Yes, septic bursitis can spread. 

More Info: When bursitis becomes infected by bacteria, a condition known as septic bursitis, the infection can travel via the bloodstream to different areas of the body leading to a potentially life-threatening situation. In contrast, however, non-infected bursitis remains localized and, although it can cause stiffness and swelling, does not pose a life-threatening risk.

What Is Bursitis?

Bursae are fluid-filled sacs whose purpose is to cushion and reduce the pressure imposed on the joints of the body. In the case of bursitis, your bursae become inflamed meaning that they swell with fluid leading to an increased pressure on the joints. The typical side effects of bursitis are a feeling of pressure and pain in the affected joint. The most common areas of the body where bursitis is experienced are the shoulder, ankle, toe, elbow, and hip. Bursitis is often treated with a cortisone injection in order to reduce swelling. Frequent use of ice and rest of the aggravated joint in order to avoid increased swelling is also recommended.

Septic Bursitis vs. Aseptic Bursitis

Although it is sometimes difficult to distinguish septic bursitis from aseptic (non-infectious) bursitis, it is crucial to make the distinction as early in the infection as possible in order to start appropriate treatment. To diagnose, the fluid within the bursae can be examined for microbes in order to determine whether bacteria have infected the area. Septic bursitis can range from mild to severe with oral antibiotic therapy being the most common course of treatment. However, depending on the severity, intravenous therapy and occasionally surgery are found necessary.