Pulmonary Infections In Immunocompromised Patients Research Articles

The application value of metagenomic next-generation sequencing technology in diagnosis and treatment of pulmonary infection in immunocompromised patients

Objective: To evaluate the application value of metagenomic next-generation sequencing (mNGS) in the diagnosis and treatment of pulmonary infection in immunocompromised patients. Methods: A total of 78 patients with immunocompromised pulmonary infection [55 males and 23 females, aged (50.3±16.9) years] and 61 patients with non-immunocompromised pulmonary infection [42 males and 19 females, aged (63.6±15.9) years] in the Intensive Care Unit of the First Medical Center of College of the Pulmonary & Critical Care Medicine, Chinese PLA General Hospital from November 2018 to May 2022 were retrospectively selected. Patients in both groups received bronchoalveolar lavage fluid (BALF) mNGS and conventional microbiological tests (CMTs) while clinically diagnosed with pulmonary infection. The diagnostic positive rate, pathogen detection rate and clinical coincidence rate of the two methods were compared. At the same time, the difference of adjustment rate of anti-infective treatment strategy based on the results of mNGS detection was compared between the two groups. Results: The positive rates of mNGS in patients with pulmonary infection were 94.9% (74/78) and 82.0% (50/61) in the immunocompromised group and the non-immunocompromised group, respectively. The positive rates of CMTs in patients with pulmonary infection were 64.1% (50/78) and 75.4% (46/61) in the immunocompromised group and the non-immunocompromised group, respectively. The positive rates of mNGS and CMTs in patients with pulmonary infection in immunocompromised group showed a statistically significant difference (P<0.001). The detection rates of mNGS in the immunocompromised group for pneumocystis jirovecii and cytomegalovirus were 41.0% (32/78) and 37.2% (29/78), respectively, and the detection rates of Klebsiella pneumoniae, chlamydia psittaci and Legionella pneumophila were 16.4% (10/61), 9.8% (6/61) and 8.2% (5/61) in the non-immunocompromised patients, respectively, which were higher than those of CMTs [1.3% (1/78), 7.7% (6/78), 4.9% (3/61), 0 and 0] (all P<0.05). In the immunocompromised group, the clinical coincidence rates of mNGS and CMTs and were 89.7% (70/78) and 43.6% (34/78), respectively, with a statistically significant difference (P<0.001). In the non-immunocompromised group, the clinical coincidence rates of mNGS and CMTs were 83.6% (51/61) and 62.3% (38/61), with a statistically significant difference (P=0.008). In the immunocompromised group, according to the results of the etiology of mNGS, the adjustment rate of anti-infection treatment strategy was 87.2% (68/78), while in the non-immunocompromised group, the adjustment rate of anti-infective treatment strategy was 60.7% (37/61), with a statistically significant difference (P<0.001). Conclusion: In patients with immunocompromised pulmonary infection, mNGS has more advantages than CMTs in diagnostic positive rate, diagnosis rate of mixed infection, pathogen detection rate and guidance of anti-infection treatment strategy adjustment, which is worthy of clinical promotion and application.

Nadir bir etken: Rhodococcus equi, immünkompetan hastalarda yumuşak doku enfeksiyonlarına ilişkin bir vaka sunumu ve literatür incelemesi

Rhodococcus equi (R. equi) is a microorganism that was first identified in horses. Afterward, it was found to cause opportunistic infections in immunosuppressed patients. It causes especially pulmonary infections in immunocompromised patients while it rarely causes diseases such as septic arthritis and soft tissue infections. It is important to question epidemiological risk factors for the diagnosis of the disease. Also, the clinician-microbiologist relationship is important in the laboratory diagnosis of the microorganism because it is possible to be missed as part of normal flora or contaminant or to be confused with microorganisms with similar phenotypic features (Nocardia species or rapidly growing mycobacteria). Rarely, it has been reported in immunocompetent patients, as in our case. MEDLINE, SCOPUS, Google Scholar, and Cochrane searches were performed using the keywords Rhodococcus equi and Corynebacterium equi from 1945 to July 2021. A total of 582 articles were determined. Articles containing these keywords were then scanned for the words “humans”, “soft tissue infections”, and “cellulite” and a total of 42 articles were listed in the end. A total of 14 case reports of soft tissue infection/cellulitis in immunocompetent patients related to R. equi were detected in the literature. In our case, there was a soft tissue infection and R. equi was detected in the abscess culture. Obtaining culture and determining the factor is very important in the treatment of infections. In this report, soft tissue infections caused by R. equi in immunocompetent patients are reviewed.

