[Isolated yeast species in urine samples in a Spanish regional hospital]

Urinary Microbiome: Yin and Yang of the Urinary Tract

The application of next generation sequencing techniques has allowed the characterization of the urinary tract microbiome and has led to the rejection of the pre-established concept of sterility in the urinary bladder. Not only have microbial communities in the urinary tract been implicated in the maintenance of health but alterations in their composition have also been associated with different urinary pathologies, such as urinary tract infections (UTI). Therefore, the study of the urinary microbiome in healthy individuals, as well as its involvement in disease through the proliferation of opportunistic pathogens, could open a potential field of study, leading to new insights into prevention, diagnosis and treatment strategies for urinary pathologies. In this review we present an overview of the current state of knowledge about the urinary microbiome in health and disease, as well as its involvement in the development of new therapeutic strategies.

Antibacterial and Antifungal Activity of Propyl-Propane-Thiosulfinate and Propyl-Propane-Thiosulfonate, Two Organosulfur Compounds from Allium cepa: In Vitro Antimicrobial Effect via the Gas Phase

Propyl-propane thiosulfinate (PTS) and propyl-propane thiosulfonate (PTSO) are two volatile compounds derived from Allium cepa with a widely documented antimicrobial activity. The aim of this study was to evaluate their anti-candidiasis activity and the ability of its gaseous phase to inhibit bacterial and yeast growth in vitro. The minimum inhibitory concentration of various antifungal products (including PTS and PTSO) was determined versus 203 clinical isolates of Candida spp. through broth microdilution assay. Additionally, the antimicrobial activity through aerial diffusion of PTS and PTSO was evaluated over the growth of a collection of bacteria and yeasts cultivated in agar plates. All yeasts were susceptible to the antifungals tested, except C. glabrata and C. krusei, that showed azole resistance. PTSO (MIC₅₀ and MIC₉₀ ranged from 4 to 16 mg/L and 8 to 32 mg/L, respectively) was significantly more active against yeasts than PTS (MIC₅₀ and MIC₉₀ ranged from 16 to 64 mg/L and 32 to 64 mg/L). Values were higher than those obtained for antifungal drugs. Gaseous phases of PTS and PTSO generated growth inhibition zones whose diameters were directly related to the substances concentration and inversely related to the microbial inoculum. The quantification of PTS and PTSO levels reached in the growth media through aerial diffusion displayed a concentration gradient from the central zone to the periphery. Only P. aeruginosa ATCC 27853 showed resistance, while yeasts (C. albicans ATCC 200955 and C. krusei ATCC 6258) presented the higher susceptibility to both compounds. These results suggest that PTS and PTSO display antibacterial and anti-candidiasis activity in vitro through aerial diffusion, having potential use in human therapy.

[Inpatient candiduria: etiology, susceptibility to antifungal drugs and risk factors]

OBJECTIVE

Candida could become the second most frequent cause of nosocomial urinary tract infection. Although Candida albicans is the most important species, others have arisen as emerging pathogens. The aim of this study was to analyze the presence of candiduria in inpatients.

METHODS

We performed a retrospective study of Candida isolates from adult inpatient urocultures over five years, gathering and tabulating data on: the species; susceptibility to fluconazole, amphotericin B, and voriconazole (Vitek2, BioMerieux); presence of catheter; hospital department of origin; and patient age and sex.

RESULTS

We detected 289 yeast episodes, observing an annual increase: 134 (46.4%) were non-C. albicans yeasts, with 57 (19.7%) being Candida glabrata, 37 (12.8%) Candida tropicalis, 25 (8.6%) Candida parapsilosis, and 10 (3.5%) Candida lusitaniae. Most isolates derived from catheterized (240, 83.0%) and Internal Medicine Department (118, 40.8%) patients, observing an annual increase; 152 (52.6%) isolates were from males, and the mean age was >65 years. Susceptibility to antifungals was >85%.

CONCLUSIONS

Inpatient urocultures should include data on the presence of Candida, which is more prevalent in Internal Medicine Department inpatients, in those with urinary catheter, and in over 65-year-olds. Almost half of the isolates were non-C. albicans yeasts, and we recommend complete identification of the species involved.