Diagnosis Of Invasive Infections Research Articles

#35: Rapid, Non-invasive Detection and Serial Monitoring of Invasive Fungal Infections in Immunocompromised Children Using the Karius Test (a Plasma-based Microbial Cell-free DNA Sequencing Test)

Abstract Background A diverse spectrum of invasive molds and fungi cause serious opportunistic infections in immunocompromised (IC) children. Their overlap in clinical presentation can make it challenging to differentiate among etiologies and optimally tailor antifungal therapy. Current methods to identify these pathogens lack sensitivity, are limited by long turnaround times and require an array of individual tests on invasively obtained specimens. The delay or lack of a pathogen diagnosis in combination with the reliance on invasive procedures leads to a dependence on broad empiric therapy, the development of antimicrobial resistance and increases in morbidity and mortality. Rapid, non-invasive diagnosis of invasive fungal infections through next-generation sequencing (NGS) of plasma microbial cell-free DNA (mcfDNA) offers a means to overcome these limitations. Methods Karius® Test (KT) results were reviewed for detections of Aspergillus, non-Aspergillus molds and Pneumocystis jirovecii (PJP) in children. KT, developed and validated in Karius’ CLIA certified/CAP accredited lab, detects microbial cell-free DNA (mcfDNA) can assist with the diagnosis of invasive infections. McfDNA is extracted, NGS is performed, human sequences removed and remaining sequences aligned to a curated pathogen database of >1400 organisms. Organisms present above a statistical threshold are reported and quantified. For > 85% of tests the time to result reporting is 24 hours from sample receipt. Clinical information was included from data submitted with the requisition or obtained at the time of reporting from clinical consultations with the provider. Results KT detected 7 different species of Aspergillus in 61 patients (74% IC, 40% with a pulmonary focus). KT detected 15 different non-Aspergillus molds in 51 patients (80% IC, 36% with a pulmonary focus). KT detected PJP in 37 patients (73% IC, 76% with a pulmonary focus, 54% with a DNA virus co-detection and 32% with a herpesvirus co-detections). There were 31 subjects with serial monitoring (97% IC, 70% with a pulmonary focus) including 48% with Aspergillus, 39% with non-Aspergillus molds and 12% with PJP (Figure 1). 71% of subjects demonstrated a decline in the quantitative mcfDNA signal over time; the duration of a positive mcfDNA signal ranged from 3–92 days (median 16 days, SD 22.4). Conclusions Plasma mcfDNA NGS offers a rapid, non-invasive means of detecting a broad diversity of invasive pathogens that overlap in their clinical presentations and are difficult to identify in immunocompromised children. The rapid turnaround time, non-invasive sampling and 1-sample-1000+test-solution may lead to a faster time to pathogen diagnosis, faster time to targeted therapy and obviate the need for invasive diagnostic procedures. The ability with a single test to concomitantly diagnose co-pathogens including reactivating herpesviruses that modulate the progression of principal infecting fungal pathogens (i.e. cytomegalovirus modulation of PJP) can help optimize care. Additionally, this convenient non-invasive means of serial testing of invasive fungal infections may serve as an indicator of burden of infection, provide insight into treatment efficacy and ultimately help define the length and mode (medical/surgical) of therapy required to improve outcomes. Additional studies correlating the mcfDNA signal with individual patient clinical and radiographic parameters will be important to further define the utility of serial mcfDNA monitoring.

Evaluation of Panfungal Marker (1,3)-⃞-D-Glucanin Diagnosis of Invasive Infections with Candida Species

Abstract Introduction. Although blood culture is considered a gold standard in diagnosis of invasive infections, it is still not reliable and fast enough for diagnosis of candidemia. Determination of serum (1,3)-⃞-D-glucan is a highly sensitive and specific test for invasive mycosis, and could probably be of benefit to patients with high risk for invasive infections with Candida species. Aim. The aim of this study was to prospectively evaluate the diagnostic performance of serum (1.3)-⃞-Dglucan BDG (Fungitell) assay, in comparison with blood culture, for diagnosis of invasive infections with Candida species. Methods. Blood and sera from 120 patients divided in 4 groups, hospitalized at the University clinics in Skopje, during a 2-year period, were investigated for invasive Candida infections. Blood was examined with conventional methods (automated BacT/Alert system, Gram stain and culture on fungal media). Identification of Candida species was performed with VITEK-2 system. Serum (1,3)-⃞-D-glucan was determined by means of Fungitell assay. Results. Positive blood culture was registered in 23.33%, 43.33%, 23.8% and in 3.33% of samples only in groups I, II, III and IV, respectively. Positive findings with (1,3)-⃞-D-glucan Fungitell assay at the same time with blood culture were detected in 83.33%, 76.67%, 30% and 26.67% in groups I, II, III and IV, respectively. The average concentration of BDG was highest in group I, followed by group II, group IV and group III. Conclusion. Our results suggest that a positive (1,3)-⃞-D-glucan assay could be a superior test in addition to the blood culture for diagnosis of candidemia and highlights the value of this test as a diagnostic adjunct in the serodiagnosis of an invasive candidiasis.

