Impact of Rotaviral Diarrhea on Child Growth in Sub-Saharan Africa and South Asia in the Global Enteric Multicenter Study

Rotavirus is the leading cause of dehydrating diarrhea among children in developing countries. The impact of rotaviral diarrhea on nutritional status is not well understood. We aimed to determine the association between rotavirus-positive moderate-to-severe diarrhea and nutrition in children under 5 years of age. We analyzed data from the Global Enteric Multicenter Study on children 0-59 months old from South Asia and sub-Saharan Africa. The relationships between explanatory variables and outcome variables were assessed using multiple linear regression; the explanatory variable was the presence of rotavirus in the stool sample, and the outcome variables were z scores [length/height-for-age (LAZ/HAZ), weight-for-age (WAZ), and weight-for-length/height (WLZ/WHZ)] at follow-up (∼60 days). The prevalence of rotaviral diarrhea was 17.3% (905/5,219) in South Asia and 19.95% (842/4,220) in sub-Saharan Africa. Rotavirus was associated with higher LAZ/HAZ (β: 0.19; 95% CI: 0.12, 0.26; P <0.001) and WAZ (β: 0.15; 95% CI: 0.79, 0.22; P <0.001) in sub-Saharan Africa and with lower WLZ/WHZ (β coefficient: -0.08; 95% CI: -0.15, -0.009; P = 0.027) in South Asia. Our study indicates that rotaviral diarrhea is positively associated with nutritional status in sub-Saharan Africa and is negatively associated with nutritional status in South Asia. An expedited implementation policy of ongoing preventive and control strategies, including vaccination against rotavirus, is necessary to reduce the burden of rotaviral diarrhea, which may further help to reduce the potential nutritional ramifications.

Bubble continuous positive airway pressure for children with severe pneumonia and hypoxaemia in Bangladesh: an open, randomised controlled trial

BACKGROUND

In developing countries, mortality in children with very severe pneumonia is high, even with the provision of appropriate antibiotics, standard oxygen therapy, and other supportive care. We assessed whether oxygen therapy delivered by bubble continuous positive airway pressure (CPAP) improved outcomes compared with standard low-flow and high-flow oxygen therapies.

METHODS

This open, randomised, controlled trial took place in Dhaka Hospital of the International Centre for Diarrhoeal Disease Research, Bangladesh. We randomly assigned children younger than 5 years with severe pneumonia and hypoxaemia to receive oxygen therapy by either bubble CPAP (5 L/min starting at a CPAP level of 5 cm H2O), standard low-flow nasal cannula (2 L/min), or high-flow nasal cannula (2 L/kg per min up to the maximum of 12 L/min). Randomisation was done with use of the permuted block methods (block size of 15 patients) and Fisher and Yates tables of random permutations. The primary outcome was treatment failure (ie, clinical failure, intubation and mechanical ventilation, death, or termination of hospital stay against medical advice) after more than 1 h of treatment. Primary and safety analyses were by intention to treat. We did two interim analyses and stopped the trial after the second interim analysis on Aug 3, 2013, as directed by the data safety and monitoring board. This trial is registered at ClinicalTrials.gov, number NCT01396759.

FINDINGS

Between Aug 4, 2011, and July 17, 2013, 225 eligible children were recruited. We randomly allocated 79 (35%) children to receive oxygen therapy by bubble CPAP, 67 (30%) to low-flow oxygen therapy, and 79 (35%) to high-flow oxygen therapy. Treatment failed for 31 (14%) children, of whom five (6%) had received bubble CPAP, 16 (24%) had received low-flow oxygen therapy, and ten (13%) had received high-flow oxygen therapy. Significantly fewer children in the bubble CPAP group had treatment failure than in the low-flow oxygen therapy group (relative risk [RR] 0·27, 99·7% CI 0·07-0·99; p=0·0026). No difference in treatment failure was noted between patients in the bubble CPAP and those in the high-flow oxygen therapy group (RR 0·50, 99·7% 0·11-2·29; p=0·175). 23 (10%) children died. Three (4%) children died in the bubble CPAP group, ten (15%) children died in the low-flow oxygen therapy group, and ten (13%) children died in the high-flow oxygen therapy group. Children who received oxygen by bubble CPAP had significantly lower rates of death than the children who received oxygen by low-flow oxygen therapy (RR 0·25, 95% CI 0·07-0·89; p=0·022).

INTERPRETATION

Oxygen therapy delivered by bubble CPAP improved outcomes in Bangladeshi children with very severe pneumonia and hypoxaemia compared with standard low-flow oxygen therapy. Use of bubble CPAP oxygen therapy could have a large effect in hospitals in developing countries where the only respiratory support for severe childhood pneumonia and hypoxaemia is low-flow oxygen therapy. The trial was stopped early because of higher mortality in the low-flow oxygen group than in the bubble CPAP group, and we acknowledge that the early cessation of the trial reduces the certainty of the findings. Further research is needed to test the feasibility of scaling up bubble CPAP in district hospitals and to improve bubble CPAP delivery technology.

FUNDING

International Centre for Diarrhoeal Disease Research, Bangladesh, and Centre for International Child Health, University of Melbourne.

Phenotypic and genotypic characteristics of Vibrio cholerae O1 isolated from the Sierra Leone cholera outbreak in 2012

BACKGROUND

This study describes phenotypic, genotypic and antibiotic susceptibility patterns of the strains isolated from the 2012 Sierra Leone cholera outbreak. Rectal swabs were collected from patients and cultured for Vibrio cholerae O1.

METHODS

The isolates were subjected to multiplex PCR, mismatch amplification mutation assay (MAMA) PCR, pulsed field gel electrophoresis (PFGE), and antibiotic sensitivity tests using disk diffusion and minimum inhibitory concentration (MIC) E-test following standard procedures.

RESULTS

Out of 17 rectal swabs tested, 15 yielded V. cholerae O1 biotype El Tor, serotype Ogawa. All the strains belonged to 'altered' variants as MAMA PCR result showed the presence of classical cholera toxin B. PFGE result revealed four pulse types. Using antibiotic disk diffusion, all the isolates were resistant to erythromycin, chloramphenicol, furazolidone, and trimethoprim/sulfamethoxazole (SXT) except SL1 which was sensitive to chloramphenicol and SXT. All the isolates were sensitive to nalidixic acid, tetracycline, doxycycline, azithromycin, and ciprofloxacin except SL2 which was resistant to nalidixic acid. However, variable sensitivity patterns were observed for kanamycin. The ranges of MIC were 0.125-0.50 mg/l, 0.003-0.023 mg/l and 0.38-0.75 mg/l for azithromycin, ciprofloxacin and tetracycline, respectively.

CONCLUSIONS

This study demonstrates that altered variants of V. cholerae O1 of four clonal types were responsible for the 2012 outbreak of cholera in Sierra Leone.

Specialist hospital study shows that septic shock and drowsiness predict mortality in children under five with diarrhoea

AIM

To evaluate the clinical characteristics and outcome in children hospitalised with diarrhoea, comparing those developed septic shock with those who did not.

METHODS

We carried out a retrospective chart review on children aged 0-59 months admitted to the Dhaka Hospital, International Centre for Diarrhoeal Diseases Research, Bangladesh, with diarrhoea between October 2010 and September 2011. They were included if they had severe sepsis defined as tachycardia plus hyperthermia or hypothermia or an abnormal white blood cell count plus poor peripheral perfusion in absence of dehydration. Patients unresponsive to fluid and boluses, who required inotropes, were categorised as having septic shock (n = 88). The controls were those without septic shock (n = 116).

RESULTS

Death was significantly higher among the children with septic shock (67%) than the controls (14%) (p < 0.001). A logistic regression analysis, adjusted for potential confounders, found that children with septic shock were more likely to be drowsy on admission and received blood transfusions and mechanical ventilation (all p < 0.05).

CONCLUSION

Children hospitalised for diarrhoea with septic shock were more likely to die, be drowsy on admission and receive blood transfusions and mechanical ventilation. A randomised clinical trial on inotropes in children with diarrhoea, severe sepsis and drowsiness may expedite their use and prevent mechanical ventilation and deaths.

