Transmission of gram-negative antibiotic-resistant bacteria following differing exposure to antibiotic-resistance reservoirs in a rural community: a modelling study for bloodstream infections

Abstract

Exposure to community reservoirs of gram-negative antibiotic-resistant bacteria (GN-ARB) genes poses substantial health risks to individuals, complicating potential infections. Transmission networks and population dynamics remain unclear, particularly in resource-poor communities. We use a dynamic compartment model to assess GN-ARB transmission quantitatively, including the susceptible, colonised, infected, and removed populations at the community-hospital interface. We used two side streams to distinguish between individuals at high- and low-risk exposure to community ARB reservoirs. The model was calibrated using data from a cross-sectional cohort study (N = 357) in Chile and supplemented by existing literature. Most individuals acquired ARB from the community reservoirs (98%) rather than the hospital. High exposure to GN-ARB reservoirs was associated with 17% and 16% greater prevalence for GN-ARB carriage in the hospital and community settings, respectively. The higher exposure has led to 16% more infections and attributed mortality. Our results highlight the need for early-stage identification and testing capability of bloodstream infections caused by GN-ARB through a faster response at the community level, where most GN-ARB are likely to be acquired. Increasing treatment rates for individuals colonised or infected by GN-ARB and controlling the exposure to antibiotic consumption and GN-ARB reservoirs, is crucial to curve GN-ABR transmission.

Modeling the transmission of antibiotic-resistant Enterobacterales in the community: a systematic review

“…Our search returned 192 publications, of which 18 met inclusion criteria and were included in the review (see PRISMA flowchart in Figure 1). 22–39…”

“…Two studies specifically focused on high-risk groups, either returning travelers or returning hospitalized patients. 25,37 Concerning antibiotic use, ten studies explicitly used parameter values obtained from high income countries (France, Sweden, Switzerland, United Kingdom, United States, or European countries), two studies focused on low-resource villages in South America (Ecuador and Chile), 31,39 while two studies used theoretical parameters, and the remaining four did not specify antibiotic use parameters. While eleven models focused on community settings only, seven explicitly modeled both community and healthcare settings, considering setting-specific transmission parameters and antibiotic use rates.…”

“…Knight et al and Allel et al explored the relative contribution of community versus healthcare settings in the overall transmission of antibiotic resistance. 38,39 Their results both suggested that individuals from the general population mostly acquired resistant E. coli or other Gram-negative bacteria in the community, despite higher levels of antibiotic use and transmission in the hospital. 38,39 Within the community, multiple transmission routes were investigated in Mughini-Gras et al, such as human, food, environment, farm and companion animals.…”

“…38,39 Their results both suggested that individuals from the general population mostly acquired resistant E. coli or other Gram-negative bacteria in the community, despite higher levels of antibiotic use and transmission in the hospital. 38,39 Within the community, multiple transmission routes were investigated in Mughini-Gras et al, such as human, food, environment, farm and companion animals. 23 Using a source-attribution model, they estimated that 60% of community carriage of ESBL-producing Enterobacterales originated from human-to-human transmission.…”

“…Several of the reviewed studies were not species-specific but rather considered generic Enterobacterales or intestinal commensals, 29,35,36,39 with two of them using epidemiological parameters previously estimated for S. pneumoniae . 29,35 However, Enterobacterales and S. pneumoniae do not share the same ecological niche within the host (mainly gut vs upper respiratory tract) and differ in primary transmission routes (direct or indirect orofecal vs airborne transmission), antibiotic resistance mechanisms (e.g., efflux pumps removing antibiotics from the cell in some strains of macrolide-resistant S. pneumoniae versus the production of antibiotic-degrading enzymes among ESBL-producing Enterobacterales) or in the fraction of the human population that are carriers.…”