Infections in adults undergoing unrelated donor bone marrow transplantation

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.

Impact of Discontinuing Levofloxacin Prophylaxis on Bloodstream Infections in Neutropenic Hematopoietic Stem Cell Transplantation Patients

Multidrug-resistant pathogens have emerged worldwide. We have driven the hypothesis that the non-use of fluoroquinolone prophylaxis during neutropenia could reduce antibiotic resistance in Gram-negative bacteria that cause bloodstream infections (BSIs) in hematopoietic stem cell transplantation (HSCT) patients and that this change in resistance pattern could lead to an impact on BSI mortality. This is a quasi-experimental study comparing BSI incidence, resistance patterns of bacteria that cause BSI, and BSI mortality when levofloxacin prophylaxis was routine for neutropenic HSCT patients (2016–2018) to when fluoroquinolone prophylaxis was discontinued in our center (2019). Bivariate comparisons and multivariate logistic regression models were used for analyses. A total of 310 HSCTs (66 (21%) allogeneic and 244 (79%) autologous) were performed during the study period. Sixty (19%) patients had BSIs, 30 in each evaluated period. The discontinuation of levofloxacin prophylaxis was associated with an increase in BSI incidence and a decrease in the resistance rates of causative BSI bacteria and in BSI 30-day mortality. The increase in the rate of resistant bacteria causing BSI and in BSI mortality might outweigh the benefits of a decrease in BSI incidence caused by fluoroquinolone prophylaxis in neutropenic HSCT patients. We suggest that the routine use of fluoroquinolone in this context be revisited.

Association between body image dissatisfaction and poor quality of life and depression among patients with hematopoietic stem cell transplantation

PURPOSE

This study aims to evaluate the association between body image dissatisfaction and quality of life and depression among patients after hematopoietic stem cell transplantation (HSCT).

METHODS

We conducted a cross-sectional survey at three university-based HSCT outpatient clinics and the Korea Blood Cancer Association. We assessed the body image using the body image scale; quality of life and depression were measured using the World Health Organization Quality of Life-BREF and the Patient Health Questionnaire 9, respectively. Univariate and multivariate linear regression models were used to find an association between body image, quality of life, and depression.

RESULTS

Among 163 study participants, 71.8% were male, and the mean age of the participants was 48.3 (SD = 11.2). Over 70% of the participants reported that they felt less physically and sexually attractive due to HSCT, and 39.3% of the patients were dissatisfied with their body image. In fully adjusted models, patients with dissatisfied body image had significantly poorer quality of life (- 13.68, 95% confidence interval [CI] = - 18.16, - 9.21). Moreover, patients with body image dissatisfaction were 8.59 times (95% CI = 3.79, 19.48) more likely to have depressive symptoms than patients without it.

CONCLUSION

The majority of HSCT patients experienced body image dissatisfaction, which was significantly associated with poor quality of life and depression. It would be essential to evaluate body image after HSCT and provide appropriate interventions for preventing further psychological consequences.

Patterns of infection and infectious-related mortality in patients receiving post-transplant high dose cyclophosphamide as graft-versus-host-disease prophylaxis: impact of HLA donor matching

Post-transplant cyclophosphamide (PTCy) has become a promising option after allo-SCT, but infections may be more common than in traditional protocols. We herein report 117 consecutive adults who received PTCy-based alloSCT in our hospital: HaploSCT (34%), MRD (19%), and VUD (47%), respectively. The 18-month incidence of severe bacterial, viral, and IFI was 56%, 69%, and 8.7%, without differences between donor type, except for CMV infection and viral hemorrhagic cystitis, which had a higher incidence in the haploSCT cohort (58% vs. 43% and 30% vs. 8% on day +90, p < 0.05). Late infections by conventional respiratory viruses were common in all groups [33/87 (38%)]. The 2-year survival was 72% and did not differ by donor type. IRM at day 30, day 100, and 18 months was 1.7%, 4.4%, and 12%, without differences by donor type (p = 0.7). The primary cause of IRM was bacterial infection (42%). Grade 2–4 acute GvHD was the only independent predictor of IRM. Donor type had no impact on IRM or on survival. In our study, severe infections were common in all donor types using PTCy, with higher rates of early post-engraftment CMV-I and viral HC in haploSCT recipients, although lethal infections were uncommon and similar in all donor types.

Bacterial Blood Stream Infections Negatively Impact on Outcome of Patients Treated with Allogeneic Stem Cell Transplantation: 6 Years Single-Centre Experience

BACKGROUND

Blood stream infections (BSIs) represent a major complication of allo-SCT and are a major cause of morbidity and mortality during and after bone marrow aplasia.

OBJECTIVES

The objective of this study was to describe the incidence and outcome of BSIs in a cohort of patients submitted to allo-SCT, in order to track changes of the epidemiology and bacteria resistance.

METHODS

We retrospectively analyzed the microbiological data of 162 patients allotransplanted in Brescia University Hospital, over a period of 6 years.

RESULTS

Eighty patients experienced a BSIs for a total of 119 isolates. In 77 cases (65%) a Gram positive bacteria was isolated, being coagulase negative Staphilococci the most frequent species (77% of the cases). In 42 cases (35%) a Gram negative bacteria was isolated (E. coli 57% and P. aeruginosa 24%). Fluoroquinolones resistance was frequent (90% for S. epidermidis, 92% for E. coli, 90% for P. aeruginosa). Methycillin resistance of S. epidermidis was 100%, 76% of E. coli were ESBL positive and among P. aeruginosa resistance to carbapenems was 40%. The 2 years overall survival of patients with BSIs vs patients without BSIs was 46% vs 60% (HR1,48, p=0,07). P. aeruginosa and E. coli were the species with the highest mortality (50% and 33%, respectively).

CONCLUSIONS

These data confirm that BSIs, mainly sustained by Gram positive bacteria, are frequent in allotransplanted patients (50% of the cases) and may influence the outcome of allotransplanted patients, being antibiotics resistance highly frequent among these bacteria.

Clinical significance of pre-transplant circulating CD3+ CD4+ CD161+ cell frequency on the occurrence of neutropenic infections after allogeneic stem cell transplantation

BACKGROUND

Few studies have been performed to identify factors that are associated with an increased risk of infections during the neutropenic period in patients undergoing allogeneic stem cell transplantation (allo-SCT). The aim of this study was to identify the host immune cells responsible for infections before engraftment.

METHODS

A total of 282 patients who underwent allo-SCT were enrolled. Peripheral blood samples were collected before conditioning therapy. Expression of CD161-expressing T cells, natural killer cells, and immature myeloid cells was analyzed by flow cytometry. Microbially and clinically defined infections and fevers of unknown origin as proposed by the Immunocompromised Host Society were included in this study.