Prevalence, clinical predictors, and outcome of hypocalcaemia in severely-malnourished under-five children admitted to an urban hospital in Bangladesh: a case-control study

Hypocalcaemia is common in severely-malnourished children and is often associated with fatal outcome. There is very limited information on the clinical predicting factors of hypocalcaemia in hospitalized severely-malnourished under-five children. Our objective was to evaluate the prevalence, clinical predicting factors, and outcome of hypocalcaemia in such children. In this case-control study, all severely-malnourished under-five children (n=333) admitted to the Longer Stay Ward (LSW), High Dependency Unit (HDU), and Intensive Care Unit (ICU) of the Dhaka Hospital of icddr,b between April 2011 and April 2012, who also had their total serum calcium estimated, were enrolled. Those who presented with hypocalcaemia (serum calcium <2.12 mmol/L) constituted the cases (n=87), and those admitted without hypocalcaemia (n=246) constituted the control group in our analysis. The prevalence of hypocalcaemia among severely-malnourished under-five children was 26% (87/333). The fatality rate among cases was significantly higher than that in the controls (17% vs 5%; p < 0.001). Using logistic regression analysis, after adjusting for potential confounders, such as vomiting, abdominal distension, and diastolic hypotension, we identified acute watery diarrhoea (AWD) (OR 2.19, 95% CI 1.08-4.43, p = 0.030), convulsion on admission (OR 21.86, 95% CI 2.57-185.86, p = 0.005), and lethargy (OR 2.70, 95% CI 1.633-5.46, p = 0.006) as independent predictors of hypocalcaemia in severely-malnourished children. It is concluded, severely-malnourished children presenting with hypocalcaemia have an increased risk of death than those without hypocalcaemia. AWD, convulsion, and lethargy assessed on admission to hospital are the clinical predictors of hypocalcaemia in such children. Presence of these features in hospitalized children with severe acute malnutrition (SAM) should alert clinicians about the possibility of hypocalcaemia and may help undertake potential preventive measures, such as calcium supplementation, in addition to other aspects of management of such children, especially in the resource-poor settings.

Anti-rotavirus protein reduces stool output in infants with diarrhea: a randomized placebo-controlled trial

BACKGROUND & AIMS

Rotavirus infection is a leading cause of morbidity and mortality in children younger than 5 years of age. Current treatment options are limited. We assessed the efficacy of a llama-derived, heavy-chain antibody fragment called anti-rotavirus protein (ARP1), in modifying the severity and duration of diarrhea in male infants with rotavirus infection.

METHODS

We performed a double-blind, placebo-controlled trial of 176 male infants (6-24 months old) with severe rotavirus-associated diarrhea at Dhaka Hospital, Bangladesh. The infants were randomly assigned to groups given oral ARP1 (15-30 mg/kg/day, n = 88) or placebo (maltodextrin, n = 88) for a maximum of 5 days. The primary outcomes were severity (stool output) and duration of diarrhea and fecal excretion of rotavirus. Secondary outcomes were intake of oral rehydration salt solution, severity of vomiting, and serum levels of rotavirus-specific IgA.

RESULTS

In infants with only rotavirus infection, total cumulative stool output was 305.47 g/kg body weight among those given placebo (n = 63) and 237.03 g/kg body weight among those given ARP1 (n = 61) (a difference of 68.44 g/kg body weight or 22.5%; 95% confidence interval: 18.27-118.59 g/kg body weight; P =.0079). There was a significant reduction in rate of stool output (g/kg/d) in the ARP1 group compared with the placebo group (61%; P = .002). ARP1 had no significant effect in infants with concomitant infections or on any other measured outcomes. No adverse events could be linked to ARP1.

CONCLUSIONS

In a placebo-controlled trial, ARP1 reduced stool output in male infants with severe rotavirus-associated diarrhea. Clinicaltrials.gov number: NCT01259765.

Pulmonary tuberculosis in severely-malnourished or HIV-infected children with pneumonia: a review

Presentation of pulmonary tuberculosis (PTB) as acute pneumonia in severely-malnourished and HIV-positive children has received very little attention, although this is very important in the management of pneumonia in children living in communities where TB is highly endemic. Our aim was to identify confirmed TB in children with acute pneumonia and HIV infection and/or severe acute malnutrition (SAM) (weight-for-length/height or weight-for-age z score <-3 of the WHO median, or presence of nutritional oedema). We conducted a literature search, using PubMed and Web of Science in April 2013 for the period from January 1974 through April 2013. We included only those studies that reported confirmed TB identified by acid fast bacilli (AFB) through smear microscopy, or by culture-positive specimens from children with acute pneumonia and SAM and/or HIV infection. The specimens were collected either from induced sputum (IS), or gastric lavage (GL), or broncho-alveolar lavage (BAL), or percutaneous lung aspirates (LA). Pneumonia was defined as the radiological evidence of lobar or patchy consolidation and/or clinical evidence of severe/ very severe pneumonia according to the WHO criteria of acute respiratory infection. A total of 17 studies met our search criteria but 6 were relevant for our review. Eleven studies were excluded as those did not assess the HIV status of the children or specify the nutritional status of the children with acute pneumonia and TB. We identified only 747 under-five children from the six relevant studies that determined a tubercular aetiology of acute pneumonia in children with SAM and/or positive HIV status. Three studies were reported from South Africa and one each from the Gambia, Ethiopia, and Thailand where 610, 90, 35, and 12 children were enrolled and 64 (10%), 23 (26%), 5 (14%), and 1 (8%) children were identified with active TB respectively, with a total of 93 (12%) children with active TB. Among 610 HIV-infected children in three studies from South Africa and 137 SAM children from other studies, 64 (10%) and 29 (21%) isolates of M. tuberculosis were identified respectively. Children from South Africa were infected with HIV without specification of their nutritional status whereas children from other countries had SAM but without indication of their HIV status. Our review of the existing data suggests that pulmonary tuberculosis may be more common than it is generally suspected in children with acute pneumonia and SAM, or HIV infection. Because of the scarcity of data, there is an urgent need to investigate PTB as one of the potential aetiologies of acute pneumonia in these children in a carefully-conducted larger study, especially outside Africa.

Clinical predictors and outcome of metabolic acidosis in under-five children admitted to an urban hospital in Bangladesh with diarrhea and pneumonia

Background

Clinical features of metabolic acidosis and pneumonia frequently overlap in young diarrheal children, resulting in differentiation from each other very difficult. However, there is no published data on the predictors of metabolic acidosis in diarrheal children also having pneumonia. Our objective was to evaluate clinical predictors of metabolic acidosis in under-five diarrheal children with radiological pneumonia, and their outcome.

Methods

We prospectively enrolled all under-five children (n = 164) admitted to the Special Care Ward (SCW) of the Dhaka Hospital of icddr, b between September and December 2007 with diarrhea and radiological pneumonia who also had their total serum carbon-dioxide estimated. We compared the clinical features and outcome of children with radiological pneumonia and diarrhea with (n = 98) and without metabolic acidosis (n = 66).

Results

Children with metabolic acidosis more often had higher case-fatality (16% vs. 5%, p = 0.039) compared to those without metabolic acidosis on admission. In logistic regression analysis, after adjusting for potential confounders such as age of the patient, fever on admission, and severe wasting, the independent predictors of metabolic acidosis in under-five diarrheal children having pneumonia were clinical dehydration (OR 3.57, 95% CI 1.62–7.89, p = 0.002), and low systolic blood pressure even after full rehydration (OR 1.02, 95% CI 1.01–1.04, p = 0.005). Proportions of children with cough, respiratory rate/minute, lower chest wall indrawing, nasal flaring, head nodding, grunting respiration, and cyanosis were comparable (p>0.05) among the groups.

Conclusion and Significance

Under-five diarrheal children with radiological pneumonia having metabolic acidosis had frequent fatal outcome than those without acidosis. Clinical dehydration and persistent systolic hypotension even after adequate rehydration were independent clinical predictors of metabolic acidosis among the children. However, metabolic acidosis in young diarrheal children had no impact on the diagnostic clinical features of radiological pneumonia which underscores the importance of early initiation of appropriate antibiotics to combat morbidity and deaths in such population.

Co-morbidity: exploring the clinical overlap between pneumonia and diarrhoea in a hospital in Dhaka, Bangladesh

BACKGROUND

There is limited information on risk factors for pneumonia and pneumonia-related deaths in children who also have diarrhoea.

AIM

To identify risk factors for the above in order to improve strategies for case management and to develop appropriate public health messages.

METHODS

All children under 5 years of age admitted to the Special Care Ward, Dhaka Hospital of the International Centre for Diarrhoeal Disease Research (ICDDR,B) from 1 September to 31 December 2007 were considered for enrollment if they also had diarrhoea. Of the 258 children with diarrhoea enrolled, those with (n=198) or without (n=60) WHO-defined pneumonia constituted the pneumonia and comparison groups, respectively. Among the 198 children with pneumonia, children who survived (n=174) were compared with those who died in hospital (n=24).

