A three-year review of antimicrobial resistance of Salmonella enterica serovars Typhi and Paratyphi A in Pakistan

Introduction: Enteric fever is among the most common bacteraemic illnesses in South Asia. Multidrug resistance as well as fluoroquinolone resistance has severely limited therapeutic options in high disease burden countries such as Pakistan. This review was conducted to determine the frequency of drug-resistant Salmonella enterica serovar Typhi (S.Typhi) and Salmonella enterica serovar Paratyphi A (S. Paratyphi A) between2009 and 2011. Methodology: This study was a review of laboratory data. The antibiotic susceptibility of typhoidal Salmonellae isolated from blood cultures submitted to the Aga Khan University Hospital's laboratory from all over Pakistan between January 2009 and December 2011 were reviewed. Results: The sensitivity data of 4,323 positive isolates of S. Typhi and S. Paratyphi A isolated during the three-year period were reviewed. The majority of isolates were S. Typhi (59.6%).Over three years, the incidence of multidrug-resistant (MDR) S.Typhi remained high, ranging from 64.8%-66.0%, while MDR S. Paratyphi A decreased from 4.2% to 0.6%.Fluoroquinolone resistance increased for S. Typhi from 84.7% to 91.7%.Cefixime- and ceftriaxone-resistant S. Typhi were isolated in two children. Conclusions: Our results show high rates of multidrug and fluoroquinolone resistance among S. Typhi and S. Paratyphi. The occurrence of two cases of ceftriaxone resistance is alarming.