Effects of changes in culture conditions on the virulence and antifungal susceptibility of dairy cow mastitis fungal isolates

Abstract Background: In recent years, the number of incidences of dairy cow mastitis caused by non-albicans Candida (NAC) have increased owing to the virulence factors, including cell surface hydrophobicity (CSH) and phospholipase activity, of the causative agents, namely, Candida krusei and Candida parasitica. Temperature and pH changes in the cow's udder after fungal infection and unreasonable medication can affect the antifungal susceptibility of Candida spp. and their expression of virulence factors. Methods: In this study, the effects of different temperatures and pH on the virulence of NAC strains were tested, and the in vitro susceptibility of the fungal strains to Cu2+ and antibacterial agents were examined. Besides, the changes in the virulence factors of Candida spp., including biphasicity, hemolytic activity, CSH, and phospholipase activity under these test conditions were investigated, and the internal relationship between these factors was analyzed. Results: The results showed that the virulence factors and antifungal susceptibility of Candida spp. could be altered through changes in various physiological conditions. Both temperature and pH were noted to be important factors affecting Candida growth, antifungal susceptibility, and expression of virulence factors. Cu2+ inhibited the growth and virulence factors expression of Candida spp., whereas antibacterial agents directly promoted the growth of Candida spp., making them resistant, which is one of the reasons for breast inflammation symptoms in cows. Conclusions: These results on virulence factors, antifungal susceptibility, and physiological characteristics of NAC provide a theoretical basis for understanding and treating dairy cow mastitis caused by NAC.

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Virulence Factors and Azole-Resistant Mechanism of Candida Tropicalis Isolated From Candidemia

10.21203/rs.3.rs-377398/v1 ◽

2021 ◽

Author(s):

Elahe Sasani ◽

Sadegh Khodavaisy ◽

Sassan Rezaie ◽

Mohammadreza Salehi ◽

Muhammad Getso ◽

...

Keyword(s):

Virulence Factors ◽

Candida Tropicalis ◽

Biofilm Formation ◽

Molecular Mechanisms ◽

Antifungal Susceptibility ◽

Cell Surface Hydrophobicity ◽

Surface Hydrophobicity ◽

Azole Resistance ◽

Virulence Determinants ◽

Fluconazole Resistant

Abstract Background Virulence factors intensify the pathogenicity of Candida species in candidemia. Limited knowledge exists regarding the azole-resistant mechanism and virulence factors of Candida tropicalis. Consequently, we aimed to evaluate the virulence factors and the molecular mechanisms of azole resistance among C. tropicalis isolated from bloodstream infection. Materials and methods Forty-five C. tropicalis isolates recovered from candidemia patients were evaluated for virulence factors, including extracellular enzymatic activities, cell surface hydrophobicity (CHS), and biofilm formation. Antifungal susceptibility pattern and expression level of ERG11, UPC2, MDR1, and CDR1 genes of eight azole resistance C. tropicalis isolates were assessed. Results The isolates expressed different frequencies of virulence determinants as follows: coagulase 4 (8.9%), phospholipase 4 (8.9 %), proteinase 31 (68.9 %), CSH 43 (95.6 %), esterase 43 (95.6 %), hemolysin 44 (97.8%), and biofilm formation 45 (100%). All the isolates were susceptible to amphotericin B and showed the highest resistance to voriconazole. The high expression of ERG11 and UPC2 genes in fluconazole-resistant C. tropicalis isolates were observed. Conclusion C. tropicalis isolated from candidemia patients extensively displayed capacities for biofilm formation, hemolysis, esterase activity, and hydrophobicity. In addition, the overexpression of ERG11 and UPC2 genes can be considered as one of the possible mechanisms of azole resistance.

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Accuracy in clinical examinations for the diagnosis of vulvovaginitis by CANDIDA SPP. and IN VITRO susceptibility to the main antifungals

Revista de Patologia Tropical / Journal of Tropical Pathology ◽

10.5216/rpt.v49i3.64233 ◽

2020 ◽

Vol 49 (3) ◽

Author(s):

Andressa Santana Santos ◽

Ana Laura Sene Amancio Zara ◽

Fábio Silvestre Ataídes ◽

Elisangela Gomes da Silva ◽

Vivianny Aparecida Queiroz Freitas ◽

...

