Invasive aspergillosis in acute leukemia: correlation with nose cultures and antibiotic use

Aerosol amphotericin B is effective for prophylaxis and therapy in a rat model of pulmonary aspergillosis

Invasive pulmonary aspergillosis is a major life-threatening complication among transplant recipients and patients receiving cancer chemotherapy. In a rat model of progressive pulmonary aspergillosis that is characterized by hyphal bronchopneumonia, aerosol amphotericin B (aero-AmB; 1.6 mg/kg given 2 days before infection) significantly delayed mortality in rats compared with animals in a control group. The first death in the aero-AmB-treated group occurred on day 11, by which time seven of the eight control animals had died. The same dose of aero-AmB given as treatment (1.6 mg/kg given 24 h after infection and then daily for 6 days) was also effective. In this trial, eight of the ten animals treated with aero-AmB survived for 7 days, whereas only one of ten control animals survived. Colony counts in lung homogenates obtained 24 h after infection showed an 80-fold reduction in the number of viable spores in animals that had received 6.4-mg/kg doses of aero-AmB 2 days prior to infection. At 48 h after administering a single 1.6- or 3.2-mg/kg dose of aero-AmB, mean lung concentrations were 2.79 and 5.22 micrograms/g of tissue, respectively. We conclude, therefore, that aero-AmB kills inhaled spores and delays the progression of pulmonary aspergillosis by inhibiting mycelial proliferation.

Fungal infections of the immunocompromised host: clinical and laboratory aspects

Fungal infections of the immunocompromised host are being seen with greater frequency than ever before. In addition, a growing list of unusual and unexpected etiologic agents presents a unique and difficult challenge to the clinician and microbiologist. The clinical manifestations of opportunistic fungal infections are often not characteristic and, in many instances, may prevent a rapid diagnosis from being made. Clinical microbiology laboratories should consider any organism as a potential etiologic agent. This requires that all fungi recovered from immunocompromised patients be thoroughly identified and reported so that their clinical significance may be assessed. This review presents a brief discussion of the clinical and laboratory aspects of some fungal infections seen in this important group of patients.

Infectious complications in childhood acute leukemias

Infectious complications in children with acute leukemias are reviewed as to incidence, predisposing factors, microbiologic etiologies and treatment. Principles of antimicrobiologic therapy are presented for bacterial, fungal, viral, and protozoal infections seen in children with cancer. Prevention of infection is also discussed.

An approach to intensive antileukemia therapy in patients with previous invasive aspergillosis

PURPOSE

In an attempt to decrease the risk for reactivation of life-threatening invasive aspergillosis (IA) during subsequent myelosuppression in patients with previously diagnosed IA who were receiving antileukemic treatment, we evaluated the role of intensive antifungal therapy with amphotericin B and 5-fluorocytosine administered prophylactically throughout the antileukemic regimen and induced granulocytopenia to prevent IA reactivation without compromising the intensive chemotherapy.

PATIENTS AND METHODS

During a 30-month period, 10 patients with acute myelogenous leukemia and primary IA developing during initial antileukemia induction therapy and severe granulocytopenia (less than 100/mm3) underwent 14 subsequent courses of intensive marrow aplasia-producing chemotherapy during early complete remission or at leukemia relapse. All patients had evidence of ongoing IA healing by lung computerized tomography (CT) prior to reinstitution of intensive chemotherapy. Nine patients receiving 13 chemotherapy courses also received aggressive prophylactic anti-IA therapy with amphotericin B (1.0 mg/kg/day) and 5-fluorocytosine beginning at least 48 hours prior to antileukemia therapy institution and continued until the time of granulocyte recovery.

RESULTS

All nine patients receiving aggressive antifungal therapy survived without clinical evidence of IA reactivation. Transient radiographic evidence of IA reactivation during granulocytopenia was detected by lung CT during two of the 13 chemotherapy courses. In contrast, the patient who did not receive anti-IA prophylaxis had both clinical and radiographic evidence of IA reactivation during severe granulocytopenia and died. Anti-IA prophylaxis was achieved without irreversible nephrotoxicity, prolonged marrow suppression, alteration of antileukemia treatment, or negative impact on clinical outcome relative to acute leukemia.

CONCLUSION

This approach of antifungal prophylaxis in adults with acute leukemia and documented primary IA occurring during initial induction chemotherapy has been successful in preventing clinically significant IA reactivation during subsequent granulocytopenic courses, and allows for administration of additional intensive antileukemia therapy.

