The value of bacteriological studies in pneumonia occurring in age group 15-60.

The purpose of this study was to evaluate the routine need for bacteriological studies as a guide to therapy and prognosis of patients with pneumonia in a selected age group. Bacteriological studies in pneumonia may be of value for diagnosis, treatment, prognosis, and epidemiology. The clinician is interested in bacteriological studies primarily because they may serve as a guide to treatment. Although the literature contains relatively little statistical evidence, it is entirely logical to expect that the type of antibiotic treatment could be determined from bacteriological studies. For this reason, the opinion is generally held that the type of antibiotic treatment should depend upon the results of appropriate bacteriological investigation. The positive correlation between results of bacteriological studies and the subsequent response to therapy is evident to everyone treating pneumonia. However, it does not necessarily follow that bacteriological studies are essential to the satisfactory treatment of all patients with pneumonia. Several factors need to be considered when investigating this subject. The chief means of bacteriological examination in pneumonia are by blood culture, throat smear and culture, and sputum smear and culture. Except for an occasional contaminant which is usually recognizable as such, a positive blood culture is a reliable indication of the cause of infection. Unfortunately the blood culture is usually sterile, and even when positive, one or more days are required before the organism can be cultured and identified. Specimens obtained from the throat always contain the normal inhabitants which are seldom pathogenic. It is not rare to find that the causative organism in a case of pneumonia is not reported on either smear or culture from the throat. On rare occasion the causative agent may not even be found in sputum specimens. It may be that a carefully collected and promptly examined sputum specimen is more desirable than the usual routine method; however, this is not a common practice. Sometimes it is impossible for the patient to produce a satisfactory sample of sputum. Since it is a frequent experience to obtain a mixture of organisms without a predominant pathogen, it is often difficult to interpret the results of cultures, and sometimes they may even be misleading. When in vitro antibiotic sensitivity tests are used as a guide to therapy, some degree of success may be expected, but exceptions are not rare. Two days are routinely required after collecting the specimen before the results of in vitro antibiotic sensitivity tests are available. Treatment of the patient can not be delayed for this length of time. Thus it is apparent that be-