Katherine M. Knapp

Prospective Surveillance for Invasive Fungal Infections in Hematopoietic Stem Cell Transplant Recipients, 2001–2006: Overview of the Transplant-Associated Infection Surveillance Network (TRANSNET) Database

BACKGROUND The incidence and epidemiology of invasive fungal infections (IFIs), a leading cause of death among hematopoeitic stem cell transplant (HSCT) recipients, are derived mainly from single-institution retrospective studies. METHODS The Transplant Associated Infections Surveillance Network, a network of 23 US transplant centers, prospectively enrolled HSCT recipients with proven and probable IFIs occurring between March 2001 and March 2006. We collected denominator data on all HSCTs preformed at each site and clinical, diagnostic, and outcome information for each IFI case. To estimate trends in IFI, we calculated the 12-month cumulative incidence among 9 sequential subcohorts. RESULTS We identified 983 IFIs among 875 HSCT recipients. The median age of the patients was 49 years; 60% were male. Invasive aspergillosis (43%), invasive candidiasis (28%), and zygomycosis (8%) were the most common IFIs. Fifty-nine percent and 61% of IFIs were recognized within 60 days of neutropenia and graft-versus-host disease, respectively. Median onset of candidiasis and aspergillosis after HSCT was 61 days and 99 days, respectively. Within a cohort of 16,200 HSCT recipients who received their first transplants between March 2001 and September 2005 and were followed up through March 2006, we identified 718 IFIs in 639 persons. Twelve-month cumulative incidences, based on the first IFI, were 7.7 cases per 100 transplants for matched unrelated allogeneic, 8.1 cases per 100 transplants for mismatched-related allogeneic, 5.8 cases per 100 transplants for matched-related allogeneic, and 1.2 cases per 100 transplants for autologous HSCT. CONCLUSIONS In this national prospective surveillance study of IFIs in HSCT recipients, the cumulative incidence was highest for aspergillosis, followed by candidiasis. Understanding the epidemiologic trends and burden of IFIs may lead to improved management strategies and study design.

Pediatric Invasive Aspergillosis: A Multicenter Retrospective Analysis of 139 Contemporary Cases

OBJECTIVE. Invasive aspergillosis is a major cause of morbidity and mortality in immunocompromised children. Invasive aspergillosis has been well characterized in adults; however, the incidence and analysis of risk factors, diagnostic tools, treatments, and outcomes have not been well described for a large cohort of pediatric patients. METHODS. We conducted the largest retrospective review of contemporary cases of proven and probable pediatric invasive aspergillosis diagnosed at 6 major medical centers (January 1, 2000, to July 1, 2005). RESULTS. Aspergillus fumigatus was the species most frequently recovered (52.8%) for the 139 patients analyzed. The majority of the children had a malignancy with or without hematopoietic stem cell transplant. Significant risk factors that impacted survival were immunosuppressive therapies and allogeneic stem cell transplant. The most common clinical site of invasive aspergillosis was the lungs (59%), and the most frequent diagnostic radiologic finding was nodules (34.6%). Only 2.2% of children showed the air crescent sign, 11% demonstrated the halo sign, and cavitation was seen in 24.5% of patients. Before the diagnosis of invasive aspergillosis, 43.1% of patients received fluconazole, and 39.2% received liposomal amphotericin B. After the diagnosis of invasive aspergillosis, 57% were treated with a lipid formulation of amphotericin B; however, 45.8% received ≥3 concomitant antifungal agents. Analysis did not show superiority of any 1 antifungal related to overall mortality. A total of 52.5% (73 of 139) died during treatment for invasive aspergillosis. Of all the interventions implemented, surgery was the only independent predictor of survival. CONCLUSIONS. Our analyses revealed common findings between adult and pediatric invasive aspergillosis. However, one key difference is diagnostic radiologic findings. Unlike adults, children frequently do not manifest cavitation or the air crescent or halo signs, and this can significantly impact diagnosis. Immune reconstitution, rather than specific antifungal therapy, was found to be the best predictor of survival.

