Prospectus, April 10, 2002

https://spark.parkland.edu/prospectus_2002/1012/thumbnail.jp

Defining nosocomial transmission of Escherichia coli and antimicrobial resistance genes: a genomic surveillance study

E. coli is a leading cause of bloodstream infections. Developing interventions to reduce this burden requires an understanding of the frequency of nosocomial transmission, but available evidence is limited. This study aimed to detect and characterise transmission of E. coli and associated plasmids in a hospitalised cohort. Methods: Genomic surveillance of E. coli was conducted in a prospective observational cohort study of hospitalised adult patients over 6 months in Cambridge, England. Stool samples were collected from study participants on admission, weekly and discharge. We sequenced multiple E. coli colonies (median=5) from each stool. A genetic threshold to infer E. coli transmission was defined by maximum within-host SNP diversity and the probability of drawing observed pairs of between-patient isolates at different SNP thresholds. Findings: We obtained and cultured 376 stools from 149 patients, of which 152 stools from 97 patients grew E. coli. We identified extensive diversity in the bacterial population (90 sequence types, STs), and mixed E. coli ST carriage in almost half of patients (26%, 13% and 6% patients carried 2, 3 or >4 STs, respectively). Using a 17 SNP cut-off we identified 10 clusters (defined as >2 cases) involving 20 patients. The largest cluster contained 7 patients, while 4 patients were linked to multiple clusters. Half of cases in the 10 clusters also had a strong epidemiological link to another patient in the cluster. A minority of all patients (17/149, 11%) carried extended-spectrum beta-lactamase (ESBL)-producing E.coli, the most common of which was blaCTX-M-15 (12/17, 71%). Long-read sequencing revealed that blaCTX-M- 40 was often integrated into the chromosome, with little evidence for plasmid-mediated transmission. Seven patients developed E. coli bloodstream infection, four with identical strains in those in stool; two of these had documented nosocomial acquisition. Interpretation: We provide evidence of bacterial transmission and endogenous infections during routine care by integrating genomic and epidemiological data and through determination of a genetic similarity cut-off informed by within-host diversity in the population studied. Our findings challenge single colony-based investigations, and the paradigm of plasmid spread in this setting

Prospectus, September 5, 2001

https://spark.parkland.edu/prospectus_2001/1021/thumbnail.jp

A One Health study of the genetic relatedness of Klebsiella pneumoniae and their mobile elements in the East of England

Klebsiella pneumoniae is a human, animal and environmental commensal and a leading cause of nosocomial infections, which are often caused by multi-resistant strains that are challenging to treat. We conducted a One Health evaluation of putative sources of K. pneumoniae that are carried by, and infect hospital patients. This combined data from a six-month study on two haematology wards at Addenbrooke’s Hospital, Cambridge, in 2015 to isolate K. pneumoniae from stool, blood and the environment, and a cross-sectional survey of K. pneumoniae from 29 livestock farms, 97 meat products, the hospital sewer and 20 municipal wastewater treatment plants in the East of England between 2014 and 2015. K. pneumoniae was isolated from stools of 17/149 (11%) patients and 18/922 swabs of their environment, together with one patient bloodstream infection during the study and 4 others over a 24-month period. Each patient carried one or more lineages that was unique to them, but two broad environmental contamination events and patient-environmental transmission were identified. K. pneumoniae was isolated from cattle and poultry, hospital sewage and 12/20 wastewater plants. There was low genetic relatedness between isolates from patients/their hospital environment versus isolates from elsewhere. Identical genes encoding cephalosporin resistance were carried by isolates from different reservoirs, but were carried on different plasmids by isolates from patients/their environment versus elsewhere. We identified no patient-to-patient transmission and no evidence for livestock as a source of K. pneumoniae infecting humans, but our findings reaffirm the importance of the hospital environment as a source of K. pneumoniae associated with serious human infection.This work was supported by the Health Innovation Challenge Fund (WT098600, HICF-T5-342), a parallel funding partnership between the Department of Health and Wellcome Trust. The views expressed in this publication are those of the author(s) and not necessarily those of the Department of Health or Wellcome Trust. This project was also funded by a grant awarded to the Wellcome Trust Sanger Institute (098051). TG is a Wellcome Trust Research Training Fellow (103387/Z/13/Z). CL is a Wellcome Trust Sir Henry Postdoctoral Fellow (110243/Z/15/Z). DJ is funded by the Wellcome Trust grant 098051

