scholarly journals In vitro antifungal susceptibility of candidemia agents and detection of their biofilm production by two different methods

2017 ◽  
Vol 8 (1) ◽  
Author(s):  
Yasemin Oz ◽  
Iman Qoraan ◽  
Egemen Gokbolat
Keyword(s):  
Production Rate ◽  
Biofilm Formation ◽  
Colorimetric Assay ◽  
Formation Rate ◽  
Antifungal Susceptibility ◽  
Reference Method ◽  
Antifungal Resistance ◽  
Detection Methods ◽  
Biofilm Production

Candida bloodstream infections are a significant cause of morbidity and mortality in hospitalized patients. The most important contribution of biofilm is the higher antifungal resistance than planktonic cells. We aimed to investigate the biofilm formation rate and antifungal susceptibility characteristics of our bloodstream isolates, and evaluate two different biofilm detection methods. A total of 200 bloodstream Candida isolates were included. The biofilms were formed on 96-well microtiter plates and measured by spectrophotometric percent transmittance and 2,3-bis(2- methoxy-4-nitro-5-sulfo-phenyl)-2H-tetrazolium- 5-carboxanilide colorimetric assay. In addition antifungal susceptibilities of these isolates were evaluated against caspofungin, anidulafungin and amphotericin B by reference method. Biofilm production rate was considerably high among our bloodstream isolates. The most important biofilm producer species was C. tropicalis; C. glabrata had the lowest biofilm production rate. The consistency rate between biofilm detection methods was 66%. Remarkable antifungal resistance was not observed among our isolates in general. In conclusion, biofilm production in Candida species is an important virulence factor, and its rate is considerably high in bloodstream isolates. At present, a standardized method has not been established to detect the biofilm formation.

Molecular diagnosis and antifungal resistance and biofilm production profiles among Candida species isolated from immunocompromised patients at Menoufia University Hospitals

2020 ◽  
Vol 29 (3) ◽  
pp. 37-45
Author(s):  
Mabrouk M Ghonaim ◽  
Azza Z. Labeeb ◽  
Alyaa I. Eliwa ◽  
Eman H. Salem
Keyword(s):  
Candida Species ◽  
Biofilm Formation ◽  
Antifungal Susceptibility ◽  
High Sensitivity ◽  
Antifungal Resistance ◽  
Common Source ◽  
Immunocompromised Patients ◽  
University Hospitals ◽  
Biofilm Production ◽  
Vitek 2

Background: Accurate and rapid identification of Candida species is necessary for proper diagnosis and treatment of candidiasis due to emergences of drug-resistant strains especially among immunocompromised patients. Objectives: Identification of Candida clinical isolates to the species level using different phenotypic and molecular methods. Biofilm-forming ability and antifungal resistance were also studied. Methodology: Sixty-nine Candida strains were isolated from 220 immunocompromised patients. Identification was performed using chromogenic Candida agar, VITEK 2 system and multiplex polymerase chain reaction (PCR). Biofilm formation was detected by the tube method and antifungal susceptibility was tested using the VITEK2 system. Results: The most common source of Candida isolates was from urine (33.3%) and ICUs (56.6%). VITEK 2 system detected 9 spp.: C. albicans (34.8%), C. tropicalis (21.7%), C. famata (8.7%), C. lusitaniae (7.2%), C. cruzi (7.2%), C. ciferri (5.8%), C. dubliniensis (5.8%), C. parapsilosis (5.8 %) and C. glabrata. Candida isolates showed high resistance to flucytocine (49.3%), and high sensitivity to fluconazole, micafungin, voriconazole and caspofungin (88.4%, 81.2% and 81.2 % respectively). Only 30.4% of all Candida isolates were biofilm producers. There was a positive relationship between antifungal resistance and biofilm formation among Candida isolates. Conclusion: C. albicans was the predominant species. Chromogenic Candida agar and VITEK 2 system were valuable tests compared to PCR in speciation of Candida isolates. Antifungal susceptibility was significantly related to biofilm production and its evaluation is important for proper treatment..

