We're unable to sign you in at this time. Please try again in a few minutes.
We were able to sign you in, but your subscription(s) could not be found. Please try again in a few minutes.
There may be a problem with your account. Please contact the AMA Service Center to resolve this issue.
Contact the AMA Service Center:
Telephone: 1 (800) 262-2350 or 1 (312) 670-7827  *   Email: subscriptions@jamanetwork.com
Error Message ......
From the Centers for Disease Control and Prevention | Morbidity and Mortality Weekly Report|

Pseudomonas aeruginosa Respiratory Tract Infections Associated With Contaminated Ultrasound Gel Used for Transesophageal Echocardiography—Michigan, December 2011–January 2012 FREE

JAMA. 2012;307(21):2248-2250. doi:.
Text Size: A A A
Published online

MMWR. 2012;61:262-264

1 table omitted

In late December 2011, the Department of Epidemiology at Beaumont Health System (BHS) in Royal Oak, Michigan, noted an increase in the number of positive respiratory cultures in one surgical intensive-care unit (ICU), prompting further investigation. The increase in positive cultures was attributed entirely to Pseudomonas aeruginosa. Investigation by BHS staff members found that all of these positive cultures were related to use of ultrasound transmission gel from a single manufacturer during transesophageal echocardiography. Seven patients were infected with P. aeruginosa based on National Healthcare Safety Network (NHSN) criteria,1 and nine were colonized. Cultures from one open and one unopened bottle of the gel grew P. aeruginosa closely related to the outbreak strain based on molecular typing via repetitive extragenic palindromic polymerase chain reaction (rep-PCR). The Oakland County Health Department, the Michigan Department of Community Health, and the Food and Drug Administration (FDA) were notified of the findings. On January 23, all implicated ultrasound gel in multiuse bottles was removed from BHS facilities and replaced with a single-use, sterile ultrasound gel for all potentially invasive procedures. On April 18, FDA issued a Safety Communication* advising health-care professionals and facilities not to use certain lot numbers of the ultrasound transmission gel and further advising that the only ultrasound gel that is sterile is unopened gel in containers labeled as sterile. To date, no further respiratory cultures have been positive for P. aeruginosa.

Surveillance for nosocomial infection at BHS is driven by results of clinical microbiology cultures. Positive cultures are reviewed using a combination of microbiology reports and paper or electronic medical records to determine infections and colonizations. Initial review found P. aeruginosa in respiratory specimens taken from endotracheal tubes in 10 patients in a single surgical ICU in December. No cultures of these patients' surgical sites or blood grew P. aeruginosa. The same unit had averaged less than three respiratory tract cultures positive for P. aeruginosa monthly during the preceding 11 months and had only one infection by NHSN criteria during that period.

Review of the 10 P. aeruginosa cultures revealed that all patients had undergone cardiovascular surgery. No clustering by operating room, surgeon, operating room staff member, ICU room number, or nursing staff was observed. Because all isolates were from the respiratory tract, the initial focus included a review of postoperative nursing and respiratory-care practices, respiratory therapy equipment management, and anesthesia practice and equipment management. No clustering by respiratory medications administered was observed. Discussion with operating room staff members revealed that a unique aspect of these patients' surgeries included the use of an intraoperative transesophageal echocardiogram (TEE). TEEs involve the insertion of a probe with an ultrasound conducting tip into a patient's esophagus and are used during cardiovascular surgery to aid in visualization of the posterior of the heart. The TEE probe is coated with a coupling gel and then inserted by an anesthesiologist before surgical incision. Their duration of placement depends on the specific procedure being performed. Environmental cultures of TEE probes, storage tubes, and work surfaces were performed, and all TEE probes were inspected. All cultures were negative, and only one probe had a mechanical defect; this probe was removed from use.

