Research Highlights

Drug-resistant salmonella on the rise in region

Published online 4 July 2013

Biplab Das

A drug-resistant strain of Salmonella enterica found in Middle Eastern and African countries is becoming a predominant strain and is spreading throughout region, according to a study published in the Lancet Infectious Diseases1.

The study highlights the spread of a strain, known as S Kentucky ST198-X1 and identified genetic mutations that led to it acquiring resistance to antibiotics. This strain was mostly identified in Egypt before 2005, but has since spread rapidly throughout Africa and the Middle East.

The researchers analyzed hundreds of subcultures of strain ST198-X1 from France and Morocco and found a significant increase in the proportion of isolates resistant to ciprofloxcin, the antibiotic of choice against salmonella. They found that 83% of the isolates from 2009–2011 were found to be drug-resistant, compared to only 40% sampled between 2000 and 2008.

Gene sequencing of the strains isolated from patients from Egypt and West Africa also revealed that these strains underwent genetic mutations, making them resistant to ciprofloxacin. They also identified genes that made the strain resistant to other antibiotics such as carbapenem and azithromycin.

"Currently, we are performing a whole genome sequencing to find any genetic determinants not associated with antimicrobial resistance which might yield clues to better disinfection or environmental control measures in poultry farms," says François-Xavier Weill, a senior author of the study.


  1. Hello, S. L. et al. Highly drug-resistant Salmonella enterica serotype Kentucky ST198-X1: a microbiological study. Lancet. Infect. Dis. (2013) doi:10.1016/S0140-6736(08)61345-8