Surveillance of Clostridioides difficile on hospital admission and outpatient antibiotic use in Germany-a 9 year ecological analysis.

Background: Antibiotic consumption is considered an important risk factor for Clostridioides difficile infection (CDI). This ecological analysis investigates the influence of outpatient antibiotic prescriptions in statutory health insurance (SHI) on the admission prevalence of CDI in German hospitals participating in voluntary CDI surveillance through the hospital infection surveillance system (Krankenhaus-Infektions-Surveillance-System; KISS).

Methods: The annual CDI admission prevalence of a hospital at the federal state level was associated with the outpatient antibiotic consumption of the corresponding federal state. The quantification of outpatient antibiotic prescriptions was determined as the average DDD per 1000 insured persons per day. The risk factors for CDI on hospital admission included the annual consumption of the eight substance groups aminopenicillin combinations/staphylococcal penicillins, basic penicillins, cephalosporins, quinolones, lincosamides/macrolides, nitrofurantoin/fosfomycin/nitroxoline, sulphonamides/trimethoprim and tetracyclines, the type of care provided by the hospital, and the calendar year, and were examined using multivariable regression analyses (generalized estimating equations models).

Results: Between 2011 and 2019, the number of outpatient antibiotic prescriptions decreased from 13.9 to 10.4 DDD per 1000 insured persons per day (-25%), and the CDI admission prevalence decreased from 0.22 to 0.12 per 100 patients (-45%). Basic penicillins and cephalosporins were identified as risk factors for increased CDI admission prevalence, while nitrofurantoin/fosfomycin/nitroxoline and sulphonamides/trimethoprim were associated with decreased CDI admission prevalence.

Conclusions: A decrease in outpatient antibiotic prescriptions with known risk of developing CDI was associated with a decrease in hospital CDI admission prevalence. Our ecological analysis indicates that rational and restrained antibiotic use in the outpatient setting may reduce the incidence of CDI in the population requiring inpatient treatment.