Legionella pneumonia in chronic granulomatous disease

Chronic granulomatous disease: a review of the infectious and inflammatory complications

Chronic Granulomatous Disease is the most commonly encountered immunodeficiency involving the phagocyte, and is characterized by repeated infections with bacterial and fungal pathogens, as well as the formation of granulomas in tissue. The disease is the result of a disorder of the NADPH oxidase system, culminating in an inability of the phagocyte to generate superoxide, leading to the defective killing of pathogenic organisms. This can lead to infections with Staphylococcus aureus, Psedomonas species, Nocardia species, and fungi (such as Aspergillus species and Candida albicans). Involvement of vital or large organs can contribute to morbidity and/or mortality in the affected patients. Major advances have occurred in the diagnosis and treatment of this disease, with the potential for gene therapy or stem cell transplantation looming on the horizon.

Problem pathogens: paediatric legionellosis—implications for improved diagnosis

Legionnaires' disease is an established and frequent cause of pneumonia in adults but is thought to be a rare cause in children. We reviewed the medical literature for cases of Legionnaires' disease in children and analysed the epidemiology, clinical characteristics, and treatment. 76 cases of legionella infection in children were identified. In 56%, diagnosis was made with culture methodology. 46% were community-acquired infections. 51.5% were under 2 years of age. 78% of the patients had an underlying condition such as malignancy. Fever, cough, and tachypnoea were the most common symptoms. The overall mortality rate was 33% and was higher in immunosuppressed children and in children younger than the age of 1 year. Patients who were treated empirically with anti-legionella therapy had a notably lower mortality rate compared with patients on inappropriate therapy (23%vs 70%). In 88% of hospital-acquired cases, an environmental link to potable water colonised with legionella was identified. We found no clinical features unique to Legionnaires' disease in children that would allow differentiation from pneumonia due to other respiratory pathogens. Awareness of legionella as a potential cause of paediatric pneumonia is particularly important because infection can be severe and life threatening and antimicrobial therapy often used for empirical therapy in children is not effective against legionella. In any case of pneumonia unresponsive to antibiotics, Legionnaires' disease should be considered and specific diagnostic tests to verify this diagnosis should be done. As legionella diagnostic tests become more widely applied, we predict that legionellosis may appear as an emerging infectious disease in children.

Infections in patients with inherited defects in phagocytic function

Patients with defects in phagocytic function are predisposed to intracellular microorganisms and typically have early dissemination of the infection. Recognition of the underlying disorder and aggressive antimicrobial therapy has been beneficial for the patients. Improved understanding of the pathophysiology has also affected patient management by allowing specific, targeted immunomodulatory intervention. The disorders described in this review are not common but have had a significant impact on our understanding of the role of phagocytic cells in host defense. Conversely, understanding the role of the neutrophil and macrophage in infection has benefited not just the patients described in this review but also other patients with similar disease processes.

Nocardia infection in chronic granulomatous disease

To determine the clinical characteristics and outcome of Nocardia infection in patients with chronic granulomatous disease (CGD), we reviewed data on 28 episodes of Nocardia infection in 23 patients with CGD. All episodes involved pulmonary infection. The frequency of disseminated nocardiosis was 25% for the case series overall, but it was 56% among episodes in patients receiving neither interferon-gamma (IFN-gamma) nor sulfonamide prophylaxis. Patients receiving prophylaxis with IFN-gamma and/or a sulfonamide were significantly less likely to have disseminated nocardiosis than were patients not receiving these medications, and no patient receiving both medications developed disseminated nocardiosis. One-third of the patients had concomitant fungal infections, and 2 patients had concomitant Legionella infections. The majority of patients were successfully treated with a sulfonamide-containing regimen, even though some patients had developed Nocardia infection while receiving sulfonamide prophylaxis. Nocardia infections in patients with CGD are not usually fatal if treated properly, and prophylaxis with IFN-gamma and a sulfonamide may protect against dissemination.

Cytosolic components of the respiratory burst oxidase: resolution of four components, two of which are missing in complementing types of chronic granulomatous disease

The respiratory burst oxidase of neutrophils can be activated in a cell-free system in which plasma membranes, cytosol, Mg2+, and a membrane-perturbing detergent, such as arachidonate or sodium dodecyl sulfate, are all required. Using the technique of preparative isoelectric focusing, the cytosol factor required for oxidase activation was resolved into four components termed C1-C4 with respective pI values of approximately 3.1, 6.0, 7.0, and 9.5. Individually, these components were incapable of activating the oxidase and could only be detected in the presence of suboptimal amounts of normal cytosol that served to supply at least a limited amount of each of the required components. Attempts to activate the oxidase with a combination of the four components failed, suggesting that there might be a yet undetected fifth cytosolic component. Patients with autosomal recessive cytochrome b-positive chronic granulomatous disease (type II CGD) are severely deficient in cytosol factor activity. When added to cytosol samples from two patients with this form of CGD, component C4 restored the ability of each patient's cytosol to activate dormant oxidase. None of the other three cytosol factor components (C1-C3) was effective in this regard, a finding supported by the direct demonstration that these three components were present in normal amounts in this type of CGD. A different form of type II CGD was identified in a third patient on the basis of complementation studies in which the patient's cytosol was able to activate the oxidase in the cell-free system when mixed with cytosol from one of the first two patients. The defect in this third patient's cytosol could be partially corrected by component C2, but not component C4, obtained from normal cytosol. These findings indicate that the role of cytosol in the activation of the respiratory burst oxidase is more complex than previously appreciated in that at least four cytosolic components appear to be required. Defects in two of these components have now been identified and appear to be responsible for two biochemically distinct forms of CGD.

