Pakistan Health Authorities have reported an ongoing outbreak of extensively drug resistant (XDR) typhoid fever that began in the Hyderabad district of Sindh province in November 2016. An increasing trend of typhoid fever cases caused by antimicrobial resistant (AMR) strains of Salmonella enterica serovar Typhi (or S. Typhi) poses a notable public health concern. In May 2018, the case definitions for non-resistant, multi-drug resistant (MDR) and XDR typhoid fever were formally agreed by the Regional Disease Surveillance and Response Unit (RDSRU) in Karachi, following a review by an expert group of epidemiologists, clinicians and microbiologists from Pakistan. All typhoid fever cases reported from 2016 to 2018 were reviewed and classified according to these case definitions (see Table 1).
From 1 November 2016 through 9 December 2018, 5 274 cases of XDR typhoid out of 8 188 typhoid fever cases were reported by the Provincial Disease Surveillance and Response Unit (PDSRU) in Sindh province, Pakistan. Sixty-nine percent of cases were reported in Karachi (the capital city), 27% in Hyderabad district, and 4% in other districts in the province (Table 2). The circulating XDR strain of S. Typhi haplotype 58 was resistant to first and second-line antibiotics as well as third generation cephalosporins. Informal reports of XDR typhoid cases occurring in other parts of Pakistan were made and required further verification.
