Changing trends in the prevalence of Shigella species: emergence of multi-drug resistant Shigella sonnei biotype g in Bangladesh.

Shigellosis, caused by Shigella species, is a major public health problem in Bangladesh. To determine the prevalence and distribution of different Shigella species, we analyzed 10,827 Shigella isolates from patients between 2001 and 2011. S. flexneri was the predominant species isolated throughout the period. However, the prevalence of S. flexneri decreased from 65.7% in 2001 to 47% in 2011, whereas the prevalence of S. sonnei increased from 7.2% in 2001 to 25% in 2011. S. boydii and S. dysenteriae accounted for 17.3% and 7.7% of the isolates respectively throughout the period. Of 200 randomly selected S. sonnei isolates for extensive characterization, biotype g strains were predominant (95%) followed by biotype a (5%). Resistance to commonly used antibiotics including trimethoprim-sulfamethoxazole, nalidixic acid, ciprofloxacin, mecillinam and ampicillin was 89.5%, 86.5%, 17%, 10.5%, and 9.5%, respectively. All isolates were susceptible to ceftriaxone, cefotaxime, ceftazidime and imipenem. Ninety-eight percent of the strains had integrons belonging to class 1, 2 or both. The class 1 integron contained only dfrA5 gene, whereas among class 2 integron, 16% contained dhfrAI-sat1-aadA1-orfX gene cassettes and 84% harbored dhfrA1-sat2 gene cassettes. Plasmids of ∼5, ∼1.8 and ∼1.4 MDa in size were found in 92% of the strains, whereas only 33% of the strains carried the 120 MDa plasmid. PFGE analysis showed that strains having different integron patterns belonged to different clusters. These results show a changing trend in the prevalence of Shigella species with the emergence of multidrug resistant S. sonnei. Although S. flexneri continues to be the predominant species albeit with reduced prevalence, S. sonnei has emerged as the second most prevalent species replacing the earlier dominance by S. boydii and S. dysenteriae in Bangladesh.

Clinical signs of radiologic pneumonia in under-five hypokalemic diarrheal children admitted to an urban hospital in bangladesh.

BACKGROUND: Clinical signs of pneumonia are often veiled in under-five diarrheal children presenting with hypokalemia, making clinical diagnosis of pneumonia very difficult in such population. However, there is no published report that describes the influences of hypokalemia on the clinical signs of pneumonia in diarrheal children. Our objective was to assess the influences of hypokalemia, and their outcome in such children. METHODS: We prospectively enrolled all under-five diarrheal children (n = 180) admitted to the Special Care Ward of the Dhaka Hospital of icddr,b from September-December 2007 with radiological pneumonia who also had their serum potassium estimated. We compared the clinical features and outcome of the diarrheal children having pneumonia with (cases = 55) and without hypokalemia (controls = 125). RESULTS: The case-fatality among the cases was 2 times higher compared to the controls, but the difference was not statistically significant (p = 0.202). In logistic regression analysis, after adjusting for potential confounders such as age of the patient, clinical dehydration, severe wasting, abnormally sleepy, lower chest wall in-drawing, nasal flaring and inability to drink on admission, under-five diarrheal children with pneumonia who presented with nutritional edema had 3 times more risk to have hypokalemia compared to those without nutritional edema (OR = 2.76, 95% CI = 1.01-7.51) and these hypokalemic children were 64% less likely to present with fast breathing (OR = 0.36, 95% CI = 0.17-0.74). CONCLUSION AND SIGNIFICANCE: The results of our analysis are simple but may have great public health implications and underscore the importance of diligent assessment for pneumonia in under-five diarrheal children having risk of hypokalemia as in children with nutritional edema even in absence of fast breathing, a useful sign of pneumonia. This may help for early initiation of first dose of parental antibiotics along with potassium supplementation before referral to tertiary hospitals by health workers to combat probability of deaths in such population especially in resource limited settings.

Risk factors for severe cholera among children under five in rural and urban Bangladesh, 2000-2008: a hospital-based surveillance study.