Bioactivity of Phenolic Compounds Extracted from Strawberry against Formation of Pseudomonas aeruginosa Biofilm

2019 ◽  
Vol 10 (01) ◽  
Author(s):  
Baydaa Hussein ◽  
Zainab A. Aldhaher ◽  
Shahrazad Najem Abdu-Allah ◽  
Adel Hamdan
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Phenolic Compounds ◽  
Biofilm Formation ◽  
Opportunistic Infections ◽  
Formation Rate ◽  
Hydrocarbon Chain ◽  
Health Concern ◽  
Gas Chromatography Mass Spectrometry ◽  
Phenolic Contents

Background: Biofilm is a bacterial way of life prevalent in the world of microbes; in addition to that it is a source of alarm in the field of health concern. Pseudomonas aeruginosa is a pathogenic bacterium responsible for all opportunistic infections such as chronic and severe. Aim of this study: This paper aims to provide an overview of the promotion of isolates to produce a biofilm in vitro under special circumstances, to expose certain antibiotics to produce phenotypic evaluation of biofilm bacteria. Methods and Materials: Three diverse ways were used to inhibited biofilm formation of P.aeruginosa by effect of phenolic compounds extracts from strawberries. Isolates produced biofilm on agar MacConkey under certain circumstances. Results: The results showed that all isolates were resistant to antibiotics except sensitive to azithromycin (AZM, 15μg), and in this study was conducted on three ways to detect the biofilm produced, has been detected by the biofilm like Tissue culture plate (TCP), Tube method (TM), Congo Red Agar (CRA). These methods gave a clear result of these isolates under study. Active compounds were analyzed in both extracts by Gas Chromatography-mass Spectrometry which indicate High molecular weight compound with a long hydrocarbon chain. Conclusion: Phenolic compounds could behave as bioactive material and can be useful to be used in pharmaceutical synthesis. Phenolic contents which found in leaves and fruits extracts of strawberries shows antibacterial activity against all strains tested by the ability to reduce the production of biofilm formation rate.

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

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.

Use of spectrophotometric reading for in vitro antifungal susceptibility testing ofAspergillusspp.

1999 ◽  
Vol 45 (10) ◽  
pp. 871-874 ◽  
Author(s):  
Eric Dannaoui ◽  
Florence Persat ◽  
Marie-France Monier ◽  
Elisabeth Borel ◽  
Marie-Antoinette Piens ◽  
...  
Keyword(s):  
Amphotericin B ◽  
Susceptibility Testing ◽  
Clinical Laboratory ◽  
Antifungal Susceptibility ◽  
Reference Method ◽  
Antifungal Susceptibility Testing ◽  
Aspergillus Species ◽  
National Committee ◽  
Broth Microdilution Method

A comparative study of visual and spectrophotometric MIC endpoint determinations for antifungal susceptibility testing of Aspergillus species was performed. A broth microdilution method adapted from the National Committee for Clinical Laboratory Standards (NCCLS) was used for susceptibility testing of 180 clinical isolates of Aspergillus species against amphotericin B and itraconazole. MICs were determined visually and spectrophotometrically at 490 nm after 24, 48, and 72h of incubation, and MIC pairs were compared. The agreement between the two methods was 99% for amphotericin B and ranged from 95 to 98% for itraconazole. It is concluded that spectrophotometric MIC endpoint determination is a valuable alternative to the visual reference method for susceptibility testing of Aspergillus species.Key words: antifungal, susceptibility testing, Aspergillus, spectrophotometric reading.

scholarly journals Biofilm Formation by and Antifungal Susceptibility of Candida Isolates from Urine