RESULTS

The median age was 45 years (range, 16-68 years). Patients had various hematologic disorders and were transplanted from human leukocyte antigen (HLA)-matched siblings, unrelated donors, and familial HLA-mismatched donors. In univariate analysis, younger age and a familial HLA-mismatched donor were risk factors for the occurrence of infections. After adjusting for potential variables in univariate analysis, multivariate analyses revealed that a lower frequency of CD3⁺ CD4⁺ CD161⁺ cells was significantly associated with the occurrence of neutropenic infections. An age of 35 years or younger and allografting from familial HLA-mismatched donors showed a trend toward higher infection rates.

CONCLUSION

Our data indicated that a lower frequency of CD3⁺ CD4⁺ CD161⁺ T cells in peripheral blood before conditioning therapy was associated with a higher incidence of infection during the neutropenic period. These results suggest that recipient innate T cells with expression of C-type lectin CD161 can guard against infections before engraftment.

Matched unrelated donor transplants-State of the art in the 21st century

Hematopoietic stem cell transplantation (HSCT) is the therapy of choice in many hematological malignant and non-malignant diseases by using human leukocyte antigen (HLA)-matched siblings as stem cell source but only one third of the patients will have HLA-matched siblings. Hence, physicians rely on the availability of matched unrelated donors (URD). The possibility of finding a matched URD is now more than 70% due to continuous expansion of URD registries around the world. The use of URD in adult patients is steadily increasing and in the last 8 years has superseded the numbers of matched sibling donor transplants and has become the most commonly used stem cell source. There is also an increasing trend to use peripheral blood (PB) stem cells rather than bone marrow (BM) stem cells. Outcomes following URD transplants depend mainly upon the indication and urgency of transplant, age and comorbidities of recipients, cytomegalovirus (CMV) matching/mismatching between donor and the recipient, and degree of HLA matching. In some studies outcome of unrelated stem cell transplants in terms of treatment-related mortality (TRM), disease-free survival (DFS), and overall survival (OS) is comparable to sibling donors.

Parainfluenza virus infections in hematopoietic cell transplant recipients and hematologic malignancy patients: A systematic review

Parainfluenza viral infections are increasingly recognized as common causes of morbidity and mortality in cancer patients, particularly in hematopoietic cell transplant (HCT) recipients and hematologic malignancy (HM) patients because of their immunocompromised status and susceptibility to lower respiratory tract infections. Advances in diagnostic methods, including polymerase chain reaction, have led to increased identification and awareness of these infections. Lack of consensus on clinically significant endpoints and the small number of patients affected in each cancer institution every year make it difficult to assess the efficacy of new or available antiviral drugs. In this systematic review, we summarized data from all published studies on parainfluenza virus infections in HM patients and HCT recipients, focusing on incidence, risk factors, long-term outcomes, mortality, prevention, and management with available or new investigational agents. Vaccines against these viruses are lacking; thus, infection control measures remain the mainstay for preventing nosocomial spread. A multi-institutional collaborative effort is recommended to standardize and validate clinical endpoints for PIV infections, which will be essential for determining efficacy of future vaccine and antiviral therapies.

Could Histoplasma capsulatum Be Related to Healthcare-Associated Infections?

Healthcare-associated infections (HAI) are described in diverse settings. The main etiologic agents of HAI are bacteria (85%) and fungi (13%). Some factors increase the risk for HAI, particularly the use of medical devices; patients with severe cuts, wounds, and burns; stays in the intensive care unit, surgery, and hospital reconstruction works. Several fungal HAI are caused by Candida spp., usually from an endogenous source; however, cross-transmission via the hands of healthcare workers or contaminated devices can occur. Although other medically important fungi, such as Blastomyces dermatitidis, Paracoccidioides brasiliensis, and Histoplasma capsulatum, have never been considered nosocomial pathogens, there are some factors that point out the pros and cons for this possibility. Among these fungi, H. capsulatum infection has been linked to different medical devices and surgery implants. The filamentous form of H. capsulatum may be present in hospital settings, as this fungus adapts to different types of climates and has great dispersion ability. Although conventional pathogen identification techniques have never identified H. capsulatum in the hospital environment, molecular biology procedures could be useful in this setting. More research on H. capsulatum as a HAI etiologic agent is needed, since it causes a severe and often fatal disease in immunocompromised patients.

The Changing Epidemiology of Bloodstream Infections and Resistance in Hematopoietic Stem Cell Transplantation Recipients

OBJECTIVE

Patients receiving hematopoietic stem cell transplantation (HSCT) are exposed to highly immunosuppressive conditions and bloodstream infections (BSIs) are one of the most common major complications within this period. Our aim, in this study, was to evaluate the epidemiology of BSIs in these patients retrospectively.

MATERIALS AND METHODS

The epidemiological properties of 312 patients with HSCT were retrospectively evaluated.

RESULTS

A total of 312 patients, followed between 2000 and 2011, who underwent autologous (62%) and allogeneic (38%) HSCT were included in the study. The most common underlying malignancies were multiple myeloma (28%) and Hodgkin lymphoma (21.5%). A total of 142 (45%) patients developed at least 1 episode of BSI and 193 separate pathogens were isolated from the blood cultures. There was a trend of increase in the numbers of BSIs in 2005-2008 and a relative increase in the proportion of gram-positive infections in recent years (2009-2011), and central venous catheter-related BSI was found to be most common source. Coagulase-negative staphylococci (49.2%) and Acinetobacter baumannii (8.8%) were the most common pathogens. Extended-spectrum beta-lactamase-producing strains were 23% and 22% among Escherichia coli and Klebsiella spp. isolates, respectively. Quinolone resistance was detected in 10% of Enterobacteriaceae. Resistance to carbapenems was not detected in Enterobacteriaceae, while it was seen at 11.1% and 23.5% in Pseudomonas and Acinetobacter strains, respectively.

CONCLUSION

A shift was detected from gram-negative bacteria to gram-positive in the etiology over the years and central lines were the most common sources of BSIs.

Fungal and viral infections after allogeneic hematopoietic transplantation from unrelated donors in adults: improving outcomes over time

Umbilical cord blood (CB) is increasingly used as an alternative source of stem cells in adult unrelated transplantation. Although registry studies report similar overall outcomes in comparison with BM/PB, comparative studies focusing on severe infections and infection-RM (IRM) with a long follow-up are scarce. A total of 434 consecutive unrelated transplants (1997-2009) were retrospectively analyzed to compare overall outcomes, incidence and risk factors of severe viral and invasive fungal infections in CB (n=65) vs BM/PB recipients (n=369). The 5-year OS was 38 vs 43%, respectively (P=0.2). CB transplantation (CBT) was associated with a higher risk of invasive aspergillosis (100-days-cumulative incidence 16 vs 6%, P=0.04) and CMV infection without differences in RM. No statistically significant differences were found regarding NRM (NRM of 38% in CB vs 37% in BM/PB at 1 year) nor IRM (30% in CB vs 27% in BM/PB at 1 year). In the overall population, NRM and IRM improved in more recent years. In adults who receive a single CBT, the risk of severe infections is increased when compared with unrelated BM/PB recipients, but mortality from infections is similar, leading to similar NRM and survival.

