Isolation of Bacteriophages for Clinically Relevant Bacteria.

The isolation of bacteriophages targeting most clinically relevant bacteria is reasonably straightforward as long as its targeted host does not have complex chemical, physical, and environmental requirements. Often, sewage, soil, feces, and different body fluids are used for bacteriophage isolation procedures, and following enrichment, it is common to obtain more than a single phage in a sample. This chapter describes a simple method for the enrichment and isolation of bacteriophages from liquid and solid samples that can be adapted for different clinically important aerobic bacteria.

More's the Same-Multiple Hosts Do Not Select for Broader Host Range Phages.

Bacteriophage host range is a result of the interactions between phages and their hosts. For phage therapy, phages with a broader host range are desired so that a phage can infect and kill the broadest range of pathogen strains or related species possible. A common, but not well-tested, belief is that using multiple hosts during the phage isolation will make the isolation of broader host range phage more likely. Using a Bacillus cereus group system, we compared the host ranges of phages isolated on one or four hosts and found that there was no difference in the breadth of host ranges of the isolated phages. Both narrow and broader host range phage were also equally likely to be isolated from either isolation procedure. While there are methods that reliably isolate broader host range phages, such as sequential host isolation, and there are other reasons to use multiple hosts during isolation, multiple hosts are not a consistent way to obtain broader host range phages.

Effect of Mirtazapine on Nausea in Children with Functional Nausea and Functional Dyspepsia Postprandial Distress Syndrome.

OBJECTIVE: The objective of this study was to assess the clinical response and safety of mirtazapine in the pediatric population with a diagnosis of functional nausea and nausea associated with functional dyspepsia postprandial distress syndrome. METHODS: This was a retrospective chart review to evaluate the safety and efficacy of mirtazapine for pediatric nausea and nausea associated with functional dyspepsia postprandial distress syndrome. Clinical response was classified as complete response, partial response, and no response. We also identified the prescribed doses, side effects, and weight changes during mirtazapine therapy. RESULTS: Among the 57 total patients, 67% were females and ages ranged from 7 to 19 years with a mean of 14 ± 3 years. Clinical (complete and partial) response was reported in 82% of patients. Nausea resolved in 82% and insomnia in 77% of the patients. Eighty-four percent gained weight with a mean of 4 ± 7 kg. Sixty-five percent did not report adverse effects. The most common adverse effects were undesired weight gain (16%) and dysphoria (9%). Two patients discontinued the medicine after the first dose because of adverse effects. There was a significant correlation between the initial dose and weight (rs = 0.478; p = 0.0002). The median initial and final doses were 15 mg, respectively. CONCLUSIONS: Mirtazapine is an option for treating children and adolescents with functional nausea and nausea associated with functional dyspepsia post-prandial distress syndrome, especially for a select group of patients with concurrent weight loss, anxiety, and insomnia.

Lubiprostone for Pediatric Functional Constipation: Randomized, Controlled, Double-Blind Study With Long-term Extension.

BACKGROUND & AIMS: Pediatric functional constipation (PFC) is a common problem in children that causes distress and presents treatment challenges to health care professionals. We conducted a randomized, placebo-controlled trial (study 1) in patients with PFC (6-17 years of age) to evaluate the efficacy and safety of lubiprostone, followed by an open-label extension for those who completed the placebo-controlled phase (study 2). METHODS: Study 1 (NCT02042183) was a phase 3, multicenter, randomized, double-blind, placebo-controlled, 12-week study evaluating the efficacy and safety of lubiprostone 12 µg twice daily (BID) and 24 µg BID. Study 2 (NCT02138136) was a phase 3, long-term, open-label extension of study 1. In both studies, lubiprostone doses were based on patients' weight. Efficacy was assessed solely based on study 1, with a primary endpoint of overall spontaneous bowel movement (SBM) response (increase of ≥1 SBM/wk vs baseline and ≥3 SBMs/wk for ≥9 weeks, including 3 of the final 4 weeks). RESULTS: 606 patients were randomized to treatment (placebo: n = 202; lubiprostone: n = 404) in study 1. No statistically significant difference in overall SBM response rate was observed between the lubiprostone and placebo groups (18.5% vs 14.4%; P = .2245). Both the 12-µg BID and 24-µg BID doses of lubiprostone were well tolerated in the double-blind and extension phases, with a safety profile consistent with that seen in adult studies. CONCLUSIONS: Lubiprostone did not demonstrate statistically significant effectiveness over placebo in children and adolescents with PFC but did demonstrate a safety profile similar to that in adults. (ClinicalTrials.gov: Number: NCT02042183; Number: NCT02138136).

