Pulmonary tuberculosis in allogeneic hematopoietic stem cell transplantation

Bacterial Pathogens Causing Pneumonia Post Hematopoietic Stem Cell Transplant: The Chronic GVHD Population

Allogeneic stem cell transplantation is a lifesaving treatment for many malignancies. Post-transplant patients may suffer from graft versus host disease in the acute and/or the chronic form(s). Post-transplantation immune deficiency due to a variety of factors is a major cause of morbidity and mortality. Furthermore, immunosuppression can lead to alterations in host factors that predisposes these patients to infections. Although patients who receive stem cell transplant are at an increased risk of opportunistic pathogens, which include fungi and viruses, bacterial infections remain the most common cause of morbidity. Here, we review bacterial pathogens that lead to pneumonias specifically in the chronic GVHD population.

Disseminated Tuberculosis With an Atypical Cutaneous Manifestation in a Hematopoietic Cell Transplant Patient in the Early Posttransplant Period: Case Report and Review of the Literature

We describe an unusual case of posttransplant tuberculosis reactivation in a man who underwent allogeneic hematopoietic cell transplant. Concomitant with disseminated adenovirus infection, reactivation of tuberculosis manifested as disseminated, nonfollicular pustules on day +49. Skin biopsy was obtained on day +50. Initial histopathologic evaluation did not suggest mycobacterial infection, but tissue stain showed acid-fast organisms, which were subsequently identified as Mycobacterium tuberculosis. Shortly after the cutaneous presentation of tuberculosis, the patient died on day +52. Our case is among a paucity of reports describing tuberculosis reactivation in hematopoietic cell transplant patients in the early posttransplant period. It highlights the difficulty of diagnosing contemporaneous systemic infections, and it presents a rare and atypical cutaneous manifestation of tuberculosis in a hematopoietic cell transplant patient. Our case and review of the literature emphasize the need for further research to elucidate risk factors associated with early posttransplant reactivation of tuberculosis, and the importance of remaining vigilant for active tuberculosis in hematopoietic cell transplant patients with epidemiologic risk factors.

Study of clinical characteristics, risk factors and outcomes for tuberculosis post allogeneic stem cell transplant: never count it out

BACKGROUND

Allogeneic stem cell transplant (AlloSCT) recipients remain at a higher risk of developing tuberculosis (TB), especially in endemic populations. We conducted a retrospective study to identify the incidence, clinical presentation, and risk factors for active TB among our alloSCT recipients.

METHODS

Records of all patients transplanted between 1 January 2012 and 31 July 2020 were reviewed. Patients were followed up for outcome until 30 September 2020. None of the patients received prophylactic anti-tubercular drugs. Proven diagnosis of active TB was considered if Mycobacterium tuberculosis (MTB) was cultured from clinical samples or acid-fast bacilli (AFB) or MTB demonstrated on Ziehl-Neelsen (ZN) staining or histopathology or XPERT MTB, while probable diagnosis of TB was considered if histopathology findings were suggestive of caseation necrosis/epithelioid cell granulomas without any evidence of malignancy or lymphocyte rich exudative effusions (pleural/pericardial) without an alternative cause.

RESULTS

Among 381 alloSCT recipients, 15 patients (3.9%) developed TB at median of 246 (74-279) days post AlloSCT, after being symptomatic for a median of 22 (7-60) days, amounting to a cumulative incidence of 4.9%. All patients were started on four-drug anti tubercular therapy, ATT [Rifampicin, Isoniazid, Ethambutol, Pyrazinamide (RHEZ)], of which five patients developed hepatotoxicity at a median of 12 days after start of ATT, leading to drug modification. At last follow up, TB was cured in 13 (86.67%) patients, one succumbed to disease relapse, while others are still on treatment. Age ⩾ 30 years, immunosuppression for graft versus host disease (GvHD) > 6 months, prior use of tyrosine kinase inhibitors (TKI) and chronic GvHD on univariate analysis and immunosuppression for GvHD > 6 months on multivariate analysis were found to be associated with development of TB.

CONCLUSION

A high index of suspicion with timely workup and treatment of TB is the key in AlloSCT recipients, especially in endemic TB populations.