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

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

Nosocomial fungal infections: epidemiology, infection control, and prevention

Fungal infections are an increasing cause of morbidity and mortality in hospitalized patients. This article reviews the current epidemiology of nosocomial fungal infections in adult patients, with an emphasis on invasive candidiasis and aspergillosis. Recently published recommendations and guidelines for the control and prevention of these nosocomial fungal infections are summarized.

Resistance of herpes simplex viruses to nucleoside analogues: mechanisms, prevalence, and management

Herpes simplex viruses (HSV) type 1 and type 2 are responsible for recurrent orolabial and genital infections. The standard therapy for the management of HSV infections includes acyclovir (ACV) and penciclovir (PCV) with their respective prodrugs valacyclovir and famciclovir. These compounds are phosphorylated by the viral thymidine kinase (TK) and then by cellular kinases. The triphosphate forms selectively inhibit the viral DNA polymerase (DNA pol) activity. Drug-resistant HSV isolates are frequently recovered from immunocompromised patients but rarely found in immunocompetent subjects. The gold standard phenotypic method for evaluating the susceptibility of HSV isolates to antiviral drugs is the plaque reduction assay. Plaque autoradiography allows the associated phenotype to be distinguished (TK-wild-type, TK-negative, TK-low-producer, or TK-altered viruses or mixtures of wild-type and mutant viruses). Genotypic characterization of drug-resistant isolates can reveal mutations located in the viral TK and/or in the DNA pol genes. Recombinant HSV mutants can be generated to analyze the contribution of each specific mutation with regard to the drug resistance phenotype. Most ACV-resistant mutants exhibit some reduction in their capacity to establish latency and to reactivate, as well as in their degree of neurovirulence in animal models of HSV infection. For instance, TK-negative HSV mutants establish latency with a lower efficiency than wild-type strains and reactivate poorly. DNA pol HSV mutants exhibit different degrees of attenuation of neurovirulence. The management of ACV- or PCV-resistant HSV infections includes the use of the pyrophosphate analogue foscarnet and the nucleotide analogue cidofovir. There is a need to develop new antiherpetic compounds with different mechanisms of action.

Granulocyte transfusions in the G-CSF era. Where do we stand?

The efficacy of granulocytes transfusions (GTX) in either the prevention or treatment of neutropenic sepsis has been a controversial issue. Early studies employing steroid mobilised GTX showed variable, dose-dependent results and significant pulmonary toxicity was reported. With the introduction of the recombinant myeloid growth factor, granulocyte-colony stimulating factor (G-CSF), the quantity of granulocytes that could be harvested was substantially increased leading to renewed interest in the clinical application of GTX. The administration of G-CSF to normal donors leads to significantly higher pre-harvest neutrophil counts and consequently larger granulocyte harvests. Infusion of G-CSF stimulated GTX results in measurable increases in the recipients' neutrophil count and may reduce the duration and severity of neutropenia. However, the efficacy of these GTX in treating or preventing established neutropenic sepsis remains to be established in prospective controlled clinical trials.

Infectious complications after allogeneic stem cell transplantation: incidence in matched-related and matched-unrelated transplant settings

BACKGROUND

Bacterial, viral, and fungal pathogens frequently cause severe, life-threatening infections in immunocompromised patients after allogeneic hematopoietic stem cell transplantation (SCT).

OBJECTIVE

To compare the frequency of infections in patients with matched-related (Group A) or with human leukocyte antigen (HLA)-matched-unrelated donors (Group B).

PATIENTS AND METHODS

Patients treated at our transplantation unit between April 2004 and April 2005 were enrolled into this analysis. Documentation comprised demographic data, conditioning treatment, stem cell source, clinical course, as well as microbiological and clinical data and mortality.

RESULTS

We analyzed 59 patients, 22 in Group A and 37 in Group B. Both groups were well balanced regarding demographic data. Diagnoses were acute myeloid leukemia (30 of 59 patients, 50.8%), multiple myeloma (15.2%), acute lymphoblastic leukemia (11.9%), and chronic myeloid leukemia (10.2%). Patients in Group A developed infections in 95.5% of the cases compared with 97.3% in patients in Group B. Most frequently detected pathogens were Staphylococcus species, human herpesvirus-6, and Epstein-Barr virus. Three proven fungal infections were detected in Group A compared with 9 proven fungal infections in Group B. Lung infiltrations were observed in equivalent incidence in both groups. Two years after transplantation, 55.9% of patients were alive (Group A: 68.2%; Group B: 48.6%, not significant).

CONCLUSION

Allogeneic SCT from HLA-matched-unrelated donors does not have a higher infection risk than patients transplanted from matched-related donors.

Blood stream infections in allogeneic hematopoietic stem cell transplant recipients: reemergence of Gram-negative rods and increasing antibiotic resistance

Blood stream infections (BSI) are a well-known cause of morbidity and mortality in hematopoietic stem cell transplant (HSCT) patients. The aim of this study was to analyze etiology and microbial resistance of BSI in patients undergoing allogeneic HSCT in a single center over a 4-year period (2004-2007). There were 168 episodes of BSI in 132 patients (median 10 days after HSCT) and 182 pathogens were isolated. Gram-positive bacteria (GPB) accounted for 57% of 182 isolates. Gram-negative rods (GNR) for 37% and fungi for 6%. All patients received routine fluoroquinolone prophylaxis. There was a significant decrease in GPB/GNR ratio over time, from 2.4 in 2004 to 1 in 2007 (P = .043). Among GPB, staphylococci decreased from 37 of 68 (64%) in 2004-2005 to 8 of 35 (23%) in 2006-2007 (P < .002). The Enterococcus faecalis/E. faecium ratio decreased from 4.5 in 2004 to 0.33 in 2007 (P = .006), whereas the total number of enterococcal strains per year did not change. The incidence of Escherichia coli among GNR increased from 3 of 15 (20%) in 2004 to 13 of 21 (62%) in 2007 (P = .003). Fluoroquinolone-resistance was common, both among GPB and GNR (81% and 74%, respectively). Mortality rate at 7 days after BSI was 11% (19 of 168), reaching 39% for Pseudomonas aeruginosa BSI (7 of 18). BSI remains a frequent and potentially life-threatening complication of allogeneic HSCT, the causative organism influencing 7- and 30-day mortality rate. BSI etiology may change rapidly, requiring implementation of new empirical-therapy schemes.

Successful treatment of multi-resistant Pseudomonas aeruginosa osteomyelitis after allogeneic bone marrow transplantation with a combination of colistin and tigecycline

A case of osteomyelitis caused by multidrug-resistant Pseudomonas aeruginosa is reported in a patient who underwent allogeneic bone marrow transplantation for acute lymphoblastic leukaemia. The patient was successfully treated by prolonged administration of a full dose of colistin and tigecycline, and surgical curettage with the positioning of resorbable calcium sulfate pellets loaded with colistin.

