Antibiotic resistance pattern and clinical outcomes in acute cholecystitis: 567 consecutive worldwide patients in a prospective cohort study

Introduction: Postoperative complications for cholecystitis and cholelithiasis are important causes of intra-abdominal infections (IAIs). There have been no previous reports on intra-abdominal bacteriology in complicated IAIs due to acute cholecystitis (AC). Material and methods: The data came from two prospective multicenter observational cohort studies (CIAO: the "Complicated Intra-Abdominal infection Observational" study and CIAOW: the "Complicated Intra-Abdominal infection Observational World" study) which involved 116 medical institutions worldwide with consecutive patients who underwent surgery, interventional drainage or conservative treatment for AC. Results: Of 567 patients, there were 291 males (51.3%). The mean and median age were 62.5 and 64 years respectively. 546 (96.3%) had community-acquired and 21 (3.7%) patients had health-care-associated infections. 267 bacteria were isolated, 21 (7.8%) were resistant bacteria. No resistant Fungi or Anaerobes were isolated. 4 out of the 21 resistant bacteria were health-care-associated. Multivariate analysis demonstrated health-care associated infection (p = 0.03), inadequacy of empiric antimicrobial therapy (p = 0.003) and recent antimicrobial therapy (p < 0.0001) to be factors associated with resistant bacteria. The factors associated with mortality were presence of generalized peritonitis (p < 0.0001) and inadequate source control (p = 0.018). The factors associated with ICU admission were severe sepsis (p < 0.0001), generalized peritonitis (p = 0.001), concomitant malignancy (p = 0.037), inadequate source control (p = 0.025), delay in initial intervention (p < 0.0001) and age over 70 years (p = 0.025). Conclusion: The number of infection caused by Extended Spectrum Beta-Lactamase bacteria (ESBL+) and Klebsiella pneumoniae Carbapenemase-producer bacteria (KPC+) were common in acute cholecystitis and in community-acquired infections. An adequate empirical antimicrobial therapy was fundamental to reduce bacterial resistance and to improve outcomes.