A strain of antibiotic-resistant typhoid fever continues to spread globally. The H58 “superbug” is driven by a single family of the bacteria.
A large international study that involved 74 scientists in nearly 24 countries, remains one of the most comprehensive sets of genetic data on a human infectious agent.
Their research creates a worrying scene of an “ever-increasing public health threat.”
While vaccines are available, they are limited due to cost and are not widely used in poorer countries. In regular strains of the virus, the infection is generally treated with antibiotic drugs. The study, however, found that the new H58 “superbug”, is resistant to multiple types of antibiotics and is now becoming dominant.
Typhoid, which is contracted by eating or drinking contaminated matter, is fatal in 20 percent of patients if left untreated. Symptoms include abdominal pain, nausea, fever and pink spots on the chest. If not p[roperlytreated, it can cause complications in the head and stomach.
“H58 is displacing other typhoid strains, completely transforming the genetic architecture of the disease and creating a previously underappreciated and on-going epidemic,” the researchers said in a statement about their findings.
Vanessa Wong of Britain’s Wellcome Trust Sanger Institute says that typhoid affects around 30 million people per year. The team, who collected 1,832 samples of Salmonella Typhi bacteria from 63 countries, found 47 percent were from the H58 strain.
The research team discovered the H58 strain began in South Asia about 25 years ago and has since spread to Western Asia, East and South Africa as well as Fiji, which may represent an ongoing epidemic.
Kathryn Holt, a scientist at the University of Melbourne in Australia who worked on the study, said multidrug resistant typhoid is caused by the bacteria picking up new resistance genes as disease strains mix and pass from person to person.
Resistance “has been coming and going since the 1970s”, she said, but in the H58 strain, the resistance genes are becoming a stable part of the genome “which means multiple antibiotic resistant typhoid is here to stay.”