The Entomopathogenic Bacterial Endosymbionts Xenorhabdus and Photorhabdus: Convergent Lifestyles from Divergent Genomes

Members of the genus Xenorhabdus are entomopathogenic bacteria that associate with nematodes. The nematode-bacteria pair infects and kills insects, with both partners contributing to insect pathogenesis and the bacteria providing nutrition to the nematode from available insect-derived nutrients. The nematode provides the bacteria with protection from predators, access to nutrients, and a mechanism of dispersal. Members of the bacterial genus Photorhabdus also associate with nematodes to kill insects, and both genera of bacteria provide similar services to their different nematode hosts through unique physiological and metabolic mechanisms. We posited that these differences would be reflected in their respective genomes. To test this, we sequenced to completion the genomes of Xenorhabdus nematophila ATCC 19061 and Xenorhabdus bovienii SS-2004. As expected, both Xenorhabdus genomes encode many anti-insecticidal compounds, commensurate with their entomopathogenic lifestyle. Despite the similarities in lifestyle between Xenorhabdus and Photorhabdus bacteria, a comparative analysis of the Xenorhabdus, Photorhabdus luminescens, and P. asymbiotica genomes suggests genomic divergence. These findings indicate that evolutionary changes shaped by symbiotic interactions can follow different routes to achieve similar end points

Analysis of Factors Influencing Agritourism Businesses Perceptions about Expansion

Agritourism can provide both on-farm recreational activities for visitors and educational activities showing how food is produced. It can help farmers diversify and add income to their operations. This study assesses how characteristics of agritourism operations and perceived barriers may influence future plans to expand using a logit model. This information will be useful to policymakers and economic development professionals, as they look for contributors to future growth in the agritourism sector, as well as special assistance needs by expansion-minded firms

Virulence factors of Escherichia coli isolates that produce CTX-M-type extended-spectrum β-lactamases

This study determined the phylogenetic groups and virulence factors of 37 Escherichia coli isolates producing types of CTX-M compared with those of 19 isolates producing different types of extended-spectrum β-lactamases (ESBLs) in a well-defined North American population. Most CTX-M-14 producers (97%) were from phylogenic group D; 67% of the CTX-M-15 producers were from group B2. A single CTX-M-14-producing strain belonged to clonal group A. There were significant prevalence differences for individual virulence factors among CTX-M producers and nonproducers; however, aggregate virulence factor scores were similar. CTX-M producers more commonly caused repeat urinary tract infections. Our results indicate that CTX-M type predicts phylogenetic background, and the virulence potential of ESBL-producing E. coli isolates is a complex issue, requiring further study and ongoing surveillance.</p

Xenorhabdus nematophila Requires an Intact iscRSUA-hscBA-fdx Operon To Colonize Steinernema carpocapsae Nematodes

An insertion between iscA and hscB of the Xenorhabdus nematophila iscRSUA-hscBA-fdx locus, predicted to encode Fe-S assembly machinery, prevented colonization of Steinernema carpocapsae nematodes. The insertion disrupted cotranscription of iscA and hscB, but did not reduce hscBA expression, suggesting that X. nematophila requires coordinated expression of the isc-hsc-fdx locus for colonization

Alignment of parent- and child-reported outcomes and histology in eosinophilic esophagitis across multiple CEGIR sites.

