Publications by authors named "V J Chalker"
Currently there is no detailed, internationally agreed protocol defined to evaluate antimicrobial susceptibility testing (AST) for Legionella pneumophila (required to establish epidemiological cut-off value or "ECOFF" boundaries); therefore, antimicrobial resistance in these isolates cannot be defined. AST methods utilising media containing activated charcoal as an ingredient, to enable Legionella growth, are unreliable as noted in an internationally authored opinion paper and a new gold standard is required. Here we define a detailed protocol for broth microdilution (BMD) using defined cell culture collection-deposited control reference strains (Philadelphia-1 and Knoxville-1) as well as two accessible reference strains with moderately (lpeAB-carrying) and markedly (23S rRNA mutation-carrying) elevated azithromycin minimum inhibitory concentration (MIC).
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- Streptococcus mitis is a major contributor to infective endocarditis (IE), but its genetics and disease-causing abilities are not well understood due to the disease's rarity.
- Researchers conducted whole genome sequencing on 129 S. mitis samples from UK bloodstream infections over 15 years, finding a high level of genetic diversity among isolates without a single dominant lineage.
- The study identified a variable presence of virulence genes, suggesting that S. mitis acts as an accidental pathogen in IE cases rather than being driven by specific resistant or aggressive strains.
Asthma is a significant public health concern, particularly in children with severe symptoms. Exacerbation of asthma (EOA) is life-threatening, and respiratory infections (RIs) play a crucial role. Though viruses play a significant role in EOA, patients are empirically treated with antibiotics, contributing to antibiotic resistance development.
View Article and Find Full Text PDFStreptococcus suis, a zoonotic bacterial pathogen circulated through swine, can cause severe infections in humans. Because human S. suis infections are not notifiable in most countries, incidence is underestimated.
View Article and Find Full Text PDFIntroduction: Antimicrobial resistance (AMR) is a global threat that necessitates coordinated strategies to improve antibiotic prescribing and reduce AMR. A key activity is ascertaining current prescribing patterns in hospitals to identify targets for quality improvement programmes.
Methods: The World Health Organisation point prevalence survey methodology was used to assess antibiotic prescribing in the Cape Coast Teaching Hospital.