Modelling the epidemiology of Escherichia coli ST131 and the impact of interventions on the community and healthcare centres

Abstract

ST131 Escherichia coli is an emergent clonal group that has achieved successful worldwide spread through a combination of virulence and antimicrobial resistance. Our aim was to develop a mathematical model, based on current knowledge of the epidemiology of ESBL-producing and non-ESBL-producing ST131 E. coli, to provide a framework enabling a better understanding of its spread within the community, in hospitals and long-term care facilities, and the potential impact of specific interventions on the rates of infection. A model belonging to the SEIS (Susceptible-Exposed-Infected-Susceptible) class of compartmental models, with specific modifications, was developed. Quantification of the model is based on the law of mass preservation, which helps determine the relationships between flows of individuals and different compartments. Quantification is deterministic or probabilistic depending on subpopulation size. The assumptions for the model are based on several developed epidemiological studies. Based on the assumptions of the model, an intervention capable of sustaining a 25% reduction in person-to-person transmission shows a significant reduction in the rate of infections caused by ST131; the impact is higher for non-ESBL-producing ST131 isolates than for ESBL producers. On the other hand, an isolated intervention reducing exposure to antimicrobial agents has much more limited impact on the rate of ST131 infection. Our results suggest that interventions achieving a continuous reduction in the transmission of ST131 in households, nursing homes and hospitals offer the best chance of reducing the burden of the infections caused by these isolates.

Application of dynamic modelling techniques to the problem of antibacterial use and resistance: a scoping review

“…Twelve studies simulate treatment with antibiotics from multiple classes [35, 53, 55, 56, 67, 73, 82, 88, 90, 93, 96, 103]. Treatment with beta-lactams (including carbapenems, cephalosporins and penicillins) is most frequently simulated ( n = 17), while fluoroquinolone [53, 67, 73] and macrolide [82, 90, 93, 103] treatments are simulated less often. The single example of treatment with tetracycline concerns the spread of tetracycline-resistant Escherichia coli in pigs [34].…”

“…In contrast, individual or ABM represent the system as a population of heterogeneous entities engaged in local interactions; models of this type better capture the stochastic behaviour of a system but impose opportunity costs related to model construction, parameterisation and computing time [114]. Opatowski and colleagues [30] argue that increasingly realistic predictions arising from ABM models are likely to advance the utility of computer simulations for 1 month ⩽ x <1 year [42] 1 year ⩽ x <10 years [35,37,41,42,64,67,70,71,73,88,90,97] 10 years ⩽ x <50 years [59,66,89,92,93,99,101,103] 50 years ⩽ x [ 59,66,79,93,94,102] Undefined time steps [109] Undefined steady state [46,51,53,63,110] Distribution of values reported as mean or range 1 week ⩽ x <1 month [55] 1 month ⩽ x <1 year [82] 1 year ⩽ x <10 years [49,56,69,72,83] 10 years ⩽ x <50 years [36,…”

Intestinal colonization due to Escherichia coli ST131: risk factors and prevalence

“…In hospitals, the risk factors found (dependence for basic activities and urinary catheter) might also be associated with increased need for care and contact. These results suggest that direct contact would be a prominent mechanism of transmission for ST131 and build on the concept that avoiding such direct person-to-person transmission would be critical to reduce the spread of these isolates [ 9 ].…”

Prevalence and transmission dynamics of Escherichia coli ST131 among contacts of infected community and hospitalized patients

“…Studies focused on ESBL producers (including isolates belonging to ST131) in nursing homes suggested that behaviour was more like households than hospitals [25]. A mathematical model showed that avoiding person-to-person transmission was more efficacious than reducing exposure to antibiotics [26]. a This patient was colonized with non-ST131 CTX-M-1-producing Escherichia coli belonging to D2 group.…”