Helicobacter pylori infection in Bamako (Mali): Polymorphism, diversity and prophage

Abstract

Helicobacter pylori (Hp) is a bacteria associated with gastritis and gastric cancer (GC). Its prevalence is higher than 80% in Mali and affects the incidence of GC, which is a major cancer in the department of digestive surgery. VacA and CagA toxins are responsible of Hp strain polymorphism. With prophage, they are also associated with a region depending diversity. The aim of this study was to identify the variants of Hp strains and their prophage identity in Bamako (Mali). A total of 61 gastric biopsies were isolated in patients with gastric diseases. The extracted DNA was amplified by PCR targeting cagA, vacA (s, m) and phage integrase (int) genes. cagA and int amplicons were sequenced according to Sanger method. Hp was detected in 23 (37.7%) samples. A predominance of housewives, commercial workers, farmers and students was observed, confirming the importance of socio-economic conditions and the associated factors in Hp infection. Carcinogenic vacAs1m1 was the second dominant polymorph. This would explain the prevalence of Hp's GC in the country. The phylogenetic tree from cagA sequences has revealed the specific variants strain of Hp that causes gastritis in Mali (HpML). Their prophage integration protein shares more than 90% of its sequence with species of the Schmidvirus genus. Like the HpML probable strains, Malian’s Hp prophage (HpMLpΦ) is geographically clustered with hspWestAfrica1 (hpAfrica1). These results confirm the existence of probable Hp and bacteriophage specific strains to Mali and suggest that using the molecular diagnostics method for effective pathogen identification and rapid patient management.