Summary of Construction-related Nosocomial Infections - Construction-related Nosocomial Infections in Patients in Health Care Facilities

[Table of Contents]

Volume: 27S2 • July 2001

Construction-related Nosocomial Infections in Patients in Health Care Facilities
Decreasing the Risk of Aspergillus, Legionella and Other Infections

A. Summary of Construction-related Nosocomial Infections

A review of the literature of nosocomial infections related to construction or renovation projects in health care facilities is provided. The review spans a 20-year period (1978-1998). It reveals numerous construction-related nosocomial outbreaks, mainly in acute care facilities, and documents the importance of rigorous infection prevention and control practices. As noted in Tables 1 and 2, the majority of infections were related to construction or renovation projects within or adjacent to the health care facility ^{(3-5,7,8,11-15,17-22,24,25,27,29,30,32-34,42,61)}. Others were associated with ventilation systems that were malfunctioning or improperly maintained when the health care facility was undergoing construction or renovation^{(9-11,16,26,62,63)}. Two documented outbreaks of pseudofungemia^(64,65) and one outbreak of pseudobacteremia⁽⁵⁵⁾ occurred when dust particles from construction or renovation projects contaminated laboratory specimens⁽⁶⁴⁾, bronchoscopy material⁽⁶⁵⁾, and blood culture bottles⁽⁵⁵⁾.