RESULTS

After adjusting for socio-demographic factors, including low levels of literacy of either parent, low household income, not having a window or exhaust fan in the kitchen, household smoking and over-crowding, children with pneumonia were more likely to sleep on a bare wooden-slatted or bamboo bed (OR 2·7, 95% CI 1·40-5·21, p = 0·003) than on other bedding, and were also more likely to have a parent/care-giver with poor knowledge of pneumonia (OR 1·94, 95% CI 1·02-3·70, p=0·043). Independent risk factors for death include severe underweight (OR 5·2, 95% CI 1·2-22·0, p=0·03), hypoxaemia (OR 17·5, 95% CI I 1·9-160·0, p=0·01), severe sepsis (OR 8·7, 95% CI I 1·8-41·5, p=0·007) and lobar consolidation (OR 11·9, 95% CI 2·3-61·6, p=0·003).

CONCLUSIONS

Increased public awareness of signs of pneumonia and severe sepsis in children under 5 is important to mitigate the risks of pneumonia and pneumonia-related deaths, and the importance of appropriate bedding for young children in reducing the risk of pneumonia needs to be addressed.

Predictors of death in under-five children with diarrhoea admitted to a critical care ward in an urban hospital in Bangladesh

AIM

To evaluate the clinical and laboratory predictors of death in hospitalized under-five children with diarrhoea.

METHODS

This is a prospective cohort study carried out in the Special Care Ward (SCW) of the Dhaka Hospital of the International Centre for Diarrhoeal Disease Research, Bangladesh (ICDDR,B), Dhaka, Bangladesh. All admitted diarrhoeal children of both sexes, aged 0-59 months, from September 2007 through December 2007 were enrolled. We compared and analysed factors among diarrhoeal children who died (n = 29) with those who survived (n = 229).

RESULTS

In logistic regression analysis, after adjusting for potential confounders (infusion of intravenous fluid and immature PMN), absent peripheral pulse even after complete rehydration (OR 10.9, 95% CI 2.1-56.8; p < 0.01), severe malnutrition (OR 7.9, 95% CI 1.8-34.8; p < 0.01), hypoxaemia (OR 8.5, 95% CI 1.0-75.0; p = 0.05), radiological lobar pneumonia (OR 17.8, 95% CI 3.7-84.5; p < 0.01) and hypernatraemia (OR 15.8, 95% CI 3.0-81.8; p < 0.01) were independently associated with deaths among diarrhoeal children admitted to SCW.

CONCLUSIONS

Thus, the absence of peripheral pulses even after full rehydration, severe malnutrition, hypoxaemia, lobar pneumonia and hypernatraemia are independent predictors of death among the under-five children with diarrhoea admitted to critical care ward of a resource-limited setting in Bangladesh.

Clinical predictors and outcome of hypoxaemia among under-five diarrhoeal children with or without pneumonia in an urban hospital, Dhaka, Bangladesh

OBJECTIVE

To explore the predictors and outcome of hypoxaemia in children under 5 years of age who were hospitalized for the management of diarrhoea in Dhaka, where comorbidities are common.

METHODS

In a prospective cohort study, we enrolled all children <5 years of age admitted to the special care ward (SCW) of the Dhaka Hospital of ICDDR,B from September to December 2007. Those who presented with hypoxaemia (SpO(2) < 90%) constituted the study group, and those without hypoxaemia formed the comparison group.

RESULTS

A total of 258 children were enrolled, all had diarrhoea. Of the total, 198 (77%) had pneumonia and 106 (41%) had severe malnutrition (<-3 Z-score of weight for age of the median of the National Centre for Health Statistics), 119 (46%) had hypoxaemia and 138 children did not have hypoxaemia at the time of admission. Children with hypoxaemia had a higher probability of a fatal outcome (21%vs. 4%; P < 0.001). Using logistic regression analysis, the independent predictors of hypoxaemia at the time of presentation were lower chest wall indrawing [OR 6.91, 95% confidence intervals (CI) 3.66-13.08, P < 0.001], nasal flaring (OR 3.22, 95% CI 1.45-7.17, P = 0.004) and severe sepsis (OR 4.48, 95% CI 1.62-12.42, P = 0.004).

CONCLUSION

In this seriously ill population of children with diarrhoea and comorbidities, hypoxaemia was associated with high case-fatality rates. Independent clinical predictors of hypoxaemia in this population, identifiable at the time of admission, were lower chest wall indrawing, nasal flaring and the clinical syndrome of severe sepsis.

Influences of dehydration on clinical features of radiological pneumonia in children attending an urban diarrhoea treatment centre in Bangladesh

BACKGROUND

As the signs of dehydration often overlap with those of pneumonia, it may be difficult for health workers in resource-poor settings to make a clinical diagnosis of pneumonia in children with dehydration. This issue has received very little attention.

AIM

To compare the clinical features of pneumonia in children with and without dehydration caused by diarrhoea.

METHODS

All children aged 2-59 months with diarrhoea and radiologically confirmed pneumonia admitted to the Special Care Ward (SCW) of Dhaka Hospital, ICDDR,B between September and December 2007 were enrolled for the study. Children with dehydration (67 cases) and those without (101 controls) were compared.

RESULTS

Cases presented less frequently with fast breathing (60% vs 88%, p<0.001) and lower chest-wall indrawing (67% vs 82%, p=0.035) than did controls. In logistic regression analysis, cases more often had severe malnutrition (OR 2.31, CI 1.06-5.02, p=0.035) and cyanosis (OR 19.05, CI 1.94-186.68, p=0.011) and were abnormally sleepy (OR 372, CI 1.71-8.08, p=0.001).

CONCLUSIONS

Fast breathing and lower chest-wall indrawing may be less reliable for the diagnosis of pneumonia in children with dehydration, especially when there is severe malnutrition.

Evidence of intra-familial transmission of Helicobacter pylori by PCR-based RAPD fingerprinting in Bangladesh

Helicobacter pylori is a genetically diverse bacterial species, which has facilitated adaptation to new hosts and persists worldwide. The main objective of this study was to explore intra-familial transmission of H. pylori in Bangladesh. We characterized H. pylori in 35 families including 138 family members using random amplified polymorphic DNA (RAPD) fingerprinting. Forty-six percent of H. pylori isolated from the mother shared a related genotype with strains isolated from their children. Twenty-nine percent of H. pylori isolates of the mother are related to the youngest children. Only 6% of the parents shared related genotype of H. pylori. These findings suggest that mother-to-child transmission occurs in early childhood and is the most probable route of transmission of H. pylori in Bangladesh.

Micronutrients and anaemia

Micronutrient deficiencies and anaemia remain as major health concerns for children in Bangladesh. Among the micronutrient interventions, supplementation with vitamin A to children aged less than five years has been the most successful, especially after distribution of vitamin A was combined with National Immunization Days. Although salt sold in Bangladesh is intended to contain iodine, much of the salt does not contain iodine, and iodine deficiency continues to be common. Anaemia similarly is common among all population groups and has shown no sign of improvement even when iron-supplementation programmes have been attempted. It appears that many other causes contribute to anaemia in addition to iron deficiency. Zinc deficiency is a key micronutrient deficiency and is covered in a separate paper because of its importance among new child-health interventions.

Use of antibodies in lymphocyte secretions for detection of subclinical tuberculosis infection in asymptomatic contacts

We have previously demonstrated that Mycobacterium bovis BCG-specific immunoglobulin G antibodies in lymphocyte secretions (ALS) can be employed as a marker for active tuberculosis (TB). We aimed to determine whether the ALS method allows detection of subclinical TB infection in asymptomatic individuals. A prospective study of family contacts (FCs) of patients with active TB and healthy controls was performed. Thirteen of 42 FCs had high ALS responses, including 6 FCs who subsequently developed active TB. No correlation was observed between the tuberculin skin test and the ALS responses in the FCs (r = 0.1, P = 0.23). Among patients with active TB, BCG-specific ALS responses steadily declined from the time of diagnosis through 6 months following antimycobacterial chemotherapy (P = 0.001). The ALS assay enabled detection of infection in exposed symptom-free contacts, who are at greater risk for developing active TB. The method may also allow discrimination between effective treatment of active infection and suboptimal response to therapy.

