Opportunistic Gram-Negative Rod Pulmonary Infections

¹ Department of Preventive Medicine, University of Illinois

1. The availability of effective therapy for the treatment of pneumococcal, streptococcal, staphylococcal or Hemophilus influenzal infections has not greatly reduced the frequency of death from terminal pneumonia. A study of the pathogenesis of this condition among patients with poliomyelitis indicated that in many instances, the patients had infected areas within patches of atelectasis. Staphylococci and coliform gram-negative rods were common in these patients and vomiting appeared to be important. Opportunistic gram-negative rod infections in the lung occur mainly in patients with underlying disease and are of the bronchopneumonic variety often associated with atelectasis.

2. Comparison of roles of respiratory carrier state, non-fatal infection and fulminating infection in patients who acquire coliform organisms in the respiratory tract suggested that in patients subject to secondary bronchopneumonia, these organisms are of importance in the causation of disease when they implant in the respiratory tract. While many of these infections are terminal, this was true in only one-half of the poliomyelitis patients and apparently in those in the general hospital. Even though the problem is encountered primarily in a selected group of patients, the range of infections follows the familiar pattern of varying degrees of illness in different patients.

3. Among ambulatory patients with prior pulmonary disease on treatment regimens which should favor implantation of gram-negative rods, serious infections have been a rarity. In these patients, sputum carrier states for gram-negative coliform rods were low and although the organism did seem to be associated with a slight increase in episodes of lower respiratory disease, particularly those with fever, they appeared to be much less important than among the type of patient who frequently develops terminal pneumonia.