High prevalence of latent tuberculosis in hematopoietic stem cell transplant recipients: A First Report

TB is an increasing health problem, and patients undergoing HSCT are more prone to develop tuberculosis. The aim of our study was to evaluate prevalence of latent tuberculosis in HSCT recipients. In this study, 84 patients (2 months to 18 years) who were candidates for HSCT at the referral hospital of Tehran Children's Medical Center were enrolled. The TST and the QFT-GIT test were performed in all 84 patients, simultaneously. LTBI was considered when one of the tests was positive. Overall, the prevalence of LTBI in HSCT recipients in our study was 12% (10 cases). TST induration ≥5 mm was seen in only three patients (3.5%). Eight patients (9.5%) had a positive result for IGRA test, and 11 of them (13%) had indeterminate QFT-GIT result. The agreement between the TST results (induration size ≥5 mm) and the QFT-GIT results was poor (kappa = 0.14). In conclusion, there was a high rate of discordance between TST and IGRA results with many more positive QFT-GIT tests. However, more studies are needed in this population to determine whether this discordance reflects true infection.

Allo-HSCT recipients with invasive fungal disease and ongoing immunosuppression have a high risk for developing tuberculosis

Patients underwent allogeneic hematopoietic stem cell transplantation (allo-HSCT) are at high risk of acquiring tuberculosis (TB) due to a status of immunosuppression. We conducted a nested case control study to investigate the incidence and risk factors for TB after allo-HSCT. Between 2012 and 2017, 730 consecutive allo-HSCT recipients were enrolled, and 14 patients (1.92%) were diagnosed with TB. Relatively, 54 allo-HSCT recipients were selected as control. Patients who suffered TB had a significantly higher 3-year non-relapse mortality rate than the control group (30.36% vs 5.39%, P < 0.01). In multivariate analysis, invasive fungal disease (HR 4.87, 95% CI 1.39–17.09), treatment with a relatively high dose of prednisone (HR 10.34, 95% CI 1.12–95.47) and treatment with tacrolimus (HR 4.79, 95% CI 1.18–19.44) were identified independent risk factors for TB occurrence post allo-HSCT (P < 0.05). Meanwhile, donor type, dose and type of anti-thymocyte globulin (ATG) administrated, as well as treatment intensity, did not alter the incidence of TB. Therefore, allo-HSCT recipients with unexplained fever, especially those who suffer from invasive fungal disease and ongoing immunosuppression with a relatively high dose of prednisone or tacrolimus, are at a high-risk of developing active TB. Closely Monitoring TB occurrence, making a timely diagnosis and administering the proper treatment may be beneficial to those high-risk patients.

Prevalence of active tuberculosis infection in transplant recipients: A systematic review and meta-analysis

INTRODUCTION

Tuberculosis (TB) is considered as a serious complication of organ transplant; therefore, the detection and appropriate treatment of active TB infection is highly recommended for the reduction of mortality in the future. The aim of this review was to conduct a systematic review and meta-analysis assessing the prevalence of active TB infection in transplant recipients (TRs).

MATERIAL AND METHODS

Electronic databases, including MEDLINE (via PubMed), SCOPUS and Web of Science were searched up to December 24, 2017. The prevalence of active TB was estimated using the random effects meta-analysis. Heterogeneity was evaluated by subgroup analysis. Data were analyzed by STATA version 14.

RESULTS

The pooled prevalence of post-transplant active TB was estimated 3% [95% CI: 2-3]. The pooled prevalence of active TB in different transplant forms was as follows: renal,3% [95% CI: 2-4]; stem cell transplant (SCT), 1% [95% CI: 0-3]; lung, 4% [95% CI: 2-6]; heart, 3% [95% CI: 2-4]; liver, 1% [95% CI: 1], and hematopoietic stem cell transplant (HSCT), 2% [95% CI: 1-3]. The prevalence of different clinical presentations of TB was as follows: pulmonary TB (59%; 95% CI: 54-65), extra pulmonary TB (27%; 95% CI: 21-33), disseminated TB (15%; 95% CI: 12-19) and miliary TB (8%; 95% CI: 4-13). The pooled prevalence of different diagnostic tests was as follows: chest X-ray, 57% [95% CI, 46-67]; culture, 56% [95% CI, 45-68]; smear, 49% [95% CI, 40-58]; PCR, 43% [95% CI, 40-58]; histology, 26% [95% CI, 20-32], and tuberculin skin test, 19% [95% CI, 10-28].

CONCLUSION

A high suspicion level for TB, the early diagnosis and the prompt initiation of therapy could increase the survival rates among SOT patients. Overall, renal and lung TRs appear to have a higher predisposition for acquiring TB than other type of recipients. Monitoring of the high-risk recipients, prompt diagnosis, and appropriate treatment are required to manage TB infection among TRs especially in endemic areas.