Risk factors for fatal infectious complications developing late after allogeneic stem cell transplantation

Infectious complications remain a major problem contributing to significant mortality after hematopoietic allogeneic stem cell transplantation (HSCT). Few studies have previously analyzed mortality due to late infections. Forty-four patients dying from an infectious complication were identified from a cohort of 688 consecutive patients surviving more than 6 months without relapse. A control group of 162 patients was selected using the year of HSCT as the matching criterion. Out of 44 patients, 30 (68%) died from pneumonia, 7/44 (16%) from sepsis, 5/44 (11%) from central nervous system infection and 2/44 (4.5%) from disseminated varicella. The cumulative incidences of different types of infection were 1.6% for viral, 1.5% for bacterial and 1.3% for fungal infections and 0.15% for Pneumocystis jirovecii pneumonia. The majority (66%) of the lethal infections occurred within 18 months after HSCT. Acute GVHD (relative risk (RR): 7.19, P<0.0001), chronic GVHD (RR: 6.49, P<0.001), CMV infection (RR: 4.69, P=0.001), mismatched or unrelated donor (RR: 3.86, P=0.004) and TBI (RR: 2.65, P=0.047) were independent risk factors of dying from a late infection. In conclusion, infections occurring later than 6 months after HSCT are important contributors to late non-relapse mortality after HSCT. CMV infection or acute GVHD markedly increase the risk.

DNA Polymerase Mutations in Drug-Resistant Herpes Simplex Virus Mutants Determine In Vivo Neurovirulence and Drug-Enzyme Interactions

Mutations in the thymidine kinase and DNA polymerase genes of herpes simplex virus (HSV) might confer resistance to antiviral drugs, particularly in immunocompromised patients who suffer from chronic and/or disseminated lesions. The patterns of cross-resistance and neurovirulence in mice of several DNA polymerase mutants selected under pressure of foscarnet (PFA) and different acyclic nucleoside phosphonates (ANPs), including ( S)-3-hydroxy-2-phosphonylmethoxypropyl (HPMP) derivatives of adenine (HPMPA) and cytosine (HPMPC, cidofovir) and 2-phosphonylmethoxyethyl (PME) derivatives of adenine (PMEA) and 2,6-diaminopurine (PMEDAP), were investigated. The mutants were derived from the HSV-1 strain KOS following either single or multiple steps of selection with PFA (V714M, A719V, S724N and T821M), PMEA (S724N, L802F and R959H), PMEDAP (Q618H, S724N, S724N+D1070N), HPMPC (V573M, R700M and K960R) or HPMPA (W998L, L1007M and I1028T). These amino acid substitutions were located in different subdomains of the HSV-1 DNA polymerase, either in conserved or non-conserved regions. The sensitivity of the mutants to a new class of ANPs, the 6-(2-[phosphonomethoxy]alkoxy)pyrimidines HPMPO-DAPy and PMEO-DAPy, was investigated. Cross-resistance between the HPMP derivatives and HPMPO-DAPy, on the one hand, and between the PME derivatives and PMEO-DAPy, on the other hand, was observed. Different degrees of cross-resistance between PME derivatives, PMEO-DAPy, PFA and acyclovir were noticed. The mutants ranged from exhibiting near wild-type neurovirulence (V714M, A719V, S724N and L1007M) to significant attenuation (Q618H, S724N+D1070N, L802F, R700M, K960R, W998L and I1028T) or higher levels of attenuation (V573M). It appears that drug-resistant mutants arising under the pressure of HPMP derivatives have the lowest levels of neurovirulence.

Blood stream infection after hematopoietic stem cell transplantation is associated with increased mortality

Blood stream infection (BSI) is a serious complication of hematopoietic stem cell transplantation (HSCT). The aim of this retrospective cohort analysis was to describe BSI after HSCT, and to assess the predictors and outcomes of BSI after HSCT using multivariable modeling. Of the 243 subjects transplanted, 56% received allogeneic HSCT and 106 (43.6%) developed BSI. Of the 185 isolates, 68% were Gram-positive cocci, 21% were Gram-negative bacilli (GNR) and 11% were fungi. Type of allogeneic HSCT was an independent risk factor for BSI (hazard ratio (HR) 3.26, 95% confidence interval (CI) 1.50, 7.07, P = 0.01), as was the degree of HLA matching (HR 1.84, 95% CI 1.00, 3.37, P = 0.05). BSI was a significant independent predictor of mortality after HSCT (HR 1.79, 95% CI 1.18, 2.73, P = 0.007), after adjusting for acute graft-versus-host disease (GVHD) and allogeneic HSCT (both predicting death < or = 3 months after HSCT). In contrast to the effects of acute GVHD and allogeneic HSCT, the effect of BSI was evident throughout the post-HSCT period. GNR BSI and vancomycin-resistant enterococcal BSI also were significantly associated with death. We concluded that BSI is a common complication of HSCT associated with increased mortality throughout the post-HSCT period.

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.

Severe infections after unrelated donor allogeneic hematopoietic stem cell transplantation in adults: comparison of cord blood transplantation with peripheral blood and bone marrow transplantation

We evaluated the occurrence of severe infections in 192 consecutive adult recipients of volunteer unrelated donor allogeneic hematopoietic stem cell transplants, with a detailed analysis of severe infections after receipt of cord blood transplants (CBTs; n = 48) or bone marrow transplants (BMTs)/peripheral blood stem cell transplants (PBSCTs; n = 144). At a 3-year median follow-up, CBT recipients had a higher risk of developing any severe infection (85% versus 69% in BMT/PBSCT recipients, P < .01). CBT recipients had a higher incidence of severe bacterial infections before day +100, but at 3 years the risks of these and other infections were similar in the CBT and BMT/PBSCT groups. In addition, the 100-day and 3-year incidences of infection-related mortality (IRM) did not differ between groups (P = .2 and .5, respectively). In multivariate analysis, the most significant risk factor for IRM in all 192 patients was monocytopenia (.2 x 10(9)/L). In CBT recipients, only neutropenia (.2 x 10(9)/L) on day +30 and low nucleated cell dose infusion (< 2 x 10(7)/kg) showed a trend for increased IRM (P = .05 in both cases). Stem cell source had no effect on day +100 or 3-year nonrelapse mortality (NRM), cytomegalovirus infection, cytomegalovirus disease (7% versus 6%), or overall survival (36% versus 39%, respectively). The number of mismatches in HLA (A, B, and DRB1) had no effect on any outcome in CBT recipients. In contrast, in the BMT/PBSCT group, the presence of any mismatch by low or high-resolution HLA typing (A, B, C, and DRB1) increased NRM and decreased overall survival (P < .01). IRM was the primary or secondary cause of death in 61% and 59% of CBT and BMT/PBSCT recipients who died, respectively. Our results confirm the relevance of severe infectious complications as source of severe morbidity and NRM after volunteer unrelated donor hematopoietic stem cell transplantation in adults, but suggest that CBT recipients have a similar risk of dying from an infection if an accurate selection of a cord blood unit is done.

