Spectrum of Filamentous Fungi from Sputum of Tuberculosis Relapse and Retreatment Patients in Tuberculosis Reference Facilities

Abstract

Background: Fungal infections represent a significant cause of morbidity and mortality among immunocompromised individuals. Pulmonary fungal infection may be missed or misdiagnosed as tuberculosis (TB) hence complicating management of these patients. The current study reports the spectrum of filamentous fungi isolated from sputum of TB relapse and retreatment cases at selected reference facilities in Kenya. Methods: A total of 340 sputum samples collected during the period of June 2018 to June 2019 were subjected to mycological investigations. The samples were mucolysed and inoculated on sabourauds dextrose agar (SDA) and incubated at 30°C for 7 days and checked daily for fungal growth. Moulds were identified by macroscopic and microscopic morphological features and the species were confirmed by sequencing. Results: The diversity of fungi out of the 340 sputum samples analyzed was as follows; 16% (n = 53) were positive for moulds with Aspergillus species being the predominant constituting 68 % (n = 36). Among the Aspergilli, A. flavus and A. niger were the most frequently isolated adding up to 23%, (n = 12) and 15% (n = 8) respectively. Additionally, Paecillomyces variotii (9%, n = 5), Scedosporium aspiospermum (6%, n = 3), Mucor racemosus (8%, n = 4) and Penicillium spp. (9%, n = 5) were also recovered. Conclusion: The isolated fungi represented potential respiratory pathogens that could be responsible for persistent TB like symptoms despite treatment that could be misdiagnosed as relapse requiring treatment. Fungal investigation of all presumptive TB relapse cases should be advocated before treatment. This will reduce unnecessary retreatment, delayed antifungal intervention and unwarranted morbidity and mortality associated with misdiagnosis.