Fatal aspergillosis associated with smoking contaminated marijuana, in a marrow transplant recipient

A 34-year-old man presented with pulmonary aspergillosis on the 75th day after marrow transplant for chronic myelogenous leukemia. The patient had smoked marijuana heavily for several weeks prior to admission. Cultures of the marijuana revealed Aspergillus fumigatus with morphology and growth characteristics identical to the organism grown from open lung biopsy specimen. Despite aggressive antifungal therapy, the patient died with disseminated disease. Physicians should be aware of this potentially lethal complication of marijuana use in compromised hosts.

Elastase production in clinical isolates of Aspergillus

Clinical isolates of Aspergillus species were tested, both retrospectively and prospectively, for elastase activity using rose bengal-elastin agar plates. Patient records were then reviewed to determine the clinical diagnosis including the presence or absence of aspergillosis. All isolates that caused invasive aspergillosis produced elastase, but not all isolates producing elastase were associated with invasive disease.

Invasive aspergillosis in a patient with aplastic anemia receiving amphotericin B

Invasive mycotic infections are becoming more commonplace in immune-compromised hosts. Aspergillus species is the most commonly encountered fungal genus in our environment causing paranasal sinus fungal infection. Aspergillus paranasal sinus infections in the healthy host are readily treated and controlled. In the immune-compromised host this common organism can rapidly become fatal even if recognized and treated appropriately. We present a case history of a patient who died from her disease despite radical surgery and antifungicidal therapy. Recent methods for early diagnosis will be reviewed. Only one other case has been reported in the literature of a patient developing fulminant aspergillosis sinusitis while receiving amphotericin B.

Primary cutaneous aspergillosis associated with Hickman intravenous catheters

We describe nine patients with underlying hematologic cancer in whom primary cutaneous aspergillosis developed at the sites of Hickman intravenous catheters. Our patients, 17 to 74 years of age, were all immunocompromised either from their primary disease or from chemotherapy, and the Hickman catheters had been placed to provide venous access for chemotherapy or hyperalimentation or both. Clinical signs of infection included erythema, induration, and cutaneous or subcutaneous necrosis at the point of entry into the subclavian vein, in the subcutaneous tunnel, or at the exit site from the skin. Diagnosis was confirmed by positive wound culture for Aspergillus flavus in all but one patient. Treatment consisted of intravenous amphotericin B, oral flucytosine, and local wound care. Three patients recovered completely without operative débridement; three others recovered after operative débridement and delayed grafting. Two patients died of disseminated aspergillosis, and one died of unrelated causes while recovering from primary cutaneous aspergillosis. Successful treatment required resolution of aplasia or leukopenia, catheter removal, systemic treatment with amphotericin B, and local wound care. We conclude that primary cutaneous aspergillosis, a rare infection, may occur at the sites of Hickman catheters in immunocompromised patients, and that it is a serious complication requiring prompt diagnosis and treatment.

Impact of air filtration on nosocomial Aspergillus infections. Unique risk of bone marrow transplant recipients

Bone marrow transplant recipients were found to have a 10-fold greater incidence of nosocomial Aspergillus infection than other immunocompromised patient populations (p less than 0.001) when housed outside of a high-efficiency particulate air (HEPA) filtered environment. Multivariate analysis demonstrated that number of infections, age, and graft-versus-host disease severe enough to require treatment were independent risk factors for development of nosocomial Aspergillus infection in this group. The use of whole-wall HEPA filtration units with horizontal laminar flow in patient rooms reduced the number of Aspergillus organisms in the air to 0.009 colony-forming units/m3, which was significantly lower than in all other areas of the hospital (p less than or equal to 0.03). No cases of nosocomial Aspergillus infection developed in 39 bone marrow transplant recipients who resided in this environment throughout their transplantation period compared with 14 cases of nosocomial Aspergillus infection in 74 bone marrow transplant recipients who were housed elsewhere (p less than 0.001). Thus, although bone marrow transplant recipients had an order-of-magnitude greater risk of nosocomial Aspergillus infection than other immunocompromised hosts, this risk could be eliminated by using HEPA filters with horizontal laminar airflow.