Intensified surveillance (performing respiratory tract cultures on all mechanically ventilated patients in this surgical ICU) during January 6-20 identified six additional patients colonized with P. aeruginosa (of the 20 patients tested). All six of these patients also had undergone cardiovascular surgery. Surveillance respiratory cultures from another surgical ICU identified only one patient colonized (of the 11 patients tested) with P. aeruginosa ; this isolate had a different antibiotic susceptibility pattern from those of the 16 isolates found earlier. Of the 16 patients identified during the outbreak, two had pneumonia, five had tracheobronchitis, and nine had respiratory tract colonization only. Time from surgery to identification of a positive culture from a respiratory tract specimen ranged from 2 to 14 days (median: 5 days). The patients had undergone various surgical procedures. Those who had undergone valvular surgery alone (n = 13) were at significantly higher risk (relative risk = 5.7, 95% confidence interval = 1.75-18.86) for Pseudomonas infection or colonization than those who had undergone coronary artery bypass grafting alone (n = 32). The investigation noted that patients undergoing valvular surgery have TEE probes in place during nearly the entire procedure, whereas those undergoing coronary artery bypass grafting had shorter durations of TEE use. A review of operative times found that procedures lasting ≥5 hours (n = 70) were more frequently associated with P. aeruginosa infection or colonization (relative risk = 6.4, 95% confidence interval = 0.89-46.45) than procedures lasting <5 hours (n = 30).

The investigation focused further on manipulations of the respiratory and gastrointestinal tract. An ultrasound transmission gel, Other-Sonic (Pharmaceutical Innovations, Inc., Newark, New Jersey), which was not labeled or sold as a sterile product, was used with TEE probes. The multidose containers of gel were collected and replaced with a single-use, sterile product on January 23. After this change, no additional respiratory cultures with P. aeruginosa were observed.

Molecular typing was performed on the 10 isolates on January 26, and all were determined to be >99% similar by rep-PCR. Cultures of the four previously opened Other-Sonic ultrasound transmission gel bottles removed from the operating room were performed; one of four samples grew P. aeruginosa, and molecular typing revealed it to be highly related (>99%) to the outbreak strain. Five other strains of P. aeruginosa isolated throughout the hospital during the outbreak period also were analyzed and determined to be unrelated to each other or the outbreak strain. Two bottles of sealed, unopened Other-Sonic ultrasound transmission gel subsequently were cultured, one of which grew P. aeruginosa. At this point a health-care system—wide recall of all bottles of Other-Sonic ultrasound transmission gel was initiated, local and state health departments were contacted, and FDA was notified. Additional molecular typing studies (using rep-PCR) showed that the Pseudomonas isolate from the sealed bottle also was >99% similar to the outbreak strain, strongly suggesting contamination of the product during manufacturing, packaging, storage, or shipping.


Paul Chittick, MD, Victoria Russo, MPH, Matthew Sims, MD, Susan Oleszkowicz, MPH, Kara Sawarynski, PhD, Kimberly Powell, Jacob Makin, Elizabeth Darnell, Barbara Robinson-Dunn, PhD, Bobby L. Boyanton Jr, MD, Jeffrey Band, MD, Beaumont Health System, Royal Oak, Michigan. Corresponding contributor: Paul Chittick, paul.chittick@beaumont.edu, 248-551-0365.


This report describes an outbreak of Pseudomonas aeruginosa respiratory tract colonization and infection related to the use of contaminated ultrasound transmission gel. Sixteen cardiovascular surgery patients were affected during the outbreak, seven with infection per NHSN criteria, and nine with colonization. Initial investigation suggested the possibility that the TEE probes were the source of the outbreak, given that contaminated TEE probes have been linked to pulmonary infection outbreaks of Legionella previously.2 However, surveillance cultures of the probes were negative, and there was no evidence that all case patients were linked to the use of a particular probe. The ultrasound transmission gel, however, was contaminated with P. aeruginosa. Although contamination during use was initially suspected, the fact that one of two tested bottles of sealed, unopened product was contaminated with P. aeruginosa suggests that the contamination might have occurred before the product reached BHS.