Invasive Infektion durch Streptococcus pneumoniae Serotyp 8 im Säuglingsalter

BackgroundDespite the (now) extended spectrum of pneumococcal vaccination by PCV13 (PCV: pneumococcal conjugate vaccine), invasive pneumococcal disease continues to occur.CaseWe report on a 4-month-old female infant who was admitted to the pediatric hospital because of high fever and decreased oral intake of 2 day’s duration prior to admission.DiagnosisAfter extensive diagnostics (blood work, catheter urinalysis, cerebrospinal fluid analysis and culture, blood culture, catheter urine culture, throat swab, stool test, sonography of the brain), a diagnosis of invasive infection by Streptococcus pneumoniae serotype 8 (meningitis, sepsis) was made. The hospital course was complicated by cerebral empyema.ConclusionConsideration should be given to adding more serotypes to the conjugate vaccine, especially those which are known for invasive infections, as in our case, serotype 8.

DIAGNOSIS VALUE OF BONE MARROW STUDY IN THE DISSEMINATED INFECTION BY MYCOBACTERIA: CASE REPORT

The bone marrow examination is useful in order to get an etiologic diagnosis of cytopenias and for the detection of opportunistic diseases in immunocompromised patients. Nevertheless, its role in the diagnosis of invasive infections caused by mycobacterium has not been clearly defined. We describe the case of a 42-year-old woman who was admitted to study anemia, diarrhea and constitutional syndrome during two months with medical history of human immunodeficiency virus-1 infection, old intravenous drug user, hepatitis C virus carrier, as well as having lymph node tuberculosis and tuberculous meningitis during six years. The hematologic assessment was requested for the peripheral blood examination, which showed severe hyporegenerative anemia, rouleaux, anisopoikilocytosis and neutrophilia. In the bone marrow biopsy imprint we observed a very hypoplastic eritroid series and many macrophages with spread granularity and cytoplasm, similar to the Gaucher’s cells, which presented erythrophagocytosis and birefringence enlarge forms scattered throughout the smear, suggesting mycobacteria, with these findings, we established the diagnostic suspicion of disseminated mycobacterial disease and started the empirical treatment for Mycobacterium avium intracellulare-tuberculosis on the same day of the procedure, the etiology infection was later confirm by cultures. In this case, the bone marrow examination allowed to establish an early diagnostic suspicion from the hematology laboratory and to start the treatment before the microbiologic result.

Usefulness of a rapid method to cultivate sterile body fluid specimens

At the present, diagnosis of invasive infections is commonly based on the cultivation of pathogenic microorganisms with subsequent morphological and biochemical identification, followed by several types of antimicrobial susceptibility tests. Early identification and rapid antimicrobial susceptibility testing of microorganisms causing these invasive and life-threatening infections are high priorities in clinical microbiology laboratories. Aim of our study was to investigate whether Uro4 HB&L automated system (Alifax S.p.A., Padova, Italy) anticipates the recovery of microorganisms from sterile body fluids other than traditional cultural methods.

Combined Positron Emission Tomography and Computerized Tomography (Pet Ct Scan) as An Aid in the Diagnosis of Invasive Infection in a Patient with Chronic Granulomatous Disease

Combined Positron Emission Tomography and Computerized Tomography (Pet Ct Scan) as An Aid in the Diagnosis of Invasive Infection in a Patient with Chronic Granulomatous Disease

Burn Wound Biopsy Multiple Uses in Patient Management

It is often exceedingly difficult to initially evaluate the depth of a burn wound and thus inaugurate appropriate definitive therapy. The clinical picture of the burn would may not always correlate with the true histologic depth of the injury. For this reason we have undertaken a program of obtaining punch biopsies of burn wounds in patients where the depth of the burn wound is equivocal. In such cases the biopsy has proven to be useful in guiding subsequent therapy. In addition to establishing the anatomic depth of injury, there are several other valuable uses of burn wound biopsies. The other uses are: diagnosis of invasive infection, quantitative bacterial culture, medical-legal values, psychological values and forensic utility.