High prevalence of cagA and vacA seropositivity in asymptomatic Bangladeshi children with Helicobacter pylori infection

AIM

To evaluate the prevalence of antibodies against two major markers of virulence of Helicobacter pylori--cytotoxin-associated gene A (cagA) and the vacuolating cytotoxin gene (vacA)--among children in a peri-urban community of Bangladesh, and to evaluate Western blot (WB) assay for detection of H. pylori infection diagnosed by 13C urea breath test (UBT) in such children.

METHODS

One hundred and eighty-two children aged 18-60 mo, of the peri-urban community of Dhaka, were screened for H. pylori infection using UBT, and the serum samples were analysed for antibody against cagA and vacA by Western blot.

RESULTS

The overall prevalence of H. pylori infection by 13C-urea breath test was 80%. The seroprevalence of cagA with or without vacA, vacA with and without cagA, and both cagA and vacA were 82%, 82% and 81%, respectively. Among children with a positive UBT, 95% were seropositive for both cagA and vacA, indicating that the products of these genes are frequently co-expressed in H. pylori infection in this community. The sensitivity, specificity, positive and negative predictive value of the Western blot test for H. pylori infections, compared to UBT, were 94%, 68%, 92% and 76%, respectively.

CONCLUSION

Compared to UBT, Western blot test is reliable for the detection of H. pylori infection. The high seroprevalence of cagA- and vacA-positive virulent H. pylori strains in an asymptomatic paediatric population indicate that such strains are common in this population and may cause characteristic H. pylori infection in Bangladesh.

High prevalence of cagA and vacA seropositivity in asymptomatic Bangladeshi children with Helicobacter pylori infection

AIM

To evaluate the prevalence of antibodies against two major markers of virulence of Helicobacter pylori--cytotoxin-associated gene A (cagA) and the vacuolating cytotoxin gene (vacA)--among children in a peri-urban community of Bangladesh, and to evaluate Western blot (WB) assay for detection of H. pylori infection diagnosed by 13C urea breath test (UBT) in such children.

METHODS

One hundred and eighty-two children aged 18-60 mo, of the peri-urban community of Dhaka, were screened for H. pylori infection using UBT, and the serum samples were analysed for antibody against cagA and vacA by Western blot.

RESULTS

The overall prevalence of H. pylori infection by 13C-urea breath test was 80%. The seroprevalence of cagA with or without vacA, vacA with and without cagA, and both cagA and vacA were 82%, 82% and 81%, respectively. Among children with a positive UBT, 95% were seropositive for both cagA and vacA, indicating that the products of these genes are frequently co-expressed in H. pylori infection in this community. The sensitivity, specificity, positive and negative predictive value of the Western blot test for H. pylori infections, compared to UBT, were 94%, 68%, 92% and 76%, respectively.

CONCLUSION

Compared to UBT, Western blot test is reliable for the detection of H. pylori infection. The high seroprevalence of cagA- and vacA-positive virulent H. pylori strains in an asymptomatic paediatric population indicate that such strains are common in this population and may cause characteristic H. pylori infection in Bangladesh.

Partially hydrolysed guar gum supplemented comminuted chicken diet in persistent diarrhoea: a randomised controlled trial

BACKGROUND

Partially hydrolysed guar gum (Benefiber) added to a diet is fermented in the colon, producing short chain fatty acids, which improve intestinal function, including colonic salt and water absorption.

AIMS

To evaluate the effect of Benefiber supplemented comminuted chicken diet in the treatment of persistent diarrhoea.

METHODS

One hundred and sixteen children (aged 5-24 months), presenting to Dhaka Hospital with a history of watery diarrhoea for more than 14 days (persistent diarrhoea), were randomised to receive either: (1) comminuted chicken diet with Benefiber (study diet); or (2) comminuted chicken diet without Benefiber (control diet). The study period was seven days.

RESULTS

Of 116 children, 57 received the study diet and 59 received the control diet. Diarrhoea resolved in a greater number of children with the study than with the control diet (46/55 (84%) v 36/58 (62%); odds ratio 3.12, 95% CI 1.19 to 8.4). Survival analysis for the duration of diarrhoea also showed a reduced duration of diarrhoea in children receiving the study diet. There was also a trend in daily stool reduction in children receiving the study diet, significant on days 4-7.

CONCLUSION

Results show that Benefiber supplemented comminuted chicken diet enhances recovery of children with persistent diarrhoea, indicating its therapeutic potential.

Rapid diagnosis of active tuberculosis by detecting antibodies from lymphocyte secretions

In the present study, we investigated the tuberculosis (TB) diagnostic performance of an assay on the basis of detection of TB-specific antibodies from peripheral blood mononuclear cells (PBMCs), to determine whether antibodies in lymphocyte secretions obtained from PBMCs would better reflect active disease than antibodies in serum. PBMCs from patients with and without TB cultured in various concentrations for different times were assessed. Immunoglobulin G (IgG) specific for antigen (bacille Calmette-Guérin [BCG] vaccine and purified protein derivative [PPD]) was measured in lymphocyte secretions. Patients with active TB had higher BCG- or PPD-specific IgG antibody responses than patients without TB or healthy subjects (P=.001). This method can be used as a quick diagnostic aid to facilitate rapid detection of TB cases.

Apoptosis in acute shigellosis is associated with increased production of Fas/Fas ligand, perforin, caspase-1, and caspase-3 but reduced production of Bcl-2 and interleukin-2

Shigella dysenteriae type 1-induced apoptotic cell death in rectal tissues from patients infected with Shigella dysenteriae type 1 was studied by the terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling (TUNEL) technique and annexin V staining. Expression of proteins and cytokines participating in the apoptotic process (caspase-1, caspase-3, Fas [CD95], Fas ligand [Fas-L], perforin, granzyme A, Bax, WAF-1, Bcl-2, interleukin-2 [IL-2], IL-18, and granulocyte-macrophage colony-stimulating factor) in tissue in the acute and convalescent stages of dysentery was quantified at the single-cell level by in situ immunostaining. Apoptotic cell death in the lamina propria was markedly up-regulated at the acute stage (P < 0.05), where an increased number of necrotic cells were also seen. Phenotypic analysis of apoptotic cells revealed that 43% of T cells (CD3), 10% of granulocytes (CD15), and 5% of macrophages (CD56) underwent apoptosis. Increased activity of caspase-1 persisted in the rectum up to 1 month after onset. More-extensive expression of Fas, Fas-L, perforin, caspase-3, and IL-18, but not IL-2, at the acute stage than at the convalescent stage was observed. Increased expression of caspase-3 and IL-18 in tissues with severe inflammation compared to expression in those with mild inflammation was evident, implying a possible role in the perpetuation of inflammation. Significantly reduced cell death during convalescence was associated with a significant up-regulation of Bcl-2, Bax, and WAF-1 expression in the rectum compared to that in the acute phase of infection. Thus, induction of apoptosis at the local site in the early phase of S. dysenteriae type 1 infection was associated with a significant up-regulation of Fas/Fas-L and perforin and granzyme A expression and a down-regulation of Bcl-2 and IL-2, which promote cell survival.

Partially hydrolyzed guar gum-supplemented oral rehydration solution in the treatment of acute diarrhea in children

BACKGROUND

Partially hydrolyzed guar gum (Benefiber; Novartis Nutrition, Minneapolis, MN, U.S.A.) is fermented by colonic bacteria liberating short-chain fatty acids (SCFAs), which accelerate colonic absorption of salt and water. The purpose of this study was to evaluate the effect of Benefiber (BF)-supplemented World Health Organization Oral Rehydration Solution (WHO ORS) in the treatment of acute noncholera diarrhea in children.

METHODS

A double-blind, randomized, controlled clinical trial was performed at ICDDR,B in 150 male children aged 4 to 18 months who had watery diarrhea of less than 48 hours' duration. After admission, children were assigned to receive either WHO ORS or BF-supplemented WHO ORS until recovery. Major outcome measures, such as duration of diarrhea and amount of stool output, were compared between the treatment groups.

RESULTS

Patients receiving BF-supplemented WHO ORS had significantly reduced duration of diarrhea compared with the control group (mean +/- SD, 74 +/- 37 vs. 90 +/- 50 hours, P = 0.03). Survival analysis for duration of diarrhea also showed a reduction the BF-supplemented WHO ORS-treated group (P = 0.025, log rank test). There was also less stool output daily from days 2 through 7 in the patients treated with BF-supplemented WHO ORS compared with that in the children treated with WHO ORS; the reduction was significant on day 7 only.

