Nocardiosis after bone marrow transplantation: a retrospective study

Nocardia pseudobrasiliensis as an emerging cause of opportunistic infection after allogeneic hematopoietic stem cell transplantation

We report the case of a 55-year-old man who exhibited a nodular pneumonia 4 months after an allogeneic hematopoietic stem cell transplantation. Culture of the bronchoalveolar lavage fluid revealed Nocardia pseudobrasiliensis. This recently described carbapenem-resistant species should be included in the differential diagnosis of fungal infection in this setting.

Nocardiosis at the turn of the century

Nocardia species is an uncommon pathogen that affects both immunosuppressed and immunocompetent patients. The clinical and microbiologic spectrum of nocardiosis has changed recently due to the widespread use of cotrimoxazole prophylaxis, the emergence of new types of immunosuppressed patients, and the improved identification of isolates using molecular techniques. Nocardia asteroides was traditionally considered the predominant organism, and prophylaxis with cotrimoxazole was considered almost universally protective. We conducted the current study to determine the incidence of nocardiosis and its microbiologic and clinical characteristics in a general hospital over the last 12 years. We reviewed the clinical records of all patients in whom Nocardia species was isolated from clinical specimens between 1995 and 2006. Nocardia isolates were identified by standard procedures and by 5' end 16S rRNA gene polymerase chain reaction (PCR) and sequencing. Susceptibility to cotrimoxazole, minocycline, imipenem, linezolid, and amikacin was determined by the broth microdilution method following the guidelines of the Clinical and Laboratory Standards Institute.The incidence of Nocardia infections did not increase significantly during the study period (0.39/100,000 inhabitants in 1995-1998 and 0.55/100,000 inhabitants in 2003-2006). Nocardia was recovered from 43 patients. Six were considered to be colonized. The colonizing species were N. farcinica, N. nova, and N. asteroides. All colonized patients had severe underlying pulmonary conditions and were treated with antimicrobials (6 patients) or corticosteroids (4 patients). Invasive nocardiosis was diagnosed in 37 patients (86.5% were men, and their mean age was 55.8 +/- 17.3 yr). The most common underlying condition in our institution was human immunodeficiency virus (HIV) infection (10 patients; 27%), followed by chronic obstructive pulmonary disease (8 patients; 21.6%), autoimmune diseases (8 patients; 21.6%), solid organ transplantation (7 patients; 18.9%), and cancer (4 patients; 10.8%). The most important risk factor for nocardiosis was corticosteroid administration (23 patients; 62.2%). Nocardiosis affected the lungs in 26 cases (70.3%), the skin in 3 cases (8.1%), and the central nervous system in 2 cases (5.4%). It was disseminated in 5 cases (13.5%) and caused otomastoiditis in 1 (2.7%). The species identified were N. cyriacigeorgica (32.4%), N. farcinica (24.3%), N. otitidiscaviarum (10.8%), N. veterana (8.1%), N. nova (5.4%), N. abscessus (5.4%), N. asiatica (2.7%), N. beijingensis (2.7%), N. brasiliensis (2.7%), N. carnea (2.7%), and Nocardia species (2.7%).Linezolid and amikacin were uniformly active against all the isolates, whereas 29.7% of isolates showed intermediate susceptibility to minocycline (minimum inhibitory concentration = 2 mg/L), 10.8% were resistant to cotrimoxazole, and 5.4% were resistant to imipenem. Nocardiosis occurred while the patients were on cotrimoxazole prophylaxis in 8 cases (21.6%). The strains isolated from these patients were susceptible to cotrimoxazole in 5 cases (62.5%) and resistant in 3 (37.5%). Overall, 13 patients died (35.1%); related mortality was 21.6% (8 patients). We conclude that HIV infection has become the most common underlying condition for invasive nocardiosis in our institution, followed by chronic lung disease. Previous use of corticosteroids was the main risk factor and was present in more than half the patients. New species of Nocardia have been identified, and administration of cotrimoxazole prophylaxis should no longer be considered highly reliable protection against nocardiosis. Larger studies of nocardiosis are required to better identify risk factors associated with mortality, and alternative and more effective methods of prevention must be developed.