Prospectus, April 17, 2002

https://spark.parkland.edu/prospectus_2002/1013/thumbnail.jp

Detection of vancomycin-resistant Enterococcus faecium hospital-adapted lineages in municipal wastewater treatment plants indicates widespread distribution and release into the environment

Vancomycin-resistant Enterococcus faecium (VREfm) is a leading cause of healthcare-associated infection. Reservoirs of VREfm are largely assumed to be nosocomial although there is a paucity of data on alternative sources. Here, we describe an integrated epidemiological and genomic analysis of E. faecium associated with bloodstream infection and isolated from wastewater. Treated and untreated wastewater from 20 municipal treatment plants in the East of England, United Kingdom was obtained and cultured to isolate E. faecium, ampicillin-resistant E. faecium (AREfm) and VREfm. VREfm was isolated from all 20 treatment plants and was released into the environment by 17/20 plants, the exceptions using terminal ultraviolet light disinfection. Median log10 counts of AREfm and VREfm in untreated wastewater from ten plants in direct receipt of hospital sewage was significantly higher than ten plants that were not. We sequenced and compared the genomes of 423 isolates from wastewater with 187 isolates associated with bloodstream infection at five hospitals in the East of England. Amongst 481 E. faecium isolates belonging to the hospital-adapted clade, we observed genetic intermixing between wastewater and bloodstream infection, with highly related isolates shared between a major teaching hospital in the East of England and 9/20 plants. We detected 28 antibiotic resistance genes in the hospital-adapted clade, of which 23 were represented in bloodstream, hospital sewage and municipal wastewater isolates. We conclude that our findings are consistent with widespread distribution of hospital-adapted VREfm beyond acute healthcare settings with extensive release of VREfm into the environment in the East of England.This publication presents independent research supported by the Health Innovation Challenge Fund (WT098600, HICF-T5-342), a parallel funding partnership between the Department of Health and Wellcome Trust. The views expressed in this publication are those of the author(s) and not necessarily those of the Department of Health or Wellcome Trust. This work was supported by a Wellcome Trust Research Training Fellowship (to T.G. [103387/Z/13/Z]), a Wellcome Trust Sir Henry Postdoctoral Fellowship (to C.L. [110243/Z/15/Z] and F.C. [201344/Z/16/Z]), and an ERC grant (742158) (to J.C.)

Characteristics of Staphylococcus aureus Isolated from Patients in Busia County Referral Hospital, Kenya

Staphylococcus aureus is an important pathogen associated with hospital, community, and livestock-acquired infections, with the ability to develop resistance to antibiotics. Nasal carriage by hospital inpatients is a risk for opportunistic infections. Antibiotic susceptibility patterns, virulence genes and genetic population structure of S. aureus nasal isolates, from inpatients at Busia County Referral Hospital (BCRH) were analyzed. A total of 263 inpatients were randomly sampled, from May to July 2015. The majority of inpatients (85.9%) were treated empirically with antimicrobials, including ceftriaxone (65.8%) and metronidazole (49.8%). Thirty S. aureus isolates were cultured from 29 inpatients with a prevalence of 11% (10.3% methicillin-susceptible S. aureus (MSSA), 0.8% methicillin resistant S. aureus (MRSA)). Phenotypic and genotypic resistance was highest to penicillin-G (96.8%), trimethoprim (73.3%), and tetracycline (13.3%) with 20% of isolates classified as multidrug resistant. Virulence genes, Panton-Valentine leukocidin (pvl), toxic shock syndrome toxin-1 (tsst-1), and sasX gene were detected in 16.7%, 23.3% and 3.3% of isolates. Phylogenetic analysis showed 4 predominant clonal complexes CC152, CC8, CC80, and CC508. This study has identified that inpatients of BCRH were carriers of S. aureus harbouring virulence genes and resistance to a range of antibiotics. This may indicate a public health risk to other patients and the community

