Seafood-Associated Outbreak of ctx-Negative Vibrio mimicus Causing Cholera-Like Illness, Florida, USA

Vibrio mimicus caused a seafood-associated outbreak in Florida, USA, in which 4 of 6 case-patients were hospitalized; 1 required intensive care for severe diarrhea. Strains were ctx-negative but carried genes for other virulence determinants (hemolysin, proteases, and types I-IV and VI secretion systems). Cholera toxin-negative bacterial strains can cause cholera-like disease.

322. Clinical-Grade Metagenomics in Urinary Tract Infections: Improving Performance of Next-Generation Sequencing Assays Using Internal Controls and Machine Learning

Background

Shotgun sequencing-based metagenomics is a useful approach to profiling microbiomes in environmental and patient samples. In a clinical setting, metagenomic techniques have the advantage of identifying organisms, which cannot be readily cultured or confirmed by other techniques. We have developed a clinical-grade, streamlined metagenomics-based pipeline that includes regulatory compliant method considerations, such as an internal control followed by a machine-based learning (ML) process to identify pathogens in urine samples.

Methods

We built an optimized novel end-to-end NGS assay pipeline that harnesses pathogen-specific genome data to detect bacterial species. We processed de-identified clinical urine specimens, collected from patients symptomatic for urinary tract infection (UTI). This workflow includes an IPC, QIACube-MDx extraction, library preparation and Illumina NextSeq 550 sequencing and a novel interpretable ML based analytic approach, Biotia-DX. Clinical culture results and qPCR were used as a baseline for the assay to train the ML model and to establish accuracy relative to the clinical standard of care.

Results

We clinically validated over 40 key uropathogens and conducted clinical studies of specificity, intra/inter reproducibility, accuracy in urine specimens (n=300), and limit of detection in E. coli, K. pneumoniae, P. mirabilis, S. aureus, E. faecalis and Candida. Additionally, the implementation of an internal control coupled with our Biotia-DX software provides an accurate (F1 score 94.3%) and highly sensitive clinical grade diagnostic tool.

Conclusion

Urine has historically presented a challenge for diagnostics via culturing, with a high rate of culture-negative results (∼30% on average). We improved the clinical utility of an NGS urine assay by leveraging an IPC and ML software. This decreased the rate of false positive species called in a sample relative to other NGS techniques and allows for greater sensitivity and taxonomic specificity. This assay may be especially useful for low colony-count or negative-culture samples to diagnose and guide patient treatment.

Disclosures

Mara Couto-Rodriguez, MS, Biotia Inc.: Employee of Biotia Inc. a for-profit biotechnology company David C. Danko, PhD, Biotia Inc.: Employee of Biotia Inc. a for-profit biotechnology company Xavier O. Jirau Serrano, MS, Biotia Inc.: Employee of Biotia Inc. a for-profit biotechnology company Taylor Paisie, MS, Biotia Inc.: Employee of Biotia Inc. a for-profit biotechnology company John C. Papciak, BS, Biotia Inc.: Employee of Biotia Inc. a for-profit biotechnology company Eszter Szollosi, BS, Biotia Inc.: Employee of Biotia Inc. a for-profit biotechnology company Christopher E. Mason, PhD, Biotia Inc.: Advisor/Consultant|Biotia Inc.: Board Member|Biotia Inc.: Ownership Interest Caitlin Otto, PhD, D(ABMM), Biotia Inc.: Advisor/Consultant Niamh B. O'Hara, PhD, Biotia Inc.: Board Member|Biotia Inc.: Ownership Interest Dorottya Nagy-Szakal, MD PhD, Biotia Inc.: Employee of Biotia Inc. a for-profit biotechnology company|Biotia Inc.: Stocks/Bonds.

Analysis of the Origin and Dissemination of HIV-1 Subtype C in Bulgaria

HIV-1 subtype C is the most abundant strain of HIV-1 infections worldwide and was found in the first known patients diagnosed with HIV/AIDS in Bulgaria in 1986. However, there is limited information on the molecular-epidemiological characteristics of this strain in the epidemic of the country. In this study, we analyze the evolutionary history of the introduction and dissemination of HIV-1 subtype C in Bulgaria using global phylogenetic analysis, Bayesian coalescent-based approach, and molecular clock methods. All available samples with HIV-1 subtype C from individuals diagnosed with HIV/AIDS between 1986 and 2017 were analyzed. Men and women were equally represented, and 24.3% of patients reported being infected abroad. The global phylogenetic analysis indicated multiple introductions of HIV-1 subtype C from various countries of the world. The reconstruction of a Bayesian time-scaled phylogenies showed that several Bulgarian strains segregated together in clusters, while others were intermixed in larger clades containing strains isolated from both European and non-European countries. The time-scale of HIV-1 subtype C introductions in Bulgaria demonstrates the early introduction of these viruses in the country. Our in-depth phylogenetic and phylogeographic analyses are compatible with a scenario of multiple early introductions in the country followed by limited local distribution in the subsequent years. HIV-1 subtype C was introduced in the early years of the epidemic, originating from different countries of the world. Due to the comprehensive measures for prevention and control in the early years of the epidemic in Bulgaria, HIV-1 subtype C was not widely disseminated among the general population of the country.