The Many Applications of Engineered Bacteriophages-An Overview.

Since their independent discovery by Frederick Twort in 1915 and Felix d'Herelle in 1917, bacteriophages have captured the attention of scientists for more than a century. They are the most abundant organisms on the planet, often outnumbering their bacterial hosts by tenfold in a given environment, and they constitute a vast reservoir of unexplored genetic information. The increased prevalence of antibiotic resistant pathogens has renewed interest in the use of naturally obtained phages to combat bacterial infections, aka phage therapy. The development of tools to modify phages, genetically or chemically, combined with their structural flexibility, cargo capacity, ease of propagation, and overall safety in humans has opened the door to a myriad of applications. This review article will introduce readers to many of the varied and ingenious ways in which researchers are modifying phages to move them well beyond their innate ability to target and kill bacteria.

iKanEat: protocol for a randomized controlled trial of megestrol as a component of a pediatric tube weaning protocol.

BACKGROUND: Although tube feeding routinely saves the lives of children who do not eat by mouth, chronic tube feeding can be a burden to patients, caregivers, and families. Very few randomized trials exist regarding the best methods for weaning children from their feeding tubes. METHODS: The current paper describes a randomized controlled trial of an empirically supported outpatient treatment protocol for moving children from tube to oral eating called iKanEat. Specifically, we describe the methods of randomized double-blind, placebo-controlled trial which includes a 4-week course of megestrol, the only medication used in the iKanEat protocol, to determine whether the addition of megestrol results in improved child outcomes. The primary and secondary aims are to assess the safety and efficacy of megestrol as part of the iKanEat protocol. The third aim is to provide critical information about the impact of the transition from tube to oral feeding on parent stress and parent and child quality of life. DISCUSSION: This trial will provide data regarding whether megestrol is a safe and effective component of the iKanEat tube weaning protocol, as well as important data on how the tube weaning process impacts parent stress and parent and child quality of life. TRIAL REGISTRATION: ClinicalTrials.gov NCT#03815019 . Registered on January 17, 2019.

Virus-Like Particle: Evolving Meanings in Different Disciplines.

Virus-like particle (VLP) is a term that has been in use for about 80 years. Usually, VLP has meant a particle that is like a virus, generally by appearance, but without either proven or actual virus functionality. Initially VLP referred to particles seen in electron microscope images of tissues. More recently, VLP has come to mean other things to other researchers. A key divergence has been use of VLP in association with vaccine and biotechnology applications versus use of VLP in enumeration of viruses in environmental samples. To these viral ecologists, a VLP is a particle that is virus sized, has nucleic acid, and could be a functional virus. But to vaccine developers and biotechnology researchers a VLP instead is a viral structure that intentionally lacks a viral genome. In this study, we look at the history of use of VLP, following changes in meaning as the technology to study VLPs changed.

Self-Efficacy in Children with Functional Constipation Is Associated with Treatment Success.

OBJECTIVES: To assess the relationship between self-efficacy, the belief that an individual can succeed at a goal, and short-term treatment outcome in children with functional constipation. STUDY DESIGN: Patients with functional constipation age 8-16 years completed the Self-Efficacy for Functional Constipation Questionnaire (SEFCQ), consisting of 14 statements about performing tasks needed for defecation. Patients completed SEFCQ before, immediately after, and 3 weeks after their clinic visit. Treatment success was defined as ≥3 bowel movements into the toilet and no fecal incontinence in the third week. RESULTS: 75% of patients had a successful outcome. Scores were higher in the group that was successful than in those that failed before, immediately after the visit, and 3 weeks later (P < .001). Self-efficacy improved at all time points in the group that was successful (P < .001). In the group that failed, scores improved immediately after clinic visit (P < .01) but were unchanged at follow-up (P > .05). CONCLUSIONS: Improved self-efficacy is associated with successful outcomes in children with functional constipation, thus, it may be beneficial to enhance self-efficacy for defecation during treatment.

Phages for Phage Therapy: Isolation, Characterization, and Host Range Breadth.

For a bacteriophage to be useful for phage therapy it must be both isolated from the environment and shown to have certain characteristics beyond just killing strains of the target bacterial pathogen. These include desirable characteristics such as a relatively broad host range and a lack of other characteristics such as carrying toxin genes and the ability to form a lysogen. While phages are commonly isolated first and subsequently characterized, it is possible to alter isolation procedures to bias the isolation toward phages with desirable characteristics. Some of these variations are regularly used by some groups while others have only been shown in a few publications. In this review I will describe (1) isolation procedures and variations that are designed to isolate phages with broader host ranges, (2) characterization procedures used to show that a phage may have utility in phage therapy, including some of the limits of such characterization, and (3) results of a survey and discussion with phage researchers in industry and academia on the practice of characterization of phages.