Pseudoepidemic of aspergillosis after development of pulmonary infiltrates in a group of bone marrow transplant patients

During February and March 1985, seven patients in the pediatric bone marrow transplant unit (PBMTU) of a 350-bed cancer hospital developed pulmonary infiltrates. Five of the patients had Aspergillus spp. isolated from the respiratory tract, and two of these patients had histologic evidence of aspergillosis. Between 26 February and 22 April, Aspergillus spp. were isolated in a total of 70 cultures from 39 hospitalized patients. Of the 70 cultures, 14 (group 1) were from respiratory specimens of PBMTU patients with pulmonary infiltrates and were submitted to the laboratory intermittently over the 56-day period. However, of the other 56 Aspergillus-positive cultures (group 2), 41 (73%) were submitted on six days during this period (P less than 0.001, chi-square goodness of fit), including 8 blood cultures submitted on one day. When Aspergillus sp. was recovered from group 1 cultures early during this period, the isolates were stored in the culture-processing room. Aspergillus isolates were not handled in a biological safety cabinet, and blood cultures were done by using a system which requires opening of an evacuated bottle to room air. The presence of stored Aspergillus isolates was associated with a markedly elevated concentration of airborne fungi in the culture-processing room. After removal of the stored Aspergillus isolates from the culture-processing room, the concentration of airborne fungi returned to background level and there were no further Aspergillus-positive cultures. These findings suggested that group 2 cultures had been contaminated by stored Aspergillus isolates. No evidence for a common source of infection was found in the PBMTU patients with pulmonary infiltrates.

Pathogenetic and serological aspects of pulmonary aspergillosis

Af is an important pathogen of the bronchopulmonary system, and the clinical spectrum encompasses aspergilloma, CNPA, IPA, ABPA, bronchial asthma, and allergic alveolitis. Bronchial carriage may, however, not always be associated with pathological effects. The polymorphism of the aspergillus-related disorders seems mostly to depend upon the different responses of the hosts. This review considers the antigenic composition of Af and specific antibody responses in man in relation to the pathogenesis and diagnosis of the various forms of pulmonary aspergillosis. More than 200 macromolecular components have been listed for Af and more than 30 antigens found to react with human sera. Serum antibodies to Af are common in healthy subjects. Schønheyder and his associates (A-L) have shown that IgG, IgA and IgM antibodies in healthy subjects are directed towards antigens to which also patients with aspergillosis strongly react. With immunofluorescent staining these antigens were found to be associated with hyphal walls, and a MW 470,000 fraction from ruptured mycelium was most reactive in ELISA. The respiratory tract appears to be the major route for exposure since the humoral responses include IgA class antibodies, and sIgA antibodies are found in bronchial secretions. Moreover, IgG antibody levels to the MW 470,000 fraction correlate with occupational exposure and smoking habits. In patients with cystic fibrosis high IgG antibody levels to MW 470,000 and MW 25,000-50,000 antigen fractions were associated with the carriage of Af in the sputum. An individual patient's level of IgA antibodies to the MW 470,000 fraction was inversely related to the Af carrier rate, and this was also true for IgE dependent reactivity to Af antigens. These observations indicate that IgG antibodies to some antigens mirror the extent of antigenic exposure, whereas some IgA and IgE antibodies may play a protective role against bronchial colonization with Af. IgG antibody determinations by ELISA were found to provide a higher diagnostic efficacy in pulmonary aspergillosis than IgA antibody assays. With IgG antibodies there were statistically significant differences between patients and the controls and there was little overlap of ELISA values between the groups. The fractions of MW 250,000 with catalase activity and MW 25,000-50,000 with protease activity, were most suitable for serological diagnosis. A gel immunoelectrophoretic assay proved Af catalase to be a major diagnostic antigen in patients with aspergilloma or with an apical aspergillus lung infiltrate.(ABSTRACT TRUNCATED AT 400 WORDS)

Detection of galactomannan antigenemia by enzyme immunoassay in experimental invasive aspergillosis

A sensitive enzyme immunoassay (EIA) for galactomannan antigenemia that avoids the use of radioisotopes was devised. Three carbohydrate-rich antigenic fractions were purified from Aspergillus fumigatus 2085: a cold alkali extract (CA) from mycelium, an acetone-precipitated pyridine extract (APSK-66) from mycelium, and a methanol precipitate from culture filtrate. CA and APSK-66 were further purified by gel filtration and ion-exchange chromatography, respectively. An acid hydrolysate of CA contained only mannose and galactose, as determined by gas-liquid chromatography. Rabbit antisera were raised against conidia, mycelia, and cell walls of A. fumigatus. By indirect EIA, the best immunoglobulin G response (1/8,000) was obtained against CA in rabbits immunized intravenously with cell walls. Antigenemia was detected by indirect EIA inhibition in heat-dissociated sera of four immunosuppressed rabbits that were infected intravenously but was absent in two uninfected controls. The circulating antigen was resistant to pronase, was adsorbed onto concanavalin A, and had a molecular size of 50 to 100 kilodaltons.

