Patients admitted to the hospital with acute infections are often treated with intravenous (IV) antibiotics. Around 70% of these infections fall into three categories: respiratory tract infections, urinary tract infections, and cellulitis. A Danish study found that 76% of patients admitted with suspected community-acquired pneumonia and treated with antibiotics received them intravenously. Based on an extrapolated estimate from an unpublished local survey, approximately 50,000 patients in Denmark are admitted each year for infections and treated with IV antibiotics. The average hospital stay for these patients is 5.9 days, resulting in a total of 295,000 hospital days annually, accounting for about 7% of total hospital admissions in Denmark. This represents an annual cost of 2.3 billion DKK. While some patients need hospitalization due to their overall health or other serious conditions, others remain hospitalized primarily to receive IV antibiotics.

Expanding the use of oral antibiotics in emergency departments should be pursued only if it can demonstrate comparable efficacy and safety to IV administration. Therefore this study will investigate the efficiency of primarily oral antibiotics in acutely admitted patients with proven or suspected infections. Additionally, the investigators will evaluate the safety of oral regimen for these patients.

Patients admitted to the hospital with infections are often treated with intravenous antibiotics. The rationale for using intravenous antibiotics includes eliminating the risk of reduced absorption, achieving higher serum concentrations, and the fact that many broad-spectrum antibiotics (such as cephalosporins and carbapenems) are not available in oral form. However, intravenous antibiotics also have drawbacks, such as the risk of catheter-related infections, challenges in home-based treatment, and difficulty switching to oral antibiotics unless microbiological results are definitively positive. Prolonged hospital stays associated with intravenous antibiotic treatment lead to economic burdens, increased risk of hospital-acquired infections, and significant functional decline, especially in older patients.

In recent decades, many studies have explored the possibility of fully or partially replacing intravenous antibiotics with oral antibiotics for certain infections.

In this study, the investigators will examine the safety and efficacy of primarily oral antibiotic regimens in patients with confirmed or suspected infections admitted to the emergency department. The study is an open-label, prospective, randomized controlled trial. Participants will be randomly assigned to receive either standard intravenous antibiotic treatment according to Danish guidelines or oral antibiotic treatment based on tailored recommendations developed by microbiologists and infectious disease specialists at participating sites, in accordance with local guidelines.

The study has two primary outcomes: 1) Efficacy-measured as the number of days alive outside the hospital within 30 days after randomization, and 2) Safety-measured by mortality or the need for vasopressors within 30 days after randomization. A total of 4,000 patients will be needed to address both primary outcomes.

Aim: The trial aims to investigate the safety and efficacy of oral antibiotic administration compared to intravenous antibiotic administration in patients referred to the emergency department with suspected or diagnosed bacterial pneumonia, urinary tract infection and cellulitis.

Inclusion Criteria:

• Suspected respiratory tract infection, urinary tract infection, or cellulitis by the attending physician
• Planned or initiated intravenous antibiotic treatment

Exclusion Criteria:

• if received more than two doses of intravenous antibiotics;
• systolic blood pressure <90 mmHg;
• nausea and/or vomiting in more than one short-term instance during the last 2 days;
• suspected significantly reduced gastrointestinal absorption;
• confirmed plasma-lactate > 2;
• pregnant or nursing;
• unable to give informed consent;
• severe immunodeficiency;
• urgent vital treatment needed.