INFECTION IN THE BONE MARROW TRANSPLANT RECIPIENT

Clinical impact and early prediction of carbapenem-resistant Pseudomonas aeruginosa bacteraemia in allogeneic hematopoietic stem cell transplantation recipients

OBJECTIVE

Although antipseudomonal agents are administered in high-risk patients, no reports have focused on the risk of carbapenem-resistant (CR) Pseudomonas aeruginosa bacteraemia in allogeneic hematopoietic stem cell transplantation (allo-HSCT) recipients.

METHODS

We retrospectively studied a cohort of adult allo-HSCT recipients with P. aeruginosa bacteraemia, focusing on a comparison between carbapenem-sensitive (CS) and CR P. aeruginosa after initiating conditioning chemotherapy at our institute between January 2005 and December 2020. The incidence, all-cause 30-d mortality of P. aeruginosa bacteraemia, and risk factors for carbapenem resistance among patients with P. aeruginosa bacteraemia in allo-HSCT recipients were evaluated.

RESULTS

Forty-eight patients with P. aeruginosa bacteraemia were included, with an incidence of 3.84/100 recipients (CS = 1.92 vs. CR = 1.92). The all-cause 30-d mortality was significantly higher in CR P. aeruginosa bacteraemia (CS = 4.2% vs. CR = 39.1%; P = 0.003). The factor significantly associated with CR P. aeruginosa bacteraemia was carbapenem use for at least 3 d within 30 d before the onset of bacteraemia (odds ratio = 8.92; 95% confidence interval: 1.35-58.90). Inappropriate antimicrobial selection was significantly more frequent in CR P. aeruginosa bacteraemia (CS = 0% vs. CR = 29.2%; P ˂ 0.009).

CONCLUSION

Empirical combination therapy with reference to antimicrobial susceptibility profiles in each institution should be considered when CR P. aeruginosa bacteraemia is suspected in allo-HSCT recipients based on the risk of carbapenem exposure.

Multiple Reactivations of Viral Infections Followed by Cerebral Toxoplasmosis After Allogeneic Hematopoietic Stem Cell Transplantation in an Adolescent With Ph(+) Acute Lymphoblastic Leukemia: A Case Report

After allogeneic hematopoietic stem cell transplantation (allo-HSCT), especially from an unrelated donor, infectious complications are frequent and severe, sometimes with fatal outcomes. Despite using highly sensitive molecular techniques for close monitoring in the early post-transplant period for early diagnosis, not every viral infection or reactivation can be detected adequately early, even with highly sensitive methods. Particularly after toxic and deeply immunosuppressive treatment, multiple infections or reactivations, uncommon infections, or infections in unusual locations can occur. Here, we present a case of multiple viral infections or reactivations and cerebral toxoplasmosis in a 17-year-old youth with Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ ALL) treated with allo-HSCT who suffered multiple viral infections followed by cerebral toxoplasmosis.

Delay of alternative antiviral therapy and poor outcomes of acyclovir-resistant herpes simplex virus infections in recipients of allogeneic stem cell transplant - a retrospective study

Acyclovir is commonly used to prevent and treat herpes simplex virus (HSV) reactivation after hematopoietic cell transplant (HCT), and only few reports have been published on acyclovir-resistant HSV in HCT recipients. We reviewed the medical records of patients with a microbiologic diagnosis of acyclovir-resistant HSV by plaque reduction test who received an HCT from 2002 through 2014. A total of 4 028 HCTs were performed during the study period, and 18 of the recipients met the diagnostic criteria for acyclovir-resistant HSV. All cases had undergone allogeneic HCTs. Most patients were in the pre-engraftment period or on systemic corticosteroid therapy for graft-versus-host disease (GVHD). The median time between diagnosis and susceptibility testing was 15 days, and antiviral therapy was changed at a median of 27 days. Patients required prolonged therapy (~80 days), and many had serious complications including renal failure and hospitalization. In conclusion, acyclovir-resistant HSV infection is more likely during the period of profound deficit in T-cell-mediated immunity and is associated with significant morbidities. Higher doses of acyclovir prophylaxis might be needed for patients with history of HSV during pre-engraftment or GVHD treatment. In patients who do not respond or progress after 1 week of acyclovir therapy, testing for drug-resistant HSV, and early switch to an alternative antiviral should be considered.

Utility of routine surveillance blood cultures in asymptomatic allogeneic hematopoietic stem cell transplant recipients with indwelling central venous catheters at a comprehensive cancer center

BACKGROUND

Many transplant centers obtain surveillance blood cultures (SBCs) from asymptomatic allogeneic hematopoietic stem cell transplant (allo-HCT) recipients with central venous catheters for early detection of potential blood stream infections. The aim of this study was to determine the utility of this practice.

METHODS

We conducted a retrospective study of all patients who underwent allo-HCT to determine the frequency, clinical significance, and costs associated with SBCs.

RESULTS

From 776 patients, 6,801 SBCs were obtained (median, 9 per patient). Most (96.89%) were negative. Of the 211 positive SBCs, 171 (81%) had minimal clinical significance. The remaining 40 positive cultures (19%) were considered potentially significant. The frequency of potentially significant SBCs was 5.1% for the entire cohort and 0.59% of all SBCs drawn.