Tuberculosis and Transplantation

Mycobacterium tuberculosis is a major opportunistic pathogen in transplant recipients. Compared to that in the general population, the frequency of tuberculosis (TB) is 10 to 40 times higher in hematopoietic stem cell transplant (HSCT) recipients and 20 to 74 times higher in solid-organ transplant (SOT) recipients. Transplant recipients with TB are also more likely to develop disseminated disease, have longer time to definitive diagnosis, require more invasive diagnostic procedures, and experience greater anti-TB treatment-related toxicity than the general population. Specific risk factors for TB in SOT recipients include previous exposure to M. tuberculosis (positive tuberculin skin tests and/or residual TB lesions in pretransplant chest X ray) and the intensity of immunosuppression (use of antilymphocyte antibodies, type of basal immunosuppression, and intensification of immunosuppressive therapy for allograft rejection). Risk factors in HSCT recipients are allogeneic transplantation from an unrelated donor; chronic graft-versus-host disease treated with corticosteroids; unrelated or mismatched allograft; pretransplant conditioning using total body irradiation, busulfan, or cyclophosphamide; and type and stage of primary hematological disorder. Transplant recipients with evidence of prior exposure to M. tuberculosis should receive treatment appropriate for latent TB infection. Optimal management of active TB disease is particularly challenging due to significant drug interactions between the anti-TB agents and the immunosuppressive therapy. In this chapter, we address the epidemiology, clinical presentation, diagnostic considerations, and management strategies for TB in SOT and HSCT recipients.

The demanding attention of tuberculosis in allogeneic hematopoietic stem cell transplantation recipients: High incidence compared with general population

BACKGROUND

The risk of developing tuberculosis (TB) in allogeneic hematopoietic stem cell transplantation (HSCT) recipients is expected to be relatively high in an intermediate TB burden country. This single-center retrospective study was conducted to investigate risk factors and the incidence of TB after allogeneic HSCT.

METHODS

From January 2004 to March 2011, 845 adult patients were enrolled. Starting April 2009, patients were given isoniazid (INH) prophylaxis based on interferon-γ release assay results. The incidence of TB was analyzed before and after April 2009, and compared it with that of the general population in Korea.

RESULTS

TB was diagnosed in 21 (2.49%) of the 845 allogeneic HSCT patients. The median time to the development of TB was 386 days after transplantation (range, 49-886). Compared with the general population, the standardized incidence ratio of TB was 9.10 (95% CI; 5.59-14.79). Extensive chronic graft-versus-host disease (GVHD) was associated with the development of TB (P = 0.003). Acute GVHD, conditioning regimen with total body irradiation and conditioning intensity were not significantly related. INH prophylaxis did not reduce the incidence of TB (P = 0.548). Among 21 TB patients, one patient had INH prophylaxis.

CONCLUSION

Allogeneic HSCT recipients especially those who suffer from extensive chronic GVHD are at a high risk of developing TB. INH prophylaxis did not statistically change the incidence of TB, however, further well-designed prospective studies are needed.

Reduced incidence of interstitial pneumonitis after allogeneic hematopoietic stem cell transplantation using a modified technique of total body irradiation

Allogeneic hematopoietic stem cell transplantation is a curative-intent treatment for patients with high-risk hematologic diseases. However, interstitial pneumonitis (IP) and other toxicities remain major concerns after total body irradiation (TBI). We have proposed using linear accelerators with rice-bag compensators for intensity modulation (IM-TBI), as an alternative to the traditional cobalt-60 teletherapy with lung-shielding technique (Co-TBI). Patients who received a TBI-based myeloablative conditioning regimen between 1995 and 2014 were recruited consecutively. Before March 2007, TBI was delivered using Co-TBI (n = 181); afterward, TBI was administered using IM-TBI (n = 126). Forty-four patients developed IP; of these cases, 19 were idiopathic. The IP-related mortality rate was 50% in the total IP cohort and 63% in the idiopathic subgroup. The 1-year cumulative incidences of IP and idiopathic IP were 16.5% and 7.4%, respectively; both rates were significantly higher in the Co-TBI group than in the IM-TBI group. Multivariate analysis revealed that Co-TBI was an independent prognostic factor for both total and idiopathic IP. In the acute myeloid leukemia subgroup, patients with different TBI techniques had similar outcomes for both overall and relapse-free survival. In conclusion, IM-TBI is an easy and effective TBI technique that could substantially reduce the complication rate of IP without compromising treatment efficacy.

Attitudes about tuberculosis prevention in the elimination phase: a survey among physicians in Germany

Background

Targeted and stringent measures of tuberculosis prevention are necessary to achieve the goal of tuberculosis elimination in countries of low tuberculosis incidence.

Methods

We ascertained the knowledge about tuberculosis risk factors and stringency of tuberculosis prevention measures by a standardized questionnaire among physicians in Germany involved in the care of individuals from classical risk groups for tuberculosis.

