Grys, Thomas E

Abstract Background While most pulmonary infections with Coccidioides spp. are self-limited, a subset of patients is at higher risk for severe disease and extrapulmonary dissemination, including individuals with certain ethnic backgrounds. Disseminated disease can involve soft tissues, bones, and the central nervous system with high morbidity and mortality in the absence of antifungal treatment. Diagnosis of coccidioidomycosis can be challenged by the availability of specimens for culture or histopathology, confusion with, or lack of availability of various antibody tests and overall lack of consideration of Coccidioides spp. as the etiology of disease, especially in immunocompetent hosts. Methods We set out to characterize cases of disseminated coccidioidomycosis at our institution over a 7-year period, solely in immunocompetent hosts, to highlight diagnostic delays and determine which, if any, primary screening test might be the most useful. Results A total of 40 cases met our inclusion criteria, and 100% of these cases had positive immunoglobulin G antibodies on a US FDA-cleared Coccidioides spp. enzyme immunoassay. Nearly all of the cases (87%) had a delay in diagnosis and associated worsening of disease (71%). Locations of initial presentations that led to delayed recognition included primary care settings (56%), emergency departments (33%), and urgent care centers (11%), all in the region of Coccidioides spp. endemicity. Conclusions These findings highlight the need for interventions to increase awareness of the risk factors for, the symptoms of, and the appropriate testing options to diagnose disseminated coccidioidomycosis.

Abstract Early diagnosis and treatment are essential for improving outcomes of coccidioidal meningitis. While the detection of IgG by serologic testing of the cerebrospinal fluid (CSF) has been a mainstay of diagnosis for years, the diagnosis of coccidioidal meningitis in clinical practice can be very challenging due to suboptimal sensitivity of laboratory tests. We reviewed the results of the CSF diagnostic test results from the initial lumbar puncture in 110 patients with proven, probable, and likely coccidioidal meningitis from 1989 to 2024. One hundred four patients were diagnosed with coccidioidal meningitis on the initial CSF examination. The positivity rate of the first CSF testing was 89.1% (n = 64) for IgG by enzyme immunoassay, 62.2% (n = 98) for IgG by immunodiffusion, and 70.2% (n = 104) for IgG by complement fixation, 4.4% (n = 90) for fungal culture, 18.8% (n = 69) for polymerase chain reaction, and 33% (n = 21) for Coccidioides antigen. The non-specific fungal marker 1,3-β-d-glucan was positive in the CSF in 70.4% (n = 27) of samples. Contrasted brain magnetic resonance imaging identified leptomeningeal enhancement in 53.1%. Optimal detection of coccidioidal meningitis requires a combination of diagnostic modalities.

SUMMARY Antibody and antigen detection assays continue to play a significant role in the diagnosis of dimorphic fungal pathogens, including Blastomyces dermatitidis complex, Coccidioides immitis/posadasii , Paracoccidioides species, Histoplasma species , Sporothrix species, and Talaromyces marneffei . The performance characteristics of serologic and antigen detection assays for these pathogens are variable, however, influenced by multiple factors, including sample type, disease presentation, patient immunostatus, and timing of specimen collection relative to symptom onset. As a result, there is a need for a centralized document summarizing the accuracy of currently available antibody and antigen detection assays for each of these agents, including discussion of individual assay nuances and caveats that should be considered by clinicians and laboratorians alike. In addition, this review provides expert recommendations for the utilization and interpretation of serologic and antigen detection assays for these dimorphic pathogens.

