Biology subjects

Robotham, J. V.

Publications and source records attributed to Robotham, J. V..

4 recordsLinked to original sources

bioRxiv2024

Plasmid conjugation drives within-patient plasmid diversity

Plasmids are well known vehicles of antimicrobial resistance (AMR) genes dissemination. Through conjugation, plasmid-encoded AMR genes are spread among neighbouring bacteria, irrespective of their strain or even their species. This process is very concerning from a public health perspective, as plasmid-borne AMR gene outbreaks are often not confined to single species or strains and are therefore more difficult to be fully uncovered. At the moment, the impact of plasmid conjugation on within-patient plasmid diversity is not well understood. In this work we will tackle the role of conjugation on within-patient plasmid diversity using a dataset of carbapenemase-producing Enterobacterales (CPEs). The dataset of 256 sequences from 115 patients was sampled across England over 30 months. Each patient has more than one sequence, with at least one sequence carrying an OXA-48 gene, a well-known plasmid-borne carbapenemase-encoding gene. If more than one sequence carries the OXA-48 gene, they are carried on different bacterial hosts. Using a hybrid de novo-on-reference assembly pipeline, we were able to reconstruct the full OXA-48 plasmid from short read sequencing data for 232 of the 256 sequences. Of the 115 patients, 83 (72%) of patients had an identical OXA-48 plasmid in two or more sequences. Only 2 patients carried very different (>200 SNPs) alleles of the OXA-48 plasmid, probably from separate acquisitions. Our study shows that when more than one bacterial host carrying an OXA-48 plasmid is found in a patient, it is most likely that the same plasmid has been shared via conjugation. The event of separate acquisition of different plasmids in different bacterial hosts is highly unlikely in our dataset. Data StatementWe use data provided by Hopkins et al 2022 [16]. The data can be accessed from the National Center for Biotechnology Information (NCBI) and can be found at Bioproject Accession no. PRJNA788733. None of the data used was synthetically generated. Impact StatementConjugative plasmids are well known vessels of horizontal gene transfer, with a prominent role in the spread of antimicrobial resistance genes among different bacterial species or strains. At the epidemiological level, conjugation combined with sequencing a single colony per patient, results in plasmids outbreaks carrying antimicrobial resistance genes being found in different bacterial species and strains in different patients, potentially eluding surveillance protocols based on same bacterium/same resistance scheme. In this study we analyse within-patient plasmid diversity in a dataset with more than one sequence per patient. Only two patients show clear genomic signs of separate plasmids acquisition, while 83 patients share identical plasmids in different bacterial hosts. This points out to a very strong role of plasmid conjugation in shaping within-patient plasmid diversity.

bioinformatics↗

bioRxiv2019

When do big problems far away become smaller than the problems closer to home: Lessons for antimicrobial resistance from Father Ted

Infection prevention and control strategies aimed at reducing the occurrence of Carbapenemase-Producing Enterobacteriaceae (CPE) and other antimicrobial-resistant organisms often include advice about screening patients coming from hospitals with a known resistance problem, to prevent introductions into new hospitals by shared patients. We argue that, despite being an efficient method of identifying cases, admission screening for introduction prevention is only effective if the absolute number of imported cases from other hospitals outnumbers the cases coming from the hospitals own patient population, and therefore is only a feasible control strategy during the start of an epidemic. When determining whether import screening is still advisable, we therefore need to be continuously reminded of how Father Ted so eloquently summarised the principles of perspective: "These are small, but the ones out there are far away".

epidemiology↗

bioRxiv2019

Using hospital network-based surveillance for antimicrobial resistance as a more robust alternative to self-reporting

Hospital performance is often measured using self-reported statistics, such as the incidence of hospital-transmitted micro-organisms or those exhibiting antimicrobial resistance (AMR), encouraging hospitals with high levels to improve their performance. However, hospitals that increase screening efforts will appear to have a higher incidence and perform poorly, undermining comparison between hospitals and disincentivising testing, thus hampering infection control. We propose a surveillance system in which hospitals test patients previously discharged from other hospitals and report observed cases. Using NHS Hospital Episode Statistics data, we analysed patient movements across England and assessed the number of hospitals required to participate in such a reporting scheme to deliver robust estimates of incidence. With over 1.2 million admissions to English hospitals previously discharged from other hospitals annually, even when only a fraction of hospitals (41/155) participate (each screening at least 1000 of these admissions), the proposed surveillance system can estimate incidence across all hospitals. By reporting on other hospitals, the reporting of incidence is separated from the task of improving own performance. Therefore the incentives for increasing performance can be aligned to increase (rather than decrease) screening efforts, thus delivering both more comparable figures on the AMR problems across hospitals and improving infection control efforts.

epidemiology↗

bioRxiv2017

A National Estimate of the Health and Cost Burden of Escherichia coli Bacteraemia in the Hospital Setting: The Importance of Antibiotic Resistance.

BackgroundAntibiotic resistance poses a threat to public health and a burden to healthcare systems. Escherichia coli causes more bacteraemia cases in England than any other bacterial species, these infections, in part due to their high incidence, also pose a significant antibiotic resistance burden. The main aim of this study was to estimate the impact of E. coli bacteraemia on patient in-hospital mortality and length of stay. Secondarily, this study also aimed to estimate the effect of antibiotic resistance on these outcomes.\n\nMethods and FindingsCase patients were adult E. coli bacteraemia patients infected between July 2011 and June 2012, as reported in an English national mandatory surveillance database, with susceptibility data taken from a national laboratory surveillance database. Control patients were all non-case, adult patients with an English hospital admission record. Case and control patient characteristics and admission information were taken from NHS Digital Datasets. Resistance was defined as non-susceptible and intermediate isolates, whilst susceptible was defined as susceptible and non-tested isolates. Time to in-hospital mortality and discharge was investigated through Cox proportional hazards models. To acquire estimates of excess length of stay, multistate models were constructed, with a unit bed day cost applied to estimate cost burden. The total number of case and control hospital spells was 14,051 and 8,919,275 respectively. Acquisition of E. coli bacteraemia was associated with a statistically significant increased daily risk of in-hospital mortality, especially for the first eight days of someones hospital admission [Hazard Ratio = 2.77 (95% confidence interval; 2.61-2.94)]. Antibiotic resistance did not seem to significantly increase this risk further, though did significantly reduce risk of experiencing a discharge event (dead or alive). E.coli bacteraemia was estimated to cost {pound}14,340,900 over the study period (rounded to the nearest {pound}100), with resistance associated with excess costs per infection of {pound}220 - {pound}420 dependent on resistance type, for those where a significant impact was found (rounded to the nearest {pound}10).\n\nConclusionsE. coli bacteraemia places a significant burden on patient health and on the hospital sector in England. Resistance is an important factor on length of stay with regards to such infections.

epidemiology↗