Addressing the threat of AMR in Norway: optimising antibiotic prescribing and microbiology testing in hospitals

Abstract

Increasing antimicrobial resistance rates are recognised as a global public health threat and many efforts are being undertaken to curb this development. One important measure is to optimise the use of antibiotics and microbiology testing, which is of significance to target antibiotic therapy. The aim of this thesis was to gain new knowledge on what factors influence antibiotic prescribing practices in Norwegian hospitals, highlighting the use of microbiology tests. This knowledge will be applied to outline targeted interventions for optimised antibiotic prescribing in Norwegian hospitals. The aim was addressed in three separate, but interconnected studies. First, factors influencing antibiotic prescribing practices among hospital physicians were studied, using an explorative qualitative study design and semi-structured interview methodology. The same design and methodology was applied in study 2, to investigate communication barriers between microbiology laboratories and clinical units and how they can be addressed. In study 3, a multi-centre cohort study design was used to study microbiology test ordering practices in hospitals and how microbiology test results are used to inform antibiotic decision-making. Main findings were that colleagues, in particular ID physicians, the national guideline on antibiotics, microbiology test results, training, patient assessment and informal leaders influenced antibiotic prescribing practices in hospitals. The availability of the national antibiotic guideline was impaired, training was mainly informal, the hospital leaders were absent in promoting antibiotic prescribing policies and delayed availability of microbiology test results was perceived as a barrier for targeting antibiotic treatment. The main barrier to communication between clinical units and the microbiology laboratories was disruption related to logistics of specimen, information on request forms, verbal reporting of test results and information transfer between poorly integrated IT systems. Communication was also challenged by lack of insight into each other’s area of expertise and limited provision of laboratory services. Mean compliance with microbiology testing recommendations in the antibiotic guideline was 89%, but a substantial proportion of additional testing was performed beyond the recommendations. Altogether, 298/606 (49%) of patients with lower respiratory tract infections had urine cultures and 42/194 (22%) of patients with urinary tract infections had respiratory tests. Some microbiology tests had poor performance characteristics and only half of the applicable test results were used for therapy guidance. As a result, only 9% (63/672) of test results informed antibiotic decision-making. These findings highlight the importance to perform studies on antibiotic prescribing practices and use of microbiology tests in specified contexts to identify targeted interventions for optimisation of antibiotic use in each context. A national Antimicrobial Stewardship (AMS) programme may be a suitable organisational framework to implement these interventions. This thesis showed that ID physicians have a crucial role to play in hospital AMS teams as they were trusted colleagues in infection management. It also identified that hospital AMS programmes should include interventions to improve the use of microbiology tests through a review of all the steps of the diagnostic pathway. Microbiologists can facilitate this review and should preferably be members of the AMS teams. Furthermore, the AMS programmes should establish educational programmes on infection management and microbiology for clinical- and microbiology laboratory staff. Finally, the thesis identified a need for interventions at the national level. It must be ensured that the national antibiotic guideline remains relevant by securing its availability on several platforms and by regular updates. Hospital leaders should be made accountable for implementing AMS programmes locally and responsible for reaching national targets to optimise antibiotic use in Norwegian hospitals.