Global phylogeography and antibiotic resistance characteristics of Morganella: An epidemiological, spatial, comparative genomic study.

Morganella morganii has been recognized as an important opportunistic pathogen that is becoming increasingly prevalent worldwide. However, the current global evolutionary dynamics and emergence of ARGs remain obscure. The present study determined the global distribution, genomic classification, phylogeny, and monitor longitudinal resistome changes. During 1900-2024, a total of 1027 non-duplicate Morganella genomes have been reported from 49 countries. The countries with the highest number were China (433), the USA (143), and France (74). Through ANI distance analysis and core genome phylogeny, Morganella was reclassified into six species: M. morganii, M. sibonii, M. chanii, M. laugraudii, M. kristinii, M. psychrotolerans. Further analysis using cgMLST identified 87 distinct genetic clusters and 737 singleton strains, indicating a high level of multi-locus sequence type diversity and local clonal outbreaks. Bayesian evolutionary analysis revealed the most recent common ancestor year and potential global transmission routes. A total of 195 ARGs were carried by Morganella isolates, with each genome containing between 2 and 544 ARGs. The most common ARGs were associated with resistance to the following drug-classes: aminoglycosides, beta-lactam, chloramphenicol, sulfamides, and tetracycline. Twenty-one carbapenemase-encoding genes were identified in 22 countries, with bla, bla, bla, bla, bla, bla, and bla being the most prevalent. Positive correlations were observed between ARGs and mobile genetic elements, like plasmids, ISs, and Tns, indicating frequent mobilization of certain ARGs by different mobile genetic elements (p < 0.05). In conclusion, Morganella isolates that are showing an upward trend in resistance and infection rates warrant a reclassification of their taxonomy and continuous monitoring for resistance.