Basic reproduction number varies markedly between closely related pandemic Escherichia coli clones

Extra-intestinal pathogenic Escherichia coli ubiquitously colonize the human gut and represent clinically the most significant bacterial species causing urinary tract infections and bacteremia. During the last two decades clades of the ST131 lineage have spread globally, but it remains unknown how their transmission dynamics compare to the basic reproduction numbers (R₀) for viral pandemics. We develop a compartmental model for asymptomatic gut colonization and onward transmission coupled with an epidemiological observation model and fit it on the major ST131 clades. Our results indicate that the ST131-A transmission potential (R₀ = 1.47) can be comparable to pandemic influenza viruses, while the significantly lower transmissibility of ST131-C1 (R₀ = 1.18) and ST131-C2 (R₀ = 1.13) suggests that their dissemination has been aided by antibiotic selection pressure and healthcare facilities. Our results provide an advance in understanding the relative transmissibility of these opportunistic pathogens.