Dispersal of antibiotic-resistant high-risk clones by hospital networks: changing the patient direction can make all the difference.
BACKGROUND
Patients who seek treatment in hospitals can introduce high-risk clones of hospital-acquired, antibiotic-resistant pathogens from previous admissions. In this manner, different healthcare institutions become linked epidemiologically. All links combined form the national patient referral network, through which high-risk clones can propagate.


OBJECTIVE
To assess the influence of changes in referral patterns and network structure on the dispersal of these pathogens.


METHODS
Hospital admission data were mapped to reconstruct the English patient referral network, and 12 geographically distinct healthcare collectives were identified. The number of patients admitted and referred to hospitals outside their collective was measured. Simulation models were used to assess the influence of changing network structure on the spread of hospital-acquired pathogens.


RESULTS
Simulation models showed that decreasing the number of between-collective referrals by redirecting, on average, just 1.5 patients/hospital/day had a strong effect on dispersal. By decreasing the number of between-collective referrals, the spread of high-risk clones through the network can be reduced by 36%. Conversely, by creating supra-regional specialist centres that provide specialist care at national level, the rate of dispersal can increase by 48%.


CONCLUSIONS
The structure of the patient referral network has a profound effect on the epidemic behaviour of high-risk clones. Any changes that affect the number of referrals between healthcare collectives, inevitably affect the national dispersal of these pathogens. These effects should be taken into account when creating national specialist centres, which may jeopardize control efforts.
Department of Medical Microbiology, University Medical Centre Groningen, University of Groningen, The Netherlands; Centre for Infectious Disease Control, National Institute for Public Health and the Environment, Bilthoven, The Netherlands. Electronic address: t.donker@umcg.nl.
T
T
Donker
Centre for Infectious Disease Control, National Institute for Public Health and the Environment, Bilthoven, The Netherlands.
J
J
Wallinga
Department of Medical Microbiology, University Medical Centre Groningen, University of Groningen, The Netherlands; Centre for Infectious Disease Control, National Institute for Public Health and the Environment, Bilthoven, The Netherlands.
H
H
Grundmann
D001419:Bacteria / Q000187:drug effects* / Q000302:isolation & purification; D001424:Bacterial Infections / Q000453:epidemiology / Q000382:microbiology* / Q000635:transmission*; D003428:Cross Infection / Q000453:epidemiology / Q000382:microbiology* / Q000635:transmission*; D024881:Drug Resistance, Bacterial; D004739:England / Q000453:epidemiology; D058872:Epidemics; D006761:Hospitals; D006801:Humans; D012017:Referral and Consultation
Antibiotic resistance; Network; Referral patterns