BACKGROUND:Patient-reported outcome metrics for eosinophilic esophagitis (EoE) have been developed and validated but not used in a multicenter pediatric population or systematically aligned with histology. OBJECTIVE:We sought to understand (1) the potential of caregiver report to predict patient self-reported symptoms and (2) the correlation of patient-reported outcome domains with histology. METHODS:Patients with EoE (n = 310) and their parents participating in the Consortium of Gastrointestinal Eosinophilic Disease Researchers (CEGIR) observational clinical trial were queried for baseline patient symptoms and quality of life (QOL) by using the Pediatric Eosinophilic Esophagitis Symptom Score, version 2 (PEESSv2.0), and the Pediatric QOL EoE module (PedsQL-EoE), and biopsy specimens were analyzed by using the EoE Histology Scoring System. RESULTS:PEESSv2.0 parental and child reports aligned across all domains (r = 0.68-0.73, P &lt; .001). PedsQL-EoE reports correlated between parents and children across ages and multiple domains (r = 0.48-0.79, P &lt; .001). There was a tight correlation between symptoms on PEESSv2.0 and their effects on QOL both on self-report and parental report (P &lt; .001). Self-reported symptoms on PEESSv2.0 (positively) and PedsQL-EoE (inversely) showed a weak correlation with proximal, but not distal, peak eosinophil counts and features and architectural tissue changes on the EoE Histology Scoring System (P &lt; .05). CONCLUSIONS:Parents of children with EoE aged 3 to 18 years accurately reflected their children's disease symptoms and QOL. Self- and parent-reported symptoms correlate with proximal esophageal histology. Our data suggest that parental report in young children can function as an adequate marker for self-reported symptoms and that self-reported symptoms can reflect changes in tissue histology in the proximal esophagus. These findings should be considered during clinical trials for drug development

Contemporary Outcomes After Partial Resection of Infected Aortic Grafts

Introduction: Aortic graft infection remains a considerable clinical challenge, and it is unclear which variables are associated with adverse outcomes among patients undergoing partial resection. Methods: A retrospective, multi-institutional study of patients who underwent partial resection of infected aortic grafts from 2002 to 2014 was performed using a standard database. Baseline demographics, comorbidities, operative, and postoperative variables were recorded. The primary outcome was mortality. Descriptive statistics, Kaplan-Meier (KM) survival analysis, and Cox regression analysis were performed. Results: One hundred fourteen patients at 22 medical centers in 6 countries underwent partial resection of an infected aortic graft. Seventy percent were men with median age 70 years. Ninety-seven percent had a history of open aortic bypass graft: 88 (77%) patients had infected aortobifemoral bypass, 18 (16%) had infected aortobiiliac bypass, and 1 (0.8%) had an infected thoracic graft. Infection was diagnosed at a median 4.3 years post-implant. All patients underwent partial resection followed by either extra-anatomic (47%) or in situ (53%) vascular reconstruction. Median follow-up period was 17 months (IQR 1, 50 months). Thirty-day mortality was 17.5%. The KM-estimated median survival from time of partial resection was 3.6 years. There was no significant survival difference between those undergoing in situ reconstruction or extra-anatomic bypass (P = 0.6). During follow up, 72% of repairs remained patent and 11% of patients underwent major amputation. On univariate Cox regression analysis, Candida infection was associated with increased risk of mortality (HR 2.4; P = 0.01) as well as aortoenteric fistula (HR 1.9, P = 0.03). Resection of a single graft limb only to resection of abdominal (graft main body) infection was associated with decreased risk of mortality (HR 0.57, P = 0.04), as well as those with American Society of Anesthesiologists classification less than 3 (HR 0.35, P = 0.04). Multivariate analysis did not reveal any factors significantly associated with mortality. Persistent early infection was noted in 26% of patients within 30 days postoperatively, and 39% of patients were found to have any post-repair infection during the follow-up period. Two patients (1.8%) were found to have a late reinfection without early persistent postoperative infection. Patients with any post-repair infection were older (67 vs . 60 years, P = 0.01) and less likely to have patent repairs during follow up (59% vs. 32%, P = 0.01). Patients with aortoenteric fistula had a higher rate of any post-repair infection (63% vs . 29%, P &lt; 0.01) Conclusion: This large multi-center study suggests that patients who have undergone partial resection of infected aortic grafts may be at high risk of death or post-repair infection, especially older patients with abdominal infection not isolated to a single graft limb, or with Candida infection or aortoenteric fistula. Late reinfection correlated strongly with early persistent postoperative infection, raising concern for occult retained infected graft material