Hospital Ice Machines Linked to 46 Burkholderia Infections in California and Colorado

Ice machines have mechanical parts where microbes can multiply and form biofilms, and using ice or tap water in patient care is a known route for water-related germs to cause hospital infections. Burkholderia multivorans belongs to the Burkholderia cepacia complex, water-related bacteria common in soil and water that can resist antibiotics and cause severe infections, especially in people who are immunocompromised or critically ill. It's often found in the sputum of people with cystic fibrosis but rarely otherwise.

How the outbreak unfolded

In August 2021–July 2022, two hospitals in a southern California health system reported B. multivorans infections in 23 patients without cystic fibrosis. Staff there often used ice and water from ice machines in care — bed baths, swallowing evaluations, ice packs for pain — and the same strain, sequence type ST659, turned up in ice and water from one hospital's machines. That type had never before been found in the United States. Reports from other hospitals led CDC and state and local health departments to look further.

That's the original 23 plus 23 previously unreported cases.

The patients

• Median age 60 (range 21–97); 61% male.
• 76% were in a medical intensive care unit when the specimen was taken.
• The first positive culture was most often respiratory (70%), then blood (17%). At Hospital D, half came from abdominal specimens.
• 21 (46%) had died, according to medical records; the timing and cause of death weren't determined.
• Three cases came months after others at the same hospital; those patients may have been infected during an earlier stay.

What investigators found

• Common equipment: all four hospitals used the same brand of ice machine and the same brands of filters, descaling and sanitizing products, and patients at all four may have drunk or been exposed to machine ice and water — for swallowing tests, pain relief, cooling and bathing.
• In the machines: B. multivorans was found in ice, water and a drain pan from two ICU machines at Hospital B (March and July 2022) and in six of 10 machines at Hospital D (July 2023–March 2024). Hospital A's machine had tested negative in March 2021 and was later replaced. At Hospital C none was found, but one machine's water had 102,000 colony-forming units per mL of bacteria, above the EPA's recommended level for drinking water.
• Elsewhere: sinks, common products such as chlorhexidine mouthwash, ultrasound gel and bathing cloths, and the descaling and sanitizing products all tested negative.
• Genetics: whole genome sequencing of isolates from all 46 patients and four machine samples showed they were all ST659 and highly similar — 0–14 single-nucleotide differences across 81% of the reference genome.

Cases by month of first positive culture and hospital, with ice machine removals and health department visits marked. From CDC's MMWR.

Because the same strain appeared in the same brand of machine at hospitals in two states, investigators raised the possibility of a contaminated machine component or related product. Hospital D's high share of abdominal infections fits its practice of putting refillable ice bags directly on abdominal surgical wounds and device insertion sites. An investigation into the source continues.

Response

• Health officials told each hospital to avoid tap water and machine ice in clinical care, especially for vulnerable patients: Hospital A in December 2020–February 2021, Hospitals B and C in March–August 2022, and Hospital D in July 2023.
• Every ice machine found to carry the bacteria was taken out of service.
• In March 2024, CDC sent a national alert to find more cases.

Limits: the product samples tested may not have come from the same lots used when patients were exposed, and medical records don't document exposure to ice or tap water.

Recommendations

• Health care facilities should run a water management program that identifies every path by which water could reach patients.
• During outbreaks of water-related organisms, consider avoiding tap water, including machine ice and water, for patient care.
• Report health care–associated B. multivorans outbreaks to public health officials.

Sources

Based on Vazquez Deida AA, Spicer KB, McNamara KX, et al., "Burkholderia multivorans Infections Associated with Use of Ice and Water from Ice Machines for Patient Care Activities — Four Hospitals, California and Colorado, 2020–2024," Morbidity and Mortality Weekly Report 73(39), CDC; a work of the United States government in the public domain.