Recognition of Diagnostic Gaps for Laboratory Diagnosis of Fungal Diseases: Expert Opinion from the Fungal Diagnostics Laboratories Consortium (FDLC).

Fungal infections are a rising threat to our immunocompromised patient population, as well as other nonimmunocompromised patients with various medical conditions. However, little progress has been made in the past decade to improve fungal diagnostics. To jointly address this diagnostic challenge, the Fungal Diagnostics Laboratory Consortium (FDLC) was recently created. The FDLC consists of 26 laboratories from the United States and Canada that routinely provide fungal diagnostic services for patient care. A survey of fungal diagnostic capacity among the 26 members of the FDLC was recently completed, identifying the following diagnostic gaps: lack of molecular detection of mucormycosis; lack of an optimal diagnostic algorithm incorporating fungal biomarkers and molecular tools for early and accurate diagnosis of Pneumocystis pneumonia, aspergillosis, candidemia, and endemic mycoses; lack of a standardized molecular approach to identify fungal pathogens directly in formalin-fixed paraffin-embedded tissues; lack of robust databases to enhance mold identification with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry; suboptimal diagnostic approaches for mold blood cultures, tissue culture processing for Mucorales, and fungal respiratory cultures for cystic fibrosis patients; inadequate capacity for fungal point-of-care testing to detect and identify new, emerging or underrecognized, rare, or uncommon fungal pathogens; and performance of antifungal susceptibility testing. In this commentary, the FDLC delineates the most pressing unmet diagnostic needs and provides expert opinion on how to fulfill them. Most importantly, the FDLC provides a robust laboratory network to tackle these diagnostic gaps and ultimately to improve and enhance the clinical laboratory's capability to rapidly and accurately diagnose fungal infections.

Use of diagnostic stewardship practices to improve urine culturing among SHEA Research Network hospitals.

This survey investigated interventions used by acute-care hospitals to reduce the detection of asymptomatic bacteriuria. Half of the respondents reported using reflex urine cultures but with varied urinalysis criteria and perceived outcomes. Other diagnostic stewardship interventions for urine culture ordering and specimen quality were less common.

Poor yield of Clostridium difficile testing algorithms using glutamate dehydrogenase antigen and C. difficile toxin enzyme immunoassays in a pediatric population with declining prevalence of clostridium difficile strain BI/NAP1/027.

We compared the performance of algorithmic Clostridium difficile infection (CDI) diagnosis with four molecular tests in children. Stool samples in patients 1-18 years old were tested with an algorithm (C. Diff Quik Chek Complete (QCC) reflexed to illumigene C. difficile); AmpliVue C. difficile (ACD); Lyra Direct C. difficile (Lyra); BD MAX C diff (BDM); and Xpert C. difficile (XCD). The gold standard was positivity by two tests. Sensitivity, specificity, positive predictive value, and negative predictive value were 85%, 99%, 93%, 97% for the algorithm; 21%, 99%, 78%, 87% for QCC's toxin component; 94%, 99%, 94%, 99% for ACD; 88%, 99%, 94%, 98% for Lyra; 94%, 100%, 100%, 99% for BDM, and 94%, 99%, 94% and 99% for XCD. 9.6% of samples were ribotype 027. Algorithms may detect CDI with lower sensitivity compared to molecular methods in children. This may be related to low prevalence of NAP-1/ribotype 027.

The Association between Positive Tracheal Aspirate Cultures and Adverse Pulmonary Outcomes in Preterm Infants with Severe Bronchopulmonary Dysplasia.

Objective Bacterial colonization of the airway may contribute to the development of bronchopulmonary dysplasia. Whether airway colonization increases risk for later adverse respiratory outcomes is less clear. We described tracheal aspirate culture results obtained from preterm infants receiving mechanical ventilation at 36 weeks postmenstrual age (PMA) and evaluated the association between bacteria type and the risk for prolonged supplemental oxygen use. Study Design We conducted a retrospective, single-center cohort study comparing infants (1) with and without a tracheal aspirate culture that grew a Gram-negative rod (GNR) and (2) with and without a culture that grew a Gram-positive cocci (GPC). Results Among 121 infants, 65 (53.7%) and 51 (42.2%) had a tracheal aspirate culture that grew a potentially pathogenic GNR and GPC prior to 36 weeks PMA, respectively. GNR were associated with increased risk for death or use of supplemental oxygen at discharge (adjusted odds ratio [aOR], 6.2; 95% confidence interval [CI], 1.8-21.1), and use of supplemental oxygen at discharge among survivors (aOR, 5.5; 95% CI, 1.6-19.0). GPC did not affect the risk for any study outcomes. Conclusion GNR but not GPC in the airways of preterm infants receiving mechanical ventilation at 36 weeks PMA is associated with increased risk for prolonged supplemental oxygen use.

Positive Impact of Fungal Histopathology on Immunocompromised Pediatric Patients With Histology-Proven Invasive Fungal Infection.

OBJECTIVES: We investigated the performance and the clinical impact of histologic examination of infected tissue in patients with suspected invasive fungal infection (IFI) at a tertiary pediatric center. METHODS: Unique episodes of IFI were identified from January 1, 2001, through December 31, 2012. Surgical pathology reports, fungal culture results, and clinical data were abstracted from medical records. RESULTS: Forty-seven patients with IFI were identified. Each patient had one episode of IFI. Risk factors included chemotherapy for an oncologic condition (n = 35), hematopoietic stem cell transplantation (n = 6), solid organ transplantation (n = 4), and primary immunodeficiency (n = 2). Tissue was obtained from deep subcutaneous tissue (n = 21), visceral organs (14 lungs, five livers, and one spleen), or the sinonasal cavity (n = 6). Fungal culture was ordered in 40 of the 47 episodes of IFI. Fungus grew in 27 (68%) of the 40 cultures submitted, and all isolates were concordant with histology. Medical records were available for 36 (77%) of 47 patients. Communication of histology results prompted changes in antifungal therapy 64% of the time. This included initiation of antifungal therapy in 13 patients who were not previously receiving therapy. Fifteen (42%) patients underwent surgical excision within 48 hours of histologic diagnosis. CONCLUSIONS: Histology can provide rapid, accurate, and clinically actionable information to clinicians caring for children with IFI.