Construction activity: an independent risk factor for invasive aspergillosis and zygomycosis in patients with hematologic malignancy

Between November 1982 and July 1984, five patients at a 110-bed pediatric hospital were diagnosed with invasive filamentous fungal infection; three had invasive aspergillosis (IA) and two had invasive zygomycosis (IZ). All five had underlying hematologic malignancy (HM). In a case-control study, these five HM patients (cases) were compared to 10 autopsied HM patients without evidence of aspergillosis or zygomycosis (controls). Cases and controls did not differ in underlying disease or in the degree of immunosuppression, as measured by duration of granulocytopenia and number of platelet transfusions. However, case-patients were more likely than controls to have been hospitalized during the construction of a hospital addition (p less than 0.02, Fisher's exact test [FET]). Four (80%) of five HM patients autopsied during the period of construction had IA or IZ compared with one (5%) of 21 autopsied before construction began (p = 0.001, FET). These findings suggest that, in a population of comparably immunosuppressed patients, construction activity may represent an independent risk factor for IA or IZ. Hospitals caring for such patients should take precautions which minimize exposure of these patients to construction or renovation activity.

Use of cephalosporins in the immunologically compromised patient

Infection is a major threat to patients with neutropenia, particularly those with haematological malignancies who are undergoing chemotherapy. Early use of an empirical antibiotic regimen with the broadest possible spectrum of activity is recommended until culture data can guide the choice. A standard combination in many centres is an amino-glycoside and a semisynthetic penicillin with antipseudomonal activity or a cephalosporin. However, no regimen can adequately cover all potential pathogens and in these patients, who are exposed to many toxic insults, the choice of antibiotics may significantly increase the incidence of side effects, particularly nephrotoxicity. There has, therefore, been considerable interest in simpler, less toxic (and less expensive) regimens and the concept of monotherapy has been explored. Although recent studies using ceftazidime alone have supported this as an effective approach, there remain several issues to resolve; and on a more cautionary note preliminary results from the latest EORTC study, which recruited more than 1200 patients, suggest that in Gram-negative bacteraemia, conventional combination therapy remains the treatment of choice in neutropenia. While monotherapy is attractive in an environment of low drug resistance when exposure to third generation cephalosporins is infrequent, this is rarely the case. In addition, the widespread use of tunnelled catheters for venous access had led to an increase in Gram-positive infections, and the more intensive immunosuppression to the emergence of fungal infections. Although these tend not to be rapidly fatal, their presence must be considered in designing treatment strategies. The influence of the host and treatment on the type of infection and the relative merits of the differing concepts in therapy are explored in detail in this article.

Significance of isolation of Aspergillus from the respiratory tract in diagnosis of invasive pulmonary aspergillosis. Results from a three-year prospective study

The isolation of Aspergillus species from respiratory secretions has been regarded as being of limited usefulness in the antemortem diagnosis of invasive pulmonary aspergillosis. One hundred and eight consecutive patients were evaluated in whom Aspergillus species were isolated from respiratory secretions. Invasive aspergillosis was not demonstrated in non-immunosuppressed patients or in patients with solid tumors in the absence of neutropenia. Lung tissue was examined in 17 patients with leukemia and/or neutropenia; all had invasive aspergillosis. Tissue examination was not performed in 20 neutropenic patients; of 17 not receiving antifungal therapy, 16 died. Multivariate statistical analysis showed that neutropenia and absence of cigarette smoking were significant predictors of invasive aspergillosis in patients with respiratory tract cultures yielding Aspergillus. All cases of invasive aspergillosis were associated with A. fumigatus or A. flavus. The isolation of A. fumigatus or A. flavus from the respiratory tract of a patient with leukemia and/or neutropenia is highly predictive of invasive infection. Empiric amphotericin B therapy, without the necessity for tissue diagnosis, should be considered in this patient subgroup.

