Enemies and brothers in arms:Candida albicansand gram-positive bacteria

Abstract

Candida albicans is an important human opportunistic fungal pathogen which is frequently found as part of the normal human microbiota. It is well accepted that the fungus interacts with other components of the resident microbiota and that this impacts the commensal or pathogenic outcome of C. albicans colonization. Different types of interactions, including synergism or antagonism, contribute to a complex balance between the multitude of different species. Mixed biofilms of C. albicans and streptococci are a well-studied example of a mutualistic interaction often potentiating the virulence of the individual members. In contrast, other bacteria like lactobacilli are known to antagonize C. albicans, and research has just started elucidating the mechanisms behind these interactions. This scenario is even more complicated by a third player, the host. This review focuses on interactions between C. albicans and gram-positive bacteria whose investigation will without doubt ultimately help understanding C. albicans infections.

Development and regulation of single- and multi-species Candida albicans biofilms

“…Some relationships between C. albicans and bacterial species are synergistic, providing protection to one or both species in the context of dual-species biofilms 133 (FIG. 4c).…”

“…Interspecies interactions are not limited to direct physical contact; some rely on the secretion and diffusion of signalling molecules and others on local environmental changes (for example, alterations in pH, oxygen or carbon dioxide levels) to influence the behaviour of one species towards the other 32,133 (FIG. 4d,e).…”

“…Other interactions between C. albicans and bacterial partners can also affect virulence during an infection 133 . For example, when C. albicans and specific oral Streptococcus species, such as Streptococcus oralis , S. sanguinis , or S. gordonii , were placed in a flow-cell-based oral-cavity infection model, the two species demonstrated a cooperative interaction that increased tissue invasion and colonization compared with monotypic infections 148 .…”

Antimicrobial Compounds Produced by Vaginal Lactobacillus crispatus Are Able to Strongly Inhibit Candida albicans Growth, Hyphal Formation and Regulate Virulence-related Gene Expressions

“…It is well accepted that the interactions between C. albicans and other components of the resident bacteria, particularly Lactobacillus spp., play important roles in determining the commensal or pathogenic outcome of this fungus (Förster et al, 2016). Lactobacilli are predominant microorganisms in the normal vaginal microbiota, where the most frequently isolated species are L. crispatus , L. gasseri , and L. jensenii (Petrova et al, 2015).…”

Phenotypic and genotypic characteristics of Candida albicans isolates from bloodstream and mucosal infections

“…2,4,7 C. albicans is a human commensal, with a natural habitat in the gastro-intestinal (GI) tract, skin and female genital organ. 8 Although it is believed that the host's immune status and other human defence systems are the defining factors whether this fungus will be either a benign coloniser, a causative agent of a superficial or invasive infection, [9][10][11] the interaction of this fungus with the host is more complex, as elegantly described in a recent review of Hofs et al [12]. The interplay between the expression of the fungal virulence features and the host's response may play a role, contributing to the end result.…”