<i>mtlA,</i> a novel typing gene offering enhanced resolution for pandemic <i>Vibrio</i> species

The gene <i>mtlA</i>, encoding the mannitol transporter subunit IICBA of the phosphotransferase system, was the core gene with the greatest variability in <i>Vibrio parahaemolyticus</i> and could be used as a new typing marker in <i>Vibrio parahaemolyticus</i>. To expand its application, we performed an evolutionary analysis and found that the <i>mtlA</i> gene was present in nine phyla, 371 genera, and 1,662 species of bacteria. It is commonly found in pathogenic species of <i>Vibrio</i>, followed by <i>Paenibacillus</i>, <i>Mycolicibacterium</i>, etc. To investigate whether the <i>mtlA</i> gene could serve as a novel typing gene for whole <i>Vibrio</i> species, we compared the typing effect of the <i>mtlA</i> gene with multilocus sequence type (MLST) in 13 common pathogenic <i>Vibrio</i> species. The results revealed that the <i>mtlA</i> gene was present in all common pathogenic species, providing comparable or even higher typing resolution than MLST, especially in <i>Vibrio cholerae</i>, <i>Vibrio alginolyticus</i>, <i>Vibrio harveyi</i>, and <i>Vibrio anguillarum</i>, enabling accurate typing and traceability; however, many species lacked allelic profiles of MLST genes, making it impossible to obtain accurate STs. In summary, these findings validated the potential typing application of the <i>mtlA</i> gene in <i>Vibrio</i> species.IMPORTANCE<i>Vibrio</i> is a collection of gram-negative bacteria characterized by possessing two chromosomes, which exhibit numerous shared biological and genomic traits. Around 13 species of <i>Vibrio</i> are known to cause infections in humans. Without appropriate medical interventions, the consequences of these infections can escalate to become life-threatening. Therefore, based on the prevalent characteristics of pathogenic <i>Vibrio</i>, it is imperative for us to classify and trace various <i>Vibrio</i> species that cause human illness and prescribe medication rationally to control the spread of diseases. In our investigation, we explored the prevalence and typing accuracy of the <i>mtlA</i> gene in <i>Vibrio</i>. Our findings revealed its ubiquitous presence across typical pathogenic <i>Vibrio</i> species, offering superior typing efficacy compared with MLST and more extensive implications.