Antimicrobial Resistance Differs Significantly Between Hospitals: The Advantage of a Regional Analysis of Blood Culture Isolates

Background: Sepsis is a life-threatening syndrome caused by a dysregulated host response to infection. In case of a suspected case of sepsis empirical antimicrobial treatment is needed. The choice of empiric treatment is primarily an “informed guess” based on national guidelines, but also on knowledge of local and regional resistance of typically isolated microorganisms.
Materials/methods: In this study, bug/drug combinations were analysed of all bacterial blood culture isolates from patients of all 14 secondary and tertiary care hospitals in the Northern Netherlands detected in the last 15 years (between 2002 to 2016). Only first isolates were selected and included by using a novel selection algorithm, based on the M39-A4 guideline of CLSI, taking into account isolate-specific resistance of key antibiotics which were chosen based on the genus and Gram stain. Subsequently, we compared the resistance of blood culture isolates between hospitals using a full-region approach.
Results: Using the novel method, nearly 10% more bacterial strains were included compared to the CLSI guideline, resulting in a total of about 123,000 instead of 105,000 isolates. We show significant differences in antimicrobial resistance between hospitals, even when comparing the resistance of the same microbial species. Importantly, prevalence of Methicillin Resistant Staphylococcus aureus (MRSA) has increased from 0.3% in 2002 to 1.4% in 2016 and Quinolone and Aminoglycoside Resistant Enterobacteriaceae (QARE) from 0.2% in 2002 to 2.4% in 2016. Nevertheless, their prevalence remains lower compared to neighbouring countries.
Conclusions: Empiric therapy for patients with septicaemia might be improved in single hospitals, by analysing the regional inter-institutional epidemiology of bacteriaemic isolates comprising the correspondent resistance. It has been shown that there are major local epidemiological differences in microbial resistance, but a regional homogeneity in microbial prevalence. This allows for a more specific therapy of first choice using regional or even local hospital protocols, rather than using general national guidelines. We recommend to analyse bacterial surveillance and prevalence of resistance in a full-area approach instead of single hospitals or the national level.