TO STUDY THE CLINICAL, RADIOLOGICAL AND MICROBIAL PROFILE OF PULMONARY INFECTION IN IMMUNOCOMPROMISED PATIENTS

BACKGROUND The lung is one of the most frequently involved organs in complications of immunocompromised host. Among these, pulmonary infection is the most common complication. The chest radiograph is initial diagnostic tool for detection of suspected pulmonary infection in immunocompromised. However, chest radiograph ndings are nonspecic in determining pathogens. The early use of Computed Tomography (CT) is helpful in detecting pulmonary lesions which may not be evident on routine chest radiographs. But there is overlap of CT nding in different infections. This study is therefore, designed to document the clinical, radiological &amp; microbial prole of pulmonary infection in immunocompromised patients. AIM To study the clinical, radiological and microbial prole of pulmonary infection in immunocompromised patients, and to study diagnostic yield of sputum examination, induced Sputum examination &amp; bronchoscopic BAL examination. METHODS The present prospective descriptive observational study was conducted in the Department of Chest Medicine at King Edward Memorial Hospital, Pune. It included immunocompromised patients with lower respiratory tract infection symptoms. A total number of 70 indoor &amp; OPD patient with urban &amp; rural background were included in the study. Among them 45 patients were HIV reactive group and 25 patients were having Non-HIV immunocompromised condition. All of them had pulmonary infection. The study was conducted over a period of 15 months. RESULTS Incidence of pulmonary infection was higher in age 31-40 years (28.58%). There were 51 males and 19 females. Opportunistic infections were more common in males as compared to females. Majority of immunocompromised patients were HIV reactive (64.3%) followed by of Malignancy (15.7%). Focal non homogenous opacity (37.5%) was most common radiological nding followed by consolidation with air brochogram (25%). Pulmonary Tuberculosis (40.5%) was most common opportunistic infection in immunocompromised patients followed by bacterial (30.38 %) and fungal infections (17.72%). Sputum (40.98), induced sputum examination (19.29), and Bronchoscopy with BAL (91.42%) had good diagnostic yield in diagnosis of pulmonary infection in immunocompromised patients. CONCLUSION Induced sputum had less diagnostic yield in immunocompromised patients and also it is time consuming.Early bronchoscopy with BAL remains crucial to establish the diagnosis in immunocompromised patients with pulmonary infection when the cause is infectious in nature.

Detection of glucosamine as a marker for Aspergillus niger: a potential screening method for fungal infections

Several species of fungus from the genus Aspergillus are implicated in pulmonary infections in immunocompromised patients. Broad screening methods for fungal infections are desirable, as cultures require a considerable amount of time to provide results. Herein, we developed degradation and detection methods to produce and detect D-glucosamine (GlcN) from Aspergillus niger, a species of filamentous fungus. Ultimately, these techniques hold the potential to contribute to the diagnosis of pulmonary fungal infections in immunocompromised patients. In the following studies, we produced GlcN from fungal-derived chitin to serve as a marker for Aspergillus niger. To accomplish this, A. niger cells were lysed and subjected to a hydrochloric acid degradation protocol. Products were isolated, reconstituted in aqueous solutions, and analyzed using hydrophilic interaction liquid chromatography (HILIC) in tandem with electrospray ionization time-of-flight mass spectrometry. Our results indicated that GlcN was produced from A. niger. To validate these results, products obtained via fungal degradation were compared to products obtained from the degradation of two chitin polymers. The observed retention times and mass spectral extractions provided a two-step validation confirming that GlcN was produced from fungal-derived chitin. Our studies qualitatively illustrate that GlcN can be produced from A. niger; applying these methods to a more diverse range of fungi offers the potential to render a broad screening method for fungal detection pertinent to diagnosis of fungal infections.Graphical abstract

Peculiarities of bacterial agents of pneumonia in HIV-infected patients. Preventive measures for pulmonary infections in immunocompromised patients (literature review)

The problem of HIV infection in Russia remains topical, despite the active prevention and use of antiretroviral therapy. The main causes of hospitalization and lethal outcome among HIV patients are respiratory diseases, community-acquired pneumonia in particular. This article analyzes the literature data on causative agents of pneumonia in HIV-positive patients, the possibility to vaccinate such patients and its effectiveness.

