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Saudi Journal of Kidney Diseases and Transplantation
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Year : 2005  |  Volume : 16  |  Issue : 4  |  Page : 547-555
Infection Control and the Immunocompromised Host


King Fahad National Guard Hospital, King Abdulaziz Medical City, Riyadh, Saudi Arabia

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How to cite this article:
Alothman A. Infection Control and the Immunocompromised Host. Saudi J Kidney Dis Transpl 2005;16:547-55

How to cite this URL:
Alothman A. Infection Control and the Immunocompromised Host. Saudi J Kidney Dis Transpl [serial online] 2005 [cited 2017 Mar 24];16:547-55. Available from: http://www.sjkdt.org/text.asp?2005/16/4/547/32846

   Introduction Top


Immunocompromised patients are at high risk for opportunistic infections. Traditionally, there are infections that arise from endogenous reactivation of latent infections, and nosocomial transmission. Therefore, it is deemed likely that special infection control (IC) interventions are required to prevent transmission in health­care settings. [1]

Epidemiological investigations and air­sampling experiments lend support to the hypothesis that reinfection with a pathogenic organism does occur, airborne transmission is possible and nosocomial spread is a plausible explantation for new cases in immunocom­promised population. [2],[3],[4] These observations support the view that infectious complications in immunocompromised patients are exogenous in origin and more epidemiological studies are needed to define the risk of nosocomial spread and need for better infection control practices to prevent these infections.

The fact that infectious complications in immunocompromised patients are often pre­dictable and may be preventable makes infection control practices a very important step in the improvement of the quality of care provided to such patients. [5],[6]

In addition, by reducing infectious morbidity, infection control practices will contribute significantly to cost savings.


   Who is the Immunocompromised Host? Top


The immunocompromised host is a person with one or more defects in the body's normal defense mechanisms that predispose him to infections, often life-threatening, which would not otherwise occur. The categories of host defects that are commonly associated with impaired resistance are listed in [Table - 1].


   Risk for Developing an Infection Top


The immunocompromised patient's risk is best evaluated by defining the net state of immunosuppression and is determined by the interaction of multiple factors including: 1) the underlying disease, 2) the patients' age, 3) the dose and duration of immunosuppression therapy, 4) the state of humoral and cellular host defences, 5) the integrity of the skin and mucosal membrane, 6) metabolic factors, 7) abnormalities of the reticuloendothelial system, and 8) the presence of immunomodulating infections, such as those caused by cytomegalo­virus, and Epstein-Barr virus. [7]


   Interventions to Prevent Infections in the compromised patient Top


Interventions have been categorized into two kinds: pre-emptive and concurrent measures. Pre-emptive measures:

  1. Identification and correction of risk factors
  2. Augmentation of host resistance to infection [9],[10],[11],[12]
  3. Avoidance of hospitalization [13]


However, Concurrent measures could include:

  1. Reduction of exposure to exogenous pathogens.
  2. Reduction of endogenous flora e.g. neutropenia [14],[15]
  3. Antimicrobial prophylaxis [15],[16]


This article will evaluate the reduction of exposure to exogenous pathogens:

Food

Fresh fruits and vegetables appear to carry several species of gram-negative rods as part of their natural flora. [5],[17],[18] . It has been demonstrated that several kinds of salads were colonized by Pseudomonas aeuroginosa, E. coli and Klebsiella spp. [19]

The cooked food diet or the low bacterial diet is recommended to reduce the exposure of immunocompromised patients to these potential pathogens. [5],[20],[21],[22] Gamma-irradiation has been implemented successfully to eliminate viable bacteria with no health hazard to the patient. [23]

Water

Water has known potential as a vehicle of infectious diseases transmission. Several micro­organisms have been shown capable of repli­cation in water. In addition, water and ice have been proven sources for nosocomial outbreak of infection. [24]

It is known that neither tap water nor hospital water are sterile. Hospital water should have < 1 coliform bacterium/ 100ml, levels higher than that in hospital water. Dialysate water, sinks, faucets and shower heads have been associated with disease outbreaks or hand colonization. [25]

Patterson et al have reported that Legionella spp. were isolated from the water supplies in 55% transplant units. Furthermore, free-living protozoa were isolated from water supplies in 68% transplant units. [26] They concluded that the quality of cold water may be improved by provision of a dedicated supply taken directly from the incoming mains, and of hot water by the use of a calorifier, able to main­tain a minimum circulating hot water return temperature of 60 o C. Another study of how safe is potable water for hospitalized immuno­compromised patients concluded that end­line commercially available water filters were the optimal way to provide drinking water to such patients. [27]

In general, it is recommended that whenever possible, the immunocompromised patient should avoid tap water and ice made from tap water. [5]

Plants and Fresh Flowers

Fresh flowers and other plants can carry microorganisms that are pathogenic for the immunocompromised patient. [5] A study showed that flowers and related items were colonized by over 40 different species of bacteria. Over­all, 90% of the isolated organisms were known as causative agents of infection. [28] The authors recommended that:

i) Ban flowers in high-risk areas, such as cancer wards and burn units.

ii) Designate handling of flowers to support staff with no patient contact.

iii)Hand washing after contact with plant materials

iv) Change vase water at least every 48 hours

v) Dispose vase water into designated sinks.

Handwashing

Handwashing is an important modality for prevention of infection and should be done by patients, visitors and healthcare workers. [29] It is known that simple soap-and-water hand­washing will remove almost all transient gram­negative rods in 10 seconds. Regretfully, most doctors and nurses in intensive care units do not wash their hands after each patient contact. On average, compliance with recommended hand washing is only 40 % in intensive care units. [30]

Alcohol may be as good as or better than simple soap-and-water handwashing for remov­ing transient bacteria. However, chlorhexidine may be better than non-medicated soaps for removal of transient gram-positive orga­nisms. [30],[31]

Patients and visitors should be taught proper techniques of handwashing and encouraged to do so before and after contact.

Handwashing Related Issues

The nature of job of health care workers requires an infection control department to watch not only the worker but also their performance of a certain duty.

i) Gloves: Studies have shown extreme vari­ability in the quality of disposable gloves. Vinyl gloves have a leakage rate of 4­63% [32],[33],[34] In addition, latex gloves have a leakage rate of 3-52% . [32],[33],[34],[35]

The increased moisture content from per­spiration of the hand after wearing glove will increase bacterial counts. [5] It is advisable that handwashing should take place after gloves removal.

ii) Jewelry: Field et al compared bacterial counts from skin under rings and watches of dental surgeons and non-clinical staff. Both groups showed a significantly greater number of bacteria isolated from skin under rings and watches compared to control sites. [36] Rings and other jewelries have been shown to have total bacterial counts on hands higher when jewelry is worn. [37],[38]

It was recommended that rings and other jewelry should be removed prior to hand disinfection and donning of gloves.

iii)Fingernails and artificial nails: Gram-negative rods have increased growth under artificial nails. [39] Short nails are preferable, because the majority of bacteria are found under and around fingernails. [5]

Visitations

Visitors of immunosuppressed patients should be screened by health care providing team. Those who are currently suffering either from a diagnosed illness that is communicable by airborne, droplet nuclei or contact routes, or who have symptoms of viral illness should be discouraged from visiting immunocompromised patients. Appropriate infection control pre­cautions for visiting the immunosuppressed patients should be employed. [40]

It is also advisable that visitors under the age of 12 years be permitted only with physician approval even if they appear healthy because of the high incidence of subclinical viral and non-viral illness in the age group. [41] Pediatric visitors should be screened for known illness or exposure in the previous month to: varicella, rubella, measles, mumps, hepatitis A, hepatitis E, streptococcal pharyngitis, pertussis, upper respiratory tract infections, diarrhea, fever, skin rash or attenuated live viral vaccination (MMR, varicella vaccine or oral polio).

Pet Therapy

Some authorities have advocated pet therapy as psychologically beneficial for patients. [42] However, pets in health care institutions pose potential serious infection control hazards because of organisms that may be transmitted to humans. [5] Certain circumstances argue against allowing pet visitations. For example patients who had a splenectomy are at high risk for invasive infection from oral flora of dogs, e.g. Capnocytophaga canimorsus. Also, some pets can act as fomites for the transmission of bacteria between patients. Patients who are situated in contact isolation should not be allowed to interact with animals [5],[42]

Control of Environmental Factors

It is well established that environmental sources can contribute to colonization and infection by several microorganisms, parti­cularly in immunocompromised patients. [43] Environmental sources that are to be considered are air, water, and inanimate surfaces surround­ing the patient. Air contaminated by fungal spores can lead to invasive aspergillosis, water contaminated by Legionellea pneumophila can cause legionnaire' disease and contami­nated inanimate surfaces may result in the acquisition of Clostridium difficile.

