A prospective study of Staphylococcus aureus nasal colonization and intravenous therapy-related phlebitis

Intravenous (IV) therapy-associated phlebitis is common, but its causes are ill defined. Some cases may be related to bacterial colonization of the skin surrounding the IV catheter, especially by Staphylococcus aureus. This prospective study examined the association of phlebitis with anterior nares S aureus carriage, as well as with other potential risk factors.

Selected demographic and clinical data and a nares culture were collected from patients on designated wards by us and from the IV therapy team at the time of initial IV catheter placement. Patients were followed up for signs and symptoms of phlebitis for the duration of the initial catheter's use and for up to two additional IV placements. Potential risk factors were compared for patients who developed phlebitis and those who did not by the Cox multivariate proportional hazards model.

During 10 weeks, 273 men with a total of 416 catheter placements had fully evaluable data. Phlebitis occurred during 13.7% of the catheter placements. Nasal cultures yielded S aureus from 14.3% of the patients, but none of the IV team nurses. Surprisingly, S aureus nasal colonization was related (at borderline statistical significance) to a reduction in phlebitis risk. Location of the patient on a surgical ward, the presence of infection at any site, and a larger-gauge catheter were each significant independent risk factors for phlebitis. The highest risk of phlebitis appeared to have been within 12 to 24 hours of catheter placement.

The primary finding of this study was that nasal colonization with S aureus did not increase the risk of developing IV catheter-associated phlebitis. Our rate of IV catheter-associated phlebitis was similar to that in other studies, but the factors predisposing to phlebitis differed somewhat from those in previous studies.