Nocardiosis in adult-onset Still's disease and vasculitis syndrome

Four cases of nocardiosis in patients with adult-onset Still disease and vasculitis syndrome are presented. Three patients developed lung abscesses and 1 case developed a brain abscess. All were treated with high-dose corticosteroids, and 3 were given cyclosporine when they developed nocardiosis. All patients were successfully treated with antibiotics; cyclosporine was discontinued in 2 cases. These cases indicate that systemic nocardiosis can develop in patients with various rheumatologic diseases who are treated with corticosteroid and immunosuppressive drugs such as cyclosporine.

Nocardia exalbida brain abscess in a patient with follicular lymphoma

Nocardial brain abscess is a rare but severe complication in patients with malignancy. Nocardia exalbida was isolated in Japan and characterized within the genus Nocardia. We present the first report of N. exalbida brain abscess in a 63-year-old male patient with follicular lymphoma. He developed abnormal neurological findings during follicular lymphoma treatment, brain CT revealed ring-enhancing, multiloculated lesions, and N. exalbida was detected by aspiration of the lesion. He was successfully treated with trimethoprime-sulfamethoxazole (TMP-SMX) and meropenem without craniotomy or repeat aspirations. It should be noted that such an infection can occur in patients treated with conventional chemotherapy against malignant lymphoma.

Frequent exacerbation of pulmonary nocardiosis during maintenance antibiotic therapies in a hematopoietic stem cell transplant recipient

We describe a rare case of recurrent pulmonary nocardiosis (PN) in a hematopoietic stem cell transplant recipient. The patient developed Nocardia farcinica infection while receiving corticosteroid and cyclosporine for the treatment of bronchiolitis obliterans, probably due to chronic graft-versus-host disease (cGVHD). The patient responded well to the initial treatment with meropenem, but PN recurred 3 times during oral maintenance therapies using different antibiotics, which were chosen on the basis of the results of in vitro susceptibility testing against N farcinica Minocycline, amoxicillin/clavulanate, and levofloxacin were not effective as oral maintenance therapies. Frequent exacerbation of PN was considered to have resulted from the low blood concentration of these antibiotics, and decreased gastrointestinal absorption, probably due to cGVHD, might have been the underlying problem.

[Disseminated nocardiosis in a child with acute lymphoblastic leukemia]

Nocardiosis is a rare infectious disease in children. We report here a disseminated nocardiosis in a child with acute lymphoblastic leukemia. The patient presented prolonged febrile neutropenia and nodular pneumopathy. Based on the amplification of a 16S rDNA, a PCR assay detected Nocardia sp. in the patient's bronchoalveolar lavage (BAL) fluid. Culture of BAL samples yielded Nocardia nova colonies after 2 weeks of incubation. Hepatic, splenic, renal and cerebral localisations were detected on extension checkup. trimethoprime-sulfamethoxazole and amikacine were started given the results of PCR assay, with a good response. Improvement of the patient's general condition led to complete chemotherapy under ciprofloxacine and ceftriaxone treatment, without nocardiosis reactivation. Nocardiosis is a rare complication in children with acute lymphoblastic leukemia. trimethoprime-sulfamethoxazole prophylaxis is widely used to prevent Pneumocystis jiroveci infection in children with haematologic malignancies. As Nocardia species are usually sensible, trimethoprime-sulfamethoxazole could play a role in Nocardia prophylaxis in such population. In our patient, compliance with trimethoprime-sulfamethoxazole had been low. Nocardia species are relatively fastidious growth bacteria and are difficult to isolate with classical bacteriological techniques. Molecular methods are now available, with a good sensitivity and fast results allowing to start an appropriate antibiotherapy before culture results, as early treatment is a major prognosis factor in nocardiosis. Nocardia infection should be suspected in case of nodular pneumopathy in immunocompromised children. An extension checkup should be performed to detect secondary localisations.

