Nocardia caviae: a report of 13 new isolations with clinical correlation

Severe pneumonia due to Nocardia otitidiscaviarum identified by mass spectroscopy in a cotton farmer: A case report and literature review

RATIONALE

Nocardia species are aerobic saprophytic bacilli. Among Nocardia species, Nocardia otitidiscaviarum (N otitidiscaviarum) is rarely reported in pulmonary infection.

PATIENT CONCERNS

We reported a case of N otitidiscaviarum pneumonia in a cotton farmer.

DIAGNOSES

N otitidiscaviarum pneumonia was identified by mass spectroscopy.

INTERVENTIONS

Combined treatments (amikacin, imipenem and trimethoprim-sulfamethoxazole) were administered after identification of N otitidiscaviarum.

OUTCOMES

The patient eventually died from severe respiratory insufficiency in the hospital.

LESSONS

Early precise diagnosis and prompt combined therapy are of vital importance in severe Nocardia pulmonary infection.

Pulmonary nocardiosis from a tertiary care hospital in Southern India

The present study highlights eight cases of pulmonary nocardiosis diagnosed during the time period of January 2006-March 2008. Nocardia otitidiscaviarum, N. asteroides and N. brasiliensis were isolated from these cases. Whereas six patients were treated successfully, one showed partial response and one case expired before the institution of treatment. Early and correct microbiological diagnosis can help to decrease the disease-related morbidity and mortality.

Comparative Pathology of Nocardiosis in Marine Mammals

Nocardia spp. infections in mammals cause pyogranulomatous lesions in a variety of organs, most typically the lung. Members of the Nocardia asteroides complex are the most frequently recognized pathogens. Nine cases of nocardiosis in free-ranging pinnipeds and 10 cases of nocardiosis in cetaceans were evaluated. Host species included the hooded seal ( Cystophora cristata, n = 8), leopard seal ( Hydrurga leptonyx, n = 1), Atlantic bottlenose dolphin ( Tursiops truncatus, n = 4), beluga whale ( Delphinapterus leucas, n = 4), and killer whale ( Orcinus orca, n = 2). The most common presentation of nocardiosis in both pinnipeds and cetaceans was the systemic form, involving 2 or more organs. Organs most frequently affected were lung and thoracic lymph nodes in 7 of 9 cases in pinnipeds and 8 of 10 cases in cetaceans. Molecular identification and bacterial isolation demonstrated a variety of pathogenic species. N. asteroides, N. farcinica, N. brasiliensis, and N. otitisdiscaviarum are pathogenic for pinnipeds. In cetaceans N. asteroides, N. farcinica, N. brasiliensis, N. cyriacigeorgica, and N. levis are pathogenic. Hematoxylin and eosin and acid fast staining failed to reveal bacteria in every case, whereas modified acid fast and Grocott's methenamine silver consistently demonstrated the characteristic organisms. In both pinnipeds and cetaceans, juvenile animals were affected more often than adults. Hooded seals demonstrated more cases of nocardiosis than other pinnipeds.

A case series and focused review of nocardiosis: clinical and microbiologic aspects

Nocardia species are ubiquitous soil organisms that often infect patients with underlying immune compromise, pulmonary disease, or a history of surgery or trauma. We report 5 cases of nocardiosis representing various aspects of this "great imitator": 1) pneumonia in the setting of underlying malignancy, 2) chronic pneumonia with drug-resistant organism, 3) bacteremia and empyema with chronic hematologic malignancy, 4) primary cutaneous disease, and 5) sternal wound infection. We present a summary of the English literature from 1966 to 2003 with a focus on the teaching points of each of our 5 cases as well as the background epidemiology and microbiology of the Nocardia genus. Isolation of the organism may be achieved with routine media but longer incubation times may be necessary, delaying diagnosis and appropriate therapy. Treatment with a sulfa-containing regimen is standard of care, but resistance testing is warranted given emerging drug resistance, high rates of discontinuation due to adverse reactions, and the potential for nephrotoxicity in transplant recipients on cyclosporine.