CONCLUSION

All potentially significant cultures and some that were deemed to have minimal significance led to medical intervention, some of which were probably unnecessary. No adverse outcomes occurred in patients with positive SBCs for the first 30 days following the positive result, regardless of the pathogen isolated or the quantitative colony count. The frequency of clinically significant positive SBCs in asymptomatic adult allo-HCT recipients is very low. Routine use of this practice leads to some unnecessary medical interventions and added costs.

Respiratory viral infections after hematopoietic stem cell transplantation in children

This study was performed to characterize respiratory viral infections in pediatric patients undergoing hematopoietic stem cell transplantation (HSCT). Study samples included 402 respiratory specimens obtained from 358 clinical episodes that occurred in the 116 children of the 175 consecutive HSCT cohort at Seoul National University Children's Hospital, Korea from 2007 to 2010. Multiplex reverse-transcription polymerase chain reactions were performed for rhinovirus, respiratory syncytial virus (RSV), parainfluenza viruses (PIVs), adenovirus, human coronavirus (hCoV), influenza viruses and human metapneumovirus. Viruses were identified in 89 clinical episodes that occurred in 58 patients. Among the 89 clinical episodes, frequently detected viruses were rhinovirus in 25 (28.1%), RSV in 23 (25.8%), PIV-3 in 16 (18.0%), adenovirus in 12 (13.5%), and hCoV in 10 (11.2%). Lower respiratory tract infections were diagnosed in 34 (38.2%). Neutropenia was present in 24 (27.0%) episodes and lymphopenia was in 31 (34.8%) episodes. Sixty-three percent of the clinical episodes were hospital-acquired. Three patients died of respiratory failure caused by respiratory viral infections. Respiratory viral infections in pediatric patients who have undergone HSCT are common and are frequently acquired during hospitalization. Continuous monitoring is required to determine the role of respiratory viruses in immunocompromised children and the importance of preventive strategies.

The utility of routine surveillance blood cultures in asymptomatic hematopoietic stem cell transplant patients

INTRODUCTION

Surveillance blood cultures (BCs) are often obtained in hematopoietic stem cell transplant (HSCT) patients for earlier detection of blood stream infections (BSI). The major aim of this study was to determine the utility of the current practice of obtaining surveillance blood cultures from asymptomatic transplant patients upon admission for the preparative regimen.

METHODS

We conducted an 8-year retrospective study of all patients consecutively admitted to the hospital for a HSCT from 2000 to 2008.

RESULTS

In this retrospective analysis, surveillance BCs from 191 eligible patients were analyzed. The incidence of definitive BSIs was 0.52% (1/191) with 6 BCs from other HSCT patients growing probable contaminants. The overall incidence of positive surveillance BCs was 2.9% (7/238) for the BCs taken and 3.7% (7/191) for patients cultured with coagulase negative staphylococcus being isolated from 6 of the 7 patients. The probability of increased BSI after transplantation in patients with initial positive surveillance BCs compared with those having negative BCs, was not significant (P=0.675). No infection-related mortality was observed during the first 60 days posttransplantation in these patients.

CONCLUSIONS

The frequency of positive surveillance BCs in asymptomatic HSCT patients at the time of hospital admission for transplant seems to be extremely low. These results, if confirmed by larger studies, show the reduced utility of obtaining surveillance BC in asymptomatic patients before administration of the conditioning regimen and the need for re-evaluation of this practice.

Performing allogeneic and autologous hematopoietic SCT in the outpatient setting: effects on infectious complications and early transplant outcomes

This retrospective single-center study compared the incidence, spectrum and effect of infections in 1045 consecutive allogeneic (allo) and autologous (auto) hematopoietic SCT (HSCT) performed between 1995 and 2006 in the inpatient (IP) or outpatient (OP) setting. We analyzed 374 allo-HSCT (196 IP and 178 OP) and 671 auto-HSCT (163 IP and 508 OP). The incidence of infection was lower both in auto-OP (25% OP vs 33% IP, P=0.042) and allo-OP cohorts (42.7% OP vs 55.6% IP, P=0.012). The mean number of infections per transplant was lower in both auto-OP (0.39 OP vs 0.57 IP, P=0.05) and in allo-OP cohorts (0.78 OP vs 1.09 IP, P=0.018). The 100-day non-relapse mortality (NRM) for OP auto-HSCT was 4.72% and for IP 3.95% (P=0.68). The 100-day NRM for OP allo-HSCT was lower at 14.1% than it was for IP at 22.6% (P=0.041). Time to onset of first infection and spectrum of infections was similar in all groups. We conclude that performing allo- and auto-HSCT in the OP setting results in short-term outcomes, including infections complications that are comparable to the standard IP setting.

Decreasing mortality rate in early pneumonia following hematopoietic stem cell transplantation

Pulmonary complications after allogeneic hematopoietic stem-cell transplantation (HSCT) remain 1 of the most important causes of morbidity and mortality. This study evaluates the change over time of incidence, aetiology and risk factors for death related to pneumonia within 3 months after HSCT. 997 patients who underwent HSCT were studied retrospectively. Most patients (83%) had a haematological malignancy. The majority (89%) had an HLA-A, -B, and -DR matched related or unrelated donor. Conditioning consisted of cyclophosphamide and total-body irradiation or busulfan and graft-versus-host disease prophylaxis of cyclosporin and methotrexate in most cases. Death related to pneumonia occurred in 56 (5.6%) patients. Cytomegalovirus (37%) was the main pathogen involved, especially during the first 2 decades studied. In the multivariate risk factor analysis, we found that death from pneumonia was significantly associated with receiving a T-cell depleted graft (p<0.001), bacteraemia (p=0.001), and y of transplantation (p<0.001). In patients receiving a transplant during the last decade, the incidence of death related to pneumonia was 2.8% compared to 8.9% during the first decade. We conclude that the rate of mortality related to pneumonia has decreased over time, possibly as a result of improved diagnostic, prophylactic and therapeutic methods and treatment.