Preparations for unrelated donor transplantation

This mini-review briefly describes some of the issues that are important for a transplant physician preparing a patient for an unrelated donor (UD) stem cell transplant. It is primarily directed at referring hemato-oncologists and trainees in transplantation and aims to provide them with the information they require to deal with these patients appropriately and efficiently. It discusses search strategies, the need for urgency and early identification of the major problems that will determine the outcome of the transplant. Excellent communication with the histocompatibility and immunogenetics laboratory and the referring physician are emphasized. Many of the recommendations are derived from personal experience; there is a need for more of an evidence base to aid decision-making.

Surveillance of nosocomial infections in paediatric recipients of bone marrow or peripheral blood stem cell transplantation during neutropenia, compared with adult recipients

The aim of this prospective study was to analyse the incidence of nosocomial infections (NIs) during neutropenia after haematopoietic stem cell transplantation (HSCT) in paediatric and adult patients. Diagnosis of NI followed the modified surveillance protocol of the German National Reference Centre for Surveillance of NIs. During the 24-month study period, 38 and 39 transplantations were performed in paediatric and adult patients, respectively. Eighty percent and 92% of the paediatric and adult patients, respectively, underwent allogenic HSCT. In total, 1156 neutropenic days were documented. The incidence of NI during neutropenia in all recorded cases was 38.9 NI per 1000 days, without significant difference between the groups. No difference was found in the incidence rates of pneumonia, while there was a trend towards a higher incidence of bloodstream infection in adult patients. Significantly more episodes of fever of unknown origin were found in paediatric than adult patients. Pathogens were isolated in 19 of 45 cases of NI. Of the clinically documented infections, Gram-positive organisms were isolated in 79%, Gram-negative organisms were isolated in 16% and fungi were isolated in 5%. Surveillance of NI is an effective instrument to control the quality of health care. It should focus on device-associated infections or specific high-risk targets such as nosocomial pneumonia.

Requirement for neutralizing antibodies to control bone marrow transplantation-associated persistent viral infection and to reduce immunopathology

Bone marrow transplantation (BMT) is commonly used in the treatment of leukemia, however its therapeutic application is partly limited by the high incidence of associated opportunistic infections. We modeled this clinical situation by infecting mice that underwent BMT with lymphocytic choriomeningitis virus (LCMV) and investigated the potential of immunotherapeutic strategies to counter such infections. All mice that received BMT survived LCMV infection and developed a virus carrier status. Immunotherapy by adoptive transfer of naive splenocytes protected against low (200 PFU), but not high (2 x 10(6) PFU), doses of LCMV. Attempts to control infection of high viral titers using strongly elevated frequencies of activated LCMV-specific T cells failed to control virus and resulted in immunopathology and death. In contrast, virus neutralizing Abs combined with naive splenocytes were able to efficiently control high-dose LCMV infection without associated side effects. Thus, cell transfer combined with neutralizing Abs represented the most effective means of controlling BMT-associated opportunistic viral infection in our in vivo model. These data underscore the in vivo efficacy and immunopathological "safety" of neutralizing antibodies.

Improving immune reconstitution while preventing GvHD in allogeneic stem cell transplantation

Allogeneic hematopoietic stem cell transplantation (HSCT) is the treatment of choice for many hematologic malignancies and inherited disorders of the hematopoietic system. Ex vivo T-cell depletion (TCD) of the graft and post-transplantation immunosuppression efficiently prevents the development of GvHD in no- MHC-identical settings. However, the consequence of these non-specific strategies is a long-lasting immunodeficiency associated with increased incidence of disease relapse, graft rejection and reactivation of viral infections. Donor lymphocyte infusion, which is used for treating leukemic relapse after allogeneic HSCT, can result in severe GvHD. Several strategies are being optimized specifically to inactivate anti-host T cells while preserving anti-leukemic or anti-microbial immunocompetence. Based on the ex vivo or in vivo elimination of anti-host T cells, or on the modulation of their anti-host activity, these approaches, which have been explored extensively in pre-clinical studies and tested in some preliminary clinical trials, are discussed in this paper.

Hospital-wide prospective mandatory surveillance of invasive aspergillosis in a French teaching hospital (2000-2002)

A multidisciplinary working group devoted to epidemiological surveillance of invasive aspergillosis (IA) was created in January 2000 in Grenoble University Hospital. This article presents the results of a three-year IA surveillance. The multidisciplinary working group surveyed all hospitalized patients, and the mycology laboratory detected most suspected IA cases. Cases were reviewed monthly by the Aspergillosis Committee, and were classified according to international consensus criteria. Possible nosocomial acquisition was determined. Among the 490 alerts, 74 IA cases were observed: six proven cases (8%), 36 (49%) probable cases and 32 (43%) possible cases. The incidence was 4.4 (95% CI 3.4-5.4) IA/100 000 patient-days. Among the proven and probable IA cases, we observed 10 nosocomial cases and six cases of undetermined origin. No cases were noted in the protected rooms in the haematology unit. Only one cluster of cases (three nosocomial cases) was detected in the haematology unit. Forty-three percent of cases (N=32) were hospitalized in the haematology unit, and all other cases were hospitalized elsewhere. This three-year survey found a high rate of non-nosocomial IA cases and a high frequency of IA cases hospitalized in units other than haematology. Thus, this study shows the importance of IA surveillance in haematology units and all high-risk units.

Pre- and post-engraftment bloodstream infection rates and associated mortality in allogeneic hematopoietic stem cell transplant recipients

We report on bloodstream infection (BSI) rates, risk factors, and outcome in a cohort of 298 adult and pediatric hematopoietic stem cell transplantation (HSCT) recipients at Memorial Sloan-Kettering Hospital from September 1999 through June 2003. Methods. Prospective surveillance study. BSI rates are reported per 10,000 HSCT days. Date of engraftment is defined as the first of at least 3 consecutive dates of absolute neutrophil count >500/mm(3) after stem cell infusion. BSI severity grades: severe (intravenous antibiotics), life threatening (sepsis), or fatal (caused or contributed to death). Results. The incidence of pre- and post-engraftment BSI was 22% and 19.5%, respectively. Pre-engraftment highest rates were observed for viridans streptococci (58), Enterobacteriaceae (39), and Enterococcus faecium (34). Post-engraftment rates ranged from 0.2 to 2.9 without any predominant pathogen. In multivariate analyses, pre-engraftment BSI was associated with diagnosis of chronic myelogenous leukemia, age >18 years and peripheral blood stem cell graft; post-engraftment BSI was associated with acute graft-versus-host disease, neutropenia, and liver or kidney dysfunction. Attributable mortality was 12.5% and 1.7% for pre- and post-engraftment BSI, respectively. BSI fatality rates were 24% for viridans streptococci, 8% for E. faecium, 11% for Staphylococcus aureus, and 67% for Candida. Conclusions. Pre-engraftment BSI, especially by viridans streptococci and E. faecium, was associated with substantial attributable mortality. Post-engraftment BSI was a marker of post-transplant complications and rarely the primary cause of death.