Table 1. Summary of the Documented Reports on Construction-related Nosocomial Outbreaks due to Fungus
Etiologic Agent	Underlying Medical Condition of Patients	Number of Patients Infected/ Colonized	Number of Patients who Died	Circumstances	Reference/ Year
A. fumigatus A. niger A. terreus	Burn⁽²⁾ Trauma⁽¹⁾ Perforated viscus and wound dehiscence⁽¹⁾	4	Not available	Renovations in the central inventory control department resulted in Aspergillus spores being dispersed and settling on the supply boxes. The packages inside became contaminated when the box was opened. Patients then became infected when the packages were opened during dressing changes.	Bryce et al., 1996⁽²⁷⁾
A. flavus⁽³⁾ A. fumigatus⁽²⁾ A. niger⁽¹⁾	Leukemia⁽⁶⁾	6	2 (related to underlying illness)	Repair of false ceiling due to a water leak in a store room housing intravenous (IV) supplies. Adhesive tape and arm boards were contaminated.	Grossman et al., 1985⁽²⁵⁾
A. fumigatus⁽¹⁸⁾	Leukemia⁽¹⁵⁾ Myeloma⁽¹⁾ Lymphoma⁽¹⁾ Paramyelosis secondary to breast cancer	22	18	Spores were dispersed during demolition of ducts and false ceilings, removal of fibrous thermal insulating material (glass fibre), and work on roller-blind casings.	Perraud et al., 1987⁽²⁴⁾
A. fumigatus⁽³⁾	Heart transplant⁽³⁾	3	2	Connecting bridge between the old and new unit allowed dust to circulate from a nearby construction project. In addition, one air vent was not properly closed.	Hospital Infection Control, 1990⁽⁶⁶⁾
A. fumigatus A. flavus	Hematologic malignancy⁽²⁾ Advanced age⁽¹⁾ Renal transplant⁽⁷⁾	10 (retro- spective review of autopsy reports)	10 (4 due to invasive aspergillosis)	Window air conditioners in the renal transplant unit were heavily contaminated with Aspergillus spp. The unit was close to adjacent road construction.	Lentino et al., 1982⁽⁹⁾
A. niger A. flavus A. fumigatus	Diagnosis not provided (hospital admits patients with leukemia, lymphoma, myeloma, brain tumours, sarcomas, and metastatic carcinomas)	8	3	Believed Aspergillus spores settled on wet fireproofing material when it was installed during construction. Spores were dispersed when the dry fireproofing material was disturbed above false ceilings during renovation or maintenance.	Aisner et al., 1976⁽¹⁸⁾
A. fumigatus⁽³⁾	Patients on an oncology unit	3	1 (had BMT)	Remodelling of adjacent radiology department. Dust barriers had not been installed.	Berg, 1995⁽⁷⁾
A. fumigatus⁽⁶⁾	Patients in intensive therapy unit for respiratory failure, Crohn's disease, chronic bronchitis, emphysema, asthma, multiple trauma, septic shock, abdominal aneurysm	6	3 (related to underlying disease)	It was suggested that spores in fibrous insulation material above perforated metal ceilings were dispersed during minor building in adjacent offices and stores areas.	Humphreys et al., 1991⁽¹⁴⁾
A. fumigatus⁽⁶⁾	Bone marrow transplantation (BMT)	6	6	Heavy fungal spore contamination resulted from construction of an adjacent BMT unit.	Barnes & Rogers, 1989⁽¹²⁾
A. fumigatus⁽³⁾	Renal transplantation	3	1	Renovation activity on the floor above caused dust to be dispersed from false ceilings in the renal transplant ward.	Arnow et al., 1978⁽⁵⁾
A. fumigatus⁽³⁾	Renal disease - chronic renal failure⁽²⁾ - Wegener granulomatosis	3	2	The outbreak coincided with hospital renovation on a unit near the renal unit on which the patients were being housed.	Sessa et al., 1996⁽¹⁵⁾
A. flavus⁽⁴⁾ A. fumigatus⁽¹⁾ A. niger⁽¹⁾ Other Aspergillus spp	Immunosuppression from - lymphoreticular malignancy⁽⁷⁾ - high-dose corticosteroid therapy⁽³⁾ - disseminated carcinoma⁽¹⁾	11	11	Not provided. Patients were either located on the same floor as or one floor below the construction area.	Opal et al., 1986⁽⁴⁾
A. flavus⁽⁵⁾ A. fumigatus⁽⁶⁾	Patients on a BMT/leukemia unit	13	5	Fire in an old building close to the hospital and repeated window opening by a patient shortly afterwards suggest fungal spores dispersed during the fire were the source. The hall carpet then became contaminated and was an ongoing source of the infection.	Gerson et al., 1994⁽³⁾
A. terreus⁽⁴⁾	BMT⁽²⁾ Acute myelogenous leukemia (AML)⁽¹⁾ Disseminated choriocarcinoma⁽¹⁾ Diagnosis not provided in the remaining 2 patients	6	4	Renovations were taking place two floors below the intensive care unit (ICU). Air pressure in ICU was negative to hallway and nearby elevator shafts. This was thought to have occurred when a wall was built during earlier renovations. In addition, patient room ventilation was conventional rather than unidirectional.	Flynn et al., 1993⁽¹⁰⁾
Aspergillus	Patients on burn unit, dialysis unit and oncology	5	not available	Air intake vents had not been covered during demolition on the nursing units where the patients were housed.	American Health Care Consultants, 1995⁽²⁶⁾
Airborne fungi⁽³⁾ Candida tropicalis⁽²⁾ Fusarium⁽¹⁾	BMT	7	6	Several potential sources included loose wallpaper in a corridor; poorly sealed chase openings and direct opening from BMT rooms with floors above and below; inadequate air exchange and exhausts; negative pressure in 4 of the 16 BMT rooms; high-efficiency particulate- air (HEPA) filters not maintained or changed in 4 years.	American Health Care Consultants, 1995⁽⁶³⁾
Aspergillus	Patients on a hematology unit	5	5	Large-scale excavation work while hospital was being rebuilt. The isolation rooms that housed the patients overlooked the building site.	Shields et al., 1990⁽²⁹⁾
Zygomycetes Aspergillus Rhizopus indicus	Premature infant with respiratory distress syndrome Premature infant with ligation of a patent ductus arteriosus	2	2	Major source of mould was dust above the false ceiling.	Krasinski et al., 1985⁽²¹⁾
Aspergillus	AML⁽²⁵⁾ Acute lymphoblastic leukemia (ALL)⁽⁷⁾ Chronic lymphocytic leukemia (CLL)⁽¹⁾ Chronic myelogenous leukemia (CML)⁽¹⁾ BMT⁽²⁾	36 (over 69 months)	17	Not provided, however, four cases were identified prior to hospital construction compared with 28 cases during construction and four cases after control measures had been initiated, suggesting hospital construction was related to the outbreak.	Loo et al., 1996⁽¹³⁾
A. flavus⁽³⁴⁾	Old cavitary tuberculosis (TB) Diabetes Idiopathic thrombocytopenic purpura (ITP) Leukemia Lung cancer Chronic obstructive pulmonary disease (COPD) Bacterial pneumonia	32	1	Construction activity adjacent to the hospital and a defective ventilation system in old wing of hospital (e.g. prefilters heavily soiled, gaps between the individual filters and framework). Unfiltered air was allowed to enter patient care areas.	Sarubbi et al., 1982⁽¹¹⁾
Aspergillus	Immunosuppressive treatment for vasculitis	3	3	Construction work and demolition of hospital buildings adjacent to the medical unit the patients were on. Contributing factors: no special ventilation system and windows could not be completely closed.	Dewhurst et al., 1990⁽²⁰⁾
A. flavus⁽⁶⁾ A. fumigatus⁽¹⁾ Mucoraceae rhizopus⁽¹⁾	AML⁽³⁾ ALL⁽³⁾ Aplastic anaemia⁽¹⁾ Metastatic Wilm's tumour⁽¹⁾	8	5	Directly related to increased spore counts from soil excavation that occurred during hospital construction in a pre-existing facility.	Lueg et al., 1996⁽¹⁷⁾
Aspergillus⁽³⁾ Zygomycetes⁽²⁾	Burkitts's lymphoma⁽¹⁾ AML⁽¹⁾ ALL⁽³⁾	5	5	Exposure to construction activity was independently associated. Extensive renovation was taking place as well as new construction. Windows could be opened on the unit the children were on, and the "reversible pressure" system did not provide the indicated pressure relationships.	Weems et al., 1987⁽¹⁶⁾
A. fumigatus⁽²⁾ A. flavus⁽¹⁾ Unknown⁽²⁾	Neutropenia as a result of high-dose chemotherapy	5	not provided	There was a significant increase of mould in the air in the patient rooms and corridors after construction was started. Sealing windows and other areas suspected of causing leaks decreased the amount of mould in the air. Therefore, leaks around windows were suspected to be the major source.	Iwen et al., 1994⁽⁸⁾
Scedosporium prolificans (inflatum)⁽⁴⁾	AML⁽³⁾ ALL⁽¹⁾	4	4	Source is unknown. The patients were housed in two isolation rooms at the entry to the unit, which was opposite to the construction zone.	Alvarez et al., 1995⁽⁴²⁾
Sporothrix cyanescens*	Pneumonia with abnormal chest x-rays that required bronchoscopy with biopsy⁽⁴⁾	4	0	Dust from renovation activity within and adjacent to a bronchoscopy unit contaminated the specimens or specimen containers stored in the bronchoscopy suite.	Jackson et al., 1990⁽⁶⁵⁾
Aspergillus penicillium*	Diabetes, hyaline membrane disease, asthma, meconium aspiration, cerebral palsy, Wilms' tumour, ALL, bronchiolitis	13	0	Agar plates were left open to air and were not processed under laminar hood. Spores entered the laboratory through a false ceiling that was connected to the renovation area. In addition, air was drawn in because of the negative pressure within the laboratory.	Hruszkewycz et al., 1992⁽⁶⁴⁾
Note. * These examples represent cases of pseudoinfection.

