Acute gastroenteritis

Donnan Potential across the Outer Membrane of Gram-Negative Bacteria and Its Effect on the Permeability of Antibiotics

The cell envelope structure of Gram-negative bacteria is unique, composed of two lipid bilayer membranes and an aqueous periplasmic space sandwiched in between. The outer membrane constitutes an extra barrier to limit the exchange of molecules between the cells and the exterior environment. Donnan potential is a membrane potential across the outer membrane, resulted from the selective permeability of the membrane, which plays a pivotal role in the permeability of many antibiotics. In this review, we discussed factors that affect the intensity of the Donnan potential, including the osmotic strength and pH of the external media, the osmoregulated periplasmic glucans trapped in the periplasmic space, and the displacement of cell surface charges. The focus of our discussion is the impact of Donnan potential on the cellular permeability of selected antibiotics including fluoroquinolones, tetracyclines, β-lactams, and trimethoprim.

A Review on the Management of Acute Gastroenteritis in Children

Acute gastroenteritis represents a frequent cause of morbidity among children in Hong Kong. Despite the large number of potential etiologic agents, principles of management of gastroenteritis are uniform and aim to prevent the two major complications - dehydration and malnutrition. A review of the literature was performed. Selected articles were appraised, graded, and synthesised qualitatively. Statements on recommendations were generated. Current evidence emphasises the use of oral rehydration and the early reintroduction of age-appropriate foods. Apart from these two, important aspects of management reviewed included laboratory investigations, role of anti-diarrhoeal agents, and use of antimicrobial agents. Criteria for admission of high-risk children are also addressed.

The significance of serum and fecal levels of interleukin-6 and interleukin-8 in hospitalized children with acute rotavirus and norovirus gastroenteritis

BACKGROUND

Rotavirus and norovirus are the most common known causes of viral gastroenteritis in children. This study examined the association between serum interleukin 6 (IL-6) and interleukin 8 (IL-8) levels and disease severity in the acute phase of rotavirus and norovirus gastroenteritis in children, and it also explored the role of fecal cytokine levels in children with viral and bacterial gastroenteritis.

METHODS

This prospective study enrolled patients aged 4 months to 14 years admitted with acute gastroenteritis in a tertiary care center. Peripheral blood samples were collected for IL-6 and IL-8 assays within the first 3 days of diarrhea. Stool samples were obtained from the patients in the first 24 hours after admission.

RESULTS

Serum IL-6 and IL-8 were measured in children with viral (n = 66) and bacterial (n = 23) infections, and in healthy controls (n = 10). In the acute phase of gastroenteritis, a moderately positive correlation was found between serum IL-6 levels and disease severity (rs = 0.41, p < 0.01). Serum IL-8 levels correlated with the duration of fever (rs = 0.28, p = 0.03). Fecal IL-6 levels correlated with the maximum number of daily bowel movements (rs = 0.35, p < 0.05). Rotavirus infection induced significantly higher serum IL-8 levels than norovirus infection (p < 0.05). Receiver operating characteristic (ROC) curve analysis showed that absolute neutrophil count (ANC), maximum body temperature (BT), and Vesikari score were significant predictors in discriminating rotavirus from norovirus gastroenteritis.

CONCLUSION

IL-6 and IL-8 are involved in the pathogenesis of acute gastroenteritis in both rotavirus and norovirus. An ANC of less than 9000/mm(3), maximum BT of less than 38.2°C, and Vesikari score of less than 14 at the end of the course are potential predictors of norovirus infection in children compared with rotavirus gastroenteritis.

Pre-admission therapy for childhood acute diarrhoea--a hospital-based study

Acute gastroenteritis (AGE) is a common illness among infants and children contributing to significant mortality and morbidity. As such, appropriate treatment received prior to hospital admission is of utmost importance. This retrospective observational study aimed to determine preadmission management in paediatric patients prior to hospital admission. Two hundred and twenty-two case notes of paediatric AGE patients were reviewed over a 12-month period. One hundred and fifty-four patients received medications prior to admission with 143 (92.9%) patients received known classes of medications. Antipyretic agents were the most commonly prescribed (69.2%), followed by antibiotics (38.5%), anti-emetics (35.7%), oral rehydration salts (29.4%) and antidiarrhoeals (28.0%). The mean duration of stay in hospital was slightly shorter in patients, who received prior medications than those who did not (2.22 vs. 2.32 days respectively). Seventy per cent of children admitted for AGE were treated suboptimally prior to hospital admission with oral rehydration salts being largely under-utilized, despite their proven efficacy and safety. Sex, race and age had no influence on the type of preadmission treatment. A greater effort should be made to educate the general public in the appropriate treatment of AGE.

Microbial Etiology of Acute Gastroenteritis in Hospitalized Children in Taiwan

BACKGROUND/PURPOSE

Viral infections are the most common causes of acute infectious diarrhea in the pediatric population. To explore any possible microbial etiologies of acute gastroenteritis in children, we detected stool viral antigen including rotavirus, adenovirus, norovirus and astrovirus. We also studied the possible precipitating factors.

