A “superbug” strain of typhoid bacterium is driving a hidden epidemic in Africa, an international study published in Nature Genetics reveals.
Typhoid remains a major health threat in developing countries—affecting 22 million globally, according to the CDC. In Blantyre, Malawi, for example, cases jumped to 782 last year—up from an average of just 14 per year between 1998 and 2010. Multiple drug-resistance infections jumped from 7% to 97% over the same period.
By sequencing the genomes of more than 1,800 S. Typhi samples from 63 countries, a team led by Vanessa Wong, an infectious-disease specialist at the Wellcome Trust Sanger Institute in Hinxton, UK, learned that the S. Typhi strain known as H58 comprised 47% of the researchers’ samples, and showed widespread resistance to a number of antibiotics. Furthermore, drug-resistant H58 is most common in areas that rely heavily on older antibiotics, indicating that overuse of these drugs has fueled Africa’s epidemic, according to Wong and colleagues.