Enhanced survival but not amplification of Francisella spp. in the presence of free-living amoebae

Transmission of Francisella tularensis, the etiologic agent of tularemia, has been associated with various water sources. Survival of many waterborne pathogens within free-living amoeba (FLA) is well documented; however, the role of amoebae in the environmental persistence of F. tularensis is unclear. In this study, axenic FLA cultures of Acanthamoeba castellanii, Acanthamoeba polyphaga, and Vermamoeba vermiformis were each inoculated with virulent strains of F. tularensis (Types A and B), the attenuated live vaccine strain, and Francisella novicida. Experimental parameters included low and high multiplicity of infection and incubation temperatures of 25 and 30 °C for 0–10 days. Francisella spp. survival was enhanced by the presence of FLA; however, bacterial growth and protozoa infectivity were not observed. In contrast, co-infections of A. polyphaga and Legionella pneumophila, used as an amoeba pathogen control, resulted in bacterial proliferation, cytopathic effects, and amoebal lysis. Collectively, even though short-term incubation with FLA was beneficial, the long-term effects on Francisella survival are unknown, especially given the expenditure of available amoebal derived nutrients and the fastidious nature of Francisella spp. These factors have clear implications for the role of FLA in Francisella environmental persistence

Chlorine inactivation of Escherichia coli O157:H7.

We analyzed isolates of Escherichia coli O157:H7 (which has recently caused waterborne outbreaks) and wild-type E. coli to determine their sensitivity to chlorination. Both pathogenic and nonpathogenic strains were significantly reduced within 1 minute of exposure to free chlorine. Results indicate that chlorine levels typically maintained in water systems are sufficient to inactivate these organisms

Fate of the esophagogastric anastomosis

ObjectiveThe study objective was to evaluate histopathology of the esophagogastric anastomosis after esophagectomy, determine time trends of histologic changes, and identify factors influencing those findings.MethodsA total of 231 patients underwent 468 upper gastrointestinal endoscopies with anastomotic biopsy a median of 3.5 years after esophagectomy. Mean age was 59 ± 12 years, 74% (171) were male, and 96% (222) were white. Seventy-eight percent (179) had esophagectomy for cancer, 13% (30) had chemoradiotherapy, and 13% (30) had prior esophageal surgery. The anastomosis was 20 ± 2.0 cm from the incisors. Anti-reflux medications were used in 59% of patients (276/468) at esophagoscopy. Histopathology was graded as normal (0), consistent with reflux (1), cardia mucosa (2), intestinal metaplasia (3), and dysplasia (4). Repeated-measures nonlinear time-trend analysis and multivariable analyses were used.ResultsGrades 0 and 1 were constant, 5% and 92% at 10 years, respectively. Anti-reflux medication, induction therapy, and higher anastomosis were predictive of less grade 1 histopathology. Grades 2 and 3 increased with time: 12% and 33% at 5 years and 4% and 16% at 10 years, respectively. No variable was predictive of grade 2 or 3 (P > .15) except passage of time. No patient’s condition progressed to dysplasia or cancer.ConclusionsThe esophagogastric anastomosis is subject to gastroesophageal reflux. To minimize histopathologic changes of reflux, the anastomosis should be constructed as high as possible (closer to incisors) and anti-reflux medications prescribed. Surveillance endoscopy, if performed, will document a time-related progression of reflux-related histopathologic changes. However, during surveillance, intestinal metaplasia is uncommon and progression to cancer rare

