Intracerebral Nocardia asteroides abscess treated by neurosurgical aspiration and combined therapy with sulfadiazine and cefotaxime

Primary Nocardia brain abscesses and role of intraventricular antibiotic therapy

Intracranial infections caused by Nocardia Farcinica are challenging to treat and potentially lethal because of the organism's tendency to resist antibiotics and high relapse rates. Such infections usually occur in immunocompromised patients who have predisposing factors. Nocardia brain abscesses carry a higher morbidity and mortality rate than other bacterial brain abscesses, with reported mortality rates of 55% (even up to 90% in cases of late diagnosis) in immunocompromised patients. An aggressive therapeutic approach is required and an early identification of the microorganism is paramount. Given the high microbial resistance, it is usually an infection with a low cure rate. We present the case of a patient with primary brain abscesses due to Nocardia Farcinica, successfully treated with intrathecal Amikacin administration through ventricular drain, in addition to surgical evacuation and intravenous antibiotic therapy. In this case, clinical and radiological improvement were observed once the intrathecal treatment was started. To our best knowledge, no cases of intraventricular use of Amikacin have been previously reported to treat this type of infection and we believe that it may be useful in properly selected patients.

Isolated Nocardiosis, an Unrecognized Primary Immunodeficiency?

Nocardiosis is an infectious disease caused by the gram-positive bacterium Nocardia spp. Although it is commonly accepted that exposure to Nocardia is almost universal, only a small fraction of exposed individuals develop the disease, while the vast majority remain healthy. Nocardiosis has been described as an "opportunistic" disease of immunocompromised patients, suggesting that exposure to the pathogen is necessary, but a host predisposition is also required. Interestingly, increasing numbers of nocardiosis cases in individuals without any detected risk factors, i.e., without overt immunodeficiency, are being reported. Furthermore, a growing body of evidence have shown that selective susceptibility to a specific pathogen can be caused by a primary immunodeficiency (PID). This raises the question of whether an undiagnosed PID may cause nocardiosis affecting otherwise healthy individuals. This review summarizes the specific clinical and microbiological characteristics of patients with isolated nocardiosis published during the past 30 years. Furthermore, it gives an overview of the known human immune mechanisms to fend off Nocardia spp. obtained from the study of PIDs and patients under immunomodulatory therapies.

Sulfonamides without trimethoprim in the treatment of Nocardia infections: A case report and literature review

Sulfonamides are recommended as part of first-line therapy for most Nocardia infections, with trimethoprim-sulfamethoxazole (TMP-SMX) considered the drug of choice for susceptible isolates. However, in the case of central nervous system, disseminated disease, and other serious Nocardia infections, TMP-SMX should not be used as monotherapy. The preferred treatment for a patient unable to take TMP-SMX because of allergy or intolerance remains uncertain. Prior to the availability of TMP-SMX in 1973, other sulfonamides were mainstays of treatment. We describe a Nocardia infection successfully treated with sulfadiazine in a lung transplant recipient who could not tolerate TMP-SMX. A review of similar cases reported in the literature provides insight into the successful treatment of Nocardia infections with sulfonamide regimens not containing trimethoprim in transplant recipients and other immunocompromised hosts.

Nocardia farcinica Brain Abscess: Report of 3 Cases

BACKGROUND

Central nervous system nocardial infection is a rarely reported disease that usually affects patients with predisposing and debilitating conditions but also the immunocompetent population. The most common variant affecting the brain is Nocardia farcinica. Management of brain nocardiosis is troublesome and requires consideration of the severity of the underlying systemic disease, the difficulties in identifying the bacterium, and the frequent delay in initiating adequate therapy.

CASE DESCRIPTION

We present 3 cases of N. farcinica brain abscess (single, multiloculated, and multifocal) diagnosed in 3 patients with predisposing factors that could be successfully cured. The patients underwent craniotomy, evacuation of the purulent collection, and partial resection of the abscesses' walls. Confirmation of N. farcinica species was achieved using specific polymerase chain reaction sequencing of the 16S ribosome RNA gene. Antibiotic therapy was selected on susceptibility tests and was maintained for 10 months (1 case) and 12 months (2 cases).

CONCLUSIONS

Brain nocardiosis needs to be suspected primarily (though not exclusively) in immunocompromised patients presenting with neurologic deficit and harboring intracerebral lesions resembling brain tumors. Early identification of the specific species is paramount in order to initiate long-term antibiotic therapy, acknowledging the inherent resistance of N. farcinica to third-generation cefalosporins and its susceptibility to trimethoprim-sulphamethoxazole. According to the literature, surgical excision or aspiration of the brain abscess seems to provide good chances of eradication of the disease. In our experience, successful outcome was achieved with subtotal resection and prolonged and adequate antibiotic therapy.

