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"Wong, Vanessa K."
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A systematic review of antimicrobial resistance in Salmonella enterica serovar Typhi, the etiological agent of typhoid
by
Britto, Carl D.
,
Dougan, Gordan
,
Pollard, Andrew J.
in
Anti-Bacterial Agents - pharmacology
,
Antiinfectives and antibacterials
,
Antimicrobial agents
2018
The temporal and spatial change in trends of antimicrobial resistance (AMR) in typhoid have not been systematically studied, and such information will be critical for defining intervention, as well as planning sustainable prevention strategies.
To identify the phenotypic trends in AMR, 13,833 individual S. Typhi isolates, reported from 1973 to 2018 in 62 publications, were analysed to determine the AMR preponderance over time. Separate analyses of molecular resistance determinants present in over 4,000 isolates reported in 61 publications were also conducted. Multi-drug resistant (MDR) typhoid is in decline in Asia in a setting of high fluoroquinolone resistance while it is on the increase in Africa. Mutations in QRDRs in gyrA (S83F, D87N) and parC (S80I) are the most common mechanisms responsible for fluoroquinolone resistance. Cephalosporin resistant S. Typhi, dubbed extensively drug-resistant (XDR) is a real threat and underscores the urgency in deploying the Vi-conjugate vaccines.
From these observations, it appears that AMR in S. Typhi will continue to emerge leading to treatment failure, changes in antimicrobial policy and further resistance developing in S. Typhi isolates and other Gram-negative bacteria in endemic regions. The deployment of typhoid conjugate vaccines to control the disease in endemic regions may be the best defence.
Journal Article
Emergence of an Extensively Drug-Resistant Salmonella enterica Serovar Typhi Clone Harboring a Promiscuous Plasmid Encoding Resistance to Fluoroquinolones and Third-Generation Cephalosporins
by
Hasan, Rumina
,
Saleem, Muhammad Khalid
,
Klemm, Elizabeth J.
in
Anti-Bacterial Agents - pharmacology
,
Cephalosporins - pharmacology
,
Drug Resistance, Multiple, Bacterial
2018
Antibiotic resistance is a major problem in Salmonella enterica serovar Typhi, the causative agent of typhoid. Multidrug-resistant (MDR) isolates are prevalent in parts of Asia and Africa and are often associated with the dominant H58 haplotype. Reduced susceptibility to fluoroquinolones is also widespread, and sporadic cases of resistance to third-generation cephalosporins or azithromycin have also been reported. Here, we report the first large-scale emergence and spread of a novel S . Typhi clone harboring resistance to three first-line drugs (chloramphenicol, ampicillin, and trimethoprim-sulfamethoxazole) as well as fluoroquinolones and third-generation cephalosporins in Sindh, Pakistan, which we classify as extensively drug resistant (XDR). Over 300 XDR typhoid cases have emerged in Sindh, Pakistan, since November 2016. Additionally, a single case of travel-associated XDR typhoid has recently been identified in the United Kingdom. Whole-genome sequencing of over 80 of the XDR isolates revealed remarkable genetic clonality and sequence conservation, identified a large number of resistance determinants, and showed that these isolates were of haplotype H58. The XDR S . Typhi clone encodes a chromosomally located resistance region and harbors a plasmid encoding additional resistance elements, including the bla CTX-M-15 extended-spectrum β-lactamase, and carrying the qnrS fluoroquinolone resistance gene. This antibiotic resistance-associated IncY plasmid exhibited high sequence identity to plasmids found in other enteric bacteria isolated from widely distributed geographic locations. This study highlights three concerning problems: the receding antibiotic arsenal for typhoid treatment, the ability of S . Typhi to transform from MDR to XDR in a single step by acquisition of a plasmid, and the ability of XDR clones to spread globally. IMPORTANCE Typhoid fever is a severe disease caused by the Gram-negative bacterium Salmonella enterica serovar Typhi. Antibiotic-resistant S . Typhi strains have become increasingly common. Here, we report the first large-scale emergence and spread of a novel extensively drug-resistant (XDR) S . Typhi clone in Sindh, Pakistan. The XDR S . Typhi is resistant to the majority of drugs available for the treatment of typhoid fever. This study highlights the evolving threat of antibiotic resistance in S . Typhi and the value of antibiotic susceptibility testing and whole-genome sequencing in understanding emerging infectious diseases. We genetically characterized the XDR S . Typhi to investigate the phylogenetic relationship between these isolates and a global collection of S . Typhi isolates and to identify multiple genes linked to antibiotic resistance. This S . Typhi clone harbored a promiscuous antibiotic resistance plasmid previously identified in other enteric bacteria. The increasing antibiotic resistance in S . Typhi observed here adds urgency to the need for typhoid prevention measures. Typhoid fever is a severe disease caused by the Gram-negative bacterium Salmonella enterica serovar Typhi. Antibiotic-resistant S . Typhi strains have become increasingly common. Here, we report the first large-scale emergence and spread of a novel extensively drug-resistant (XDR) S . Typhi clone in Sindh, Pakistan. The XDR S . Typhi is resistant to the majority of drugs available for the treatment of typhoid fever. This study highlights the evolving threat of antibiotic resistance in S . Typhi and the value of antibiotic susceptibility testing and whole-genome sequencing in understanding emerging infectious diseases. We genetically characterized the XDR S . Typhi to investigate the phylogenetic relationship between these isolates and a global collection of S . Typhi isolates and to identify multiple genes linked to antibiotic resistance. This S . Typhi clone harbored a promiscuous antibiotic resistance plasmid previously identified in other enteric bacteria. The increasing antibiotic resistance in S . Typhi observed here adds urgency to the need for typhoid prevention measures.
Journal Article
A global resource for genomic predictions of antimicrobial resistance and surveillance of Salmonella Typhi at pathogenwatch
2021
As whole-genome sequencing capacity becomes increasingly decentralized, there is a growing opportunity for collaboration and the sharing of surveillance data within and between countries to inform typhoid control policies. This vision requires free, community-driven tools that facilitate access to genomic data for public health on a global scale. Here we present the Pathogenwatch scheme for
Salmonella enterica
serovar Typhi (
S
. Typhi), a web application enabling the rapid identification of genomic markers of antimicrobial resistance (AMR) and contextualization with public genomic data. We show that the clustering of
S
. Typhi genomes in Pathogenwatch is comparable to established bioinformatics methods, and that genomic predictions of AMR are highly concordant with phenotypic susceptibility data. We demonstrate the public health utility of Pathogenwatch with examples selected from >4,300 public genomes available in the application. Pathogenwatch provides an intuitive entry point to monitor of the emergence and spread of
S
. Typhi high risk clones.
Whole genome sequencing data are increasingly becoming routinely available but generating actionable insights is challenging. Here, the authors describe Pathogenwatch, a web tool for genomic surveillance of
S.
Typhi, and demonstrate its use for antimicrobial resistance assignment and strain risk assessment.
Journal Article
An extended genotyping framework for Salmonella enterica serovar Typhi, the cause of human typhoid
2016
The population of
Salmonella enterica
serovar Typhi (
S.
Typhi), the causative agent of typhoid fever, exhibits limited DNA sequence variation, which complicates efforts to rationally discriminate individual isolates. Here we utilize data from whole-genome sequences (WGS) of nearly 2,000 isolates sourced from over 60 countries to generate a robust genotyping scheme that is phylogenetically informative and compatible with a range of assays. These data show that, with the exception of the rapidly disseminating H58 subclade (now designated genotype 4.3.1), the global
S
. Typhi population is highly structured and includes dozens of subclades that display geographical restriction. The genotyping approach presented here can be used to interrogate local
S.