Survey of acyclovir-resistant herpes simplex virus in the Netherlands: prevalence and characterization

BACKGROUND

Widespread and frequent use of acyclovir (ACV) for treatment, suppressive therapy and prophylaxis of herpes simplex virus (HSV) infections and its over the counter availability may be associated with emergence of HSV resistance.

OBJECTIVES

To determine the prevalence of ACV-resistant HSV isolates in different patient groups between 1999 and 2002 in the Netherlands.

STUDY DESIGN

A total of 542 isolates, 410 HSV-1 and 132 HSV-2, from 496 patients were screened for reduced susceptibility to ACV. A newly developed ELVIRA HSV screening assay was used that allowed a high throughput screening. The genotypic analysis of the HSV thymidine kinase gene was performed to identify resistance-associated mutations.

RESULTS

Thirteen isolates, 8 HSV-1 and 5 HSV-2, from 10 patients (2%) were found resistant to ACV. A single ACV-resistant strain was identified among isolates from 368 immunocompetent patients (0.27%; 95% confidence interval [CI], 0.007%-1.5%), whereas in nine isolates from 128 immunocompromised patients resistant HSV was identified (7%; 95% CI, 3.26%-12.93%). The highest frequency of ACV-resistant HSV was associated with bone marrow transplantation: four patients out of 28 (14.3%) shed resistant virus. In addition, resistant virus was obtained from two HIV-positive patients, one patient with a hematological malignancy and two patients on immunosuppressive drugs. Further testing showed that none of the isolates was resistant to foscarnet. Several new mutations were identified in the thymidine kinase gene of these resistant isolates, and their effect on ACV-resistance is discussed.

CONCLUSIONS

Our study shows that the prevalence of ACV resistance is low in immunocompetent patients (0.27%), whereas ACV-resistant HSV infections occur relatively frequently in immunocompromised patients (7%; P < 0.0001). This emphasizes the need for drug susceptibility monitoring of HSV infections in immunocompromised patients with persisting infections despite antiviral therapy.

Surveillance of nosocomial sepsis and pneumonia in patients with a bone marrow or peripheral blood stem cell transplant: a multicenter project

BACKGROUND

For surveillance of nosocomial bloodstream infections (BSIs) and pneumonia during neutropenia in adult patients who have undergone bone marrow transplantation (BMT) or peripheral blood stem cell transplantation (PBSCT), a multicenter study--the Hospital Infection Surveillance System for Patients with Hematologic/Oncologic Malignancies (ONKO-KISS)--was initiated in Germany in 2000.

METHODS

Nosocomial infections were identified in neutropenic patients by means of Centers for Disease Control and Prevention definitions for laboratory-confirmed BSI and modified criteria for pneumonia.

RESULTS

During the first 38-month period of the study (i.e., through December 2003), a total of 1899 patients associated with 28,273 neutropenic days were investigated. Of these, 1173 (62%) had undergone allogeneic and 726 (38%) had undergone autologous BMT or PBSCT. The mean duration of neutropenia was 14.9 days (9.6 and 18.1 days after autologous and allogeneic transplantation, respectively). Overall, 395 BSIs and 168 cases of pneumonia were identified. The pooled mean site-specific incidence density per 1000 neutropenic days was 14.0 for BSI (12.4 and 18.9 for the allogeneic and autologous transplantation groups, respectively) and 5.9 for pneumonia (6.1 and 5.6 in the allogeneic and autologous transplantation groups, respectively). After allogeneic transplantation, 22.4 BSIs per 100 patients and 11.0 cases of pneumonia per 100 patients occurred, whereas 18.2 BSIs per 100 patients and 5.4 cases of pneumonia per 100 patients occurred after autologous transplantation. The majority (57%) of pathogens associated with BSI were coagulase-negative staphylococci.

CONCLUSIONS

The ongoing ONKO-KISS project provides unprecedented reference data about the incidence of pneumonia and sepsis among BMT recipients and PBSCT recipients in Germany. These data will be used for further evaluation of the impact of hygiene measures and therapeutic regimens for these patients.

Nosocomial nontyphoidal salmonellosis after antineoplastic chemotherapy: reactivation of asymptomatic colonization?

An increased frequency of nontyphoidal salmonellosis is well established in cancer patients, but it is unclear whether this represents increased susceptibility to exogenous infection or opportunistic, endogenous reactivation of asymptomatic carriage. In a retrospective study, a simple case definition was used to identify the probable presence of reactivation salmonellosis in five cancer patients between 1996 and 2002. Reactivation salmonellosis was defined as the development of nosocomial diarrhea >72 h after admission and following the administration of antineoplastic chemotherapy in an HIV-seronegative cancer patient who was asymptomatic on admission, in the absence of epidemiological evidence of a nosocomial outbreak. Primary salmonellosis associated with unrecognized nosocomial transmission or community acquisition and an unusually prolonged incubation period could not entirely be ruled out. During the same time period, another opportunistic infection, Pneumocystis pneumonia, was diagnosed in six cancer patients. Presumably, asymptomatic intestinal Salmonella colonization was converted to invasive infection by chemotherapy-associated intestinal mucosal damage and altered innate immune mechanisms. According to published guidelines, stool specimens from patients hospitalized for longer than 72 h should be rejected unless the patient is neutropenic or >or=65 years old with significant comorbidity. However, in this study neutropenia was present in only one patient, and four patients were <65 years old. Guidelines should thus be revised in order not to reject stool culture specimens from such patients. In cancer patients, nosocomial salmonellosis can occur as a chemotherapy-triggered opportunistic reactivation infection that may be similar in frequency to Pneumocystis pneumonia.

Sepsis associated with immunosuppressive medications: an evidence-based review

OBJECTIVE

In 2003, critical care and infectious disease experts representing 11 international organizations developed management guidelines for sepsis associated with immunosuppressive medications that would be of practical use for the bedside clinician, under the auspices of the Surviving Sepsis Campaign, an international effort to increase awareness and improve outcome in severe sepsis.

DESIGN

The process included a modified Delphi method, a consensus conference, several subsequent smaller meetings of subgroups and key individuals, teleconferences, and electronic-based discussion among subgroups and among the entire committee.

METHODS

The modified Delphi methodology used for grading recommendations built on a 2001 publication sponsored by the International Sepsis Forum. We undertook a systematic review of the literature graded along five levels to create recommendation grades from A to E, with A being the highest grade. Pediatric considerations to contrast adult and pediatric management are in the article by Parker et al. on p. S591.

