Vancomycin in the treatment of adult intra-abdominal infections: do we have strong evidences? Song Liu, Meng Wang, Wenxian Guan Department of General Surgery, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Nanjing 210008, China Abstract: The management of intra-abdominal infections (IAIs) primarily includes adequate antimicrobial therapy and appropriate source control. Vancomycin is a fundamental and most effective antimicrobial agent. The aim of this study is to search and evaluate the quality of clinical evidences regarding the exclusive use of vancomycin for the management of adult IAIs. For this purpose, we first summarized the recommendations on exclusive use of vancomycin in adult IAIs from six leading guidelines and excavated the relevant supporting references. We subsequently conducted a literature search to screen eligible clinical studies in this field for possible systematic review. Our investigation demonstrates that the exclusive use of vancomycin is recommended in restricted indications, that is, IAIs caused by Enterococcus spp. or methicillin-resistant Staphylococcus aureus. However, the supporting references in the guidelines are more subjective instead of objective, which mainly originate from experts’ personal experiences or from the therapeutic efficacy of vancomycin in other types of infections rather than in IAIs. Furthermore, our literature search fails to find high-level evidence. In conclusion, current low-level evidences are inadequate to elicit strong recommendations on the exclusive use of vancomycin in the treatment of adult IAIs. Our study would be helpful for the rational use of vancomycin and deceleration of the emerging vancomycin resistance rates. Keywords: intra-abdominal infection, vancomycin, guideline, anti-infective agents