5) 25 (37.8) <0.05  Cancer 8 (4.1) 8 (12.1) <0.05  Anemia 6 (3.1) 10 (15.2) <0.05  Liver cirrhosis 1 (0.5) 0 (0) NS  Renal failure 1 (0.5) 1 (1.5) NS  End stage renal failure 2 (1.0) 0 (0) NS  Coagulopathy 2 (1.0) 0 (0) Metformin nmr NS  Immunosuppression 1 (0.5) 1 (1.5) NS Primary surgical intervention site, n (%)        Appendix 132 (68.0) 30 (45.4) <0.05  Lower

GI tract 23 (11.8) 28 (42.4) <0.05  Upper GI tract 10 (5.1) 3 (4.5) NS  Gall-bladder 13 (6.7) 1 (1.5) NS  Peritoneal abscess 13 (6.7) 3 (4.5) NS  Other 3 (1.5) 1 (1.5) NS Surgical approach, n (%)        Laparoscopy 111 (57.2) 24 (36.3) <0.05  Laparotomy 76 (39.2) 40 (60.6) <0.05  Percutaneous 7 (3.6) 2 (3.0) NS Antibiotic treatment, n (%)        Monotherapy 101 (52.1) 46 (69.7) <0.05  Combination therapy 93 (47.9) 20 (30.3) <0.05 Illness severity markers, n (%)        Parenteral nutrition 27 (13.9) 25 (37.8) <0.05  Central

venous catheter Selleckchem Proteasome inhibitor 16 (8.2) 24 (36.3) <0.05  Antifungal drugs 12 (6.2) 16 (24.2) <0.05  Enteral nutrition 10 (5.2) 12 (18.2) <0.05  Invasive mechanical ventilation 6 (3.1) 14 (21.2) <0.05 ICU admission, n (%) 6 (3.1) 18 (27.3) <0.05 Mortality rate, n (%) 0 (0) 6 (9.1) NS GI, gastrointestinal; ICU, intensive care unit; NS, not significant; SD, standard deviation. The majority of patients who experienced clinical failure (99.6%) switched to second-line antibiotic therapy, 12 (18.2%) underwent unscheduled additional surgeries and 6 (9.1%) died. Second-line antibiotic therapy included switching to entirely different antibiotics in 63.6% of cases and addition of one or more drugs to the initial antibiotic

regimen in 36.3% of cases. Reasons for switching therapy were clinical ineffectiveness in 63.6% of patients, microbiologic resistance in 9% and was unreported in 24.2% Amino acid of patients. Second-line regimens involved meropenem (25.7%), ertapenem (21.2%), tygecicline (19.6%) and glycopeptides (10.6%). In-hospital charges by therapeutic outcome Patients who failed antibiotic therapy received an average of 8.2 additional days of antibiotic therapy and spent 11 more days in hospital compared with patients who responded to first-line therapy (both p < 0.05 vs. clinical success group). Furthermore, they incurred €5592 in additional hospitalization costs (2.88 times the cost associated with clinical success) with 53% (€2973) of the additional costs attributable to antibiotic therapy (Figure  3). All of the other contributors to hospitalization costs were significantly higher in the clinical failure group (Figure  3). Figure 3 Total hospitalization costs per patient, stratified by therapeutic outcome. Other direct costs category includes personnel, ordinary maintenance and hotel costs. *p < 0.05 vs. clinical failure group.