R factors in hospital infection

In order to assess the clinical importance of R factors 524 "coliform" infections were studied in a general hospital. Of these, 95 were caused by Pseudomonas aeruginosa. Among the remaining 429, 43% were caused by drug-resistant enterobacteria; resistance was frequently multiple and determined by transmissible R factors. Choice of therapy was thus limited but in every case at least one antibiotic, effective in vitro, was still available.