Nocardia asteroides infection complicating neoplastic disease

Fever of unknown origin revealing testicular nocardiosis: a case report and literature review

BACKGROUND

Nocardia is an ubiquitous soil organism. As an opportunistic pathogen, inhalation and skin inoculation are the most common routes of infection. Lungs and skin are the most frequent sites of nocardiosis. Testis is a highly unusual location for nocardiosis.

CASE PRESENTATION

We report the case of an immunocompromised 75-year-old-man admitted for fever of unknown origin. He presented with skin lesions after gardening and was first suspected of Mediterranean spotted fever, but he did not respond to doxycycline. Then, physical examination revealed new left scrotal swelling that was compatible with a diagnosis of epididymo-orchitis. The patient's condition did not improve despite empirical antibiotic treatment with the onset of necrotic scrotal abscesses requiring surgery. Nocardia brasiliensis yielded from the removed testis culture. High-dose trimethoprim-sulfamethoxazole and ceftriaxone were started. Multiple micro-abscesses were found in the brain and spinal cord on imaging studies. After 6 weeks of dual antibiotic therapy for disseminated nocardiosis, slight regression of the brain abscesses was observed. The patient was discharged after a 6-month course of antibiotics and remained relapse-free at that time of writing these lines. Trimethoprim-sulfamethoxazole alone is meant to be pursued for 6 months thereafter. We undertook a literature review on previously reported cases of genitourinary and urological nocardiosis; to date, only 36 cases have been published with predominately involvement of kidney, prostate and testis.

CONCLUSIONS

To the best of our knowledge, this is the first case of Nocardia brasiliensis simultaneously infecting skin, testis, brain and spinal cord in an immunocompromised patient. Knowledge on uncommon forms of nocardiosis remains scarce. This case report highlights the difficulty of diagnosing atypical nocardiosis and the importance of prompt bacteriological sampling in case of empirical antibiotics failure.

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.

Prostate abscess caused by Nocardia farcina

Nocardia farcinica usually infects the respiratory tract and can sometimes cause central nervous system infections; however, it rarely infects the prostate. Here we report the first case of N. farcinica detected in the purulence specimen drained from a prostate abscess. A 70-year-old Japanese male receiving steroid and cyclosporine treatment came to our department with chief complaint of turbid urine. Computed tomography revealed a low-density lesion in his prostate. Antibiotic administration and prostatic drainage were effective. N. farcinica was detected in the cultures of urine and prostatic drainage purulence specimens. Nocardiosis should be included in the differential diagnosis in immunosuppressive patients with prostate abscess.

Current knowledge of nocardiosis in teleost fish

Nocardia sp. is the causative agent of nocardiosis, a lethal granulomatous disease of the skin, muscle, and various inner tissues affecting various teleost and shellfish. Four species of Nocardia have been isolated from diseased fish and shellfish, namely Nocardia asteroides, Nocardia seriolae, Nocardia salmonicida and Nocardia crassostreae. Therefore, in fish aquaculture, nocardiosis has caused severe economic losses, especially in the Asian region. Considerable research has been performed, since the first report of identified Nocardia sp. in fish, to characterize Nocardia sp. and identify rapid detection techniques, immune response against infection and prophylactic approaches. In this review, the current state of knowledge about nocardiosis in fish has been presented, including the pathogenesis, diagnosis, host immune response and vaccine development.

Central nervous system infections in cancer patients and hematopoietic stem cell transplant recipients

Central nervous system (CNS) infections in cancer patients present a diagnostic and therapeutic challenge for clinicians. While CNS infections are not frequent complications of cancer, its therapies, or hematopoietic stem cell transplantation, the importance of CNS infections lies in their propensity to result in profound morbidity and substantial mortality in this vulnerable patient population. With an expanding population of patients with malignant disease undergoing more potent and aggressive therapies and with the advent of newer immunomodulatory agents, the incidence of CNS infectious complications is likely to rise. This chapter will summarize the clinical and diagnostic evaluation of potential infections of the CNS in these patients and will discuss particular pathogens of interest with regard to this at-risk patient population.

