scholarly journals Preliminary Evaluation of In Vitro Bacteriostatic and Bactericidal Effect of Salt on Leptospira spp.

2020 ◽  
Vol 7 (4) ◽  
pp. 154
Author(s):  
Giovanni Cilia ◽  
Filippo Fratini ◽  
Elena della Buona ◽  
Fabrizio Bertelloni
Keyword(s):  
Marine Mammals ◽  
Inhibitory Concentration ◽  
Chloride Concentration ◽  
Bactericidal Effect ◽  
Preliminary Evaluation ◽  
Environmental Resistance ◽  
Leptospira Spp ◽  
Vitro Effect ◽  
Reference Strains

Environmental resistance is an important factor for understanding the epidemiology of leptospirosis. Recently, new Leptospira hosts were identified, including also marine mammals. Moreover, halotolerant Leptospira strain, isolated from the environment and animals, highlighted the capability of this microorganism to persist in the seawater. The aim of this research was to investigate the bacteriostatic and bactericidal effect of salt on Leptospira strains belonging to 16 different serovars. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values were verified through the microdilutions method starting from a 20% sodium chloride concentration. MIC values obtained were between 0.3125% and 10% of salt, while MBC values between 0.625% and >20%. Icterohaemorrhagiae (MIC: 0.3125%; MBC: 0.625%) resulted the most inhibited serovar, while the most resistant was Tarassovi (MIC: 10%; MBC: >20%). Interestingly, trends were reported for Pomona (MIC: 1.25%; MBC: >20%) and Bratislava (MIC: 0.625%; MBC: 20%), highlighting low MIC values but high MBC values. This is the first investigation aimed at the in vitro effect of salt on the growth of Leptospira spp. reference strains.

scholarly journals Bacteriostatic and Bactericidal Effect of Tigecycline on Leptospira spp.

Antibiotics ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 467
Author(s):  
Fabrizio Bertelloni ◽  
Giovanni Cilia ◽  
Filippo Fratini
Keyword(s):  
Antimicrobial Activity ◽  
Urinary Tract ◽  
Inhibitory Concentration ◽  
Minimum Bactericidal Concentration ◽  
Bactericidal Effect ◽  
Leptospira Spp ◽  
Tract Disease ◽  
Few Data ◽  
Reference Strains

Tigecycline is a relatively new antimicrobial, belonging to glycylcyclines with antimicrobial activity against a large spectrum of bacteria. Very few data are available on its effect on Leptospira spp., which consist in a bacteriostatic mechanism. The aim of this investigation was to evaluate the bacteriostatic and bactericidal effect of tigecycline on reference Leptospira strains belonging to 16 serovars. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined through the microdilutions method, and tetracycline was used as the control. Results showed that tigecycline had higher MIC and MBC values than tetracycline. Obtained MIC values were between 4 and 32 µg/mL, while MBC values between 16 and >128 µg/mL. Patoc (MIC: 4 µg/mL; MBC: 16 µg/mL) resulted in the most susceptible serovar, while the most resistant were Bataviae (MIC: 32 µg/mL; MBC: 64 µg/mL), Bratislava (MIC: 8 µg/mL; MBC 128 µg/mL), and Tarassovi (MIC: 8 µg/mL; MBC: >128 µg/mL). This is the first investigation focused on the effect of tigecycline against Leptospira spp. reference strains. Since tigecycline is used as a treatment for bacteremia and urinary tract disease, and these symptoms could be linked to Leptospira infection, the possibility of using this antibiotic as a treatment for leptospirosis should be evaluated. Further studies are needed to explore the possibility to use tigecycline for in vivo application against Leptospira.

scholarly journals Farnesol increases the activity of echinocandins against Candida auris biofilms

2019 ◽  
Vol 58 (3) ◽  
pp. 404-407 ◽  
Author(s):  
Fruzsina Nagy ◽  
Zoltán Tóth ◽  
Lajos Daróczi ◽  
Adrien Székely ◽  
Andrew M Borman ◽  
...  
Keyword(s):  
Inhibitory Concentration ◽  
Candida Auris ◽  
Independence Model ◽  
Microscope Images ◽  
Vitro Effect ◽  
Volume Range ◽  
Quorum Sensing Molecule ◽  
Bliss Independence ◽  
Scanning Electron

Abstract Candida auris biofilms exhibit decreased susceptibility to echinocandins, which is associated with poorer clinical outcomes. Farnesol is a quorum-sensing molecule enhancing the activity of antifungals; therefore, we evaluated the in vitro effect of farnesol with anidulafungin, caspofungin, or micafungin against biofilms using fractional inhibitory concentration indexes (FICI), Bliss independence model, LIVE/DEAD-assay and scanning electron microscopy. Based on mathematical models, farnesol caused synergism in eleven out of twelve cases (FICIs range 0.133-0.507; Bliss synergy volume range 70.39–204.6 μM2%). This was confirmed by microscope images of combination-exposed biofilms. Our study showed the prominent effect of farnesol with echinocandins against C. auris biofilms.