METHODS

During a period of 1 year (from October 2003 to September 2004), children from birth to 15 years old admitted to the pediatric ward were prospectively surveyed. Stool specimens were collected within 48 hours after admission and then frozen at -40 degrees C until analysis. Enzyme immunoassay was used to detect rotavirus, astrovirus, norovirus and adenovirus. Bacterial culture was performed at the same time.

RESULTS

During the study period, 82 stool samples were collected due to acute gastroenteritis and fit the definition of a diarrhea episode. Forty-two (51.2%) patients with viral infection, 11 (13.4%) with bacterial infection, and six (7.3%) with mixed viral and bacterial infection were detected. The most prevalent virus was rotavirus (35.4%), followed by norovirus (29.3%). The most prevalent cause of bacterial infection was Salmonella (19.5%). With regard to clinical severity, rotavirus resulted in longer hospital stay, higher rate of vomiting, stool occult blood, leukocytosis, lower rate in stool pus cell, and C-reactive protein elevation more than 5 mg/dL as compared with norovirus. Only the difference in hospital stay reached significant statistical difference.

CONCLUSION

Norovirus is an important cause of acute gastroenteritis in children, although rotavirus is still the leading cause of pediatric acute gastroenteritis.

The home management and characteristics of children presenting to hospital with acute gastroenteritis

Large numbers of Australian children are admitted to hospital with acute gastroenteritis. This study aimed to describe the home management of children with acute gastroenteritis prior to presentation at a paediatric hospital. Parents received inadequate information regarding fluid rehydration, particularly from general practitioners, and there was a lack of parental awareness in relation to ORS usage. Children attending childcare were over represented among the sample. The majority of children were only mildly dehydrate presentation to hospital. Education programs are needed to increase community awareness ORS and improve home management of acute gastroenteritis.

Acute gastroenteritis in children : what role for antibacterials?

The aim of this article is to define the currently accepted role of antibacterials in the treatment of acute gastroenteritis in children. Most cases of acute gastroenteritis in children are viral, self-limited, and need only supportive treatment. Appropriate fluid and electrolyte therapy, with close attention to nutrition, remain central to therapy.Antibacterial therapy serves as an adjunct, to shorten the clinical course, eradicate causative organisms, reduce transmission, and prevent invasive complications. Selection of antibacterials to use in acute bacterial gastroenteritis is based on clinical diagnosis of the likely pathogen prior to definitive laboratory results. Antibacterial therapy should be restricted to specific bacterial pathogens and disease presentations. In general, infections with Shigella spp. and Vibrio cholera should usually be treated with antibacterials, while antibacterials are only used in severe unresponsive infections with Salmonella, Yersinia, Aeromonas, Campylobacter, Plesiomonas spp., and Clostridium difficile. Antibacterials should be avoided in enterohemorrhagic Escherichia coli infection. However, empiric therapy may be appropriate in the presence of a severe illness with bloody diarrhea and stool leucocytes, particularly in infancy and the immunocompromised. The benefits and risks of adverse drug reactions should be weighed before prescribing antibacterials. Moreover, a major concern is the emergence of antibacterial-resistant strains due to the widespread use of antibacterial agents.

A multicenter randomized controlled trial of a liquid loperamide product versus placebo in the treatment of acute diarrhea in children

This randomized, double-blind, placebo-controlled trial of 48 hours' duration conducted in 13 primary care ambulatory practices in the United States and Mexico was used to compare the efficacy and safety of loperamide with placebo for the treatment of acute diarrhea in children aged 2 through 11 years. Two hundred fifty-eight children with acute nonspecific diarrhea were enrolled. Children were randomly assigned to treatment with loperamide HCl 0.5 mg/5 mL (n = 130) or placebo (n = 128). The first dose of loperamide consisted of either 1.0 mg (children 2 through 5 years of age) or 2.0 mg (children 6 through 11 years of age) of study medication under the observation of study personnel. This was followed by 1 mg after each unformed stool, with a total daily dose of up to 3.0 mg in the children 2-5 years of age, 4.0 mg in the children 6-8 years of age, and 6.0 mg in the children 9-11 years of age. The primary outcome measures were time to last unformed stool, time to first unformed stool, number of unformed stools during six consecutive 8-hour periods, and overall rating of efficacy/acceptability. Secondary outcomes included abdominal pain/cramping, vomiting, and fever. Children who received loperamide had significantly shorter time to last unformed stool (p = 0.0017) and fewer numbers of unformed stools (p = 0.0237) than children who received placebo. The end-of-study overall efficacy/acceptability rating of loperamide was significantly better than for placebo (p = 0.0107). All other clinically important outcome measures related to diarrhea relief favored loperamide. There was no significant difference in the incidence of drug-related adverse events between treatment groups, although total adverse events were reported more frequently (p = 0.048) by the loperamide group (15%) compared with the placebo group (7%). In conclusion, this controlled study provides data demonstrating that at recommend doses, loperamide is well tolerated and significantly shortens the duration and severity of symptoms of acute nonspecific diarrhea in children 2 through 11 years of age.