Biocidal textiles can help fight nosocomial infections

The rates of nosocomial infections, especially by those caused by antibiotic resistant bacteria, are increasing alarmingly over the globe. Although more rigorous infection control measures are being implemented, it is clear that the current modalities to reduce nosocomial infections are not sufficient. Textiles are an excellent substrate for bacterial growth under appropriate moisture and temperature conditions. Patients shed bacteria and contaminate their pyjamas and sheets. The temperature and humidity between the patients and the bed are appropriate conditions allowing for effective bacterial proliferation. Several studies have found that personnel in contact with contaminated textiles were the source of transmission of the micro-organisms to susceptible patients. Furthermore, it has been reported that bed making in hospitals releases large quantities of micro-organisms into the air, which contaminate the immediate and non-immediate surroundings. Contaminated textiles in hospitals can thus be an important source of microbes contributing to endogenous, indirect-contact, and aerosol transmission of nosocomial related pathogens. We hypothesize that the use of antimicrobial textiles, especially in those textiles that are in close contact with the patients, may significantly reduce bioburden in clinical settings and consequently reduce the risk of nosocomial infections. These textiles should possess broad spectrum biocidal properties. They should be safe for use and highly effective against antibiotic resistant micro-organisms, including those that are commonly involved in hospital-acquired infections, and they should not permit the development of resistant micro-organisms to the active compound.

Invasive Pseudomonas aeruginosa infections: high rate of recurrence and mortality after hematopoietic cell transplantation

Limited data exist regarding the incidence and factors associated with outcome of invasive Pseudomonal infections in hematopoietic cell transplant (HCT). A retrospective analysis of cases of invasive Pseudomonas aeruginosa infection and factors associated with outcome was performed. P. aeruginosa invasive infection occurred in 95 of 5772 patients (1.65%) a median of 63 days after HCT (range 5-1435). Only 28% of infections occurred during periods of neutropenia (absolute neutrophil count<500 cells/mm(3)). Infection-attributable mortality during the initial episode of infection was 35.8%. Factors associated with initial mortality included the presence of a copathogen and high-dose steroid use. Ten (16.4%) of those who survived the initial infection experienced a recurrence of P. aeruginosa infection at a median of 9 days (range 3-17) after stopping antibiotics and 60% of those died as a result of recurrent infection a median of 1 day (range 1-7) after onset of recurrence. Grade 3-4 graft-versus-host disease was associated with a higher risk of recurrent infection. The risk of recurrence was not influenced by the presence of copathogens. Thus, invasive P. aeruginosa infections are associated with high recurrence rates and mortality in this immunocompromised population. Aggressive attempts to reduce immunosuppression and to treat copathogens may help during the initial infection.

Non-bacterial infections in allogeneic non-myeloablative stem cell transplant recipients

Data on non-bacterial infections during allogeneic non-myeloablative hematopoietic stem cell transplantation (HSCT) are widely different. We evaluated data on 48 consecutive patients who received a conditioning regimen with fludarabine and cyclophosphamide (73%) or fludarabine and total body irradiation (27%) and then underwent allogeneic non-myeloablative HSCT. Cytomegalovirus (CMV) infection was common and occurred in 48% of patients; 3 patients developed CMV disease, and all survived. CMV reactivation was found to be common with both conditioning regimens in our patient population. Invasive aspergillosis occurred in 4 patients (8%) and 3 died. Other serious non-bacterial infections were uncommon. Review of the available literature on non-myeloablative HSCT suggests that the frequency and type of opportunistic infections vary considerably.

Autopsy-proven causes of death in lungs of patients immunocompromised by secondary interstitial pneumonia

PURPOSE

To present the more frequent associations found in autopsies of immunocompromised patients who developed secondary interstitial pneumonia as well as the risk of death (odds ratio) in having specific secondary interstitial pneumonia according to the cause of immunocompromise.

METHOD

From January 1994 to March 2004, 17,000 autopsies were performed at Hospital das Clínicas, São Paulo University Medical School. After examining the pathology report review, we selected 558 of these autopsies (3.28%) from patients aged 15 years or more with primary underlying diseases who developed radiologically diffuse infiltrates of the lung during their hospital course and died after secondary interstitial pneumonia (bronchopneumonia, lobar pneumonia, interstitial pneumonia, diffuse alveolar damage, pulmonary recurrence of underlying disease, drug-induced lung disease, cardiogenic pulmonary edema, or pulmonary embolism). Histology slides were reviewed by experienced pathologists to confirm or not the presence of secondary interstitial pneumonia. Statistical analysis included the Fisher exact test to verify any association between histopathology and the cause of immunocompromise; a logistic regression was used to predict the risk of death for specific histological findings for each of the independent variables in the model.