Results

510 physicians responded to the online survey. Among 16 risk factors immunosuppressive therapy, HIV-infection and treatment with TNF-antagonist were thought to be the most important risk factors for the development of tuberculosis in Germany. Exposure to a patient with tuberculosis ranked on the 10^th position. In the event of a positive tuberculin-skin-test or interferon-γ release assay only 50%, 40%, 36% and 25% of physicians found that preventive chemotherapy was indicated for individuals undergoing tumor necrosis factor-antagonist therapy, close contacts of tuberculosis patients, HIV-infected individuals and migrants, respectively.

Conclusions

A remarkably low proportion of individuals with latent infection with Mycobacterium tuberculosis belonging to classical risk groups for tuberculosis are considered candidates for preventive chemotherapy in Germany. Better knowledge about the risk for tuberculosis in different groups and more stringent and targeted preventive interventions will probably be necessary to achieve tuberculosis elimination in Germany.

Infections Caused by Mycobacterium tuberculosis in Recipients of Hematopoietic Stem Cell Transplantation

Mycobacterium tuberculosis (M. tuberculosis) infections are uncommon in recipients of hematopoietic stem cell transplantation. These infections are 10-40 times commoner in recipients of stem cell transplantation than in the general population but they are 10 times less in stem cell transplantation recipients compared to solid organ transplant recipients. The incidence of M. tuberculosis infections in recipients of allogeneic stem cell transplantation ranges between <1 and 16% and varies considerably according to the type of transplant and the geographical location. Approximately 80% of M. tuberculosis infections in stem cell transplant recipients have been reported in patients receiving allografts. Several risk factors predispose to M. tuberculosis infections in recipients of hematopoietic stem cell transplantation and these are related to the underlying medical condition and its treatment, the pre-transplant conditioning therapies in addition to the transplant procedure and its own complications. These infections can develop as early as day 11 and as late as day 3337 post-transplant. The course may become rapidly progressive and the patient may develop life-threatening complications. The diagnosis of M. tuberculosis infections in stem cell transplant recipients is usually made on clinical grounds, cultures obtained from clinical specimens, tissues biopsies in addition to serology and molecular tests. Unfortunately, a definitive diagnosis of M. tuberculosis infections in these patients may occasionally be difficult to be established. However, M. tuberculosis infections in transplant recipients usually respond well to treatment with anti-tuberculosis agents provided the diagnosis is made early. A high index of suspicion should be maintained in recipients of stem cell transplantation living in endemic areas and presenting with compatible clinical and radiological manifestations. High mortality rates are associated with infections caused by multidrug-resistant strains, miliary or disseminated infections, and delayed initiation of therapy. In recipients of hematopoietic stem cell transplantation, isoniazid prophylaxis has specific indications and bacillus Calmette-Guerin vaccination is contraindicated as it may lead to disseminated infection. The finding that M. tuberculosis may maintain long-term intracellular viability in human bone marrow-derived mesenchymal stem cells complicates the development of effective vaccines and strategies to eliminate tuberculosis. However, the introduction of linezolid, cellular immunotherapy, and immunomodulation in addition to autologous mesenchymal stem cell transplantation will ultimately have a positive impact on the overall management of infections caused by M. tuberculosis.

Tuberculosis in hematopoietic stem cell transplant recipients

Literature on tuberculosis (TB) occurring in recipients of Hematopoietic Stem Cell Transplant (HSCT) is scanty even in countries where TB is common. Most reports of TB in HSCT patients were from ASIA, in fact the TB incidence ranging from 0.0014 (USA) to 16% (Pakistan). There are few reports of TB diagnosis during the first two weeks after HSCT; most of cases described in the literature occurred after 90 days of HSCT, and the lung was the organ most involved. The mortality ranged from 0 to 50% and is higher in allogeneic HSCT than in autologous. There is no consensus regarding the screening with tuberculin skin test or QuantiFERON-TB gold, primary prophylaxis for latent TB, and whether the epidemiologic query should be emphasized in developing countries with high prevalence of TB.

Clinical characteristics and outcomes of Mycobacterium tuberculosis disease in adult patients with hematological malignancies

BACKGROUND

Diseases caused by Mycobacterium tuberculosis (TB) among adult patients with hematological malignancies have rarely been investigated.

METHODS

Adult patients with hematological malignancies at National Taiwan University Hospital between 1996 and 2009 were retrospectively reviewed. Patients with positive serology for HIV were excluded. TB disease is diagnosed by positive culture(s) in the presence of compatible symptoms and signs. The demographics, laboratory and, microbiological features, were analyzed in the context of clinical outcomes.