CNS aspergillosis: recognition, diagnosis and management

Early diagnosis of CNS aspergillosis requires a high degree of clinical suspicion, because there are no typical clinical symptoms or CSF findings. Clinical features are usually dramatic and tend to progress rapidly. Changes in mental status, hemiparesis and seizures are most common, but other nonspecific neurological features may occur and should always be an indication for neuroradiological examination in high-risk patients, in order to allow early initiation of antifungal therapy. Low density lesions with little or no mass effect and minimal or no contrast enhancement on CT scans that are usually more numerous on MRI and show intermediate signal intensity within high-signal areas on T2-weighted images, may suggest CNS aspergillosis. Cerebral lesions in CNS aspergillosis are often located not only in the cerebral hemispheres but also in the basal ganglia, thalami, corpus callosum and perforator artery territories. There is frequently a lack of contrast enhancement or perifocal oedema, due to the immunosuppressed status of the patient. A definite diagnosis requires brain tissue for histopathological analysis. However, neurosurgery is often not feasible, so that any of the neuroradiological findings mentioned above should raise the suspicion of CNS aspergillosis in immunocompromised patients and lead to early initiation of antifungal therapy. In the past, amphotericin B-based therapy was the treatment of choice for CNS aspergillosis, but this treatment produced negligible effects. Recently, voriconazole has been reported to be more effective than amphotericin B in the treatment of invasive aspergillosis. Response rates of about 35% have been achieved with voriconazole in patients with CNS aspergillosis. Combination therapy with antifungal agents, such as voriconazole plus caspofungin or liposomal amphotericin B, is being investigated in vitro and in animal models, and optimistic results have been observed. A combined medical and neurosurgical treatment should be considered in all patients with this disease.

Risk factors, clinical characteristics, and outcome of Nocardia infection in organ transplant recipients: a matched case-control study

BACKGROUND

Risk factors for Nocardia infection in organ transplant recipients have not been formally assessed in the current era of transplantation.

METHODS

We performed a matched case-control study (1:2 ratio) between January 1995 and December 2005. Control subjects were matched for transplant type and timing. Univariate matched odds ratios were determined and conditional logistic regression was performed to identify independent risk factors. Clinical and microbiological characteristics of all case patients were reviewed.

RESULTS

Among 5126 organ transplant recipients, 35 (0.6%) were identified as having cases of Nocardia infection. The highest frequency was among recipients of lung transplants (18 [3.5%] of 521 patients), followed by recipients of heart (10 [2.5%] of 392), intestinal (2 [1.3%] of 155), kidney (3 [0.2%] of 1717), and liver (2 [0.1%] of 1840) transplants. In a comparison of case patients with 70 matched control subjects, receipt of high-dose steroids (odds ratio, 27; 95% confidence interval, 3.2-235; P=.003) and cytomegalovirus disease (odds ratio, 6.9; 95% confidence interval, 1.02-46; P=.047) in the preceding 6 months and a high median calcineurin inhibitor level in the preceding 30 days (odds ratio, 5.8; 95% confidence interval, 1.5-22; P=.012) were found to be independent risk factors for Nocardia infection. The majority of case patients (27 [77%] of 35) had pulmonary disease only. Seven transplant recipients (20%) had disseminated disease. Nocardia nova was the most common species (found in 17 [49%] of the patients), followed by Nocardia farcinica (9 [28%]), Nocardia asteroides (8 [23%]), and Nocardia brasiliensis (1 [3%]). Of the 35 case patients, 24 (69%) were receiving trimethoprim-sulfamethoxazole for Pneumocystis jirovecii pneumonia prophylaxis. Thirty-one case patients (89%) experienced cure of their Nocardia infection.

CONCLUSIONS

Receipt of high-dose steroids, history of cytomegalovirus disease, and high levels of calcineurin inhibitors are independent risk factors for Nocardia infection in organ transplant recipients. Our study provides insights into the epidemiology of Nocardia infection in the current era, a period in which immunosuppressive and prophylactic regimens have greatly evolved.

Complications pulmonaires précoces des allogreffes de cellules souches hématopoïétiques

INTRODUCTION

Pneumonia is one of the main causes of mortality following allogenic stem cell transplantation, especially in the first months after the transplant has been performed.

STATE OF THE ART

Pneumonia is the most common infection occurring after transplant and the infection with the highest mortality. Following the classical, myeloablative approach to transplant, two thirds of the pneumonias that occur are of infectious origin. Their causes roughly follow the timing of the immune reconstitution, and may depend on the type of transplant, the match between donor and recipient, and, overall, the occurrence of graft-versus-host disease. Most bacterial pneumonias occur during the initial neutropenic phase. The 2nd and 3rd month post transplant are mainly complicated by viral pneumonia, especially respiratory virus and adenovirus pneumonia in deeply immunosuppressed patients. Preemptive and prophylactic strategies have considerably reduced the incidence of cytomegalovirus pneumonia. Pneumonia due to encapsulated bacteria, such as Haemophilus influenzae and Streptococcus pneumoniae, usually considered to be late infections, may actually be observed from the second month post-transplant.

PERSPECTIVES

The increasing use of reduced-intensity conditioning regimens has modified the time course of the main adverse events following transplantation, including the timing of the infectious pneumonias. The pneumonias that are specifically related to allogenic transplant are idiopathic interstitial pneumonia, bronchiolitis obliterans, and bronchiolitis obliterans organizing pneumonia, which are all considered to be pulmonary manifestations of graft-versus-host disease, and treated as such. Prophylaxis for many of these infectious pneumonias (i.e., P jiroveci, S pneumoniae, toxoplasmosis) are well standardized.

CONCLUSIONS

Much remains to be done to decrease the incidence of pneumonia in these patients and to understand their mechanisms.

Disseminated nocardiosis due to unusual species: two case reports

Pulmonary nocardiosis is the major clinical manifestation of human nocardiosis and disseminated infection can be seen in immunocompromised patients. N. asteroides is the predominant pathogen associated with disseminated diseases. We report 2 cases of pulmonary nocardiosis admitted with disseminated infection, caused by rare species of Nocardia: Nocardia transvalensis and Nocardia cyriacigeorgica.

Clinical and laboratory features of the Nocardia spp. based on current molecular taxonomy

The recent explosion of newly described species of Nocardia results from the impact in the last decade of newer molecular technology, including PCR restriction enzyme analysis and 16S rRNA sequencing. These molecular techniques have revolutionized the identification of the nocardiae by providing rapid and accurate identification of recognized nocardiae and, at the same time, revealing new species and a number of yet-to-be-described species. There are currently more than 30 species of nocardiae of human clinical significance, with the majority of isolates being N. nova complex, N. abscessus, N. transvalensis complex, N. farcinica, N. asteroides type VI (N. cyriacigeorgica), and N. brasiliensis. These species cause a wide variety of diseases and have variable drug susceptibilities. Accurate identification often requires referral to a reference laboratory with molecular capabilities, as many newer species are genetically distinct from established species yet have few or no distinguishing phenotypic characteristics. Correct identification is important in deciding the clinical relevance of a species and in the clinical management and treatment of patients with nocardial disease. This review characterizes the currently known pathogenic species of Nocardia, including clinical disease, drug susceptibility, and methods of identification.

Bacterial and Mycobacterial Pneumonia in Transplant Recipients

Bacteria and myobacteria are important pulmonary pathogens in transplant recipients and are the focus of this article. Although considerable overlap exists, there are significant differences in the epidemiology and clinical presentation of these organisms in solid organ transplant (SOT) and hematopoietic stem cell transplant (HSCT) recipients. The first section of this article focuses on infections in SOT recipients (predominantly heart, liver, lung, and kidney transplant recipients), and the latter addresses these infections in HSCT recipients.

Nocardia asteroides brain abscesses and meningitis in an immunocompromized 10-year-old child

Nocardiosis is an uncommon pediatric infection. We describe the successful treatment of Nocardia brain abscesses and meningitis in an immunocompromized boy with a history of both liver and bone marrow transplants.

Nocardiosis in persons with human immunodeficiency virus infection, transplant recipients, and large, geographically defined populations

To quantify the risk of nocardiosis in various populations, I systematically reviewed articles published between 1966 and 2004. The incidence of nocardiosis in 3 large, geographically defined populations ranged from 0.35 to 0.4 cases per 10(5) persons year. In contrast, the incidence of nocardiosis among people with human immunodeficiency virus (HIV) infection or acquired immunodeficiency syndrome (AIDS) in 1 study was 53 nocardiosis cases per 10(5) persons x year, approximately 140 times greater than that in the geographically defined populations. The frequency of nocardiosis cases in 4 populations of HIV-infected people averaged 608 cases per 10(5) persons. The incidence of nocardiosis in bone marrow-transplant recipients at 1 hospital was 128 cases per 10(5) persons x year, an incidence approximately 340 times greater than that in the geographically defined populations and in the same range as in HIV-infected people. The frequency of nocardiosis in 21 series of cases in recipients of a variety of transplanted organs averaged 1122 cases per 10(5) persons. These estimated incidence rates are imprecise because they were not collected through prospective surveillance systems, but the estimates for the 3 groups were internally consistent and provide useful information for clinicians.

Secular trends of nocardia infection over 15 years in a tertiary care hospital

AIMS

To assess the incidence of nocardia infection over 15 years in a tertiary care hospital.

METHODS

Over a 15 year period, Nocardia spp were isolated from 20 patients hospitalised at the Geneva University Hospitals, Switzerland.

RESULTS

Sixteen patients had one or more underlying conditions. The median time between symptom onset and diagnosis was 30 days. The most common initial unconfirmed diagnosis was pulmonary tuberculosis (four). The lung was involved in 16 cases, followed by the central nervous system (two) and skin (two); one patient had disseminated infection. The most common species identified was N asteroides. In vitro susceptibility testing was performed on 14 of 20 strains. All strains were susceptible to imipenem and amikacin. Initial treatment with trimethoprim/sulfamethoxazole (TMP/SMX) was started in 14 patients, although five patients had to be switched to another treatment because of side effects or lack of efficacy. A cure was observed in 15 patients, death in three, and relapse or complications in two.

CONCLUSIONS

Nocardiosis can become a severe infection and mainly affects profoundly immunocompromised patients. Differential diagnosis often delays the time to diagnosis, which worsens the outcome. New diagnostic tools, such as the polymerase chain reaction, could provide more rapid and reliable results. TMT/SMX was the most commonly prescribed treatment, but needed to be changed for another treatment because of side effects or lack of efficacy in a considerable proportion of patients. Imipenem should be used as an alternative treatment for severely ill patients, and the sulfa combination for less severe infections.

Pulmonary nocardiosis in a patient with CML relapse undergoing imatinib therapy after bone marrow transplantation

We describe a case of pulmonary nocardiosis in a female patient with graft-versus-host disease (GVHD) underwent therapy with imatinib mesylate for a relapse of chronic myeloid leukemia (CML) after allogeneic bone marrow transplantation (BMT). The patient developed chronic GVHD 8 months after the use of imatinib and was on corticosteroid therapy. Three months after the development of chronic GVHD, she acquired pulmonary nocardiosis and a computed tomography (CT) scan of the chest showed multiple nodular lesions with cavitations over both lungs. She was successfully treated with single-agent trimethoprim-sulfamethoxazole (TMP/SMX) and the infection did not recur. Our case indicated that pulmonary nocardiosis could occur in patients with GVHD undergoing imatinib and corticosteroid therapy and might be treated by single-agent TMP/SMX.

Pyothorax caused by Nocardia otitidiscaviarum in a patient with rheumatoid vasculitis

We report a case of pyothorax caused by Nocardia (N.) otitidiscaviarum infection in a 69-year-old man with rheumatoid vasculitis, who was regularly treated with prednisolone in our hospital. Initially, the patient responded poorly to intravenous imipenem/cilastatin (IPM/CS), minocyclin (MINO), and oral trimethoprim-sulfamethoxazole (TMP-SMX), but later improved after treatment with levofloxacin (LVFX) and gentamicin sulfate (GM) according to in vitro susceptibility tests. To our knowledge, this is the first description of pyothorax caused by N. otitidiscaviarum infection. It is a rare disease, but recognition of the disease in immunocompromised patients and the prompt initiation of appropriate treatments based on isolation of the pathogen and susceptibility testing can lead to a successful outcome.

Nocardiosis: a review

Infections caused by Nocardia species are infrequent but challenging to clinicians. They cause a wide variety of diseases in both normal and immunocompromised patients. In recent years, the number of case reports has been increasing, and this can be attributed to the improvements in diagnostic capabilities and the higher clinical index of suspicion accompanying the increased prevalence of immunosuppressed patients. The treatment of nocardiosis also requires expertise. This report reviews the epidemiology, physiopathology, clinical manifestations, diagnosis and treatment of this aerobic bacterial disease.

Evaluation of RIDOM, MicroSeq, and Genbank services in the molecular identification of Nocardia species

The molecular identification of Nocardia species, when compared to phenotypic identification, has two primary advantages: rapid turn-around time and improved accuracy. The information content in the 5'-end of the 16S ribosomal RNA gene is sufficient for identification of most bacterial species. An evaluation was performed to demonstrate the quality of results provided by two specialized databases (RIDOM and MicroSeq 500 versions 1.1 and 1.4.3, library version 500-0125, respectively) and the more general GenBank database. In addition, these results were compared with phenotypic identifications. Partial 5'-16S rDNA sequences from 64 culture collection strains (DSM, CIP, JCM, and ATCC) were derived, in duplicate, independently in two laboratories. Furthermore, the sequences and the conventional identification results of 91 clinical Nocardia isolates were determined. With the exception of N. soli and N. cummidelens, all Nocardia type strains were distinguishable using 5'-16S rDNA sequencing. Assuming a normal distribution for the pairwise distances of all unique Nocardia sequences and choosing a reporting criterion of > or = 99.12% similarity for a "distinct species", a statistical error probability of 1.0% can be calculated. When the various databases were searched with the clinical isolate sequences RIDOM gave a perfect match in 71.4% of cases whereas MicroSeq yielded a perfect match in only 26.4%. The GenBank service gave a 100% similarity in 59.3% but in 70.4% of these cases the results obtained were not exclusive for a single Nocardia species. Conventional methods gave a correct identification in 59 cases, although most recent taxonomic changes were not taken into account. The RIDOM service (http://www.ridom-rdna.de/) is in the process of making available a comprehensive and high-quality database for bacterial identification purposes and provides excellent results for the majority of Nocardia isolates.

Nocardia veterana, a new emerging pathogen

Nocardia veterana is a newly described species named after the veteran's hospital where it was first isolated. This initial type strain was not thought to be clinically significant. We describe three cases of pulmonary disease attributable to N. veterana: two cases in patients presenting with multiple pulmonary nodules in a setting of immunocompromise and one case of exacerbation of chronic pulmonary disease. The isolates were susceptible to ampicillin, imipenem, gentamicin, amikacin, and trimethoprim-sulfamethoxazole and had reduced susceptibilities to ceftriaxone, cefotaxime, minocycline, and ciprofloxacin. The MICs of amoxicillin-clavulanate were higher than that of ampicillin alone, and the bacteria produced a beta-lactamase detectable only after induction with clavulanic acid. Phenotypically, the isolates could not be characterized beyond the Nocardia genus level. All three isolates were definitively identified as N. veterana by PCR and sequencing of the 16S rRNA gene. On the basis of their susceptibility and restriction enzyme analysis profiles, our findings indicate that they could potentially be misidentified as N. nova. These cases illustrate the pathogenic potential of this newly described species and emphasize the importance of accurate identification of Nocardia isolates to the species level by integrated use of phenotypic and genotypic methods.

Systemic nocardiosis following allogeneic bone marrow transplantation

Five cases of systemic Nocardia infection were diagnosed among 301 allogeneic bone marrow transplant recipients. A sixth case included in this report received her transplant at another institution. The cumulative annual incidence rate of this infection was 1.75%. All patients had been treated previously for acute graft-versus-host disease (GVHD). At the time of diagnosis of systemic Nocardia infection, a median of 198 (range 148-1121) days after transplantation, all patients had extensive chronic GVHD and were taking 2 to 3 immunosuppressive medications. Prior to diagnosis of Nocardia infection patients had experienced multiple opportunistic infections, including infections with Mycobacterium avium-intracellulare, Pneumocystis carinii, and cytomegalovirus antigenemia. Treatment with trimethoprim-sulfamethoxazole (TMP-SMX), ceftriaxone, or carbapenem antibiotics resulted in a median survival of 219 days from the time of diagnosis and an actuarial 1-year survival of 40%. All patients who received more than 2 weeks of therapy were cured of their infections. Notably, 5/6 patients in this cohort were unable to take TMP-SMX because of myelosuppression. In comparison with randomly selected control patients, the use of pentamidine for prevention of P. carinii infection was associated with a marginal increase in the risk of Nocardia infection. We postulate that the use of TMP-SMX may be of benefit in the prophylaxis of infections other than P. carinii in patients with chronic GVHD.

Infectious complications in patients undergoing unrelated donor bone marrow transplantation: experience from a single institution

OBJECTIVE

To analyze the incidence and characteristics of documented infections in patients with hematologic malignancies undergoing unrelated donor bone marrow transplantation (UD-BMT).

METHODS

We studied the occurrence of infections in 22 patients with hematologic malignancies or severe aplastic anemia who underwent UD-BMT from April 1990 to December 2000. The median age was 26 years (range 13-46). Acyclovir-ganciclovir, co-trimoxazole, fluconazole-nystatin and ciprofloxacin were administered for anti-infectious prophylaxis.

RESULTS

We registered 61 infectious episodes. During the early post-transplant period, there were eight clinically documented infections (CDIs), four cases of fever of unknown origin (FUO), seven cases of bacteremia, two cases of cytomegalovirus (CMV) antigenemia, and one case of CMV disease. In the intermediate period (days 30-100 after BMT), there were nine cases of CMV antigenemia, three bacterial infections, two fungal infections, one case of disseminated toxoplasmosis, and one case of FUO. In the late period (day 100 and later), we documented 13 viral infections, eight bacterial infections, one CDI, and one case of invasive aspergillosis. Infections contributed to death in 10 of 17 patients. Citrobacter bacteremia and sepsis of unknown origin were the main causes of infectious mortality in the early period. Infection was the main cause of death in six of seven patients in the late period.

CONCLUSION

A high incidence of life-threatening infections and infection-related mortality was observed. A high rate of CMV infection in the early period, and death caused by multiresistant Gram-negative microorganisms in the late period, were the main findings in this series.

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.

Infections following hematopoietic stem cell transplantation

Numerous advances have been made in the management of infection in HSCT recipients. With increasing knowledge the authors are able to prevent several serious infections from occurring, and reduce the severity of infections once they occur. Despite these advances, several previously unrecognized pathogens have emerged and pose risks to this population. Ongoing surveillance and reporting of atypical infections are warranted. Transplant and infectious disease clinicians alike must be vigilant to the shifts in infectious syndromes as a consequence of various prophylaxis and preemptive strategies, and be ready to modify empiric strategies to meet the changing microbiologic milieu. As we increase our understanding of the HSCT process, and use the immune system rather than relying on high-dose chemotherapy, the authors are likely to reduce toxicities and improve patient outcomes.

Infections in recipients of blood and marrow transplantation

The approach to infections in blood and marrow transplant (BMT) recipients involves an understanding of clinical infection syndromes and the natural history of individual infections, taken in the context of patterns of immunosuppression after transplantation and mechanisms underlying immune system reconstitution over time. The conditioning regimen used to prepare the host is a major determinant of host tissue injury and may lead to mucositis or diarrhea, facilitating transmucosal origin of bloodstream infections. Infectious risk also differs between autologous and allogeneic grafts as a consequence of ongoing immunosuppression from graft-versus-host disease and its therapy. Post-transplant complications may mimic infectious processes, and multiple infections may occur in one patient at the same time. Thus, the BMT patient with suspected infection should be evaluated in the context of pretransplant exposure history (infectious disease serologies), conditioning regimen, available culture data from nonsterile mucosal surfaces, previous and recent infections, contemporary transplant complications, and the current degree and duration of neutropenia, cellular immunodeficiency, and hypogammaglobulinemia.