title: Changing emergence of Shigella sero-groups in Bangladesh: observation from four different diarrheal disease hospitals.
abstract: BACKGROUND
  Shigellosis continues to be a public health challenge for developing countries, including Bangladesh. The aim of the study is to demonstrate recent changes in Shigella sero-groups and their geographical diversity.
  
  
  METHODS
  Data were extracted from data archive of four diarrheal disease surveillance systems. A 2% sub sample from urban Dhaka Hospital (2008-2011; n = 10,650), and 10% from urban Mirpur Treatment Centre (2009-2011; n = 3,585), were enrolled systematically; whereas, all patients coming from the Health and Demographic Surveillance System area in rural Matlab (2008-2011; n = 6,399) and rural Mirzapur (2010-2011; n = 2,812) were included irrespective of age, sex, and disease severity. A fresh stool specimen was collected for identification of Shigella spp. Of them, 315 (3%) were positive for Shigella in Dhaka, 490 (8%) from Matlab, 109 (3%) from Mirpur and 369 (13%) from Mirzapur and considered as analyzable sample size.
  
  
  RESULTS
  Among all Shigella isolates regardless of age, significant decreases in percentage of S. flexneri over time was observed in Mirpur (55→29%; p value of χ(2)-for trend = 0.019) and Mirzapur (59→47%; p = 0.025). A non-significant decrease was also seen in Dhaka (58→48%), while in Matlab there was a non-significant increase (73→81%). Similar patterns were observed among under-5 children at all sites. Emergence of S. sonnei was found in Dhaka (8→25%; p<0.001) and Mirpur (10→33%; p = 0.015), whereas it decreased in Mirzapur (32→23%; p = 0.056). The emergence of S. boydii was seen in all ages in Mirzapur [(3→28%; p<0.001); (3→27%; p<0.001)]. On the other hand, we saw non-significant percent reductions in S. boydii in Dhaka [overall (25→16%); under-5 (16→9%)]. Decreasing rates of Shigella dysenteriae were observed in Matlab, Mirpur and Mirzapur; whereas, in Dhaka it remained unchanged.
  
  
  CONCLUSIONS
  Emergence of S. sonnei and S. boydii as important infectious diarrhea etiologies and variations in geographical diversity underscore the need for monitoring, with possible implications for vaccine development.
authors: Centre for Nutrition and Food Security (CNFS), International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b), Dhaka, Bangladesh.
authors: Sumon Kumar
authors: SK
authors: Das
authors: Shahnawaz
authors: S
authors: Ahmed
authors: Farzana
authors: F
authors: Ferdous
authors: Fahmida Dil
authors: FD
authors: Farzana
authors: Mohammod Jobayer
authors: MJ
authors: Chisti
authors: Daniel T
authors: DT
authors: Leung
authors: Mohammad Abdul
authors: MA
authors: Malek
authors: Kaisar Ali
authors: KA
authors: Talukder
authors: Pradip Kumar
authors: PK
authors: Bardhan
authors: Mohammed Abdus
authors: MA
authors: Salam
authors: Abu Syed Golam
authors: AS
authors: Faruque
authors: Rubhana
authors: R
authors: Raqib
mesh_terms: D000942:Antigens, Bacterial / Q000097:blood* / Q000145:classification; D001459:Bangladesh / Q000453:epidemiology; D002675:Child, Preschool; D003967:Diarrhea / Q000453:epidemiology* / Q000382:microbiology; D004405:Dysentery, Bacillary / Q000453:epidemiology* / Q000382:microbiology; D062665:Epidemiological Monitoring; D005243:Feces / Q000382:microbiology; D005260:Female; D006780:Hospitals, Rural; D006786:Hospitals, Urban; D006801:Humans; D007223:Infant; D008297:Male; D012760:Shigella / Q000145:classification / Q000302:isolation & purification*
chemical_list: D000942:Antigens, Bacterial
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