ALLSA

CURRENT ALLERGY & CLINICAL IMMUNOLOGY JOURNAL OF THE ALLERGY SOCIETY OF SOUTH AFRICA

Vol 37, No 2 June 2024

  • THE MICROBIOME
  • Diet and the gut microbiome
  • The microbiome’s impact on skin health and disease
  • Prescribing probiotic drugs
  • Fermented foods and allergy protection
  • Secretory IgA
  • Clostridiodes difficile in a young girl
  • Occupational contact dermatitis
  • Exploring the feasibility of occupational allergy surveillance using routine public-health data
  • Prescribing antimicrobial drugs ethically
  • Ethics and the microbiome

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GUEST EDITORIAL

Author: Pieter de Waal

Abstract: Welcome to the intrigue of the fascinating biosphere called the “Human Microbiome” – a catalogue of trillions of bacteria, fungi, viruses and other singlecelled organisms (and their genes), in and on areas such as the skin, mouth, gastrointestinal, respiratory and urogenital tracts and deservingly being pointed out as the forgotten organ!

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REVIEW ARTICLE
DIET AND THE GUT MICROBIOME IN THE PREVENTION AND DEVELOPMENT OF FOODALLERGIC DISEASE

Author: Idonette van Zyl

Abstract: Allergic disease affects individual health and family quality of life greatly. Food allergy and prevention strategies have been researched for many years. The gut microbiome has been associated with food allergy outcomes. Increased diet variety has been associated with improved gastrointestinal health and increased levels of gut microbial diversity. Such a variety includes a high intake of fibrous plant-based foods, including vegetables, fruit, whole grains, legumes, nuts and seeds, and a reduced intake of ultra-processed foods. Diet diversity influences the microbiome and gut epithelial immune indices and has recently been proven to be an effective allergy-prevention strategy. In the area of food-allergy prevention, approaches to diet diversity require further research in order to define effective strategies.

Keywords: food allergy, gut microbiome, first thousand days, diet diversity, fibre

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Review article
THE MICROBIOMEʼS IMPACT ON SKIN HEALTH AND DISEASE

Author: Susanna MH Kannenberg

Abstract: The skin is the outermost organ of the human body and serves as a protective barrier against external pathogens and environmental factors. It is colonised by a diverse community of microorganisms, collectively known as the skin microbiome. From birth to death, the skin undergoes dynamic changes in microbial composition influenced by endogenous physiological host factors, environmental exposure and various diseases. These microorganisms play a crucial role in maintaining the health and functionality of the skin. They contribute to the education and moderation of the immune system, protect against pathogenic invaders and regulate various physiological processes, such as maintaining a healthy barrier. Dysbiosis, characterised by microbial imbalance, is associated with various skin disorders, among others atopic dermatitis and acne vulgaris. In recent years, interest has been growing in understanding the role of the skin microbiome in health and disease. Understanding these complex interactions has led to the development of novel therapeutic approaches that target the skin microbiome, including prebiotic and probiotic therapy. This article provides an overview of the current knowledge of the skin microbiome and its impact on human health and disease.

Keywords: microbiome, dysbiosis, colonisation, commensal, atopic dermatitis, acne vulgaris

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Review article
PRESCRIBING PROBIOTIC DRUGS IN CLINICAL PRACTICE – ARE THEY INDICATED?

Authors: André van Niekerk, Suzanne D Delport

Abstract: The past two decades will be remembered for the rapid advances in our understanding of the significant role that the human microbiome plays in health, illness and longevity, but it remains a vast concept, one that is largely uncharted. Its contribution to human health is brought about by a myriad microbiome-associated physiological mechanisms complemented by its genetic ability, which is around 150 times that of the human genome. Many strategies are being devised to ‘engineer’ or augment an unfavourable microbiome. The use of probiotic products represents one of these strategies since they can augment the gut microbiome and improve health. However, their correct, effective and safe use is clouded by many variables. Probiotic drugs are used for two main reasons: mostly to improve general health but also in some illnesses for which evidence has been generated. The use of probiotic products to maintain general health is in most instances not supported by scientific evidence. Precision in the reconstitution of an unfavourable microbiome as in disease or the maintenance of a favourable microbiomeis the ultimate goal. This is not possible at the bedside because of an incomplete understanding of the human microbiome. This could lead in turn to the overuse of unregulated probiotic products which may be ineffective or even harmful, as in the case of immunocompromised individuals. The aim of this article is to offer guidance on current best practices in prescribing probiotic drugs.

