The effect of oral bacteria on Candida albicans germ‐tube formationNote

Abstract: A total of eight bacterial isolates belonging to six species, and a select group of 12 oral Candida albicans isolates, were used to study the effect of bacteria on germ‐tube formation. Briefly, each bacterial suspension (10 5–6 cells/ml) was mixed with a C. albicans suspension (10 7 cells/ml) and incubated at 37 °C for 90 min with bovine serum, and the percentage germ‐tube‐positive Candida cells was quantified using a haemocytometer, under light microscopy. In general, out of eight bacteria, Streptococcus sanguis SK21A , Streptococcus salivarius SK56 , Escherichia coli ATCC 25922 , and S. salivarius OBU3 suppressed germ‐tube formation to varying degrees, with different C. albicans isolates. Porphyromonas gingivalis Pg 50 , Lactobacillus casei ATCC 7469 and Prevotella intermedia OBU4 elicited significant enhancement of germ‐tube formation, whereas S. sanguis OBU 2 had no effect. E. coli ATCC 25922 was the only organism to show statistically significant suppression of germ‐tube formation (p=0.0312). A significant increase in the germ tube production of C. albicans isolated from HIV‐infected compared with HIV‐free individuals was also noted. The current results tend to suggest that commensal and transient oral bacterial populations may selectively influence the differential expression of germ‐tube‐forming ability of C. albicans isolates.