Aspergillus sinusitis in cancer patients

Paranasal sinusitis occurred in 52 immunosuppressed cancer patients treated over 5 years at the University of Maryland Cancer Center. Twenty-one patients had aspergillus sinusitis; Aspergillus sp, including flavus and niger were directly recovered from sinus in 19 of the 21 infections. Two other patients with sinus involvement and positive nose cultures for Aspergillus flavus or fumigatus and microbiologically documented pulmonary aspergillosis were considered clinically, although not microbiologically, documented. Predisposing factors for aspergillus sinusitis during the 60 days prior to infection diagnosis were granulocyte count less than 500 microliter (mean duration, 42 days versus 14 days for sinusitis of other etiology; P less than 0.001), prolonged hospitalization (mean duration, 22 days versus 14 days for patients with nonfungal sinusitis; P less than 0.001), and prolonged antibiotic therapy (mean duration, 22 days versus 9 days; P less than 0.001). Treatment with amphotericin B was initially successful for 18 of 21 patients; however, 11 of 18 patients had infection recurrence that always developed at time of tumor exacerbation and reinstitution or intensification of chemotherapy. These findings suggest that aspergillus sinusitis in cancer patients is seen in association with prolonged neutropenia and antibiotic therapy, is amenable to therapy, but tends to recur with relapse of malignancy.

Possible risk of invasive pulmonary aspergillosis with marijuana use during chemotherapy for small cell lung cancer

Bacterial and fungal contaminants have been identified in marijuana samples and thus are a potential risk factor in the immunocompromised patient using it as an antiemetic. We describe the development of an invasive pulmonary aspergillosis in a patient using illicitly obtained marijuana as an antiemetic during combination antitumor therapy for small cell lung cancer. Although this patient had multiple risk factors implicated in the development of invasive pulmonary aspergillosis, the infectious potential of inhaled marijuana must be recognized. Further study of this potential health risk in needed.

Head and neck aspergillosis in patients undergoing bone marrow transplantation. Report of four cases and review of the literature

Aspergillus infection can be a major cause of morbidity in immunocompromised patients, especially when there is pulmonary involvement. Diagnosis of aspergillosis is often complicated by the varied clinical presentation and compromised medical status of such patients. Four cases of head and neck Aspergillus infections in bone marrow transplant patients are presented. Involvement predominantly was limited to the oral cavity and/or sinuses, and in one case, the ear. Two cases were successfully managed with a combined antibiotic and surgical approach, and one case with antibiotics only. The fourth case was managed with antibiotics and surgery, but fatal hemorrhage secondary to sinus involvement developed.

The surgical management of fungal pulmonary infections in children with acute myelogenous leukemia

Infections are the primary cause of complications and death in patients with acute myelogenous leukemia. Current aggressive treatment protocols have improved patient survival but produce extended periods of profound neutropenia during which the patients are particularly susceptible to opportunistic infections. Candida and Aspergillus species are the most common of the fungi causing invasive infections in these patients. In a group of 77 previously untreated children with acute myelogenous leukemia begun on treatment from March 1976 to June 1984, four patients developed localized fungal infections of the lung. These initially appeared as pulmonary infiltrates on chest roentgenograms during periods of severe neutropenia (three during remission induction and one after intensive consolidation therapy). Endobronchial cultures failed to identify the infectious organism in all cases. Computerized axial tomography best defined the cavitary nature of the lesions in 2 patients. All four patients underwent surgical resection, both to establish a diagnosis (three patients) and as part of therapy. There was no operative morbidity. The organisms involved were Aspergillus (2), Torulopsis (1), and Penicillium (1). Three patients were cured of their fungal infections. The fourth patient failed to enter remission and died of a cerebral fungal abscess that developed shortly after thoracotomy. We report these cases to encourage early surgical intervention in leukemics with a localized pulmonary process consistent with a fungal infection. Resection of the primary focus obviates the risk of life threatening pulmonary hemorrhage or dissemination of the fungus and allows for early reinstitution of chemotherapy which is vital to these patients' survival.

Aspergillosis of the nose and paranasal sinuses in neutropenic patients at an oncology center

Invasive aspergillosis of the nose and paranasal sinuses is one of the presentations of aspergillosis in granulocytopenic patients with neoplastic disorders. It is most prevalent among patients with leukemia and granulocytopenia and is associated with a high mortality rate. We report five cases of invasive aspergillosis of the nose and paranasal sinuses in profoundly neutropenic patients treated with broad spectrum antibiotics. Both Aspergillus fumigatus and Aspergillus flavus were cultured and identified in this entity. Awareness of this disease and early diagnosis made by culture and histologic examinations of biopsy material are essential. Treatment consisting of amphotericin B therapy and surgical debridement can be effective in eradicating this form of aspergillosis.

