Classically, Escherichia coli was the agent of 50% of Gram-negative bacteremia, but in the 1960s there was an increasing incidence of Klebsiella-Aerobacter infections, besides of the Pseudomonas aeruginosa and Proteus group, due to their antimicrobial resistance.1 Gonçalves AJR et al. (1968) reviewed 31 cases of Gram-negative infections managed in a Brazilian general hospital of Rio de Janeiro, and the most common organisms were E. coli and Klebsiella-Aerobacter (58% of the cases) followed by the Pseudomonas group.1 Males were more affected, and in 61.3% of cases the urinary tract was the original site of infection, and previous treatment occurred in several patients who underwent antibiotics, corticosteroids, or cytostatic drugs; and the most frequent predisposing conditions were diabetes mellitus and malignancies. The urinary tract manipulation (with or without previous infection), gastrointestinal surgery, and urinary or biliary tract obstructions were the main precipitant factors. Chills, fever and arterial hypotension were the most frequent clinical manifestations; circulatory shock occurred in 58% of cases, which was considered a very high incidence in comparison with previous literature data.1 The development of bacteremia was more frequent (29%) among the patients between 51 and 60 years of age, but the higher mortality rate (66.7%) occurred in the 41 to 50 age group.1 The mortality rate due to isolated bacteremia was 30.7%, while the associated circulatory shock raised it to 72.2%, and Pseudomonas infections evolved with 100% of mortality.1 The antibiotics utilized at that time were ampicillin (AMP), chloramphenicol (CHL), cephalosporin (CEP), colistin (COL), penicillin G (PenG), gentamicin (GEN), kanamycin (KAN), streptomycin (STR), and tetracycline (TC). The schedules (before hemocultures and antibiograms) were: 1) STR (1-2 g/day) plus TC (1.5-2 g/day), or CHL (2 g/day); 2) KAN (1.5-2 g/day) plus TC, or CHL; 3) in suspicion of Pseudomonas: COL (1 million units 8/8 hs, or 12/12 hs) plus TC, or CHL; 4) PenG (20-80 million units /day), isolated or associated with STR, CEP, or KAN; 5) AMP (4 g/day), isolated or associated with KAN; 6) CEP (2-4 g /day or 6-8 g /day) isolated or associated with PenG or KAN; and 7) GEN (120 mg/day) for the cases of Pseudomonas, E. coli, or Klebsiella-Aerobacter infections.1 The authors emphasized the prognosis depending on the underlying disease, the presence or absence of shock, the prompt diagnosis and the immediate and effective treatment.1
