Superbug typhoid silently spreading, researchers warns

Landmark study shows drug-resistant strain of typhoid becoming widespread in Asia and Africa

Photo by: Reuters
Photo by: Reuters

Updated Jul 28, 2015

Researchers have found that one single drug-resistant strain of typhoid, H58, is responsible for an under radar epidemic in Asia and Africa. A paper, written with the collaboration of 74 researchers and published in Nature Genetics on Monday, shows that superbug H58 has spread worldwide and it is originated from South Asia 2-3 decades ago. Typhoid is caused by Salmonella Typhi and contracted by ingesting contaminated matter. Nausea, fever, abdominal pain and pink spots on the chest are best known symptoms. If left untreated, the disease can claim the life of two out of 10 patients. "Typhoid affects around 30 million people each year and global surveillance at this scale is critical to address the ever-increasing public health threat caused by multidrug resistant typhoid in many developing countries around the world," says Dr Vanessa Wong, first author of the paper, in a statement from the Wellcome Trust Sanger Institute. The first superbugs resistant to multiple antibiotics surfaced in 1970s. But what concerns the researchers about H58 is that it is “displacing other typhoid strains” and “completely transforming the genetic architecture of the disease.” “Multidrug resistant typhoid has been coming and going since the 1970s and is caused by the bacteria picking up novel antimicrobial resistance genes, which are usually lost when we switch to a new drug," says Dr Kathryn Holt, senior author from Melbourne University, in the same statement. "In H58, these genes are becoming a stable part of the genome, which means multiple antibiotic resistant typhoid is here to stay." The geneticists found that the H58 strain was dominant with a 47 percent presence in the sequenced genomes of 1,832 Salmonella Typhi bacteria, collected from 63 countries between 1992 and 2013. After its emergence in South Asia 25 to 30 years ago, H58 travelled to Southeast Asia, Western Asia, East and South Africa and Fiji.

TRTWorld and agencies