Etiology and Clinical Course of Febrile Neutropenia in Children with Cancer

Background The etiology, clinical course, and outcome of fever and neutropenia (FN) in children with cancer using the current FN guidelines and diagnostic resources in the United States have not been well described. Patients and Methods Medical records of a randomly selected FN episode per patient during 2004-2005 at a pediatric oncology center were reviewed. Patients were managed as per institutional FN guidelines and blood cultures collected in continuously read BACTEC bottles. Results Of 337 FN episodes, infection was proven in 86 (25%) and probable in 75 (22%). In all, 177 episodes (53%) were judged fever of unknown origin (FUO). Bacteremia accounted for most (41) of the proven bacterial episodes, with viridans streptococci (13), Pseudomonas spp. (6) and Escherichia coli (6) the most frequently isolated organisms. The median time to positivity of blood cultures was 12 hours (range, 5.4-143.7) with 93% positive within 24 hours of incubation. Viral pathogens were identified in 29 (34%) episodes. Compared with other patients, those with FUO had shorter median duration of fever (0.5 vs. 2.0 d; P<0.0001) and hospitalization (3 vs. 6 d; P<0.0001), longer median duration since last chemotherapy (6.0 vs. 4.0 d; P=0.01), and were less likely to have a diagnosis of acute myelogenous leukemia (11% vs. 22%; P=0.009) or develop a clinical complication (5.1% vs. 24.4%; P<0.0001). Conclusions Despite currently available diagnostic resources, the majority of patients with FN have FUO marked by a low rate of clinical complications and no infection-related mortality. Emergence of viridans streptococci as the most common blood isolate has affected FN treatment recommendations. Study findings will help further development of strategies for risk stratified management of fever with neutropenia in pediatric patients.

Virologic and Immunologic Outcomes after 24 Weeks in HIV Type 1-Infected Adolescents Receiving Highly Active Antiretroviral Therapy

BACKGROUND Adolescents represent the fastest growing demographic group of new human immunodeficiency virus (HIV) infections in the United States. At present, there is little information available about their response to therapy. METHODS We studied 120 adolescents infected via high-risk behaviors who began receiving highly active antiretroviral therapy (HAART), to determine their virologic and immunologic response to therapy. RESULTS Subjects were enrolled at 28 sites of the Pediatric Acquired Immunodeficiency Syndrome Clinical Trials Group. After 16-24 weeks of HAART, 59% of subjects had reproducible undetectable virus loads, according to repeat measurements (virologic success). As enumerated by flow-cytometric analysis, increases in levels of CD4 helper cells (both naive and memory) and decreases in levels of CD8 suppressor cells were observed. Partial restoration of some immunologic parameters for patients who did not achieve virologic success was also observed, but to a more limited extent than for adolescents with virologic success. Adherence to HAART was the only predictor of achieving undetectable virus loads. CONCLUSIONS Adolescents have the capacity to improve their immunologic status with HAART. Lower than expected success in virologic control is related to lack of adherence, and efforts to improve treatment outcome must stress measures to assure adherence to medication.

Results from a Prospective, International, Epidemiologic Study of Invasive Candidiasis in Children and Neonates

Background: Candida species are the third most common cause of pediatric health care–associated bloodstream infection in the United States and Europe. To our knowledge, this report from the International Pediatric Fungal Network is the largest prospective, multicenter observational study dedicated to pediatric and neonatal invasive candidiasis. Methods: From 2007 to 2011, we enrolled 196 pediatric and 25 neonatal patients with invasive candidiasis. Results: Non-albicans Candida species predominated in pediatric (56%) and neonatal (52%) age groups, yet Candida albicans was the most common species in both groups. Successful treatment responses were observed in pediatric (76%) and neonatal patients (92%). Infection with Candida parapsilosis led to successful responses in pediatric (92%) and neonatal (100%) patients, whereas infection with Candida glabrata was associated with a lower successful outcome in pediatric patients (55%). The most commonly used primary antifungal therapies for pediatric invasive candidiasis were fluconazole (21%), liposomal amphotericin B (20%) and micafungin (18%). Outcome of pediatric invasive candidiasis was similar in response to polyenes (73%), triazoles (67%) and echinocandins (73%). The most commonly used primary antifungal therapies for neonatal invasive candidiasis were fluconazole (32%), caspofungin (24%) and liposomal amphotericin B (16%) and micafungin (8%). Outcomes of neonatal candidiasis by antifungal class again revealed similar response rates among the classes. Conclusions: We found a predominance of non-albicans Candida infection in children and similar outcomes based on antifungal class used. This international collaborative study sets the foundation for large epidemiologic studies focusing on the unique features of neonatal and pediatric candidiasis and comparative studies of therapeutic interventions in these populations.

