The Nature of the Lowered Resistance to Infection in Diabetes Mellitus.

That patients with diabetes have less resistance to infection than do normal individuals is a fact met with in the every-day experience of the clinician. Particularly common in diabetics are staphylococcic and streptococcic infections of the skin, B. coli infections of the urinary tract, and tubercular infections of the lungs. To be sure, since the introduction of insulin in 1922 and of protamine insulin in 1935, treatment has been so improved that excellent control of the diabetic condition is possible with almost all patients and the resistance to infection in well-controlled cases appears to approximate the normal. However, prior to 1922 and today in patients whose diabetes is poorly controlled, the lessened ability to cope with infections cannot be denied. In the infections of the feet of elderly diabetics the factor of diminished blood supply resulting from arteriosclerosis is no doubt largely responsible for the slowly healing, non-healing, or gradually extending nature of such lesions. However, allowing for this factor of poor circulation, the nature of the lowered resistance to infection still remains to a large extent unexplained. It is the purpose of this paper to present data bearing upon this point. Various factors suggest themselves as the cause of the lowered resistance to infection in the diabetic. These may be summarized as follows: