Detection of SARS-CoV-2 infection in asymptomatic populations using the DiaSorin molecular Simplexa and Roche Cobas EUA assays

Identification of asymptomatic patients is necessary to control the COVID-19 pandemic and testing is one of the measures to detect this population. We evaluated the clinical correlation of the DiaSorin Molecular Simplexa COVID-19 Direct (DiaSorin Molecular) and Roche Cobas 6800 SARS-CoV-2 (Roche) assays using 253 oropharyngeal (OP) swab specimens collected from asymptomatic patients. Agreement between DiaSorin Molecular and Roche was 97% (95% CI, 0.94 to 0.99), with a κ statistic of 0.90 (95% CI, 0.83 to 0.97) and a PPA of 89% (95% CI, 0.76 to 0.96) and NPA of 99% (95% CI, 0.97 to 0.99). Simple regression analysis of Ct values revealed a regression line of y = 1.065*X - 5.537 with a Pearson's r of 0.8542, indicating a good correlation between both platforms. The DiaSorin Molecular assay demonstrates clinical performance comparable to that of Roche in this population.

Osteomyelitis Due to Mycobacterium goodii in an Adolescent, United States

Osteomyelitis is a rare clinical manifestation of infection with nontuberculous mycobacteria (NTM). We report an adolescent with femoral osteomyelitis associated with prosthetic material due to an emerging pathogen, Mycobacterium goodii. Application of secA1 and 16S ribosomal RNA gene sequencing reliably determined the NTM species, enabling targeted antimicrobial therapy.

Clinical Evaluation and Utilization of Multiple Molecular In Vitro Diagnostic Assays for the Detection of SARS-CoV-2

Objectives

To evaluate the clinical performance of 3 molecular assays for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).

Methods

We used 184 nasopharyngeal swab specimens to compare Abbott ID NOW COVID-19 (Abbott ID NOW), DiaSorin Molecular Simplexa COVID-19 Direct (DiaSorin Simplexa), and Roche cobas 6800 SARS-CoV-2 (Roche cobas) assays. In a separate analysis, 3 specimens (nasopharyngeal, oropharyngeal, and nasal) were collected from 182 unique patients presenting to the emergency department with suspicion of coronavirus disease 2019 and were tested utilizing Abbott ID NOW. To further characterize each assay, relative limits of detection were evaluated utilizing positive nasopharyngeal patient samples.

Results

The positive percent agreement was 91% (95% confidence interval [CI], 0.76-0.97) for Abbott ID NOW and 100% (95% CI, 0.90-1.00) for DiaSorin Simplexa and Roche cobas. The negative percent agreement was 100% (95% CI, 0.98-1.00) for all 3 assays. All swab types tested with the Abbott assay produced concordant results. Polymerase chain reaction assays had approximately 10 to 100 times lower limits of detection than Abbott ID NOW.

Conclusions

Based on these evaluations, a multiplatform testing approach is proposed, depending on patient population and assay sensitivity, to address testing needs during a public health emergency.

Identification of Mycobacterium porcinum in patients with cystic Fibrosis: Pathogen or contaminant?

BACKGROUND

Mycobacterium porcinum is a non-tuberculous mycobacterium (NTM) identified in potable water. The identification and clinical impact of M. porcinum in patients with cystic fibrosis (CF) has not been described. In our institution, M. porcinum was isolated exclusively during hospitalization in a cluster of patients with CF.

METHODS

Patients with CF who were hospitalized between September 2016 and September 2018 and could expectorate sputum were included, and samples were processed per institutional guidelines. Post-hospitalization and one-year clinical outcomes on those who isolated M. porcinum in respiratory cultures were reviewed. Whole genome sequencing was performed on M. porcinum isolates obtained from patients and environmental sources to identify source of acquisition.

RESULTS

Review of 14 CF patients with 16 M. porcinum isolates revealed rapid time to culture positivity within 0.8 (0.04-8.0) days after admission. M. porcinum was isolated in teenagers and adults irrespective of baseline pulmonary function, body mass index, or CF genotype. Whole genome sequencing suggested all isolates belong to the same M. porcinum strain and confirmed the source of acquisition to the ice machine. Review of patients' clinical course, including three patients who underwent lung transplantation, suggested a pseudo-outbreak with minimal clinical impact.

CONCLUSIONS

NTM, including M. porcinum, are ubiquitous in potable water and institutional water reservoirs. Our findings suggest M. porcinum is a transient colonizer rather than a pathogen. Challenges exist in discerning the role of NTM as a contributor of pulmonary morbidity in patients with CF, and adherence to established guidelines regarding NTM related pulmonary disease remains important.

641. Evaluation of the FilmArray Pneumonia Panel and Potential Impact of Antimicrobial Use on Patients in a Trauma and Medical Intensive Care Unit

Background

Organisms causing infections of the lower respiratory tract in hospitalized patients can lead to high morbidity and mortality. Identification of the agents of pneumonia allows implementation of appropriate antimicrobial therapy and fast and accurate results are essential for the application of the correct antimicrobial regimen.