CONCLUSION

Benefiber added to standard WHO ORS substantially reduces the duration of diarrhea and modestly reduced stool output in acute noncholera diarrhea in young children, indicating its potential as a new antidiarrheal therapy for acute diarrhea in children.

Urinary choloyl-PABA excretion in diagnosing small intestinal bacterial overgrowth: evaluation of a new noninvasive method

The synthetic substrate cholyl-PABA, developed by conjugating cholic acid with paraaminobenzoic acid, is hydrolyzed by the bacterial enzyme cholyl hydrolase to release free PABA. This study aimed to evaluate whether quantitating urinary excretion of PABA after oral administration of cholyl-PABA can detect small intestinal bacterial overgrowth. In the first phase, investigations were performed on 10 healthy volunteers to study the dynamics of urinary excretion of PABA and any adverse reactions after oral administration of 1.2 g of cholyl-PABA. Another 10 healthy volunteers and 25 adult patients with various gastrointestinal disorders participated in the second phase, where the urinary cholyl-PABA test was compared to the [14C]xylose breath test (XBT). The upper limit of normal levels of urinary PABA excretion at the end of 4 h was 1.1% of the administered dose of cholyl-PABA. The urinary PABA excretion after 4 hr [median (range), in percentage] in the XBT-positive group was 1.6 (0.6-35.0), which was significantly higher than those in the XBT-negative group [0.7 (0.4-1.8)] and the healthy controls [0.7 (0.2-1.1)]. The agreement between the XBT and the urinary cholyl-PABA test was 85.7% (P < 0.01). No adverse effect was noted. In conclusion, the urinary cholyl-PABA test offers a simple, safe, noninvasive, and rapid method for diagnosing small intestinal bacterial overgrowth and warrants further clinical evaluation.

Screening of patients with acute infectious diarrhoea: evaluation of clinical features, faecal microscopy, and faecal occult blood testing

BACKGROUND

For optimal management of acute infectious diarrhoeal diseases, it is necessary to utilize a screening process to distinguish between invasive and non-invasive diarrhoeas. The aim of this study was to compare the diagnostic utilities of clinical features, faecal microscopy (FM), and faecal occult blood testing (FOBT) in distinguishing invasive diarrhoeas from non-invasive ones.

METHODS

A total of 1008 patients with acute diarrhoea were evaluated. Rectal swabs were cultured for Salmonella, Shigella, and Vibrio species; rectal swabs from 109 of these patients were also examined for Campylobacter, enterotoxigenic Escherichia coli, and rotavirus species. Isolation of faecal enteropathogens served as the gold standard. FOBT was performed with a commercial modified guaiac test. Specificity, sensitivity, positive predictive value (PPV), negative predictive value (NPV), accuracy, and likelihood ratio were compared.

RESULTS

Among the 1008 patients 402 with a single identified enteropathogen were available for analysis. Invasive and non-invasive enteropathogens were isolated from 262 (65.2%) and 140 (34.8%) cases, respectively. The presence of visible blood in faeces was almost a pathognomonic sign of invasive diarrhoea but had poor sensitivity. Clinical features were useful but inadequate in differentiating patients with non-bloody diarrhoea (74% of patients) into invasive and non-invasive categories. The sensitivities, specificities, PPVs, and NPVs of FM and FOBT were 75%, 77%, 58%, 88%, and 85%, 68%, 53%, and 91%, respectively.

CONCLUSION

The presence of visible blood in faeces is a highly specific clinical feature of invasive diarrhoea but suffers from low sensitivity. In non-bloody diarrhoea FOBT is a valuable screening test and is comparable to FM, particularly when interpreted in the clinical context.

Intestinal immune responses in patients infected with enterotoxigenic Escherichia coli and in vaccinees

Immune responses against enterotoxigenic Escherichia coli (ETEC) were examined in Bangladeshi adults with naturally acquired disease and compared to responses in age-matched Bangladeshi volunteers who had been orally immunized with a vaccine consisting of inactivated ETEC bacteria expressing different colonization factor antigens (CFs) and the B subunit of cholera toxin. B-cell responses in duodenal biopsy samples, feces, intestinal washings, and blood were determined. Because most of the patients included in the study were infected with ETEC expressing CS5, immune responses to this CF were studied most extensively. Vaccinees and patients had comparable B-cell responses against this antigen in the duodenum: the median numbers of antibody-secreting cells (ASC) were 3,300 immunoglobulin A (IgA) ASC/10(7) mononuclear cells (MNC) in the patient group (n = 8) and 1,200 IgA ASC/10(7) MNC in the vaccinees (n = 13) (not a significant difference). Similarly, no statistically significant differences were seen in the levels of duodenal B cells directed against enterotoxin among vaccinees and patients. A comparison of the capacities of the various methods used to assess mucosal immune responses revealed a correlation between numbers of circulating B cells and antibody levels in saponin extracts of duodenal biopsy samples (r = 0.58; n = 13; P = 0.04) after vaccination. However, no correlation was seen between blood IgA ASC and duodenal IgA ASC after two doses of vaccine. Still, a correlation between numbers of CF-specific B cells in blood sampled from patients early during infection and numbers of duodenal B cells collected 1 week later was apparent (r = 0.70; n = 10; P = 0.03).

Helicobacter pylori infection in infants and children of Bangladesh

Helicobacter pylori is an important cause of chronic gastritis and plays important roles in the etiology of peptic ulcer disease, gastric cancer and non-ulcer dyspepsia. While H. pylori infections occur worldwide, the great majority of information is from the developed countries, and little is known about the epidemiology of H. pylori in the developing countries, particularly in children.

Helicobacter pylori colonization in infants and young children is not necessarily associated with diarrhoea

A cohort of 151 infants and young children aged 1-23 months from a poor peri-urban community of Bangladesh was studied to determine the relationship between Helicobacter pylori colonization and morbidity due to diarrhoea. A 13C urea breath test was performed to detect the presence of H. pylori. Children were followed up at home every alternate day for 6 months and diarrhoeal morbidity data were collected. Diarrhoeal morbidity was compared between H. pylori-positive and H. pylori-negative children. Sixty-eight (45 per cent) children were H. pylori positive and 83 (55 per cent) were H. pylori negative. During the first 1-month period following the breath test, three (4.4 per cent) H. pylori-positive and four (4.8 per cent) H. pylori-negative children had diarrhoea. Thirty-two (47 per cent) of the children in the positive group and 43 (52 per cent) in the negative group had one or more episodes of diarrhoea during the 6-month follow-up period. Median number of diarrhoeal episodes was 1.0 (range 1.0-4.0) in the H. pylori-positive children and 2.0 (range 1.0-5.0) in the H. pylori-negative children (p = 0.19). No significant difference was observed in the cumulative days with diarrhoea. The results of this study suggest that H. pylori colonization is not associated with diarrhoeal morbidity in infants and young children.

Astrovirus infection in association with acute, persistent and nosocomial diarrhea in Bangladesh

BACKGROUND

Diarrhea is an important public health concern in developing countries such as Bangladesh. Diarrhea in children that persists for 14 days or more occurs in 7% of patients in Bangladesh and frequently results in death. Astrovirus has been demonstrated as a cause of acute and nosocomial diarrhea and can be excreted for prolonged periods, yet its importance as a cause of diarrhea among children in a developing country like Bangladesh has not been investigated.

METHODS

We tested 629 stool specimens from patients with acute diarrhea, 153 from patients with persistent diarrhea, 175 specimens from 76 patients hospitalized for diarrhea who were sampled repeatedly to detect nosocomial infection and 428 from nonhospitalized healthy children (controls). All children enrolled in the study were <5 years of age. Astrovirus was detected by enzyme immunoassay and other enteropathogens were detected by standard techniques.

RESULTS

The detection of astrovirus increased significantly with the duration of diarrhea. Astrovirus was found in 23 (15%) specimens from patients with persistent diarrhea, 26 (4%) patients with acute diarrhea, but only 8 (2%) healthy controls. This trend remained when we limited our analysis to infants <12 months of age and to episodes in which astrovirus was the sole pathogen. Among patients with nosocomial diarrhea, 16% of postadmission specimens were positive for astrovirus when the admission specimen was negative.

CONCLUSION

The observation that astrovirus is detected more frequently with diarrhea of increasing duration suggests the need for further studies to determine whether astrovirus plays a causative role in persistent diarrhea or is a secondary agent.

Small bowel and fecal microbiology in children suffering from persistent diarrhea in Bangladesh

BACKGROUND

The etiology of persistent diarrhea in children is multifactorial. The objective of the current study was to ascertain the role of microorganisms in the etiology and pathogenesis of persistent diarrhea in a group of children in Bangladesh.

METHODS

Enteric pathogens and total aerobic microflora were studied in the duodenal aspirates of 100 children with persistent diarrhea and compared with those in aspirates of 30 children with acute diarrhea, and those in aspirates of 15 healthy control children. The enteric pathogens in the stools of these children and in stools of an additional 38 patients with persistent diarrhea and 12 with acute diarrhea were also studied.

RESULTS

Approximately two thirds of the patients with acute diarrhea and persistent diarrhea, and half of the control subjects had more than 10(5) organisms per milliliter of duodenal fluid. Significantly, more patients with persistent diarrhea had a greater variety of flora than did patients with acute diarrhea and control subjects. The predominant organisms in patients with acute diarrhea and in those with persistent diarrhea were Gram-negative rods, whereas those in control subjects were Gram-positive cocci. Significantly more acute diarrhea patients and persistent diarrhea patients had enteric pathogens isolated from stool than did control subjects. Diarrheagenic Escherichia coli, as a whole, were present in significantly more persistent diarrhea patients than in acute diarrhea patients and control subjects. Among diarrheagenic E. coli, enteroaggregative E. coli were significantly associated only with persistent diarrhea. Other organisms significantly associated with persistent diarrhea were Aeromonas spp. and Klebsiella spp. Some patients in the acute diarrhea and the persistent diarrhea groups had the same pathogens isolated from both the duodenal fluid and stool.

CONCLUSIONS

In accordance with results of other studies, an association between enteroaggregative E. coli and persistent diarrhea was found in the present study. This suggests that therapy directed against enteroaggregative E. coli can be evaluated for management of some cases of persistent diarrhea.

Epidemiological features of Helicobacter pylori infection in developing countries

Helicobacter pylori infection has a worldwide distribution, and it has distinct epidemiological features in developing countries. In contrast to that in developed countries, H. pylori infection in developing countries seems to be nearly universal, beginning in early childhood. Children become infected in the first few months of life; in some communities as many as 50% of the children are infected by the age of 5 years, and up to 90% are infected by the time they reach adulthood. In some developing countries with improvements in industrialization, socioeconomic conditions, and hygiene, infection rates are lower. The incidence of H. pylori infection, determined indirectly, also suggests a rate several times higher than that in developed countries. Marked differences in H. pylori seroprevalence have been observed between various ethnic and racial groups. Although the mode of transmission of H. pylori remains uncertain, evidence suggests person-to-person transmission occurs.

Helicobacter pylori: prevalence, transmission, and serum pepsinogen II concentrations in children of a poor periurban community in Bangladesh

The aim of this study was to determine the age-specific prevalence of Helicobacter pylori infection in infants and children aged 1-99 months from a poor periurban community in Bangladesh. We also examined the frequency of infection among infants and their 53 immediate family members and evaluated the relationship between infection and fasting serum group II pepsinogen (pepsinogen II) concentration in 76 children. Sixty-one percent of 1-3 month-old infants tested positive for H. pylori; this rate declined steadily to 33% in children aged 10-15 months and then increased to 84% in children aged 5-8 years. The H. pylori infection rate was 2.5 times higher in children with illiterate mothers. No difference in infection rate was detected among the family contacts of infected vs. noninfected infants. H. pylori-infected children had significantly higher serum pepsinogen II concentrations than did noninfected children (P < .001). We conclude that infection with H. pylori is highly prevalent and occurs at an early age. An environmental factor or factors, rather than or in addition to intrafamilial spread of this infection, are important in poor communities of Bangladesh. The higher levels of serum pepsinogen II in H. pylori-positive children might indicate the presence of gastritis in such asymptomatic children.

Noninvasive assessment of gastric acid secretion in man. Application of electrical impedance tomography (EIT)

Electrical impedance tomography (EIT) is a tubeless technique that generates tomographic images of gastric resistivity. We investigated the application of EIT to measure gastric acid secretion. Nineteen normal subjects underwent a standard intubation test. Basal acid output (BAO) and stimulated acid output (SAO) (millimoles per hour) were measured before and after pentagastrin, respectively. On a different day, EIT was performed before (basal) and after pentagastrin (stimulated). The changes in impedance over time were measured and the area under the curve (AUC) was calculated. Both the tests were repeated in 13 subjects after omeprazole treatment. As in the intubation test, there was the expected increase in AUC value after pentagastrin (basal vs stimulated; 1.2 +/- 2.8 vs 731 +/- 297, P < 0.0001). A significant fall in acid output and AUC following omeprazole pretreatment was observed (without vs with omeprazole; 20.5 +/- 5.7 vs 0.03 +/- 0.06, P < 0.0001 for intubation test and 731 +/- 297 vs 44 +/- 172, P < 0.0001 for EIT). There was a significant correlation between SAO and the delta AUC with (r = 0.65 P < 0.001) or without (r = 0.95, P < 0.001) omeprazole and in all the experiments (r = 0.87, P < 0.001). This study demonstrates the predictable change of gastric impedance and may be useful as a noninvasive test for measuring gastric acid secretion.

Quantitative assessment of IgG and IgA subclass producing cells in rectal mucosa during shigellosis

AIMS

To assess quantitatively both the morphological changes in the rectal mucosa and the changes in the relative frequency of IgA and IgG subclass producing cells found in the rectal mucosa during the acute phase of shigellosis and at convalescence.

METHODS

Rectal biopsies from 25 Shigella dysenteriae 1 infected patients, 10 Shigella flexneri infected patients, and 40 uninfected controls were studied. Morphological changes in the mucosa were graded. The frequency of IgA and IgG subclass producing cells was assessed. In addition, immunostaining for secretory component in epithelial cells was analysed.

RESULTS

Using morphological grading, 20% of the 35 patients studied had advanced inflammation (grade 3) in the acute phase of the disease. At convalescence, grade 1 inflammation was seen in 37% of the patients and in 10% of the controls. In the acute phase, as well as at convalescence, the number of IgA1, IgA2, and IgG2 positive cells was significantly higher than in the controls. The results were related to the histopathological degree of inflammation.

CONCLUSIONS

In shigellosis, there is evidence for a prolonged humoral response residing in the mucosa long after the clinical symptoms have resolved, suggesting that shigellosis induces persisting mucosal humoral immune and inflammatory responses, remaining at least until 30 days after the infection.

In situ characterization of inflammatory responses in the rectal mucosae of patients with shigellosis

Shigella species cause bacillary dysentery in humans by invading epithelial cells of the colonic mucosa leading to colonic epithelial cell destruction and inflammation. For further analysis of local gut inflammation, morphological changes and the potential involvement of mediators in regulatory mechanisms of cell activation and cell proliferation were studied immunohistochemically in rectal mucosal biopsies taken from patients during the acute phase of shigellosis and at convalescence. Rectal biopsies from 25 Shigella dysenteriae-1 and 10 Shigella flexneri-infected patients and from 40 controls were studied. The frequencies of proliferative cells (Ki67-positive cells), p53-immunostaining cells, and cells coexpressing Ki67 with CD3 or with p53 were analyzed. Immunostaining for the inducible nitric oxide synthase (iNOS) and the endothelial NOS was assessed. In addition, the frequencies of apoptotic cells and CD68+ cells that engulf apoptotic cells were assessed. By morphological grading, 20% of the patients had advanced inflammation (grade 3) in the acute phase; mild inflammation (grade 1) was seen in 37% of the patients at convalescence as well as in 10% of the controls. The findings in the present study suggest that in the acute phase of shigellosis inflammation is characterized by increased cell turnover in the lamina propria (LP) and the epithelium, increased iNOS expression in the surface epithelium, and apoptosis, which seems to be associated with LP macrophages. The findings also suggest that neither p53 nor iNOS are important factors for the induction of apoptosis in shigellosis. Expression of p53 may be related to early cell activation in crypt epithelium. Moreover, there is an indication of an active, low-level inflammatory process at convalescence. The results thus indicate that Shigella-induced inflammation is associated with a complex series of cellular reactions in the rectal gut mucosa which persist long after clinical symptoms have resolved.

Helicobacter pylori infection in the young in Bangladesh: prevalence, socioeconomic and nutritional aspects

BACKGROUND

The gastric acid barrier, an important host defence against small bowel infection, may be compromised by infection with Helicobacter pylori. In developing countries, H. pylori infection occurs early in life and prevalence of hypochlorhydria is high particularly in the malnourished, which may predispose a child to repeated gastrointestinal infection and diarrhoea. Diarrhoea being a leading cause of childhood mortality and morbidity in developing countries, we investigated the prevalence of H. pylori infection in children in a poor Bangladeshi community and explored its association with socioeconomic and nutritional status.

