The Centers for Disease Control and Prevention is investigating cases of blood infections suspected to have been caused by medical syringes contaminated with bacteria.

The infection has caused illnesses to about 40 people in Texas and Illinois, including 20 outpatients at Rush University Medical Center in Chicago. No deaths have been reported.

Fourteen people from the 20 Rush outpatients needed hospitalization, but they all responded very well to the administered treatment. The last one left the hospital Tuesday, said Dr. John Segreti, hospital epidemiologist according to the Associated Press.

The infections can cause fever and chills. The good news is that they seem to respond well to antibiotics.

Doctors at Rush discovered the infections to heparin-filled syringes used by the patients undergoing home treatment. The syringes seemed to have been pre-filled with heparin, a substance that thins the blood consistency. The bacteria, called Serratia marcescens, was found in a batch of the syringes produced and delivered by a company called Sierra Pre-Filled in Angier, N.C.

According to Dr. Arjun Srinivasan of the federal Centers for Disease Control, syringes from the contaminated batch were sent off to Colorado, Florida and Pennsylvania as well.

As a response to the investigation, Dushyant Patel, president of Sierra Pre-Filled, said that the company already had recalled the contaminated batch, which has the number 070926H. The company, together with the CDC, is currently working to ensure doctors are aware about the contamination and that more cases could surface.

"There's nothing out there anymore. Our highest priority is to ensure that all of those cases that occur are identified," said Patel.

“We'll be working to perform genetic fingerprinting on the bacteria to confirm a link between bacteria in the syringes and the case patients," Dr. Srinivasan said, according to the AP. He also advises patients who believe they used infected syringes to contact their doctors immediately.