Prevalence and antifungal susceptibility of Candida albicans and its related species Candida dubliniensis and Candida africana isolated from vulvovaginal samples in a hospital of Argentina

Abstract

Candida africana taxonomical status is controversial. It was proposed as a separate species within the Candida albicans species complex; however, phylogenetic analyses suggested that it is an unusual variety of C. albicans. The prevalence of C. albicans-related species (Candida dubliniensis and C. africana) as vulvovaginal pathogens is not known in Argentina. Moreover, data on antifungal susceptibility of isolates causing vulvovaginal candidiasis is scarce. The aims of this study were to establish the prevalence of C. dubliniensis and C. africana in vaginal samples and to evaluate the antifungal susceptibilities of vaginal C. albicans species complex strains. We used a molecular-based method coupled with a new pooled DNA extraction methodology to differentiate C. dubliniensis and C. africana in a collection of 287 strains originally identified as C. albicans isolated from an Argentinian hospital during 2013. Antifungal susceptibilities to fluconazole, clotrimazole, itraconazole, voriconazole, nystatin, amphotericin B and terbinafine were evaluated by using the CLSI M27-A3 and M27-S4 documents. Of the 287 isolates, 4 C. dubliniensis and one C. africana strains (1.39% and 0.35% prevalence, respectively) were identified. This is the first description of C. africana in Argentina and its identification was confirmed by sequencing the ITS2 region and the hwp1 gene. C. dubliniensis and C. africana strains showed very low MIC values for all the tested antifungals. Fluconazole-reduced-susceptibility and azole cross-resistance were observed in 3.55% and 1.41% of the C. albicans isolates, respectively. These results demonstrate that antifungal resistance is still a rare phenomenon in this kind of isolates.

Hyphal wall protein 1 gene: A potential marker for the identification of different Candida species and phylogenetic analysis

“…Consistent with the last phylogenetic evidence [ 17 , 39 ], we found that C. dubliniensis and C. africana fell into C. albicans complex as shown for ITS1-5.8S-ITS2 gene in Figure 3 . The phylogenetic tree of HWP1 gene indicated that the C. dubliniensis isolates formed a monophyletic group nested within the clade of C. albicans .…”

<em>Candida africana</em> and <em>Candida dubliniensis</em> as causes of pediatric candiduria: A study using <em>HWP1</em> gene size polymorphism

“…This result corroborates the findings reported in Iran-where the frequency C. africana (3%) and C. dubliniensis (0%) was reported among 100 vaginal isolates of C. albicans species complex [10] –and a multicenter study that reported a higher frequency of C. africana (7.2%) than C. dubliniensis (2.9%), among Candida isolates recovered from 498 clinical specimens originated from various patient groups [26] . However, the higher isolation rate of C. dubliniensis over C. africana is being reported from other studies [9] , [13] , [19] , [20] . Whereas C. dubliniensis is being predominantly recovered from oral and oropharyngeal lesions of HIV/AIDS patients, isolates were shown to be recovered from other patients suffering from cancer [14] , cystic fibrosis [27] , genital and respiratory tracts infections [9] – [13] , [19] , [20] , [28] , and from a gastric fluid sample [26] .…”

“…However, the higher isolation rate of C. dubliniensis over C. africana is being reported from other studies [9] , [13] , [19] , [20] . Whereas C. dubliniensis is being predominantly recovered from oral and oropharyngeal lesions of HIV/AIDS patients, isolates were shown to be recovered from other patients suffering from cancer [14] , cystic fibrosis [27] , genital and respiratory tracts infections [9] – [13] , [19] , [20] , [28] , and from a gastric fluid sample [26] . The reason(s) for the disparate frequencies of isolation might be linked to factors such as the difference in the quality of sampling, the anatomic sites, the nature of the clinical sample, the underlying disease entities, racial or genotypic differences, and the immune status of the individuals involved.…”

“…The ‘ C. albicans complex’ is a group of opportunistic fungal pathogens responsible for more than 50% of candidiasis [1] , [7] . Species of this group are more often involved in oral and vaginal human infections [9] , [10] , [12] , [19] . However, infections from other body sites such as respiratory tracts, urinary tracts, wounds, and skin, have been reported [12] , [13] , [20] , [21] .…”

Whole Genome-Based Amplified Fragment Length Polymorphism Analysis Reveals Genetic Diversity in Candida africana

“…However, currently C. africana is known as a biovariant of C. albicans with an exceptional capacity to colonize human genitalia and cause mainly vaginal infections (Romeo and Criseo, 2011; Romeo et al, 2013). Its distribution appears to be worldwide, with cases of infection reported from China (Shan et al, 2014; Hu et al, 2015), Japan (Odds et al, 2007), South Korea (Song et al, 2014), Colombia (Rodríguez-Leguizamón et al, 2015), Argentina (Theill et al, 2016), Chile (Odds et al, 2007), India (Sharma et al, 2014), Iran (Yazdanparast et al, 2015), Africa (Tietz et al, 2001; Dieng et al, 2012; Nnadi et al, 2012; Ngouana et al, 2015), USA (Romeo et al, 2013), and Europe (Alonso-Vargas et al, 2008; Romeo and Criseo, 2009; Borman et al, 2013). However, despite the efforts made so far, it is rather difficult to discriminate C. africana from C. albicans in clinical diagnostic laboratories and therefore its epidemiology is still unclear and needs more investigation (Romeo et al, 2013).…”