2007 ◽  
Vol 73 (6) ◽  
pp. 1697-1703 ◽  
Author(s):  
N. Jain ◽  
R. Kohli ◽  
E. Cook ◽  
P. Gialanella ◽  
T. Chang ◽  
...  
Keyword(s):  
Risk Factors ◽  
Growth Medium ◽  
Biofilm Formation ◽  
Chart Review ◽  
Antifungal Susceptibility ◽  
Retrospective Chart Review ◽  
Urine Samples ◽  
Rpmi Medium

ABSTRACT Biofilm formation (BF) in the setting of candiduria has not been well studied. We determined BF and MIC to antifungals in Candida spp. isolates grown from urine samples of patients and performed a retrospective chart review to examine the correlation with risk factors. A total of 67 Candida spp. isolates were grown from urine samples from 55 patients. The species distribution was C. albicans (54%), C. glabrata (36%), and C. tropicalis (10%). BF varied greatly among individual Candida isolates but was stable in sequential isolates during chronic infection. BF also depended on the growth medium and especially in C. albicans was significantly enhanced in artificial urine (AU) compared to RPMI medium. In nine of the C. albicans strains BF was 4- to 10-fold higher in AU, whereas in three of the C. albicans strains and two of the C. glabrata strains higher BF was measured in RPMI medium than in AU. Determination of the MICs showed that planktonic cells of all strains were susceptible to amphotericin B (AMB) and caspofungin (CASPO) and that three of the C. glabrata strains and two of the C. albicans strains were resistant to fluconazole (FLU). In contrast, all biofilm-associated adherent cells were resistant to CASPO and FLU. The biofilms of 14 strains (28%) were sensitive to AMB (MIC50 of <1 μg/ml). Correlation between degree of BF and MIC of AMB was not seen in RPMI grown biofilms but was present when grown in AU. A retrospective chart review demonstrated no correlation of known risk factors of candiduria with BF in AU or RPMI. We conclude that BF is a stable characteristic of Candida strains that varies greatly among clinical strains and is dependent on the growth medium. Resistance to AMB is associated with higher BF in AU, which may represent the more physiologic medium to test BF. Future studies should address whether in vitro BF can predict treatment failure in vivo.

scholarly journals Molecular Investigation of Fibronectin-Binding Protein Genes and Capacity of Biofilm Production in Staphylococcus Aureus Isolated From Clinical Samples

2021 ◽  
Author(s):  
Hossein Jafari Soghondicolaei ◽  
Mohammad Ahanjan ◽  
Mehrdad Gholami ◽  
Bahman Mirzaei ◽  
Hamid Reza Goli
Keyword(s):  
Staphylococcus Aureus ◽  
Biofilm Formation ◽  
Colorimetric Assay ◽  
Binding Protein ◽  
Clinical Isolates ◽  
Diffusion Method ◽  
Clinical Samples ◽  
Biofilm Production ◽  
Fibronectin Binding Protein ◽  
Fibronectin Binding

Abstract Biofilm production increases Staphylococcus aureus resistance to antibiotics and also host defense mechanisms. The current study aims to evaluate the biofilm formation by S. aureus and to determine the prevalence of fibronectin-binding protein genes, also its correlation with drug resistance. In this study, 100 clinical isolates of S. aureus were collected. The antibiotic susceptibility pattern of the isolates was evaluated by the disk agar diffusion method. The ability of biofilm formation in the studied isolates was also determined by microplate colorimetric assay. Then, all isolates were screened by polymerase chain reaction for the fnbA and fnbB genes. Out of 100 clinical isolates of S. aureus, the highest and lowest antibiotic resistance rates were against penicillin (94%) and vancomycin (6%). Thirty-two cases were found to be multi-drug resistant (MDR) among the all strains. The ability of biofilm production was observed in 89% of the isolates. The PCR results showed that the prevalence of fnbA and fnbB genes were 91% and 17%, respectively. Moreover, 100% and 21.8% of the MDR strains harbored the fnbA and fnbB genes respectively. The ability to form biofilm in MDR isolates of S. aureus is more than non-MDR isolates, especially fnbA positive ones. As the bacteria in the biofilm are difficult to kill by antibiotics, attention to the removal or control of the biofilm production seems to be necessary.

