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14 April 2023 | Story Prof Robert Bragg, Wanja Swart and Samantha Mc Carlie | Photo Supplied
Prof Robert Bragg, Wanja Swart, and Samantha Mc Carlie
Prof Robert Bragg, Wanja Swart, and Samantha Mc Carlie are from the Infection Control Group within the Veterinary Biotechnology Research Group, Department of Microbiology and Biochemistry, University of the Free State.

Opinion article by Prof Robert Bragg, Wanja Swart, and Samantha Mc Carlie, Infection Control Group within the Veterinary Biotechnology Research Group, Department of Microbiology and Biochemistry, University of the Free State.

The storm is coming, and it has, in fact, already had significant effects in health care and agriculture. This is the storm of resistance to disinfectants. 

In the age where antibiotics are ever decreasing in efficacy and the search for novel antimicrobials is not progressing very well, our last line of defence against bacterial diseases is biosecurity. Biosecurity is the concept of preventing the infection before the individual becomes infected. The individual can be human, animal or plant. The main weapons in the arsenal for good biosecurity are disinfectants and sanitisers, of which there are many. In fact, way too many! Many of these disinfectants are not used correctly, and in many cases, there is no effort to monitor the efficacy of the disinfectants used in a particular situation. Many of these are not registered for use and have never been tested in a clinical setting. This is a big part of the problem.

Antibiotic resistance is a well-known global crisis currently challenging the healthcare community. However, the COVID-19 pandemic has highlighted our reliance on disinfectants and sanitisers as infection control measures. In 2020 alone, it was estimated that 700 000 tons of quaternary ammonium compound (QAC)-based disinfectants were released into the environment. The presence of these disinfectants environmentally leads to selection for resistant microorganisms and can lead to the development of resistant populations in our water systems, on farms, and around hospitals. This has prompted the Infection Control research group at the UFS to explore new research regarding microbial resistance to disinfectant and sanitiser compounds, as well as whether resistance to disinfectants and antibiotics is linked. 

The coming storm in health care

Nosocomial infections, otherwise known as hospital-acquired infections (HAIs), affect 30% of ICU patients in high-income countries and up to 70% in low-income countries, with more than 52% of these infections being fatal. According to the World Health Organisation (WHO), HAIs are also responsible for up to 56% of all deaths in neonates. 

In 2014, an article was published with a powerful title: The future if we do not act now, where the author stated that if we do not address antimicrobial resistance (AMR), it will be responsible for the death of 10 million individuals by the year 2050, which would make it a bigger killer than cancer today. This information was widely regarded as an over-dramatisation as, at the time, AMR was estimated to have claimed the lives of 700 000 individuals annually. However, the WHO estimated that AMR was directly responsible for 1,27 million deaths in 2019 and 4,95 million deaths in 2022. It is now becoming abundantly clear that this article was not an over-dramatisation, and the number of 10 million mortalities will be reached long before 2050. We are already halfway there in 2022.

With health care being the environment where most cases of AMR and HAIs occur in conjunction, it is concerning that research is underway that shows exponential increases in resistance when bacteria are exposed to sub-minimum levels of disinfectants regularly used within the health-care setting.

The coming storm in agriculture

The need to reduce the use of antibiotics in agriculture has been in place for several years now. The concept of biosecurity is well established in the agricultural sector, but disinfectants are still being misused. It is difficult to produce meat products without the use of antibiotics; this will result in an increase in the cost of meat products, which will put it beyond the reach of many people. Good biosecurity is essential in the animal production area, and this research group has been working in the area for many years. The experience gained in this field is now being applied to the healthcare setting. If we can reduce mortalities in a poultry pen by 56% through good biosecurity prevention practices, it should certainly be possible to achieve similar or much better results in the health-care sector. 

Research on the mechanisms of disinfectant resistance

Current projects in Prof Robert Bragg’s laboratory include a PhD by Samantha Mc Carlie, investigating how bacteria become resistant to disinfectant and sanitiser products. A highly resistant ‘superbug’ bacterium related to Serratia marcescens has been discovered, and Mc Carlie is working with this isolate to determine the reason for the high level of resistance to disinfectant and sanitiser products. This work is being done on a genetic level to reveal which resistance genes and metabolic systems are responsible for high levels of antimicrobial resistance. Master of Science (MSc) projects by Boudine van der Walt and Wanja Swart are investigating how disinfectant resistance is transferred between bacterial species, and whether disinfectant resistance and antibiotic resistance are linked. Wanja Swart’s MSc project focuses on investigating the simultaneous development of antibiotic and disinfectant resistance within one bacterium. Resistance occurs despite the absence of one of these products in a familiar nosocomial pathogen, Serratia marcescens. Gene-based analysis will shed light on how these mechanisms present on a genetic level. In addition, resistance to disinfectants and antibiotics may be inducted to higher levels, which could provide new insights to just how dangerous incorrectly used disinfectants can be.

Gunther Staats has just completed yet another MSc project, focusing on efflux pumps that pump out antimicrobial agents from the inside of bacterial cells. 


Evaluation of the efficacy of disinfectants 

Registration of disinfectants, where applicable, has specific guidelines according to which bacterial pathogens need to be tested against these products. The required cultures are generally environmental reference ATCC (American type culture collection) strains, which ensure consistency and fair treatment when doing product registration. 