Methods

For 6 months results of quantitative bronchioalveolar lavage (Q-BALs) respiratory cultures, ordered as a standard of care for patients in our intensive care unit, were compared with the results obtained by a new multiplex molecular assay for the detection of lower respiratory tract pathogens, the FilmArray pneumonia panel (PP). The panel offers semi-quantitation of the bacterial targets that were compared with the quantitative results of the Q-BALs. Additionally, a retrospective chart review was performed to examine whether there would be any difference in the timing of appropriate antimicrobial therapy if the results of the panel were to be available for those patients. Appropriate antimicrobial therapy was determined according to the institution protocol for treatment of patients for ventilator-associated pneumonia based on the results of the quantitative cultures

Results

Thirty-six unique patients Q-BALs were run and of those there was 82% agreement on the detected targets between cultures and PP. Six targets were not detected by the panel (yeast, S. maltophilia, Streptococci, Salmonella spp.). M. catarrhalis, S. agalactiae and 3 viral targets were detected only by the panel. There was 100% agreement between the panel detected resistance markers and the culture isolates susceptibilities. Of the 36 patients, 12 were excluded because their medical records were not available for review. Of the 24 reviewed, 8 (33.3%) would have de-escalation in their antibiotics use at least 24h earlier due to the PP result. Eight (33.3%) would have no potential change in therapy and 8 (33.3%) could have inappropriate escalation or continuation due to reporting of potential pathogens by the PP but recorded as normal flora by cultures.

Conclusion

The use of PP would lead to a reduction of unnecessary antimicrobial therapy in 1/3 of the patients examined. However, quantification of organisms otherwise reported as normal flora may lead to unnecessary treatment and requires education of staff to understand the results of the assay.

Disclosures

All authors: No reported disclosures.

2314. Invasive Haemophilus influenzae Infections in Children: A 10-Year Study

Background

The rate of Haemophilus influenzae type b (HIB) infections has decreased dramatically since the use of HIB vaccines in infants and children. The current prevalence of invasive HIB infections and those due to non-type b H. influenzae is not fully known. The objective was to describe the cases of all invasive H. influenzae infections and describe the spectrum and severity of clinical disease.

Methods

Retrospective study of all hospitalized patients with culture-proven invasive Haemophilus influenzae infections at Nationwide Children’s Hospital, Columbus, Ohio, from 2009 to 2018. The electronic health records were reviewed for pertinent demographic, clinical, laboratory data, and outcomes.

Results

There were a total of 59 culture-proven H. influenzae infections of which 12 were excluded due to insufficient patient data. The remaining 47 patients (32 [68%] male; 30 [64%] white, 8 [17%] African-American) and their culture results are provided in Table:

There were 14 (30%) patients with pneumonia and bacteremia, 6 (13%) with meningitis and bacteremia, 2 (4%) with only meningitis, 1 (2%) with bacteremia/meningitis and septic hip, 2 (4%) septic arthritis with bacteremia, 1 (2%) with periorbital cellulitis and bacteremia, and 21 (45%) with only bacteremia. Of the 3 cases of H. influenzae type b, 2 had not been vaccinated while 1 received only 1 dose of HIB vaccine.

Conclusion

Invasive H. influenzae infections were associated with substantial morbidity and a 2% case-fatality rate.

Disclosures

All authors: No reported disclosures.

Breakthrough Invasive Candidiasis in Children

Background

Breakthrough invasive candidiasis (bIC) has been described in adults, but the epidemiology and outcomes in children are unknown.

Methods

Retrospective cohort analysis of children diagnosed with IC from 9/1/09 to 1/30/17. bIC was defined as isolation of Candida spp. from sterile site despite receiving ≥3 doses of antifungal (AF) to which isolate is susceptible. Clinical and microbiological data, management, and outcomes were collected. Non-parametric and logistic regression statistics were applied.

Results

There were 92 patients with IC, 23 of which were bIC (Table 1). Underlying conditions included GI (n = 26), hem/onc (n = 17), prematurity (n = 16), cardiac (n = 15), HCT (n = 4), SOT (n = 5), and other (n = 9). Patients received an azole (n = 17), micafungin (n = 5), or amphotericin B (n = 1) for median of 20 days [3–522] before bIC as: prophylaxis (n = 8), targeted therapy (n = 5), or empiric fever driven therapy (n = 10). bIC was caused by non-albicans Candida in 16/23 (70%) cases. Compared with IC controls, children with bIC had increased ICU admission, vasopressor use, mechanical ventilation, and renal failure (all with P < 0.01). In multivariate analysis, immunosuppression was an independent risk factor for bIC (OR 39.4, 95% CI 7.5–205). Death attributable to IC occurred in bIC group (n = 3, P = 0.04).

Conclusion

bIC in our cohort was caused most frequently by non-albicans Candida spp. and associated with significantly worse outcomes, including mortality.

Disclosures

All authors: No reported disclosures.