Effects of the probiotic Enterococcus faecium NCIMB 10415 on selected lactic acid bacteria and enterobacteria in co-culture

2015 ◽  
Vol 6 (3) ◽  
pp. 345-352 ◽  
Author(s):  
I.C. Starke ◽  
J. Zentek ◽  
W. Vahjen
Keyword(s):  
Intestinal Microbiota ◽  
Enterococcus Faecium ◽  
Lactobacillus Reuteri ◽  
Specific Growth ◽  
Probiotic Strain ◽  
Lactobacillus Mucosae ◽  
Vitro Effect ◽  
Reference Strains ◽  
Faecium Strain

Enterococcus faecium NCIMB 10415 is used as a probiotic for piglets and has been shown to modify the porcine intestinal microbiota. However, the mode of action of this probiotic modification is still unclear. One possible explanation is the direct growth inhibiting or stimulating effect of the probiotic on other indigenous bacteria. Therefore, the aim of the present study was to examine the growth interactions of the probiotic with different indigenous porcine bacteria in vitro. Reference strains were cultivated with the probiotic E. faecium strain NCIMB10415 (SF68) in a checkerboard assay with 102 to 105 cells/ml inoculum per strain. Growth kinetics were recorded for 8 h and used to determine specific growth of the co-cultures. Additionally, total DNA was extracted from the co-cultures at the end of the incubation to verify which strain in the co-culture was affected. Co-cultivation with eight Enterococcus spp. tester strains showed strain-specific growth differences. Three of four E. faecium strains were not influenced by the probiotic strain. PCR results showed reduced growth of the probiotic strain in co-culture with E. faecium DSM 6177. Three of four Enterococcus faecalis strains showed reduced specific growth in co-culture with the probiotic strain. However, E. faecalis DSM 20478 impaired growth of the probiotic E. faecium strain. The growth of Lactobacillus johnsonii DSM 10533 and Lactobacillus reuteri DSM 20016 was enhanced in co-culture with the probiotic strain, but co-cultivations with Lactobacillus mucosae DSM13345 or Lactobacillus amylovorus DSM10533 showed no differences. Co-cultures with the probiotic E. faecium showed no impact on the growth rate of four different enterobacterial reference strains (2 strains of Salmonella enterica and 2 strains of Escherichia coli), but PCR results showed reduced cell numbers for a pathogenic E. coli isolate at higher concentration of the probiotic strain. As the in vitro effect of the probiotic E. faecium on enterococci was strain specific and the growth of certain Lactobacillus spp. was enhanced by the probiotic, these results indicate a direct effect of the probiotic on certain members of the porcine gastro intestinal microbiota.

Antimicrobial Isothiocyanates from the Seeds of Moringa oleifera Lam.

2012 ◽  
Vol 67 (11-12) ◽  
pp. 557-564 ◽  
Author(s):  
Eleanor P. Padla ◽  
Ludivina T. Solis ◽  
Ruel M. Levida ◽  
Chien-Chang Shen ◽  
Consolacion Y. Ragasa
Keyword(s):  
Moringa Oleifera ◽  
Inhibitory Concentration ◽  
Enterobacter Aerogenes ◽  
Bactericidal Effect ◽  
Diffusion Method ◽  
Moderate Activity ◽  
Bacterial Strains ◽  
Disk Diffusion Method ◽  
Benzyl Isothiocyanate

