Increased in vitro sensitivity of Candida albicans to amphotericin B when grown in mixed culture with Escherichia coli

1978 ◽  
Vol 24 (12) ◽  
pp. 1482-1489 ◽  
Author(s):  
L. G. Mathieu ◽  
D. Dube ◽  
M. Lebrun

The growth of Candida albicans was inhibited by some Escherichia coli strains both in conventional batch cultures and also in a chemostat under conditions of constant addition of fresh medium. Concentrations of 0.2 μg amphotericin B per millilitre and of 2 μg nystatin per millilitre, which caused a slight inhibition of C. albicans in pure culture, exerted a strong fungicidal effect when the yeast was placed in mixed cultures with certain strains of E. coli. Candida albicans cells, inhibited by either E. coli or in mixed culture with polyene antibiotics, appeared larger and less uniformly stained by acridine orange than control cells from pure cultures. Addition of chloramphenicol to the mixed cultures, in quantities sufficient to kill the E. coli cells, abolished the increased sensitivity of C. albicans to amphotericin B or nystatin. In preliminary in vivo tests, E. coli did not sensitize C. albicans to the polyene antibiotics.

1991 ◽  
Vol 54 (7) ◽  
pp. 496-501 ◽  
Author(s):  
ARTHUR HINTON ◽  
GEORGE E. SPATES ◽  
DONALD E. CORRIER ◽  
MICHAEL E. HUME ◽  
JOHN R. DELOACH ◽  
...  

A Veillonella species and Enterococcus durans were isolated from the cecal contents of adult broilers. Mixed cultures of Veillonella and E. durans inhibited the growth of Salmonella typhimurium and Escherichia coli 0157:H7 on media containing 2.5% lactose (w/v). The growth of S. typhimurium or E. coli 0157:H7 was not inhibited by mixed cultures containing Veillonella and E. durans on media containing only 0.25% lactose or by pure cultures of Veillonella or E. durans on media containing either 0.25% or 2.5% lactose. The mixed cultures of Veillonella and E. durans produced significantly (P<0.05) more acetic, propionic, and lactic acids in media containing 2.5% lactose than in media containing 0.25% lactose. The inhibition of the enteropathogens was related to the production of lactic acid from lactose by the E. durans and the production of acetic and propionic acids from lactic acid by the Veillonella.


2020 ◽  
Vol 151 ◽  
pp. 15550-15558
Author(s):  
Amégninou Agban ◽  
Yao Hoekou ◽  
Passimna Pissang ◽  
Tchadjobo Tchacondo ◽  
Komlan Batawila