Serum-derived bovine immunoglobulin for children with diarrhea-predominant irritable bowel syndrome.

BACKGROUND: Oral serum-derived bovine immunoglobulin (SBI)/protein isolate is a medical food intended to manage chronic diarrhea. It has been shown to improve pain and diarrhea in adults with diarrhea-predominant irritable bowel syndrome (d-IBS). AIM: To determine if SBI can improve symptoms in children with d-IBS. METHODS: We performed a randomized, double-blind, placebo-controlled, pilot study (NCT02609529) to evaluate the effectiveness of SBI in children 8-18 years with d-IBS. We recorded stool number, abdominal pain, and stool form in all patients for 1 week and then assigned the patients at a ratio of 2:1 to treatment with SBI 5 g BID or placebo for 3 weeks. The patients and their parents completed the Pediatric Quality of Life Inventory™ for Gastrointestinal Symptoms (PedsQOL) and the Pediatric Functional Disability Index (FDI). In addition, complete blood counts and serum chemistries were recorded at the start and end of treatment to evaluate safety. RESULTS: Fifteen patients (nine SBI, six placebo) completed the study. Both SBI and placebo groups reported nonstatistical reductions in stool frequency per week. The SBI group showed a significant reduction in stool frequency at weeks 1 and 2 but not at the end of treatment. The SBI group also demonstrated statistical improvements in abdominal pain and stool form by 3 weeks. The placebo group did not achieve similar improvements. The overall FDI and PedsQOL scores, as well as PedsQOL subscale scores for pain, discomfort when eating, diarrhea, worry about stomach aches, and communication, improved significantly in the SBI group, but not in the placebo group. No serious adverse events occurred. Serum chemistries and hemograms were normal at baseline and at the end of study in all patients. CONCLUSION: In this single-center, exploratory pilot study, we demonstrated that 10 g SBI per day was safe in children with d-IBS and improved symptoms. Larger studies, with longer treatment duration, seem warranted based on these initial positive results.

Prevalence of Pediatric Functional Gastrointestinal Disorders Utilizing the Rome IV Criteria.

OBJECTIVE: To assess the prevalence of functional gastrointestinal (GI) disorders in children 0-18 years old according to the newly established Rome IV diagnostic criteria as reported by parents in a representative community sample. STUDY DESIGN: A cross-sectional study in which mothers (n = 1255) of children aged 0-18 years old in the US were recruited to complete an online survey about their child's GI symptoms, quality of life (QoL), and other health conditions. RESULTS: Based on the Rome IV criteria, 24.7% of infants and toddlers aged 0-3 years and 25.0% of children and adolescents aged 4-18 years fulfilled symptom-based criteria for a functional GI disorder. The most common functional GI disorders were infant regurgitation among infants (24.1%) and functional constipation among both toddlers (18.5%) and children and adolescents (14.1%). QoL was diminished in pediatric patients with functional GI disorders (median = 71.69 vs median = 87.60; z = -11.41; P < .001). Children were more likely to qualify for a functional GI disorder if their parent qualified for a functional GI disorder (35.4% vs 23.0%; P < .001). CONCLUSIONS: Based on Rome IV criteria, functional GI disorders are common in pediatric populations of all ages and are associated with decreased QoL.

Bacteriophage T4 long tail fiber domains.

Bacteriophage T4 initially recognizes its host cells using its long tail fibers. Long tail fibers consist of a phage-proximal and a phage-distal rod, each around 80 nm long and attached to each other at a slight angle. The phage-proximal rod is formed by a homo-trimer of gene product 34 (gp34) and is attached to the phage-distal rod by a monomer of gp35. The phage-distal rod consists of two protein trimers: a trimer of gp36, attached to gp35, although most of the phage-distal rod, including the receptor-binding domain, is formed by a trimer of gp37. In this review, we discuss what is known about the detailed structure and function of the different long tail fiber domains. Partial crystal structures of gp34 and gp37 have revealed the presence of new protein folds, some of which are present in several repeats, while others are apparently unique. Gp38, a phage chaperone protein necessary for folding of gp37, is thought to act on an α-helical coiled-coil region in gp37. Future studies should reveal the remaining structure of the long tail fibers, how they assemble into a functional unit, and how the long tail fibers trigger the infection process after successful recognition of a suitable host bacterium.

Water Load Test in Children with Chronic Abdominal Pain or Obesity Compared with Nonobese Controls.

