A Case of Weissella confusa Isolated from Blood of a Patient with Coronary Heart Disease Complicated with Gastrointestinal Bleeding

INTRODUCTION: W. confusa has been known to cause various human infections. It is naturally resistant to vancomycin and is difficult to identify using traditional methods, which may lead to misidentification and delay treatment. CASE PRESENTATION: We present a case of a 42-year-old male patient with gastrointestinal bleeding and coronary heart disease who developed sepsis caused by Weissella confusa. The patient’s blood cultures showed the presence of gram-positive coccobacilli, later identified as W. confusa through matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). Antimicrobial susceptibility testing revealed that W. confusa had low minimum inhibitory concentrations (MICs) for some drugs (eg, ampicillin) and higher MICs for others (eg, cefotaxime). Empirical treatment with vancomycin was initially started, but after obtaining the identification and susceptibility results, the treatment was switched to meropenem combined with daptomycin, resulting in a successful outcome. CONCLUSION: Weissella confusa bacteremia is relatively rare, and accurate pathogenic diagnosis is essential for effective clinical treatment.