[The cost of hospital acquired infections].

Two complementary studies were carried out. a) A three months study on nosocomial infection frequency, with a simultaneous assessment of the nosocomial infection risk factors (infected or non infected body on entry in the department, the kind of pathology, simplified scores of seriousness) and of the length of the hospital stays to compare the average length of stay for overinfected patients and for nosocomial infection non contaminated patients, after checking those factors through adjustment, themselves responsible for a prolongation of the stays. b) An evaluation of the cost of the sole antibiotics used in the treatment of a Serratia nosocomial infection epidemic which developed in the department. The quantitative and qualitative analysis of each case was made by the prescribing doctor in order to attribute its proper costs to each case. Over a three months period, 112 patients were considered as presenting a risk of nosocomial infection, which means that they were hospitalized in the department for more than 48 hours. Twenty two nosocomial infection carriers were examined; they represented 38 cases of overinfection. The length of stay was of 10.3 days among the non carriers of nosocomial infection, and of 32.4 days among the overinfected patients, but more interesting is the figure of 13.2 days per case. Over a year, it thus amounts to 1,950 hospitalization days due to nosocomial infections, which corresponds, in a department of 24 beds, to an average of 5 beds occupied permanently. Besides, the antibiotic for the 12 Serratia nosocomial infection carriers was evaluated to a cost of F. 75,000.