The association between acute gastrointestinal injury and mortality in elderly patients with gram-positive bacterial bloodstream infection in the intensive care unit: a retrospective 7-year study from a research hospital in China

Background Gram-positive bacterial bloodstream infections (GPB-BSI) are associated with high mortality in elderly ICU patients, yet prognostic factors remain understudied. Acute gastrointestinal injury (AGI), a common complication in critical illness, may exacerbate outcomes through gut-organ crosstalk. This study investigates the prognostic impact of AGI severity on 30-day mortality in elderly ICU patients with GPB-BSI. Methods A single-center retrospective cohort study analyzed 117 ICU patients aged ≥60 years with culture-confirmed GPB-BSI (2018–2024). Data on demographics, microbiology, comorbidities, organ dysfunction, and antimicrobial therapy were collected. Multivariable Cox regression and ROC analyses assessed associations between AGI, clinical variables, and mortality. Results The 30-day mortality rate was 50.4% (59/117). AGI severity independently predicted mortality: Grades I-II (aHR = 2.80, 95% CI = 1.05 ~ 7.46) and Grades III-IV (aHR = 6.89, 95%CI = 2.34 ~ 20.29). A combined SOFA-AGI score improved prognostic accuracy compared to SOFA score(AUC = 0.749 vs 0.729). Coagulase-negative staphylococci (60.3%) dominated isolates, predominantly hospital-acquired (79.4%) and catheter-related (47.0%). High resistance to penicillins (92.1%), fluoroquinolones (79.4%), and macrolides (77.0%) contrasted with retained susceptibility to linezolid (96.8%), tigecycline (92.9%), and vancomycin (94.4%). Conclusion AGI severity is an independent predictor of mortality in elderly GPB-BSI patients. The diagnostic accuracy for mortality improves when gastrointestinal dysfunction assessment is incorporated into the SOFA score. These findings underscore the critical need for enhanced clinical attention to gastrointestinal function protection in geriatric critical ill patients.