scholarly journals In Vitro Interaction between Isavuconazole and Tacrolimus, Cyclosporin A, or Sirolimus against Aspergillus Species

2020 ◽  
Vol 6 (3) ◽  
pp. 103 ◽  
Author(s):  
Patrick Schwarz ◽  
Eric Dannaoui
Keyword(s):  
Cyclosporin A ◽  
Aspergillus Terreus ◽  
Susceptibility Testing ◽  
Inhibitory Concentration ◽  
Antifungal Susceptibility ◽  
Reference Method ◽  
Common Species ◽  
Minimal Inhibitory Concentrations ◽  
In Vitro Interaction

The interaction of isavuconazole with immunosuppressors (tacrolimus, cyclosporin A, or sirolimus) against 30 Aspergillus isolates belonging to the most common species responsible for invasive aspergillosis in humans (Aspergillus flavus, Aspergillus fumigatus, Aspergillus nidulans, Aspergillus niger, and Aspergillus terreus) was evaluated in vitro by a microdilution checkerboard technique based on the EUCAST reference method for antifungal susceptibility testing. The interpretation of the results was performed based on the fractional inhibitory concentration index. The combination of isavuconazole with tacrolimus, cyclosporin A, or sirolimus, was synergistic for 56, 20, or 10% of the isolates, respectively. Interestingly synergy of the combination of isavuconazole with tacrolimus was also achieved for the majority of azole-resistant isolates of A. fumigatus, and for all A. niger isolates with isavuconazole minimal inhibitory concentrations ≥ 8 µg/mL. Antagonistic interactions were never observed for any combination tested.

scholarly journals Evaluation of the Effectiveness of Crotoxin as an Antiseptic against Candida spp. Biofilms

Toxins ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 532
Author(s):  
Amanda Pissinatti Canelli ◽  
Taís Fernanda dos Santos Rodrigues ◽  
Vivian Fernandes Furletti de Goes ◽  
Guilherme Ferreira Caetano ◽  
Maurício Ventura Mazzi
Keyword(s):  
Biofilm Formation ◽  
Colorimetric Assay ◽  
Oral Candidiasis ◽  
Hacat Cells ◽  
Candida Spp ◽  
Oral Infections ◽  
Minimum Fungicidal Concentration ◽  
Antimicrobial Susceptibility Tests ◽  
Susceptibility Tests

The growing number of oral infections caused by the Candida species are becoming harder to treat as the commonly used antibiotics become less effective. This drawback has led to the search for alternative strategies of treatment, which include the use of antifungal molecules derived from natural products. Herein, crotoxin (CTX), the main toxin of Crotalus durissus terrificus venom, was challenged against Candida tropicalis (CBS94) and Candida dubliniensis (CBS7987) strains by in vitro antimicrobial susceptibility tests. Minimum inhibitory concentration (MIC), minimum fungicidal concentration (MFC), and inhibition of biofilm formation were evaluated after CTX treatment. In addition, CTX-induced cytotoxicity in HaCaT cells was assessed by MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) colorimetric assay. Native CTX showed a higher antimicrobial activity (MIC = 47 μg/mL) when compared to CTX-containing mouthwash (MIC = 750 μg/mL) and nystatin (MIC = 375 μg/mL). Candida spp biofilm formation was more sensitive to both CTX and CTX-containing mouthwash (IC100 = 12 μg/mL) when compared to nystatin (IC100 > 47 μg/mL). Moreover, significant membrane permeabilization at concentrations of 1.5 and 47 µg/mL was observed. Native CTX was less cytotoxic to HaCaT cells than CTX-containing mouthwash or nystatin between 24 and 48 h. These preliminary findings highlight the potential use of CTX in the treatment of oral candidiasis caused by resistant strains.

scholarly journals Association between Biofilm-Production and Antibiotic Resistance in Uropathogenic Escherichia coli (UPEC): An In Vitro Study