RESULTS

Fifty-three of 2984 patients (1.78%) were diagnosed with TB disease. The estimated incidence was 120 per 100,000 adult patients with hematological malignancies. Patients with acute myeloid leukemia had a significantly higher incidence of TB disease than other subtypes of hematological malignancies (2.87% vs. 1.21%, p = 0.002, odds ratio, 2.40; 95% confidence interval, 1.39-4.41). Thirty-eight patients (72%) with non-disseminated pulmonary TB disease presented typically with mediastinal lymphadenopathy (53%), pleural effusion (47%) and fibrocalcific lesions (43%) on chest imaging. The 15 (28%) patients with extra-pulmonary disease had lower rates of defervescence within 72 h of empirical antimicrobial therapy (13% vs 45%, p = 0.03) and a higher 30-day in-hospital mortality (20% vs. 0%, p = 0.004) compared to those with disease confined to the lungs.

CONCLUSIONS

TB disease is not uncommon among patients with hematological malignancies in Taiwan. Patients who received a diagnosis of extra-pulmonary TB suffered higher mortality than those with pulmonary TB alone. Clinicians should consider TB in the differential diagnoses of prolonged fever in patients with hematological malignancies, particularly in regions of high endemicity.

Two children with differing outcomes after treatment for pulmonary tuberculosis diagnosed after allogeneic hematopoietic stem cell transplantation

Tuberculosis (TB) is a rare infectious complication after hematopoietic stem cell transplantation (HSCT), but may be more significant in areas where the disease is endemic. Here, we present the clinical course of 2 children with acute lymphoblastic leukemia who were diagnosed with pulmonary TB after allogeneic HSCT. Both patients were treated for either probable or possible invasive fungal infection, as well as TB. One patient, diagnosed with TB 3 months after HSCT, showed remittent fever and symptoms that progressed to acute respiratory distress syndrome and death, despite 3 modifications to the anti-TB regimen. In contrast, another patient who was diagnosed with TB 8 months after transplantation, responded well to anti-TB medication and completed 1 year of treatment with resolution of lung lesions. Co-morbid opportunistic infections, profound host immunosuppression early after transplantation, and potential risk of multi-drug resistant-TB may act as major barriers to effective treatment of TB after HSCT despite appropriate anti-TB medication.

Tuberculosis in hematopoietic stem cell transplant patients: case report and review of the literature

The literature describing tuberculosis (TB) in hematopoietic stem cell transplant (HSCT) recipients is scant, even in countries where TB is common. We describe a case of pulmonary TB in a patient who underwent HSCT and review the English language literature on this subject. An extensive PubMed and Ovid search was undertaken for the period January 1980 to March 2009; the search terms used were 'Mycobacterium tuberculosis' or 'tuberculosis', in combination with 'hematopoietic stem cell transplantation' or 'bone marrow transplantation'. The patient in the present case report underwent allogeneic transplantation and developed TB 8 days after his HSCT. The patient had received vaccination against TB in childhood. During the year prior to the HSCT he had had contact with a relative who had pulmonary TB. On day 3 of anti-TB treatment he developed pericarditis. The patient received anti-TB treatment for 6 months without major problems. From the literature review, we found 34 related studies, 25 on the clinical manifestations of TB. Most of the reports were from Asia (48%), and the incidence of TB varied from 0.0014% in the USA to 16% in Pakistan. TB occurred at between +21 and +1410 days post-HSCT (257.2 days the median), and the lung was the organ most frequently involved. Mortality varied from 0% to 50% and was higher in allogeneic HSCT. There is no consensus regarding screening with the tuberculin skin test or primary prophylaxis for latent TB, and further research into this is necessary in developing countries with a high prevalence of TB.

Current status of hematopoietic stem cell transplantation in Taiwan

In Taiwan, hematopoietic SCT (HSCT) has been used to treat patients with hematological diseases since 1983. Since then, more than 2200 patients have undergone HSCT in 15 large hospitals. The disease entities included acute leukemia in 37% of cases, non-Hodgkin's lymphoma in 26%, CML in 10%, multiple myeloma in 7% and severe aplastic anemia in 6%. The conditioning regimens used were mainly myeloablative (84% of cases). Non-myeloablative regimens were fludarabine-based. The average age of allogeneic recipients was at least 10 years older than those in the era before their application. The grafts of all patients were derived from peripheral blood in 85% of cases, BM in 13% and cord blood (CB) in 2%. Forty percent of HSCT patients received autologous grafts, whereas more than 25% of allogeneic HSCT patients received grafts from unrelated donors, and overall, there were more than 200 Taiwan HSCT recipients. Currently, CB has been used successfully in pediatric patients with thalassemia major and also in adult patients with hematological malignancy. After transplantation, there was a relatively lower prevalence of acute GVHD. However, a relatively higher proportion of hepatitis B carriers in the recipients had led to a higher incidence of viral reactivation and clinical hepatitis, which was dramatically decreased following lamivudine prophylaxis. In conclusion, HSCT has been successfully adapted to routine clinical care in Taiwan. Several important findings contributing to the progress of HSCT in the past two decades have also been noticed on this island.