An outbreak of invasive aspergillosis among allogeneic bone marrow transplants: a case-control study

Between April 1982 and March 1983, 10 of 26 (38.4%) allogeneic bone marrow transplant recipients housed on a newly opened bone marrow transplant unit developed invasive aspergillosis. By contrast, between September 1977 and March 1982, only 3 of 46 (6%) transplant recipients developed invasive aspergillosis. A case-control study to identify host factors related to Aspergillus infection found that aspergillosis was more common in patients with chronic myelogenous leukemia and aplastic anemia, older patients, patients having cytomegalovirus disease, patients who experienced prolonged granulocytopenia, patients conditioned with ara-C (100-200 mg/day), and patients who received longer duration of antimicrobial therapy. A series of logistic regression analyses revealed that underlying disease was the single best predictor of Aspergillus infection. This study demonstrates that underlying disease is an important risk factor for aspergillosis and that special measures may be warranted when transplanting certain patients.

Itraconazole, a new triazole that is orally active in aspergillosis

Itraconazole is a new orally active triazole derivative with broad-spectrum antifungal activity. This drug is effective in experimental aspergillosis and possesses in vitro activity against various species and strains of Aspergillus. Morphological destruction of inoculated hyphae and complete inhibition of hyphal outgrowth in culture is obtained from 0.07 micrograms ml-1 (10(-7)M) onward. These properties make itraconazole a likely candidate for clinical evaluation in disseminated aspergillosis.

Role of fiberoptic bronchoscopy in the diagnosis of invasive pulmonary aspergillosis in patients with acute leukemia

The utility and safety of fiberoptic bronchoscopy in the diagnosis of invasive pulmonary aspergillosis in patients with acute leukemia have not been examined. The results of 21 bronchoscopic procedures in 19 patients with invasive pulmonary aspergillosis and acute leukemia were reviewed. Analysis was confined to the 16 patients who had histopathologically documented infection on biopsy or at autopsy. Fiberoptic bronchoscopy established or suggested the diagnosis of invasive pulmonary aspergillosis in eight of 16 (50 percent) patients. Transbronchial or bronchial biopsy added only one diagnosis to those obtained by bronchial washing and brushing. Although fiberoptic bronchoscopy was a safe and well-tolerated procedure in our patients with invasive pulmonary aspergillosis and acute leukemia, its success rate was only 50 percent overall, and it appeared to be even less successful when performed early in the course of the disease. Fiberoptic bronchoscopy is a useful first procedure for the evaluation of patients with acute leukemia and possible invasive pulmonary aspergillosis, but a negative result does not exclude aspergillosis. Further diagnostic procedures, including repeated bronchoscopy, or institution of empiric antifungal therapy may be warranted if the clinical suspicion of invasive pulmonary aspergillosis is high.

Extrinsic risk factors for pneumonia in the patient at high risk of infection

Most nosocomial pathogens cause pneumonia through the following sequence: transit to the patient on the hands of medical personnel or perhaps in food, proliferation in the nasopharynx, and subsequent pulmonary aspiration. There are three exceptional pathogens, each of particular concern as a cause of pneumonia in the immunocompromised patient, which follow atypical routes. Important recent advances in understanding these routes permit more rational preventive measures. This report examines the evidentiary basis for the following pathophysiolgic propositions about these three pathogens: Aspergillus, Pneumocystis carinii, and Legionella. Aspergillus spores are almost ubiquitous. Spore generation, except in very unusual circumstances, takes place outside the hospital. Most spores enter the hospital borne in air by infiltration or because of incomplete filtration. Air filtration systems of moderate efficiency remove Aspergillus spores. Nosocomial pulmonary and disseminated aspergillosis arises from inhalation of airborne spores. A nasopharygeal colonization intermediate step before pulmonary disease has not yet been solidly established. It is now firmly established that airborne Pneumocystic carinii transmission occurs between animals. Airborne acquisition probably occurs early in human life. However, in-hospital, person-to-person transmission has yet to be convincingly demonstrated. Most or all cases of pneumocystosis in adults are due to reactivation of endogenous pulmonary organisms. Intensive diagnostic efforts reveal that Legionella is a common cause of community-acquired and nosocomial pneumonia in hospitals where it had not previously been recognized. However, there are at least a few hospitals where it is an uncommon source of pneumonia. Several hospitals have demonstrated a temporal association between the presence of Legionella in hot water systems and nosocomial cases of Legionella pneumonia. The mechanism or mechanisms of transmission to the patient remain to be delineated. It is also not determined if all hospital hot water systems should be maintained Legionella free.

Management of the immunocompromised host

This article deals with the management of the immunocompromised host. Mechanisms of immunocompromise include alterations in skin and mucosal barriers, normal oral and intestinal flora, splenic function, and number or function of T cells, B cells, granulocytes, and monocytes. Discussed in this article are ways for maintaining those defenses not altered by the primary disease, minimizing the environmental risks to the patient, anticipating potential infections in order to institute appropriate prophylactic measures, and diagnosing and aggressively treating infections as they occur.

