Salmonella carriage in adopted children from Mali: 2001-08

Salmonella spp. are among the most frequently encountered bacterial pathogens in children adopted abroad, especially from developing countries. The aim of this study was to investigate the carriage of Salmonella in international adoptees over an 84 month period. This screening programme was initiated after serious infections occurred in adopted children.

Stool samples taken at the first visit to the outpatient adoption practice and subsequently every month from children adopted from an orphanage in Bamako (Mali) and from all members of their adoptive families were screened for Salmonella. Bacteria were characterized by standard biochemical methods, serotyping, disc diffusion antibiograms and PFGE. β-Lactamase genes were sought by PCR.

Over the study period, 55 families that adopted 61 children from the state orphanage of Bamako were surveyed. Ninety-two Salmonella spp. were isolated from faecal samples from 30 families that had adopted a child. The isolates were all identified as Salmonella enterica of different serovars, Babelsberg and Enteritidis being the most prevalent. PFGE classified the Salmonella isolates into nine genotypic profiles matching with their serovar. Of the 41 non-duplicate isolates, 8 were susceptible to all tested antibiotics and 26 Salmonella isolates produced an extended-spectrum β-lactamase (ESBL). PCR and DNA sequencing revealed that all the ESBL-producing isolates harboured the bla(TEM-1) gene, 21 isolates harboured in addition the bla(SHV-12) gene and the 5 remaining isolates harboured the bla(CTX-M-15) gene.

International adoption may contribute to the global emergence and spread of multidrug-resistant Salmonella.