Diagnostic accuracy of magnetic resonance imaging in the evaluation of pulmonary infections in immunocompromised patients.

PurposeTo evaluate the accuracy of magnetic resonance imaging (MRI) for diagnosing pulmonary infections in immunocompromised adults.Material and methodsComputed tomography (CT) and MRI chest were performed in 35 immuno-compromised patients suspected of pulmonary infection. The MRI sequences that were performed included axial and coronal T2 half-Fourier acquisition single-shot turbo spin-echo (HASTE), spectrally attenuated inversion recovery (SPAIR), true fast imaging with steady-state free precession (TRUFI), and three-dimensional fast low angle shot (3D FLASH) using breath-hold and respiratory triggered BLADE (proprietary name for periodically rotated overlapping parallel lines with enhanced reconstruction). The presence of nodules, consolidations, and ground-glass opacities was evaluated. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated for MRI using CT scan as a reference standard.ResultsThe sensitivity of MRI in nodule detection was 50% overall and 75% for nodules measuring more than 5 mm. Consolidation was detected with 100% sensitivity. Sensitivity and PPV for the detection of ground-glass opacities (GGOs) were 77.7% and 53.8%, respectively. T2 HASTE axial had the fewest image artefacts. Respiratory triggered MR pulse sequence did not add any significant diagnostic information as compared to the non-respiratory triggered MR pulse sequences.ConclusionsSensitivity for detecting small nodules and GGOs on MR is poor; CT scan remains the imaging modality of choice for the evaluation of pulmonary infections in immunocompromised patients. However, MRI can be used in the follow-up imaging of these patients.

Differential diagnosis of pulmonary infections in immunocompromised patients using high-resolution computed tomography.

The aims of this study were to compare the high-resolution computed tomography (HRCT) findings of pulmonary infections in immunocompromised patients and to assess the usefulness of HRCT in the differential diagnosis of these infections. A total of 345 immunocompromised patients with pulmonary infections were included in this study. The diagnoses of the patients consisted of bacterial pneumonia (123 cases), pneumocystis pneumonia (PCP) (105 cases), fungal pneumonia (80 cases), tuberculosis (15 cases), cytomegalovirus pneumonia (11 cases), and septic embolism (11 cases). Two chest radiologists retrospectively evaluated the computed tomography (CT) images, which consisted of 22 findings including ground-glass attenuation, consolidation, nodules, and thickening of the bronchial wall and interlobular septum. Associations between the CT criteria and infections were investigated using χ2 test; multiple logistic regression analyses were conducted to identify the significant indicator for each infection. The area under the curve (AUC) of each model was calculated. Bronchial wall thickening was a significant indicator for bacterial pneumonia (p = 0.002; odds ratio [OR], 2.341; 95% confidence interval [CI], 1.378-3.978). The presence of a mosaic pattern and the absence of nodules were significant indicators for PCP (p < 0.001; OR, 9.808; 95% CI, 4.883-13.699, and p < 0.001; OR, 6.834; 95% CI, 3.438-13.587, respectively). The presence of nodules was a significant indicator for fungal infection (p = 0.005; OR, 2.531; 95% CI, 1.326-4.828). The AUC for PCP was the highest (0.904). HRCT findings are potentially useful for the differential diagnosis of some pulmonary infections in immunocompromised patients. • Differential diagnosis of pulmonary infections in immunocompromised patients could be established with the help of high-resolution computed tomography. • Bronchial wall thickening was a significant indicator for bacterial pneumonia. • The presence of a mosaic pattern and the absence of nodules were significant indicators for pneumocystis pneumonia.

Identification and in Vitro Susceptibility Pattern of Fungal Pathogens in Immunocomprimised Patients with Pulmonary Fungal Infections

