Infection poses constant risk to allograft transplant patients
ICPs can provide education, surveillance to protect and detect
[Editor’s note: In December, Hospital Infection Control presented a special report discussing the infectious disease concerns and the emerging role of infection control in xenotransplantation (animal-to-human transplants). We conclude our report with an update on infection control issues in allografts (human-to-human transplants), which are receiving renewed attention because of the scientific debate on the risks and rewards of xenotransplants.]
Allograft transplant patients recipients of human organs or tissue face formidable infection risks that threaten to immediately undermine what is often a life-saving procedure. Though improved pre-transplant screening for pathogens and more powerful immunosuppressive drugs make the success of such procedures increasingly more likely, clinicians concede the threat of infection to such vulnerable patients is a grim given.
"In the allotransplantation setting, infectious diseases are part of the everyday life of being an organ recipient," says Robert Michler, MD, associate professor of surgery and director of the cardiac transplantation service and the cardiac transplantation research laboratory at Columbia University in New York City. "Our transplant patients are more susceptible to these infections. By no means can we avoid them entirely, and I doubt we ever will."
Indeed, such immune-suppressed patients face a wide spectrum of infection risk that includes the rare but real possibility that the donor organ may harbor undetected pathogens such as HIV, cytomegalovirus, Epstein-Barr Virus, hepatitis B and C viruses (HBV and HCV), and Toxoplasma gondii.1,2 (See related story, p. 5.) Beyond the concern of direct transmission from the donor, contamination may occur during processing and handling of the organ or tissue, infection control breaches may occur during the surgical implantation, or nosocomial pathogens may be transmitted in the hospital where the patient may undergo a prolonged stay.
In addition to whole-organ allografts, there are emerging infection control concerns with human tissue grafts, as reflected by the expected finalization this year of new testing and tracking regulations by the Food and Drug Administration. (See related story, p. 6.) In that regard, the Centers for Disease Control and Prevention recently reported an unusual cluster of nosocomial meningitis cases in three pediatric patients receiving pericardial tissue grafts through a collaborative procedure by the University of Utah School of Medicine and the Primary Children’s Medical Center in Salt Lake City. The outbreak was linked to a contaminated saline processing solution and inadequate testing of the tissues before implantation.3,4 (See related story in Hospital Infection Control, October 1996, p. 134.)
Feds emphasize infection control
In reporting the case, the CDC concluded more stringent attention to infection control including compliance with existing protocols and development of new guidelines may be needed for tissue transplants. The recent Public Health Service guidelines on xenotransplantation also emphasized a heightened presence for infection control, including designating key roles for hospital epidemiology from the outset.5 The debate surrounding those guidelines refocused attention on solid-organ allograft procedures, raising questions of whether infection control professionals should be more involved in those programs as well.
"This whole area of xenotransplants, as well as human transplantation, is just exploding and is probably going to continue doing that into the future," says William Jarvis, MD, acting director of the CDC hospital infections program. "How involved infection control is in this area varies tremendously from one institution to another. There clearly is a role here for close cooperation and collaboration between infection control and the transplant [clinicians]."
For example, ICPs experienced in dealing with immune-compromised patients can address such infection control issues in transplant patients as antimicrobial resistance, use of prophylactic agents, vaccination of patients, isolation measures, and precautions with visitors, Jarvis says. In addition, ICPs have taken active roles in preventing aspergillosis infections in bone marrow recipients and other transplant patients by adopting rigorous protocols to control construction dust and related contamination during hospital renovation projects. (See related story in Hospital Infection Control, October 1995, pp. 125-131.)
While ensuring such programs are in place, ICPs at transplant centers may also educate patients about their infection risks before and after the procedures. Transplant patients at St. Luke’s Episcopal Hospital in Houston which performs whole-organ transplants including heart, kidney, and liver attend a series of educational presentations that include a common-sense session on infection control, says Virginia Kennedy, RN, MS, CIC, an infection control professional at the facility.
Patient education plays a role
In addition to addressing the pre-transplant screening of the donor organs, the patients are reminded they must have all their appropriate immunizations; practice frequent handwashing; and avoid exposures to sick friends and relatives to decrease any risk they may have of acquiring a cold or other minor infection prior to the procedure, she notes. In the post-transplant period, when patients may be on powerful immunosuppressive drugs to prevent organ rejection, they are advised to take common-sense precautions like wearing gloves when gardening to avoid getting cuts and scrapes on their hands, she says.
"We answer lots of questions for the families on everything from the kitty litter box to pet iguanas," she says. "We make sure that they generally have a thought process of being aware of what they are doing and what they can do to minimize risk to themselves."
In general, ICPs can make their greatest impact in the protection of transplant patients from nosocomial pathogens like drug-resistant bacteria through surveillance and control efforts in the immediate post-transplant period, says Marian Michaels, MD, MPH, transplant infectious disease physician at the Childrens Hospital of Pittsburgh.