Objectif : L’objectif de ce travail était d’évaluer in vitro l’activité antimicrobienne des extraits de feuilles et tige de Jatropha multifida sur la croissance de Candida albicans, Escherichia coli et Staphylococcus aureus, puis d’évaluer in vivo la toxicité de cette plante. Méthodologie et résultats : Les méthodes de diffusion en milieu gélosé et de microdilution en milieu liquide ont été utilisées pour évaluer l’effet antimicrobien. Une étude en subaigüe était réalisée afin d’explorer les effets toxiques de l’extrait aqueux des feuilles. Les résultats des tests antimicrobiens montrent une activité des extraits de feuilles et tige de J. multifida sur la croissance des souches utilisées avec des diamètres de zones d’inhibition allant de 8 à 25 mm et des concentrations minimales inhibitrices (CMI) variant de 0,039 mg/mL à 1,25 mg/mL à l’exception des souches de E. coli qui sont résistantes aux extraits de la tige. L’administration en subaigüe de l’extrait aqueux des feuilles de J. multifida à la dose de 600 mg/kg entraîne une perte significative de poids chez les souris. Conclusion et applications des résultats : Les extraits aqueux, éthanolique et hydroéthanolique des feuilles et tige de J. multifida possèdent d’activité antimicrobienne et pourraient être utilisés dans le traitement des Candidoses à C. albicans et des infections à S. aureus. Mais l’essai de toxicité subaigüe montre que l’extrait aqueux de la plante serait toxique. Des études toxicologiques approfondies restent donc nécessaires sur ces extraits afin de mieux élucider leur inocuité. Mots-clés : Jatropha multifida, extraits de feuilles et de tige, activités antifongique et antibactérienne, toxicité. Agban et al., J. Appl. Biosci. 2020 Evaluation du potentiel antimicrobien et de la toxicité des extraits de Jatropha multifida Linn, (Euphorbiaceae) 15551 Evaluation of antimicrobial potential and toxicity of Jatropha multifida Linn, (Euphorbiaceae) extracts ABSTRACT Objective: The objective of this study was to evaluate in vitro the antimicrobial activity of leaves and stem of Jatropha multifida extracts against Candida albicans, Escherichia coli and Staphylococcus aureus, and then to evaluate in vivo the toxicity of this plant. Methodology and Results: The agar well-diffusion and the NCCLS broth microdilution methods were used to assess the antimicrobial effect. A subacute study was carried out to explore the toxic effects of the aqueous extract of the leaves. The results of the antimicrobial tests show an activity of the extracts of leaves and stems of J. multifida on the growth of the strains used with diameters of inhibitory zones ranging from 8 to 25 mm and minimum inhibitory concentrations (MIC) varying from 0.039 mg/mL to 1.25 mg/mL exception E. coli strains which are resistant to extracts from the stem. Subacute administration of the aqueous extract of the leaves of J. multifida at a dose of 600 mg/kg leads to a significant loss of weight in the mice. Conclusion and application of findings : The aqueous, ethanolic and hydroethanolic extracts of the leaves and stem of J. multifida have antimicrobial activity and could be used in the treatment of Candidiasis and bacterial infections due respectively to C. albicans and S. aureus. But the subacute toxicity test shows that the aqueous extract of the plant would be toxic. Extensive toxicological studies therefore remain necessary on these extracts in order to better elucidate their safety. Keywords: Jatropha multifida extracts of leaves and stem, antifungal and antibacterial activities, toxicity


2001 ◽  
Vol 45 (1) ◽  
pp. 243-251 ◽  
Author(s):  
Lorna E. T. Stearne ◽  
Clarissa Kooi ◽  
Wil H. F. Goessens ◽  
Irma A. J. M. Bakker-Woudenberg ◽  
Inge C. Gyssens

ABSTRACT To determine the efficacy of trovafloxacin as a possible treatment for intra-abdominal abscesses, we have developed an anaerobic time-kill technique using different inocula to study the in vitro killing ofBacteroides fragilis in pure culture or in mixed culture with either Escherichia coli or a vancomycin-resistant strain of Enterococcus faecium (VREF). With inocula of 5 × 105 CFU/ml and trovafloxacin concentrations of ≤2 μg/ml, a maximum observed effect (E max) of ≥6.1 (log10 CFU/ml) was attained with all pure and mixed cultures within 24 h. With inocula of 108CFU/ml, a similar E max and a similar concentration to produce 50% of E max(EC50) for B. fragilis were found in both pure cultures and mixed cultures with E. coli. However, to produce a similar killing of B. fragilis in the mixed cultures with VREF, a 14-fold increase in the concentration of trovafloxacin was required. A vancomycin-susceptible strain of E. faecium and a trovafloxacin-resistant strain of E. coli were also found to confer a similar “protective” effect on B. fragilis against the activity of trovafloxacin. Using inocula of 109 CFU/ml, the activity of trovafloxacin was retained for E. coli and B. fragilis and was negligible against VREF. We conclude that this is a useful technique to study the anaerobic killing of mixed cultures in vitro and may be of value in predicting the killing of mixed infections in vivo. The importance of using mixed cultures and not pure cultures is clearly shown by the difference in the killing of B. fragilis in the mixed cultures tested. Trovafloxacin will probably be ineffective in the treatment of infections involving large numbers of enterococci. However, due to its ability to retain activity against large cultures of B. fragilis and E. coli, trovafloxacin could be beneficial in the treatment of intra-abdominal abscesses.