Nocardia seriolae infection in the three striped tigerfish, Terapon jarbua (Forsskål)

An epizootic in pond cultured three striped tigerfish, Terapon jarbua, in Taiwan was caused by Nocardia seriolae. Diseased fish first showed clinical signs and mortalities in February and March 2003. The cumulative mortality within 2 months was 2.4% (1200 of 50 000) and affected fish were 7 months old with total lengths from 18 to 25 cm. Most affected fish were pale and lethargic with haemorrhages and ulcers on the skin. The most significant gross pathological changes were varying degrees of ascites and enlargement of the spleen, kidney and liver. Obvious white nodules, varying in size, were found in these organs. Bacteria were either coccal or filamentous in appearance, with bead-like forms. Isolates from diseased fish were characterized using the API ZYM (Analytical profile index; Bio Mérieux, France) systems and conventional tests and identified as Nocardia sp. The isolate was designated NS127 and was confirmed as N. seriolae by a polymerase chain reaction assay that gave the expected specific 432 bp amplicon. In addition, its 16S rDNA sequence gave 100% sequence identity with N. seriolae. A partial sequence of the 16S rRNA gene, heat shock protein gene and RNA polymerase gene (rpo B) of NS127 and the type strain of N. seriolae BCRC 13745 formed a monophyletic clade with a high sequence similarity and bootstrap value of 99.9%. White nodules induced in experimental fish were similar to naturally infected cases and N. seriolae was re-isolated on brain heart infusion agar. This is the first report of N. seriolae-infection in three striped tigerfish in aquaculture.

Bacterial Infections

In Osier’s time, bacterial pneumonia was a dreaded event, so important that he borrowed John Bunyan’s characterization of tuberculosis and anointed the pneumococcus, as the prime pathogen, “Captain of the men of death.”1 One hundred years later much has changed, but much remains the same. Pneumonia is now the sixth most common cause of death and the most common lethal infection in the United States. Hospital-acquired pneumonia is now the second most common nosocomial infection.2 It was documented as a complication in 0.6% of patients in a national surveillance study,3 and has been reported in as many as 20% of patients in critical care units.4 Furthermore, it is the leading cause of death among nosocomial infections.5 Leu and colleagues6 were able to associate one third of the mortality in patients with nosocomial pneumonia to the infection itself. The increase in hospital stay, which averaged 7 days, was statistically significant. It has been estimated that nosocomial pneumonia produces costs in excess of $500 million each year in the United States, largely related to the increased length of hospital stay.

A cluster of nocardial brain abscesses

BACKGROUND

Nocardia species are aerobic Gram-positive bacteria that are ubiquitous in the environment. Infection usually occurs through inhalation or direct cutaneous inoculation of the organism. It has been reported that infection is more common in warm, dry climates. Cerebral nocardiosis is an uncommon clinical entity, representing only 2% of all cerebral abscesses. It is an illness associated with significant morbidity and mortality.

CASE DESCRIPTIONS

We report 4 cases of nocardial brain abscesses presenting to TCH, Australia, within a 1-year period. All 4 cases occurred in men without any significant underlying immunocompromise. In 3 of the cases, the diagnosis was only established after craniotomy. All cases were given prolonged antimicrobial therapy. After more than 8 months of follow-up, there have been no deaths or treatment failures. There has been only one other case of nocardial brain abscess at TCH over the past 15 years. We review the current literature on cerebral nocardiosis.

CONCLUSION

Nocardial brain abscesses are uncommonly encountered at our institution. This cluster of 4 cases over a 1-year period has therefore led us to postulate that the severe drought may be aiding in the transmission of the bacteria. The cases also emphasize the propensity of nocardial infections to mimic other conditions, particularly malignancy, which may lead to delays in appropriate surgical treatment and antimicrobial therapy. The diagnosis requires a high clinical index of suspicion, with early tissue and microbiological diagnosis. Prolonged antimicrobial therapy is required to prevent relapse of the infection.

Biochemical Identification and Molecular Characterization (PCR-RFLP) of Nocardia Isolates from Sputum

BACKGROUND

Nocardia identification has been based on biochemical and morphological characteristics. However, molecular biology techniques allow a better characterization of species and biotypes that are related to invasive diseases.

