Candidemia is one of the nosocomial systemic infections with a high mortality rate, especially in neonates and pediatric patients (16). The prevalence of candidemia in published reports was varied (17–19). In our study, the incidence of candidemia was 3.4% among hospitalized patients with positive blood cultures. Agree with our study, this rate was reported to be 3.5% in Motta et al, from Brazil (20). However, the incidence of candidemia in published reports from the US and Europe was lower than from our study (18, 19). Amphotericin B was the most widely used antifungal drug. However, 40.7% of our patients were not treated with antifungal drugs. This result disagrees with other studies that reported fluconazole was the most antifungal drug received in candidemia patients (21, 22). The low mortality rate (14.8%) were obtained in our study was mostly lower than other reported in Iran (28–47%) (21, 22). It seems that this difference may due to different conditions of candidemia patients such as underlying disease, antifungal therapy, the type of Candida species, and the length of hospitalization. In the present study, C. albicans was the only cause of mortality in candidemia patients. However, C. tropicalis was reported for the high mortality rates in another study (23, 24).
This study showed that C. albicans was the most frequent species causing Candidemia (%78.5). These results are in agreement with the other studies conducted in Iran, such as Razzaghi et al. and Sadrossadati et al,. who reported that C. albicans was the most common (25, 26). The present study is also compatible with the other studies reported from different regions of the world (27, 28). However, in recent years, the emergence of infections caused by non- albicans species increased as the common etiology of candidemia (29, 30). In studies such as those performed by Chander et al. in India (31), and Ghahri et al. in Iran (29), C. tropicalis (40.8%) and C. parapsilosis (34.4%) were found to be the most frequent cause of candidemia, respectively. The reason for the emergence of non-albicans species can be associated with some underlying conditions which were different for each species (25). In our study, the second most frequent Candida species were C. parapsilosis. Similar to our results Sadrossadati et al. (26) and Kooshki et al. (32) revealed that C. parapsilosis was the second most prevalent isolated species. However, Arastefar et al, showed that C. glabrata was the second agent of candidemia in Shiraz (22). This contrast may be due to the difference age groups of patients.
In our study, the MIC range for FLZ was evaluated between 0.0625 and 32 𝜇g/ml for the 27 Candida strains. Besides, resistance to fluconazole was detected in 5.6% of C. albicans strains, however, all non-albicans strains were sensitive to this drug. Similarly, Arastehfar et al., were reported that 4.42% of Candida strains isolated to blood culture resistant to fluconazole (22). Although initially, it seems that triazoles are highly efficient, but overusing them is associated with azole resistance in Candida species (33). For instance, Kumar et al. (34) detected 19% resistance in Candida strains in India, while Mohammed Khairat et al. (35) demonstrated 38.9% of C. albicans isolates resistant to fluconazole. It should be noted that the history of treatment with antifungal drugs and underlying disease of patients can be involved in varying degrees of resistance.
Even though amphotericin B is one of the most toxic antifungal drugs in clinical use, it is still considered a standard and inexpensive treatment (25, 36). In this study, 100% C. albicans strains were wild-type to amphotericin B. This result similar to Arastehfar et al,. shows that all candidemia isolates were wild-type against amphotericin B (22). In international studies such as Motta et al, also, amphotericin B resistance among Candida bloodstream isolates was rare (20). Therefore, it seems that amphotericin B can be a choice of therapeutic agent for patients with candidemia.
Echinocandins are generally effective against candidemia and it has been shown that their therapeutic use is in line with low mortality (1, 37). Among echinocandin antifungal agents, caspofungin is more used in Iran (38). This drug has been demonstrated as the most effective against resistance Candida species to other antifungals (25). In this study, antifungal susceptibility tests indicate that caspofungin was the most efficient drug against Candida species (MIC ≤ 1 𝜇g/mL). In the other studies carried out in Iran, different rates of resistance have been reported. The susceptibility profile of caspofungin in our study was similar to that reported in Iran and other countries (20, 25). In some studies, resistance to this drug has been observed in non-albicans species, such as C. parapsilosis, and C. krusei (39, 40).