Contaminated ultrasound gels have been associated with outbreaks of infection in various settings and with various organisms, including Klebsiella,3Burkholderia,4,5Achromobacter,6 and Staphylococcus aureus.7 Although most of these outbreaks were believed to have occurred from inappropriate use of products, in one circumstance it was determined that the gel had been contaminated at the site of production.4 Although these gels contain parabens or methyl benzoate, which are thought to render them bacteriostatic, some Gram-negative bacteria can degrade these components,4 and investigations of several reported outbreaks suggest extrinsic contamination of gels might easily occur.3,5-7 One study demonstrated that an ultrasound gel had no intrinsic antimicrobial properties,8 and interestingly, results of another in vitro study suggested Pseudomonas spp. might actually survive for shorter periods in ultrasound gel compared with S. aureus or Escherichia coli.9 No ingredient information is available publicly for Other-Sonic ultrasound gel.

Numerous products are available to be used as ultrasound transmission gels. No national guidelines exist in the United States recommending specific types of gel for specific procedures. However, in 2004, Health Canada issued recommendations for minimizing the health risks of using gels.10 These recommendations suggested use of single-use, sterile gels for invasive procedures that pass through a tissue, for all studies involving neonates, for all procedures involving sterile equipment or non-intact skin, and for procedures on intact mucous membranes. The results of this report further support a recommendation for the use of only sterile gels for invasive procedures and procedures involving contact with nonintact skin or mucous membranes. Moreover, because only unopened ultrasound gel containers labeled as sterile should be considered sterile and extrinsic contamination might easily occur, only single-use sterile products should be used for such purposes.


Pamela Bozigar, Mary Dietrich, Julie Jordan, MHSA, Paula Keller, MS, Rhea Sautter, MBA, Beaumont Health System, Royal Oak, Michigan.

What is already known on this topic?

Medical gels have been linked to outbreaks of infection in several reports, including reports of gels contaminated at the site of packaging. As a result, Health Canada in 2004 issued recommendations for minimizing the risk for infection from medical gels. No such guidelines exist in the United States.

What is added by this report?

An outbreak of seven cases of Pseudomonas aeruginosa respiratory tract infection and nine instances of respiratory tract colonization was linked to contaminated ultrasound gel. P. aeruginosa isolates found in 10 patients, one of four opened gel bottles in use in the operating room, and one of two unopened, sealed gel bottles were found to be more than 99% similar by molecular typing.

What are the implications for public health practice?

Because of the risk that an ultrasound gel might be contaminated with P. aeruginosa or other bacteria, single-use, sterile products should be used for invasive procedures and procedures involving contact with nonintact skin or mucous membranes.


10 Available.




Also Meets CME requirements for:
Browse CME for all U.S. States
Accreditation Information
The American Medical Association is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians. The AMA designates this journal-based CME activity for a maximum of 1 AMA PRA Category 1 CreditTM per course. Physicians should claim only the credit commensurate with the extent of their participation in the activity. Physicians who complete the CME course and score at least 80% correct on the quiz are eligible for AMA PRA Category 1 CreditTM.
Note: You must get at least of the answers correct to pass this quiz.
Please click the checkbox indicating that you have read the full article in order to submit your answers.
Your answers have been saved for later.
You have not filled in all the answers to complete this quiz
The following questions were not answered:
Sorry, you have unsuccessfully completed this CME quiz with a score of
The following questions were not answered correctly:
Commitment to Change (optional):
Indicate what change(s) you will implement in your practice, if any, based on this CME course.
Your quiz results:
The filled radio buttons indicate your responses. The preferred responses are highlighted
For CME Course: A Proposed Model for Initial Assessment and Management of Acute Heart Failure Syndromes
Indicate what changes(s) you will implement in your practice, if any, based on this CME course.


Some tools below are only available to our subscribers or users with an online account.

0 Citations

Related Content

Customize your page view by dragging & repositioning the boxes below.

Articles Related By Topic
Related Collections
PubMed Articles