Table 2. Summary of the Documented Reports on Construction-related Nosocomial Outbreaks due to Bacteria
Etiologic Agent	Underlying Medical Condition of Patients	Number of Patients Infected/ Colonized	Number of Patients who Died	Circumstances	Reference/ Year
Nocardia asteroides⁽⁷⁾	Chronic liver disease⁽⁴⁾ Liver transplant⁽³⁾	7	6	Considerable amounts of dust were visible on ward surfaces and equipment. Renovations were being done on the unit at the time. Environmental screening was negative for Nocardia spp.	Sahathevan et al., 1991⁽⁶¹⁾
Legionella pneumophila	One patient had myelodysplasia and neutropenia and was admitted for dental extraction. The other was admitted for gastrointestinal bleed.	2	2	A water valve in the potable water supply was turned off near the area of soil excavation. Authors believe repressurization of the water supply after the valve was reopened may have caused massive descalement inside the pipe and led to the outbreak.	Mermel et al., 1995⁽³⁴⁾
Legionella bozemanii⁽⁴⁾	Lymphoma⁽²⁾ Uremia⁽¹⁾ Rheumatoid arthritis⁽¹⁾ ITP⁽¹⁾	5	0	Soil entered the water supply during construction and installation of new plumbing.	Parry et al., 1985⁽³²⁾
Legionella spp	20 of the patients were immunocompromised	49 (3 employees)	15	Aerosols from soil excavation or water-cooling towers were considered to be the source.	Haley et al., 1979⁽³⁰⁾
Not reported (CDC found serologic evidence of legionnaires' disease)	Psychiatric illnesses	81	14	Source was suspected to have been derived from soil excavation on hospital grounds of a pre-existing facility.	Thacker et al., 1978⁽³³⁾

1. Etiologic Agents

As shown in Tables 1 and 2, construction-related nosocomial infections are primarily due to fungi and, to a lesser extent, bacteria. The predominant etiologic agent is Aspergillus. In particular, Aspergillus fumigatus^{(3-5,7-9,13-15,17,23-25,27,41,62,67)}, A. flavus^{(3,4,8,9,11,13,17,25)}, A. niger^{(3,4,8,9,13,17,27)}, and A. terreus^(10,27) have been repeatedly documented. Other fungi implicated include Candida tropicalis⁽⁶³⁾, Candida parapsilosis⁽²¹⁾, Fusarium⁽⁶³⁾, Zygomycetes^(16,21), Rhizopus indicus⁽²¹⁾, Mucoraceae rhizopus⁽¹⁷⁾, and Scedosporium prolificans⁽⁴²⁾. The major bacteria were Legionella spp^(30,32-34), including L. pneumophila⁽³⁴⁾ and L. bozemanii⁽³²⁾. Nocardia asteroides⁽⁶¹⁾ is another bacterium reported to have caused outbreaks. There were also two identified cases of pseudofungemia, one caused by Sporothrix cyanescens⁽⁶⁵⁾ and the other by Penicillium⁽⁶⁴⁾, as well as one case of pseudobacteremia caused by Bacillus spp⁽⁵⁵⁾. Since Aspergillus and Legionella species are the most frequent causes of construction-related nosocomial infection, they will be described in more detail. Understanding the relation between these organisms and construction and renovation activities leads to a better understanding of the need for preventive measures.

Aspergillus organisms are fungi found ubiquitously in soil, water, and decaying vegetation^(36,40). The fungal spores (conidia) proliferate on dead organic debris⁽⁶⁸⁾ and can remain viable for months in dry locations⁽⁶⁹⁾. During construction and renovation activities, spores can be dispersed on dust or dirt particles when floors, walls, or ceilings are penetrated⁽¹⁾ . Since Aspergillus spores are small (2.5 mm-3.5 mm) and settle very slowly (0.03 cm per second), they can remain suspended in air for prolonged periods⁽⁶⁹⁾. This increases the likelihood that they will be inhaled or will contaminate environmental surfaces.

Normally, Aspergillus species are transient colonizers in humans⁽⁷⁰⁾. The small size of the conidia allows the organisms to bypass the host defences of the upper airway and to reach the pulmonary alveolar spaces⁽⁷⁰⁾. Three main processes may occur when Aspergillus spores reach the lungs: colonization, hypersensitivity, or invasive infection⁽⁷¹⁾. The host's response determines the manifestations of disease⁽⁷¹⁾. Healthy individuals, such as health care workers, may become sensitized to Aspergillus but have only a minute risk of infection if exposed⁽⁷²⁾, whereas exposure to Aspergillus can be life-threatening and often fatal for patients who are severely immunosuppressed^(36,37,73). Assigning a clinical diagnosis of invasive pulmonary aspergillosis may be difficult, as early signs are nonspecific and the rate of isolation of the organism in sputum cultures is low⁽⁷⁴⁾. It is essential that preventive measures to decrease patients' or residents' exposure to dust particles contaminated with aspergillus spores be undertaken. This is especially important for patients who are granulocytopenic⁽⁷⁵⁾.

Legionella is also a ubiquitous organism⁽⁴⁵⁾. This gram-negative, aerobic, rod-shaped bacterium is found in natural aquatic environments⁽⁴⁵⁾ as well as in soil and dust⁽⁷⁶⁾. Reservoirs in hospitals have included cooling towers, evaporative condensers, locally produced distilled water, heated potable water systems, and heating and air-conditioning systems^{(36,45,77,78)}. During construction and renovation projects, water systems are often disrupted and the potable water can become contaminated with Legionella when the water supply is restored⁽¹⁾. Contamination may be related to massive descaling in the water pipes as they are repressurized⁽³⁴⁾ or to the introduction of contaminated soil into the plumbing system⁽³²⁾. Legionella can then proliferate in the facility's water supply if certain conditions exist, such as sediment in hot water tanks⁽⁷⁹⁾, low hot-water temperatures at faucets⁽⁷⁸⁾, and water systems that are prone to stagnation^{(77,78,80,81)}. In addition, soil and dust containing dormant forms of Legionella can become airborne during soil excavation and can subsequently contaminate cooling towers⁽⁷⁶⁾ or be inhaled by susceptible patients^(30,32,33). The occurrence of a nosocomial infection caused by Legionella depends on the resistance of the host, exposure of the host to a contaminated source, and the degree of contamination of the source^{(44,46,82,83)}. Patients receiving high dose steroids are at particular risk. Legionnaires' disease is thought to be acquired by inhalation of aerosols contaminated with Legionella from the water supply^(83-85). Legionnaires' disease can be difficult to diagnose if not suspected^(80,84) because specialized laboratory methods and culture media are required⁽⁸²⁾. Thus, preventive measures to decrease the transmission of Legionella should be implemented when construction or renovation activities that disrupt some of the health care facility's water supply are planned.

2. Source of the Microorganism Causing Infection in Construction Settings

Biological sources causing infection in construction settings include mould, dust, or soil contaminated with fungal spores or bacteria. Contaminated mould or dust particles have been reported to come from above false ceilings^{(5,21,24,25,64,86)}, fibrous insulating material^(14,24), roller-blind casings⁽²⁴⁾, and fire-proofing material⁽¹⁸⁾. An outbreak of aspergillosis occurred after a fire demolished an old building adjacent to a hospital's bone marrow transplantation unit. The outbreak was believed to be caused by fungal spores, dispersed during the fire, entering the hospital through an open window and contaminating the hall carpet⁽³⁾. Other outbreaks have been reported when contaminated dust particles infiltrated adjacent patient care areas where no impermeable barrier had been erected⁽⁷⁾ or windows had not been properly sealed^(8,16). Cutaneous aspergillosis developed in four patients when dressing supplies were used that had been contaminated during construction activities in a central inventory area⁽²⁷⁾. Soil excavation was also suspected of dispersing fungal spores^(9,17,22,29) or bacteria^(30,32,33) into the air, which were then inhaled by susceptible patients.

Outbreaks have been related to the hospital's plumbing or ventilation system. Leaking water pipes caused water damage to the false ceiling in an IV supply storeroom⁽²⁵⁾. During renovations to repair the ceiling, dust and mould particles were dispersed and contaminated the IV supplies. The contaminated supplies were used in treating children with leukemia, some of whom developed cutaneous aspergillosis⁽²⁵⁾. An outbreak of legionellosis was reported following the installation of new water pipes ⁽³²⁾. It is possible that soil contaminated with Legionella entered the water supply at the time the new pipes were connected to the existing hospital plumbing system⁽³²⁾. In another example, legionnaires' disease occurred after the repressurization of the water supply when a valve near the area of soil excavation was reopened after being closed⁽³⁴⁾. The sudden surge of water was thought to have caused a massive descalement inside the water pipes, which led to the outbreak⁽³⁴⁾.

A construction-related nosocomial outbreak of A. flavus occurred when a defective ventilation system allowed unfiltered air from an adjacent construction zone to circulate into patient care areas. Prefilters were heavily soiled, and gaps were found between the individual filters and framework⁽¹¹⁾. Hospital ventilation systems have been implicated in the development of nosocomial fungal outbreaks during periods of construction or renovation when 1) vents were not closed properly^(26,62); 2) incorrect air pressurization in patient care areas allowed airflow to move from dirty areas to clean areas^(10,16,63); 3) air exchange and exhaust were inadequate⁽⁶³⁾; or 4) HEPA filters were not properly maintained⁽⁶³⁾. Finally, an outbreak of aspergillosis was related to a heavily contaminated window-mounted air conditioner that was adjacent to a road construction project⁽⁹⁾.

As this review illustrates, a variety of sources of infection exist in health care facilities during construction and renovation activities. When such activities are being planned, health care personnel and other professionals involved must consider potential sources of highly concentrated microorganisms that may cause nosocomial infections.

3. Risk Factors for Construction-Related Nosocomial Infections

A. Exposure to Construction

Any patients exposed to health care facility construction activities or soil excavation may be at increased risk of acquiring a construction-related nosocomial infection. Weber and colleagues found that hospitalization during construction was an independent risk factor for development of invasive nosocomial fungal infection (p = 0.09)⁽²³⁾. Similarly, Weems and associates demonstrated that the incidence of invasive aspergillosis or zygomycosis was significantly higher during construction periods (p = 0.001 Fisher's Exact Test)⁽¹⁶⁾. Klimowski and colleagues reported an increased incidence of aspergillosis over 20 years that coincided with the increasing number of internal hospital renovation projects and, to a lesser extent, external construction projects⁽¹⁹⁾. Soil excavation and construction have also been identified as risk factors in an outbreak of L. bozemanii⁽³²⁾. Thacker and associates showed a relation between patients who were allowed access to the hospital grounds at the time of soil excavation and risk of acquiring legionnaires' disease (p < 0.0001)⁽³³⁾. Thus, the importance of decreasing patients' exposure to construction activities or soil excavation is well documented.

B. Patient characteristics

Certain patients are at increased risk of construction-related nosocomial infections because of underlying medical conditions. Comorbidity is one of the best predictors of the development of invasive aspergillosis⁽⁸⁷⁾ or legionnaires' disease^(36,50).

A brief description of the immune response to fungal and bacterial organisms is provided to help the reader understand the relation between the underlying medical condition and development of infection. When a person with a healthy immune system is exposed to Aspergillus, macrophages kill the conidia (spores), and neutrophils provide a defence against the mycelia. When a host has granulocytopenia (very low numbers of neutrophils), an increased likelihood of invasion of tissue by Aspergillus can occur⁽¹⁵⁾. The duration of granulocytopenia is an independent risk factor for invasive nosocomial fungal infections (p < 0.01)⁽²³⁾. Neutrophils play a less important role in the defence against Legionella that reach the lungs. Consequently, granulocytopenic patients are not at excessive risk for legionnaires' disease⁽⁸¹⁾.

Immunosuppressive conditions identified as risk factors for construction-related nosocomial fungal infections include graft-versus-host disease requiring treatment^(36,87-89); prolonged neutropenia or granulocytopenia because of cytotoxic chemotherapy^{(3,15,17,22,23,42,87,88,90)}; prolonged use of antibiotics^{(15,17,42,87,88)}; and steroid therapy^(87,89). Other risk factors for the development of aspergillosis include dialysis and mechanical ventilation⁽⁴³⁾, smoking⁽⁸⁷⁾, and patient age⁽⁸⁸⁾, the very young and very old being at greater risk^(21,87). Grauhan and colleagues reported that the risk of a fungal infection increases in patients who exhibit three or more risk factors (p < 0.001)⁽⁴³⁾.

Similarly, immunosuppressive therapy for organ transplantation, immunodeficiency diseases, steroid therapy^{(32,44,46,54,77,81,84,85,91)}, and advanced age are risk factors for acquiring and dying from legionnaires' disease⁽³⁶⁾. Males may be at greater risk^{(33,44,77,84,85,91)}, since more men than women are reported to have acquired legionnaires' disease. Additional risk factors for legionnaires' disease include smoking^{(44,77,84,85,91)}, excessive use of alcohol^(77,84), surgery⁽⁸⁵⁾, diabetes^(84,91), and neoplastic, pulmonary, renal, or cardiac disease^{(44,46,81,84,91)}.

In summary, patients with any of the risk factors listed in Table 3 may be at greater risk for nosocomial infections during construction and renovation activities. Immunosuppressed patients are at greatest risk of acquiring a nosocomial fungal infection or legionellosis^{(3,7,15,32,42,81,84,89,91)}. This includes patients who have undergone bone marrow or solid organ transplantation, oncology patients who are receiving chemotherapy, patients receiving dialysis, and patients taking immunosuppressive medication, including steroids. Such high risk individuals may receive care in health care facilities across the continuum of care, e.g. oncology patients in ambulatory units; thus there is a need for a risk assessment prior to construction and renovation activities wherever health care is provided.

Table 3. Patient Risk Factors for Construction-related Nosocomial Infections

Risk Factors for Infections with Filamentous Fungi

Risk Factors for Legionnaires' Disease

1.	Exposure to construction activities
2.	Immunosuppressive conditions (e.g. bone marrow or solid organ transplantation; graft-versus-host disease requiring treatment; prolonged neutropenia or granulocytopenia because of cytotoxic chemotherapy; prolonged use of antibiotics to treat fevers or previous infections; and steroid therapy or other immunosuppressive therapy)
3.	AIDS, congenital immunodeficiencies
4.	Dialysis, renal failure
5.	Diabetic ketoacidosis
6.	Mechanical ventilation
7.	Smoking
8.	Age of the patient (e.g. neonates and very old patients have a greater risk)

1.	Exposure to soil excavation during construction and malfunction of plumbing systems
2.	Immunosuppressive conditions (e.g. bone marrow or organ transplantation; graft-versus-host disease requiring treatment; and steroid therapy)
3.	Advanced age
4.	Chronic pulmonary disease
5.	Smoking
6.	Excessive use of alcohol
7.	Surgery
8.	Diabetes
9.	Neoplastic disease
10.	Renal failure
11.	Cardiac failure

[Previous] [Table of Contents] [Next]


	Last Updated: 2001-08-15		Important Notices