Invasive Factors Recognition in Aspergillus Section Nigri Isolates from Patient and Environmental Samples in the Centre Region, Cameroon

Background: Aspergillus section Nigri species are invasive opportunistic pathogens, seen in individuals with various immune disorders. The invasive capacity involves the production of varieties of enzymes such as lipases, phospholipase, proteases and hyaluronidase. The determination of proteinase, phospholipase, esterase and biofilm production in patient and environmental isolates approve the pathogenic strength of the species.

Aims: To evaluate the invasive capacity of Aspergillus section Nigri isolates from patients and environmental samples.

Methods: Our study is cross sectional and experimental, performed at the outpatient clinic of the otorhinolaryngology department of Central and University teaching hospital during a period of 12 months from March 2018 to February 2019. To determine the invasive capacity of Aspergillus section Nigri species, 400 samples were evaluated in the study (that is; 250 from patients and 150 samples from environment). Patient samples and hospital environment samples were evaluated by standard phenotypic methods for detecting of Proteinase, phospolipase, esterase and biofilm. The variables were statistically analyzed using Chi-square test of independent and SPSS (Version 16.0).

Results: The isolates recovered from the patient sample shows maximum invasive capacity as compared to the environmental isolates, that is for 44 isolates; 42 isolates showed proteinase activity and biofilm production, followed by phospholipase activity 36, and then esterase 32.The isolates recovered from the hospital environment also showed the production of the various invasive factors, that is for 16 isolates; 15 isolates showed biofilm production, followed by proteinase activity 6, phospholipase 5 and esterase 4.The disparities of the invasive capacity in patient and environment isolates virulence were statistically significant for proteinase, phospholipase and esterase ( that is; p-value <0.05). Majority the isolates recovered from patients and the environment were potential producers of biofilm.

Conclusion: The isolates recovered from patients sample showed high invasive capacity as compare to the isolates recovered from the environment. This highlights the implications of phospholipase enzyme, proteinase enzyme, esterase enzyme and biofilm used by Aspergillus section Nigri isolates as means of survival in the host system.