RESULTS

Secondary interstitial pneumonia was histologically represented by diffuse interstitial pneumonitis ranging from mild nonspecific findings (n = 213) to a pattern of diffuse alveolar damage (n = 273). The principal causes of immunocompromise in patients with diffuse alveolar damage were sepsis (136 cases), neoplasia (113 cases), diabetes mellitus (37 cases), and transplantation (48 cases). A high risk of death by pulmonary edema was found for patients with carcinoma of colon. Similarly, in patients with lung cancer or cachexia, A high risk of death by bronchopneumonia (OR = 3.6; OR = 2.6, respectively) was found. Pulmonary thromboembolism was associated with an appreciable risk of death (OR = 2.4) in patients with arterial hypertension. The risk of death was also high in patients presenting hepatic cancer (OR = 2.5) or steroid therapy (OR = 2.4) who developed pulmonary hemorrhage as the histological pattern of secondary interstitial pneumonia . The risk of death by lung metastasis was also elevated (OR = 1.6) for patients that were immunosuppressed after radiotherapy.

CONCLUSION

Patients with secondary immunosuppression who developed secondary interstitial pneumonia during treatment in hospital should be evaluated to avoid death by diffuse alveolar damage, pulmonary edema, bronchopneumonia, lung hemorrhage, pulmonary thromboembolism, or lung metastasis. The high-risk patients are those immunosuppressed by hematologic disease; those under steroid treatment; or those with colon or hepatic carcinoma, cachexia, or arterial hypertension.

Treatment of multidrug-resistant cytomegalovirus retinitis with systemically administered leflunomide

Multiresistant cytomegalovirus (CMV) infection is increasingly recognized in solid organ transplant recipients. Leflunomide is a novel drug with both immunosuppressive and anti-CMV properties. Herein we report a case of a renal transplant recipient treated with leflunomide for multiresistant CMV retinitis, and provide correlation between serum and vitreous levels of leflunomide. She had stabilization of her retinitis and measurable levels of drug in her vitreous fluid and serum. These initial findings suggest that leflunomide may be useful in the treatment of CMV disease, including retinitis in patients after solid organ transplantation.

Actividad in vitro de las equinocandinas ¿Cómo debe evaluarse?

Echinocandins are a novel class of antifungal drugs. They have good activity against Candida spp and Aspergillus spp. Their low selective toxicity allows their administration at high doses with few secondary side effects. We have reviewed the available data on the endpoints for these drugs in their in vitro susceptibility testing on yeasts and moulds. The microdilution broth method is the most commonly used technique and MIC-1 (80% of growth inhibition) seems to be the most reliable endpoint when yeasts are tested. This endpoint also seems to be the most appropriate for the different drugs when they are combined with echinocandins using the checkerboard method for testing yeasts. By contrast, in the case of moulds, the minimum effective concentration (MEC) correlates better with the in vivo activity than the MIC when echinocandins are tested, and when these drugs are combined with other antifungals, MIC-2 (50% of growth inhibition) seems the most appropriate endpoint. Criteria based on drug pharmacodynamics is the most useful to define the echinocandin endpoints that best correlate with their in vivo efficacy.

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.

Prospective study of respiratory viral infections in pediatric hemopoietic stem cell transplantation patients

BACKGROUND

Community-acquired respiratory viruses are an important cause of respiratory disease in pediatric patients undergoing hemopoietic stem cell transplantation. However, there are no studies examining the impact of more rapid and sensitive diagnosis by real time polymerase chain reaction (PCR) in this population. We performed a prospective study to assess the impact of real time PCR diagnosis as well as protective isolation for community-acquired respiratory virus infections in pediatric patients undergoing hemopoietic stem cell transplantation.

METHODS

During a 2-year period, 39 pediatric patients undergoing hemopoietic stem cell transplantation were analyzed for presence of respiratory viruses. Samples were taken at regular intervals and analyzed by culture and newly developed real time PCR methods. All patients were cared for in protective isolation.

RESULTS

Respiratory symptoms were observed in 10 of the 39 cases (26%) and a virus was identified in 8 and 6 of these cases by PCR and culture, respectively. The PCR detected the respiratory infection a median of 8 days before culture. However, the morbidity of the respiratory infections was generally mild, and no mortality was observed. Additionally all infections were observed pretransplant or after discharge; no nosocomial infections were observed.

CONCLUSIONS

The real time PCR assay is more rapid and sensitive than culture and could be used to screen patients before transplant or as respiratory symptoms present for timely diagnosis.

Kinetics of myeloid and lymphocyte recovery and infectious complications after unrelated umbilical cord blood versus HLA-matched unrelated donor allogeneic transplantation in adults

Sources for allogeneic stem cells for patients with haematological disorders lacking a histocompatible sibling donor include matched unrelated donor (MUD) and umbilical cord blood (UCB). A total of 51 patients with haematological disorders, treated with myeloablation and transplantation with either unrelated human leucocyte antigen (HLA) partially matched UCB (28 patients) or HLA-matched MUD grafts (23 patients) during 1997-2003, were evaluated for life-threatening infections, haematological reconstitution, graft versus host disease, relapse and event-free survival (EFS). The median duration of neutropenia after transplantation was longer (29 d vs. 14 d) in the UCB group. The probability of donor-derived neutrophil engraftment by day 42 was 0.86 [95% confidence interval (CI) 0.71-1.0] in UCB recipients versus 0.96 (95% CI 0.87-1.0) in MUD recipients surviving >28 d. Overall infection rates were higher in UCB recipients, particularly at the early time points (before day +50) after transplantation. Graft failure occurred in five UCB recipients and two MUD recipients and was associated with the occurrence of bacteraemia during neutropenia. The EFS at 3-year follow-up was 0.25 in UCB and 0.35 in MUD recipients. UCB transplantation in adults is associated with delayed neutrophil and lymphocyte recovery compared with MUD grafting, and higher rates of bacteraemia at early time points after transplantation.