Keyword(s):

Amphotericin B ◽

Clinical Diagnosis ◽

High Resistance ◽

Antifungal Susceptibility ◽

Vulvovaginal Candidiasis ◽

Vaginal Mucosa ◽

Candida Spp ◽

In Vitro Susceptibility ◽

Gynecology And Obstetrics

Vulvovaginal candidiasis (VVC) is a common infection. This work aims to determine the positive predictive value (PPV) of the clinical diagnosis of VVC and to characterize Candida species isolated from the vaginal mucosa. This cross-sectional study was conducted from February 2016 to February 2017 at the Gynecology and Obstetrics Outpatient Clinic of the Hospital das Clínicas, in Goiânia, Goiás State, Brazil. The study included samples of vaginal secretion from 55 women who complained of vaginal discharge and itching as their main symptoms. The PPV of the clinical diagnosis of VVC was estimated in comparison to the laboratory culture method. The phenotypic methods and molecular tests were performed to identify Candida spp. In vitro susceptibility of Candida spp. isolates to fluconazole, itraconazole, clotrimazole, nystatin, and amphotericin B was determined using the broth microdilution assay. Yeast growth using the enzymes protease, phospholipase, and hemolysin was carried out in media containing respectively bovine albumin, egg yolk, and sheep erythrocytes. A PPV of 61.8% (34/55) was determined. Among the 55 vulvovaginal samples collected, we identified 36 isolates in whichC. albicans was the most common species. High resistance to fluconazole and low minimal inhibitory concentration (MIC) values for clotrimazole, nystatin and amphotericin B were observed. All isolates were proteinase and hemolysin producers, while seven strains were phospholipase negative. The clinical diagnosis of VVC presented a moderate PPV, which meant that cultures had to be conducted in the laboratory to confirm infection. The high resistance to fluconazole and itraconazole indicated the importance of the in vitro susceptibility test.KEY WORDS: Vulvovaginal candidiasis; antifungal susceptibility; enzymatic activity

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Susceptibility to antifungal agents of Candida spp. from blood and feces collected in Novi Sad in 3-year period (2008-2010)

Zbornik Matice srpske za prirodne nauke ◽

10.2298/zmspn1121019j ◽

2011 ◽

pp. 19-26

Author(s):

Zora Jelesic ◽

Deana Medic ◽

Mira Mihajlovic-Ukropina ◽

Marija Jevtic ◽

Vera Gusman ◽

...

Keyword(s):

Candida Albicans ◽

Antifungal Agents ◽

Antifungal Susceptibility ◽

Empiric Therapy ◽

Invasive Disease ◽

Candida Spp ◽

In Vitro Susceptibility ◽

The Right ◽

Novi Sad

Candidemia is an important emerging nosocomial infection in patients with risk factors. Candida species from nonsterile sites can give insight into the characteristics of strains that may cause invasive disease. The aim of this study was to evaluate antifungal susceptibility of Candida blood and fecal isolates in Novi Sad, Vojvodina. During a 3-year period (2008 to 2010), 424 isolates of Candida spp. were collected, 30 bloodstream isolates and 394 strains from fecal samples. In vitro susceptibility of these isolates to five antifungal agents was established using commercial ATB FUNGUS 3 (Bio-M?rieux). Predominant species was Candida albicans (6 isolates from blood and 269 from feces). Resistance to one or more antifungal agents was less common in Candida albicans (3.63%) than in other species (24.83%). Resistance to itraconazole was the most commonly found in both groups of isolates, 9.64% strains from feces and 20% from blood samples. Twelve isolates were multiply resistant, usually to fluconazole, itraconazole, and voriconazole. Resistance to amphotericine B was extremely rare. Although resistance to antimycotics of Candida spp. is rare at present, continued surveillance of antifungal susceptibility is necessary in order to monitor trends, and to choose the right empiric therapy.

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Assessment of Antifungal Activity of Bakuchiol on Oral-AssociatedCandidaspp.

Evidence-based Complementary and Alternative Medicine ◽

10.1155/2015/918624 ◽

2015 ◽

Vol 2015 ◽

pp. 1-7 ◽

Cited By ~ 3

Author(s):

Mohd-Al-Faisal Nordin ◽

Fathilah Abdul Razak ◽

Wan Harun Himratul-Aznita

Keyword(s):