Abstract Background Lymphocytic choriomeningitis virus (LCMV) infection in immunocompromised hosts can result in disseminated disease, meningoencephalitis, and death. Published cases in transplant recipients have been traced to transmission from infected donors. We report 2 cases of serious, non–donor-derived LCMV infection in solid organ transplant recipients. Methods Initial identification of LCMV infection was done by using metagenomic next-generation sequencing (mNGS). Subsequent evaluations and confirmatory testing involved molecular diagnostics, serology, and phylogenetic analysis. A detailed epidemiologic investigation was conducted. Results LCMV was detected by mNGS in 2 solid organ transplant recipients from distinct donors. A heart transplant recipient (from donor 1) died of progressive, disseminated LCMV infection, while a kidney transplant recipient (from donor 2) with LCMV meningoencephalitis survived. A multistate laboratory and epidemiologic investigation of both donors and all their organ recipients was initiated. Postmortem samples were obtained from both donors, and pretransplant and/or posttransplant samples were obtained from 5 of the 6 organ recipients. mNGS, serologic, and real-time reverse-transcription polymerase chain reaction testing confirmed LCMV infection in both solid organ transplant recipients. Epidemiologic investigation revealed significant pretransplant rodent exposures for both LCMV-infected recipients. Laboratory studies for the other organ recipients from both donors were negative for LCMV infection. Conclusions Our investigations suggest that LCMV infection in 2 solid organ transplant recipients originated from rodent exposure preceding transplantation and were not donor derived. Although uncommon, healthcare providers should be aware of LCMV-associated serious and life-threatening illness in immunocompromised hosts. Diagnostic modalities are limited to reference laboratories.

Abstract Metagenomic sequencing of plasma has been advertised by Karius, Inc. as a way to diagnose a variety of infectious syndromes. Due to the lack of robust evidence of clinical utility, our laboratory began actively stewarding Karius testing. Microbiology Directors recommended cancelation of Karius orders when certain criteria were identified. We set out to review Karius test requests in a 52-month period of stewardship, during which we recommended cancellation on 21 of 57 orders (37%). Of Karius tests sent on samples with negative conventional testing, only 3 (7%) had positive results for Karius with plausible explanatory etiologies. Of these three cases, two were empirically covered for the positive finding without improvement and one case was never treated. Twelve (29%) had positive results that were noted by infectious diseases (ID) to reflect insignificant detections. Given the 4-fold higher detection of insignificant Karius results, we set out to systematically analyze the literature for the experience of insignificant detections at other centers. When we compared studies that included healthy controls or had clinical adjudication of positive Karius findings by ID physicians, we found a median of 17.5% of individual patients that had positive insignificant detections of potential pathogenic bacteria or fungi. The most frequently detected species were as likely to be clinically adjudicated to be insignificant as they were to be significant within the same studies. Overall, these findings highlight limited utility of Karius testing and a need for careful stewardship, not only to ensure it is sent on patients who may benefit, but also to ensure results of potential pathogens are interpreted cautiously.

ABSTRACTCoccidioidesspp. are dimorphic fungi that are capable of infecting human and non-human mammals and can cause diverse manifestations of coccidioidomycosis or Valley fever (VF). In combination with clinical symptoms and radiographic findings, antibody-based diagnostic tests are often used to diagnose and monitor patients with VF. Chitinase 1 (CTS1) has previously been identified as the seroreactive antigen used in these diagnostic assays to detect anticoccidial IgG. Here, an indirect enzyme-linked immunosorbent assay to detect IgG to CTS1 demonstrated 165 of 178 (92.7%) patients with a positive result by immunodiffusion (ID) and/or complement fixation (CF) had antibodies to the single antigen CTS1. We then developed a rapid antibody lateral flow assay (LFA) to detect anti-CTS1 antibodies. Out of 143 samples tested, the LFA showed 92.9% positive percent agreement [95% confidence interval (CI), 84.3%–96.9%] and 97.7% negative percent agreement (95% CI, 87.9%–99.6%) with ID and CF assays. Serum or plasma from canines, macaques, and dolphins was also tested by the CTS1 LFA. Test line densities of the CTS1 LFA correlated in a linear manner with the reported CF and ID titers for human and non-human samples, respectively. This 10-min point-of-care test for the rapid detection of anti-coccidioidal antibodies could help to inform healthcare providers in real-time, potentially improving the efficiency of healthcare delivery.

In southwestern and western regions of the United States, at least half a million diagnostic tests for coccidioidomycosis (valley fever) are run annually. Enzyme immunoassays (EIAs) are blood tests which require precise dilution of patient serum prior to testing.