Virulent Staphylococcal Infections.

NZMJ, 1924.

A CLINICAL AND PATHOLOGICAL STUDY OF TWENTY CASES.

By P. P. Lynch, M.D., Ch.B., B.Sc. (from the Departments of Bacteriology and Pathology, Otago University), being an abstract from a thesis submitted for the degree of M.D.

Preliminary Discussion.—At intervals during the past two or three years my attention has been drawn to the frequency with which the staphylococcus has been encountered in the cases which have come under my notice, for the most part at the Dunedin Hospital. Some of these were studied first from the bacteriological side, but many were seen for the first time at post mortem. One has been accustomed to look upon this organism as being commonly enough met with in mild superficial infections, but only rarely in grave visceral lesions and in fatal cases. A study of the clinical and pathological records of previous years has served to confirm this view.

In searching for the causes underlying this comparatively sudden appearance of severe staphylococcal infections, the first fact to be noticed (and it has been remarked on more than once), was that in the influenza epidemic of 1918–19 a variety of organisms was encountered as secondary invaders in the lung lesions, and very frequently the nature of the invader determined the type of lesion found, and likewise in a large measure influenced the prognosis. It was remarked at the time by several independent observers that in quite a number of cases an unusual feature was the occurrence of a staphylococcus aureus as the chief or sole secondary invading organisms. On studying the literature of that epidemic one finds that this observation was made by observers in many different countries.

The type of lesion associated with this organism is sufficiently definite and characteristic to be easily recognised, and on going through the case records and post mortem reports of the epidemic in Dunedin, we find several cases in which the staphylococcus was found as the principal organism. A study of the pathology of these cases, both macroscopically and microscopically, is contained in the case reports which follow in the second part of this paper. Although they may appear to have little direct bearing on the subject, nevertheless these cases are mentioned because I consider they help us to a fuller understanding of the pathogenicity of the staphylococcus as studied in the later cases. Within a short time after the subsidence of the epidemic we find cases occurring in which the staphylococcus is the infecting agent, and which are of such grave severity and rapidly fatal course as at once to attract our attention. It is interesting to note that a similiar observation was made by Chickering and Park in New York in the early months of 1919 (11). They record a series of cases in which rapidly fatal pulmonary conditions were found post mortem, associated with acute hæmorrhagic areas with multiple abscess formation. From these abscesses a pure culture of staphylococcus aureus could in all cases be obtained. The lesions present in these cases were most unusual, but nevertheless correspond in site and nature with those found in Case III. quoted below. Furthermore, when Minowski (21) published his study of the empyemata arising from the pneumonias of 1918–19, it was noticed that in a considerable percentage of the cases the staphylococcus aureus was found as the responsible organism. In those cases which came to post mortem the pathology of the lung condition was quite different from that encountered in the frank pneumonias commonly met with in ordinary practice. There was almost always present a sub-pleural abscess. This is all the more remarkable because in the cases to follow the presence of sub-pleural abscesses was noted frequently enough in all stages of formation, and some had recently ruptured into the pleural cavity. These would in time have ultimately given rise to staphylococcal empyemata, had the cases survived. I record this observation because I think it has a considerable bearing on the pathology of empyema in epidemic pneumonias. We observed the phenomenon in 1918 and again in 1923 (15).

In February, 1922, an opportunity arose of studying, both clinically and pathologically, a case of staphylococcus aureus endocarditis in a young man of 23. The rapid onset and tragically sudden exitus were very startling. The occurrence of a second case of the same nature and with almost exactly similar lesions, which I had an opportunity of examining post mortem, served to confirm this impression and I had yet to see a third case of the same kind, during the short period over which this study extends.