CONCLUSION

Immunosuppressed patients, by definition, are susceptible to a wider spectrum of infectious agents than immunologically normal patients and, thus, require a broader spectrum antimicrobial regimen when they present with sepsis or septic shock. Special expertise managing immunosuppressed patient populations is needed to predict and establish the correct diagnosis and to choose appropriate empiric and specific agents and maximize the likelihood that patients will survive these microbial challenges.

Adenovirus infections in stem cell transplant recipients: recent developments in understanding of pathogenesis, diagnosis and management

Adenovirus is increasingly recognized as an important pathogen in stem cell transplant recipients, reflecting increased awareness about the virus, together with changes in transplant practice such as the performance of more high-risk transplants, and improvements in diagnostic methods. In retrospective studies, the reported incidence of adenovirus infections ranged between 4-20% with a similar variation in the proportion of patients developing invasive disease. In contrast, the incidence of adenovirus infection varies between 20-30% in recent prospective studies on T-cell depleted or mismatched allografts and about 30-40% of these patients develop invasive disease. These prospective studies have established a relationship between the risk of invasive adenovirus disease and a number of factors such as the extent of T-cell depletion, the intensity of immunosuppressive therapy and the kinetics of lymphocyte recovery post-transplant. Polymerase chain reaction (PCR) assays to detect adenovirus DNA in peripheral blood have shown a strong correlation between viremia and the risk of disseminated adenovirus disease. These developments have led to the possibility of a preemptive antiviral treatment strategy for asymptomatic adenovirus infections. In addition, a better understanding of the interactions between adenovirus and host immune system in the post-transplant setting might enable development of effective immunotherapeutic strategies against adenovirus infections.

Influence of cytomegalovirus (CMV) sero-positivity on CMV infection, lymphocyte recovery and non-CMV infections following T-cell-depleted allogeneic stem cell transplantation: a comparison between two T-cell depletion regimens

We compared the incidence and outcome of preemptively treated cytomegalovirus (CMV) infection, lymphocyte recovery and non-CMV infections between two different TCD modalities, one employing CD34+ selection and T-cell add-back (TCAB), preceded by Campath-1H in vivo (CD34+/TCAB group, n=29), and the other using grafts incubated with Campath-1H in vitro (Campath-1H in vitro group, n=32). The probabilities of CMV reactivation and recurrence were 67 and 83.6% in the CD34+/TCAB group and 42.9 and 20% in the Campath-1H group (P=0.07 and 0.02). Donor sero-positivity reduced CMV reactivation in the Campath-1H group, but not in the CD34+/TCAB group. The durations of positive PCR/antigenemia positivity and antiviral therapy were also significantly longer in the CD34+/TCAB group. However, only two patients developed CMV disease in each group. The mean absolute lymphocyte counts (x 10(9)/l) at 30 days (0.27 vs 0.4, P=0.03) and 100 days (0.77 vs 1.4, P=0.01) were significantly lower in the CD34+/TCAB group along with a higher incidence of non-CMV infections in CMV at-risk patients, but not in the CMV low-risk group. These findings suggest that the modality of TCD should be tailored according to the CMV risk status, and CMV sero-positive patients should receive a less extensively T-cell-depleted graft and a CMV sero-positive graft if possible.

HSV excretion after bone marrow transplantation: a 4-year survey

BACKGROUND

Herpes simplex virus (HSV) oral excretions are common after bone marrow transplantation (BMT).

OBJECTIVE

We report a 4-year systematic survey of HSV excretions in an adult population who underwent BMT (289 transplantations).

STUDY DESIGN

Patients received either intravenous ACV treatment when mucositis occurred or systematic intravenous ACV prophylaxis from initiation of the BMT conditioning until the end of aplasia. All patients were followed up for HSV excretions.

RESULTS

Twenty-eight patients (9.7%) excreted HSV. The occurrence of HSV excretions was similar in both allogeneic and autologous transplant patients. The incidence was significantly lower when ACV was systematically used after transplantation (2.5%) compared to when ACV was implemented for mucositis (12%). ACV-resistant HSV was detected in three patients who received allogeneic transplantation, representing 27% of allogeneic recipients excreting HSV.

CONCLUSION

HSV infection prophylaxis with high dose of intravenous ACV resulted in a decreased incidence of HSV excretion. Nevertheless, the risk of emergence of ACV resistance, especially among allogeneic transplant patients, appears to be identical whatever the route and dose of ACV prophylaxis.

Bacteremia after hematopoietic stem cell transplantation: incidence and predictive value of surveillance cultures

We studied 622 transplants undertaken between 1982 and 2001 to: (1) determine the incidence, timing and etiology of bacteremias, and (2) examine the ability of routine surveillance cultures to predict bacteremias. A total of 404 episodes (0.65 episode per patient) occurred in 248 patients, due to coagulase-negative staphylococci (n=171, 42%), Gram-negative bacteria (n=129, 32%), streptococci (n=48, 12%), other Gram-positive bacteria (n=33, 8%), anaerobes (n=9, 2%) and fungi (n=14, 3%). Bacteremias were more frequent in allogeneic (0.96 episode/patient) compared to autologous (0.44) transplants (P<0.0001). The overall incidence decreased from 0.92 episode/patient until 1990 to 0.66 in 1991-1996 and 0.55 in 1997-2001 (P<0.0001), but this was only observed in autologous transplants. Among them, 212 (53%) occurred before hospital discharge and 192 (47%) thereafter. This proportion was lower for coagulase-negative staphylococci, other Gram-positive bacteria and Gram-negative bacteria compared to other agents (P=0.001). In 50% of the cases, the agent responsible for the bacteremic episode was present in routine surveillance cultures previously.

IN CONCLUSION

(1) bacteremias remain a frequent complication, particularly in allogeneic transplantation, even long after hospital discharge; (2) routine surveillance cultures can predict bacteremias in 50% of the cases, but the practical impact of this observation is limited in view of the costs.

Gram-negative bacteraemia (GNB) after 428 unrelated donor bone marrow transplants (UD-BMT): risk factors, prophylaxis, therapy and outcome

Gram-negative infection is an important cause of morbidity and mortality after unrelated donor-bone marrow transplantation (UD-BMT). We performed a retrospective case-control study to examine the risk factors, prophylaxis, therapy and outcome of Gram-negative bacteraemia (GNB) in 428 patients undergoing UD-BMT. The incidence of GNB was 3.6% in children and 19% in adults. Of the adults, 11% developed GNB >60 days post UD-BMT. Predisposing risk factors for GNB included 'high-risk' disease status, chronic graft-versus-host disease and use of systemic steroids. Fever, a raised C-reactive protein (CRP) and hypotension were common findings at presentation. Patients were routinely given prophylactic ciprofloxacin: resistance to this antibiotic was seen in 33% of isolates. We identified an age-matched control group undergoing UD-BMT over the same time period as the study group. Gram-positive bacteraemia was significantly more common in cases than controls. Mortality from GNB was 17% in children and 24% in adults. We conclude that GNB is a common complication of UD-BMT with a high associated mortality. Patients should be educated further to present rapidly with symptoms suggestive of infection.