Multiple intracranial tuberculomas mimicking granulocytic sarcomas in acute myeloid leukemia

The diagnosis of incracranial tuberculoma in immune-compromised hosts is often difficult because conventional magnetic resonance (MR) imaging of tuberculoma reveals various findings and neurologic symptoms are not typical. Here, we report a case of a 54-yr old man with multiple intracranial tuberculoma who was treated for acute myeloid leukemia. He complained of right-side paresthesia after the third consolidation chemotherapy without leukemic relapse and fever. MR imaging of the brain showed multiple ring-enhanced lesions in the cerebrum, cerebellar hemisphere, and pons. The lesions appeared to mimic a metastatic tumor or abscess. Cerebrospinal fluid analysis showed no abnormal cells, but the level of adenosine deaminase was elevated (28.8 IU/L, normal 0-8). Stereotactic brain biopsy was performed, but only reactive gliosis was observed. To confirm diagnosis, an open brain biopsy was performed. The histopathology demonstrated chronic granulomatous inflammation with caseous necrosis. Tuberculous-polymerase chain reaction of the biopsy showed a positive result. He was treated with anti-tuberculosis medication and a high dose of steroid. Paresthesia improved, and follow-up brain MR imaging showed the decreased size and numbers of ring-enhanced lesions and improvement of perilesional edema 1 month after treatment. Here, we report on an interesting case of intracranial tuberculoma in acute myeloid leukemia.

Mycobacterium tuberculosis Bacteremia in HIV-negative Patients

BACKGROUND/PURPOSE

Limited information exists about the epidemiologic characteristics of HIV-negative patients with Mycobacterium tuberculosis bacteremia (MTB).

METHODS

We retrospectively surveyed tuberculosis (TB) cases reported at National Taiwan University Hospital between 1997 and 2003. Demographic data, underlying diseases or conditions, clinical, microbiologic and radiologic findings and therapy were collected. Long-term outcome was evaluated at 1 year after initiation of anti-TB agents.

RESULTS

During the study period the incidence of MTB bacteremia in HIV-negative patients and HIV-positive patients were 0.024 and 6.2 per 1000 discharges, respectively (p<0.01). All 11 HIV-negative patients were males and eight (73%) were more than 50 years old. The most common underlying diseases/conditions were immunosuppressive therapy (64%) and heart disease (55%). Fever (80%), lymphopenia (75%) and pulmonary symptoms (58%) were the most common presentations. Ten patients were septic, two had septic shock and two had acute respiratory distress syndrome on admission. The median interval between admission and initiation of therapy for those who were cured was 6 days. Six (55%) died of TB and/or their underlying diseases. Of the six patients who died, the median survival after collection of positive blood culture was 19 days for three treated patients and 7 days for three untreated patients (p=0.01).

CONCLUSION

This case series demonstrates the wide spectrum of the initial presentation of HIV-negative patients with MTB bacteremia. The case fatality rate was high and was likely due to immunocompromised status and no anti-TB treatment prior to death. A high index of suspicion for TB and blood culture for MTB provides an additional simple and noninvasive diagnostic method to detect disseminated TB in endemic areas.

UC blood infection with clinical strains of Mycobacterium tuberculosis: a novel model

BACKGROUND

Use of unrelated cord blood transplantation (UCBT) is increasing, yet high rates of mortality secondary to infection remain a problem. We investigated the utility of using umbilical cord blood (UCB) as a model to study a naive cell population challenged by Mycobacterium tuberculosis.

METHODS

Mononuclear cells were isolated from nine UCB samples and infected with each of four distinct strains of M. tuberculosis. The isolates used were two highly transmissible clinical strains, the virulent laboratory strain H37Rv and a unique strain isolated from only one case (i.e. non-virulent). CFU were assessed at 3 h post-infection (day 0) and at day 7 to generate growth curves. Viability of the mononuclear cells was assessed prior to infection, 3 h post-infection and at days 3, 5 and 7 post-infection. IFN-gamma and TNF-alpha levels were determined at 24 h post-infection.

