Isolation of Cryptococcus Species from Sputum of Patients with Presumptive Pulmonary Tuberculosis Attending a Referral Hospital in Cross River State, Nigeria

Introduction: The differential diagnosis of pulmonary tuberculosis (TB) and fungal infections is important in influencing treatment strategies and enhancing therapeutic success. Therefore, this study aimed to investigate the prevalence of Cryptococcus species among presumptive tuberculosis patients in a referral hospital in Nigeria. Methods: This cross-sectional, hospital-based study was carried out between October ۲۰۲۴ and January ۲۰۲۵. A total of ۱۷۴ sputum samples were tested for the presence of Mycobacterium tuberculosis using Ziehl-Neelsen staining and the molecular GeneXpert MTB/RIF assay; Cryptococcus species were isolated by culture on Sabouraud Dextrose Agar (SDA) and presumptively identified as encapsulated yeasts using India ink staining. Results: None of the samples (۰%) obtained from presumptive tuberculosis patients were positive for M. tuberculosis, highlighting the importance of investigating other pathogens, such as Cryptococcus species, in patients presenting with TB-like symptoms. Cryptococcus species were isolated from ۲۱ of ۱۷۴ patients, giving an overall prevalence of ۱۲.۱%. A significant gender disparity was observed, with females showing a much higher prevalence (۳۵.۲%) compared with males (۱.۷%). Age was not significantly associated with infection status, although individuals aged ۵۰–۵۹ years had the highest age-specific prevalence, with ۴ out of ۲۰ patients (۲۰.۰%) testing positive. Statistical analysis confirmed the significant gender difference (χ² = ۳۹.۴۲۶, P < ۰.۰۰۱), while the association with age was not statistically significant (Fisher–Freeman–Halton exact test statistic = ۷.۶۸۱, P = ۰.۱۹۹). No Cryptococcus isolates were recovered from participants aged ۱–۹ years, ۴۰–۴۹ years, and ≥ ۶۰ years. Conclusion: The moderate prevalence of Cryptococcus species observed in this study suggests their potential as a lower respiratory tract pathogen in presumptive tuberculosis patients. The results of this study show the need to integrate fungal screening into routine diagnostic protocols for tuberculosis, especially where fungi such as Cryptococcus species are often neglected.

کلیدواژه ها:

Cryptococcus species ، Presumptive ، Pulmonary ، Tuberculosis ، Prevalence ، Cross River State ، Nigeria