural channel in the floodplain had any negative effect on the growth of the great house
Wood ants play an ecologically dominant and conspicuous role in temperate boreal forests, making a keystone contribution to woodland ecosystem functions and processes. Wood ant taxonomy and global distributions set the scene for this text's exploration of wood ants as social insects, examining their flexible social structures, genetics, population ecology, and behaviour, from nest-mate recognition to task allocation. Wood ants' interactions with their environment and with other organisms are essential to their success: competition, predation and mutualism are described and analysed. Bringing together the expertise of ecological researchers and conservation practitioners, this book provides practical and theoretical advice about sampling and monitoring these insects, and outlines the requirements for effective conservation. This is an indispensable resource for wood ant researchers, entomologists, conservationists and ecological consultants, as well as anyone interested in social insects, keystone species and the management and conservation of forest ecosystems.
This was a randomized controlled pilot study of Lactobacillus rhamnosus GG versus standard of care to prevent gastrointestinal multidrug-resistant organism colonization in intensive care unit patients. Among 70 subjects, there were no significant differences in acquisition or loss of any multidrug-resistant organisms (P>.05) and no probiotic-associated adverse events.
Infect. Control Hosp. Epidemiol. 2015;36(12):1451–1454
There is evidence to suggest that social skills, such as the ability to understand the perspective of others (theory of mind), may be affected by childhood traumatic brain injuries; however, studies to date have only considered moderate and severe traumatic brain injury (TBI). This study aimed to assess theory of mind after early, mild TBI (mTBI). Fifty-one children who sustained mTBI between 18 and 60 months were evaluated 6 months post-injury on emotion and desires reasoning and false-belief understanding tasks. Their results were compared to that of 50 typically developing children. The two groups did not differ on baseline characteristics, except for pre- and post-injury externalizing behavior. The mTBI group obtained poorer scores relative to controls on both the emotion and desires task and the false-belief understanding task, even after controlling for pre-injury externalizing behavior. No correlations were found between TBI injury characteristics and theory of mind. This is the first evidence that mTBI in preschool children is associated with theory of mind difficulties. Reduced perspective taking abilities could be linked with the social impairments that have been shown to arise following TBI. (JINS, 2015, 21, 483–493)