RESULTS

All three of the virulent strains demonstrated rapid growth in UCB cells that was significantly faster than the growth rate observed for the non-virulent unique isolate. There was no significant decrease in UCB cell viability after the 7-day incubation period regardless of infecting isolate. UCB cells secreted IFN-gamma in response to infection, with no significant difference related to infection with different isolates. However, there was a significant increase in the amount of TNF-alpha elicited following infection with the non-virulent isolate compared with the virulent isolates.

DISCUSSION

These results show that UCB can be used as a model to study infection, hopefully leading to new therapies for neonates and UCBT recipients.

Mycobacterium tuberculosis in Taiwan

OBJECTIVE

The resurgence of tuberculosis (TB) and the emergence of drug resistance of Mycobacterium tuberculosis (MTB) isolates are of great impact on public health.

METHODS

Taiwanese data on disease burden of TB and anti-microbial resistance of MTB identified from Annual Reports of Centre for Disease Control, Department of Health, Taiwan and from peer-reviewed publications from MEDLINE (1995-2004).

RESULTS

In Taiwan in 2002, the incidence (per 100,000 population) of tuberculosis was 74.6 and it was higher in aborigines (289.8) and in people living in mountainous regions (256.0). The mortality rate of tuberculosis in Taiwan in 2002 was 5.68 per 100,000 population. Susceptibility data summarized from 1990 to 2002 reports showed primary resistance ranged from 4.7 to 12% for isoniazid, 0.7 to 5.9% for rifampin, 1 to 6% for ethambutol, and 4 to 11% for streptomycin. The overall rates of multidrug-resistant tuberculosis (MDRTB) among new cases and previously treated cases were 1 to 3% and 15 to 46%, respectively. The increasing burden of patients with MDRTB infection, the persistent high rate of mortality, the lack of nationwide surveillance system using the standard methodology to determine the trends and current status of resistance, and the inadequate current TB control infrastructure and training to accomplish the tasks required to implement the directly observed treatment short-course (DOTS) strategy are having a great impact on public health in Taiwan.

CONCLUSIONS

High disease burden of TB and high resistance rates in MTB as well as inappropriateness of the current control infrastructure for TB services illustrate increasingly serious health problems from TB in Taiwan.

Tuberculosis in stem cell transplant patients

Tuberculosis (TB) is an increasing health problem, and patients undergoing stem cell transplantation (SCT) are at high risk of acquiring TB. Following a review of the medical literature, this article reports the current situation of TB in SCT patients. A PubMed search was undertaken using the keywords 'tuberculosis', 'stem cell transplantation' and 'bone marrow transplantation', and cases with meaningful data for analysis were included. The medical literature contains relatively few data on TB and SCT. Although there is a risk of TB in allogeneic SCT patients, this is less than in solid organ transplant patients, and the risk in autologous SCT patients is similar to the risk in the general population. The incidence of TB in SCT patients is proportional to the incidence of TB in the general population. Evidence favouring TB prophylaxis is not well established. While allogeneic transplantation carries a risk of TB, this is not true for autologous transplantation. Prophylaxis can only be an option for selected patients or countries with high rates of TB.

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.

Infectious complications after heart transplantation in Chinese recipients

Several factors appear to influence the incidence and type of infectious complications among different populations of transplant recipients. This study sought to assess the incidence and type of infection after transplantation in Chinese heart allograft recipients. A total of 130 infectious episodes occurred in 192 consecutive heart transplantation patients between June 1993 and May 2004. The median length of follow-up was 46.7+/-38.4 months. The 1-, 5- and 10-year survival rates were 81.8+/-2.8%, 63.0+/-3.8% and 45.7+/-7.7%. Infection was the leading cause of early and late deaths. Of the infectious episodes, 66 (51%) were caused by bacteria, 35 (27%) by viruses, 10 (8%) by fungi, 7 (5%) by Mycobacterium tuberculosis and 12 (9%) by other pathogens. The most common bacterial infectious episodes were caused by methicillin-resistant Staphylococcus aureus (20 of 66). The most common viral infections were varicella zoster virus infection in 12 (34%), cytomegalovirus infection in 9 (26%) and hepatitis B virus infection in 8 (23%). There was only one episode of clinical syndrome compatible to Pneumocystis jiroveci pneumonia. In conclusion, there was low incidence of Pneumocystis jiroveci pneumonia and cytomegalovirus infection, and high incidence of Mycobacterium tuberculosis infection in Chinese heart allograft recipients.

