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1INTERNATIONAL SCIENTIFIC AND PRACTICAL CONFERENCE "STATUS AND DEVELOPMENT PROSPECTS OF FUNDAMENTAL AND APPLIED MICROBIOLOGY: THE VIEWPOINT OF YOUNG SCIENTISTS" _25-26 SEPTEMBER, 2024_
THE EFFECT OF LACTIC ACID BACTERIA ON THE
CANDIDA GROUP
Sohibnazarova Kh.A., Abduvohidova Y.O., Urmonaliyeva Sh.U., Ermatova X.Y., Reyimbergenova Z.A., Oltiboeva Kh.A., Abdunabiev A.M., Gulomov J.I.
https://doi.org/10.5281/zenodo.13832595
Abstract. Candida vaginitis, primarily caused by Candida albicans (over 85% of cases), remains a widespread global infection with increasing prevalence. While non-albicans Candida species such as Candida glabrata, Candida krusei, Candida tropicalis, Candida stelloidea, and Candida dubliniensis are less frequently associated with vaginal yeast infections, they present unique therapeutic challenges. Additionally, factors like excessive use of vulvovaginal care products can disturb the vaginal environment, heightening the risk of infection. The vaginal microbiome, particularly Lactobacillus species, plays a critical role in maintaining vaginal health, and disruptions can lead to symptomatic VVC. This review seeks to summarize the alterations in the vaginal microflora during VVC infection and highlight the potential of using lactic acid bacteria as probiotics for treating VVC.
Keywords: lactobacillus, C. albicans, antimicrobial activity, vaginal infection.
INTRODUCTION
Vaginal candidiasis is a common global infection, with its prevalence rising significantly in recent years. The primary pathogen is Candida, with Candida albicans being the most frequently identified species. However, other Candida species, including Candida glabrata, Candida krusei, Candida tropicalis, Candida stelloidea, and Candida dubliniensis, are also associated with vaginal yeast infections[1]. Excessive use of vulvovaginal care products such as soaps, bubble baths, douches, and creams can disrupt the vaginal environment, increasing the risk of fungal infections. [2,3].
The vaginal microbiome is essential for maintaining host health and plays a significant role in both health and disease. While Candida species, including C. albicans, are part of the normal mucosal flora in most healthy women, they can overgrow under certain conditions, leading to symptomatic vulvovaginal candidiasis (VVC). Studies suggest that probiotic colonization, particularly by Lactobacillus species, can effectively reduce the risk of VVC and assist in its treatment.
The human vagina hosts a diverse array of microorganisms forming the normal microbiota and mycobiota. Lactobacillus species, including Lactobacillus crispatus, Lactobacillus gasseri, Lactobacillus iners, and Lactobacillus jensenii, are the most frequently isolated from healthy vaginas and play a key role in preventing pathogen invasion by maintaining microbial balance [5]. Disruption of this ecosystem can lead to the overgrowth of pathogens, contributing to complicated infections such as bacterial vaginosis (BV), sexually transmitted infections (STIs), and VVC. Factors such as menstruation, pregnancy, sexual practices, excessive antibiotic use, and vaginal douching can alter the microbial community [6]. Thus, the composition of the vaginal microbiota is crucial for vaginal health. Due to their Generally Recognised as Safe (GRAS) status,
INTERNATIONAL SCIENTIFIC AND PRACTICAL CONFERENCE "STATUS AND DEVELOPMENT PROSPECTS OF FUNDAMENTAL AND APPLIED MICROBIOLOGY: THE VIEWPOINT OF YOUNG SCIENTISTS" _25-26 SEPTEMBER, 2024_
Lactobacillus species are increasingly used as alternatives to conventional antimicrobial treatments for preventing chronic vaginitis and restoring the vaginal ecosystem.