Erratum to “Apotransferrin administration prevents growth ofStaphylococcus epidermidisin serum of stem cell transplant patients by binding of free iron”

We investigated the effect of free, non-transferrin-bound iron occurring in haematological stem cell transplant patients on growth of Staphylococcus epidermidis in serum in vitro, and prevention of bacterial growth by exogenous apotransferrin. S. epidermidis did not grow in normal serum at inoculated bacterial densities up to 10(3) cfu ml(-1) but slow growth could be detected at higher initial inocula. Addition of free iron abolished the growth-inhibitory effect of serum, whereas addition of apotransferrin again restored it. Appearance of free iron and loss of growth inhibition coincided in patient serum samples taken daily during myeloablative therapy. Intravenously administered apotransferrin effectively bound free iron and restored the growth inhibition in patient sera. The results suggest that exogenous apotransferrin might protect stem cell transplant patients against infections by S. epidermidis and possibly other opportunistic pathogens.

Infectious complications after allogeneic stem cell transplantation: epidemiology and interventional therapy strategies--guidelines of the Infectious Diseases Working Party (AGIHO) of the German Society of Hematology and Oncology (DGHO)

The risk of infection after allogeneic stem cell transplantation is determined by the underlying disease, the intensity of previous treatments and complications that may have occurred during that time, but above all, the risk of infection is determined by the selected transplantation modality (e.g. HLA-match between the stem cell donor and recipient, T cell depletion of the graft, and others). In comparison with patients treated with high-dose chemotherapy and autologous stem cell transplantation, patients undergoing allogeneic stem cell transplantation are at a much higher risk of infection even after hematopoietic reconstitution, due to the delayed recovery of T and B cell functions. The rate at which immune function recovers after hematopoietic reconstitution greatly influences the incidence and type of post-transplant infectious complications. Infection-associated mortality, for example, is significantly higher following engraftment than during the short neutropenic period that immediately follows transplantation.

Apotransferrin administration prevents growth of Staphylococcus epidermidis in serum of stem cell transplant patients by binding of free iron

We investigated the effect of free, non-transferrin-bound iron occurring in haematological stem cell transplant patients on growth of Staphylococcus epidermidis in serum in vitro, and prevention of bacterial growth by exogenous apotransferrin. S. epidermidis did not grow in normal serum at inoculated bacterial densities up to 10(3) cfu ml(-1) but slow growth could be detected at higher initial inocula. Addition of free iron abolished the growth-inhibitory effect of serum, whereas addition of apotransferrin again restored it. Appearance of free iron and loss of growth inhibition coincided in patient serum samples taken daily during myeloablative therapy. Intravenously administered apotransferrin effectively bound free iron and restored the growth inhibition in patient sera. The results suggest that exogenous apotransferrin might protect stem cell transplant patients against infections by S. epidermidis and possibly other opportunistic pathogens.

Neutrophil defense in patients undergoing bone marrow transplantation: bactericidal/permeability-increasing protein (BPI) and defensins in graft-derived neutrophils

BACKGROUND

Even after neutrophil counts return to near normal levels, patients undergoing myeloablative chemotherapy and bone marrow transplantation (BMT) are at risk for invasive bacterial infections, raising the possibility that their neutrophil function might be impaired. To assess potential qualitative defects in neutrophil function in patients undergoing BMT, we measured neutrophil content of the antimicrobial (poly)peptides BPI and defensins.

METHODS

Neutrophil extracts were analyzed for content of BPI by Western blotting and ELISA and for defensin peptides by acid-urea polyacrylamide gel electrophoresis (PAGE). Antibacterial activity of neutrophil extracts was measured against Escherichia coli K1/r, a clinical isolate sensitive to synergistic killing by BPI and defensins.

RESULTS

Neutrophil extract BPI content on post-BMT days +20, +30, and +100 (169+/-35, 232+/-57, and 160+/-55 ng per 106 neutrophils, respectively) was similar to the neutrophil BPI content of normal controls (163+/-35 ng per 106 neutrophils). Neutrophil defensin content also did not vary during this time-span. Activity of neutrophil extracts against E. coli K1/r did not differ between BMT patients and controls.

CONCLUSION

At post-BMT days +20 to +100, neutrophils derived from engrafted marrow contain normal quantities of BPI and defensins. Any deficiencies of neutrophil function during this phase are not due to inadequate expression of these antimicrobial (poly)peptides but could reflect abnormalities in other aspects of neutrophil function.