Case series: Nocardiosis of the brain and lungs

Localized and multisystem nocardiosis is an opportunistic disease that occurs commonly in immunocompromised patients. Rarely, it is also seen in immunocompetent individuals. The lungs and brain are commonly involved. Typical, but nonspecific, findings are often seen on imaging and the presence of concomitant lesions in these two systems often suggests this diagnosis. We report two cases of cerebral and pulmonary involvement by nocardiosis.

Syncope on steroids

An 83-year-old white woman sought medical attention because of a three-day history of slurred speech and an episode of syncope. Her medical history included long-standing rheumatoid arthritis treated with prednisone for the past five years (60 mg/day at presentation). In addition, cyclosporin (200 mg/day) had been started 16 months earlier for necrotizing scleritis.

Nocardia farcinica brain abscess: a case report and review of the literature

Nocardia infection is not rare as generally been assumed and its mortality rate is high. It is isolated from plants and soil in most regions of the world. The hosts usually have predisposing conditions and the infection is acquired through the respiratory tract or skin. Nocardial organisms have a tendency to disseminate hematogenously from the primary site of infection to brain, kidney, joints, bones and eyes. Sulfonamides are preferred empirically for the treatment. Because of high relapse rates, the treatment must be continued for 12 months. In nocardia farcinica infection, the characteristic resistance pattern to cephalosporines must be kept in mind. In this article, a rare case of nocardia farcinica infection with a solitary cerebral abscess is presented and the literature is reviewed.

Nocardiosis in systemic lupus erythematosus

OBJECTIVES

This study was performed to study the clinical presentations, treatment, and outcome of six cases of nocardial infection in the systemic lupus erythematosus (SLE) population living in Hong Kong and compare these cases with those reported in the English literature.

METHODS

Records of 215 SLE patients who attended our lupus and rheumatology clinics were reviewed, and cases of nocardial infection were retrieved and studied in detail. A Medline search from 1966 to 1995 was performed to identify other reported cases. The microbiology, diagnosis, and treatment strategies of nocardiosis were assessed.

RESULTS

Six cases of nocardiosis were found in our lupus series, giving a prevalence of 2.8%. Another 26 cases of nocardial infection in SLE were reported in the literature. All except one were caused by Nocardia asteroides. The lung was the commonest site of involvement (81%), followed by the central nervous system (CNS) (13%). The mortality was high (35%), especially when the CNS was involved (75%). Sulphonamides were the mainstay of treatment, and adjunctive surgical procedures may be needed for suppurative complications.

CONCLUSIONS

Nocardiosis has been increasingly recognized in SLE. Although still uncommon, it is an important opportunistic infection because it is curable and mortality is usually caused by delay in diagnosis and treatment. A high index of suspicion, an aggressive approach to diagnosis, and early empirical therapy are essential principles of management.

Nocardial brain abscess: treatment strategies and factors influencing outcome

The successful management of nocardial brain abscess remains problematic. The authors report 11 cases of nocardial brain abscess treated between 1971 and 1993 and review 120 cases reported since 1950. The clinical findings included focal deficits in 55 patients (42%), nonfocal findings in 36 (27%), and seizures in 39 (30%). Extraneural nocardiae were present in 66% of the cases; pulmonary (38%) and cutaneous/subcutaneous (20%) locations were the most frequent. The abscesses were single in 54% of the patients, multiple in 38%, and of unknown number in 8%. Forty-four of 131 patients (34%) were immunocompromised; since 1975, 18 of 40 immunocompromised patients (45%) were transplant recipients and six (15%) had human immunodeficiency virus. The mortality rate was 24% after initial craniotomy and excision (11/45), 50% after aspiration/drainage (17/34), and 30% after nonoperative therapy (7/23); 29 cases (22%) were diagnosed at autopsy. The mortality rate was 33% in patients with single abscesses and 66% in those with multiple abscesses (P < 0.0003). There was no difference in the mortality rates of immunocompromised and nonimmunocompromised patients treated before computed tomography (CT) was available; since the advent of CT, however, the mortality rate has been significantly higher in immunocompromised patients (55% vs. 20%, P < 0.05). Although the mortality rate for nocardial brain abscesses has dropped almost 50% since the advent of CT, it has remained virtually unchanged in immunocompromised patients and is three times higher than that of other bacterial brain abscesses (30% vs. 10%). The authors recommend image-directed stereotactic aspiration for diagnosis; however, craniotomy and total excision are necessary in most cases, because nocardial abscesses are usually multiloculated. Patients with minimal neurological deficits or small abscesses may be treated initially with antibiotics alone. Sulfonamides, alone or in combination with trimethoprim, are most effective and should be continued for at least 1 year. Minocycline, imipenem, or aminoglycoside in combination with a third-generation cephalosporin may be used with reasonably good success as second-line agents in cases of allergy or nonresponsiveness to sulfa agents.

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.

Multiple nocardial brain abscesses: report of two patients

Two patients presented with nocardial brain abscesses, one as secondary to overwhelming pulmonary infection following a thoracic empyema, the second as a primary abscess. Both patients had immunopression. Such an infection should be considered early in any patient who is immunocompromised.