Author(s):  
В.Г. Арзуманян ◽  
А.М. Иксанова ◽  
Т.А. Артемьева ◽  
Л.М. Бутовченко ◽  
Е.Т. Мальбахова

Широкое использование антибиотиков и противогрибковых препаратов при лечении дисбиозов влагалища сопровождается появлением резистентных штаммов микроорганизмов. В этой связи актуальной является разработка новых препаратов, в частности, основанных на натуральных антимикробных пептидах (АМП), отличающихся более широким спектром действия и высокой активностью. Цель работы - изучение возможности использования сывороточных АМП в лечении вагинальных дисбиозов различной этиологии на мышиной модели. Методика. Активность АМП фракции сыворотки крови кролика оценивали в опытах in vitro и in vivo. В первом случае проверяли действие АМП на клетки Candida albicans, Escherichia coli и Staphylococcus aureus спектрофотометрическим методом. Данный метод основан на поглощении красителя бромкрезолового пурпурного клетками с нарушенной цитоплазматической мембраной и, как результат, снижении оптической плотности надосадочной жидкости в опытных вариантах по сравнению с контрольными. Во втором случае оценивали лечебный эффект концентрированного препарата сывороточных АМП на мышах, зараженных интравагинально теми же культурами. После заражения мышей пролечивали введением препарата тем же путем, а результат оценивали методом высевов из влагалища на селективные среды. Результаты. Установлено, что наиболее выраженное действие в опытах in vitro сывороточные АМП оказывали на клетки C. albicans (активность составила 32,9 % от контроля), тогда как менее выраженный эффект имел место в отношении E. coli (23,3 %) и S. aureus (14,4 %). Аналогичная закономерность имела место и в опытах in vivo: высев C. albicans после лечения препаратом АМП составил 44,6% от исходного в сравнении с 42,2% после лечения пимафуцином и 90,2% без лечения (плацебо); высев E. coli - 65,6% от исходного в сравнении с 26,3% после лечения метронидазолом и 94,8% в варианте плацебо; высев S. aureus - 76,9% от исходного в сравнении с 11,4% после лечения клиндамицином и 73,0% в варианте плацебо. Заключение. Наибольшей чувствительностью к сывороточным АМП среди изученных видов обладали клетки C. albicans, а наименьшей - S. aureus, причем как в опытах in vitro, так и in vivo. Препарат на основе АМП фракции сыворотки крови можно рассматривать как альтернативу традиционным препаратам при лечении вагинальных дисбиозов, особенно вульвовагинального кандидоза. Extensive use of antibiotics and antimycotics in the treatment of vaginal dysbiosis may result in emergence of resistant microbial strains. Therefore, development of new, broad-spectrum and highly active drugs, particularly based on antimicrobial peptides (AMP) is relevant. The aim of the present study was to evaluate a possibility of using serum AMP in the treatment of vaginal dysbiosis of different etiology on a murine model. Methods. Activity of the AMP fraction of rabbit serum was evaluated in in vitro and in vivo experiments. In the in vitro experiment, the effect of AMP on Candida albicans, Escherichia coli, and Staphylococcus aureus cells was measured spectrophotometrically. This method was based on uptake of the bromocresol purple stain by cytoplasmic membranes of destroyed cells, which resulted in decreased optical density of the supernatant in experimental variants compared to the control. In the in vivo experiments, the therapeutic effect of concentrated serum AMP was evaluated in mice intravaginally infected with the same microbial cultures. The infected mice were treated similarly with the AMP preparation, and the outcome was evaluated using the inoculation of plates with selective media by vaginal material. Results. The serum AMP fraction exerted the most noticeable effect in in vitro experiments on C. albicans cells (activity 32.9 % of control) vs. lower effects on E. coli (23.3 %) and S. aureus (14.4 %). Consistently in the in vivo experiments, the abundance of C. albicans colonies was 44.6% of the initial value after the AMP drug treatment compared to 42.2% after the pimafucin treatment and 90.2% in placebo. The abundance of E. coli colonies after the AMP drug treatment was 65.6% of the initial compared to 26.3% after the metronidazole treatment and 94.8% in placebo; for S. aureus, the abundance was 76.9% (AMP) compared to 11.4% (clindamycin) and 73.0% (placebo). Conclusion. Among the studied microorganisms, C. albicans had the highest susceptibility to serum AMP while S. aureus was the least susceptible both in in vitro and in vivo experiments. Drugs based on the serum AMP preparation may be considered as a possible alternative to traditional medications for the treatment of vaginal dysbiosis, especially for vulvovaginal candidiasis.


