Background: Post-operative infection is a common complication following abdominal surgery. The two most common infections are secondary peritonitis and surgical site infections, which lead to increased perioperative morbidity, prolonged hospitalization, higher mortality rates, and increased treatment costs. In addition to surgical procedures, treatment is based on effective antibiotic therapy. Due to increasing antimicrobial resistance, the correct use of antimicrobials is becoming more complex. Many initiatives call for the implementation of an antimicrobial stewardship (AMS) programme to optimize anti-infective therapy. The review article summarizes current recommendations in anti-infective therapy of post-operative peritonitis and surgical site infections and highlights the importance of an AMS programme in abdominal surgery. Summary: Larger studies evaluating the benefit of AMS in abdominal surgery are lacking. However, national and international guidelines have formulated appropriate recommendations for the rational use of antibiotics in post-operative peritonitis and surgical site infections. The rate of post-operative infections can be significantly reduced by perioperative antibiotic prophylaxis. The increase in multidrug-resistant bacteria complicates anti-infective therapy for post-operative infections. Analysis of local susceptibility patterns helps choose an adequate empiric therapy. A high rate of extended-spectrum beta-lactamase-producing bacteria may necessitate the use of other reserve antibiotics in addition to carbapenems, which are approved for the treatment of complicated intra-abdominal infections. A key role for the AMS team is the subsequent de-escalation of antibiotic therapy which limits the use of unnecessary broad-spectrum antibiotics. Key Messages: The increase in multidrug-resistant bacteria poses challenges for abdominal surgery. Post-operative infections should be treated by an interdisciplinary team of surgeons and specialists for AMS.

Background Risk factors for the development of Whipple's disease (WD) are largely unknown. Case reports, case series, and reviews suggest immunosuppressive therapy as a potential triggering factor in WD. The low incidence of WD and non-specific symptoms at disease onset contribute to the frequent delay of diagnosis. We describe our centre´s experience on differences in the clinical presentation of patients with classic WD compared to patients with “masked” WD because of immunosuppressive therapy. Methods In this retrospective case series, 8 patients were included. Diagnosis of WD was confirmed by histological staining of duodenal biopsies revealing T. whipplei within foamy macrophages or by PCR- based detection of specific T. whipplei DNA. Clinical manifestations, laboratory data, and medication have been recorded over a period of 19 years. Subgroup analyses for the two different variants of WD were performed. Results Seven of eight patients were initially diagnosed with rheumatic disease (polyarthritis, polymyalgia rheumatica). One patient was correctly diagnosed at the beginning without any medication. Three patients were on immunosuppressive therapy and being treated with disease-modifying drugs (DMARDs), three patients were receiving low-dose cortisone in combination with non-steroidal anti- inflammatory drugs (NSAIDs), and one patient was receiving NSAIDs only. All patients presented with increased parameters of inflammation and with clinical and/or laboratory signs of a malabsorption. From the onset of first symptoms, diagnosis of WD took a median of 36 months (range: 6–120 months). The time between onset of joint complaints and onset of gastrointestinal symptoms was 36 months (range: 0–117 months). WD patients receiving immunosuppressive therapy, compared to those not receiving it, had a longer duration of gastrointestinal symptoms (12 months versus 6 months) and reported a greater weight loss (20,3 kg versus 7,8 kg) up to diagnosis of WD. Conclusions Immunosuppressive drugs may delay the diagnosis of WD and prolong the course of T. whipplei infection with deterioration of clinical symptoms. If a patient with rheumatic complaints develops gastrointestinal symptoms, diagnosis of WD should be considered and proper diagnostic investigation carried out.

Background/Objectives: Obstruction of the biliary duct may be caused by various conditions ranging from chronic inflammation to neoplasia, including cholangiocarcinoma (CCA). While the definite histological diagnosis of intrahepatic lesions is relatively straightforward, the diagnostic workup of biliary duct stenosis can be challenging, despite the availability of novel tools for intraductal diagnosis. This proof-of-principle study aimed to investigate whether microRNAs (miRNAs) from bile duct stents may be used as biomarkers to differentiate between various bile duct diseases. Methods: For this purpose, we included 100 patients with one or more bile duct stents for various reasons, including malignant disease (n = 40), stenosis due to liver transplantation or surgery (n = 60), and cholangitis (n = 42). During endoscopic retrograde cholangiography, the stents were collected, and miRNA analyses were performed to evaluate miR-16, miR-21, and miR-223. Results: All studied miRNAs were successfully detected from the specimens obtained from the bile duct stents and were comparable in different stents from the same subjects. Following normalization, significant increases in miR-16, -21, and -223 levels were identified in patients with cholangitis compared to specimens from a non-inflammatory cohort. However, when comparing the data from patients in the malignant and non-malignant cohorts, the individual levels of miR-16, miR-21, and miR-223 showed high variation, without reaching a statistically significant difference. Conclusions: In summary, bile duct stents can be considered as potential sources of intraductal biomarkers, specifically miRNAs. Further profiling and validation analyses are necessary to identify the most appropriate miRNA targets for differentiating bile duct diseases.