UFS pathologist uncovers rare and lethal fungus in HIV-positive patient

The first case of a rare and deadly fungus in sub-Saharan Africa has been identified by medical staff from the University of the Free State (UFS) and National Health Laboratory Service (NHLS) at the Universitas Academic Hospital. 

The staff identified the first case of S. oblongispora mucormycosis in sub-Saharan Africa and among HIV-positive patients.

The discovery was made when a 32-year-old man was admitted to the Universitas Academic Hospital with right-sided facial swelling. 

The patient was HIV positive, had a low CD4 count and was on antiretroviral therapy (ART), together with trimethoprim–sulfamethoxazole (TMX) prophylaxis. He also had hypertension, for which he was receiving treatment. The patient’s facial swelling rapidly progressed, with extension of redness and swelling observed daily.

According to medical staff, four days after admission, the patient underwent a computerised tomography (CT) scan, and tissue biopsies were collected. The patient died three days later. 

Senior lecturer and pathologist at the UFS Department of Medical Microbiology, Dr Bonita van der Westhuizen, who identified the rare fungus, said the discovery was significant because it highlighted the presence of this fungal pathogen in a region where it may have been previously unrecognised or underreported. 

“It now raises awareness about the diversity of fungal infections affecting immunocompromised populations and underscores the need for improved diagnostics, surveillance, and treatment strategies in the region,” she said

Dr Van der Westhuizen said that though it is unclear where the deceased patient might have picked up this infection, moulds are ubiquitous in the environment. Patients usually get infected by inhalation of spores or traumatic implantation. Together with colleagues Drs Liska Budding and Christie Esterhuysen, both from the UFS Department of Anatomical Pathology and the NHLS, and Prof Samantha Potgieter, infectious disease expert in the UFS Department of Internal Medicine, Dr Van der Westhuizen published the case in August in the Journal Case Reports in Pathology.

“Mucormycosis, which is caused by fungi in the order Mucorales, progresses rapidly due to a combination of factors related to the fungus, the host, and external influences. Mucorales fungi are known for their fast growth and ability to invade blood vessels. This allows the infection to spread quickly through the body, potentially reaching vital organs,” Dr Van der Westhuizen said. 

She said these fungi can resist being killed by immune cells, allowing them to establish an infection. 

Some Mucorales fungi can produce toxins that disrupt blood vessels, further aiding the spread of the infection, and certain host conditions weaken the body's defences, allowing the infection to spread quickly.

“External factors that may play a role are traumatic injuries, endothelial damage and rarely hospital-acquired infections. In essence, the aggressive nature of Mucorales fungi, combined with weakened host defences and external factors, creates a perfect storm for rapid disease progression in susceptible individuals.

“The Mucorales as a group normally infects patients with underlying risk factors including factors including diabetes mellitus, malignancies, transplant recipients, and current or past COVID-19 infection; however, this organism in particular, usually infects immunocompetent patients after traumatic inoculation,” Dr Van der Westhuizen said.

She said it was important to note that that all available data comes from research done in tropical regions. There is no data on this organism in sub-Saharan Africa, which means it is still unknown what role this pathogen plays in our local patient population. The diagnostic complexities and rapid disease progression may contribute to the paucity of data in developing countries.

“This infection can be treated with available antifungal agents, as well as surgical debridement of infected tissue. The challenge, however, is the rapid disease onset and progression to death. There is only a tiny window to help the patient. That is why clinical suspicion is so important, as immediate aggressive surgical debridement with antifungal agents is the only way to improve patient outcome. Unfortunately, this infection still has a high mortality rate, despite therapy,” Dr Van der Westhuizen said.

An invasive fungal infection (IFI) was not suspected in this patient, and he received neither antifungal therapy nor surgical interventions. His cause of death, likely the IFI, was only identified after he passed away, and because a combination of different testing platforms was used to identify this infection. 

“This is unfortunately the case with mould infections as most readily available diagnostic methods lack sensitivity, and these pathogens take long to grow in the laboratory. Fungal diagnostics is a specialised field that requires expertise. However, if clinicians are aware of these infections and they have an increased index of suspicion, appropriate therapy can be initiated even before the results are available,” Dr Van der Westhuizen said. 

“If clinicians suspect this type of infection early and they involve the infectious diseases physicians, microbiology and histopathology for support and advice, they will be guided to collect the most appropriate samples to ensure that an accurate diagnosis is made,” she said. 

There is a possibility that these infections had been missed before and even still today. 

Dr Van der Westhuizen said fungal diagnostics is a very complex field for various reasons. There is no highly sensitive, stand-alone test to make a rapid diagnosis available. As newer methods are being developed and molecular diagnostics are advancing, fungal diagnostics are improving. A combination of testing platforms is still required to improve the sensitivity of diagnosing these infections.

Her hope for this research, which will now also embark on further research into local fungal species for her PhD, their epidemiology, diagnostics, and their impact on vulnerable populations, ultimately contributing to better clinical care and health outcomes, is to advance understanding and awareness of Invasive mould infections specifically S. oblongispora, in sub-Saharan Africa and among HIV patients. 

She aims to improve early diagnosis, treatment strategies, and clinical outcomes, as well as to highlight the importance of monitoring fungal infections in immunocompromised populations. Additionally, her goal includes encouraging further research and collaboration in this area to better address fungal infections in the region.

robin.francke@iol.co.za

IOL