Direct and indirect pathogenicity of beta-lactamase-producing bacteria in mixed infections in children

The recent emergence of numerous aerobic and anaerobic beta-lactamase-producing bacterial strains has been associated with an increase in the failure rate of penicillins in the therapy of infection caused by these organisms. These include respiratory tract, skin of soft tissue, female genital tract, intra-abdominal, and other miscellaneous infections. The important aerobic beta-lactamase-producing bacteria (BLPB) include Staphylococcus aureus, Branhamella catarrhalis, Haemophilus sp., Neisseria gonorrhoeae, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Legionella sp. The anaerobic BLPB are all Bacteroidiaceae and include Bacteroides fragilis group, B. melaninogenicus group, B. oralis, B. oris-buccae, and Fusobacterium sp. Laboratory, animal, and clinical studies that support the indirect pathogenicity of these organisms and the distribution of these BLPB in various infections are reviewed. BLPB may not only have a direct pathogenic role in causing the infection, but also an indirect pathogenic role. The indirect pathogenicity of these organisms is apparent through their ability not only to survive penicillin therapy, but also to protect penicillin-susceptible pathogens from that drug. These direct and indirect virulence characteristics of aerobic and anaerobic BLPB require the administration of appropriate antimicrobial therapy directed against all pathogens in mixed infections.

Chronic granulomatous disease due to a defect in the cytosolic factor required for nicotinamide adenine dinucleotide phosphate oxidase activation

The superoxide-generating enzyme of human neutrophils, NADPH oxidase, is present in a dormant state in unstimulated neutrophils. It can be converted to an active form in a cell-free system if both the plasma membrane and cytosol fractions are incubated together in the presence of arachidonic acid. This system was used to determine the nature of the biochemical defect in seven patients with the autosomal recessive, cytochrome b-positive form of chronic granulomatous disease (CGD). A severe deficiency in the cytosol factor was identified in each patient. The defective activity was not caused by the presence of an inhibitor, nor could it be restored to normal by combining cytosol fractions from different patients. In contrast, the membrane fractions from all seven patients contained normal levels of NADPH oxidase when activated in the presence of control cytosol. Of family members tested (obligate heterozygotes for this disorder), seven of eight had intermediate levels of cytosol factor activity. The respiratory burst defect in this form of CGD is caused by an abnormality in the cytosolic factor required for NADPH oxidase activation.

Defective monocyte oxidative metabolism in a child with non-pneumonic legionellosis

A case of non-pneumonic legionellosis with gastrointestinal manifestations is described in a 13-year-old boy without premorbidity. A selective defect in monocyte oxidative metabolism was found and consistently demonstrated throughout the following year. We suggest that the observed monocyte deficiency may have facilitated the development of legionnaires disease and that otherwise normal monocyte function may have contributed to the favourable course of disease.

Infectious complications of the primary immunodeficiencies

The primary manifestation of the immunodeficiencies is undue susceptibility to infection. This means too many, too severe, too prolonged, too complicated and too unusual infections. Infections in immunodeficiency have a characteristic cause depending on the nature of the immune deficiency. Antibody deficiencies are associated with infections with gram-positive infections. Cellular immune deficiencies are associated with mycobacterial, protozoan, fungus, virus, and opportunistic bacterial infection. Phagocytic disorders are associated with staphylococcal, fungal, and gram-negative organisms. Complement disorders are associated by neisserial infections. Infections have also been implicated in the pathogenesis of some immunodeficiencies in some circumstances. These include human T lymphotropic virus type III (HTLV-III), rubella virus, cytomegalovirus, and Epstein-Barr virus. Several infectious syndromes in specific immunodeficiencies have been identified. Examples include enteric cytopathic human orphan (ECHO) virus encephalitis in agammaglobulinemia, and meningococcal meningitis in C6 deficiency. Infections can also be induced by live vaccines given in immunodeficiency (e.g., paralytic polio in agammaglobulinemia.) Unusual infectious syndromes will be illustrated including parainfluenza infection in severe combined and immunodeficiency, Legionella pneumonia in chronic granulomatous disease, and Cryptosporidium infection in hyper-IgM immunodeficiency.