Detection and phylogenetic characterization of arbovirus dual-infections among persons during a chikungunya fever outbreak, Haiti 2014

In the context of recent arbovirus epidemics, questions about the frequency of simultaneous infection of patients with different arbovirus species have been raised. In 2014, a major Chikungunya virus (CHIKV) epidemic impacted the Caribbean and South America. As part of ongoing screening of schoolchildren presenting with acute undifferentiated febrile illness in rural Haiti, we used RT-PCR to identify CHIKV infections in 82 of 100 children with this diagnosis during May-August 2014. Among these, eight were infected with a second arbovirus: six with Zika virus (ZIKV), one with Dengue virus serotype 2, and one with Mayaro virus (MAYV). These dual infections were only detected following culture of the specimen, suggesting low viral loads of the co-infecting species. Phylogenetic analyses indicated that the ZIKV and MAYV strains differ from those detected later in 2014 and 2015, respectively. Moreover, CHIKV and ZIKV strains from co-infected patients clustered monophyletically in their respective phylogeny, and clock calibration traced back the common ancestor of each clade to an overlapping timeframe of introduction of these arboviruses onto the island.

Evidence for Mother-to-Child Transmission of Zika Virus Through Breast Milk

Zikavirus (ZIKV) is an emerging viral pathogen that continues to spread throughout different regions of the world. Herein we report a case that provides further evidence that ZIKV transmission can occur through breastfeeding by providing a detailed clinical, genomic, and virological case-based description.

Detection of Alphacoronavirus vRNA in the Feces of Brazilian Free-Tailed Bats (Tadarida brasiliensis) from a Colony in Florida, USA

Bats are natural reservoirs of coronaviruses and other viruses with zoonotic potential. Florida has indigenous non-migratory populations of Brazilian free-tailed bats (Tadarida brasiliensis) that mostly roost in colonies in artificial structures. Unlike their counterparts in Brazil and Mexico, the viruses harbored by the Florida bats have been underexplored. We report the detection of an alphacoronavirus RNA-dependent RNA polymerase (RdRp) gene sequence in the feces of two of 19 different T. brasiliensis that were capture/release bats that had been evaluated for overall health. The RdRp sequence is similar but not identical to previously detected sequences in the feces of two different species of bats (T. brasiliensis and Molossus molossus) in Brazil. In common with the experience of others doing similar work, attempts to isolate the virus in cell cultures were unsuccessful. We surmise that this and highly related alphacoronavirus are carried by Brazilian free-tailed bats living in a wide eco-spatial region. As various coronaviruses (CoVs) that affect humans emerged from bats, our study raises the question whether CoVs such as the one detected in our work are yet-to-be-detected pathogens of humans and animals other than bats.

Zika and Chikungunya virus co-infection in a traveller returning from Colombia, 2016: virus isolation and genetic analysis

Introduction:

Zikavirus (ZIKV) and Chikungunyavirus (CHIKV) can share the same mosquito vector, and co-infections by these viruses can occur in humans. While infections with these viruses share commonalities, CHIKV is unique in causing arthritis and arthralgias that may persist for a year or more. These infections are commonly diagnosed by RT–PCR-based methods during the acute phase of infection. Even with the high specificity and sensitivity characteristic of PCR, false negatives can occur, highlighting the need for additional diagnostic methods for confirmation.

Case presentation:

On her return to the USA, a traveller to Colombia, South America developed an illness consistent with Zika, Chikungunya and/or Dengue. RT-PCR of her samples was positive only for ZIKV. However, arthralgias persisted for months, raising concerns about co-infection with CHIKV or Mayaro viruses. Cell cultures inoculated with her original clinical samples demonstrated two types of cytopathic effects, and both ZIKV and CHIKV were identified in the supernatants. On phylogenetic analyses, both viruses were found to be related to strains found in Colombia.

Conclusion:

These findings highlight the need to consider CHIKV co-infection in patients with prolonged rheumatological symptoms after diagnosis with ZIKV, and the usefulness of cell culture as an amplification step for low-viremia blood and other samples.