4-(α-L-Rhamnosyloxy)benzyl isothiocyanate (1) and 4-(4’-O-acetyl-α-L-rhamnosyloxy)- benzyl isothiocyanate (2) isolated from Moringa oleifera seeds were screened for their antibacterial activities against Staphylococcus aureus, Staphylococcus epidermidis, Bacillus subtilis, Escherichia coli, Enterobacter aerogenes, Klebsiella pneumoniae, and Pseudomonas aeruginosa, and for their antifungal activities against Candida albicans, Trichophyton rubrum, and Epidermophyton floccosum using the disk diffusion method. Isothiocyanates 1 and 2 were found active at the lowest inhibitory concentration of 1 mg/ml against all Grampositive bacteria tested (S. aureus, S. epidermidis, B. subtilis) and against the dermatophytic fungi E. floccosum and T. rubrum. Statistically signifi cant differences were found between the mean inhibition zones (IZ) of 1 and 2 and the standard drugs, ofl oxacin and clotrimazole. The minimum inhibitory concentration (MIC) values confi rmed the good antimicrobial activity of 1 and 2 against S. aureus, good to moderate activity against S. epidermidis, moderate activity against B. subtilis, and weak activity against E. floccosum and T. rubrum. The in vitro bactericidal effect of 1 and 2 against the Gram-positive bacterial strains tested is suggested by MBC:MIC ratios of 2:1.

scholarly journals ​In-vitro Effect of Different Abiotic Stresses on the Growth and Sporulation of Colletotrichum gloeosporioides causing Anthracnose of Mango

2021 ◽  
Author(s):  
R. Kannan ◽  
V. Dhivya
Keyword(s):  
Fungal Pathogen ◽  
Radial Growth ◽  
Colletotrichum Gloeosporioides ◽  
Inhibitory Concentration ◽  
Culture Media ◽  
Abiotic Factors ◽  
Potato Dextrose Agar ◽  
Oatmeal Agar ◽  
Vitro Effect

Background: Mango productivity was very much affected due to a major fungal pathogen, Colletotrichum gloeosporioides causing anthracnose mango rot. The present study was carried out to investigate the influence of abiotic factors for the support of superficial growth of isolated fungus and finding a minimum inhibitory concentration of different fungicides. Methods: Among four different culture media tested, the highest radial growth and sporulation of the fungus were recorded in Oatmeal agar (OMA) (84 mm) followed by Conn’s agar (CA), Czapek Dox agar (CDA) and Potato dextrose agar (PDA). Among the different pH tested, pH 7.0 was found to be the best in supporting the good radial growth (69 mm) followed by pH 6.0 (56 mm), pH 5.5 (49 mm), pH 7.5 (43 mm) and pH 8.0 (37 mm). Among the various temperature tested, 25oC (69.32) was found to be the best followed by 20oC (52.53 mm), 30oC (65.23 mm) and 35oC. Result: Among the fungicides tested, Zineb 68% + Hexaconazole 4% WP (avtar) was found best as the radial growth was observed to be 45, 41, 36, 32, 25 mm at 5, 10, 25, 50 and 100 ppm, respectively as compared to 80 mm in control. The fungicide Tricyclazole 18% + Mancozeb 62% WP (Merger) was found to be the least effective in checking the radial growth of C. gloeosporioides even at 100 ppm concentration.

Preliminary Evaluation of Antimicrobial and Cytotoxic Activities of Extracts from Actinidia macrosperma

2012 ◽  
Vol 455-456 ◽  
pp. 1200-1203 ◽  
Author(s):  
Yin Lu ◽  
Yun Peng Zhao ◽  
Cheng Xin Fu
Keyword(s):  
Inhibitory Concentration ◽  
Chloroform Extract ◽  
Diffusion Method ◽  
Cytotoxic Activities ◽  
Preliminary Evaluation ◽  
Minimum Fungicidal Concentration ◽  
Antibacterial And Antifungal Activities ◽  
Brine Shrimp Lethality Assay ◽  
Antibacterial And Antifungal

The petroleum ether, chloroform, ethyl acetate, n-hexane and aqueous successive extracts from the stems of Actinidia macrosperma C. F. Liang have been screened for antibacterial and antifungal activities in vitro using the disc diffusion method, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC)/minimum fungicidal concentration (MFC). General toxicity of these extracts has also been assessed by brine shrimp lethality assay. The chloroform extract exhibited the most significant antimicrobial (MIC in the range of 60–500μg/ml, MBC in the range of 150–1000μg/ml, MFC in the range of 170–600μg/ml) and cytotoxic activities (LC50=16.82μg/ml at 24 hours).