OBJECTIVE: Satiety is the perception of satisfied fullness and represents a summation of neural and hormonal influences. Satiety can be assessed by drink tests, including water load. The objective of our study was to confirm the difference in water load volume between nonobese control children and children with functional dyspepsia (FD), children with irritable bowel syndrome (IBS), and obese children. METHODS: A total of 158 children ages 6 to 13 years participated in the study. There were 43 children with FD, 25 with IBS, 44 obese children, and 46 nonobese age-matched control children. Subjects drank as much water as possible in 3 minutes or until their stomachs felt full. RESULTS: Children in the FD and IBS groups drank less water than did the nonobese controls; the obese children drank more water than did the nonobese controls. The water load test demonstrated high specificity but poor sensitivity in predicting children with FD. CONCLUSIONS: A water load test offers a simple, noninvasive research tool to measure satiety. Children with chronic abdominal pain drank less than nonobese control children; however, the water load test did not discriminate between FD and IBS. Obese children drank more water than the other groups, suggesting the possibility of an underlying abnormality in the perception of satiety.

Rumination Syndrome and Dental Erosions in Children.

Rumination syndrome is the effortless regurgitation of recently ingested food with subsequent reswallowing or spitting out. Dental erosion (DE) affects 2% to 5% of the population. DE is defined as loss of tooth structure by a chemical process that does not involve bacteria. Our objective was to compare the frequency of DE among children with rumination syndrome with healthy controls. We enrolled 30 patients 4 to 21 years of age diagnosed with rumination syndrome, and 30 age- and sex-matched healthy control subjects. Patients were evaluated by pediatric dentists for presence of DE with Taji et al a validated grading system. Patients with rumination were more likely to have DE (P < 0.001). Of patients with rumination syndrome, 23 (77%) had DE, compared with 4 (13%) control subjects. DEs are more frequent in patients with rumination syndrome.

Biliary Dyskinesia in Children: A Systematic Review.

Cholecystectomy rates for biliary dyskinesia in children are rising in the United States, but not in other countries. Biliary dyskinesia is a validated functional gallbladder disorder in adults, requiring biliary colic in the diagnosis. In contrast, most studies in children require upper abdominal pain, absent gallstones on ultrasound, and an abnormal gallbladder ejection fraction (GBEF) on cholecystokinin-stimulated cholescintigraphy for diagnosis. We aimed to systematically review existing literature in biliary dyskinesia in children, determine the validity and reliability of diagnostic criteria, GBEF, and to assess outcomes following cholecystectomy. We performed a systematic review following the PRISMA checklist and searched 7 databases including PubMed, Scopus, Embase, Ovid, MEDLINE, ProQuest, Web of Science, and the Cochrane library. Bibliographies of articles were screened for additional studies. Our search terms yielded 916 articles of which 28 were included. Three articles were manually added from searched references. We reviewed 31 peer-reviewed publications, all retrospective chart reviews. There was heterogeneity in diagnostic criteria and GBEF values. Outcomes after laparoscopic cholecystectomy varied from 34% to 100% success, and there was no consensus concerning factors influencing outcomes. The observational, retrospective study designs that comprised our review limited interpretation of safety and efficacy of the investigations and treatment in biliary dyskinesia in children. Symptoms of biliary dyskinesia overlapped with functional dyspepsia. There is a need for consensus on symptoms defining biliary dyskinesia, validation of testing required for diagnosis of biliary dyskinesia, and randomized controlled trials comparing medical versus surgical management in children with upper abdominal pain.

The endolysin from the Enterococcus faecalis bacteriophage VD13 and conditions stimulating its lytic activity.

Bacteriophages produce endolysins (peptidoglycan hydrolases) to lyse the host cell from within and release nascent bacteriophage particles. Recombinant endolysins can lyse Gram-positive bacteria when added exogenously. As a potential alternative antimicrobial, we cloned and expressed the enterococcal VD13 bacteriophage endolysin. VD13 endolysin has a CHAP catalytic domain with 92% identity with the bacteriophage IME-EF1 endolysin. The predicted size of VD13 endolysin is ∼27 kDa as verified by SDS-PAGE. The VD13 endolysin lyses Enterococcus faecalis strains, but not E. faecium or other non-enterococci. VD13 endolysin has activity from pH 4 to pH 8, with peak activity at pH 5, and exhibits greater activity in the presence of calcium. Optimum activity at pH 5 occurs in the absence of NaCl. VD13 endolysin, in ammonium acetate (C2H3O2NH4) calcium chloride (CaCl2) buffer pH 5, is stimulated to higher activity upon heating at temperatures up to 65°C for 30 min, whereas activity is lost upon heating to 42°C, in pH 7 buffer.