Diseases ◽  
2020 ◽  
Vol 8 (2) ◽  
pp. 17 ◽  
Author(s):  
Payam Behzadi ◽  
Edit Urbán ◽  
Márió Gajdács
Keyword(s):  
Escherichia Coli ◽  
Biofilm Formation ◽  
In Vitro Study ◽  
Point Of View ◽  
Diffusion Method ◽  
Medical Attention ◽  
Disk Diffusion Method ◽  
Biofilm Production ◽  
Tract Infections

Urinary tract infections (UTIs) are among the most common infections requiring medical attention worldwide. The production of biofilms is an important step in UTIs, not only from a mechanistic point of view, but this may also confer additional resistance, distinct from other aspects of multidrug resistance (MDR). A total of two hundred and fifty (n = 250) Escherichia coli isolates, originating from clean-catch urine samples, were included in this study. The isolates were classified into five groups: wild-type, ciprofloxacin-resistant, fosfomycin-resistant, trimethoprim-sulfamethoxazole-resistant and extended spectrum β-lactamase (ESBL)-producing strains. The bacterial specimens were cultured using eosine methylene blue agar and the colony morphology of isolates were recorded. Antimicrobial susceptibility testing was performed using the Kirby–Bauer disk diffusion method and E-tests. Biofilm-formation of the isolates was carried out with the crystal violet tube-adherence method. n = 76 isolates (30.4%) produced large colonies (>3 mm), mucoid variant colonies were produced in n = 135 cases (54.0%), and n = 119 (47.6%) were positive for biofilm formation. The agreement (i.e., predictive value) of mucoid variant colonies in regard to biofilm production in the tube-adherence assay was 0.881 overall. Significant variation was seen in the case of the group of ESBL-producers in the ratio of biofilm-producing isolates. The relationship between biofilm-production and other resistance determinants has been extensively studied. However, no definite conclusion can be reached from the currently available data.

scholarly journals Colistin and Isavuconazole Interact Synergistically In Vitro against Aspergillus nidulans and Aspergillus niger

2020 ◽  
Vol 8 (9) ◽  
pp. 1447
Author(s):  
Patrick Schwarz ◽  
Elie Djenontin ◽  
Eric Dannaoui
Keyword(s):  
Aspergillus Niger ◽  
Aspergillus Nidulans ◽  
Susceptibility Testing ◽  
Antifungal Susceptibility ◽  
Reference Method ◽  
Important Species ◽  
Agar Diffusion ◽  
Agar Diffusion Assay ◽  
Diffusion Assay

The in vitro interactions of isavuconazole in combination with colistin were evaluated against 55 clinical Aspergillus species isolates belonging to the five most important species (Aspergillus flavus, Aspergillus fumigatus, Aspergillus nidulans, Aspergillus niger, and Aspergillus terreus) responsible for human aspergillosis by a microdilution checkerboard technique based on the European Committee on Antimicrobial Susceptibility Testing (EUCAST) reference method for antifungal susceptibility testing. Selected isolates (A. nidulans, n = 10; A. niger, n = 15) were additionally evaluated by an agar diffusion assay using isavuconazole gradient concentration strips with or without colistin incorporated Roswell Parc Memorial Institute (RPMI) agar. Interpretation of the checkerboard results was done by the fractional inhibitory concentration index. Using the checkerboard method, combination isavuconazole–colistin was synergistic for 100% of the 15 A. nidulans isolates and for 60% of the 20 A. niger isolates. No interactions were found for any of the other isolates. By agar diffusion assay, minimal inhibitory concentrations (MICs) in combination decreased compared to isavuconazole alone for 92% of the isolates. No interactions were found for any A. nidulans isolates, but synergy was observed for 40% of the A. niger isolates. A poor essential agreement of EUCAST and gradient concentration strip MICs at ± 2 log2 dilutions with 0% was obtained. Antagonistic interactions were never observed regardless of the technique used.

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