[Urinary infections: observations on the frequency of microbial isolation at the hospital environment and its...

Numerous studies have been carried out to specify bacterial frequencies in the urinary tract infections. In such researches the prevalence of Gram negative bacterial species has generally emerged, the most part of these ones would be Enterobatteriaceae (and among them E. coli has a special prominent position); on the other hand several Authors have often found, among other bacterial groups (Gram positive bacteria, Pseudomonas etc.) involved in such pathologies, some differences (also remarkable) in relation to various factors, among them, the hospitalizing condition, the clinical situation, the type of infection etc. In this research we have carried out a statistical analysis of the bacterial frequencies relative to 321 positive urine cultures, trying to point out their differences in relation to hospitalized or ambulatorial patients and to single are mixed infections; above all with regard to three bacterial groups: Enterobatteriaceae, Pseudomonas species and Gram positive bacteria. The most evident result has been the absolute prevalence of Enterobacteriaceae, among them the E. coli has represented, almost always, the most frequent isolated species, followed by Proteus mirabilis, in every kind of patient (hospitalized or ambulatorial) and infection, single or double (we didn't notice, in this research, infections supported by more than two species). Moreover, we noticed, but with less clearness, especially in relation to the numerical dimension of the observations and to the short comparison of the two kind of patients, some indications pointing out that hospitalized patients (in comparison with the ambulatorial) were charged with a major frequency of the two kind of patients, some indications pointing out that hospitalized patients (in comparison with the ambulatorial) were charged with a major frequency of infections supported by Gram + bacteria and Proteus mirabilis, while the Pseudomonas species presented an opposite behaviour (contrary to what several Authors generally report in literature: but a pollution problem of the specimen might have had some influence); and as regard the single infections we observed, among them, a greater frequency of the E. coli and Gram + bacteria than among the double infections, while the Pseudomonas species happened the contrary.