Tuberculosis in allogeneic stem cell transplant recipients: still a problem in the 21st century

Allogeneic stem cell transplant (ASCT) recipients have severely impaired cell-mediated immunity as a result of their conditioning regimen, immunosuppressive therapy, and graft-versus-host disease (GVHD). Accordingly, they are susceptible to bacterial, viral, and fungal infections. Mycobacterial infections can also occur in these patients, although the incidence is not high, even in countries where tuberculosis (TB) is common. We describe four patients from our hospital who developed pulmonary T tuberculous infection in the post-transplant period over a 3-year period. During that time a total of 127 patients have undergone an ASCT, representing an incidence of TB of 2.3%. The pretransplant diagnosis was acute myeloid leukemia in three patients and chronic myeloid leukemia in one case. All four patients were treated with a combination of cyclosporine and corticosteroids for acute and/or chronic GVHD. Three of the four patients were born outside Australia, each from an area where TB is endemic. Two patients died within 2 weeks of the commencement of antituberculous therapy, the third is alive and well, and the fourth died of multi-organ failure and sepsis after 4 months in hospital. A higher index of suspicion of previous TB exposure and infection is required in the assessment of ASCT recipients, particularly in those born in areas where TB is common or endemic.

Disseminated tuberculosis following reduced-intensity cord blood transplantation for adult patients with hematological diseases

Allogeneic hematopoietic stem cell transplantation (allo-SCT) recipients are prone to infections. The incidences of mycobacterial infections after allo-SCT in several case series vary from less than 0.1-5.5%. However, no study has been published on tuberculosis following unrelated cord blood transplantation (UCBT). We retrospectively reviewed medical records of 113 adult patients with a median age of 54 years who underwent reduced-intensity UCBT (RI-UCBT) at Toranomon Hospital from March 2002 to May 2004. Mycobacterium tuberculosis infections were diagnosed in three patients (2.7%), of these two patients developed primary infection and one patient developed reactivation of latent tuberculosis. The interval between RI-UCBT and the diagnosis of tuberculosis was 34, 41 and 61 days. All the patients had disseminated disease at diagnosis. Histological examination showed the lack of granuloma in caseous necrosis. Combination antituberculous treatments showed limited efficacy, and two patients died immediately after diagnosis. M. tuberculosis caused life-threatening illness, rapidly progressing in RI-UCBT recipients. The lack of granuloma in caseous necrosis suggests the impaired T-cell function in early post transplant phase of RI-UCBT. We should consider M. tuberculosis in the differential diagnoses of fever of unknown source after RI-UCBT.

Infectious complications and outcomes after allogeneic hematopoietic stem cell transplantation in Korea

We reviewed 242 allogeneic hematopoietic stem cell transplantation (HSCT) recipients retrospectively over a 2-year period (January 1998-December 1999) in order to analyze the characteristics and assess the outcomes of infectious complications in patients after HSCT in Korea. Bacteria were the major pathogens before engraftment, and viral and fungal infections predominated during the post-engraftment period. Varicella zoster virus was the most common viral pathogen after engraftment. Cytomegalovirus disease occurred mainly in the late-recovery phase. The frequency of mold infection was higher than that of yeast. There was a relatively high incidence of tuberculosis (3.0%) and Pneumocystis carinii pneumonia (6.5%). One case of death by measles confirmed by autopsy was also noted. Overall, cumulative mortality was 43% (104/242), and 59.6% of these deaths (62/104) were infection-related. Allogeneic HSCT recipients from unrelated donors were prone to infectious complication and higher mortality than those from matched sibling (17/39 (43.6%) vs 45/203 (22.2%), respectively; P<0.01; odd ratio 2.5; 95% confidence interval 1.2-5.1). As infection was the main post-HSCT complication in our data, more attention should be given to the management of infections in HSCT recipients.

Mycobacterial Infection: A Difficult and Late Diagnosis in Stem Cell Transplant Recipients

The Infectious Diseases Working Party of the European Blood and Marrow Transplant Group conducted a survey to obtain information about the frequency, presentation, and treatment of mycobacterial infection (MBI) in stem cell transplant (SCT) recipients. Among 29 centers, MBI was diagnosed in 0.79% of 1513 allogeneic and 0.23% of 3012 autologous SCT recipients during 1994-1998 a median of 160 days after transplantation. The mean interval between first symptoms and diagnosis was 29 days and was still longer for patients with atypical MBI or recipients of corticosteroid therapy. The prevalence of MBI was highest among those who received matched unrelated or mismatched STCs from related donors. Of 31 patients, 20 had tuberculosis, 8 had atypical MBI, and 3 had diagnoses based on histological findings only. Five patients (16%) died, all of whom had received an allogeneic SCT. Because of the increased numbers of unmatched donors and transplantation programs in countries with a high prevalence of tuberculosis, constant vigilance is required to early detect MBI in SCT recipients.