Influence of Candida albicans biofilms on the resistance of Salmonella typhi to antibiotics

In many countries around the world, Candida albicans - Salmonella typhi co-infection would represent a real health problem according to the potential interactions that exist between both pathogens. The aim of this work was to study the impact of C. albicans on the resistance of S. typhi to antibiotics and to determine the influence of fungal biofilms on its growth. Reactivated clinical isolates of S. typhi (n = 5) and C. albicans (n = 5) were co-cultured on specific media containing or free of MgCl2. The colonies obtained were analysed by microscopy and an antibiogram was performed from it. The analysis indicated that in case of simultaneous growth of S. typhi and C. albicans, there is improvement in fungal biofilm formation. But when S. typhi infection is posterior to that of C. albicans, fungal biofilms stimulated in vitro are disorganized. Moreover, the sensibility of S. typhi to antibiotherapy in-vitro appeared to decrease in the presence of C. albicans , by approximately 100% with ofloxacin, amoxicillin, doxycycline, ciprofloxacin and ceftriaxone, 87.55% with cefoxitime and 80% with colistin. Altogether, the results of the present study suggest that the co-culture of both pathogens improves the infectious capacity and resistance of S. typhi to antibiotherapy through fungal biofilm.