A Look into Recent Healthcare-Associated Outbreak Research by the CDC Epidemic Intelligence Service

An estimated 722,000 healthcare-associated infections occurred in acute care hospitals in the United States in 2011, and roughly 75,000 patients who acquired them died while still in the hospital, according to the Centers for Disease Control and Prevention (CDC). Officers of the CDC’s Epidemic Intelligence Service (EIS) presented the results of their recent research on healthcare-associated infections during the Healthcare-Associated Outbreaks session of the 65th Annual Epidemic Intelligence Service (EIS) Conference in Atlanta, Georgia on May 4, 2016. A summary of the research presented at this session is included below:

William C. Edens, PhD, and his colleagues found that a consumer-grade reservoir-style humidifier contaminated with Mycobacterium chelonae likely caused an outbreak of that organism, even though guidelines from the CDC and professional standards groups state that their use is not allowed in any healthcare facility.

In 2015, the Toledo-Lucas County Health Department (TLCHD) was notified of 2 patients who experienced eye pain following a LASIK procedure at a clinic and both patients were diagnosed with Mycobacterium chelonae infection. After 2 more infections, the clinic stopped all LASIK procedures.

TLCHD staff reviewed the clinic’s LASIK procedures and tested clinical samples from infected patients and environmental samples.

Four (17%) of 24 patients who had recent LASIK surgery developed M. chelonae eye infections. M. chelonae was isolated from the reservoir of the one misting humidifier, and isolates from the patients were indistinguishable or closely-related on pulsed-field gel electrophoresis. The clinic removed the humidifiers and switched to controlling air humidity through central air-conditioning.

This outbreak highlights the need for greater awareness and attention to water-containing devices as a source of nontuberculous mycobacterium (NTM) infections.

Amber M. Vasquez, MD, and colleagues found that negative-pressure isolation may concentrate dust and mold spores and increase possibly fatal mucormycosis infection risk in immunocompromised patients.

In 2015, the Pennsylvania Department of Health reported a mucormycosis cluster among solid-organ transplant recipients at an acute care hospital. The researchers reviewed microbiology and histopathology records and charts, interviewed staff, assessed the environment and conducted cohort and nested case-control studies.

They identified 1 suspect case and 3 probable cases caused by three Mucorales species. The 3 probable case-patients had had heart or lung transplants with long stays in the cardiothoracic intensive care unit’s (CTICU’s) only negative-pressure room. Of the 124 heart or lung recipients cared for in the hospital, 3 (43%) of 7 patients exposed to this negative pressure room developed mucormycosis, compared with none of those unexposed (P<.001). A nested case-control study of CTICU patients showed that only exposure to the negative-pressure room was associated with mucormycosis (odds ratio 51.3; 95% confidence interval, 5.9 to infinity).

As a result, the authors advised healthcare facilities to avoid housing immunosuppressed solid-organ transplant recipients in negative-pressure rooms unless necessary.

Jason Lake, MD, and co-authors evaluated infection control practices after hepatitis C virus (HCV) transmission in outpatient dialysis centers in New Jersey in 2015, and they found infection control lapses in all centers and dialysis-related HCV transmission in most cases. They suggested better collaboration between public health departments and hemodialysis facilities to control transmission.

They found that half of healthcare-related HCV outbreaks occurred in hemodialysis centers. From 2013 through 2015, 16 new HCV infections in 9 hemodialysis centers were reported to the New Jersey Department of Health.

Infected patients were genetically tested to identify potential source-patients. The authors assessed their HCV risk factors, observed infection control practices, calculated percent adherence to CDC-recommended practices and compared adherence among centers that reported cases early vs. late.

Infection with highly-related virus indicated a dialysis source-patient for 9 of 16 (56%) case-patients in 4 centers, and dialysis was the only risk factor for 3 of the 7 remaining case-patients in 3 centers. Adherence to best practices was seen in 25 (38%) of 66 catheter handling procedures, 97 (39%) of 248 dialysis station disinfection procedures, 58 (59%) of 98 medication injections and 72 (75%) of 96 injectable medication preparation procedures. Proper station disinfection was more common in centers reporting cases in 2013 and 2014 than in 2015 (54% vs 33%, p=0.002).

