Hospital distribution, seasonality, time trends and antifungal susceptibility profiles of all Aspergillus species isolated from clinical samples from 2015 to 2022 in a tertiary care hospital

Background Aspergillus species cause a variety of serious clinical conditions with increasing trend in antifungal resistance.

The present study aimed at evaluating hospital epidemiology and antifungal susceptibility of all isolates recorded in our clinical database since its implementation.

Methods Data on date of isolation, biological samples, patients’ age and sex, clinical settings, and antifungal susceptibility tests for all Aspergillus spp. isolated from 2015 to 2022 were extracted from the clinical database.

Score test for trend of odds, non-parametric Mann Kendall trend test and logistic regression analysis were used to analyze prevalence, incidence, and seasonality of Aspergillus spp. isolates.

Results A total of 1126 Aspergillus spp. isolates were evaluated.

A. fumigatus was the most prevalent (44.1%) followed by A. niger (22.3%), A. flavus (17.7%) and A. terreus (10.6%).

A. niger prevalence increased over time in intensive care units ( p -trend = 0.0051).

Overall, 16 (1.5%) were not susceptible to one azole compound, and 108 (10.9%) to amphotericin B, with A. niger showing the highest percentage (21.9%).

The risk of detecting A. fumigatus was higher in June, (OR = 2.14, 95% CI [1.16; 3.98] p  = 0.016) and reduced during September (OR = 0.48, 95% CI [0.27; 0.87] p  = 0.015) and October as compared to January (OR = 0.39, 95% CI [0.21; 0.70] p  = 0.002.

A. niger showed a reduced risk of isolation from all clinical samples in the month of June as compared to January (OR = 0.34, 95% CI [0.14; 0.79] p  = 0.012).

Seasonal trend for A. flavus showed a higher risk of detection in September (OR = 2.7, 95% CI [1.18; 6.18] p  = 0.019), October (OR = 2.32, 95% CI [1.01; 5.35] p  = 0.048) and November (OR = 2.42, 95% CI [1.01; 5.79] p  = 0.047) as compared to January.

Conclusions This is the first study to analyze, at once, data regarding prevalence, time trends, seasonality, species distribution and antifungal susceptibility profiles of all Aspergillus spp. isolates over a 8-year period in a tertiary care center.

Surprisingly no increase in azole resistance was observed over time.