Infectious Diseases 2020

Infectious Diseases 2020

Salmonella infantis a new emergent clone

Tyson et al (2020) Microbial Drug Resistance 29 November, 2020

Salmonella enterica serovar Infantis has been among the top 10 serotypes causing human illness in the United States every year since 2010. Recently, there have been reports worldwide of a multidrug-resistant, emergent Salmonella Infantis (ESI) clone with a large megaplasmid (pESI), often containing the extended-spectrum beta-lactamase gene blaCTX-M-65. This clone also has a gyrA mutation conferring fluoroquinolone resistance, further limiting treatment options. In the United States, this clone has also been found in poultry sources, indicating a likely source of human illnesses. The ESI clone was first found in retail meats in Tennessee in 2014, but by 2019 was throughout the United States and comprised 29% of all Salmonella isolated from retail chickens, and 7% from retail turkey. This clone demonstrates a rapid spread of Salmonella Infantis in poultry in the United States, with the potential for increased burden of human illness attributed to this multidrug-resistant pathogen. The emergence of the ESI clone of Salmonella Infantis is concerning, as its sudden rise in retail meats and contributions to human illnesses is combined with a propensity for multidrug-resistance.