| Abstract: | We identified 3 lineages among multidrug-resistant (MDR) Salmonella
enterica serotype Typhi isolates in the Gulf of Guinea region in
Africa during the 2000s. However, the MDR H58 haplotype, which predominates in
southern Asia and Kenya, was not identified. MDR quinolone-susceptible isolates
contained a 190-kb incHI1 pST2 plasmid or a 50-kb incN pST3 plasmid.Typhoid fever, which is caused by Salmonella enterica serotype Typhi, is
endemic to the developing world; there were an estimated 26.7 million cases in 2010
(1). The incidence of typhoid
fever in sub-Saharan Africa was an estimated 725 cases/100,000 persons in 2010, despite
a lack of incidence studies conducted in West and central Africa (1). Antimicrobial susceptibility data are also
scarce for this part of Africa. This issue is problematic because treatment with
appropriate antimicrobial drugs is essential for recovery in the context of the global
emergence of multidrug resistance.In the Indian subcontinent and Southeast Asia, the multidrug-resistant (MDR)
Salmonella Typhi H58 clone, which was named after its haplotype (a
combination of defined chromosomal single-nucleotide polymorphisms SNPs]) (2,3), has spread rapidly and become
endemic and predominant. During the 1990s, this clone acquired a large conjugative
incHI1 pST6 plasmid encoding resistance to ampicillin, chloramphenicol, and
co-trimoxazole (4,5); also in the 1990s, this MDR clone became resistant
to quinolones and showed decreased susceptibility to ciprofloxacin because of point
mutations in the chromosomal gyrA gene (2). The H58 clone has also spread to eastern Africa,
where it has been the most prevalent haplotype (87%) in Kenya since the early 2000s
(6).During 1997–2011, high incidence of MDR Salmonella Typhi was
reported in some countries near the Gulf of Guinea in Africa, including Nigeria (7), Ghana (8,9), Togo (10), and the Democratic Republic of the Congo (11). During 1999–2003, a
British surveillance system reported a prevalence of 19% (49/421) for MDR
Salmonella Typhi isolates among imported cases of typhoid fever
acquired in Africa, particularly in Ghana (12). However, nothing is known about the genotypes of
these isolates, including whether they belong to the spreading MDR H58 clone.We report data for the occurrence, genotypes, and characterization of the resistance
mechanisms of MDR Salmonella Typhi isolates. These isolates were
obtained from the French National Reference Center for Salmonella
(FNRC-Salm), Institut Pasteur (Paris, France), and Centre Pasteur du Cameroun
(Yaoundé, Cameroon). |