METHODS

Twelve isolates of Nocardia spp. were obtained from sputum of patients with tuberculosis under retreatment. Identification was done based on morphological characteristics, biochemical tests (casein, tyrosine, xanthine, gelatin, and urea) and molecular biology techniques (PCR-RFLP) using restriction enzymes MspI, HinfI, BsaHI, HaeIII and BstEII.

RESULTS

Biochemical tests identified the 12 isolates as Nocardia asteroides. PCR-RFLP technique identified nine isolates to species and biotype level: five as N. asteroides type II, two as N. asteroides type VI, and two as N. asteroides type I. The remaining three isolates were identified as follows: one to species level as N. farcinica and two at genus level as Nocardia sp.

CONCLUSIONS

Significant statistical differences between the use of traditional techniques and PCR-RFLP were not found at genus level, but there were important differences at species and biotype level. Biochemical tests identified correctly the actinomycete isolates as belonging to Nocardia genus, but at N. asteroides complex level were not able to discern among their different species. PCR-RFLP is a rapid, non-expensive, and reliable method that allows to discriminate the N. asteroides complex species, identifying biotypes related to invasive disease. Our results suggest that the hospital environment was not a contamination source.

Epididymo-orchitis and testicular abscess due to Nocardia asteroides complex

Nocardia asteroides complex is a rare human pathogen chiefly affecting immunosuppressed patients. We present the sixth case of epididymo-orchitis attributable to this organism. A 78-year-old man presented to the Mayo Clinic with fever and weight loss after being treated with cyclophosphamide and prednisone for an immune-mediated vasculitis. He was found to have a testicular abscess, and orchiectomy was performed. N. asteroides complex was identified on the wound cultures. Sulfa therapy was begun. In previous case reports, this condition carried a 50% mortality rate. Patients who survive seemed to benefit from aggressive surgical debridement and long-term sulfa therapy.

Pulmonary nocardiosis re-visited: experience of 35 patients at diagnosis

Pulmonary infection by Nocardia is an uncommon opportunistic infection in humans. Thirty-five patients with pulmonary nocardiosis were identified in two tertiary referral hospitals. A retrospective review of the patient characteristics, clinical and laboratory features including antimicrobial susceptibility at diagnosis was carried out. Radiological features derived from chest radiographs and CT scans were also documented. In our population, the predominant risk factors were immuno-compromised state, corticosteroid therapy, and underlying pulmonary pathology. The presenting features were similar to those previously described but disseminated infection was not common. The radiological changes were diverse and non-specific. Nocardia asteroides was the commonest species. Most Nocardia isolates were susceptible to imipenem, ceftriaxone, amikacin, and cotrimoxazole. Co-existing microbial agents are common and reflect the underlying complex disorders.

Nocardiosis in cancer patients

Nocardiosis (NOC) is an important cause of infection in immunocompromised patients. However, large series in patients with cancer have not been described. We review the records of patients with cancer and NOC who were evaluated at The University of Texas M. D. Anderson Cancer Center, Houston, Texas, between 1988 and 2001, and we describe the incidence, microbiologic and clinical characteristics, treatment, and outcome of NOC in this population. Forty-two patients with a total of 43 episodes of NOC were identified (incidence of 60 cases of NOC per 100,000 admissions). Twenty-seven patients (64%) had hematologic malignancies. In 13 patients, NOC complicated bone marrow transplantation. Neutropenia was observed in 4 (10%) of 40 episodes with information available, and lymphopenia in 20 (50%) of 40 episodes. Patients had received steroids for 25 episodes (58%) and had received chemotherapy for 10 episodes (23%) within 30 days before the onset of NOC. Nine episodes of breakthrough NOC were identified in 7 (23%) of the 40 patients with information available. Pulmonary NOC was seen in 30 (70%) of 43 cases; soft-tissue NOC in 7 (16%); central venous catheter-related nocardemia in 3 (7%); and disseminated NOC, central nervous system NOC, and a perinephric abscess each in 1 (2%). Twenty-three percent of patients with pulmonary NOC had an acute presentation. complex was the most common causative species (77%). Therapy for NOC was mainly concurrent trimethoprim/ sulfamethoxazole and either a tetracycline or a beta-lactam. The median duration of treatment was 113 days (range, 10-600 d). Nine (60%) of 15 patients with outcome data died from NOC. NOC, although infrequent, is an important cause of morbidity and mortality in patients with cancer. It has pleomorphic manifestations, and it can be seen as a breakthrough infection. The present study confirms that timely diagnosis, the site of NOC, the type of, the presence of comorbidities, and cytomegalovirus coinfection influence the outcome of patients with cancer and NOC.