Invasive aspergillosis remains a life-threat­ening infection in immunocompromised patient despite the newly developed antifungal medi­cations. [44],[45] If the immunocompromised patients need to be admitted to a hospital, they should be placed in rooms equipped with high-effi­ciency particulate air (HEPA) filters [46],[47],[48] In addition, water should be properly disinfected (chlorination, superheating, ozonization or other methods) to avoid infection by certain bacteria e.g. Legionella pneumophila or certain protozoa like Cryptosporidium par­vum[26],[27],[49].

Adequate disinfection of endoscopes and other inanimate objects that can serve as vehicles for transmission of C. difficille can significantly reduce the incidence of C. difficile diarrhea. [50],[51] The disinfections of patient areas with phosphate-buffered hypochlorite or aldehyde-containing disinfectants has been shown to be highly effective in decreasing environmental contamination and is recom­mended on wards and rooms involving Clos­tridium difficile carriers. [52]

Isolation

Immunocompromised patients vary in their susceptibility to nosocomial infections, depend­ing on the severity and duration of immuno­suppression. Generally, these patients are at increased risk for infection from both endo­genous and exogenous sources. [5],[15] Ideally, if the standard precautions for all patients and transmission-based precautions for a specified patient get applied properly, the end result will be a reduction in exposing the compromised host to pathogenic organisms.

Isolation procedures are needed by 7-12% of patient admitted to hospitals. However, only 17-43% of the patients who should be isolated do so. Only half of isolation procedures are maintained for those started on isolation. [53],[54]

There are three basic kinds of isolation; contact, airborne (respiratory) and droplet isolation, depending on which organism has caused an infection in a patient. [54]

For neutropenic patients, most hospitals use a form of protection isolation. This has ranged from total protective environment (TPE) to simple reverse isolation with standard pre­cautions. [5] Currently, the only circumstance in which TPE is recommended, is for patients who are post allogeneic bone marrow trans­plantation for severe aplastic anemia. [55]

Burn units, still rely heavily on more complete barrier-precautions i.e. gowns, gloves, masks and surgical caps.

Medical Instruments and Patient Areas

It has been demonstrated that necessary instruments to health care providers may be colonized by hospital bacteria. These instru­ments can serve as vectors for cross-trans­mission among patients if not properly disinfected. [56],[57]

It was also shown that some parts of the hospital environment have served as reservoir for multiple organisms. [58] Possible reservoirs of infectious agents are summarized in [Table - 2]. For example, Bernard et al have shown that among 355 stethoscopes 54 were significantly contaminated (≥ 20 cfu/membrane). The investi­gators recommended systematic disinfection of stethoscopes with 70% alcohol or liquid soap, or the use of disposable covers to minimize the chance of spreading nosocomial pathogens. [59]

Patient Hospital Charts

Marinella et al have shown that patients' hospital charts are contaminated by several bacteria. [60] An investigative study in a tertiary care hospital showed that patient hospital charts are contaminated by coagulase-negative Staphylococcus in 100%, gram positive bacilli in 75% and also methicillin-resistant Staphylo­coccus aureus in 2%. [61]

It is recommended that health care workers should wash their hands before and after contact with the chart. Also, patients' hospi­tal charts should not be allowed inside the patients' rooms and should remain on the chart rack.


   Conclusions Top


The care of immunocompromised hosts is evolving with new therapies, emerging infe­ctious complications and changes in health care delivery. On the other hand, the level of education of the population being served and the presence of endemic infectious diseases in that geographic location are important factors. All of these factors need to be consi­dered in more studies in the field of infection control and the compromised patients.[61]

 
   References Top

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Correspondence Address:
Adel Alothman
Consultant, Infectious Diseases, King Fahad National Guard Hospital, King Abdulaziz Medical City, P.O. Box 22490, Riyadh 11426
Saudi Arabia
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