scholarly journals The Stealthy Superbug: the Role of Asymptomatic Enteric Carriage in Maintaining a Long-Term Hospital Outbreak of ST228 Methicillin-Resistant Staphylococcus aureus

mBio ◽  
2016 ◽  
Vol 7 (1) ◽  
Author(s):  
Laurence Senn ◽  
Olivier Clerc ◽  
Giorgio Zanetti ◽  
Patrick Basset ◽  
Guy Prod’hom ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Whole Genome Sequencing ◽  
Genome Sequencing ◽  
Tertiary Care ◽  
Enteric Pathogens ◽  
Hospital Environment ◽  
Whole Genome ◽  
Care Hospital ◽  
Methicillin Resistant

ABSTRACT Whole-genome sequencing (WGS) of 228 isolates was used to elucidate the origin and dynamics of a long-term outbreak of methicillin-resistant Staphylococcus aureus (MRSA) sequence type 228 (ST228) SCC mec I that involved 1,600 patients in a tertiary care hospital between 2008 and 2012. Combining of the sequence data with detailed metadata on patient admission and movement confirmed that the outbreak was due to the transmission of a single clonal variant of ST228, rather than repeated introductions of this clone into the hospital. We note that this clone is significantly more frequently recovered from groin and rectal swabs than other clones ( P < 0.0001) and is also significantly more transmissible between roommates ( P < 0.01). Unrecognized MRSA carriers, together with movements of patients within the hospital, also seem to have played a major role. These atypical colonization and transmission dynamics can help explain how the outbreak was maintained over the long term. This “stealthy” asymptomatic colonization of the gut, combined with heightened transmissibility (potentially reflecting a role for environmental reservoirs), means the dynamics of this outbreak share some properties with enteric pathogens such as vancomycin-resistant enterococci or Clostridium difficile . IMPORTANCE Using whole-genome sequencing, we showed that a large and prolonged outbreak of methicillin-resistant Staphylococcus aureus was due to the clonal spread of a specific strain with genetic elements adapted to the hospital environment. Unrecognized MRSA carriers, the movement of patients within the hospital, and the low detection with clinical specimens were also factors that played a role in this occurrence. The atypical colonization of the gut means the dynamics of this outbreak may share some properties with enteric pathogens.

scholarly journals Enhanced Tracking of Nosocomial Transmission of Endemic Sequence Type 22 Methicillin-Resistant Staphylococcus aureus Type IV Isolates among Patients and Environmental Sites by Use of Whole-Genome Sequencing

2015 ◽  
Vol 54 (2) ◽  
pp. 445-448 ◽  
Author(s):  
Peter M. Kinnevey ◽  
Anna C. Shore ◽  
Micheál Mac Aogáin ◽  
Eilish Creamer ◽  
Gráinne I. Brennan ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Whole Genome Sequencing ◽  
Genome Sequencing ◽  
Sequence Type ◽  
Hospital Environment ◽  
Whole Genome ◽  
Single Nucleotide Variants ◽  
Methicillin Resistant ◽  
Content Type ◽  
Type Iv

Whole-genome sequencing (WGS) of 41 patient and environmental sequence type 22 methicillin-resistantStaphylococcus aureusstaphylococcal cassette chromosomemectype IV (ST22-MRSA-IV) isolates recovered over 6 weeks in one acute hospital ward in Dublin, Ireland, where ST22-MRSA IV is endemic, revealed 228 pairwise combinations differing by <40 single nucleotide variants corresponding to potential cross-transmission events (CTEs). In contrast, 15 pairwise combinations of isolates representing five CTEs were previously identified by conventional molecular epidemiological typing. WGS enhanced ST22-MRSA-IV tracking and highlighted potential transmission of MRSA via the hospital environment.

scholarly journals 531. Practical and Evidence-Based Considerations for Implementation of Bacterial Whole-Genome Sequencing Within Longitudinal Infection Control Practice

2019 ◽  
Vol 6 (Supplement_2) ◽  
pp. S255-S255
Author(s):  
Donald S Chen ◽  
Moira Quinn ◽  
Rita M Sussner ◽  
Guiqing Wang ◽  
John T Fallon ◽  
...  
Keyword(s):  
Infection Control ◽  
Whole Genome Sequencing ◽  
Genome Sequencing ◽  
Tertiary Care ◽  
False Negative ◽  
Lessons Learned ◽  
Evidence Based ◽  
Guidance Document ◽  
Whole Genome ◽  
Care Hospital

