Restricting the use of antibiotics is unlikely to stop the spread of drug resistance in typhoid fever, according to a study funded by the Wellcome Trust and published in the journal eLife.
The findings reveal that antibiotic-resistant strains of Salmonella Typhi bacteria can out-compete drug sensitive strains when grown in the laboratory, even in the absence of antibiotics.
Typhoid fever is transmitted by consuming food or drink that is contaminated with Salmonella Typhi bacteria and the disease is linked to poor sanitation and limited access to clean drinking water. The disease can be treated but there is widespread drug resistance to common antibiotics and resistance to the recommended, more specialised antibiotic therapy for typhoid fever is increasing.
Researchers at the Oxford University Clinical Research Unit, Wellcome Trust Vietnam Research Programme, created twelve laboratory strains of Salmonella Typhi bacteria with one or more genetic mutations that confer resistance to the recommended antibiotic therapy for typhoid fever, fluoroquinolone. Typically, when bacteria develop antibiotic resistance it comes at a cost and when the drug is absent, they are usually weaker and less able to compete for food and resources than strains that are not resistant.
Dr Maciej Boni, a Sir Henry Dale Fellow funded jointly by the Wellcome Trust and Royal Society at the Oxford University Clinical Research Unit in Vietnam, who co-led the study, said: "When we grew different strains of Salmonella Typhi in the lab, we found that half of the antibiotic resistant strains had a growth advantage over their parent strain, even in the absence of antibiotic, enabling them to predominate in the population."
Dr Stephen Baker, also a Sir Henry Dale Fellow in the Oxford University Clinical Research Unit, said: "Currently, the control of typhoid across Asia and Africa relies on treatment with fluoroquinolones
|Contact: Jen Middleton|