A method for determining a number of Nosocomial Infection Markers (NIMs) corresponding to a number of distinct hospital-acquired infections, the method comprising: receiving from a database patient hospitalization data associated with at least one patient, wherein the patient hospitalization data is formed from combinations of patient admit, discharge and transfer data; microbiology and microbiology related test data; and antimicrobial dispensing data; calculating at a computer (101, 101a, 101b) from the patient hospitalization data a number of specimens with non-duplicate hospital isolates (SNDHI) markers for each patient hospitalization wherein, the number of SNDHI is calculated by: eliminating duplicate isolates; eliminating isolates associated with specimen contamination, surveillance, and non-infected clinical states; identifying hospital isolates, comprising identifying isolates obtained from specimens collected from a patient who has been a hospitalized patient one or more times within a period of days or hours prior to specimen collection and/or after the patient has been in the hospital for a period of time; and calculating the sum of SNDHIs; calculating from the patient hospitalization data, antibiotic utilization criteria values for each patient hospitalization, wherein the AUC values are calculated by identifying episodes of dispensed antimicrobials; assigning one to the AUC value for the hospitalization, wherein the first episode of dispensed antimicrobials occurred on a hospital day after a first period after hospitalization begins and at least one additional antibiotic episode occurred on each of the next date of a second period or the day of discharge or the day of death; and determining the number of nosocomial infection markers (NIMs) for each patient hospitalization by one of setting the NIM equal to the AUC value if the calculated SNDHI is equal to zero, otherwise setting the NIM to the calculated number of SNDHIs. receiving from a database patient hospitalization data associated with at least one patient, wherein the patient hospitalization data is formed from combinations of patient admit, discharge and transfer data; microbiology and microbiology related test data; and antimicrobial dispensing data; calculating at a computer (101, 101a, 101b) from the patient hospitalization data a number of specimens with non-duplicate hospital isolates (SNDHI) markers for each patient hospitalization wherein, the number of SNDHI is calculated by: eliminating duplicate isolates; eliminating isolates associated with specimen contamination, surveillance, and non-infected clinical states; identifying hospital isolates, comprising identifying isolates obtained from specimens collected from a patient who has been a hospitalized patient one or more times within a period of days or hours prior to specimen collection and/or after the patient has been in the hospital for a period of time; and calculating the sum of SNDHIs; eliminating duplicate isolates; eliminating isolates associated with specimen contamination, surveillance, and non-infected clinical states; identifying hospital isolates, comprising identifying isolates obtained from specimens collected from a patient who has been a hospitalized patient one or more times within a period of days or hours prior to specimen collection and/or after the patient has been in the hospital for a period of time; and calculating the sum of SNDHIs; calculating from the patient hospitalization data, antibiotic utilization criteria values for each patient hospitalization, wherein the AUC values are calculated by identifying episodes of dispensed antimicrobials; assigning one to the AUC value for the hospitalization, wherein the first episode of dispensed antimicrobials occurred on a hospital day after a first period after hospitalization begins and at least one additional antibiotic episode occurred on each of the next date of a second period or the day of discharge or the day of death; and identifying episodes of dispensed antimicrobials; assigning one to the AUC value for the hospitalization, wherein the first episode of dispensed antimicrobials occurred on a hospital day after a first period after hospitalization begins and at least one additional antibiotic episode occurred on each of the next date of a second period or the day of discharge or the day of death; and determining the number of nosocomial infection markers (NIMs) for each patient hospitalization by one of setting the NIM equal to the AUC value if the calculated SNDHI is equal to zero, otherwise setting the NIM to the calculated number of SNDHIs.