Catheter-related candidemia caused by Candida lipolytica in a patient receiving allogeneic bone marrow transplantation

Candida lipolytica was recovered from the blood and the central venous catheter in a patient receiving allogeneic bone marrow transplantation. Two C. lipolytica strains from different geographical areas and the ATCC 9773 strain of C. lipolytica were used as controls. C. lipolytica was identified by standard methods. MICs indicated antifungal susceptibilities to amphotericin B, fluconazole, and itraconazole for all strains. In vitro testing and scanning electron microscopy showed that C. lipolytica was capable of producing large amounts of viscid slime material in glucose-containing solution, likely responsible for the ability of the yeast to adhere to catheter surfaces. Restriction fragment length polymorphisms revealed an identical profile for all clinical isolates, unrelated to those observed for the control strains. This finding suggested the absence of microevolutionary changes in the population of the infecting strain, despite the length of the sepsis and the potential selective pressure of amphotericin B, which had been administered to the patient for about 20 days. The genomic differences that emerged between the isolates and the control strains were indicative of a certain degree of genetic diversity between C. lipolytica isolates from different geographical areas.

Immunotherapy to reconstitute immunity to DNA viruses

Defects in cytotoxic T-lymphocyte (CTL) function after hemopoietic stem cell transplantation (HSCT) are associated with an increased frequency and severity of viral diseases. Initial investigations of viral infections in immunosuppressed mice and subsequent clinical studies of cytomegalovirus (CMV) and Epstein-Barr virus (EBV) in human stem cell transplant patients have suggested that adoptive transfer of virus-specific T cells may restore protective immunity and control established infections. Current efforts focus on optimizing adoptive immunotherapy approaches and developing strategies for generating T cells specific for multiple viruses to provide broader protection.

Respiratory virus infections in pediatric hematopoietic stem cell transplantation

Respiratory virus infections (RVI) have become an increasingly appreciated problem in the hematopoietic stem cell transplant (HSCT) population. A retrospective analysis of 274 patients undergoing 281 HSCT at St. Jude Children's Research Hospital from January 1994 through December 1997 was performed. Medical and clinical laboratory records were reviewed beginning at the onset of conditioning through the year following each HSCT, and the analysis was done for the first RVI only. Thirty-two (11%) of 281 HSCT cases developed a RVI during the first year post-HSCT. The most frequent cause of RVI was human parainfluenza virus type 3. Univariate analysis was performed to determine the association between risk factors and the cumulative incidence of RVI. Respiratory viruses are frequent causes of infections in the first year post-HSCT in the pediatric population. Only allogeneic transplant and the degree of acute or chronic graft versus host disease were found to be statistically significant risk factors for RVI.

Critical care of the hematopoietic stem cell patient

Hematopoietic stem cell transplantation is evolving into a treatment modality with expanding indications and volume and with excellent outcomes, although it carries significant risk for morbidity and mortality affecting most major organ systems and often requires ICU care. With continuing improvements in supportive care and specific therapy of complications following HCT including the open-lung strategy of mechanical ventilation, use of nitric oxide, less toxic myeloablative regimens, newer classes of antibiotics, and improved immunosuppression strategies, it is hoped that mortality in this setting will continue to decline in coming years.

Preventing opportunistic infections after hematopoietic stem cell transplantation: the Centers for Disease Control and Prevention, Infectious Diseases Society of America, and American Society for Blood and Marrow Transplantation Practice Guidelines and beyond

This review presents evidence-based guidelines for the prevention of infection after blood and marrow transplantation. Recommendations apply to all myeloablative transplants regardless of recipient (adult or child), type (allogeneic or autologous) or source (peripheral blood, marrow or cord blood) of transplant. In Section I, Dr. Dykewicz describes the methods used to rate the strength and quality of published evidence supporting these recommendations and details the two dozen scholarly societies and federal agencies involved in the genesis and review of the guidelines. In Section II, Dr. Longworth presents recommendations for hospital infection control. Hand hygiene, room ventilation, health care worker and visitor policies are detailed along with guidelines for control of specific nosocomial and community-acquired pathogens. In Section III, Dr. Boeckh details effective practices to prevent viral diseases. Leukocyte-depleted blood is recommended for cytomegalovirus (CMV) seronegative allografts, while ganciclovir given as prophylaxis or preemptive therapy based on pp65 antigenemia or DNA assays is advised for individuals at risk for CMV. Guidelines for preventing varicella-zoster virus (VZV), herpes simplex virus (HSV) and community respiratory virus infections are also presented. In Section IV, Drs. Baden and Rubin review means to prevent invasive fungal infections. Hospital design and policy can reduce exposure to air contaminated with fungal spores and fluconazole prophylaxis at 400 mg/day reduces invasive yeast infection. In Section V, Dr. Sepkowitz details effective clinical practices to reduce or prevent bacterial or protozoal disease after transplantation. In Section VI, Dr. Sullivan reviews vaccine-preventable infections and guidelines for active and passive immunizations for stem cell transplant recipients, family members and health care workers.

Screening sinus CT scans in pediatric bone marrow transplant patients

OBJECTIVE

To determine how sinus disease noted on pre-bone marrow transplant (BMT) screening sinus computed tomography (CT) scans relates to subsequent development of clinical and/or radiographic sinusitis and correlates with overall prognosis.

METHODS

A retrospective review of medical records, CT scans, and BMT database statistics was performed on all pediatric BMT recipients from January 1992 through December 1997. Fifty-four pre-BMT CT scans were performed on 51 children, aged from 2 months to 17 years. Sinus disease was staged according to criteria established by Lund and Kennedy [V.J. Lund, D.W. Kennedy, Ann. Otol. Rhinol. Laryngol. S167 (1995) 17-21.].