Keywords: probiotic drugs, prescribing

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Review article
FERMENTED FOODS AND ALLERGY PROTECTION: LESSONS FROM RURAL COMMUNITIES

Authors: Pieter de Waal, Evette van Niekerk

Abstract: Marked differences in the prevalence of allergy between urban and rural environments have been well established. Certain microorganisms encountered in and around farming and rural surroundings can ‘train’ and modulate the human immune system to protect against certain infectious and non-communicable diseases, including allergies. Research from South Africa has indicated that drinking fermented cow’s milk from a young age may protect against allergy even in a urban population. Lactic acid bacteria are important role-players in allergy protection and these organisms are abundant in fermented food products. The questions arise: Can people living in urban areas, at least to some extent, ‘replicate’ the allergy protective environment of rural people or at least compensate for a lack of exposure to protective organisms? And can they do so safely? In this review we focus on fermented milk and other fermented foods and elaborate on the allergyprotective microbiota favoured by fermentation.

Keywords: fermented foods, lactic acid bacteria, probiotics, microbiome, food allergies, immune modulation, microbial diversity, metabolites

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Review article
SECRETORY IgA – GUARDIAN OF THE GUT MICROBIOME GALAXY

Author: Eftyhia Vardas

Abstract: Secretory immunoglobulin A (SIgA) and mucosal immunity are neglected topics in immunology. This may be because mucosal immunity is a new and growing area of research for which the clinical implications and measurable diagnostic biomarkers are still developing. Alternatively, it could be a result of the misconception that SIgA is the same as circulating IgA, which presents as a relatively mild phenotype of isolated IgA deficiency in the realm of antibody deficiencies. This article outlines the role SIgA plays in mucosal immunity as the most abundantly produced antibody isotype in human beings and its function as a multitasking antibody that orchestrates the protection of mucosal surfaces, in particular the vast gut mucosa, against environmental insults, toxins and infections. SIgA is the key to immune tolerance and homeostasis as it enables the symbiotic relationship with the complex human microbiome for human health. The currently known clinical implications are highlighted in disease states in which there is dysbiosis with associated deficiencies or dysfunction of SIgA, including certain infectious conditions and well-known clinical conditions such as IgA nephropathy, inflammatory bowel diseases, allergy and some autoimmune diseases. Measuring mucosal immunity and microbiome health is challenging, but methods and biomarkers are available that can be carried out relatively easily in diagnostic laboratories.

Keywords: secretory IgA, mucosal immunity, misconceptions

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Case Report
CLOSTRIDIODES DIFFICILE IN A YOUNG GIRL

Author: Silvia Strobele

Abstract: Clostridiodes difficile (C. diff), previously known as Clostridium difficile, is the leading cause of healthcare-related diarrhoea. Many risk factors have been identified, including frequent exposure to healthcare systems, antibiotic exposure, exposure to proton pump inhibitors (PPI) and underlying chronic gastrointestinal diseases. An accurate diagnosis may be difficult because asymptomatic colonisation often exists. Treatment guidelines are also not fully standardised, especially not in the case of children. A faecal microbiota transplant is recommended for recurrent and severe cases and after careful patient selection; however, this treatment modality has many practical challenges. The author warns against the over-eager prescription of antibiotics, especially to treat viral infections, as this is a common predisposition to C. diff in children and adults.

Keywords: C. diff, Clostridiodes difficile, microbiome, dysbiosis, faecal transplant

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Allergies in the Workplace
EXPLORING THE FEASIBILITY OF OCCUPATIONAL ALLERGY SURVEILLANCE USING ROUTINE PUBLIC-HEALTH DATA: A RETROSPECTIVE ANALYSIS

