An antimicrobial stewardship intervention (consisting of education, motivating opinion leaders, audit and feedback) in patients hospitalized with community-acquired pneumonia resulted in 27 percent reduction in broad-spectrum antibiotic use, without compromising patient outcome. These findings were reported by Inger van Heijl and Valentijn Schweitzer who both received their PhD titles for their (partly joined) research on methodology and execution of antimicrobial stewardship strategies in hospitalized patients with CAP.

Antibiotic resistance is a global health threat, with overuse of antibiotics being one of its main drivers. Antimicrobial stewardship is a strategy aimed at optimizing antibiotic use and its primary goal is to optimize clinical outcomes while minimizing unintended consequences of antimicrobial use (in particular emergence of resistance). In hospitals, a substantial proportion of antibiotics is prescribed for treatment of community-acquired pneumonia (CAP), often without adhering to existing treatment guidelines. Therefore, improving guideline adherence in CAP is an appealing target of antimicrobial stewardship. However, both effectiveness and safety of antimicrobial stewardship interventions in CAP have not been unequivocally demonstrated in well-controlled studies.

Improving interventions

The PhD dissertations by Valentijn Schweitzer and Inger van Heijl (both Department Epidemiology of Infectious Diseases, Julius Center, UMC Utrecht) describe studies aimed at evaluating and improving antimicrobial stewardship interventions. They also investigated whether antimicrobial stewardship is effective in reducing broad-spectrum antibiotic use in patients hospitalized with moderate-severe CAP without compromising patient outcomes.

Less antibiotic use

Valentijn Schweitzer and Inger van Heijl investigated a multifaceted antimicrobial stewardship intervention targeting physicians (by education, motivating local opinion leaders, prospective audit and feedback of antibiotic use) in a randomized trial in 12 Dutch hospitals on the correct prescription of antibiotics in 4,084 patients with moderate-severe CAP hospitalized at a non-ICU ward. The intervention resulted in 27 percent reduction of treatment days (4.8 versus 6.6 days) with broad-spectrum antibiotics as compared to the control period without intervention. There was no difference in 90-day overall mortality between intervention and control (10.8 en 10.9 percent, respectively).

According to the investigators, the results of this study suggest that more patients with moderate-severe CAP can be safely treated with narrow-spectrum antibiotics. This approach is expected to contribute to a reduction of antimicrobial resistance.

Community-acquired pneumonia

CAP is a lower respiratory tract infection with high morbidity and mortality, which predominantly affects elderly patients. The most common pathogens causing CAP are Streptococcus pneumoniae and Haemophilus influenzae, but in the majority of patients no pathogen is identified. It is difficult to reliably determine the causative pathogen of CAP at the time of presentation. Therefore, empirical treatment is based on the concept that the most severely ill patients require immediate broad-spectrum antibiotics covering the great majority of possible pathogens while in non-severe patients there is room to start with narrow-spectrum antibiotics and wait for clinical response and/or diagnostic test results.

PhD defenses

• Inger van Heijl (1986, Velp) defended her PhD thesis on November 3, 2020 at Utrecht University. The title of her thesis was “Antibiotic Stewardship in Community-acquired pneumonia”. Supervisor was prof. dr. Marc Bonten (Department Epidemiology of Infectious Diseases, UMC Utrecht) and co-supervisors were dr. Paul van der Linden and dr. Wendelien Dorigo-Zetsma (both Tergooi Hospital, Hilversum). In April 2020, she started her training in hospital pharmacy at St. Antonius Hospital in Nieuwegein.
• Valentijn Schweitzer (1987, Beverwijk) defended his PhD thesis on November 3, 2020 at Utrecht University. The title of his thesis was “Improving community-acquired pneumonia treatment by antimicrobial stewardship”. Supervisor was prof. dr. Marc Bonten (Department Epidemiology of Infectious Diseases, UMC Utrecht) and co-supervisors were dr. Edwin Boel (Department of Medical Microbiology) and dr. Jan Jelrik Oosterheert (Department of Infectious Diseases). In 2018, Valentijn Schweitzer started his training to become a medical microbiologist at UMC Utrecht and St. Antonius Hospital, Nieuwegein.