Typhi populations and help identify recent introductions of
S
. Typhi into new or previously endemic locations, providing information on their likely geographical source. This approach can be used to classify clinical isolates and provides a universal framework for further experimental investigations.
Typhoid fever is caused by
Salmonella enterica
serovar Typhi (S. Typhi). This study examines ∼2,000 clinical isolates of
S
. Typhi to show highly structured/geographically restricted genomes except rapidly disseminating H58 subclade, and design a genotyping framework for tracking the disease.
Journal Article
Review of Foodborne Botulism in the UK: 2006–2024
by
Godbole, Gauri
,
Ahmed, Burhan
,
Amar, Corinne Francoise Laurence
in
Airway management
,
Bioassays
,
Botulinum toxin
2025
Food-borne botulism is a rare but serious disease caused by ingestion of botulinum neurotoxin pre-formed in food by Clostridium botulinum. Between 2006 and 2009, no foodborne botulism cases were reported in the UK. However, the period from 2010 to 2024 saw 13 cases, encompassing seven separate incidents and two outbreaks, with no reported fatalities. Cases were predominantly linked to imported, home-made, and artisanal foods, occasionally to commercial products. Diagnostic and public health challenges include delayed clinical diagnosis, delayed sample collection, inadequate specimen volumes, and the frequent unavailability of suspected food sources, hampering epidemiological investigations. The UK has an extremely low incidence of foodborne botulism with an estimated rate of 0.001 cases per 100,000 people per year, but despite this low occurrence, food botulism remains a public health emergency as it requires timely treatment and rapid reactive intervention to be undertaken by multiple regulatory agencies. Continuous professional training of medical staff, up-to-date clinical guidance, rapid diagnostic, and food investigations are essential for optimising patient outcomes and prevention.
Journal Article
Emergence of dominant multidrug-resistant bacterial clades
by
Dougan, Gordon
,
Wong, Vanessa K.
,
Klemm, Elizabeth J.
in
Anti-Bacterial Agents - pharmacology
,
Antibiotic resistance
,
Antibiotics
2018
Antibiotic resistance in bacteria has emerged as a global challenge over the past 90 years, compromising our ability to effectively treat infections. There has been a dramatic increase in antibiotic resistance-associated determinants in bacterial populations, driven by the mobility and infectious nature of such determinants. Bacterial genome flexibility and antibiotic-driven selection are at the root of the problem. Genome evolution and the emergence of highly successful multidrug-resistant clades in different pathogens have made this a global challenge. Here, we describe some of the factors driving the origin, evolution, and spread of the antibiotic resistance genotype.
Journal Article
A mycotic aneurysm related to Salmonella Rissen infection: a case report
2020
Background
Salmonella
species commonly causes infection in humans and on occasion leads to serious complications, such as mycotic aneurysms. Here, we present the first case reported of a patient with a mycotic aneurysm likely secondary to
Salmonella
Rissen infection.
Case presentation
The patient presented with 4 weeks of lower back pain, chills and a single episode of diarrhoea 2 months prior during a 14-day trip to Hong Kong and Taiwan. Magnetic resonance imaging revealed an aneurysmal left internal iliac artery with adjacent left iliacus rim-enhancing collection. A stool culture was positive for
Salmonella
Rissen ST 469 EBG 66 on whole genome sequencing. The patient underwent an emergency bifurcated graft of his internal iliac aneurysm and was successfully treated with appropriate antibiotics.
Conclusions
This case highlights the importance of considering the diagnosis of a mycotic aneurysm in an unusual presentation of back pain with features of infection.
Journal Article
Being in a “Green” Building Elicits “Greener” Recycling, but Not Necessarily “Better” Recycling
by
Wu, David W.-L.