Pharmacokinetics and Safety of Caspofungin in Older Infants and Toddlers

ABSTRACT Although information about the efficacy and safety experience with caspofungin at 50 mg/m2 daily is available for children and adolescents, the dosing regimen in infants and toddlers 3 to 24 months of age has yet to be established. We studied the pharmacokinetics and safety of caspofungin at 50 mg/m2 once daily in nine patients 10 to 22 months (median, 13 months) of age with fever and neutropenia who received caspofungin once daily for 2 to 21 (mean, 9.3) days. Plasma caspofungin concentrations were measured by high-performance liquid chromatography assay on days 1 and 4. On day 4, the area under the curve from 0 to 24 h (AUC0-24) was 130.3 μg-h/ml, the peak concentration (C1) was 17.2 μg/ml, and the trough concentration (C24) was 1.6 μg/ml. The day 4 geometric mean ratios (GMRs) and 90% confidence interval (CI) for these parameters in infants/toddlers relative to adults were 1.26 (1.06, 1.50), 1.83 (1.57, 2.14), and 0.81 (0.64, 1.04), respectively. Relative to children (2 to 11 years of age), the day 4 GMRs (and 90% CI) were 1.13 (0.89, 1.44), 1.10 (0.85, 1.42), and 1.12 (0.72, 1.76), respectively. The harmonic mean elimination phase t1/2 in infants/toddlers (8.8 h) was reduced ∼33% relative to adults (13.0 h) but was similar to that in children (8.2 h). Clinical adverse events occurred in seven patients (78%); none were considered drug related. Laboratory adverse events occurred in five patients (56%) and were considered drug related in three (33%). There were no infusion-related events or discontinuations due to toxicity. Caspofungin at 50 mg/m2 daily was well tolerated in infants and toddlers; the AUC and caspofungin C24 were generally comparable to those in adults receiving caspofungin at 50 mg daily.

Galactomannan antigenemia in pediatric oncology patients with invasive aspergillosis.

Background: Diagnosing invasive aspergillosis is difficult but might be improved by detection of circulating galactomannan. Although galactomannan antigenemia has been well studied in the detection of invasive aspergillosis in adult patients, little is known about the expression of circulating galactomannan in immunocompromised children with invasive aspergillosis. Methods: We studied the expression of galactomannan antigen by enzyme immunoassay (EIA) in 990 serum samples from 56 pediatric oncology patients (ages 3 months to 18 years) of whom 17 had proven or probable invasive aspergillosis defined by the European Organization for Research and Treatment of Cancer-Mycoses Study Group criteria. Any sample with a galactomannan EIA Galactomannan index value of ≥0.5 was considered positive. Results: At least 1 serum sample was positive for 11 of 17 pediatric oncology patients (65.7% sensitivity, 95% confidence interval: 38.3–85.7) with invasive aspergillosis. Galactomannan EIA was positive in 99 of 304 samples from patients with proven or probable invasive aspergillosis, and 7 of 686 (1.0%) samples from 39 control subjects resulted in a positive galactomannan EIA result. At least 1 sample tested positive in 5 of the 39 controls (12.8%, 95% confidence interval: 4.3–27.4). No significant association between accuracy and patient age was observed. Among the 7 evaluable galactomannan-positive patients with IA, the galactomannan EIA produced a positive result before clinical or radiographic evidence of infection in 6 cases, with a lead-time to diagnosis ranging from 1 day to 34 days (median: 10 days). In the remaining case, a positive galactomannan was observed on the same day as diagnosis by non-EIA methods. Conclusions: The presence of circulating galactomannan is predictive of invasive aspergillosis in most pediatric oncology patients. Galactomannan antigenemia may precede clinical, microbiologic, or radiographic evidence of invasive aspergillosis.