RESULTS

The average age of BMT recipients was 6.8 years. Most common oncologic diagnoses included acute myelogenous leukemia (37%), acute lymphoblastic leukemia (17%), and stage IV neuroblastoma (13%). Screening sinus CT scans were routinely performed 1-3 months prior to BMT. On pre-BMT CT scans 48% of the patients had no evidence of sinus disease, 25.9% mild disease, 9.3% moderate disease, and 16.7% severe disease. Two-thirds (66.7%) of patients with severe sinus disease on pre-BMT CT scans experienced clinical sinusitis post-BMT. In contrast, sinus symptoms were much less common (21.4%) in those with mild disease on CT scan. Overall, 39.3% of patients with sinus abnormalities on pre-BMT CT scans had clinical sinusitis during their post-BMT course, compared to 23.1% of those with normal CT scans pre-BMT. In addition, those patients demonstrating sinus disease on their pre-BMT CT scan were more likely to have radiographic sinusitis post-BMT (25.0%) than those with no disease (7.7%). Seventy-eight percent of those with severe sinusitis had died by 2-year follow up, compared to 69.2% of patients with normal CT scans pre-BMT.

CONCLUSIONS

Severity of radiographic sinus disease on pre-BMT CT scans was noted to correlate with clinical and radiographic sinusitis later in the post-BMT course, and was associated with a trend toward decreased survival. Pre-BMT CT scans may be useful in determining which children need early and more aggressive intervention for clinical sinusitis post-BMT.

Incidence and outcome of vancomycin-resistant enterococcal bacteremia following autologous peripheral blood stem cell transplantation

A retrospective evaluation of 321 consecutive recipients of high-dose chemotherapy (HDC) and autologous peripheral blood stem cell transplantation (PBSCT) was conducted to ascertain the incidence and outcome of vancomycin-resistant enterococcal (VRE) bacteremia. Ten patients developed VRE bacteremia at a median of 6 days following PBSCT. Nine isolates were Enterococcus faecium and one was E. faecalis. The median duration of bacteremia was 5 days. The central venous catheter was removed in seven individuals. Nine patients were treated with a variety of antimicrobial agents including quinupristin-dalfopristin, chloramphenicol, doxycycline, oral bacitracin, co-trimoxazole, and nitrofurantoin. Bacteremia resolved without adverse sequelae in seven patients. Two individuals who died of other causes had persistent or relapsed bacteremia at the time of death. An additional patient suffered multiple relapses of VRE bacteremia and died as a result of VRE endocarditis 605 days following PBSCT. Mortality as a direct result of VRE bacteremia was 10% in this series. The optimal type and duration of treatment of VRE bacteremia has not been clearly defined. Therefore, we perform weekly stool surveillance cultures for VRE in our hospitalized transplant population and apply strict barrier precautions in those individuals in whom stool colonization has been identified. Furthermore, the empiric use of vancomycin has been restricted. Bone Marrow Transplantation (2000) 25, 147-152.

High rates of Pneumocystis carinii pneumonia in allogeneic blood and marrow transplant recipients receiving dapsone prophylaxis

Chemoprophylaxis for Pneumocystis carinii pneumonia (PCP) is routinely given after allogeneic blood or marrow transplantation. We evaluated the effectiveness of dapsone prophylaxis (50 mg orally twice daily, 3 times per week) compared with twice-weekly trimethoprim-sulfamethoxazole (TMP-SMZ) in preventing PCP after allogeneic blood or marrow transplantation. Patients included all (n=646) who received allogeneic blood or marrow transplants between 1 September 1993 and 31 December 1996 who survived at least 100 days after transplantation. A cohort of 111 dapsone recipients was compared with the remaining 535 who received TMP-SMZ. Ten patients developed PCP; 8 were taking dapsone. PCP incidence in the TMP-SMZ cohort was 0.37% versus 7.2% for dapsone. The relative risk for PCP associated with dapsone use was 18.8 (P<.001) and was not accounted for by age, clinical extensive chronic graft-versus-host disease, donor source, or malignant relapse. Dapsone prophylaxis at this dosage is associated with significantly higher rates of PCP than is TMP-SMZ after allogeneic marrow transplantation. We advise caution in prescribing alternatives to TMP-SMZ prophylaxis in this setting.

Emerging fungal pathogens: evolving challenges to immunocompromised patients for the twenty-first century

Opportunistic fungi have emerged during the past decade as important causes of morbidity and mortality in immunocompromised patients. Candida species constitute the third to fourth most common causes of nosocomial blood stream infections, and Aspergillus species have emerged as the most common infectious cause of pneumonic mortality in bone marrow/stem cell transplant recipients. Among HIV-infected patients, meningoencephalitis due to Cryptococcus neoformans ranks among the most common AIDS-defining infections. Hyaline septated filamentous fungi, such as Fusarium species, Acremonium species, Paecilomyces species, and Trichoderma species, are increasingly reported as causing invasive mycoses refractory to conventional therapy. Dematiaceous septated filamentous fungi, such as Pseudallescheria boydii, Bipolaris species, and Cladophialophora bantiana cause pneumonia, sinusitis, and CNS infection unresponsive to current therapy. An increasing number of different members of the class of Zygomycetes are reported as causing lethal infections, despite aggressive medical and surgical interventions. Yet the treatment for zygomycosis has not changed in approximately 40 years. The prevalence of the endemic mycoses, such as those due to Penicillium marneffei, Coccidioides immitis, and Histoplasma capsulatum, has been reported to expand rapidly in response to environmental exposures and increased numbers of vulnerable hosts in endemic regions of the world. Dermatophytoses are occurring with increasing prevalence and morbidity in elderly and immunocompromised patients. As we enter the next millennium, we may anticipate that emergent fungal infections will continue to develop in the settings of permissive environmental conditions, selective antifungal pressure, and an expanding population of immunocompromised hosts.

