Switch to second-line antibiotic therapy was defined as the addition of one or more parenteral antibiotics to the initial antibiotic regimen

or as a complete or partial switch of the initial antibiotic regimen to another parenteral antibiotic regimen. Unscheduled additional abdominal surgeries were taken into account if they occurred 2 or more days after the primary surgical procedure and were related to poor primary source control. Secondary procedures were not considered in the analysis when there was a mention of other reasons (i.e. technical issues or hemorrhage) that might have led to re-operation. First-line empiric antibiotic therapy was defined as appropriate if all isolated bacteria were sensitive to at least one of the antibiotics administered Quisinostat research buy in patients with documented positive intra-abdominal swabs or blood cultures. Alternatively, in patients with negative or no cultures, empiric therapy was deemed as appropriate when the selected regimen covered enteric gram-negative aerobic and anaerobic bacteria and drug dosing was adequate, find more according to current guidelines [1]. Antibiotic regimens not fulfilling the above criteria were defined as inappropriate. Leucocytosis was defined by a white blood cell (WBC) count >12,000/mm3. Leukopenia was defined as a WBC count <4000/mm3. Cost analysis A estimate of the cost of antibiotics was performed by multiplying the number of antibiotic

days by the unit price of that antibiotic and by the number of per day doses. The overall cost of antibiotic treatment for each patient was the sum of costs calculated for all parenteral antibiotics received by the patient during the hospitalization period. The unit price of antibiotics was based on official ex-factory prices per unit in Italy [12]. Laboratory tests, instrumental tests, and specialists’ consultancies utilization were directly recorded and their costs were assessed by referring to fees for providers of specialist services recognized by

the Italian National Health Service (I-NHS). Costs related to primary surgical procedures were not included in analysis, as we assume they were independent Lepirudin of the adopted antibiotic therapy. Other direct costs, including personnel, ordinary maintenance and hotel costs, were indirectly estimated by using Diagnosis-Related Group’s tariffs per admission provided to hospitals by the I-NHS. Specifically, this estimate was based on the acknowledged over-threshold per hospital day tariff, which is the per day cost to hospitals for length of stay prolonged over an a priori defined threshold (i.e. a tariff applicable to length of stay statistically considered as outliers), assuming that by subtracting the average costs of specialist services provided from this tariff, an acceptable proxy of the general cost Salubrinal manufacturer sustained for patient management could be obtained. Costs were expressed in Euro values at the time they were incurred (year 2009 values).