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Alex Greninger

Publications and source records attributed to Alex Greninger.

2 recordsLinked to original sources

Rapid metagenomic next-generation sequencing during an investigation of hospital-acquired human parainfluenza virus 3 infections

Metagenomic next-generation sequencing (mNGS) is increasingly used for the unbiased detection of viruses, bacteria, fungi, and eukaryotic parasites in clinical samples. Whole genome sequencing (WGS) of clinical bacterial isolates has been shown to inform hospital infection prevention practices, but the use of this technology during potential respiratory virus outbreaks has not been taken advantage of. Here, we report on the use of mNGS to inform the real-time infection prevention response to a cluster of hospital-acquired human parainfluenza 3 virus (HPIV3) infections at a childrens hospital. Isolates from 3 patients with hospital-acquired HPIV3 identified over a 12-day period on a general medical unit and 10 temporally-associated isolates from patients with community-acquired of HPIV3 were analyzed. Our sample-to-sequencer time was <24 hours while our sample-to-answer turn-around time was <60 hours with a hands-on time of approximately 6 hours. Eight (2 case isolates and 6 control isolates) of 13 samples had sufficient sequencing coverage to yield whole genomes for HPIV3, while 10 (2 cases and 8 controls) of 13 samples gave partial genomes and all 13 samples had >1 read to HPIV3. Phylogenetic clustering revealed the presence of identical HPIV3 genomic sequence in the two of the cases with hospital-acquired infection, consistent with the concern for recent transmission within the medical unit. Adequate sequence coverage was not recovered for the third case. This work demonstrates the promise of mNGS to provide actionable information for infection control in addition to microbial detection.

Microbiology

Recent Outbreaks of Shigellosis in California Caused by Two Distinct Populations of Shigella sonnei With Increased Virulence or Fluoroquinolone Resistance

Shigella sonnei has caused unusually large outbreaks of shigellosis in California in 2014 - 2015. Preliminary data indicated the involvement of two distinct yet related bacterial populations, one from San Diego and San Joaquin (SD/SJ) and one from the San Francisco (SF) Bay area. Whole genome sequencing of sixty-eight outbreak and archival isolates of S. sonnei was performed to investigate the microbiological factors related to these outbreaks. Both SD/SJ and SF populations, as well as almost all of the archival S. sonnei isolates belonged to sequence type 152 (ST152). Genome-wide SNP analysis clustered the majority of California (CA) isolates to an earlier described global Lineage III, which has persisted in CA since 1986. Isolates in the SD/SJ population had a novel Shiga-toxin (STX)-encoding lambdoid bacteriophage, most closely related to that found in an Escherichia coli O104:H4 strain responsible for a large outbreak. However, the STX genes (stxla and stxlb) from this novel phage had sequences most similar to the phages from S. flexneri and S. dysenteriae. The isolates in the SF population yielded evidence of fluoroquinolone resistance acquired via the accumulation of point mutations in gyrA and parC genes. Thus, the CA S. sonnei lineage continues to evolve by the acquisition of increased virulence and antibiotic resistance, and enhanced monitoring is advocated for its early detection in future outbreaks.

Microbiology