Central nervous system infections in the compromised host: a diagnostic approach

The diagnostic approach to the compromised host with CNS infection depends on an analysis of the patient's clinical manifestations of CNS disease, the acuteness or subacuteness of the clinical presentation, and an analysis of the type of immune defect compromising the patient's host defenses. Most patients with CNS infections may be grouped into those with meningeal signs, or those with mass lesions. Other common manifestations of CNS infection include encephalopathy, seizures, or a stroke-like presentation. Most pathogens have a predictable clinical presentation that differs from that of the normal host. CNS Aspergillus infections present either as mass lesions (e.g., brain abscess), or as cerebral infarcts, but rarely as meningitis. Cryptococcus neoformans, in contrast, usually presents as a meningitis but not as a cerebral mass lesion even when cryptococcal elements are present. Aspergillus and Cryptococcus CNS infections are manifestations of impaired host defenses, and rarely occur in immunocompetent hosts. In contrast, the clinical presentation of Nocardia infections in the CNS is the same in normal and compromised hosts, although more frequent in compromised hosts. The acuteness of the clinical presentation coupled with the CNS symptomatology further adds to limit differential diagnostic possibilities. Excluding stroke-like presentations, CNS mass lesions tend to present subacutely or chronically. Meningitis and encephalitis tend to present more acutely, which is of some assistance in limiting differential diagnostic possibilities. The analysis of the type of immune defect predicts the range of possible pathogens likely to be responsible for the patient's CNS signs and symptoms. Patients with diseases and disorders that decrease B-lymphocyte function are particularly susceptible to meningitis caused by encapsulated bacterial pathogens. The presentation of bacterial meningitis is essentially the same in normal and compromised hosts with impaired B-lymphocyte immunity. Compromised hosts with impaired T-lymphocyte or macrophage function are prone to develop CNS infections caused by intracellular pathogens. The most common intracellular pathogens are the fungi, particularly Aspergillus, other bacteria (e.g., Nocardia), viruses (i.e., HSV, JC, CMV, HHV-6), and parasites (e.g., T. gondii). The clinical syndromic approach is most accurate when combining the rapidity of clinical presentation and the expression of CNS infection with the defect in host defenses. The presence of extra-CNS sites of involvement also may be helpful in the diagnosis. A patient with impaired cellular immunity with mass lesions in the lungs and brain that have appeared subacutely or chronically should suggest Nocardia or Aspergillus rather than cryptococcosis or toxoplasmosis. Patients with T-lymphocyte defects presenting with meningitis generally have meningitis caused by Listeria or Cryptococcus rather than toxoplasmosis or CMV infection. The disorders that impair host defenses, and the therapeutic modalities used to treat these disorders, may have CNS manifestations that mimic infections of the CNS clinically. Clinicians must be ever vigilant to rule out the mimics of CNS infections caused by noninfectious etiologies. Although the syndromic approach is useful in limiting diagnostic possibilities, a specific diagnosis still is essential in compromised hosts in order to describe effective therapy. Bacterial meningitis, cryptococcal meningitis, and tuberculosis easily are diagnosed accurately from stain, culture, or serology of the CSF. In contrast, patients with CNS mass lesions usually require a tissue biopsy to arrive at a specific etiologic diagnosis. In a compromised host with impaired cellular immunity in which the differential diagnosis of a CNS mass lesion is between TB, lymphoma, and toxoplasmosis, a trial of empiric therapy is warranted. Antitoxoplasmosis therapy may be initiated empirically and usually results in clinical improvement after 2 to 3 weeks of therapy. The nonresponse to antitoxoplasmosis therapy in such a patient would warrant an empiric trial of antituberculous therapy. Lack of response to anti-Toxoplasma and antituberculous therapy should suggest a noninfectious etiology (e.g., CNS lymphoma). Fortunately, most infections in compromised hosts are similar in their clinical presentation to those in the normal host, particularly in the case of meningitis. The compromised host is different than the normal host in the distribution of pathogens, which is determined by the nature of the host defense defect. In compromised hosts, differential diagnostic possibilities are more extensive and the likelihood of noninfectious explanations for CNS symptomatology is greater. (ABSTRACT TRUNCATED)