SARS-CoV-2 evolution during treatment of chronic infection

The spike protein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is critical for virus infection through the engagement of the human ACE2 protein1 and is a major antibody target. Here we show that chronic infection with SARS-CoV-2 leads to viral evolution and reduced sensitivity to neutralizing antibodies in an immunosuppressed individual treated with convalescent plasma, by generating whole-genome ultra-deep sequences for 23 time points that span 101 days and using in vitro techniques to characterize the mutations revealed by sequencing. There was little change in the overall structure of the viral population after two courses of remdesivir during the first 57 days. However, after convalescent plasma therapy, we observed large, dynamic shifts in the viral population, with the emergence of a dominant viral strain that contained a substitution (D796H) in the S2 subunit and a deletion (ΔH69/ΔV70) in the S1 N-terminal domain of the spike protein. As passively transferred serum antibodies diminished, viruses with the escape genotype were reduced in frequency, before returning during a final, unsuccessful course of convalescent plasma treatment. In vitro, the spike double mutant bearing both ΔH69/ΔV70 and D796H conferred modestly decreased sensitivity to convalescent plasma, while maintaining infectivity levels that were similar to the wild-type virus.The spike substitution mutant D796H appeared to be the main contributor to the decreased susceptibility to neutralizing antibodies, but this mutation resulted in an infectivity defect. The spike deletion mutant ΔH69/ΔV70 had a twofold higher level of infectivity than wild-type SARS-CoV-2, possibly compensating for the reduced infectivity of the D796H mutation. These data reveal strong selection on SARS-CoV-2 during convalescent plasma therapy, which is associated with the emergence of viral variants that show evidence of reduced susceptibility to neutralizing antibodies in immunosuppressed individuals

Effects of antiplatelet therapy on stroke risk by brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases: subgroup analyses of the RESTART randomised, open-label trial

Background Findings from the RESTART trial suggest that starting antiplatelet therapy might reduce the risk of recurrent symptomatic intracerebral haemorrhage compared with avoiding antiplatelet therapy. Brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases (such as cerebral microbleeds) are associated with greater risks of recurrent intracerebral haemorrhage. We did subgroup analyses of the RESTART trial to explore whether these brain imaging features modify the effects of antiplatelet therapy

SARS-CoV-2 evolution during treatment of chronic infection

SARS-CoV-2 Spike protein is critical for virus infection via engagement of ACE21, and is a major 54 antibody target. Here we report chronic SARS-CoV-2 with reduced sensitivity to neutralising 55 antibodies in an immune suppressed individual treated with convalescent plasma, generating 56 whole genome ultradeep sequences over 23 time points spanning 101 days. Little change was 57 observed in the overall viral population structure following two courses of remdesivir over the 58 first 57 days. However, following convalescent plasma therapy we observed large, dynamic 59 virus population shifts, with the emergence of a dominant viral strain bearing D796H in S2 and 60 H69/V70 in the S1 N-terminal domain NTD of the Spike protein. As passively transferred 61 serum antibodies diminished, viruses with the escape genotype diminished in frequency, before 62 returning during a final, unsuccessful course of convalescent plasma. In vitro, the Spike escape 63 double mutant bearing H69/V70 and D796H conferred modestly decreased sensitivity to 64 convalescent plasma, whilst maintaining infectivity similar to wild type. D796H appeared to be 65 the main contributor to decreased susceptibility but incurred an infectivity defect. The 66 H69/V70 single mutant had two-fold higher infectivity compared to wild type, possibly 67 compensating for the reduced infectivity of D796H. These data reveal strong selection on SARS68 CoV-2 during convalescent plasma therapy associated with emergence of viral variants with 69 evidence of reduced susceptibility to neutralising antibodies.COG-UK is supported by funding from the Medical Research Council (MRC) part of UK Research & Innovation (UKRI), the National Institute of Health Research (NIHR) and Genome Research Limited, operating as the Wellcome Sanger Institute