However, the situation in the field, farm, or hospital ward may be very different. The pathogens that are found in these settings may be totally different from the ATCC strains, as they are regularly challenged with disinfectants and antibiotics. 

Work performed by Wanja Swart showed that in just 10 consecutive days of exposure to disinfectants, resistance to commonly used disinfectants can increase 32-fold. So why is this important? Firstly, accurate dilution of disinfectants appears to be a challenge for many, so the likelihood of the products being used correctly is relatively small. Also, some of the products have substantial residual activity on surfaces. This will result in the exposure of bacteria to sub-lethal levels for extended periods of time as well as a build-up of disinfectant – which will in turn result in a further increase in resistance. 

Research outputs so far for 2023 include two publications by Samantha Mc Carlie on bacterial resistance to disinfectants in the accredited peer-reviewed journal, Microorganisms, titled ‘Genomic Islands Identified in Highly Resistant Serratia sp. HRI: A Pathway to Discover New Disinfectant Resistance Elements’ and ‘The Hermetic Effect Observed for Benzalkonium Chloride and Didecyldimethylammonium Chloride in Serratia sp. HRI’. In addition, three book chapters have been published in the book Antimicrobial Resistance and One Health in Africa by Springer Publishers, titled ‘Biosecurity and Disinfectant resistance in a Post-antibiotic era’, ‘The Linkage between Antibiotic and Disinfectant Resistance’, and ‘The Current State of Antimicrobial resistance in Bovine Mastitis in Various African Countries’.

News Archive

Researchers international leaders in satellite tracking in the wildlife environment
2015-05-29

 

Ground-breaking research has attracted international media attention to Francois Deacon, lecturer and researcher in the Department Animal, Wildlife and Grassland Sciences at the UFS, and Prof Nico Smit, from the same department. They are the first researchers in the world to equip giraffes with GPS collars, and to conduct research on this initiative. Recently, they have been joined by Hennie Butler from the Department of Zoology as well as Free State Nature Conservation to further this research.

“Satellite tracking is proving to be extremely valuable in the wildlife environment. The unit is based on a mobile global two-way communication platform, utilising two-way data satellite communication, complete with GPS systems.

“It allows us to track animals day and night, while we monitor their movements remotely from the computer. These systems make possible the efficient control and monitoring of wildlife in all weather conditions and in near-to-real time. We can even communicate with the animals, calling up their positions or changing the tracking schedules.

“The satellite collar allows us to use the extremely accurate data to conduct research with the best technology available. The volume of data received allows us to publish the data in scientific journals and research-related articles.  

“Scientific institutions and the public sector have both shown great interest in satellite tracking, which opens up new ground for scientific research for this university. Data management can be done, using Africa Wildlife Tracking (AWT) equipment where we can access our data personally, store it, and make visual presentations. The AWT system and software architecture provide the researcher with asset tracking, GPS location reports, geo-fencing, highly-detailed custom mapping, history reports and playback, polling on demand, history plotting on maps, and a range of reporting types and functions,” Francois said.

Data can be analysed to determine home range, dispersal, or habitat preference for any specific species.

Francois has been involved in multiple research projects over the last 12 years on wildlife species and domesticated animals, including the collaring of species such as Black-backed Jackal, Caracal, African Wild Dog, Hyena, Lion, Cheetah, Cattle, Kudu, Giraffe, and Black Rhino: “Giraffe definitely being the most challenging of all,” he said.

In 2010, he started working on his PhD, entitled The spatial ecology, habitat preferences and diet selection of giraffe (Giraffa camelopardalis giraffa) in the Kalahari region of South Africa.

 

Since then, his work has resulted not only in more research work (supervising four Masters students) but also in a number of national and international projects. These include work in the:

  • Kalahari region (e.g. Khamab Nature Reserve and Kgalagadi Transfrontier Park)
  • Kuruman region (Collared 18 cattle to identify spatial patterns in relation to the qualities of vegetation and soil-types available. This project took place in collaboration with Born University in Germany)
  • Woodland Hills Wildlife Estate and Kolomella Iron Ore – ecological monitoring
  • A number of Free State nature reserves (e.g. Distribution of herbivores (kudu and giraffe) and predators (camera traps)

Francois is also involved with species breeding programmes and management (giraffe, buffalo, sable, roan, and rhino) in Korrannaberg, Rustenburg, Hertzogville, Douglas, and Bethlehem as well as animal and ecological monitoring in Kolomella and Beesthoek iron ore.

Besides the collaring of giraffes, Francois and his colleagues are involved in national projects, where they collect milk from lactating giraffes and DNA material, blood samples, and ecto/endo parasites from giraffes in Southern Africa.

With international projects, Francois is working to collect DNA material for the classification of the nine sub-species of giraffe in Africa. He is also involved in projects focusing on the spatial ecology and adaptation of giraffe in Uganda (Murchison Falls), and to save the last 30 giraffe in the DRC- Garamba National Park.

This project has attracted a good deal of international interest. In June 2014, a US film crew (freelancing for Discovery Channel) filmed a documentary on Francois’ research (trailer of documentary). Early in 2015, a second crew, filming for National Geographic, also visited Francois to document his work.

 

More information about Francois’ work is available at the GCF website. 

Read Francois Deacon's PhD abstract

Direct enquiries to news@ufs.ac.za.

 

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