Can antibacterial therapy be discontinued in persistently febrile granulocytopenic cancer patients?

It has been suggested that empiric broad-spectrum antibiotics, instituted for fever in the presence of granulocytopenia, should continue to be administered, even when infection is not demonstrable, to those patients who remain persistently febrile and granulocytopenic. Therefore, the consequences of discontinuing antibiotics when the presence of infection is doubted in this setting were evaluated. In 16 (3.7 percent) of 429 episodes of fever and granulocytopenia for which empiric antibiotic therapy was instituted, after approximately four days, persistence of both fever and granulocytopenia was found, and yet infection was prospectively classified at that time as "doubtful." The initial empiric antibiotic regimen was therefore discontinued after a mean of 4.8 (median 5.0) days. Discontinuation of antibiotics proved appropriate for half of the patients; eight patients received no systemic therapeutic antibiotics with no evidence of infection during a period of at least two weeks. The other eight patients had antibacterial antibiotics reinstituted within a mean of 2.4 days; six infections were subsequently demonstrable. Six of these eight patients also required or were believed to require antifungal therapy with intravenous amphotericin B for presumed fungal infections. Patients with relapsed leukemia or lymphoma and those with a likelihood of continued profound granulocytopenia (counts below 100/microliters) or both were the ones who tended to require reinstitution of antibiotics. Discontinuation of antibiotics when infection was considered doubtful despite persistence of both fever and granulocytopenia was, therefore, successful in eight of 16 patients. Reinstitution of antibiotics was required in the eight remaining patients. No definite rule appears to be applicable to all patients.

Multivariate analysis of factors associated with invasive fungal disease during remission induction therapy for acute myelogenous leukemia

The clinical courses of 54 consecutive adult patients with acute myelogenous leukemia (AML) who underwent 67 courses of intensive remission induction therapy were analyzed to assess factors associated with development of serious fungal and bacterial infections. Fever developed in 65 of 67 remission induction attempts and was due to bacterial, bacterial-fungal, and fungal etiologies in 49%, 14%, and 9% of cases, respectively. No etiology of fever was found in 28% of cases. Bacteremia occurred in 54% of remission induction attempts. Invasive fungal disease (IFD) occurred in 22% of cases with an overall mortality of 60%, including 45% of the patients who died during treatment. Using multivariate logistic regression analysis, a mathematical model was constructed which correlated with the risk of IFD. Major factors associated with patients who ultimately develop IFD included the duration of chemotherapy, the number of sites colonized with fungi and the number of fungal species isolated on certain surveillance cultures, particularly Aspergillus species. These studies define characteristics of patients at high risk for development of IFD for whom early initiation of empiric antifungal therapy is strongly recommended.

Aspergillosis in 25 renal transplant patients. Epidemiology, clinical presentation, diagnosis, and management

In immunocompromised renal transplant patients, aspergillosis can be a life-threatening opportunistic infection. During an 8-year period, 25 renal transplant recipients at the University of Minnesota Hospitals developed unequivocal invasive aspergillosis that occurred in epidemic-like patterns in immunocompromised patients throughout the hospital. The premortem diagnosis was made in only 14 of the 25 patients. Seventeen patients died, and three of the eight survivors lost their allografts. The prognosis was dependent upon the clinical pattern of illness: three clinical patterns emerged: (1) cavitary lung disease, (2) diffuse pulmonary disease, and (3) central nervous system disease. All patients in the latter two categories died. The best results were with those patients treated with both amphotericin B and excision of cavitary lung lesions. All three patients treated in this manner survived with functioning grafts. Traditionally, sputum cultures have been thought to be unreliable because Aspergillus is a common colonizer of the upper respiratory tract and a contaminant in laboratories. In this study, false positive sputum cultures were common. A positive sputum culture can be helpful, however, all patients with two positive sputum cultures proved to have invasive aspergillosis. In addition, 86% of patients with positive sputum cultures who were clinically ill proved to have invasive infection. Bronchoscopy is a useful technique to follow up a positive sputum culture or investigate negative sputum cultures with typical clinical patterns. Routine bronchoscopy, unfortunately, also yields a high incidence of false positive cultures. Since the use of covered brush bronchoscopy technique, however, no false positive transbronchial cultures have been found. Transbronchial biopsy is a useful adjunct and is proof of the presence of invasive disease when the results are positive. However, false negative results are also found. Overall, the highest diagnostic yield is obtained both with transbronchial lung biopsy and covered brush bronchoscopy culture. All eight patients with both these procedures were correctly identified as having invasive pulmonary aspergillosis.

