(1) Background: Elizabethkingia spp. is an emerging nosocomial pathogen which causes mostly blood stream infection and nosocomial pneumonia. Among Elizabethkingia species, Elizabethkingia anophelis is the major pathogen, but misidentification as Elizabethkingia meningoseptica is a common problem. Elizabethkingia also possesses broad antibiotic resistance, resulting in high morbidity and mortality of the infection. The aim of our study was to review Elizabethkingia intra-abdominal infections and investigate resistance mechanisms against TMP/SMX in Elizabethkingia anophelis by whole genome sequencing. (2) Methods: We retrospectively searched records of patients with Elizabethkingia intra-abdominal infection between 1990 and 2019. We also conducted whole genome sequencing for a TMP/SMX-resistant Elizabethkingia anophelis to identify possible mechanisms of resistance. (3) Results: We identified a total of nine cases of Elizabethkingia intra-abdominal infection in a review of the literature, including our own case. The cases included three biliary tract infections, three CAPD-related infection, two with infected ascites, and two postoperation infections. Host factor, indwelling-catheter, and previous invasive procedure, including surgery, play important roles in Elizabethkingia infection. Removal of the catheter is crucial for successful treatment. Genomic analysis revealed accumulated mutations leading to TMP/SMX-resistance in folP. (4) Conclusions: Patients with underlying disease and indwelling catheter are more susceptible to Elizabethkingia intra-abdominal infection, and successful treatment requires removal of the catheter. The emerging resistance to TMP/SMX may be related to accumulated mutations in folP.