Carriage of Staphylococcus aureus and Inflamed Infusion Sites With Insulin-Pump Therapy

Abstract

The most common complication of continuous subcutaneous insulin infusion (CSII) is inflammation at the infusion site. To determine possible risk factors to these infections, we studied several factors in the management of CSII and compared the pyogenic skin inflammation rate, the carriage rate of Staphylococcus aureus, and the HbA, level among 50 CSII-treated diabetic patients, 50 diabetic patients on insulin injections, 48 diabetic patients on oral medication, and 40 healthy volunteers. There was no increased carriage rate of S. aureus among CSII-treated patients (42%) as compared with the other groups. An unexpected inverse relationship existed between HbA, level and carriage rate in the CSII-treated group (HbA, 5–8%, n = 16, 69%; HbA, 8–10% n = 15, 40%; HbA, >10, n = 19, 21% P = .02). Pyogenic skin inflammations were reported by 24 (48%) CSII-treated patients, of which 18 had infected infusion sites, 6 (12%) insulin injecting patients, 2 (4%) patients on oral medication, and 3 (8%) healthy volunteers (P < .01). The occurrence of inflamed infusion sites was not associated with carriage of S. aureus, the indwelling time of the needle, or the insulin dosage per day. There was an association, however, with the type of insulin preparation classified according to the added preservative: m-cresolcontaining insulin (n = 24, 54%); methyl phydroxybenzoate- containing insulin (n = 26, 19%, P = .02). We concluded that the carriage of S. aureus is not increased among diabetic patients on CSII treatment and is not a risk factor in the occurrence of inflammation at the infusion site. The type of preservative in the insulin preparation seems to be of importance in the development of these local inflammations.