METHODS

The study was conducted in a poor periurban community among 469 children aged 1-99 months. Parents were interviewed using a questionnaire. To detect active infection with H. pylori a 13C-urea breath test was performed and weight was recorded on a beam balance with a sensitivity of 20 g.

RESULTS

In all, 61% of 36 infants aged 1-3 months were positive for H. pylori; this rate dropped steadily with increasing age and was 33% in 10-15 month old children and then rose to 84% in 6-9 year olds. Overall H. pylori infection had no association with nutritional state of the child, or family income but the infection rate was 2.5 times higher in children of mothers with no schooling.

CONCLUSIONS

The H. pylori infection rate is very high in early infancy in a poor periurban community of Bangladesh. The reason for a drop in the infection rate in late infancy is unclear but could be due to initial clearance of the infection by the body's defence mechanisms but with possible alteration of the gastric mucosa which sustains infection. Maternal education may be protective and may operate through some unidentified proximate behavioural determinants. The rate of H. pylori infection in infants and young children may predispose them to repeated gastrointestinal infection and diarrhoea.

Prevalence of Helicobacter pylori infection in infants and family contacts in a poor Bangladesh community

Although H. pylori is well established as an etiological agent of type B gastritis and a predisposing factor for peptic ulcer, knowledge about its transmission is unclear. In this study we examined the prevalence of H. pylori infection in the family members of index infants infected with this organism as indicated by positive [13C]-urea breath test (UBT). We performed UBT among family members of 15 predominantly breastfed infants, eight with and seven without H. pylori infection. Infection rates were 82% and 91% in family contacts of the infected and noninfected infants respectively, the average infection rate being 85%, which is rated to be high. There was no difference in infection rates among the parents of the infected and noninfected infants. Fifty percent and 70% families belonging to infected and noninfected infants, respectively, were found to have all members infected with H. pylori. No evidence of sex predilection of infection was found. We conclude that in communities with high prevalence of H. pylori infection, there is almost an equal infection rate among the family contacts of infected and noninfected infants, suggesting that environmental factors may be more important than intrafamilial transmission.

Down-regulation of gamma interferon, tumor necrosis factor type I, interleukin 1 (IL-1) type I, IL-3, IL-4, and transforming growth factor beta type I receptors at the local site during the acute phase of Shigella infection

An immunohistochemical technique was used to examine whether there was a colocalization of cytokine-specific receptors with cytokine-expressing cells. We have previously shown that there is extensive cytokine production and secretion in the rectal mucosa in shigellosis (interleukin 1 alpha [IL-1 alpha], IL-1 beta, IL-1ra, IL-4, IL-6, IL-8, IL-10, tumor necrosis factor alpha [TNF-alpha], TNF-beta, gamma interferon, granulocyte-macrophage colony-stimulating factor, and transforming growth factor beta [TGF-beta]) (R. Raqib, A. A. Lindberg, B. Wretlind, P. K. Bardhan, U. Andersson, and J. Andersson, Infect. Immun. 63:289-296, 1995; R. Raqib, B. Wretlind, J. Andersson, and A. A. Lindberg, J. Infect. Dis. 171:376-384, 1995). Kinetics for receptor expression was compared with that for cytokine synthesis in the inflamed rectal mucosa from Shigella-infected patients during acute (2 to 6 days after onset of diarrhea) and convalescent (30 to 40 days after onset) stages. Quantification of receptor expression was assessed by computer-assisted analysis of video microscopic images. A selective down-regulation of the receptors for gamma interferon, tumor necrosis factor (TNF receptor [TNFR] type I), IL-1 (IL-1 receptor [IL-1R] types I and type II), IL-3, IL-4, and TGF-beta (TGF-beta receptor type I) was observed at the onset of the disease, with a gradual reappearance during the convalescent stage. However, IL-2R, IL-6R, granulocyte-macrophage colony-stimulating factor receptor, TNFR type II, and TGF-beta receptor type II showed no change in expression during the study period and were comparable to controls. Cytokine receptors were predominantly located to the epithelial layer of the mucosal surface and crypts, with variable expression patterns in the lamina propria. A time-dependent kinetic curve was seen for the soluble IL-2R (sIL-2R), sIL-6R, and sTNFR types I and type II shed in stool at the acute stage similar to that observed for cytokine secretion in stool but at four- to six-times-lower concentration. In contrast, soluble receptor levels in plasma were 100-fold higher than the cytokine levels. The results suggest a dissociation in immune regulation between cytokine production and cytokine receptor expression. The down-regulation of the receptors in acute shigellosis was probably a consequence of cytokine-induced internalization and shedding of the receptors during signal transduction as well as due to programmed regulatory roles played by cytokines and the bacterial antigens.

Shigella infection induces cellular activation of T and B cells and distinct species-related changes in peripheral blood lymphocyte subsets during the course of the disease

Immunophenotypic changes in peripheral blood lymphocytes (T, B, and NK cells) in patients during shigellosis was characterized by using triple-color flow cytometry. Eleven Shigella dysenteriae 1-infected adult patients (SDIP), 11 Shigella flexneri-infected adult patients (SFIP), 15 age- and sex-matched healthy controls from Bangladesh (C-B), and 15 healthy volunteers from Sweden (V-S) were studied. In SDIP and SFIP, a significant increase in the CD45RO+ cells in both CD4+ and CD8+ T cells were seen. We found evidence for sequential T-cell activation, as shown by increased proportions of CD25 and CD4+ cells; HLA-DR and CD38 on CD8+ cells, and CD54 on CD4+ and CD8+ cells. We found differences in the lymphocyte activation and subset patterns related to the infecting Shigella species. Thus, a decrease in CD45 expression was seen in SFIP; this decrease progressed further during the disease. The proportions of NK cells (CD56+ cells) and CD3- CD8+ cells out of the total CD8+ cells were increased in SFIP but not in SDIP. The CD3+ CD8+ CD57+ T-cell subset was significantly lower in SDIP than in C-B. The proportion of B-lymphocyte-expressing activation markers CD80 and CD23 was higher in patients than in C-B. There was a significant increase in the proportion of CD4+ T cells and a significant decrease in the percentages of total B cells, the CD3+ CD8+ CD57+ T-cell subset, and the CD56+ CD16+ NK-cell subset for V-S compared with C-B. Our results indicate that distinct subset changes and activation patterns are elicited in SDIP compared with SFIP and also that the degree of activation is related to disease severity. In addition, a common sequence of cell activation was seen during the disease course. The difference in the subset patterns seen in C-B and V-S may be related to differences in the levels or spectra of infectious agents in the environment.

Trimethoprim-sulphamethoxazole in the treatment of persistent diarrhoea: a double blind placebo controlled clinical trial

The efficacy of an absorbable antimicrobial agent trimethoprim-sulphamethoxazole (TMP-SMX) in the management of children with persistent diarrhoea was evaluated in a double blind, randomised, and placebo controlled trial. Of the 55 patients studied, 28 received TMP-SMX, and 27 received placebo. A trend in stool weight reduction was observed from the third day after the drug was started, and the reduction was statistically significant on day 6 and day 7. However, the difference in total stool output (g/kg) up to day 7 was not significantly different between the two groups. The proportion of children whose diarrhoea resolved by day 7 (therapeutic success) was significantly more in the treatment group compared with the placebo group (23 v 15). Additionally, mean duration of diarrhoea in the group that received TMP-SMX was less compared with the placebo group (6.0 v 8.3 days); this difference, however, was not significant. Hospital infection (probably nosocomial infection) was significantly less in the TMP-SMX treated group (1 v 10). The results of our study indicate that TMP-SMX has a clinical benefit in respect of reducing the stool output, and higher recovery rate within seven days of treatment. In addition, it prevented possible hospital acquired infection.

Plasma secretin determination as a test of gastric acid secretion: effect of a marker perfusion technique on validation

OBJECTIVE

To examine whether plasma secretin levels can be used as a diagnostic measure of gastric acid output.

METHODS

A marker perfusion technique was used to quantify gastric acid output. Blood samples were drawn for secretin radioimmunoassay at specified intervals before and after pentagastrin stimulation in six healthy volunteers and six patients suspected of having abnormal gastric acid secretion.