AbstractBackground: The frequency of fungal infections of the lung has increased particularly in immunocompromised pa-tients. Early diagnosis and treatment is important to start antifungal therapy and to avoid unnecessary use of toxic antifungal agents. This study aimed to identify the common fungal species causing pulmonary infection in immunocom-promised patients and their in vitro antifungal sensitivity pattern in Assiut University Hospitals (AUH).Subjects and Methods: This was a hospital based descrip-tive study conducted on 135 patients admitted at different Intensive Care Units (ICUs) and Oncology Department at Assiut University Hospitals (AUH). Collected respiratory specimens were subjected to direct microscopic examination and inoculation on Sabouraud Dextrose Agar (SDA). Identi-fication of isolated yeasts was done using phenotypic methods including chromogenic media (Brilliance Candida agar and CHROMagar Candida differential media), germ tube test, cornmeal agar and API candida while mould isolates identifi-cation was mainly dependent on macroscopic and microscopic features. Some isolates had confirmed using rRNA gene sequencing. In vitro antifungal susceptibility testing was done using disc diffusion method.Results: In this study 80/135 (59.3%) of collected samples were positive for fungal infection. The most common fungal pathogens isolated were Candida and Aspergillus species. In vitro sensitivity test showed that the yeast isolates had the highest sensitivity to Nystatin (90.9%) followed by Ampho-tericin B (80.3%) while for mould isolates, the highest sensi-tivity was to Voriconazole (71.4%) followed by Amphotericin B (57.1%).Conclusion: Pulmonary fungal infection appears to be an important problem in immunocomprimised patients with Candida albicans was the most commonly isolated yeast from various clinical specimens; also the increase in the resistance especially to azoles is a major concern.

Pulmonary Infections in Immunocompromised Hosts: Clinical.

Pulmonary infections in immunocompromised patients remain a significant contributor to mortality, morbidity, and health care-associated costs in such a vulnerable patient population. Their epidemiology is changing, set forth by new trends in immunosuppressive regimens and also prophylaxis. The host characteristics, presenting clinical symptomatology, along with radiographic patterns, have also evolved. The microbiology diagnostics are now enriched with nonculture methods for better identification of the causative pathogens. Chest imaging remains the cornerstone of the initial workup. Our article will examine the new trends in epidemiology, clinical findings, and diagnostics for immunocompromised patients with pulmonary infections (transplant recipients, neutropenic hosts, HIV-infected patients, and patients with autoimmune conditions). We will also review the differential diagnosis that most of the times includes malignancies and drug or radiation-related toxicities.

Colonization of Pneumocystis jirovecii in Patients who Received and not Received Corticosteroids Admitted to the Intensive Care Unit: Airborne Transmission Approach

Pneumocystis pneumonia (PCP) is responsible for pulmonary infection in immunocompromised patients. The current study aimed at investigating the frequency of Pneumocystis colonization in patients hospitalized in the intensive care unit (ICU) and evaluating the relationship between PCP and Pneumocystis colonization. The current cross sectional study was conducted on bronchoalveolar lavage (BAL) fluids of 100patients collected from surgery and neurosurgery ICUs with different underlying corticosteroid therapy conditions. Patients were divided into 2 groups (patients receiving and not receiving corticosteroids). Direct examination on BAL fluids was performed by the Gomori methenamine silver and Giemsa staining techniques. Additionally, 2 filtered air samples of the 2 above mentioned units were collected. A nested-PCR targeted mtLSUrRNA gene and sequencing were used to identify Pneumocystis spp. In direct microscopy, 31 out of 100 hospitalized patients (31%) showed positive results. Twenty-three (46%) of smear positive patients were from the group of patients receiving corticosteroid, the other 8(16%) were from the group of patients not receiving corticosteroids (P= 0.001). Pneumocystis jirovecii DNA was detected in 77 out of 100 BAL samples by nested-PCR (77%) in which 40 (52%) and 37 (48%) samples were obtained from the patients receiving and not receiving corticosteroids, respectively. Pneumocystis genome was observed in 1 of the 2 filtered air samples. A significant number of patients receiving corticosteroids were also colonized by P. jirovecii that may be predisposed to PCP or be transmitted to susceptible patients. A significant relationship was observed between the mean hospital stay and detection rate.

Phanerochaete sordida as a cause of pulmonary nodule in an immunocompromised patient: a case report