Endemic fungal infections in solid organ and hematopoietic cell transplant recipients enrolled in the Transplant-Associated Infection Surveillance Network (TRANSNET)

Invasive fungal infections are a major cause of morbidity and mortality among solid organ transplant (SOT) and hematopoietic cell transplant (HCT) recipients, but few data have been reported on the epidemiology of endemic fungal infections in these populations.

Prevalence of Congenital Anomalies in Infants with in Utero Exposure to Antiretrovirals

Background: Although use of efficacious interventions, including antiretrovirals (ARVs), has dramatically reduced the rate of mother-to-child transmission of human immunodeficiency virus, the safety of in utero ARV exposure remains of concern. Methods: Data regarding 1112 infants enrolled in the International Maternal Pediatric Adolescent AIDS Clinical Trials Group protocol P1025 born between 2002 and 2007 were analyzed for this study. Congenital anomalies were classified based on the Metropolitan Atlanta Congenital Defects Program guidelines. Associations between congenital anomalies and timing of first in utero exposure to ARVs were evaluated by logistic regression analysis. Results: Congenital anomalies were identified and confirmed in 61 of the 1112 infants, resulting in a prevalence of 5.49/100 live births (95% confidence interval, 4.22–6.99). Among the 80 anomalies identified, the organ systems involved included cardiovascular (n = 33), musculoskeletal (n = 15), renal (n = 9), genitourinary (n = 6), craniofacial (n = 4), and central nervous system (n = 2). First trimester exposure to efavirenz was associated with a significantly increased risk of congenital anomalies (odds ratio, 2.84; 95% confidence interval, 1.13–7.16). No significant associations were observed between exposure to other individual ARVs or classes of ARVs started at any time during pregnancy and infant congenital anomalies. Conclusions: The observed rate of congenital anomalies in this cohort is higher than previously reported for the general population, but it is consistent with rates observed in other recent studies of children born to human immunodeficiency virus–infected women. Cardiovascular anomalies occurred most frequently. With the exception of a known teratogen (efavirenz), no statistically significant associations between in utero exposure to ARVs and congenital anomalies were identified.

Pneumococcal meningitis in children: relationship of antibiotic resistance to clinical characteristics and outcomes.

Background. The relationship of antibiotic susceptibility to clinical outcome in children with pneumococcal meningitis is uncertain. Previous studies have been limited by inclusion of relatively few patients infected with nonsusceptible pneumococci and inconsistent use of empiric vancomycin. Methods. Medical records of 86 children with culture-confirmed pneumococcal meningitis at a single institution from October, 1991, to October, 1999, were retrospectively reviewed, and differences in presentation and outcome based on antibiotic susceptibility of pneumococcal isolates were assessed. Results. Of 86 isolates 34 were nonsusceptible to penicillin (12 resistant). Of 60 isolates for which cefotaxime susceptibility data were available, 17 were nonsusceptible (12 resistant). Antibiotic susceptibility was not significantly associated with death, intensive care unit admission, mechanical ventilation, focal neurologic deficits, seizures, secondary fever, abnormal neuroimaging studies or hospital days. Children with penicillin-resistant isolates had significantly higher median blood leukocyte counts (24 100/&mgr;l vs. 15 700/&mgr;l, P = 0.03) and lower median CSF protein concentrations (85 mg/dl vs. 219 mg/dl, P = 0.04), were more likely to have a CSF glucose concentration of ≥50 mg/dl (7 of 11 vs. 15 of 68, P = 0.009) and had lower rates of sensorineural hearing loss (1 of 8 vs. 25 of 40, P = 0.02) than children with isolates that were not resistant to penicillin. Children with cefotaxime-nonsusceptible isolates had an increased median duration of primary fever compared with those with nonsusceptible strains (6 days vs. 3.5 days, P = 0.02). Conclusions. In children with pneumococcal meningitis, penicillin resistance was associated with a reduced risk of hearing loss, while cefotaxime resistance was associated with a longer duration of fever. Other outcome measures were not significantly influenced by the antibiotic susceptibility of pneumococcal isolates.