BACKGROUND: Children under five bear the largest cholera burden. We therefore sought to identify modifiable risk factors among Bangladeshi children. METHODOLOGY/PRINCIPAL FINDINGS: We used multivariate Poisson regression to assess risk factors for severe cholera among diarrheal patients presenting at hospitals in Matlab (rural) and Dhaka (urban), Bangladesh. Risk increased with age. Compared to those under one, rural and urban four-year-olds had adjusted risk ratios (aRR) of 4.17 (95% confidence interval (CI) 2.43-7.15) and 6.32 (95% CI: 4.63-8.63), respectively. Breastfeeding halved the risk in both rural (aRR = 0.49, 95% CI: 0.35-0.67) and urban (aRR = 0.51, 95% CI: 0.41-0.62) settings. Rural children's risk decreased with maternal education (P-trend: <0.001) and increased among those with a family member with diarrhea in the past week (aRR = 1.61, 95% CI: 1.22-2.14) and those with prior vitamin A supplementation (aRR = 1.65, 95% CI: 1.12-2.43). Urban children whose mothers daily (aRR = 0.41, 95% CI: 0.21-0.79) or occasionally (aRR = 0.55, 95% CI: 0.36-0.84) read a newspaper experienced reduced risk. Urban children from households with incomes between 34-84 USD/month had a 30% increased risk compared to those from households with incomes >84 USD/month. CONCLUSION/SIGNIFICANCE: Increasing age, lower socioeconomic status, and lack of breastfeeding are key correlates of increased risk for cholera hospitalization among those under five in rural and urban Bangladesh. In addition, having a family member with diarrhea in the past week was associated with increased risk among rural children. Continued attention should be directed to the promotion of breastfeeding. Further research is needed to elucidate the relationship between maternal education and cholera risk. Renewed research regarding the use of chemoprophylaxis among family members of cholera cases may be warranted in rural endemic settings.

Effect of weekly zinc supplements on incidence of pneumonia and diarrhoea in children younger than 2 years in an urban, low-income population in Bangladesh: randomised controlled trial.

BACKGROUND: Pneumonia and diarrhoea cause much morbidity and mortality in children younger than 5 years. Most deaths occur during infancy and in developing countries. Daily regimens of zinc have been reported to prevent acute lower respiratory tract infection and diarrhoea, and to reduce child mortality. We aimed to examine whether giving zinc weekly could prevent clinical pneumonia and diarrhoea in children younger than 2 years. METHODS: 1665 poor, urban children aged 60 days to 12 months were randomly assigned zinc (70 mg) or placebo orally once weekly for 12 months. Children were assessed every week by field research assistants. Our primary outcomes were the rate of pneumonia and diarrhoea. The rates of other respiratory tract infections were the secondary outcomes. Growth, final serum copper, and final haemoglobin were also measured. Analysis was by intention to treat. FINDINGS: 34 children were excluded before random assignment to treatment group because they had tuberculosis. 809 children were assigned zinc, and 812 placebo. After treatment assignment, 103 children in the treatment group and 44 in the control group withdrew. There were significantly fewer incidents of pneumonia in the zinc group than the control group (199 vs 286; relative risk 0.83, 95% CI 0.73-0.95), and a small but significant effect on incidence of diarrhoea (1881 cases vs 2407; 0.94, 0.88-0.99). There were two deaths in the zinc group and 14 in the placebo group (p=0.013). There were no pneumonia-related deaths in the zinc group, but ten in the placebo group (p=0.013). The zinc group had a small gain in height, but not weight at 10 months compared with the placebo group. Serum copper and haemoglobin concentrations were not adversely affected after 10 months of zinc supplementation. INTERPRETATION: 70 mg of zinc weekly reduces pneumonia and mortality in young children. However, compliance with weekly intake might be problematic outside a research programme.

Efficacy of zinc in young infants with acute watery diarrhea.

BACKGROUND: Recent studies reported that zinc significantly reduced the duration and volume of acute watery diarrhea in children aged > or = 4 mo, but there were no data specifically on infants aged < 6 mo. OBJECTIVE: This study investigated the effect of zinc on the duration of illness and the stool quantity in acute watery diarrhea of infants aged 1-6 mo by comparing a 20 mg Zn/d dose with a 5 mg Zn/d dose. DESIGN: Infants hospitalized with at least some dehydration (by World Health Organization classification) were enrolled in a double-blind, randomized, placebo-controlled trial. Infants were randomly assigned to receive 20 mg Zn (acetate)/d, 5 mg Zn/d, or placebo for the duration of illness. RESULTS: Two hundred seventy-five infants were enrolled between 20 September 1998 and 18 December 2000. Neither diarrhea duration nor mean stool volume differed between groups. There were no significant differences in fluid intake, the need for unscheduled intravenous fluid, weight gain, or vomiting rates between the groups. CONCLUSIONS: Zinc supplementation did not affect diarrhea duration or stool volume in young infants. Young infants tolerated both zinc doses. A beneficial effect on subsequent illness cannot be ruled out.