Fatal disseminated Trichoderma longibrachiatum infection in an adult bone marrow transplant patient: species identification and review of the literature

Trichoderma longibrachiatum was recovered from stool surveillance cultures and a perirectal ulcer biopsy specimen from a 29-year-old male who had received an allogeneic bone marrow transplant for acute lymphoblastic leukemia. The amphotericin B (2.0 microgram/ml) and itraconazole (1.0 microgram/ml) MICs for the organism were elevated. Therapy with these agents was unsuccessful, and the patient died on day 58 posttransplantation. At autopsy, histologic sections from the lungs, liver, brain, and intestinal wall showed infiltration by branching septate hyphae. Cultures were positive for Trichoderma longibrachiatum. While Trichoderma species have been recognized to be pathogenic in profoundly immunosuppressed hosts with increasing frequency, this is the first report of probable acquisition through the gastrointestinal tract. Salient features regarding the identification of molds in the Trichoderma longibrachiatum species aggregate are presented.

Diagnosis of posttransplant granulocytic sarcoma by fine-needle aspiration cytology and flow cytometry

We describe a patient who developed granulocytic sarcomas of the mesentery and breast approximately 4 yrs following an allogenic bone marrow transplantation for acute myeloblastic leukemia. The diagnosis was made by a combination of fine-needle aspiration cytology and flow cytometry. The differential diagnoses of localized masses in posttransplant patients and how the combination of fine-needle aspiration cytology and flow cytometry may be used are discussed.

Nosocomial colonization, septicemia, and Hickman/Broviac catheter-related infections in bone marrow transplant recipients. A 5-year prospective study

In this 5-year prospective study of 242 bone marrow transplantation (BMT) recipients from whom daily blood cultures via the indwelling Broviac/Hickman catheter were obtained, there was a median of 35 catheter-days during hospitalization, mean of 40 days, and total of 9,667 catheter-days which were divided almost equally between neutropenic (4,771) and non-neutropenic (4,896) days. One hundred twenty (50%) patients had a total of 161 episodes of nosocomial bacterial or candidal infections. Overall, 81 (33%) patients experienced 100 episodes of catheter-related infections and 90 (37%) patients experienced 112 episodes of septicemia, including 51 episodes of catheter-related septicemia. There was an incidence of 11.59 septicemia episodes, including 5.28 catheter-related septicemia episodes, 2.48 colonization only (without subsequent septicemia), and 2.59 exit site infections only, per 1,000 catheter-days. Over a period of a total of 6,593 afebrile days, 34 (14%) patients developed 40 episodes of colonization, a rate of 6.07 per 1,000 afebrile days, of which 16 developed into septicemia. Twenty-five patients had 1 episode each of exit site infection without bacteremia. There were 10 (4%) septicemia-related deaths, 4 of which were catheter-related; 50% of all deaths involved Pseudomonas aeruginosa. The mortality due to catheter-related septicemic episodes was not greater than that of the non-catheter-related episodes. Neutropenia was found to be a significant risk factor in our study: 76% of the septicemia episodes (85/112) and 65% of the catheter-related infectious episodes (65/100) occurred during neutropenia. There was a higher incidence of septicemic episodes during neutropenia than during non-neutropenic periods, 17.82 versus 5.51 per 1,000 days (p < 0.0001), and a higher rate of catheter-related infections during the neutropenic period, 13.62 versus 7.15 during non-neutropenic days per 1,000 days (0.001). Fourteen of 16 colonization episodes developed into septicemia during neutropenia versus 2/24 during non-neutropenic periods, a rate of 5.47 versus 0.47 per 1,000 afebrile days, respectively (p < 0.0001), and 9/10 deaths occurred during neutropenia.

Soluble Fas Levels in Sera of Bone Marrow Transplantation Recipients Are Increased During Acute Graft-Versus-Host Disease But Not During Infections

Graft-versus-host disease (GVHD) and infections are two major complications of allogeneic bone marrow transplantation (BMT). In the course of GVHD, one of the pathways that activated cytotoxic T cells use to execute their killing mechanisms is the Fas/Fas ligand pathway. This killing mechanism might be accompanied by the release of soluble Fas (sFas) in the circulation. To examine the association of serum sFas levels and post-BMT complications, we have analyzed sFas levels in sera of bone marrow recipients with and without GVHD. Postallogeneic BMT sFas levels were significantly increased during clinically relevant acute GVHD (aGVHD; P = .002). However, during infections sFas levels tended to decrease (P = .088). Yet, the simultaneous occurrence of GVHD and infections resulted in extreme high sFas levels. These results suggested that sFas release may be correlated with the amount of tissue damage, because aGVHD induces more damage than infections. The presence of significantly increased sFas levels during aGVHD provides new insights into the GVHD pathogenesis.