A new study conducted by François-Xavier Weill, MD, and Simon Le Hello, PharmD, at the Pasteur Institute in France, has revealed a new emergence of a multidrug-resistant strain of Salmonella with a high level resistance to ciprofloxacin, a common treatment for severe Salmonella infections. The study is published in The Journal of Infectious Diseases.

With an estimated 1.7 million infections in North America each year and more than 1.6 million cases reported in 27 European countries between 1999 and 2008, Salmonella infection is a major public health problem worldwide. Most cases of Salmonella infections only produce mild gastroenteritis; however the elderly and patients with a compromised immune system are at risk for life-threatening infections. These cases are generally treated with antimicrobials called fluoroquinolones, such as ciprofloxacin.

Dr. Weill and colleagues researched studies from national surveillance systems in France, England and Wales, Denmark, and the United States. The study revealed, that 489 patients in France, England, Wales and Denmark were infected with a multidrug-resistant strain of Salmonella, known as S. Kentucky, between 2000 and 2008.

Research reported, that the first infections appeared mainly in Egypt between 2002 and 2005, whilst the infections were also acquired in various parts of Africa and the Middle East since 2006. Due to the fact that in approximately 10 percent of patients international travel can be excluded, the suggestion is that the infections may have also occurred in Europe through consumption of contaminated imported foods or through secondary contaminations.

The study isolated the multidrug-resistant S. Kentucky strain from chickens and turkeys from Ethiopia, Morocco and Nigeria, which suggests that the poultry is an important agent for infection. It is indicated that because fluoroquinolones are frequently being used in chicken and turkey production in Nigeria and Morocco, this may have contributed to the rapid dispersion.

This study draws attention to the importance of public health surveillance in a global food system. Dr. Le Hello said:

“We hope that this publication might stir awareness among national and international health, food, and agricultural authorities so that they take the necessary measures to control and stop the dissemination of this strain before it spreads globally, as did another multidrug-resistant strain of Salmonella, Typhimurium DT104, starting in the 1990s.”

A close monitoring of this multidrug-resistant strain will be continued by the Pasteur Institute and its international network, the Centers for Disease Control and Prevention in the U.S., the Health Protection Agency in the United Kingdom, and the Statens Serum Institute and Technical University of Denmark, who also help to strengthen the capacities of national and regional laboratories in the surveillance of Salmonella and other major foodborne pathogens through the World Health Organization Global Foodborne Infections Network.

In an accompanying Editorial, Craig Hedberg, PhD, from the University of Minnesota School of Public Health, stated that the ability to integrate public health surveillance by differences in national surveillance systems is limited. Dr. Le Hello’s study reports that the percentage of Salmonella isolates that have been submitted to national health reference laboratories ranged from 65 percent in France to 99 percent in Denmark. Dr Hedberg stated:

“Given the medical costs and public health impact associated with the spread of multidrug-resistant organisms, the potential benefits of such a system should far outweigh its costs.”

Fast facts:

  • 489 patients in France, England, Wales and Denmark were infected by a multidrug-resistant strain of Salmonella, known as S. Kentucky, between 2000 and 2008.
  • Poultry appear to be a major carrier for distributing these infections.
  • To limit the spread of such multidrug-resistant organisms, international public health surveillance systems are required

Written by Petra Rattue