Nocardia farcinica pneumonia in chronic granulomatous disease

Infection with Nocardia poses a diagnostic challenge in patients with chronic granulomatous disease (CGD) because the signs and symptoms are often nonspecific, delay in diagnosis is common, and invasive procedures are frequently required to obtain appropriate tissue specimens. We present the first reported case of N farcinica pneumonia in an adolescent with X-linked CGD. Differentiation of N farcinica from other members of N asteroides complex is important because of its propensity for causing disseminated infection and antimicrobial resistance. Physicians caring for patients with CGD should maintain a high index of suspicion for nocardiosis, especially in those receiving chronic steroid therapy. Early diagnosis remains critical for decreased morbidity and occasional mortality.

The medically important aerobic actinomycetes: epidemiology and microbiology

The aerobic actinomycetes are soil-inhabiting microorganisms that occur worldwide. In 1888, Nocard first recognized the pathogenic potential of this group of microorganisms. Since then, several aerobic actinomycetes have been a major source of interest for the commercial drug industry and have proved to be extremely useful microorganisms for producing novel antimicrobial agents. They have also been well known as potential veterinary pathogens affecting many different animal species. The medically important aerobic actinomycetes may cause significant morbidity and mortality, in particular in highly susceptible severely immunocompromised patients, including transplant recipients and patients infected with human immunodeficiency virus. However, the diagnosis of these infections may be difficult, and effective antimicrobial therapy may be complicated by antimicrobial resistance. The taxonomy of these microorganisms has been problematic. In recent revisions of their classification, new pathogenic species have been recognized. The development of additional and more reliable diagnostic tests and of a standardized method for antimicrobial susceptibility testing and the application of molecular techniques for the diagnosis and subtyping of these microorganisms are needed to better diagnose and treat infected patients and to identify effective control measures for these unusual pathogens. We review the epidemiology and microbiology of the major medically important aerobic actinomycetes.

Nocardia species: host-parasite relationships

The nocardiae are bacteria belonging to the aerobic actinomycetes. They are an important part of the normal soil microflora worldwide. The type species, Nocardia asteroides, and N. brasiliensis, N. farcinica, N. otitidiscaviarum, N. nova, and N. transvalensis cause a variety of diseases in both normal and immunocompromised humans and animals. The mechanisms of pathogenesis are complex, not fully understood, and include the capacity to evade or neutralize the myriad microbicidal activities of the host. The relative virulence of N. asteroides correlates with the ability to inhibit phagosome-lysosome fusion in phagocytes; to neutralize phagosomal acidification; to detoxify the microbicidal products of oxidative metabolism; to modify phagocyte function; to grow within phagocytic cells; and to attach to, penetrate, and grow within host cells. Both activated macrophages and immunologically specific T lymphocytes constitute the major mechanisms for host resistance to nocardial infection, whereas B lymphocytes and humoral immunity do not appear to be as important in protecting the host. Thus, the nocardiae are facultative intracellular pathogens that can persist within the host, probably in a cryptic form (L-form), for life. Silent invasion of brain cells by some Nocardia strains can induce neurodegeneration in experimental animals; however, the role of nocardiae in neurodegenerative diseases in humans needs to be investigated.

Nocardia species: host-parasite relationships

The nocardiae are bacteria belonging to the aerobic actinomycetes. They are an important part of the normal soil microflora worldwide. The type species, Nocardia asteroides, and N. brasiliensis, N. farcinica, N. otitidiscaviarum, N. nova, and N. transvalensis cause a variety of diseases in both normal and immunocompromised humans and animals. The mechanisms of pathogenesis are complex, not fully understood, and include the capacity to evade or neutralize the myriad microbicidal activities of the host. The relative virulence of N. asteroides correlates with the ability to inhibit phagosome-lysosome fusion in phagocytes; to neutralize phagosomal acidification; to detoxify the microbicidal products of oxidative metabolism; to modify phagocyte function; to grow within phagocytic cells; and to attach to, penetrate, and grow within host cells. Both activated macrophages and immunologically specific T lymphocytes constitute the major mechanisms for host resistance to nocardial infection, whereas B lymphocytes and humoral immunity do not appear to be as important in protecting the host. Thus, the nocardiae are facultative intracellular pathogens that can persist within the host, probably in a cryptic form (L-form), for life. Silent invasion of brain cells by some Nocardia strains can induce neurodegeneration in experimental animals; however, the role of nocardiae in neurodegenerative diseases in humans needs to be investigated.

Infection with Nocardia species in Queensland. A review of 102 clinical isolates

OBJECTIVE

To review the species distribution, pathologic significance and disease associations of clinical isolates of Nocardia and related bacteria in Queensland, and to examine the characteristics, treatment and outcome of patients infected with these organisms.

