Molecular Epidemiology and Drug Resistance of Extraintestinal Pathogenic Escherichia coli Bloodstream Isolates From Adults Worldwide (2011–2023)

Background
Extraintestinal pathogenic Escherichia coli (ExPEC) can colonize and infect body sites outside the intestines, which can lead to invasive E. coli disease potentially resulting in sepsis or death. We evaluated O-serotype distribution, antimicrobial resistance profiles, and sequence types (STs) of ExPEC bloodstream isolates collected during 17 global surveillance studies conducted from 2011 through 2023.

Methods
E. coli clinical blood isolates from an adult population were analyzed for O-serotype, ST, and multidrug-resistance (MDR) using data obtained by agglutination, whole-genome sequencing, and determination of minimal inhibitory concentrations of antimicrobial drugs.

Results
Globally, 10 098 E. coli isolates were collected; 4925 (48.8%) from men and 5136 (50.9%) from women, median (range) age was 72 (18–104) years. The most prevalent ExPEC O-serotypes were O25 (18.7%), O2 (8.2%), O6 (8.2%), and O1 (7.0%). Highest MDR rates were observed in India (83.3%), Mexico (76.6%), and China (69.4%); lowest rates were in Sweden (10.6%), New Zealand (11.6%), and Netherlands (12.1%). Among MDR isolates (n=3343), serotype O25 was the most prevalent in all countries (range: 11.3% China to 56.2% Mexico). We observed a resistance rate of 1.1% and 0.7% to last-resort carbapenem and colistin antibiotics, respectively, distributed over diverse STs and O-serotypes.

Conclusions
Overall, serotypes O25, O2, O6, and O1 were the most prevalent. MDR levels showed large regional variation. O25 was dominant within the subset of MDR isolates across all countries. O153-ST648, O101/O162-ST744, O102-ST405, and O25-ST131 were associated with MDR.