In Vitro Effect of Multiple Antibiotic/Antimicrobial Residues on the Selection for Resistance in Bacteria

1992 ◽  
Vol 75 (4) ◽  
pp. 738-741 ◽  
Author(s):  
Marietta Sue Brady ◽  
Stanley E Katz
Keyword(s):  
Inhibitory Concentration ◽  
Enterobacter Cloacae ◽  
Cross Resistance ◽  
Resistance Development ◽  
Gram Negative ◽  
Antimicrobial Residues ◽  
Residue Levels ◽  
Selection For ◽  
Vitro Effect

Abstract A method using a gram-positive and a gram-negative organism was used to investigate the selection for resistant populations after exposure to residue levels of 7 antibiotics and 1 antimicrobial. The organisms were exposed to individual compounds and combinations of 3 compounds for 14 days. The changes in minimum inhibitory concentration (MIC) of a panel of 8 antibiotics and 1 antimicrobial were used as the measure of resistance development/selection. For Staphylococcus aureus ATCC 9144, exposure to residue levels of oxytetracycline, tylosin, penicillin, and virginiamycin resulted in an increased MIC of the compound itself; most individual residues did not result in increased cross-resistance. With combinations of residues, 13 of 45 determinations resulted in significant increases in MIC. Enterobacter cloacae B520, which was much less sensitive to 4 of 9 markers, showed MIC increases only for tylosin and the combination of neomycin-sulfamethazine-oxytetracycline. The results indicate an interaction among residue levels of antibiotics in selection for resistance.

scholarly journals Evaluation of Benzguinols as Next-Generation Antibiotics for the Treatment of Multidrug-Resistant Bacterial Infections

Antibiotics ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 727
Author(s):  
Hang Thi Nguyen ◽  
Mahmud T. Morshed ◽  
Daniel Vuong ◽  
Andrew Crombie ◽  
Ernest Lacey ◽  
...  
Keyword(s):  
Bacterial Infections ◽  
Inhibitory Concentration ◽  
Specific Treatment ◽  
Multidrug Resistant ◽  
Survival Times ◽  
Fungal Natural Products ◽  
Serious Bacterial Infections ◽  
Further Development ◽  
Reference Strains

Our recent focus on the “lost antibiotic” unguinol and related nidulin-family fungal natural products identified two semisynthetic derivatives, benzguinols A and B, with unexpected in vitro activity against Staphylococcus aureus isolates either susceptible or resistant to methicillin. Here, we show further activity of the benzguinols against methicillin-resistant isolates of the animal pathogen Staphylococcus pseudintermedius, with minimum inhibitory concentration (MIC) ranging 0.5–1 μg/mL. When combined with sub-inhibitory concentrations of colistin, the benzguinols demonstrated synergy against Gram-negative reference strains of Acinetobacter baumannii, Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa (MICs of 1–2 μg/mL in the presence of colistin), whereas the benzguinols alone had no activity. Administration of three intraperitoneal (IP) doses of 20 mg/kg benzguinol A or B to mice did not result in any obvious adverse clinical or pathological evidence of acute toxicity. Importantly, mice that received three 20 mg/kg IP doses of benzguinol A or B at 4 h intervals exhibited significantly reduced bacterial loads and longer survival times than vehicle-only treated mice in a bioluminescent S. aureus murine sepsis challenge model. We conclude that the benzguinols are potential candidates for further development for specific treatment of serious bacterial infections as both stand-alone antibiotics and in combination with existing antibiotic classes.

scholarly journals The long-term effect of sparkling flavored water on human tooth enamel determined by gravimetric analysis: a preliminary evaluation

2020 ◽  
Vol 23 (1) ◽  
Author(s):  
Shivaughn M Marchan ◽  
Kelee Bascombe ◽  
Trevin Hector ◽  
William AJ Smith ◽  
Terry G Ramnanansingh
Keyword(s):  
Tooth Enamel ◽  
Gravimetric Method ◽  
Dental Erosion ◽  
Human Tooth ◽  
Preliminary Evaluation ◽  
Gravimetric Analysis ◽  
Human Tooth Enamel ◽  
Flavored Water ◽  
Vitro Effect

Objective: The aim of this study was to assess the in vitro effect of flavored waters on human tooth enamel using a gravimetric method. Lingual surfaces of lower molars were used to obtain enamel specimens. Material and Methods: Enamel (n=3) was washed and dried, immersed in 6 flavors of locally available of flavored sparkling water and assessed using gravimetric analysis, periodically for up to 9 days.  Additionally, pH measurements of the flavored waters were recorded.  Results: All the tested flavored waters showed pH values below that of critical pH. Paired t-tests demonstrated significant reductions in the mean group mass for all enamel specimens from as early as day 1 after immersion in flavored water, compared to baseline measurements. Further reductions in mean mass continued up to day 9 of immersion. Conclusion: Flavored waters are potentially erosive to human enamel specimens with the erosive effect being cumulative over time.KeywordspH; Enamel; dental erosion.

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