Lung nodular lesions in heart transplant recipients

To describe the characteristics and etiology of lung nodules after heart transplantation (HT). During a 6-year period 147 patients received HT and 130 survived more than 1 week. Nodular lesions were demonstrated after HT in 13 patients (10%). Median age was 53 years, and all patients were male. Nodules were detected 23 to 158 days after HT (median, 66 days). An etiologic diagnosis was made in all but 1 case: Aspergillus (5), Nocardia-Rhodococcus (4), and cytomegalovirus (CMV) (3). Previous severe infection was present in 50% of the patients and rejection in 33% (75% with nocardiosis). Initially all patients with Nocardia but only 1 patient with aspergillosis were asymptomatic. The most common symptoms were fever (67%) and cough (50%). Central nervous system (CNS) involvement appeared in only one Aspergillus-infected patient. An average of 1.8 diagnostic procedures per patient were performed. Median time to establish a diagnosis was 8 days (0 to 24). Median hospital stay was 36 days and reached 60 in patients with Aspergillus. No patient died, although aspergillosis, which must be suspected in the presence of dyspnea, pleuritic pain, and CNS symptoms, caused the highest morbidity. Overall diagnostic yield was 60% for transtracheal aspiration, 70% for bronchoalveolar lavage, and 75% for transthoracic aspiration. Ten percent of HT patients developed lung nodules that were mainly caused by Aspergillus, Nocardia, and CMV. The time of appearance and some clinical manifestations may suggest the etiology and may help in the empirical treatment.

Nocardiosis after bone marrow transplantation: a retrospective study

To evaluate the spectrum of nocardiosis after marrow transplantation, we reviewed the medical records of 27 patients with nocardiosis who were treated at three centers, and we reviewed the findings of three cases reported in the literature. Nocardial involvement was defined as invasive nocardiosis (n = 25), colonization (n = 4), or contamination (n = 1). The median time to the diagnosis of nocardiosis after marrow transplantation was 210 days. Nocardia asteroides complex accounted for 96% of isolates. All 25 invasive infections occurred in allogeneic marrow recipients. Ten (40%) of 25 patients with invasive nocardiosis were receiving double-strength oral trimethoprimsulfamethoxazole twice weekly as prophylaxis for Pneumocystis carinii pneumonia. Treatment regimens for nocardiosis included sulfonamides; synergistic agents were also often added. The overall survival rate at 6 years was 34%; survival from the infection itself was 84%. Two of four nocardiosis-related deaths also involved other pathogens. The incidence of nocardiosis among allogeneic marrow recipients averaged 0.3% over 25 years. We conclude that nocardiosis is a rare infection that occurs later after marrow transplantation than other infections and that is marginally associated with increased mortality among long-term survivors of allogeneic marrow transplantation.

Investigation of a pseudo-outbreak of Nocardia asteroides infection by pulsed-field gel electrophoresis and randomly amplified polymorphic DNA PCR

Molecular strain typing by pulsed-field gel electrophoresis and by randomly amplified polymorphic DNA analysis was used to investigate a cluster of four Nocardia asteroides isolates associated with the BACTEC 460 TB system. An instrument motor drive misalignment resulted in inadequate needle sterilization and cross-contamination of BACTEC vials. This pseudo-outbreak illustrates the importance of proper BACTEC 460 needle sterilization and maintenance and confirms the usefulness of molecular typing methods for epidemiologic investigations.