2020 ◽  
Vol 24 (19) ◽  
pp. 2272-2282
Author(s):  
Vu Ngoc Toan ◽  
Nguyen Minh Tri ◽  
Nguyen Dinh Thanh

Several 6- and 7-alkoxy-2-oxo-2H-chromene-4-carbaldehydes were prepared from corresponding alkyl ethers of 6- and 7-hydroxy-4-methyl-2-oxo-2H-chromen-2-ones by oxidation using selenium dioxide. 6- and 7-Alkoxy-4-methyl-2H-chromenes were obtained with yields of 57-85%. Corresponding 4-carbaldehyde derivatives were prepared with yields of 41-67%. Thiosemicarbazones of these aldehydes with D-galactose moiety were synthesized by reaction of these aldehydes with N-(2,3,4,6-tetra-O-acetyl-β-Dgalactopyranosyl) thiosemicarbazide with yields of 62-74%. These thiosemicarbazones were screened for their antibacterial and antifungal activities in vitro against bacteria, such as Staphylococcus aureus, Escherichia coli, and fungi, such as Aspergillus niger, Candida albicans. Several compounds exhibited strong inhibitory activity with MIC values of 0.78- 1.56 μM, including 8a (against S. aureus, E. coli, and C. albicans), 8d (against E. coli and A. niger), 9a (against S. aureus), and 9c (against S. aureus and C. albicans).


1987 ◽  
Vol 248 (1) ◽  
pp. 43-51 ◽  
Author(s):  
J Charlier ◽  
R Sanchez

In contrast with most aminoacyl-tRNA synthetases, the lysyl-tRNA synthetase of Escherichia coli is coded for by two genes, the normal lysS gene and the inducible lysU gene. During its purification from E. coli K12, lysyl-tRNA synthetase was monitored by its aminoacylation and adenosine(5′)tetraphospho(5′)adenosine (Ap4A) synthesis activities. Ap4A synthesis was measured by a new assay using DEAE-cellulose filters. The heterogeneity of lysyl-tRNA synthetase (LysRS) was revealed on hydroxyapatite; we focused on the first peak, LysRS1, because of its higher Ap4A/lysyl-tRNA activity ratio at that stage. Additional differences between LysRS1 and LysRS2 (major peak on hydroxyapatite) were collected. LysRS1 was eluted from phosphocellulose in the presence of the substrates, whereas LysRS2 was not. Phosphocellulose chromatography was used to show the increase of LysRS1 in cells submitted to heat shock. Also, the Mg2+ optimum in the Ap4A-synthesis reaction is much higher for LysRS1. LysRS1 showed a higher thermostability, which was specifically enhanced by Zn2+. These results in vivo and in vitro strongly suggest that LysRS1 is the heat-inducible lysU-gene product.


2005 ◽  
Vol 49 (6) ◽  
pp. 2343-2351 ◽  
Author(s):  
Patricia Komp Lindgren ◽  
Linda L. Marcusson ◽  
Dorthe Sandvang ◽  
Niels Frimodt-Møller ◽  
Diarmaid Hughes

ABSTRACT Resistance to fluoroquinolones in urinary tract infection (UTIs) caused by Escherichia coli is associated with multiple mutations, typically those that alter DNA gyrase and DNA topoisomerase IV and those that regulate AcrAB-TolC-mediated efflux. We asked whether a fitness cost is associated with the accumulation of these multiple mutations. Mutants of the susceptible E. coli UTI isolate Nu14 were selected through three to five successive steps with norfloxacin. Each selection was performed with the MIC of the selected strain. After each selection the MIC was measured; and the regions of gyrA, gyrB, parC, and parE, previously associated with resistance mutations, and all of marOR and acrR were sequenced. The first selection step yielded mutations in gyrA, gyrB, and marOR. Subsequent selection steps yielded mutations in gyrA, parE, and marOR but not in gyrB, parC, or acrR. Resistance-associated mutations were identified in almost all isolates after selection steps 1 and 2 but in less than 50% of isolates after subsequent selection steps. Selected strains were competed in vitro, in urine, and in a mouse UTI infection model against the starting strain, Nu14. First-step mutations were not associated with significant fitness costs. However, the accumulation of three or more resistance-associated mutations was usually associated with a large reduction in biological fitness, both in vitro and in vivo. Interestingly, in some lineages a partial restoration of fitness was associated with the accumulation of additional mutations in late selection steps. We suggest that the relative biological costs of multiple mutations may influence the evolution of E. coli strains that develop resistance to fluoroquinolones.