Abstract Background Whole-genome sequencing (WGS) of bacteria is becoming a routine tool within microbiology, yet its utility to help guide infection control (IC) practice longitudinally is underexplored. As with any technology adopted in the hospital, the integration of WGS into IC practice must be carefully managed and considered. We qualitatively report an evidence-based implementation workflow that considers WGS to help proactively guide IC professionals during investigation of infectious outbreaks. Methods We built upon lessons learned in an ongoing surveillance effort at a tertiary care hospital—utilizing retrospective WGS data within the Philips IntelliSpace Epidemiology system—to understand facilitators and barriers to the use of bacterial WGS longitudinally to inform IC workflow. Our team established a 9-month workgroup to study the practical aspects of implementing WGS in routine IC practice. From expert opinion collected via the workgroup, in addition to evidence from the literature, a workflow guidance document and checklist were codified. New ideas included incorporating education to promote the establishment of an IC triage process. Results Facilitators to implementation included ability to display genomic relatedness alongside relevant patient data to enable clinical actionability, ability to pivot time and resources rapidly when infections are a pseudo outbreak (false positive) or missed outbreak (false negative), opportunities for nuanced staff education, and willingness to be a first-of-kind adopter. Barriers were communication of genomic concepts to IC professionals and relevant institutional stakeholders, maintaining sharable notes of active investigations to promote data-sharing practices, and timing and review of relevant interventions into the facility workflow. Strategies to address these issues are considered. Conclusion This study provides a novel framework for adaptation of existing IC workflow strategies to leverage the utility of bacterial WGS, and it presents a schema to effectively engage relevant stakeholders, based on an analysis of the unique challenges inherent within IC practice. It also offers an innovative model for the development and implementation of IC workflows to account for, and adapt to, site-specific conditions. Disclosures All authors: No reported disclosures.

scholarly journals Unsuspected clonal spread of Methicillin-resistant Staphylococcus aureus causing bloodstream infections in hospitalized adults detected using whole genome sequencing

2021 ◽  
Author(s):  
Brooke Morgan Talbot ◽  
Natasia F Jacko ◽  
Robert A Petit ◽  
David A Pegues ◽  
Margot J Shumaker ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Whole Genome Sequencing ◽  
Genome Sequencing ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Bloodstream Infections ◽  
Whole Genome ◽  
Nucleotide Polymorphisms ◽  
Methicillin Resistant ◽  
Clonal Spread ◽  
Epidemiological Characteristics

Background: Though detection of transmission clusters of methicillin-resistant Staphylococcus aureus (MRSA) infections is a priority for infection control personnel in hospitals, the transmission dynamics of MRSA among hospitalized patients with bloodstream infections (BSIs) has not been thoroughly studied. Whole genome sequencing (WGS) of MRSA isolates for surveillance is valuable for detecting outbreaks in hospitals, but the bioinformatic approaches used are diverse and difficult to compare. Methods: We combined short-read WGS with genotypic, phenotypic, and epidemiological characteristics of 106 MRSA BSI isolates collected for routine microbiological diagnosis from inpatients in two hospitals over 12 months. Clinical data and hospitalization history were abstracted from electronic medical records. We compared three genome sequence alignment strategies to assess similarity in cluster ascertainment. We conducted logistic regression to measure the probability of predicting prior hospital overlap between clustered patient isolates by the genetic distance of their isolates. Results: While the three alignment approaches detected similar results, they showed some variation. A pangenome-based alignment method was most consistent across MRSA clonal complexes. We identified nine unique clusters of closely-related BSI isolates. Most BSI were healthcare-associated and community-onset. Our logistic model showed that with 13 single nucleotide polymorphisms the likelihood that any two patients in a cluster overlapped in a hospital was 50 percent. Conclusions: Multiple clusters of closely related MRSA isolates can be identified using WGS among strains cultured from BSI in two hospitals. Genomic clustering of these infections suggest that transmission resulted from a mix of community spread and healthcare exposures long before BSI diagnosis.

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