Authors: Edith Ratshikhopha, Munyadziwa Muvhali, Nisha Naicker, Tanusha Singh

Abstract: This retrospective study aimed to assess allergic sensitisation among adult patients tested at National Health Laboratory Service (NHLS) laboratories across nine provinces in South Africa. With a primary focus on identifying prevalent allergens, the investigation extends to comparative analyses with workers tested at the National Institute for Occupational Health (NIOH) and explores trends during a ten-year period from 2012. The overarching objective was to ascertain the potential value of leveraging routine public-health data for comprehensive occupational allergy (OA) surveillance, attempting to fill a critical gap in existing South African OA data. In examining allergic sensitisation, the study spanned NHLS laboratory tests conducted from January 2012 to December 2021, encompassing adult demographic ages from 18 to 65 years, which represent the typical working age of South Africans. The results for allergens recommended by the South African Allergic Rhinitis Working Group and other allergens of relevance in occupational settings were extracted and analysed, providing a robust foundation for a nuanced exploration of sensitisation patterns. Of the 31 913 NHLS laboratory records, 48.48% of adults tested positive for ImmunoCAP Phadiatop, indicative of atopy. In addition, the percentage sensitisation to common aeroallergens of 538 workers tested at the NIOH using the skin-prick test method was compared to those of patients tested at the NHLS. Furthermore, the study uncovered a spectrum of sensitisation patterns, with house-dust mites and grass pollens emerging as predominant allergens. Occupational allergens, including latex, alpha-amylase and chlorhexidine, manifested as noteworthy contributors to sensitisation, shedding light on potential workplace hazards. Provincial variations in sensitisation patterns underscore the nuanced nature of allergic responses across different regions. Dermatophagoides pteronyssinus dominated in five provinces, signifying geographical disparities in allergen prevalence. Intriguingly, comparison with NIOH data reveals significantly higher sensitisation rates in NHLS patients for specific allergens, which suggests potential variations in testing methodologies and patient selection between the two institutions. Drawing from these insights, the study concluded that routine NHLS data are of critical importance for trend analysis and preventive strategies. The high prevalence of sensitisation to common allergens underscores the imperative for targeted preventive measures. This study, bridging the gap in OA data, lays the groundwork for future research exploring the intricate associations between routine allergen sensitisation testing and OA surveillance.

Keywords: allergic sensitisation, respiratory allergy, public-health data, occupational allergy surveillance

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Case Report
OCCUPATIONAL CONTACT DERMATITIS DUE TO ORGANIC BROMINE COMPOUNDS

Authors: Pere Sanz-Gallen, Carme Barrot, Inmaculada Herrera-Mozo, Susana Pujalte, Aureli Rodriguez-Lagunas

Introduction: Organic bromide compounds are widely used in industry and some of them, such as methyl bromide, are highly toxic. They are mainly used as flame retardant compounds, biocides and chemical synthesis intermediates.
Case report: In this study we report on three cases of contact dermatitis, two of them allergic dermatitis to biocides in the workplace (methyl dibromoglutaronitrile (MDBGN) and bronopol). The third case is a severe irritant dermatitis in a veterinary laboratory worker who used 6-bromo-1-hexanol as a synthetic intermediate to obtain pheromones.
Conclusion: It is very important to detect the agent or agents causing contact dermatitis in order to implement the appropriate preventive measures to avoid the appearance of new cases or relapses of cases already diagnosed.

Keywords: bromine organic compounds, biocides, 6-bromo-1-hexanol, contact dermatitis

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Ethics article
PRESCRIBING ANTIMICROBIAL DRUGS ETHICALLY

Author: Marc Blockman

Abstract: Antimicrobial resistance (AMR) is a global health challenge that threatens the effective prevention and treatment of an ever-increasing range of infections. The overuse and misuse of antimicrobials are major drivers of this crisis, leading to the emergence of multi-drug-resistant organisms (MDR). AMR increases morbidity and mortality and is associated with high costs to the economy due to its burden on healthcare. Infections with MDR bacteria also have substantial implications for clinical and economic outcomes. Globally, more than a million people die each year from bacterial-resistant infections, which may rise to 10 million by 2050 unless effective action is taken. Collective action is critical as AMR has an impact on global health and action (or inaction) contributes to the overall AMR burden. This is echoed by Dr Tedros Adhanom Ghebreyesus, Director-General of the World Health Organization: ‘As we gather more evidence, we see more clearly and more worryingly how fast we are losing critically important antimicrobial medicines all over the world.’

Keywords: ethics, antimicrobial resistance, antimicrobial stewardship

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Ethics article
ETHICS AND THE MICROBIOME

Author: Sharon Kling

Abstract: The human microbiome and research linked to it have become increasingly important in our discourse about allergy and asthma and numerous other diseases. Accompanying this research and its applications are a host of ethical, legal and social implications, though. In this article I draw on the work of experts in the field and attempt to provide some clarification on these issues.

Keywords: microbiome, ethics

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DR SPUR’S MYSTERY CASE
PRIMARY IMMUNODEFICIENCY DISORDERS

Authors: Sylvia van den Berg, Marieke Brauer, André van Niekerk

Abstract: The human microbiome is indeed a fascinating subject, with new research and insights and promising tools for management emerging in the field.

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ABC of Allergy
Microorganisms of the Skin

Authors: Shaunagh Emanuel and Di Hawarden

Abstract: Dr Do-a-lot presents a case of a young woman with periorificial dermatitis that reports having noticed a rash that appeared around her nose and lips following the use of a new daily cosmetic concealer. When she self-treated the rash with a mild topical corticosteroid cream it tended to settle, but returned with renewed vigour every time she withdrew the steroid treatment. Discussion around the management of her condition includes measures to restore a heathy microbiome in the area.

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