title: The Prevalence of Mixed Helicobacter pylori Infections in Symptomatic and Asymptomatic Subjects in Dhaka, Bangladesh.
abstract: BACKGROUND
  Helicobacter pylori is a highly genetically diverse bacterial species, which can persist in the gastric environment for decades. Recent studies have shown that single infections predominate in developed countries, whereas mixed infections are more prevalent in developing countries. Mixed infections of this bacterium may be important for adaptation to the hostile gastric environment and may facilitate dyspeptic symptoms.
  
  
  METHODS
  To calculate the prevalence of mixed infections in symptomatic and asymptomatic subjects, 2010 H. pylori isolates collected from 83 symptomatic and 91 asymptomatic subjects from Dhaka, Bangladesh, were analyzed by (i) random amplified polymorphic DNA fingerprinting (RAPD) and (ii) multiplex PCR amplification for cagA and vacA virulence gene alleles.
  
  
  RESULTS
  The overall prevalence of mixed H. pylori infection was 60.15% (77/128), indicating substantial co-colonization in this population. We additionally found that symptomatic subjects (53%) had a significantly higher rate of mixed infection than asymptomatic individuals (36.3%) (p = .016) and that the prevalence of the cagA and vacA and vacA m1/s1 and vacA m2/s1 alleles were higher in subjects with mixed infection.
  
  
  CONCLUSIONS
  Our findings suggest that an increased diversity of the H. pylori strains in the gastric environment may contribute to the development of disease symptoms.
authors.affiliation: Mawlana Bhashani Science and Technology University, Shantosh, Tangail, Bangladesh.
authors.forename: Khandoker Mohammad K
authors.initials: KM
authors.lastname: Kibria
authors.affiliation: International Centre for Diarrhoeal Disease Research, Dhaka, Bangladesh.
authors.forename: Md Enayet
authors.initials: ME
authors.lastname: Hossain
authors.affiliation: North-South University, Dhaka, Bangladesh.
authors.forename: Jinath
authors.initials: J
authors.lastname: Sultana
authors.affiliation: International Centre for Diarrhoeal Disease Research, Dhaka, Bangladesh.
authors.forename: Shafiqul A
authors.initials: SA
authors.lastname: Sarker
authors.affiliation: International Centre for Diarrhoeal Disease Research, Dhaka, Bangladesh.
authors.forename: Pradip Kumar
authors.initials: PK
authors.lastname: Bardhan
authors.affiliation: Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam.
authors.forename: Motiur
authors.initials: M
authors.lastname: Rahman
authors.affiliation: International Centre for Diarrhoeal Disease Research, Dhaka, Bangladesh.
authors.forename: Shamsun
authors.initials: S
authors.lastname: Nahar
mesh_terms: D000328:Adult; D000942:Antigens, Bacterial / Q000235:genetics; D058070:Asymptomatic Diseases; D001426:Bacterial Proteins / Q000235:genetics; D001459:Bangladesh / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D060085:Coinfection / Q000453:epidemiology* / Q000382:microbiology* / Q000473:pathology; D005260:Female; D014644:Genetic Variation; D016481:Helicobacter Infections / Q000453:epidemiology* / Q000382:microbiology* / Q000473:pathology; D016480:Helicobacter pylori / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification*; D006801:Humans; D008297:Male; D017720:Molecular Epidemiology; D058889:Molecular Typing; D015995:Prevalence; D019105:Random Amplified Polymorphic DNA Technique
chemical_list: D000942:Antigens, Bacterial; D001426:Bacterial Proteins; C074689:VacA protein, Helicobacter pylori; C080866:cagA protein, Helicobacter pylori
keywords: Bangladesh; Helicobacter pylori; cagA; mixed infection; vacA