Events on 27 September 2023

A person's immune response to previous antigen exposure is one of the most useful measures of how well their immune system is functioning. Vaccination provides a controlled and standardised exposure to an antigen, with the ability to assess immune responses prior to and after exposure. Different vaccine types can be used to explore different aspects of immune function.

Traditionally, antibody levels have been used to interrogate these responses, and it is possible to explore the quality of the antibody response and also cellular responses. A wide variability in the response to vaccination in healthy individuals can complicate interpretation of vaccine responses in patients with recurrent infections. Protection from infection is multifactorial, and while our ability to assess vaccine responses is improving, this alone is often not enough to assess an individual's immunity.

Clinical Liaison Role in Wales – an update on the journey so far

Trichophyton indotinaea is a newly described species of dermatophyte that has emerged with the last 10 years in India, and some Middle Eastern countries. It causes tinea corporis and tinea cruris mainly (ringworm infection of the torso and groin) and can spread to the arms, legs and face. T. indotineae is also characterised by a reduced susceptibility or outright resistance to one of the commonly used and otherwise highly effective antifungals, terbinafine. While high levels of cases are seen in Indida, countries outside of India and the Middle East are now seeing imported cases and the UK is not alone. Working with colleagues in London we have identified signficant numbers of cases and are now understanding how difficult these infections are to treat, even with antifungals that the organism should be sensitive to. Lesions are only superficial, but are itchy and disfiguring, and often relapse after initial antifungal therapy. We are continuing to learn about the epidemiology, transmission, diagnosis and treatment of this emerging infection.

Clostridioides difficile is responsible for the eponymous C. difficile infection (CDI). Faecal microbiota transplant (FMT), a NICE recommended treatment for recurrent CDI, is effective but logistic and safety concerns remain.

With the advent of non-donor derived products, the presentation will outline the principles and evidence related to correcting gut dysbiosis and explore whether there is a need for current or expanded FMT services in the future.

Diphtheria is a potentially fatal disease caused by strains of Corynebacterium diphtheriae, C. ulcerans or C. pseudotubercolosis that express the diphtheria toxin. It can present as a respiratory infection or as non-healing skin wounds. Diphtheria was historically most likely to be caused by C. diphtheriae. It is very rare in England (typically <10 cases per year) due to a successful routine immunisation programme. However, there has been a recent gradual increase in cases over several years, particularly cutaneous infections and those caused by toxigenic C. ulcerans strains (which can be carried by household pets).

In 2022, there was a particulary large increase in diphtheria in England, with 87 cases and 3 deaths. This included 72 toxigenic C. diphtheriae infections in asylum seekers, thought to be aquired during their travel to the UK. Symptoms ranged from severe respiratory diphtheria to cutaneous infections and asymptomatic carriage. Similar increases of C. diphtheriae infections in travelling migrants have been seen in several European countries. Some of these isolates are multidrug resistant, including to macrolides, the default recommendation for treatment, and this will require careful monitoring.

It’s life, but not as we know it. Emerging parasitic diseases

This presentation will outline the content of Paola's Clincal Case Study from her Higher Specialist Portfolio in Medical Microbiology. Here she will present the initial clinical presentation, diagnosis and treatment of a case of neonatal sepsis that linked to a previous unusual maternal screening swab. She will also outline her experience of the Higher Specialist Diploma and her plans for developing a training plan within Microbiology QMC, Nottingham for future candidates within their trust.

This presentation is based on a case study used for a portfolio of Higher Specialist Diploma awarded by the IBMS. The presentation will look at how blood cultures taken on admission helped with diagnosis and appropriate treatment of a patient. It will also go in to brief detail on the organism isolated, Streptobacillus moniliformis.

To explore the molecular profiles of Acanthamoeba from laboratory-confirmed Acanthamoeba keratitis (AK) cases reported within the United Kingdom (UK) using DNA taken directly from clinical samples.

Acanthamoeba species are free-living organisms responsible for causing a debilitating, sight-threatening disease of the cornea. Of the 24 known Acanthamoeba species, 14 cause AK.

Thirty-five Acanthamoeba DNA-positive corneal samples from the Scottish Microbiology Reference Laboratories (SMiRL), Glasgow collection were selected from cases reported from 2017 - 2019. Following extraction of the DNA directly from each clinical specimen, the DNA was subjected to in-depth molecular typing using a nested PCR / bi-directional sequencing approach.

Molecular profiling was successful for 32 samples which comprised of two genotypes namely T3 and T4. The T4 genotype were further sub-typed; five sub-types existed namely; T4A, T4B, T4C, T4E and T4F.

Using a molecular typing assay applied directly to corneal tissue, this study highlights the T4 genotype and the T4A subtype are the predominant molecular variants of Acanthamoeba to cause ocular disease in the UK. Gaining in-depth information on the molecular profiling of Acanthamoeba is essential to increase our knowledge and understanding of the epidemiology, transmission pathways and potential associations with clinical outcomes for this rare, yet potentially debilitating ocular disease.

Antimicrobial resistance (AMR) in anaerobic bacteria varies greatly between institutions and countries. It is crucial that we have robust and widely available methods and perform regular surveillance to raise awareness of AMR amongst laboratory and clinical teams.

The UKARU offers a UK-wide service for the identification and antimicrobial susceptibility testing (AST) of anaerobic clinical isolates. Since 2016, this service has included weekly AST by agar dilution. The MIC population distributions for isolates referred are presented in real time via the ARUMIC platform, facilitating continuous monitoring of the development of resistance and valuable data for the review and development of epidemiological cut-offs (ECOFFs) and species-specific breakpoints, alongside the European Committee for Antimicrobial Susceptibility Testing (EUCAST).

During 2017 – 2021 EUCAST and the UKARU reviewed the AST methodology and breakpoints for anaerobes and developed a standardised disk diffusion method. Fastidious Anaerobe Agar with horse blood (FAA-HB) was used to test the most commonly isolated anaerobic bacteria including Bacteroides spp (n=170), Prevotella spp. (n=49), Fusobacterium necrophorum (n=51), Clostridium perfringens (n=58) and Cutibacterium acnes(n=54). The antimicrobials included for the initial phase were benzylpenicillin, piperacillin-tazobactam, meropenem, metronidazole and clindamycin with vancomycin included for the Gram positive organisms. Breakpoints for additional agents have just been published on the EUCAST website.

This lecture will provide insights into the development of AMR in anaerobic bacteria, the available AST methodologies and the importance of surveillance for this important group of pathogens.