The Microbiological Spectrum and Antibiotic Resistance in Acute Acalculous and Calculous Cholecystitis: A Seven-Year Study in a Tertiary Center

<i>Background and Objectives</i>: Acute acalculous cholecystitis (AAC) is rare, mostly in older males, with cardiovascular diseases, diabetes, critical illness, or systemic infection. Antibiotherapy before or after cholecystectomy is important for preventing septic shock and postoperative infections. Increasing antibiotic resistance was recently noted and can complicate antibiotherapy. <i>Materials and Methods</i>: A retrospective study of all patients who underwent cholecystectomy between 2018 and 2024 in the Clinical Emergency Hospital of Craiova was performed. The etiology of AAC, complications, hospitalization duration, mortality, positive bile cultures, and in vitro antibiotic resistance were analyzed. <i>Results</i>: A total of 802 calculous and 54 AAC were recorded. Patients with AAC were predominantly males (OR = 1.767, <i>p</i> = 0.043) with diabetes (OR = 2.049, <i>p</i> = 0.014) and were older (66.6 ± 13.2 vs. 61.4 ± 15.6, <i>p</i> = 0.014). Mortality was significantly higher in AAC (18.5 vs. 3.6%, OR = 6.058, <i>p</i> < 0.001), with longer hospitalization (mean 9.7 vs. 8.4 days) and more perforation. Positive bile cultures were recorded in 60.5-66.2% of cases, with a similar etiology in both forms of acute cholecystitis (mostly Gram-negative species, <i>Enterococcus,</i> and <i>Staphylococcus</i>); 10 ESBL <i>Escherichia coli</i> and <i>Klebsiella</i> strains, 11 <i>Staphylococcus aureus</i> MRSA, and 1 <i>Enterococcus</i> VRE strain were recorded. Antibiotic susceptibility in vitro was similar in both AAC and calculous cholecystitis. Significant resistance to cephalosporins and quinolones was recorded; the lowest resistance was noted for amikacin, carbapenems, chloramphenicol, colistin (Gram-negative bacteria), and vancomycin. <i>Conclusions</i>: AAC was encountered in older males with diabetes, with a higher rate of complications and in-hospital mortality. Bile cultures were positive in 60.5-66.2%, predominantly with Gram-negative, <i>Enterococcus</i>, and <i>Staphylococcus</i> species. Significant in vitro resistance to cephalosporins and quinolones was found.