Prevention of infection among patients with cancer

Recognition of the alterations of host defense allows a rational approach to preventing associated infections. One of the most effective strategies for preventing infection in the granulocytopenic patient is the combined use of oral non-absorbable antibiotics, laminar air-flow room reverse isolation with strict housekeeping techniques, low microbial diet, sterile water, and topical antiseptics and antibiotics. The prohibitive cost, however, warrants that this system be restricted to research settings. The suppression of aerobic Gram-negative bacilli and fungi and the preservation of colonization resistance with such combinations as trimethoprim-sulfamethoxazole and nystatin show promise in preventing infection in the granulocytopenic patient. Prevention of infection in neutropenic patients also requires attention to simpler but very effective measures such as immunizations, antimicrobial prophylaxis against intracellular and nonbacterial pathogens in high-risk patients, limiting invasive diagnostic and monitoring procedures, hand-washing by all personnel between visiting patients, oral hygiene, low microbial diets, axillary and perianal swabbing, and care with venipunctures and marrow aspirates. Finally, while the recommendations for prevention of infection are likely to continue to change with resulting improvement in patient care [92, 93], a tabulation summarizing current practices can be established based on our current knowledge (Table 1).

Invasive aspergillosis of paranasal tissues in children with malignancies

Paranasal aspergillosis was encountered in five children with relapsed malignancies. All had received broad-spectrum antibiotics within two weeks of development of aspergillosis, and all had absolute granulocyte counts less than 200/mm3 for at least three weeks. None had received prior antifungal therapy. There was an average delay of eight days before the correct diagnosis was established by either biopsy or culture. These data emphasize the need to obtain surveillance cultures of the upper respiratory tract passages in severely neutropenic patients receiving prolonged antibiotic therapy, and raise a question concerning prophylactic use of antifungal therapy in this group.

A prospective study of infectious diseases following bone marrow transplantation: emergence of Aspergillus and Cytomegalovirus as the major causes of mortality

We performed a prospective study of infections following bone marrow transplantation in 50 patients treated for aplastic anemia or hematologic malignancy. Early, continuous prophylaxis with trimethoprim/sulfamethoxazole and oral nystatin, and empiric intravenous antimicrobial therapy during febrile granulocytopenic episodes were standard treatment for all patients. The use of trimethoprim/sulfamethoxazole did not appear to adversely affect donor marrow engraftment. Serious gram-negative bacillary and systemic Candida infections were uncommon. Although gram-positive bacterial infections were frequent, they were rarely associated with mortality. Aspergillosis emerged as the single most important infection, contributing to the death of nine patients. Cytomegalovirus diseases developed in 13 patients, seven of whom died. Patient age and chronic myelogenous leukemia were risk factors for the development of fatal infections. This study demonstrates that although certain serious infections can be controlled, there is a critical need for effective measures to prevent and treat aspergillosis and cytomegalovirus disease in these seriously compromised hosts.

Aspergillus epiglottitis

A 21-year-old woman with acute lymphocytic leukemia developed clinical and radiographic signs of epiglottitis. Premortem and postmortem histologic studies showed invasive aspergillosis; Aspergillus flavus was grown in culture. The necrotizing nature of this infection is explained by the predilection of Aspergillus sp. for invasion of blood vessels. The usual causative agents of epiglottitis are bacteria; the association with fungal infection has not been previously described.

Clinical value of empirical amphotericin B in patients with acute myelogenous leukemia

From August 1977 to October 1978, 23 patients with acute myelogenous leukemia (AML) received induction therapy at Vanderbilt University Hospital. Six patients died of documented fungal infection, predominantly aspergillus pneumonia; the complete remission rate was only 40%. Based on this experience we began using amphotericin B empirically in any AML patient remaining febrile or having recurrent fever after a week of broad spectrum antibiotics. Of 22 patients treated from October 1978 to August 1980, none died of fungal infection during induction therapy; the remission rate increased significantly to 77%. Chemotherapy and supportive care were otherwise unchanged during this period. While the first group was older, the improvement in remission rate was also seen in patients younger than 60 years of age. Since fungal infection may be difficult to document, this study suggests that empirical amphotericin B is reasonable therapy in leukemic patients remaining febrile or having a recurrent fever following a week of broad spectrum antibiotics, if the institution has a high incidence of fungal infections.