BackgroundPhanerochaete sordida is a species of wood rotting fungus, which can degrade lignin, cellulose and hemicellulose contained in wood and other hard-to-biodegrade organic substances. However, to date, there have been no other reports demonstrating that P. sordida can infect humans.Case presentationA 66-year-old Japanese man presented for a mass increasing in size on his left thigh. He had been suffering from rheumatoid arthritis for 18 years and chronic obstructive pulmonary disease for 20 years, for which he was being treated with 5 mg/day prednisolone and 8 mg/week methotrexate. The mass resection was performed two months later, and was diagnosed as malignant fibrous histiocytosis. However, a computed tomography examination for tumor recurrence after surgery showed a newly emergent pulmonary nodule. We therefore decided to resect the nodule by thoracoscopic procedure. Histopathological examination of the excised specimen showed that the lesion was a granuloma, with necrotic tissue and clumping of Aspergillus-like hyphae. Therefore, the nodule was diagnosed as a fungal infection and tissue specimens were cultured microbiologically. However, fungal growth was not observed. We consequently performed genetic analysis using a broad-range polymerase chain reaction. The 28S rRNA sequence demonstrated 100% homology with P. sordida using the NCBI BLAST program against the GenBank DNA databases.ConclusionsUsing broad-range polymerase chain reaction, we identified P. sordida as the causative agent of a pulmonary nodule. These findings indicate that P. sordida may be an additional opportunistic causative organism of pulmonary infection in immunocompromised patients.

Pulmonary infections in immunocompromised patients: the role of image-guided fine needle aspiration cytology.

To evaluate the role of fine needle aspiration cytology (FNAC) in the diagnosis of pulmonary infections in immunocompromised patients and to identify the imaging pattern of infections on computed tomography (CT). This was a retrospective study of 42 immunocompromised patients who underwent FNAC under image guidance owing to a clinical pulmonary infection. Each patient was evaluated for an underlying immunocompromised condition, cytological diagnosis, CT findings and complications. The most common predisposing condition was diabetes mellitus (n = 11), renal transplant status (n = 11) followed by connective tissue disorders (n = 6) and malignancy (n = 5). There were four patients with renal disease and three had a human immunodeficiency virus (HIV) infection. The most common cytological diagnosis was mucormycosis (n = 13) followed by nocardiosis (n = 8) and necrotising inflammation (n = 7), tuberculosis (n = 6), cryptococcosis (n = 2), aspergillosis(n = 2), histoplasmosis(n = 1) and atypical mycobacterial infection (n = 1). Mucormycosis presented as a pulmonary nodule (n = 7), mass lesion (n = 5) or consolidation (n = 4). The patients with nocardiosis had lung nodules with associated consolidation and cavitation. None of the patients had any major complication. FNA is a relatively reliable, safe and quick method of diagnosing pulmonary infection in immunocompromised patients. Cytomorphological features, when aided by special stains, can accurately detect the specific infection which is potentially treatable. Specific infections may be suggested based on specific imaging patterns.

Development of real-time polymerase chain reaction assay for specific detection of Tsukamurella by targeting the 16S rRNA gene

Recently, members of the genus Tsukamurella have been implicated as important etiologic pathogens contributing to bloodstream and pulmonary infections in immunocompromised patients. Tsukamurella species share many features with other mycolic acid–containing genera of the order Actinomycetales and might therefore be misidentified as belonging to one of these genera. We developed a TaqMan-based real-time polymerase chain reaction assay for the rapid and specific detection of infections due to Tsukamurella species. The assay amplifies and detects a 157-bp segment of the 16S rRNA gene of Tsukamurella. The specificity of the assay was confirmed using a panel of DNAs from 12 Tsukamurella strains and 11 strains belonging to 8 phylogenetic closely related genera. The sensitive and specific nature of the assay provides a valuable tool for the early and precise diagnosis of Tsukamurella infections in clinical diagnostic laboratories.

P.022 Human cytomegalovirus (HCMV) UL40 variability in renal transplant recipients

Bronchoalveolar lavage (BAL) is a useful tool in the diagnosis of pulmonary infections in immunocompromised patients. We aimed to compare the spectrum of infectious pulmonary complications diagnosed using BAL in a large consecutive cohort of immunocompromised patients.The diagnostic yield of 1066 BAL specimens was analyzed in 4 different groups of immunocompromised patients (HIV; solid organ transplants; high-dose chemotherapy and/or stem cell transplants; other immunosuppressive therapy) suffering from fever, respiratory symptoms and/or infiltrates on chest X-ray. Specimens were analyzed for bacteria, mycobacteria, fungi, Pneumocystis jiroveci, cytomegalovirus (CMV) and other viruses. Two time periods were compared (1992–1996; 1997–2003).The overall diagnostic yield of BAL was 34% for bacteria, 22% for CMV, 15% for P. jiroveci, 6% for other viruses, 6% for mycobacteria and 2% for aspergillus. There were significant changes in the pattern of opportunistic infections between the 2 time periods. Mycobacterial infections decreased considerably in the HIV group (17.9 vs. 8.5%, P=0.02), while the incidence of P. jiroveci decreased mainly in the transplant group (32.6 vs. 7.9%, P<0.00001).This study demonstrates a changed pattern of pulmonary infections in immunocompromised patients diagnosed by BAL. The overall diagnostic yield of BAL remains high in immunocompromised patients with respiratory symptoms.