,
Kingstone, Alan
,
Wong, Vanessa K.
in
Atmospherics
,
Behavior
,
Built environment
2016
Previous observational work revealed that transient populations in a sustainable building disposed of waste more accurately when compared to patrons in a non-sustainable building. The current study uses an experimental design to replicate this observed effect and to investigate whether or not the built environment influences motivational factors to impact behavior. We find support that a building designed and built to communicate an atmosphere of sustainability can influence waste disposal behavior. Participants in the sustainable building used the garbage receptacle significantly less and compensated by tending to select the containers and organics receptacle more, which actually resulted in more errors overall. Our findings suggest that building atmospherics can motivate people to recycle more. However, atmospherics alone do not appear to be sufficient to elicit the desired performance outcome.
Journal Article
Low respiratory quotient correlates with high mortality in patients undergoing mechanical ventilation
2024
Oxygen consumption (VO2), carbon dioxide generation (VCO2), and respiratory quotient (RQ), which is the ratio of VO2 to VCO2, are critical indicators of human metabolism. To seek a link between the patient's metabolism and pathophysiology of critical illness, we investigated the correlation of these values with mortality in critical care patients.
This was a prospective, observational study conducted at a suburban, quaternary care teaching hospital. Age 18 years or older healthy volunteers and patients who underwent mechanical ventilation were enrolled. A high-fidelity automation device, which accuracy is equivalent to the gold standard Douglas Bag technique, was used to measure VO2, VCO2, and RQ at a wide range of fraction of inspired oxygen (FIO2).
We included a total of 21 subjects including 8 post-cardiothoracic surgery patients, 7 intensive care patients, 3 patients from the emergency room, and 3 healthy volunteers. This study included 10 critical care patients, whose metabolic measurements were performed in the ER and ICU, and 6 died. VO2, VCO2, and RQ of survivors were 282 +/− 95 mL/min, 202 +/− 81 mL/min, and 0.70 +/− 0.10, and those of non-survivors were 240 +/− 87 mL/min, 140 +/− 66 mL/min, and 0.57 +/− 0.08 (p = 0.34, p = 0.10, and p < 0.01), respectively. The difference of RQ was statistically significant (p < 0.01) and it remained significant when the subjects with FIO2 < 0.5 were excluded (p < 0.05).
Low RQ correlated with high mortality, which may potentially indicate a decompensation of the oxygen metabolism in critically ill patients.
Journal Article
Continuous and repeat metabolic measurements compared between post-cardiothoracic surgery and critical care patients
by
Becker, Lance B.
,
Molmenti, Ernesto P.
,
Lampe, Joshua W.
in
Accuracy
,
Analysis
,
Artificial respiration
2023
Objective
Using a system, which accuracy is equivalent to the gold standard Douglas Bag (DB) technique for measuring oxygen consumption (VO
2
), carbon dioxide generation (VCO
2
), and respiratory quotient (RQ), we aimed to continuously measure these metabolic indicators and compare the values between post-cardiothoracic surgery and critical care patients.
Methods
This was a prospective, observational study conducted at a suburban, quaternary care teaching hospital. Age 18 years or older patients who underwent mechanical ventilation were enrolled.
Results
We included 4 post-surgery and 6 critical care patients. Of those, 3 critical care patients died. The longest measurement reached to 12 h and 15 min and 50 cycles of repeat measurements were performed. VO
2
of the post-surgery patients were 234 ± 14, 262 ± 27, 212 ± 16, and 192 ± 20 mL/min, and those of critical care patients were 122 ± 20, 189 ± 9, 191 ± 7, 191 ± 24, 212 ± 12, and 135 ± 21 mL/min, respectively. The value of VO
2
was more variable in the post-surgery patients and the range of each patient was 44, 126, 71, and 67, respectively. SOFA scores were higher in non-survivors and there were negative correlations of RQ with SOFA.
Conclusions
We developed an accurate system that enables continuous and repeat measurements of VO
2
, VCO
2
, and RQ. Critical care patients may have less activity in metabolism represented by less variable values of VO
2
and VCO
2
over time as compared to those of post-cardiothoracic surgery patients. Additionally, an alteration of these values may mean a systemic distinction of the metabolism of critically ill patients.
Journal Article