Infectious complications following nonmyeloablative allogeneic hematopoietic stem cell transplantation

Nonmyeloablative hematopoietic stem cell transplantation (NST) has been explored in hematological malignancies and solid tumors in an attempt to minimize treatment-related toxicity. Whether this approach is associated with reduced risk of infectious complications is unclear. The aim of the current study was to evaluate the infectious complications in a series of 32 consecutive adult patients who received NST at our institution. Peripheral blood stem cell grafts (n=30) or marrow grafts (n=2) were infused from human leukocyte antibody (HLA)-matched sibling (n=30), partially matched related (n=1), or unrelated (n=1) donors. Neutropenia developed in two-thirds of patients and lasted 16 days. Acute graft-versus-host disease (GVHD) grade II to IV was observed in 25% of patients, whereas 35% of patients had signs of extensive chronic GVHD. Twenty-two patients (69%) had at least one significant infectious episode. Bacteremia occurred in 19% of patients (n=5 gram-positive, n=1 gram-negative microorganisms). Cytomegalovirus (CMV) infection was observed in 10 out of 28 (36%) evaluable patients; 4 of these had recurrent or persistent CMV antigenemia requiring a second-line treatment, but eventually the viremia cleared. No patients experienced CMV disease. Fungal infections were documented in five (16%) patients, comprising invasive fungal infections in two cases and mucosal fungal infections in three. Four patients died of transplant-related causes, and three of these died before day +100. Infection was considered the primary cause of death in one patient (pulmonary aspergillosis) and contributed to death in another two. The actuarial probability of nonrelapse mortality at 100 days was 10% (95% confidence interval, 3-26%). Our preliminary results suggest that NST is associated to a low incidence of bacteremia or fungal and viral infections. Whether these findings would translate into an improved overall survival needs to be confirmed in larger prospective studies.

The use of stimulated granulocyte transfusions to prevent recurrence of past severe infections after allogeneic stem cell transplantation

The predictable neutropenia that follows allogeneic stem cell transplantation (ASCT) may be associated with recurrence of previous life-threatening infection. We describe nine patients with either previous invasive aspergillosis (IA) or considered to be at high risk of developing IA who underwent ASCT with prophylactic granulocyte transfusions. The study group, when compared with a control group, had a significant reduction in the incidence and duration of fevers (P < 0.05) and maximum C-reactive protein (P < 0.05). There were significantly fewer days of neutropenia (P < 0.05). There was also radiological improvement of pulmonary infiltrates in four out of seven assessable patients. No serious toxicity was encountered in donors or recipients. We conclude that prophylactic granulocyte donations can be given safely, and that they significantly reduce the number of days of neutropenia. Further investigation is warranted to determine whether granulocyte donations can prevent the recurrence of IA in patients at risk of fungal infection.

Respiratory tract viral infections in bone marrow transplant patients

BACKGROUND

Community respiratory viruses such as respiratory syncytial virus (RSV), adenovirus, influenza A, influenza B, and the parainfluenza group are frequent causes of respiratory disease in bone marrow transplant (BMT) patients.

MATERIAL AND METHODS

During the period from March 1993 to August 1999, 810 samples of respiratory secretions, nasopharyngeal aspirate (NPA) or bronchoalveolar lavage (BAL), from 722 patients with upper respiratory infections symptoms at the BMT unit of the Federal University in the state of Paraná, Brazil were evaluated for respiratory virus infection.

RESULTS

One hundred thirty-six (17%) samples were reactive in 62 patients. RSV was found in 30 of 62 (48%), influenza A in 14 of 62 (23%), influenza B in 9 of 62 (15%), parainfluenza group in 7 of 62 (11%), and adenovirus in 2 of 62 (3%) infected patients. The most frequent clinical manifestations were cough and fever. Pneumonia occurred in 19 of 62 (31%) cases. The mortality rate was 23 of 62 (37%), being higher among patients infected with adenovirus and influenza A.

CONCLUSIONS

Infections in BMT patients occurred during the outbreak period of these viruses in the community, highlighting the need to establish surveillance measures in units with immunocompromised patients in addition to the development of sensitive and rapid diagnostic tests for the detection of these viruses in patients with respiratory symptoms.

Recommendations for immunizations in stem cell transplantation

Investigations over the past decade have documented that there is a decline in immunity to vaccine preventable diseases in many SCT recipients. The majority of immunization studies conducted in SCT recipients to date support the use of multi-dose regimens for most protein and polysaccharide-conjugate vaccine antigens. The consensus immunization schedule recommended by ACIP/IDSA/ASBMT provides guidance for centers to utilize available vaccines in their SCT populations. With the exception of pneumococcal disease, a schedule beginning at 12 months after SCT is reasonable given the low incidence of disease in HSCT recipients for most of the recommended vaccines and improved immune reconstitution in most recipients by one year post transplant. SCT recipients respond poorly to unconjugated pneumococcal polysaccharide vaccine and the development of polysaccharide-protein conjugate vaccines against S. pneumoniae holds promise to impact potentially on clinical disease in this population. In addition, the strategy of donor immunization may also be effective in eliciting early protective immune responses to vaccine antigens. Future challenges will be the development of safe and effective vaccines against the viral pathogens responsible for considerable morbidity and mortality after SCT.

Procalcitonin, C-reactive protein, and endotoxin after bone marrow transplantation: identification of children at high risk of morbidity and mortality from sepsis

We prospectively evaluated the capacity of serum procalcitonin (PCT), compared with serum levels of C-reactive protein (CRP) and endotoxin, to identify children at high risk for mortality from sepsis after BMT. Of 47 pediatric bone marrow transplantation patients studied, 22 had an uneventful course post-transplant (Group 1), 17 survived at least one septic event (Group 2), and eight died from multiorgan failure (MOF) following septic shock (Group 3). Median concentrations of PCT over the course of the study were 1.3, 15.2, and 102.8 ng/ml, respectively, in each of the three groups (P<0.002 for each comparison). Median concentrations of CRP were 91, 213, and 260 mg/l, respectively (P<0.001 for Group 1 vs Group 2 and Group 3; P=NS for Group 2 vs Group 3). Median concentrations of endotoxin were 0.21, 0.30, and 0.93 U/l, respectively (P=NS for each comparison). Median concentrations of PCT, in contrast to serum CRP and endotoxin, correlated with the severity of sepsis (8.2 ng/ml in 'sepsis' and 22.3 ng/ml in 'severe sepsis', P=0.028) and provided useful prognostic information during septic episodes.