Transmission of nocardiosis and molecular typing of Nocardia species: a short review

Nocardia species are ubiquitous in the environment and may be found in the soil. They are generally responsible for sporadic pulmonary diseases acquired by inhalation of spores, with secondary localizations in the central nervous system and subcutaneous tissues. There is no absolute evidence for person to person transmission. Presumptive outbreaks of nocardiosis were observed in immunocompromised patients, more frequently in kidney transplant patients than in cardiac transplant patients. Nocardia spp., being present in dust particles, closure and disinfection of the transplantation unit with formaldehyde arrested the sequence of cases of nocardiosis. The original sources of the Nocardia sp. remain doubtful. Other possible sources of contamination are other patients, medical staff and the hospital environment. The first studies of Nocardia spp. typing were based on the detection of extracellular antigens, on the susceptibility of actinomycete strains to killer yeasts, and on the biochemical profiles with fluorogenic substrate. The use of molecular typing techniques have given very promising results. Analysis of plasmid profiles is an interesting way to compare the identity of isolates, although the reliability of this method depends of the presence of plasmids in the isolates. Other typing methods, including analysis of restriction length fragment polymorphism of total DNA, ribosomal DNA fingerprinting, require further investigations to evaluate their discriminating power or to be easily interpretable, whereas a random amplified polymorphic DNA (RAPD) assay was successful for epidemiological purposes. Progress in epidemiological analysis of cases of nocardiosis will be consistent when an improved diagnosis of this infection (molecular and serological diagnosis) will be available, when the genetic diversity of Nocardia spp. isolates will be better known, and when molecular typing, that hold promise in complementing investigations of outbreak of these infections, will be systematically performed when an abnormal increase of cases of nocardiosis in a population with risk factors is observed.

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.

A case of testicular nocardiosis and literature review

A case of epididymo-orchitis due to Nocardia asteroides in a liver transplant recipient is reported. Nocardiosis is an extremely rare cause of epididymo-orchitis. Four other cases published in the English language medical literature are reviewed. All patients were immunocompromised, and other organs were affected simultaneously. Clinically the infection presented as a painful enlargement of the testicle with few inflammatory signs. Mortality was high (3/5), and in the two survivors long-term sulfonamide therapy was combined with orchiectomy. Nocardiosis should be considered in the diagnosis of epididymo-orchitis in the immunocompromised host.

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.

Epidemiology, bacteriology and control of an outbreak of Nocardia asteroides infection on a liver unit

An outbreak of Nocardia asteroides infection affecting seven patients is described. Over a 5-week period, five patients with liver disease admitted to a ward developed clinical and laboratory evidence of nocardiosis, and two further cases were diagnosed 3 and 5 months later. Three out of the five patients who received specific antimicrobial therapy responded to treatment; in three patients nocardia infection was considered to have contributed to death. In six out of the seven patients, nocardiosis followed immunosuppression. A common-source outbreak was considered to be responsible for infection in the first five patients. In two patients, presentation of infection 5 and 7 months after the first case may have been due to prolonged colonization or subclinical infection with Nocardia. Biotyping of the seven isolates using a fluorogenic biochemical method identified three distinct strains of N. asteroides. The most probable source of Nocardia was contaminated brick and plaster dust arising from building work in an area adjacent to the ward. However, samples of air, dust and water failed to yield N. asteroides. Infection control measures included ward closure followed by thorough cleaning, and formaldehyde fumigation.

L-dopa-responsive movement disorder caused by Nocardia asteroides localized in the brains of mice

