Did you know that a potentially dangerous strain of Salmonella has been quietly spreading for longer than we thought? Here’s the shocking truth: Salmonella enterica ST8333 was first isolated as early as July 2015, not 2017 as previously believed. But here’s where it gets controversial—this discovery raises questions about how well we’re tracking the origins and spread of such pathogens. Let’s dive into the details and uncover what most people might have missed.
In a recent study, Cui et al. reported the identification of 31 Salmonella enterica serovar I 1,4,[5],12:i:- (S. I 1,4,[5],12:i:-) sequence type 8333 (ST8333) genomes in China’s National Molecular Tracing Network for Foodborne Disease Surveillance database by the end of 2023. While their findings highlighted the strain’s presence between 2017 and 2023, our deeper investigation reveals a more alarming timeline. ST8333 was first assigned in the EnteroBase database on January 15, 2021, based on seven housekeeping genes. However, the earliest isolation of this strain dates back to July 25, 2015, from a 1-year-old boy in Xinjiang, China. This means the strain had been circulating for at least two years before it was officially recognized.
And this is the part most people miss—our analysis suggests that endemic transmission likely occurred in Xinjiang as early as 2015, with the strain later spreading to other regions like Sichuan and Shaanxi. This challenges the notion that Qinghai Province was the origin point in 2017, as proposed by Cui et al. The limited genomic data available at the time may have skewed their conclusions, underscoring the need for more comprehensive data sharing in the scientific community.
But why does this matter? Salmonella enterica ST8333 is not just any strain—it’s evolving from S. I 1,4,[5],12:i:- ST34, a lineage notorious for multidrug resistance (MDR). Our in silico analysis revealed 124 acquired antibiotic resistance genes (ARGs), with some strains carrying resistance to third-generation cephalosporins and fluoroquinolones. Worse, the number of ARGs and mobile genetic elements (MGEs) has increased over time, indicating a growing threat to public health.
Here’s the burning question: Could ST8333 replace ST34 as the dominant sequence type causing human infections globally? While it’s too early to say for sure, the rising number of infections and the strain’s ability to acquire resistance genes are cause for concern. This isn’t just a local issue—Salmonella enterica is on the World Health Organization’s 2024 Bacterial Priority Pathogens List, and antimicrobial resistance (AMR) is one of the top 10 public health threats worldwide.
To combat this, we urgently need more publicly available genomic data on S. I 1,4,[5],12:i:- and S. Typhimurium. Advances in whole-genome sequencing (WGS) and artificial intelligence (AI) have made it possible to track the spatiotemporal evolution of AMR, but only if we have the data to work with. Failure to address this gap could lead to underestimating the risk of MDR ST8333 transmission and the emergence of new variants.
Considering the strain’s presence in meat products like pork, we must prioritize sequencing and sharing data from animal and food sources. The correlation between meat production, population density, temperature, and AMR in Salmonella cannot be ignored. So, here’s our call to action: Let’s unite the scientific community to build robust, open-access genomic databases that can inform outbreak responses and shape prevention policies in real time.
What do you think? Is enough being done to track and combat the spread of strains like ST8333? Share your thoughts in the comments—let’s spark a conversation that could drive change.
