By Dr Ananya Mandal, MD

      The U.S. Food and Drug Administration (FDA) has issued warnings for doctors, hospitals and clinics regarding contaminated ultrasound gel produced by a New Jersey company that infected 16 cardiac patients and could pose serious risks to pregnant women and others who undergo ultrasound imaging and treatment.

      The news release from the FDA says that the gel – used by radiologists, urologists, gastroenterologists, OB-GYNs, internists, nurses and ultrasound technicians for diagnostic ultrasound testing – is contaminated with two strains of bacteria. Chiropractors and physical therapists also use the gel for therapeutic ultrasound treatment of pain, inflammation and injuries. “Although Other-Sonic Generic Ultrasound Transmission Gel is not labelled as either sterile or non-sterile, it is NOT sterile,” the FDA cautioned.

      The FDA said that 16 heart patients became infected with the bacteria, Pseudomonas aeruginosa, while undergoing transesophageal ultrasound exams with Other-Sonic Generic Ultrasound Transmission Gel during heart valve replacement surgery at a single hospital. The product is made by Pharmaceutical Innovations Inc., of Newark, N.J., which bills itself on its website as “world leader in medical ultrasound.”

      The FDA also declined to identify the Michigan hospital when it released information about the seizure on Wednesday. But the hospital was identified as the Beaumont Health System in Royal Oak, in an April report published by the Centers of Disease Control and Prevention on the infections.

      In February the FDA had analyzed product samples and found “significant amounts of Pseudomonas aeruginosa and Klebsiella oxytoca”, which the FDA said suggested that the contamination occurred “during the manufacturing process.”  Both types of bacteria can colonize the skin without causing any symptoms, although Pseudomonas also may cause skin eruptions, even on unbroken skin, the FDA warned. More concerning, however, is the potential of the bacteria to enter the body through ultrasound exams of the airway, lower digestive tract or a woman’s genital tract, where they could cause infection.

      “Intact skin is a fairly good barrier to infection,” said Dr. Robert A. Winters, an infectious disease specialist in Santa Monica, Calif. He said that fetal ultrasounds and ultrasounds of organs like the gall bladder, where the gel is applied to overlying skin, are of “lower concern” than more invasive ultrasounds where a probe is inserted into the body, such as during transesophageal imaging. “On the other hand, they’re using the probe, they’re moving it on the skin, they could be abrading the skin and potentially introducing germs into otherwise clean sites. There is probably some small added risk if you’re undergoing ultrasound with a contaminated gel product.”

      But he added, “We all are interacting with lots of different bacteria all day long.” If you’re concerned about possible exposure to a contaminated gel, “the best thing to do is go home and take a good shower with soap and water,” or make sure the people performing your ultrasound “pat the area with alcohol afterwards,” said Winters, chairman of the infection control division at Saint John’s Health Center in Santa Monica.