Nocardia asteroides can cause infections in the brain of humans and a variety of animals. In mice, invasion of the central nervous system results in specific neurologic signs. Following intravenous injection of various doses of log-phase N. asteroides GUH-2 into female BALB/c mice, localization and growth of nocardial cells within the brains were determined, histopathological sections were prepared, and Nissl substance and tyrosine hydroxylase immunoreactivity were observed. Mice were monitored for the development of neurologic signs, and their responsiveness to L-dopa was determined. It was shown that nocardial cells became localized within specific regions of the brain and then underwent rapid growth followed by a delayed clearance, and there was no inflammatory response at the site of invasion for 24 h. Mice that received a subclinical dose of nocardiae developed specific neurologic signs that emerged following the elimination of nocardial cells from the brain. On the basis of the specific signs, mice could be divided into distinct groups. One group consisted of animals that had a form of hemiparesis that did not respond to L-dopa. They expressed a deviation of the head and a tendency to roll, and when suspended by the tail they would spin rapidly. The second group of mice developed a rhythmic, uncontrolled vertical shake of the head (four to five times per s) tremulous movement, stooped posture, restlessness, and no signs of hemiparesis. The head shakes were temporarily stopped by treatment with L-dopa. Mice that expressed head shakes had a loss of Nissl substance and tyrosine hydroxylase immunoreactivity in the neurons of the substantia nigra and ventral tegmental areas of the brain. Hyaline inclusion bodies that resembled Lewy bodies were found in the neurons of mice with head shake 1 month after infection. Therefore, mice infected with N. asteroides may serve as a model for studying parkinsonian signs and other degenerative diseases involving extrapyramidal and pyramidal systems.

Cutaneous abscesses due to systemic nocardiosis--a case report

We report a patient with systemic nocardiosis who developed cutaneous abscesses following haematogenous spread from a primary infection in the lung. This case is unusual; first in that the organism assumed a granular form on histological section, and secondly that the patient was not immunocompromised, emphasizing the need to consider nocardiosis in any patient with pleuropulmonary infection and cutaneous abscesses.

Nocardia asteroides pericarditis: report of a case and review of the literature

In this report, we describe a patient who had purulent Nocardia asteroides pericarditis. In addition, we identified 13 previously suspected and reported cases of Nocardia pericarditis, but only 5 of these studies reported isolation of Nocardia from cultures of pericardial fluid or pericardium. Analysis of the clinical course of these five patients and our patient revealed the importance of long-term sulfonamide antibiotic therapy in combination with surgical pericardial drainage procedures. In our review, only patients who received antibiotics and underwent pericardiectomy survived. Our case substantiates the excellent penetration of sulfisoxazole into the pericardial fluid, even with oral administration of the drug, and provides evidence in support of aggressive management of Nocardia pericarditis.

Nocardia infection in the acquired immunodeficiency syndrome

A case of Nocardia asteroides pneumonia in a patient with the acquired immunodeficiency syndrome who was intolerant of sulfadiazine is described. On cefuroxime, the patient had a complete resolution of his Nocardia pneumonia. Disk-diffusion and broth microdilution antibiotic susceptibility testing (MIC less than or equal to 2 micrograms/ml) strongly supported the use of cefuroxime as treatment in this patient. Susceptibility testing with newer cephalosporins should be considered for all significant Nocardia isolates.

Disseminated Nocardia asteroides with pustules

A case of disseminated Nocardia asteroides in a renal transplant recipient with cavitary lung lesions and cutaneous pustules is presented. Disseminated nocardiosis is a rare disease that occurs chiefly in the immunocompromised host and usually begins as a pleuropulmonary infection. Disseminated nocardiosis should be included in the differential diagnosis of pustules in immunosuppressed patients.

In vitro susceptibilities of Nocardia species to newer antimicrobial agents

The in vitro activities of various quinolones, two newer cephalosporins, and imipenem against 23 strains of Nocardia asteroides, 4 strains of Nocardia brasiliensis, and 4 strains of Nocardia caviae were determined by an agar dilution method. PD-117558, a newer carboxyquinolone, and imipenem were the most active agents tested, inhibiting 90% of N. asteroides isolates at an MIC of 2 micrograms/ml. Of the 23 strains of N. asteroides, 15 were susceptible to cefpirome and 10 were susceptible to ciprofloxacin. The N. brasiliensis and N. caviae strains were very susceptible to PD-117558 (MIC, less than or equal to 1 microgram/ml), moderately susceptible to ciprofloxacin, and resistant to most of the other tested drugs.

Peritonsillar abscess caused by Nocardia asteroides

A 22-year-old man with recurrent pharyngitis developed a peritonsillar abscess from which aspirated material yielded a pure culture of Nocardia asteroides. It is likely that the organism was introduced iatrogenically during a prior tonsillar incision. Although unusual, Nocardia species should be considered and microbiological specimens should be handled appropriately in pharyngeal abscesses that respond poorly to conventional therapy.

