Enteric fever in Cambodian children is dominated by multidrug-resistant H58 Salmonella enterica serovar Typhi with intermediate susceptibility to ciprofloxacin

Infections with Salmonella enterica serovar Typhi isolates that are multidrug resistant (MDR: resistant to chloramphenicol, ampicillin, trimethoprim-sulphamethoxazole) with intermediate ciprofloxacin susceptibility are widespread in Asia but there is little information from Cambodia. We studied invasive salmonellosis in children at a paediatric hospital in Siem Reap, Cambodia. Between 2007 and 2011 Salmonella was isolated from a blood culture in 162 children. There were 151 children with enteric fever, including 148 serovar Typhi and three serovar Paratyphi A infections, and 11 children with a non-typhoidal Salmonella infection. Of the 148 serovar Typhi isolates 126 (85%) were MDR and 133 (90%) had intermediate ciprofloxacin susceptibility. Inpatient antimicrobial treatment was ceftriaxone alone or initial ceftriaxone followed by a step-down to oral ciprofloxacin or azithromycin. Complications developed in 37/128 (29%) children admitted with enteric fever and two (1.6%) died. There was one confirmed relapse. In a sample of 102 serovar Typhi strains genotyped by investigation of a subset of single nucleotide polymorphisms, 98 (96%) were the H58 haplotype, the majority of which had the common serine to phenylalanine substitution at codon 83 in the DNA gyrase. We conclude that antimicrobial-resistant enteric fever is common in Cambodian children and therapeutic options are limited.