Antifungal Activity ◽

Metabolic Activity ◽

Antifungal Susceptibility ◽

Cell Surface Hydrophobicity ◽

Surface Hydrophobicity ◽

Inhibitory Effect ◽

Yeast Cells ◽

Planktonic Cells ◽

Specific Growth Rates

Bakuchiol is an active component ofPsoralea glandulosaandPsoralea corylifolia, used in traditional Chinese medicine. The study aimed at investigating the antifungal activity of bakuchiol on planktonic and biofilm forms of orally associatedCandidaspecies. The antifungal susceptibility testing was determined by the broth micro dilution technique. Growth kinetics and cell surface hydrophobicity (CSH) ofCandidawere measured to assess the inhibitory effect of bakuchiol onCandidaplanktonic cells. Biofilm biomass and cellular metabolic activity were quantitatively estimated by the crystal violet (CV) and the 2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-5-[(phenylamino)carbonyl]-2H-tetrazolium hydroxide (XTT) assays. AllCandidastrains have been shown to be susceptible to bakuchiol with the MIC ranges from 12.5 to 100 μg/mL. Significant decrease in specific growth rates and viable counts demonstrates the inhibitory effect of bakuchiol onCandidaplanktonic cells. A brief exposure to bakuchiol also reduced CSH ofCandida(P<0.05), indicating altered surface properties of yeast cells towards hydrophobic interfaces. Biofilm biomass and cell metabolic activity were mostly decreased, except forC. glabrata(P=0.29). The antifungal properties of bakuchiol onCandidaspecies in thisin vitrostudy may give insights into the application in therapeutic strategy againstCandidainfections.

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Antifungal susceptibility of bloodstream yeasts isolated at a public children’s hospital in Brazil: comparison of the Etest® and the AFST–EUCAST microdilution method

Canadian Journal of Microbiology ◽

10.1139/w07-095 ◽

2007 ◽

Vol 53 (12) ◽

pp. 1300-1306 ◽

Cited By ~ 7

Author(s):

Flávia E. Matsumoto ◽

Amanda L.T. Dias ◽

Márcia S.C. Melhem ◽

Maria W. Szeszs ◽

Marcos E. Auler ◽

...

Keyword(s):

Amphotericin B ◽

Susceptibility Testing ◽

Antifungal Susceptibility ◽

Candida Spp ◽

In Vitro Susceptibility ◽

Microdilution Method ◽

Susceptibility Tests ◽

Susceptibility Profiles

This study compared the minimum inhibitory concentration (MIC) results from the proposed standard methods of the Antifungal Susceptibility Testing Subcommittee of the European Committee on Antibiotic Susceptibility Testing (AFST–EUCAST) with the commercial system Etest® in the evaluation of susceptibility to flucytosine, fluconazole, itraconazole, voriconazole, and amphotericin B of 136 Candida spp. isolated from the blood of hospitalized children. The results presented a greater agreement among Etest® MICs ±2 log2 dilutions of AFST–EUCAST for fluconazole (98.1% and 96.3%) and voriconazole (100% and 100%) for Candida albicans and Candida parapsilosis . For Candida glabrata , the agreement was greater only for fluconazole (81.8%) and voriconazole (100%). For amphotericin B, the agreement between the methods was low for all species. The agreement percentage among the Etest® and AFST–EUCAST susceptibility profiles was high according to the MIC breakpoints recommended by the M27-A2 protocol for the majority of the yeasts, except for fluconazole and itraconazole against Candida tropicalis and for itraconazole against C. glabrata and Candida krusei . According to both methodologies, a great number of Candida spp. isolates showed an in vitro susceptibility to all evaluated antifungal agents. Overall, both procedures can be reliable techniques for susceptibility tests of yeasts, but the assessment of interlaboratory agreement and correlation of MICs by different methods with in vivo response are of great importance.

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146. antifungal Susceptibility Patterns of candida Parapsilosis Bloodstream Isolates in the US, 2008–2018

Open Forum Infectious Diseases ◽

10.1093/ofid/ofaa439.456 ◽

2020 ◽

Vol 7 (Supplement_1) ◽

pp. S203-S203

Author(s):

Brenda L Tesini ◽

Meghan Lyman ◽

Brendan R Jackson ◽

Anita Gellert ◽

William Schaffner ◽

...