Pulmonary infections diagnosed by BAL: A 12-year experience in 1066 immunocompromised patients

Bronchoalveolar lavage (BAL) is a useful tool in the diagnosis of pulmonary infections in immunocompromised patients. We aimed to compare the spectrum of infectious pulmonary complications diagnosed using BAL in a large consecutive cohort of immunocompromised patients. The diagnostic yield of 1066 BAL specimens was analyzed in 4 different groups of immunocompromised patients (HIV; solid organ transplants; high-dose chemotherapy and/or stem cell transplants; other immunosuppressive therapy) suffering from fever, respiratory symptoms and/or infiltrates on chest X-ray. Specimens were analyzed for bacteria, mycobacteria, fungi, Pneumocystis jiroveci, cytomegalovirus (CMV) and other viruses. Two time periods were compared (1992-1996; 1997-2003). The overall diagnostic yield of BAL was 34% for bacteria, 22% for CMV, 15% for P. jiroveci, 6% for other viruses, 6% for mycobacteria and 2% for aspergillus. There were significant changes in the pattern of opportunistic infections between the 2 time periods. Mycobacterial infections decreased considerably in the HIV group (17.9 vs. 8.5%, P=0.02), while the incidence of P. jiroveci decreased mainly in the transplant group (32.6 vs. 7.9%, P<0.00001). This study demonstrates a changed pattern of pulmonary infections in immunocompromised patients diagnosed by BAL. The overall diagnostic yield of BAL remains high in immunocompromised patients with respiratory symptoms.

Invasive pulmonary aspergillosis: role of early diagnosis and surgical treatment in patients with acute leukemia

BackgroundAspergillus is a ubiquitous soil-dwelling fungus known to cause significant pulmonary infection in immunocompromised patients. The incidence of aspergillosis has increased during the past two decades and is a frequently lethal complication of acute leukemia patients that occurs following both chemotherapy and bone marrow transplantation. The diagnosis of invasive pulmonary aspergillosis (IPA) according to the criteria that are established by European Organization for the Research and Treatment of Cancer and Mycoses Study Group raise difficulties in severely ill patients. Despite established improvements in field of diagnosis (galactomannan antigen, quantitative PCR, real-time PCR for Aspergillus spp., and findings of computed tomography) and treatment with new antifungals, it is still a major problem in patients with acute leukemia. However, prompt and effective treatment of IPA is crucial because most patients will need subsequent chemotherapy for underlying hematologic disease as soon as possible.Case presentationWe report a 33-year-old male patient with acute promyelocytic leukemia diagnosed in 1993 that developed invasive pulmonary aspergillosis due to A. flavus at relapse in 2003. The patient was successfully treated with liposomal amphotericin B and underwent surgical pulmonary resection. The operative course was uneventful.ConclusionThis report emphasizes the clinical picture, applicability of recent advances in diagnostic and therapeutic approaches for IPA. For early identification of a patient infected with IPA, a high index of suspicion and careful clinical and radiological examinations with serial screening for galactomannan should be established. If aspergillosis is suspected, anti-aspergillosis drug should be administered immediately, and if a unique pulmonary lesion remains, surgical resection should be considered to prevent reactivation during consecutive chemotherapy courses and to improve the outcome.

Epidemiology of nosocomial fungal infections: invasive aspergillosis and the environment

The incidence rates of invasive aspergillosis have increased dramatically during the last two decades, and, despite all diagnostic and therapeutic efforts, outcome is often fatal. Therefore, preventive measures are of major importance in the control of invasive aspergillosis, and require full understanding of the epidemiology of this devastating disease. The environment has been suggested to play a crucial role in the epidemiology of invasive aspergillosis. Aspergillus spores are released in the air and may remain airborne for prolonged periods. As a result, spores are ubiquitously found in air and contaminate anything in contact with air. It has been hypothesized that the inhalation of airborne Aspergillus spores, either directly or through intermediate nasopharyngeal colonization, is a direct cause of pulmonary infection in immunocompromised patients. Recently, water has been suggested as an additional source of “airborne” Aspergillus spp. This review summarizes the current knowledge on the role of the environment in the epidemiology of invasive aspergillosis.