MATERIAL METHODS
Isolation of Vaginal candidiasis (VC) pathogens
Vaginal pathogens were isolated from vaginal cultures of women with clinical VC at Aisha (AIWA) medical center (Tashkent) and Karima hospital (Tashkent), whose diagnosis was confirmed by significant VC. Appropriate vaginal fluid samples were cultured on MHA (Himedia) soft agar (tryptic soy broth with 0.7% agar, BBL, Microbiology System, Md) under aerobic conditions at 37°C for 18-24 hours, and pH values were determined.
Antimicrobial activity of lactobacteria isolated from vaginal sources
The substrate for LAB isolated from vaginal sources placed in MRS broth and cultured at 37 ° C for 48 hours for enrichment. Serial dilutions were prepared from the enriched broth and sown as a continuous lawn on MRS agar, 2 dishes for each dilution. 1 dish from 2 replicates was placed in a thermostat under aerobic cultivation conditions, the second - in an anaerobic jar, where the air was replaced with gaseous nitrogen (under anaerobic conditions). Cultivated at 37 ° C for 48 hours. After cultivation, isolated colonies differing in morphological features were selected from the dishes, then transferred to a dish with MRS agar containing 2-3 drops of an alcohol solution of the bromocresol purple indicator to determine acid formation. The dishes were incubated at 37°C until growth appeared. Isolates that changed the color of the medium from purple to yellow were preliminarily considered to be LAB and used for further studies.
Bacterial identification and susceptibility testing
The identification of bacteria isolated from urine samples were performed by Maldi-TOF. Initially, the vaginal samples are cultured on Mueller Hinton agar (Himedia), Hicrome Candida Differential agar and were incubated at temperature 35-37°C.
RESULTS
Five types of Candida albicans accounted for 20% of vaginal candidiasis (VC) cases, Candida tropicalis for 15%, Candida glabrata for 45%, and Candida krusei for 20%. Lactobacillus strains comprised 1% of the total. When the antimicrobial properties of the isolated vaginal LAB strains were examined, their activity was found to be low overall. However, the results revealed that Lactiplantibacillusplantarum QP-1 exhibited a 33 mm inhibition zone against Candida tropicalis R-53.2. Additionally, Lactobacillus delbrueckii 13.1 and Lacticaseibacillus paracasei 24.3 demonstrated 16 mm of activity against Candida krusei 17.2 c 12 mm (Table-1).
Table 1 Comparison of inhibitory zones (mm) produced by three different vaginal lactic acid bacteria (VLAB) strains against twelve VC pathogens in agar blot analysis
№ VC strains Effect of VLAB strains against VC bacteria Diameter of
inhibition zone (mm)
Lactiplantibacillu Lactobacillus de Lacticaseibacillus
s plantarum QP-1 lbrueckii 13.1 paracasei 24.3
1. Candida glabrata 9.1 0 0 0
2. Candida glabrata 7.1 0 0 0
INTERNATIONAL SCIENTIFIC AND PRACTICAL CONFERENCE "STATUS AND DEVELOPMENT PROSPECTS OF FUNDAMENTAL AND APPLIED MICROBIOLOGY: THE VIEWPOINT OF YOUNG SCIENTISTS" 25-26 SEPTEMBER, 2024
3. Candida glabrata R-48.1 0 0 0
4. Candida albicans R-34.1 0 0 0
5. Candida albicans R-13 0 0 0
6. Candida albicans R-41 0 0 0
7. Candida krusei R-27.1 0 0 0
8. Candida krusei 25 c 0 0 0
9. Candida krusei 17.2 c 0 12 ±0.5 16 ±0.5
10. Candida tropicalis R-28 0 0 0
11. Candida tropicalis R-29 0 0 0
12. Candida tropicalis R-53.2 33±0.5 0 0
P < 0.05 was considered statistically significant.
Conclusion
The findings demonstrate that the antimicrobial activity of the isolated VLAB (vaginal lactic acid bacteria) strains was insufficient against Candida species, showing minimal inhibitory effects. Given the lack of significant antimicrobial action, these VLAB strains are not suitable for use in further research or applications as active strains. Their inability to effectively target Candida suggests that alternative strains or approaches will be necessary for future studies focused on antifungal properties and the development of effective treatments.
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