Keyword(s):

Candida Species ◽

Regional Variation ◽

Antifungal Susceptibility ◽

Bloodstream Infections ◽

Emerging Infections ◽

In Vitro Susceptibility ◽

Fluconazole Resistance ◽

The Us ◽

Susceptibility Patterns

Abstract Background Multidrug resistant Candida is an increasing concern. C. parapsilosis in particular has decreased in vitro susceptibility to echinocandins. As a result, fluconazole had been favored for C. parapsilosis treatment. However, there is growing concern about increasing azole resistance among Candida species. We report on antifungal susceptibility patterns of C. parapsilosis in the US from 2008 through 2018. Methods Active, population-based surveillance for candidemia through the Centers for Disease Control and Prevention’s (CDC) Emerging Infections Program was conducted between 2008–2018, eventually encompassing 9 states (GA, MD,OR, TN, NY, CA, CO, MN, NM). Each incident isolate was sent to the CDC for species confirmation and antifungal susceptibility testing (AFST). Frequency of resistance was calculated and stratified by year and state using SAS 9.4 Results Of the 8,704 incident candidemia isolates identified, 1,471 (15%) were C. parapsilosis; the third most common species after C. albicans and C. glabrata. AFST results were available for 1,340 C. parapsilosis isolates. No resistance was detected to caspofungin (MIC50 0.25) or micafungin (MIC50 1.00) with only one (< 1%) isolate resistant to anidulafungin (MIC50 1.00). In contrast, 84 (6.3%) isolates were resistant to fluconazole and another 44 (3.3%) isolates had dose-dependent susceptibility to fluconazole (MIC50 1.00). Fluconazole resistance increased sharply from an average of 4% during 2008–2014 to a peak of 14% in 2016 with a subsequent decline to 6% in 2018 (see figure). Regional variation is also observed with fluconazole resistance ranging from 0% (CO, MN, NM) to 42% (NY) of isolates by site. Conclusion The recent marked increase in fluconazole resistance among C. parapsilosis highlights this pathogen as an emerging drug resistant pathogen of concern and the need for ongoing antifungal resistance surveillance among Candida species. Our data support the empiric use of echinocandins for C. parapsilosis bloodstream infections and underscore the need to obtain AFST prior to fluconazole treatment. Furthermore, regional variation in fluconazole resistance emphasizes the importance of understanding local Candida susceptibility patterns. Disclosures Lee Harrison, MD, GSK (Consultant)Merck (Consultant)Pfizer (Consultant)Sanofi Pasteur (Consultant)

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Molecular Epidemiology and Antifungal Susceptibility of Trichophyton Isolates in Greece: Emergence of Terbinafine-Resistant Trichophytonmentagrophytes Type VIII Locally and Globally

Journal of Fungi ◽

10.3390/jof7060419 ◽

2021 ◽

Vol 7 (6) ◽

pp. 419

Author(s):

Maria Siopi ◽

Ioanna Efstathiou ◽

Konstantinos Theodoropoulos ◽

Spyros Pournaras ◽

Joseph Meletiadis

Keyword(s):

Molecular Epidemiology ◽

Antifungal Susceptibility ◽

Reference Method ◽

Cross Resistance ◽

Squalene Epoxidase ◽

In Vitro Susceptibility ◽

Type Viii ◽

In Vitro Antifungal Susceptibility ◽

Resistance Rates

Trichophyton isolates with reduced susceptibility to antifungals are now increasingly reported worldwide. We therefore studied the molecular epidemiology and the in vitro antifungal susceptibility patterns of Greek Trichophyton isolates over the last 10 years with the newly released EUCAST reference method for dermatophytes. Literature was reviewed to assess the global burden of antifungal resistance in Trichophyton spp. The in vitro susceptibility of 112 Trichophyton spp. molecularly identified clinical isolates (70 T. rubrum, 24 T. mentagrophytes, 12 T. interdigitale and 6 T. tonsurans) was tested against terbinafine, itraconazole, voriconazole and amorolfine (EUCAST E.DEF 11.0). Isolates were genotyped based on the internal transcribed spacer (ITS) sequences and the target gene squalene epoxidase (SQLE) was sequenced for isolates with reduced susceptibility to terbinafine. All T. rubrum, T. interdigitale and T. tonsurans isolates were classified as wild-type (WT) to all antifungals, whereas 9/24 (37.5%) T. mentagrophytes strains displayed elevated terbinafine MICs (0.25–8 mg/L) but not to azoles and amorolfine. All T. interdigitale isolates belonged to ITS Type II, while T. mentagrophytes isolates belonged to ITS Type III* (n = 11), VIII (n = 9) and VII (n = 4). All non-WT T. mentagrophytes isolates belonged to Indian Genotype VIII and harbored Leu393Ser (n = 5) and Phe397Leu (n = 4) SQLE mutations. Terbinafine resistance rates ranged globally from 0–44% for T. rubrum and 0–76% for T. interdigitale/T. mentagrophytes with strong endemicity. High incidence (37.5%) of terbinafine non-WT T. mentagrophytes isolates (all belonging to ITS Type VIII) without cross-resistance to other antifungals was found for the first time in Greece. This finding must alarm for susceptibility testing of dermatophytes at a local scale particularly in non-responding dermatophytoses.

