Rapid Emergence of Multidrug Resistant,H58-Lineage Salmonella Typhi in Blantyre,Malawi

Introduction: between 1998 and 2010,s. typhi was an uncommon cause of bloodstream infection (bsi) in blantyre,malawi and it was usually susceptible to first-line antimicrobial therapy. in 2011 an increase in a multidrug resistant (mdr) strain was detected through routine bacteriological surveillance conducted at queen elizabeth central hospital (qech). methods: longitudinal trends in culture-confirmed typhoid admissions at qech were described between 1998–2014. a retrospective review of patient cases notes was conducted,focusing on clinical presentation,prevalence of hiv and case-fatality. isolates of s. typhi were sequenced and the phylogeny of typhoid in blantyre was reconstructed and placed in a global context. results: between 1998–2010,there were a mean of 14 microbiological diagnoses of typhoid/year at qech,of which 6.8% were mdr. this increased to 67 in 2011 and 782 in 2014 at which time 97% were mdr. the disease predominantly affected children and young adults (median age 11 [iqr 6-21] in 2014). the prevalence of hiv in adult patients was 16.7% [8/48],similar to that of the general population (17.8%). overall,the case fatality rate was 2.5% (3/94). complications included anaemia,myocarditis,pneumonia and intestinal perforation. 112 isolates were sequenced and the phylogeny demonstrated the introduction and clonal expansion of the h58 lineage of s. typhi. conclusions: since 2011,there has been a rapid increase in the incidence of multidrug resistant,h58-lineage typhoid in blantyre. this is one of a number of reports of the re-emergence of typhoid in southern and eastern africa. there is an urgent need to understand the reservoirs and transmission of disease and how to arrest this regional increase. © 2015 feasey et al.