Srinivas A. Nanduri, MD, and his co-authors studied prolonged outbreak of invasive group A streptococcus (GAS) among nursing home residents in Illinois in 2015 and concluded that continued GAS transmission likely resulted from poor infection control, employees and resident colonization, and inadequate surveillance for GAS infections among employees.

GAS infection in the elderly can be fatal, and in February 2015, the Illinois Department of Public Health (IDPH) identified a cluster of GAS infections at a nursing home. After mass antibiotic prophylaxis, infections reemerged in late June, and in November, IDPH requested the CDC’s assistance.

The authors surveyed employees, observed infection control practices and conducted a case-control study comparing resident cases to time-matched resident controls. They collected throat and wound cultures from residents receiving wound care and throat cultures from employees linked to cases, and they emm typed available GAS isolates.

Multiple lapses in hand hygiene and wound care practices were found, and during 2015, 57 cases and 4 deaths occurred, 10 in residents and 7 in employees, since mass prophylaxis. All 8 case-patients in the case-control study received wound care vs 8 of 24 (33%) controls (P<0.001); 1 employee and 4 residents were colonized with GAS; and 27 of 28 (96%) of typed isolates were emm89.

The researchers advised strong infection control practices and active surveillance for new infections to prevent and control outbreaks.

Findings by Meghan Lyman, MD, and her colleagues are the first in the United States to suggest that nontuberculous mycobacteria (NTM) aerosolization by heater-cooler units (HCUs) used in cardiopulmonary bypass may infect patients, Dr. Lyman said in her talk, adding that the CDC continues to issue public health guidance and work with the FDA to improve device design.

Nontuberculous mycobacteria (NTM) cause healthcare-associated infections often related to water sources. In July 2015, Pennsylvania Department of Health notified the CDC of a cluster of NTM infections in cardiothoracic surgery (CTS) patients at one hospital.

The authors identified risk factors and exposures associated with NTM infection, evaluated infection control practices and analyzed clinical and environmental samples. They found 10 cases and 48 controls.

Among patients on CPB, exposure to bypass over 2 hours was associated with higher odds of NTM infection (odds ratio 16.5; 95% confidence interval, 3.2 to 84), and all 3 available case-patient isolates were positive for Mycobacterium chimaera with indistinguishable pulsed-field gel electrophoresis patterns. The facility had removed HCUs from service prior to onsite investigation, but environmental cultures, including water and air samples were also positive for M. chimaera. The researchers advised that the hospital enhance its TM surveillance and notify roughly 1,300 potentially exposed patients.

Lorraine L. Janeczko, MPH, is a medical science writer who creates news, continuing medical education and feature content in a wide range of specialties for clinicians, researchers and other readers. She has completed a Master of Public Health degree through the Department of Epidemiology of the Johns Hopkins Bloomberg School of Public Health and a Dana Postdoctoral Fellowship in Preventive Public Health Ophthalmology from the Wilmer Eye Institute, the Johns Hopkins University School of Medicine and the Bloomberg School.

SOURCE: EIS 2016 Conference Program, pp 92-94: Concurrent Session K2: Healthcare-Associated Outbreaks

Studies Presented:

William C. Edens, PhD, EIS officer, National Center for Emerging and Zoonotic Infectious Diseases, Mycobacterium chelonae Eye Infections Associated with Humidifier Use in an Outpatient

Laser-Assisted in situ Keratomileusis (LASIK) Clinic — Ohio, 2015

Amber M. Vasquez, MD, EIS officer, National Center for Emerging and Zoonotic Infectious Diseases, Mucormycosis Among Solid Organ Transplant Recipients at an Acute Care Hospital — Pennsylvania, 2014—2015

Jason Lake, MD, EIS officer, National Center for Emerging and Zoonotic Infectious Diseases, Assessing Infection Control Practices Following Hepatitis C Virus Transmission in Outpatient Dialysis Centers — New Jersey, 2015

Srinivas A. Nanduri, MD, EIS officer, National Center for Immunization and Respiratory Diseases , Prolonged Outbreak of Invasive Group A Streptococcus Among Nursing Home Residents — Illinois, 2015

Meghan Lyman, MD, EIS officer, National Center for Emerging and Zoonotic Infectious Diseases,

Invasive Nontuberculous Mycobacteria Infections among Cardiothoracic Surgery Patients — Hospital A, Pennsylvania, 2010—2015