Small distances can keep bacteria at bay for days
van Bunnik, Bram A D; Ssematimba, Amos; Hagenaars, Thomas J; Nodelijk, Gonnie; Haverkate, Manon R; Bonten, Marc J M; Hayden, Mary K; Weinstein, Robert A; De Jong, Mart C M; Bootsma, Martin C J
(2014) Proceedings of the National Academy of Sciences of the United States of America, volume 111, issue 9, pp. 3556 - 3560
(Article)
Abstract
Transmission of pathogens between spatially separated hosts, i.e., indirect transmission, is a commonly encountered phenomenon important for epidemic pathogen spread. The routes of indirect transmission often remain untraced, making it difficult to develop control strategies. Here we used a tailor-made design to study indirect transmission experimentally, using two different zoonotic
... read more
bacteria in broilers. Previous experiments using a single bacterial species yielded a delay in the onset of transmission, which we hypothesized to result from the interplay between diffusive motion of infectious material and decay of infectivity in the environment. Indeed, a mathematical model of diffusive pathogen transfer predicts a delay in transmission that depends both on the distance between hosts and on the magnitude of the pathogen decay rate. Our experiments, carried out with two bacterial species with very different decay rates in the environment, confirm the difference in transmission delay predicted by the model. These results imply that for control of an infectious agent, the time between the distant exposure and the infection event is important. To illustrate how this can work we analyzed data observed on the spread of vancomycin-resistant Enterococcus in an intensive care unit. Indeed, a delayed vancomycin-resistant Enterococcus transmission component was identified in these data, and this component disappeared in a study period in which the environment was thoroughly cleaned. Therefore, we suggest that the impact of control strategies against indirect transmission can be assessed using our model by estimating the control measures' effects on the diffusion coefficient and the pathogen decay rate.
show less
Download/Full Text
Keywords: Animals, Campylobacter Infections, Chickens, Cross Infection, Diffusion, Enterococcus, Escherichia coli Infections, Gram-Positive Bacterial Infections, Humans, Intensive Care Units, Longevity, Models, Biological, Species Specificity, Time Factors, Vancomycin Resistance, Campylobacter jejuni, Diffusion model, Escherichia coli, Transmission experiment
ISSN: 0027-8424
Publisher: National Academy of Sciences
(Peer reviewed)
See more statistics about this item