Why sensitive bacteria are resistant to hospital infection control

Wellcome Open Research

article

Esther van Kleef¹  Nantasit Luangasanatip⁴  Marc J Bonten¹  Ben S Cooper⁶ 

[1] Julius Centre for Health Sciences and Primary Care, University Medical Center Utrecht;Modelling and Economics Unit, National Infection Service, Public Health England;Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University;Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine;Department of Medical Microbiology, University Medical Centre Utrecht;Nuffield Department of Medicine, University of Oxford

关键词: mathematical modelling;    nosocomial infections;    hospital infection control;    Clostridium difficile;    Staphylococcus aureus;    MRSA;    hand hygiene;    antibiotic resistance;   

DOI  :  10.12688/wellcomeopenres.11033.2

学科分类：内科医学

来源: Wellcome

【 摘 要 】

Background: Large reductions in the incidence of antibiotic-resistant strains ofStaphylococcus aureus andClostridium difficile have been observed in response to multifaceted hospital-based interventions. Reductions in antibiotic-sensitive strains have been smaller or non-existent. It has been argued that since infection control measures, such as hand hygiene, should affect resistant and sensitive strains equally, observed changes must have largely resulted from other factors, including changes in antibiotic use. We used a mathematical model to test the validity of this reasoning.Methods: We developed a mechanistic model of resistant and sensitive strains in a hospital and its catchment area. We assumed the resistant strain had a competitive advantage in the hospital and the sensitive strain an advantage in the community. We simulated a hospital hand hygiene intervention that directly affected resistant and sensitive strains equally. The annual incidence rate ratio (IRR) associated with the intervention was calculated for hospital- and community-acquired infections of both strains.Results: For the resistant strain, there were large reductions in hospital-acquired infections (0.1 ≤IRR ≤ 0.6) and smaller reductions in community-acquired infections (0.2 ≤IRR ≤  0.9). These reductions increased in line with increasing importance of nosocomial transmission of the strain. For the sensitive strain, reductions in hospital acquisitions were much smaller (0.6 ≤IRR ≤ 0.9), while communityacquisitions could increase or decrease (0.9 ≤IRR ≤ 1.2). The greater the importance of the community environment for the transmission of the sensitive strain, the smaller the reductions.Conclusions: Counter-intuitively, infection control interventions, including hand hygiene, can have strikingly discordant effects on resistant and sensitive strains even though they target them equally, following differences in their adaptation to hospital and community-based transmission. Observed lack of effectiveness of control measures for sensitive strains does not provide evidence that infection control interventions have been ineffective in reducing resistant strains.

【 授权许可】

CC BY