A comprehensive evaluation of every patient with a bloodstream infection includes an attempt to identify the infectious source. Pathogens can originate from various places, such as the gut microbiome, skin, and external environment. Identifying the definitive origin of an infection would enable precise interventions focused on management of the source
1
,
2
. Unfortunately, hospital infection control practices are often informed by assumptions about the source of various specific pathogens; if these assumptions are incorrect they lead to interventions that do not decrease pathogen exposure
3
. Here, we develop and apply a streamlined bioinformatic tool, named StrainSifter, to match bloodstream pathogens precisely to a candidate source. We then leverage this approach to interrogate the gut microbiome as a potential reservoir of bloodstream pathogens in a cohort of hematopoietic cell transplantation recipients. We find that patients with
Escherichia coli
and
Klebsiella pneumoniae
bloodstream infections have concomitant gut colonization with these organisms, suggesting that the gut may be a source of these infections. We also find cases where classically non-enteric pathogens, such as
Pseudomonas aeruginosa
and
Staphylococcus epidermidis
, are found in the gut microbiome, thereby challenging existing informal dogma of these infections originating from environmental or skin sources. Thus, we present an approach to distinguish the source of various bloodstream infections, which may facilitate more accurate tracking and prevention of hospital-acquired infections.
In 2016, the US Food and Drug Administration banned the use of specific microbicides in some household and personal wash products due to concerns that these chemicals might induce antibiotic resistance or disrupt human microbial communities. Triclosan and triclocarban (referred to as TCs) are the most common antimicrobials in household and personal care products, but the extent to which TC exposure perturbs microbial communities in humans, particularly during infant development, was unknown. We conducted a randomized intervention of TC‐containing household and personal care products during the first year following birth to characterize whether TC exposure from wash products perturbs microbial communities in mothers and their infants. Longitudinal survey of the gut microbiota using 16S ribosomal RNA amplicon sequencing showed that TC exposure from wash products did not induce global reconstruction or loss of microbial diversity of either infant or maternal gut microbiotas. Broadly antibiotic‐resistant species from the phylum Proteobacteria, however, were enriched in stool samples from mothers in TC households after the introduction of triclosan‐containing toothpaste. When compared by urinary triclosan level, agnostic to treatment arm, infants with higher triclosan levels also showed an enrichment of Proteobacteria species. Despite the minimal effects of TC exposure from wash products on the gut microbial community of infants and adults, detected taxonomic differences highlight the need for consumer safety testing of antimicrobial self‐care products on the human microbiome and on antibiotic resistance.
Immunocompromised individuals are at high risk of developing Clostridium difficile-associated disease (CDAD). Fecal microbiota transplantation (FMT) is a highly effective therapy for refractory or recurrent CDAD and, despite safety concerns, has recently been offered to immunocompromised patients. We investigated the genomics of bacterial composition following FMT in immunocompromised patients over a 1-year period. Metagenomic, strain and gene-level bacterial dynamics were characterized in two CDAD-affected hematopoietic stem cell (HCT) recipients following FMT. We found alterations in gene content, including loss of virulence and antibiotic resistance genes. These alterations were accompanied by long-term bacterial divergence at the species and strain levels. Our findings suggest limited durability of the specific bacterial consortium introduced with FMT and indicate that alterations of the functional potential of the microbiome are more complex than can be inferred by taxonomic information alone. Our observation that FMT alone cannot induce long-term donor-like alterations of the microbiota of HCT recipients suggests that FMT cannot indefinitely supersede environmental and/or host factors in shaping bacterial composition.
The presented clinical practice guidelines of the Gastroenterological Scientific Society of Russia (GSSR), diagnostic, and therapeutic approaches for patients with digestive diseases during the COVID-19 pandemic. The guidelines were approved by the XXIII Congress of the GSSR and the 22nd International Slavonic-Baltic Scientific Forum “St. Petersburg — Gastro-2020 ON-LINE” (St. Petersburg, June 11, 2020).
Background: Populations of closely related microbial strains can be simultaneously present in bacterial communities such as the human gut microbiome. We recently developed a de novo genome assembly approach that uses read cloud sequencing to provide more complete microbial genome drafts, enabling precise differentiation and tracking of strain-level dynamics across metagenomic samples. In this case study, we present a proof-of-concept using read cloud sequencing to describe bacterial strain diversity in the gut microbiome of one hematopoietic cell transplantation patient over a 2-month time course and highlight temporal strain variation of gut microbes during therapy. The treatment was accompanied by diet changes and administration of multiple immunosuppressants and antimicrobials. Methods: We conducted short-read and read cloud metagenomic sequencing of DNA extracted from four longitudinal stool samples collected during the course of treatment of one hematopoietic cell transplantation (HCT) patient. After applying read cloud metagenomic assembly to discover strain-level sequence variants in these complex microbiome samples, we performed metatranscriptomic analysis to investigate differential expression of antibiotic resistance genes. Finally, we validated predictions from the genomic and metatranscriptomic findings through in vitro antibiotic susceptibility testing and whole genome sequencing of isolates derived from the patient stool samples. Results: During the 56-day longitudinal time course that was studied, the patient's microbiome was profoundly disrupted and eventually dominated by Bacteroides caccae. Comparative analysis of B. caccae genomes obtained using read cloud sequencing together with metagenomic RNA sequencing allowed us to identify differences in substrain populations over time. Based on this, we predicted that particular mobile element integrations likely resulted in increased antibiotic resistance, which we further supported using in vitro antibiotic susceptibility testing.
The paper presents the All-Russian consensus on the diagnosis and treatment of celiac disease in children and adults, which has been elaborated by leading experts, such as gastroenterologists and pediatricians of Russia on the basis of the existing Russian and international guidelines. The consensus approved at the 42nd Annual Scientific Session of the Central Research Institute of Gastroenterology on Principles of Evidence-Based Medicine into Clinical Practice (March 2-3, 2016). The consensus is intended for practitioners engaged in the management and treatment of patients with celiac disease. Evidence for the main provisions of the consensus was sought in electronic databases. In making recommendations, the main source was the publications included in the Cochrane Library, EMBASE, MEDLINE, and PubMed. The search depth was 10 years. Recommendations in the preliminary version were reviewed by independent experts. Voting was done by the Delphic polling system.
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