Esophageal submucosa: The watershed for esophageal cancer

ObjectivesSubmucosal esophageal cancers (pT1b) are considered superficial, implying good survival. However, some are advanced, metastasizing to regional lymph nodes. Interplay of cancer characteristics and lymphatic anatomy may create a watershed, demarcating low-risk from high-risk cancers. Therefore, we characterized submucosal cancers according to depth of invasion and identified those with high likelihood of lymph node metastases and poor survival.MethodsFrom 1983 to 2010, 120 patients underwent esophagectomy for submucosal cancers at Cleveland Clinic. Correlations were sought among cancer characteristics (location, dimensions, histopathologic cell type, histologic grade, and lymphovascular invasion [LVI]), and their associations with lymph node metastasis were identified by logistic regression. Associations with mortality were identified by Cox regression.ResultsAs submucosal invasion increased, cancer length (P < .001), width (P < .001), area (P < .001), LVI (P = .007), and grade (P = .05) increased. Invasion of the deep submucosa (P < .001) and LVI (P = .06) predicted lymph node metastases: 45% (23/51) of deep versus 10% (3/29) of middle-third and 7.5% (3/40) of inner-third cancers had lymph node metastases, as did 46% (12/26) with LVI versus 18% (17/94) without. Older age and lymph node metastases predicted worse 5-year survival: 94% for younger pN0 patients, 62% for older pN0 patients, and 36% for pN1-2 patients regardless of age.ConclusionsSubmucosal cancer characteristics and lymphatic anatomy create a watershed for regional lymph node metastases in the deep submucosa. This previously unrecognized divide distinguishes superficial submucosal cancers with good survival from deep submucosal cancers with poor survival. Aggressive therapy of more superficial cancers is critical before submucosal invasion occurs

High-frequency pressure variations in the vicinity of a surface CO2 flux chamber

We report measurements of 2 Hz pressure fluctuations at and below the soil surface in the vicinity of a surface-based CO2 flux chamber. These measurements were part of a field experiment to examine the possible role of pressure pumping due to atmospheric pressure fluctuations on measurements of surface fluxes of CO2. Under the moderate wind speeds, warm temperatures, and dry soil conditions present at the time of our observations, the chamber had no effect on the pressure field in its near vicinity that could be detected above the level of natural pressure fluctuations in the vicinity. At frequencies at or \u3c2 Hz, pressure fluctuations easily penetrated the soil to depths of several cm with little attenuation. We conclude that the presence of the chamber does not introduce pressure perturbations that lead to biases in measurements of surface fluxes of CO2

Chlorine Inactivation of Highly Pathogenic Avian Influenza Virus (H5N1)

To determine resistance of highly pathogenic avian influenza (H5N1) virus to chlorination, we exposed allantoic fluid containing 2 virus strains to chlorinated buffer at pH 7 and 8, at 5°C. Free chlorine concentrations typically used in drinking water treatment are sufficient to inactivate the virus by >3 orders of magnitude

Developing priority variables ("ecosystem Essential Ocean Variables" — eEOVs) for observing dynamics and change in Southern Ocean ecosystems

Reliable statements about variability and change in marine ecosystems and their underlying causes are needed to report on their status and to guide management. Here we use the Framework on Ocean Observing (FOO) to begin developing ecosystem Essential Ocean Variables (eEOVs) for the Southern Ocean Observing System (SOOS). An eEOV is a defined biological or ecological quantity, which is derived from field observations, and which contributes significantly to assessments of Southern Ocean ecosystems. Here, assessments are concerned with estimating status and trends in ecosystem properties, attribution of trends to causes, and predicting future trajectories. eEOVs should be feasible to collect at appropriate spatial and temporal scales and are useful to the extent that they contribute to direct estimation of trends and/or attribution, and/or development of ecological (statistical or simulation) models to support assessments. In this paper we outline the rationale, including establishing a set of criteria, for selecting eEOVs for the SOOS and develop a list of candidate eEOVs for further evaluation. Other than habitat variables, nine types of eEOVs for Southern Ocean taxa are identified within three classes: state (magnitude, genetic/species, size spectrum), predator–prey (diet, foraging range), and autecology (phenology, reproductive rate, individual growth rate, detritus). Most candidates for the suite of Southern Ocean taxa relate to state or diet. Candidate autecological eEOVs have not been developed other than for marine mammals and birds. We consider some of the spatial and temporal issues that will influence the adoption and use of eEOVs in an observing system in the Southern Ocean, noting that existing operations and platforms potentially provide coverage of the four main sectors of the region — the East and West Pacific, Atlantic and Indian. Lastly, we discuss the importance of simulation modelling in helping with the design of the observing system in the long term. Regional boundary: south of 30°S