RESULTS

Linear relationships were found between integrated secretin response and maximal acid output as well as between peak acid output and acid output at 2 h (P < 0.01). Similar correlations were also observed with secretin levels 52, 60 and 68 min after pentagastrin stimulation. Discrimination between low, average and high gastric acid secretors was possible at 52 and 60 min after stimulation. Plasma secretin did not increase after pentagastrin stimulation in the 12 subjects when acid was continually aspirated, nor did correction for gastric acid loss improve the correlation or discrimination.

CONCLUSION

One or two measurements of plasma secretin about 1 h after pentagastrin administration may provide a useful quantitative estimate of gastric secretory capacity for epidemiological or clinical purposes.

Persistence of local cytokine production in shigellosis in acute and convalescent stages

Shigella infection is accompanied by an intestinal activation of epithelial cells, T cells, and macrophages within the inflamed colonic mucosa. A prospective study was carried out to elucidate the cytokine pattern in Shigella infection linked to development of immunity and eradication of bacteria from the local site and also to correlate the cytokine profile with histological severity. An indirect immunohistochemical technique was used to determine the production and localization of various cytokines at the single-cell level in cryopreserved rectal biopsies from 24 patients with either Shigella dysenteriae type 1 (n = 18) or Shigella flexneri (n = 6) infection. The histopathological profile included presence of chronic inflammatory cells with or without neutrophils and microulcers in the lamina propria, crypt distortion, branching, and less frequently crypt abscesses. Patients had significantly higher (P < 0.005) numbers of cytokine producing cells for all of the cytokines studied, interleukin-1 alpha (IL-1 alpha), IL-1 beta, IL-1ra, tumor necrosis factor alpha (TNF-alpha), IL-6, IL-8, IL-4, IL-10, gamma interferon, TNF-beta, and transforming growth factor beta 1-3, in the biopsies than the healthy controls (n = 13). The cytokine production profile during the study period was dominated by IL-1 beta, transforming growth factor beta 1-3, IL-4, and IL-10. Significantly increased frequencies of cytokine-producing cells (P < 0.05) were observed for IL-1, IL-6, gamma interferon, and TNF-alpha in biopsies with severe inflammation in comparison with those with mild inflammation. During the acute stage of the disease, 20 of 24 patients exhibited acute inflammation in the rectal biopsies and the cellular infiltration was still extensive 30 days after the onset of diarrhea, although the disease was clinically resolved. In accordance with the histological findings, cytokine production was also upregulated during the convalescent phase; there was no significant difference (P > 0.05) in the incidence of cytokine-producing cells between acute (2 to 8 days after the onset of diarrhea) and convalescent (30 days after onset) stages.

Comparative trial of five antimicrobial compounds in the treatment of cholera in adults

To compare the efficacy of ciprofloxacin, erythromycin, nalidixic acid and pivmecillinam in the treatment of tetracycline-resistant strains of Vibrio cholerae O1 in adults, a randomized, open, clinical trial was conducted. A tetracycline group was used for comparison. Seventy-five adult men infected with V. cholerae O1 were randomly assigned to receive either 400 mg pivmecillinam or 500 mg of one of each of the other drugs. Ciprofloxacin was given every 12 h and the others every 6 h for 3 d. The mean total stool volume per kg was 155 mL for the ciprofloxacin group, 212 mL for the erythromycin and pivmecillinam groups, 246 mL for nalidixic acid, and 293 mL for tetracycline. The difference between ciprofloxacin and tetracycline was significant (P = 0.045). After 72 h, diarrhoea had stopped in 14 patients (93%) in the ciprofloxacin group and 12 (80%) in the erythromycin group, compared to 5 (42%) of those receiving tetracycline (P = 0.006 and 0.049, respectively). Bacteriological clearance was 100% at 24 h in patients treated with ciprofloxacin compared to 20% and 8.3% (P < 0.001 for both comparisons) in the erythromycin and tetracycline groups. Ciprofloxacin in conjunction with appropriate fluid therapy was the most effective treatment for cholera in adults; erythromycin was the next best.

Octreotide (SMS 201-995) as an antisecretory agent in cholera toxin & bile acid induced intestinal secretion in an in vivo animal study

The effect of Octreotide (SMS 201-995), synthetic somatostatin analogue on small intestinal and colonic fluid secretion induced respectively by cholera toxin (CT) and deoxycholic acid (DCA) was investigated in rabbits using in vivo isolated loops. After exposure to CT and DCA, marked fluid accumulation was observed in the small intestinal and colonic loops, along with elevation of jejunal and colonic mucosal cyclic AMP concentrations. Octreotide inhibited CT and DCA induced small intestinal and colonic secretion, dose-dependently. This anti-secretory effect was observed after both intramuscular and oral administration of octreotide. In contrast, octreotide did not affect the elevated mucosal cyclic AMP concentrations. These results suggest that octreotide inhibits CT and DCA induced intestinal secretion, and this anti-secretory effect is produced by affecting processes beyond cyclic AMP formation.

Immunopathological patterns in the rectal mucosa of patients with shigellosis: expression of HLA-DR antigens and T-lymphocyte subsets

Expression of HLA-DR antigens and infiltration of T-lymphocyte subsets (CD4, CD8), cell activation marker (CD25), B cells (CD20), macrophages (CD68 and Ber-Mac 3) and natural killer cells (CD56) in the rectal mucosa of patients with bacillary dysentery and in healthy controls were studied in an effort to interpret the immunopathological changes taking place in the rectal mucosa during the acute phase of shigellosis. The epithelium of the rectal mucosa from 21 of 32 patients was HLA-DR+. Conventional histology showed acute inflammation in 16 of these patients, chronic inflammation in 3, and in 2 histology was normal. In 7 of 20 controls the epithelium was HLA-DR+; 4 of these 7 were found to suffer from chronic inflammation, whilst in 3 the mucosa was normal. The number of HLA-DR+ intraepithelial lymphocytes in biopsies from patients with Shigella infection was significantly higher (p = 0.005) than in controls. The infiltration of CD8+ cells in the surface epithelium and in the lamina propria, and of CD4+ cells in the lamina propria alone, was significantly higher (p < 0.001) in patients than in controls. The results demonstrate that infiltration of T cells with suppressor/cytotoxic or helper/inducer phenotype in the epithelium and in the lamina propria in Shigella-infected patients may be related to the induction of HLA-DR expression in non-lymphoid cells during acute Shigella infection.

Pathology of shigellosis and its complications

One hundred and thirty-three colonic biopsies of proven cases of Shigella colitis were examined and post-mortem examinations were carried out on 29 fatal cases at the International Centre for Diarrhoeal Disease Research, Bangladesh (ICDDR, B) hospital between 1988 and 1992. The distribution of pathological lesions and the spectrum of histopathological changes in the intestinal tract of these patients, and the features of intestinal and extra-intestinal complications of shigellosis are presented. Septicaemia, hyponatraemia, hypokalaemia and hypoglycaemia were present in a high percentage of these cases. All but two patients were malnorished at the time of autopsy. Shigellosis patients rapidly became hypoproteinaemic and were susceptible to other infections including opportunistic infections. Mortality amongst shigellosis patients admitted to our hospital continues to be high in spite of adequate antibiotic and supportive therapy.

Effects of tropisetron, a 5-hydroxytryptamine type 3 receptor blocker, on intestinal secretion induced by cholera toxin or deoxycholic acid in rabbits in vivo

It has been suggested that 5-hydroxytryptamine is involved in the pathogenesis of various intestinal hypersecretory states including cholera. In this study, the effect of tropisetron (ICS 205-930), a specific 5-hydroxytryptamine type-3 receptor blocker, on jejunal and colonic fluid secretion induced respectively by cholera toxin and deoxycholic acid was investigated in rabbits using isolated loops of intestine in vivo. Marked fluid accumulation in both the jejunal and colonic loops was observed after exposure to cholera toxin and deoxycholic acid respectively. Elevation of jejunal and colonic mucosal cyclic adenosine monophosphate concentrations was also noted. Intraperitoneal administration of tropisetron dose-dependent inhibited jejunal secretion induced by cholera toxin. In contrast, no significant anti-secretory effect of tropisetron was observed against colonic secretion induced by deoxycholic acid. Tropisetron did not affect elevated mucosal cyclic adenosine monophosphate concentrations. The inhibitory effect of tropisetron on intestinal secretion induced by cholera toxin, which was independent of cyclic adenosine monophosphate formation, suggests that 5-hydroxytryptamine plays an important role in this type of secretion.