Pulmonary infections in immunocompromised patients who do not have acquired immunodeficiency syndrome: a systematic approach.

Immunocompromised patients are susceptible to infections by organisms that infect individuals with normal immunity and by organisms that affect only those with abnormalities in their immune system. Using the radiographic findings and incorporating clinical information allows for the creation of a useful list differential diagnoses. The nature of the immune defect must be defined because defects in the different parts of the immune system are associated with infections by specific organisms. The time interval since transplantation provides a diagnostic clue because infections tend to occur at certain time intervals after transplantation. An epidemiologic history provides a history of exposure to organisms that may produce pneumonia. Consideration of the therapy the patient has received provides additional clues to the cause of the pneumonia. The physical examination and laboratory studies may provide an indication of the cause of the infection. Organisms tend to produce infections that have a typical rate of clinical development. Classifying the presentation as acute, subacute, or chronic provides additional etiologic clues. Correlating the clinical information with the radiographic findings generates a list of the most likely causative organisms. The list is useful in deciding on additional diagnostic tests and guiding therapy.

Diagnostic Value of Protected BAL in Diagnosing Pulmonary Infections in Immunocompromised Patients

To assess the diagnostic utility of protected BAL (P-BAL) in respiratory infections in immunocompromised patients and to examine whether P-BAL alone could substitute the combined use of protected specimen brush (PSB) and BAL in such patients. Thirty-seven immunocompromised patients who underwent PSB, P-BAL, and BAL simultaneously for the diagnosis or exclusion of bacterial or nonbacterial opportunistic respiratory infections were studied prospectively. The P-BAL was performed through the inner catheter of a telescoping plugged catheter with 60 mL of saline solution. Thirteen (35%) cases of bacterial pneumonia were diagnosed. PSB obtained seven true-positive (TP) results, P-BAL obtained nine, and BAL obtained eight TP. Results of the three techniques were positive and concordant in 6 of the 13 cases. PSB remained free of contamination from oropharyngeal flora in all cases, P-BAL was contaminated twice, and BAL was contaminated in four cases. Opportunistic respiratory infections were diagnosed in 19 patients. P-BAL results were identical to those with BAL in all cases: 18 TP and 1 false-negative. The average volume of P-BAL fluid retrieved was 19 mL, sufficient for all microbiologic and cytologic processings. P-BAL was more time-consuming than both PSB and BAL procedures and was technically more complex. P-BAL alone can substitute the combined use of both PSB and BAL in immunocompromised patients and attains a higher sensitivity than PSB in diagnosing bacterial pneumonia. The combined strategy continues to be a good choice, but due to the high incidence of bacterial pneumonia in these patients, a highly efficient diagnostic procedure is required not only for nonbacterial opportunistic respiratory infections but also for bacterial pneumonia.

Diagnosis of pulmonary infections in immunocompromised patients by fiber-optic bronchoscopy with bronchoalveolar lavage and serology.

Fiber-optic bronchoscopy (FOB) and bronchoalveolar lavage (BAL) were performed on 67 occasions in 57 immunocompromised patients with symptoms consistent with pulmonary infection. Diagnosis was achieved more often in renal transplant patients than in patients with hematological malignancies (85% versus 28%). Culture (bacteria, virus, fungi), staining and microscopy (bacteria, fungi, Pneumocystis carinii (PC)) and antigen detection by indirect immunofluorescence (cytomegalovirus (CMV), respiratory viruses, PC, Legionella) were used for diagnosis. On 20 occasions transbronchial biopsies with histopathologic examination were performed. In addition, serology comprising the herpes group (HHV-6) and respiratory viruses was done. A microbial diagnosis was obtained on 45% of occasions. The most common pathogens found were CMV (31%) and PC (25%). On 22 (33%) occasions a rapid diagnosis of 1 or more microbial agents was obtained within 24 h by conventional staining or indirect immunofluorescence. The clinical relevance of findings of CMV, HHV-6, and Epstein-Barr virus in BAL by polymerase chain detection on 18, 6 and 3 occasions is discussed. On 4 occasions pathogenic bacteria were found. It was not possible to relate findings of coagulase-negative staphylococci, alpha-streptococci and Candida albicans to the pulmonary infection.