1993 ◽  
Vol 296 (3) ◽  
pp. 851-857 ◽  
Author(s):  
T Belyaeva ◽  
L Griffiths ◽  
S Minchin ◽  
J Cole ◽  
S Busby

The Escherichia coli cysG promoter has been subcloned and shown to function constitutively in a range of different growth conditions. Point mutations identify the -10 hexamer and an important 5′-TGN-3′ motif immediately upstream. The effects of different deletions suggest that specific sequences in the -35 region are not essential for the activity of this promoter in vivo. This conclusion was confirmed by in vitro run-off transcription assays. The DNAase I footprint of RNA polymerase at the cysG promoter reveals extended protection upstream of the transcript start, and studies with potassium permanganate as a probe suggest that the upstream region is distorted in open complexes. Taken together, the results show that the cysG promoter belongs to the ‘extended -10’ class of promoters, and the base sequence is similar to that of the P1 promoter of the E. coli galactose operon, another promoter in this class. In vivo, messenger initiated at the cysG promoter appears to be processed by cleavage at a site 41 bases downstream from the transcript start point.


2017 ◽  
Vol 83 (4) ◽  
pp. 391-402
Author(s):  
Jhanina Rodríguez Carrasco ◽  
Paula García-Godos Alcázar

La investigación tuvo como objetivos aislar e identificar bacterias lácticas (BAL), evaluar la capacidad probiótica in vitro e in vivo de bacterias lácticas aisladas de chicha de molle, para ello se muestreó chichas de molle elaboradas artesanalmente de las provincias de Huanta y Huamanga, aislando 55 cepas BAL e identificando a Lactobacillus plantarum, Lactobacillus maltaromicus y Leuconostoc mesenteroides en base a la coloración Gram, producción de gas, gluconato y fermentación de azúcares. Para evaluar la capacidad probiótica in vitro se realizaron pruebas de antagonismo entre BAL con cuatro microorganismos patógenos (Escherichia coli ATCC 25922, Salmonella typhimurium ATCC 14028, Staphylococus aureus ATCC 25923 y Candida albicans ATCC 90028), mostrándose que 14 de las 55 cepas BAL producen sustancias inhibitorias de amplio espectro; asimismo, se evaluó la capacidad de tolerancia a condiciones gastrointestinales de cepas BAL, realizando ensayos a diferentes pHs , diferentes concentraciones de sales biliares y extracto gástrico artificial, resultando 25 cepas BAL con capacidad de tolerancia gastrointestinal y se seleccionaron cuatro cepas con mayor diámetro de halos de inhibición y cepas tolerantes a condiciones gastrointestinales siendo las cepas: BL-1 (Lactobacillus plantarum), BL-26 (Lactobacillus maltaromicus), BL-27 (Lactobacillus plantarum) y BL-53 (Lactobacillus maltaromicus), a las cuales se evaluaron la capacidad probiótica in vivo en 20 ratas para luego realizar recuento de BAL en el intestino a los 21 días, encontrándose en el grupo de estudio con BAL a 60x1019 UFC/ mL, mientras en el tratamiento con BAL más yacón a 25x1024 UFC/mL y los tratamientos de yacón y control a 50x1014 UFC/mL de BAL obteniéndose una de ganancia de peso en ratas en el grupo de estudio de BAL más yacón de 46 g, mientras con bacterias lácticas se tuvo 24 g y 16 g en el grupo control y extracto de yacón. En consecuencia esta investigación demuestra que la toma diaria de bebidas fermentadas tradicionales favorece el incremento de Lactobacillus en la microbiota intestinal.


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