Infectious Complications in Metabolic and Bariatric Surgery: A Comprehensive Narrative Review of Pathophysiology, Prevention, and Management

Background: Metabolic and bariatric surgery is an established therapeutic option for severe obesity and obesity-related medical problems. Although minimally invasive techniques and enhanced recovery pathways have reduced postoperative morbidity, infectious complications remain clinically relevant because they may lead to readmission, reoperation, prolonged antimicrobial therapy, and mortality. Methods: We conducted a narrative review of the literature on infectious complications after metabolic and bariatric surgery. Evidence was synthesized across five clinically relevant domains: host-related pathophysiology, microbial epidemiology, preoperative optimization, antimicrobial prophylaxis and pharmacokinetic considerations, and diagnosis and management of postoperative infectious complications. Results: Patients with obesity present specific infection-related vulnerabilities, including chronic low-grade inflammation, altered immune responses, impaired tissue oxygenation, obesity-related medical problems, and procedure-specific risks. Contemporary prevention relies on multidisciplinary preoperative optimization, appropriate skin antisepsis, weight-based antimicrobial prophylaxis, intraoperative redosing when indicated, and adherence to enhanced recovery principles. Anastomotic leaks and intra-abdominal abscesses represent the most severe organ/space infections and require early recognition, source control, antimicrobial therapy, nutritional support, and coordinated surgical, radiological, and endoscopic management. Conclusions: Infectious complications after metabolic and bariatric surgery result from the interaction between host physiology, microbial factors, pharmacological considerations, and surgical technique. A structured approach integrating prevention, early diagnosis, and multidisciplinary management may improve outcomes. Further bariatric-specific studies are needed to strengthen the evidence base for several preventive and therapeutic strategies.