Changing emergence of Shigella sero-groups in Bangladesh: observation from four different diarrheal disease hospitals

PLoS One. 2013 Apr 29;8(4):e62029. doi: 10.1371/journal.pone.0062029. Print 2013.

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.

Conclusion and significance: 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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antigens, Bacterial / blood*
  • Antigens, Bacterial / classification
  • Bangladesh / epidemiology
  • Child, Preschool
  • Diarrhea / epidemiology*
  • Diarrhea / microbiology
  • Dysentery, Bacillary / epidemiology*
  • Dysentery, Bacillary / microbiology
  • Epidemiological Monitoring
  • Feces / microbiology
  • Female
  • Hospitals, Rural*
  • Hospitals, Urban*
  • Humans
  • Infant
  • Male
  • Shigella / classification
  • Shigella / isolation & purification*

Substances

  • Antigens, Bacterial

Grants and funding

The research protocol was funded by Swedish International Development Cooperation Agency (Sida), grant number MD-0020 and GR-00599. icddr,b acknowledges with gratitude the commitment of Sida to its research efforts. Hospital surveillance was funded by icddr,b and the Government of the People’s Republic of Bangladesh through IHP-HNPRP. icddr,b acknowledges with gratitude the commitment of the Government of the People’s Republic of Bangladesh to the Centre’s research efforts. icddr,b also gratefully acknowledges the following donors who provide unrestricted support to the Centre’s research efforts: Australian Agency for International Development (AusAID), Government of the People’s Republic of Bangladesh, Canadian International Development Agency (CIDA), Embassy of the Kingdom of the Netherlands (EKN), Swedish International Development Cooperation Agency (Sida), Swiss Agency for Development and Cooperation (SDC), and Department for International Development, UK (DFID). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.