"Early after transplant, when they are most heavily immunosuppressed and they are in the hospital with central lines in place that’s when the nosocomial infections are occurring," she says. "I suspect [ICPs] are not used to the best advantage that they could be used. They have a strong role that could be played during that time period."
Overall, post-transplant infections in allograft recipients both donor-transmitted and nosocomial tend to appear on a predictable time line over a roughly 180-day period following surgery, Michaels adds. While nosocomial infections are likely to appear in less than 30 days, donor-transmitted infections manifest in the period between 30 and 180 days after the procedure. (See summary of infection time line, above.)
"The fact they have just undergone major surgery to the abdomen for a liver transplant or the thoracic area for heart and lung transplant patients the surgery itself is, as always, the major cause of infection during that [early] time period," she says. "It usually is bacterial and occasionally can be Candida."
Sentinels for infections
Even though such immune-suppressed patients are vulnerable to a variety of infections, surprisingly few special infection control measures are needed during hospitalization if basic aseptic principles are rigorously implemented, she adds.
While Michaels recommends placing transplant patients in private rooms if possible, special air-handling measures like use of high-efficiency particulate air (HEPA) filters are probably only necessary for bone marrow recipients.
"With bone marrow transplant patients, their immune system is completely wiped out, and most of the bone marrow transplant units will have HEPA filtering or laminar flow rooms," she says. "In fact, that is not necessary with an organ transplant. You are not wiping them out [immunologically] to that kind of degree."
In general, no special isolation is necessary after transplantation unless the patient has additional indications, such as colonization with multiply resistant organisms like vancomycin-resistant enterococci (VRE) or methicillin-resistant Staphylococcus aureus (MRSA).
"My feeling is that gowning and gloving is not [as] necessary as appropriate handwashing," Michaels says. "Now if a patient has MRSA or VRE, then you want to have additional [contact] isolation more for the prevention of transmission from that patient to others."
Indeed, nosocomial infections in transplant recipients should be seen as sentinel events, adds Jay Fishman, MD, clinical director of transplantation infectious disease at Massachusetts General Hospital in Boston.
"These people are remarkably sensitive they are sentinels, if you will for infections that are nosocomially derived," he says. "In other words, if you have VRE, MRSA, antibiotic-resistant fungi these are the patients that will have the greatest morbidity and mortality with those."
By the same token, appearance of resistant pathogens and other nosocomial infections in transplant patients may signal problems in other areas of the hospital, he adds.
"While many of these infections are acquired on the [transplant] floor, many of them are also acquired off the floor in places like radiology suites, biopsy suites, operating rooms, intensive care units," he says. "As a result, it is a reflection of the epidemiology of the whole hospital."
While generally no more infectious than any other patient, some transplant patients may harbor pathogens due to the nature of their organ failure, as for example HBV and HCV in patients needing liver transplants, he adds. Likewise, transplant patients known to be colonized with VRE or other drug-resistant bacteria may be asked to gown and glove for routine return visits to the hospital and affiliated clinics, he says.
"In terms of staff handling they need to be thought of carefully," he says. "All patients need to be treated as if they are infected. Universal precautions apply, and if properly observed, they work."
The routine infection control measures taken in the free-standing transplant unit at the hospital include routinely keeping all surfaces free of materials and supplies so they can be frequently cleaned to lessen the likelihood of an environmental source of transmission, Fishman says.
"It is clear that surfaces in patient rooms or at nursing stations provide a nidus for transmission of infection," he says. "We try to minimize the amount of stock that stays in patient rooms, we clean our floors more often, and we are more sensitive to water splashing around sinks as a nidus for fungal infections."
Transplant patients discharged from the hospital are placed on an antibiotic prophylactic regimen geared to the aforementioned time line to prevent the appearance of post-transplant infections, including antibacterial, antifungal, and antiviral prophylaxis regimens for the first six months after transplantation.
"The people are seen at least every month for the first six months, multiple times thereafter for a year or two, and then they are followed on an annual basis as long as things are stable," Fishman says. "We are actively involved in monitoring them for both infection and graft function for the rest of their lives."
References
1. Green MD, Michaels MG. "Solid-Organ Transplanta tion: Infection and Prevention." In: Gower J, ed. APIC Curriculum for Infection Control Practice. St. Louis: Mosby; 1996, pp. 51-1 to 51-8.
2. Gottesdiener KM. Transplanted infections: Donor-to-host transmissions with the allograft. Ann Intern Med 1989; 110:1,001-1,006.
3. Centers for Disease Control and Prevention. Ochrobactrum antropi meningitis associated with cadaveric pericardial tissue processed with a contaminated solution Utah, 1994. MMWR 1996; 671-673.
4. Chang HJ, Christenson JC, Pavia AT, et al. Ochrobactrum anthropi meningitis in pediatric pericardial allograft transplant recipients. J Infect Dis 1996; 173:656-660.
5. Department of Health and Human Services. Draft Public Health Service guideline on infectious disease issues in xenotransplantation. Fed Reg Sept 23, 1996; 49,920-49,932.
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