DESIGN AND SETTING

A retrospective review of Queensland State Health Laboratory records provided microbiological data for Nocardia isolates referred from other laboratories during the period January 1983 to December 1988. Clinical information was extracted from hospital case notes, or obtained from detailed questionnaires completed by attending physicians. Nocardia isolates were classified as "significant" if specific treatment for nocardiosis was given, or on the basis of autopsy findings.

PATIENTS

One hundred and two patients had a Nocardia species or a related organism isolated from clinical specimens during the study period.

RESULTS

The 102 isolates included Nocardia asteroides (45), N, brasiliensis (35), N. caviae (5) and N. transvalensis (5). Clinical results were available for 93 patients, of whom 74 (80%) had a significant isolate recovered. Primary pulmonary or disseminated disease occurred in 35 patients, and was caused mainly by N. asteroides. Significant infections of skin and soft tissues, primarily due to N. brasiliensis, were found in 39 patients. Preexisting lung disease and treatment with steroids and immunosuppression were risk factors for pulmonary and disseminated nocardiosis. A history of inoculation in an outdoor setting was frequent in patients with cutaneous disease. Antibiotic regimens that included trimethoprim-sulfamethoxazole or another sulfonamide agent were used to treat the majority of patients with significant infection. Deaths were confined to those with pulmonary and disseminated disease, with a case fatality rate of 40% in that group.

CONCLUSION

Infection with Nocardia species appears to be more common than is generally appreciated. The local species distribution and disease spectrum are similar to those described elsewhere. A high index of suspicion for nocardiosis should be maintained in susceptible hosts with pulmonary infiltrates, particularly when there is evidence for metastatic infection, and in patients with superficial infections and a history of outdoor injury.

Blood-borne pulmonary infection with Nocardia asteroides in a heroin addict

Nocardia asteroides frequently causes primary lung infection with possible hematogenous dissemination to various organs, especially in patients with altered immune responses. The preponderance of pulmonary infections suggests an airborne route of contamination. We report a case of pulmonary nocardiosis in a previously healthy intravenous heroin abuser. The clinical and epidemiologic data strongly suggest a paraphernalia blood-borne infection in this patient, a mode of contamination which has not been previously reported.

Nocardial infection of the skin

This paper describes the relationship between different forms of nocardia infection involving the skin. The best recognized of these conditions are systemic nocardiosis and actinomycetoma due to Nocardia spp. in which the organisms are present in either filamentous or grain form respectively. Attention is drawn to evidence for the existence of a primary cutaneous form of nocardiosis which follows inoculation and in which the organisms grow in filamentous phase. It is not clear whether such cases can progress to mycetoma formation if left untreated, or whether other factors are involved. The clinical and laboratory features of these different clinical varieties of nocardia infection are discussed.

Endogenous ocular nocardiosis: a clinical and experimental study

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Role of L-forms of Nocardia caviae in the development of chronic mycetomas in normal and immunodeficient murine models

Single-cell suspensions of Nocardia caviae 112 were injected into normal, athymic, and asplenic mice by several different routes. The 50% lethal dose values, kill curve characteristics, histological and electron microscopic properties, organ clearance patterns, and induction of L-forms during the acute and chronic phase of disease were determined in groups of mice for up to 2 years after infection. From these data we concluded the following. (i) Athymic and asplenic animals were significantly more susceptible to N. caviae than their littermate controls regardless of inoculation route. (ii) All mice were most susceptible to lethal infection after intranasal administration and least affected when the organisms were injected into the peritoneal cavity. (iii) Chronic, progressive disease leading to the formation of mycetomas occurred only in mice injected intravenously. (iv) T-cell-deficient animals were impaired in the development of typical mycetomas. (v) L-forms of N. caviae were induced within immunocompetent hosts, whereas the cell wall-less state of the bacteria was not observed in the immunodeficient animals. (vi) Two colony types of the cell wall-deficient state were isolated from infected animals. (vii) These cell wall-deficient organisms were intimately involved in the pathogenesis of disease and bacterial persistence within the host. Finally (viii), with this strain of Nocardia, cell wall-deficient organisms played a major role in the development of the characteristic bacterial granule formed within the mycetomatous lesions 6 months to 1 year after intravenous inoculation.