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Probiotic potential and safety characterization of Enterococcus hirae G24 isolated from indigenous raw goat milk

International Journal of Pharmaceutical Sciences and Drug Research ◽

10.25004/ijpsdr.2020.120303 ◽

2020 ◽

pp. 218-226

Author(s):

Kamni Rajput ◽

Ramesh Chandra Dubey

Keyword(s):

Cell Surface ◽

Pathogenic Bacteria ◽

Cell Surface Hydrophobicity ◽

Raw Milk ◽

Surface Hydrophobicity ◽

Rrna Gene ◽

Enterococcus Hirae ◽

Bacterial Cultures ◽

Probiotic Potential

In this paper, an investigation on lactic acid bacterial isolates from ethnic goat raw milk samples were examined for their probiotic potential and safety parameters. For this purpose, isolated bacterial cultures were screened based on certain parameters viz., sugar fermentation, tolerance to temperature, salt, low pH, bile salts, and phenol resistance. After that, these bacterial cultures were more estimated in vitro for auto-aggregation, cell surface hydrophobicity, response to simulated stomach duodenum channel, antibiotic resistance, and antimicrobial activity. Besides, probiotic traits show the absence of gelatinase and hemolytic activity supports its safety. The isolate G24 showed good viability at different pH, bile concentration, phenol resistance and response to simulated stomach duodenum passage but it did not show gelatinase and hemolytic activities. Isolate G24 was susceptible to amikacin, carbenicillin, kanamycin, ciprofloxacin, co-trimazine, nitrofurantoin, streptomycin, and tetracycline. Isolate G24 also exhibited antimicrobial action against five common pathogenic bacteria, such as Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Listeria monocytogens, and Salmonella typhimurium. It displayed the maximum auto-aggregation, cell surface hydrophobicity to different hydrocarbons. Following molecular characterization the isolate G24 was identified as Enterococcus hirae with 16S rRNA gene sequencing and phylogeny. E. hirae G24 bears the excellent properties of probiotics.

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Phenotypic Characterization and Molecular Identification of Intestinal Candida Spp. in Tunisia

Jundishapur Journal of Microbiology ◽

10.5812/jjm.113800 ◽

2021 ◽

Vol 14 (6) ◽

Author(s):

Khouloud Ben-Rhouma ◽

Salma Feki Ben-Salah ◽

Nada Boulehmi ◽

Aida Bouratbine

Keyword(s):

Oxidative Stress ◽

Antifungal Susceptibility ◽

Resistance Rate ◽

Phenotypic Characterization ◽

Its2 Region ◽

Candida Spp ◽

Health And Disease ◽

Stool Samples ◽

Stool Specimens

Background: Yeast naturally colonize the mammalian digestive tract and play an important role in health and disease. This community is composed of commensal yeasts, mostly Candida and Saccharomyces described as a part of the intestinal mycobiome and could be associated with resident or transient flora. Objectives: The aim of our study was to perform the phenotypic and genotypic characterization of culturable Candida isolates present in stool specimens of healthy Tunisian individuals and to evaluate their antifungal susceptibility. Methods: Yeasts were recovered from 46 stool samples cultured on Sabouraud dextrose agar at 37°C. Species were identified using conventional methods and ITS-PCR sequencing. Candida isolates were tested by exploring their tolerance to oxidative stress and extreme acidic conditions. In addition, their biofilm formation ability and in vitro resistance to antifungals was determined by the VITEK 2 system. Results: The identification by sequencing the ITS1-5.8S-ITS2 region of the 56 yeast strains isolated from 37 stool samples revealed that Candida was the dominant genus and was represented by Candida albicans (n = 21), C. parapsilosis (n = 10), C. glabrata (n = 9), and C. krusei (n = 9). In contrast, the other genera, including trichosporon, geotrichum, and rhodotorula, were sporadically occurring. We found that most Candida strains were able to form biofilms under oxidative stress and extreme pH conditions. Regarding antifungal susceptibility, a higher resistance rate to fluconazole was revealed in comparison to caspofungin and micafungin. However, nonresistance was revealed against voriconazole, amphotericin B, and 5-flucytosine. Conclusions: This is the first work-generated data on cultivable yeasts from stool specimens of healthy individuals in Tunisia. Further metagenomic studies with a larger sample size are needed to better characterize the intestinal mycobiota.

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