BACKGROUND AND OBJECTIVE Polymicrobial infections are acute and chronic diseases that are caused by a combination of fungi, bacteria, viruses and parasites. In this interaction, one microorganism predisposes conditions for other microorganism to enhance its virulence factors application. Vulvovaginal candidiasis (VVC) is an infection of the female genital tract that is mostly caused by Candida albicans. In women, it is possible to cause urinary-vaginal cross-infections due to the short urethra. In this research, we survey the effect of some urinary infection bacteria including Escherichia coli, Klebsiella pneumoniae, and Streptococcus agalactiae on some Candida albicans virulence factor including yeast-hyphae transition and biofilm formation. MATERIALS AND METHODS: Samples of urine and vaginal swap from the infected woman were inoculated on Tryptic Soy Agar (TSA)/MacConkey Agar (MAC) and Sabouraud Dextrose Agar (SDA) to isolate bacterial and fungal strains, respectively. Strains were identified based on the standard biochemical tests. The fungal and bacterial strains were grown overnight in YPD broth media (Yeast extract Peptone Dextrose) at 37 ℃. In vitro formation of mixed biofilm was performed by adding 1000 ml of each fungi and bacteria suspension into the wells of 12-well polystyrene plates. The plates were incubated for 24 h at 37 ℃. Bright field microscopy was used to examine the hypha production. The adhered biofilm was manually scraped off and 100 mL aliquots of the desired dilution were seeded on plates containing YPD agar and incubated for 48 h at 37 ℃. After incubation, the fungus colony forming units per milliliter (CFU mL-1) were determined for the single and dual biofilms. RESULTS AND DISCUSSION: We isolated three uropathogenic strains i.e., Escherichia coli, Klebsiella pneumoniae, and Streptococcus agalactiae and one fungal strain; C. albicans. The yeast to hyphae transition of C. albicans in single and dual species biofilms were compared and revealed that more hyphae were formed in dual culture and the most hyphae were observed in the presence of E. coli. More biofilms were also formed in the dual cultres and were calculated as (CFU Ml-1) …, …., and, …, in the dual culture with E.coli, K. pneumoniae, and S. agalactia, respectively. While …. was observed in the single culture. This study demonstrated the effects uropathogenic bacteria to promote fungi virulence factors, which suggest polymicrobial interaction should be considered during treatment of fungal infections.

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