Investigating an Elizabethkingia anophelis Cluster in a Pediatric ICU

Intensive care units (ICUs) are the last place infection preventionists want to see an outbreak. There is no “good” location for an outbreak, but an ICU is perhaps one of the worst, as the sickest, most vulnerable patients are cared for in such units. Like an oncology unit, an ICU experiencing cases of infection with an unusual organism can represent a canary in the coal mine.

Elizabethkingia bacteria are found in soil, river water, and reservoirs; however, they tend to only cause disease for those with weakened immune systems. The most common manifestations are meningitis and respiratory infections.

Within the United States, the US Centers for Disease Control and Prevention (CDC) reports roughly 5 to 10 cases per state, per year. Although, these gram-negative bacteria can be resistant to common antibiotics, infections can be treated with alternate antibiotics. As such, the CDC encourages health care laboratories to confirm the presence of E anophelis through MALDI-TOF and optical mapping to ensure antibiotic susceptibility is performed in order to ensure the infected patient receives the right treatment.

Late May 2017, 3 patients in the pediatric ICU at KK Women’s and Children’s Hospital in Singapore were found to be infected with E anophelis. Even more concerning, these patients were found to have the infection within 13 days of each other and all 3 cases were isolated from blind bronchial sampling via endotracheal tubes.

Epidemiological investigation into the patients and environmental testing was performed to try and establish a source for the infections. Given that E anophelis has a proclivity for water sources, the first place for environmental testing was all tap outlets within the clinical areas, which included swabbing the aerators and collecting water samples. It is important to note that the hospital water sources did not have supplemental treatments but did meet World Health Organization guidelines for drinking-water quality.

Further testing included the hands of nurses working in the unit. The investigators had volunteer nurses place their hands onto agar plates during 3 particular phases: before handwashing, after handwashing with chlorhexidine soap and tap water from the outlet known to be positive for E anophelis, and finally, after they used alcohol-based hand sanitizer.

Of the 27 environmental samples collected (from 9 tap outlets or sinks), 10 were positive for E anophelis, including samples from the rooms of the infected patients. One sample was positive for E meningoseptica. Only 1 of the 16 rooms tested negative for any Elizabethkingia bacteria.

The testing of nurses’ hands found that of the 2 tested, only 1 acquired E anophelis on her hands following handwashing but that it was no longer detectable after she had used an alcohol-based hand sanitizer.

Following the identification of the source for this cluster, the hospital reinforced infection control practices through standard precautions, hand hygiene, and more stringent environmental disinfecting practices. All aerators were removed from the tap outlets in the ICU, which was found to successfully eradicate the bacteria through additional water testing. Hospital staff also reminded staff not to dispose of patient body fluids in the sinks used for handwashing, and reinforced the use of hand sanitizer unless hands were visibly soiled.

E anophelis is quite rare and there have only been 2 confirmed outbreak in humans: one in an ICU in Singapore, and the other a large community outbreak in the United States. Infection control measures against the pathogen can be challenging as the source of exposure is not always identified. Although the tap outlets with aerators were found to be the source for this E anophelis cluster, a lack of mandated reporting for the infection in many states (and countries) means that outbreaks may be underreported. Finding a point source for such outbreaks is often challenging but ultimately reinforces the importance of basic infection control practices, especially in ICUs.