Medical staff at the University of the Free State (UFS) and the National Health Laboratory Service (NHLS) at the Universitas Academic Hospital have identified the first case of S. oblongispora mucormycosis in sub-Saharan Africa and among HIV-positive patients.
This discovery was made when a 32-year-old male patient was admitted to the Universitas Academic Hospital with right-sided facial swelling. The patient was HIV-positive, with a CD4 count of 50 cells/µl, and on antiretroviral therapy (ART), together with trimethoprim–sulfamethoxazole (TMX) prophylaxis. Additionally, he had hypertension for which he was also receiving treatment. The patient’s facial swelling rapidly progressed, with extension of redness and swelling observed daily.
Four days after admission, he underwent computerised tomography (CT) scan, and tissue biopsies were collected. The patient died three days later.
A significant discovery
Dr Bonita van der Westhuizen, Senior lecturer and Pathologist in the UFS Department of Medical Microbiology, who identified this rare fungus said this discovery is significant because it highlights 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.
Dr Van der Westhuizen says though it is unclear where the deceased 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 earlier this month (August) in the Journal Case Reports in Pathology.
Progresses rapidly
“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,” she says.
These fungi, Dr Van der Westhuizen explains, can resist being killed by immune cells, allowing them to establish infection. Some Mucorales fungi can produce toxins that disrupt blood vessels, further aiding the spread of the infection. Additionally, 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,” says Dr Van der Westhuizen.
It is important to note, she continues, 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.
Fungal diagnostics is complex
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 of a combination of different testing platforms was used to identify this infection. Says Dr Van der Westhuizen: “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.
“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.”
There is a possibility that these infections had been missed before and even still today. 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, says Dr Van der Westhuizen, who will now also embark 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.