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.