Nocardial osteomyelitis: a case report and review of the literature

The occurrence of human nocardiosis is increasing in both immunocompetent as well as immunosuppressed patients. A 63-yr-old male construction worker presented with complaints of left hip pain and rapidly enlarging masses on his left neck and chest. He had been treated for a pneumonia of unknown etiology 3 mo prior to admission. A debridement of the left femur was performed and the curetted material was positive for Nocardia asteroides. Osteomyelitis due to the hematogenous spread of Nocardia asteroides is rare, but will undoubtedly be seen with increasing frequency. The literature, as well as 11 reported cases of the hematogenous spread of this organism, are reviewed.

Nocardia

N asteroides is an aerobic, gram-positive, partially acid-fast, branching rod. Cell-mediated immunity via both macrophage activation and direct cytotoxicity represents the main host defense. While clinical infection most commonly occurs in immunocompromised hosts, Nocardia can infect and exist as a saprophyte in normal hosts. Diligence on the part of the treating physician is necessary to confirm the diagnosis. A combination of trimethoprim and sulfamethoxazole is the mainstay of treatment. With an aggressive approach to diagnosis and therapy, the prognosis in patients with nocardiosis appears to be dependent on their underlying disease process.

Nocardia infection in splenectomized patients: case reports and a review of the literature

Opportunistic infections are increasingly becoming a problem in cancer patients amongst whom infection with Nocardia species is particularly difficult to detect due to the capricious natural history of the disease. Three cases of Nocardia infection in patients who had undergone splenectomy for haematological malignancy are presented. These cases illustrate the diverse mode of presentation, the natural history and the difficulties in early and accurate diagnosis of Nocardia infection. Despite the difficulties in arriving at the correct diagnosis, these cases highlight the importance of early institution of appropriate antibiotic therapy. Antibiotics should be given in adequate doses to control the initial infection and be maintained for a prolonged period to prevent relapses.

Nocardia epididymo-orchitis in an immunosuppressed patient

The immunocompromised patient after organ transplantation is susceptible to unusual and life-threatening infections. We report a case of epididymitis that evolved into testicular nocardiosis after cardiac transplantation. An awareness of the potential for these infections and early diagnosis may prevent extensive morbidity in the post-transplantation patient.

Nocardia asteroides osteomyelitis

Nocardia asteroides osteomyelitis has previously been described only in acutely ill patients. It may occur as an isolated event or part of the disease spectrum of disseminated nocardiosis. An 84 year old immune competent man with N. asteroides right tibial osteomyelitis had an unusual presentation, presumed mechanism of disease and outcome. His course affords an opportunity to review the literature on N. asteroides osteomyelitis and to discuss the unique features of his case.

Actinomycosis and nocardiosis. A morphologic study of 17 cases

Actinomycosis and nocardiosis are bacterial infectious diseases with distinct morphologic features, that can be diagnosed in tissue sections. The clinico-pathologic features of 17 cases are reported with emphasis on their histopathologic diagnosis by using a simple combination of common tissue stains. Actinomycosis was frequently observed as a secondary and localized infection often with lung involvement, especially in residual cavities or bronchiectasis; in these cases numerous actinomycotic granules and only occasionally individual bacterial filaments within the suppurative foci and/or granulomas with suppurative centers were identified. Nocardiosis was observed as an opportunistic infection in the three cases studied; in these, isolated filaments of acid-fast and Gram-positive bacteria were observed. The morphologic features and the differential diagnosis in tissue sections of both infections are discussed with emphasis on their identification by the general pathologist in the routine material.

Nocardiosis in the community hospital. Report of three cases

Nocardiosis is an infectious disease that occurs in both normal and immunocompromised hosts. In North America, the most common presentation is that of primary subacute pneumonia. In Central and South America, primary cutaneous infections are more common. The diagnosis is often missed because of contamination of cultures and the need to culture specimens for extended periods. Because of this difficulty in diagnosis, the incidence of nocardiosis may actually be higher than what published data reveal. Incision and drainage of abscesses and extended drug therapy (eg, with sulfonamides) are the cornerstones of treatment.