Inhibitory Effects of Enterococcus Strains Obtained from a Probiotic Product on In Vitro Growth of Salmonella enterica Serovar Enteritidis Strain IFO3313

2006 ◽  
Vol 69 (9) ◽  
pp. 2258-2262 ◽  
Author(s):  
WATTHANA THEPPANGNA ◽  
KOICHI OTSUKI ◽  
TOSHIYUKI MURASE
Keyword(s):  
Salmonella Enterica ◽  
Salmonella Enteritidis ◽  
Viable Cell ◽  
Mixed Cultures ◽  
Inhibitory Effects ◽  
Salmonella Enterica Serovar Enteritidis ◽  
Cell Counts ◽  
Pure Cultures ◽  
Probiotic Product

Enterococcus faecium and Enterococcus gallinarum strains were isolated from a commercial probiotic product and the effects of these strains on the growth of Salmonella enterica serovar Enteritidis strain IFO3313 were investigated. Viable cell counts of Salmonella Enteritidis in mixed cultures with the probiotic product isolate of E. faecium were significantly (P < 0.05) lower than those in pure cultures after 6, 8, and 24 h when the cultures were incubated in heart infusion broth at 37 and 41°C. Significant differences in viable cell counts of Salmonella Enteritidis in mixed cultures with the probiotic product isolate of E. gallinarum and those in pure cultures were also observed after 8 and 24 h at 37 and 41°C. Similar observations were shown in mixed cultures of Salmonella Enteritidis with the reference strains of E. faecium GIFU8355 and E. gallinarum ATCC 49573. Significant differences in viable cell counts of these enterococcal strains were not shown among pure and mixed cultures with Salmonella Enteritidis. The pH values in pure and mixed cultures were 7.0 or 7.5 throughout the experiments. E. faecium strains were found to harbor the genes encoding enterocins A and B and showed inhibitory zones with a diameter of 4 to 6 mm against growth of Salmonella Enteritidis in the enterocin production assays. However, the E. gallinarum strains possessed neither of the enterocin genes tested and exhibited no inhibition zone in the enterocin production assays. These results indicated that enterococcal strains exhibit inhibitory effects on the growth of Salmonella Enteritidis and these effects were due to both enterocin and nonenterocin factors.

scholarly journals The effects of Pinus brutia bark extract on pure and mixed continuous cultures of rumen bacteria and archaea, and fermentation characteristics in vitro

2021 ◽  
Vol 91 (5) ◽  
pp. 523-535
Author(s):  
Ahu Demirtas ◽  
◽  
Saad A. A. Musa ◽  
Yasemin Salgirli-Demirbas ◽  
Hakan Ozturk ◽  
...  
Keyword(s):  
Rumen Fermentation ◽  
Mixed Cultures ◽  
Bark Extract ◽  
Rumen Bacteria ◽  
Inhibitory Effects ◽  
Continuous Cultures ◽  
Pinus Brutia ◽  
Potential Inhibitor ◽  
Pure Cultures

The aim of the study was to investigate the effects of Pinus brutia bark extract, which is rich in polyphenolic compounds of tannins, on both pure and mixed continuous cultures of rumen bacteria and archaea, as well as on rumen fermentation characteristics in vitro. Antimicrobial susceptibility assay with pure cultures was carried out in an anaerobic chamber. Pinus brutia bark extract exhibited a potential inhibitor activity (P<0.05) against pure cultures of Ruminococcus flavefaciens, Eubacterium ruminantium, and Methanobacterium formicicum while a growth stimulatory effect (P<0.05) was observed for Ruminoccocus albus, Butyrivibrio fibrisolvens, and Streptococcus bovis. Pinus brutia bark extract only had a potential inhibitor effect (P<0.05) on R. albus at the highest dose (1200 µg/mL). Pinus brutia bark extract also stimulated (P<0.05) the growth of pure cultures of Fibrobacter succinogenes, while it did not affect Megasphaera elsdenii, except at the highest dose. The effects of two doses (75 and 375 mg/L) of P. brutia bark extract on in vitro mixed cultures and rumen fermentation parameters were determined by the rumen simulation technique (Rusitec). Supplementation with P. brutia bark extract led to a quadratic decrease (P<0.05) in the cell numbers of R. flavefaciens. Production of total and individual short chain fatty acids (SCFA), acetate to propionate ratio (C2/C3), total protozoa, ruminal pH, and dry matter digestibility (DMD) did not change in the presence of P. brutia bark extract. Supplementation with both doses of P. brutia bark extract decreased (P<0.05) the ammonia-N concentrations. Ammonia-N concentration was lowest in the high-supplemented group (P<0.05). As a conclusion, inhibitory effects of P. brutia bark extract on some species in the pure cultures were in the same direction as with mixed ruminal cultures, while stimulatory effects disappeared. The lack of inhibitory effects on protozoa and on a large number of Gram-positive rumen bacteria in the mixed cultures suggests that its mechanism of action is not exactly similar to antibiotics. Although P. brutia bark extract did not alter ruminal SCFA, it could have potential to improve ruminal protein utilization without depressing rumen microbial fermentation.

Protection of epithelial cells from Salmonella enterica serovar Enteritidis invasion by antibodies against the SPI-1 type III secretion system

2010 ◽  
Vol 56 (6) ◽  
pp. 522-526 ◽  
Author(s):  
Taseen S. Desin ◽  
Claudia S. Mickael ◽  
Po-King S. Lam ◽  
Andrew A. Potter ◽  
Wolfgang Köster
Keyword(s):  
Epithelial Cells ◽  
Type Iii Secretion ◽  
Salmonella Enterica ◽  
Salmonella Enteritidis ◽  
Secretion Systems ◽  
Salmonella Enterica Serovar Enteritidis ◽  
Specific Antibodies ◽  
Type Iii ◽  
Food Borne Illness

Salmonella enterica serovar Enteritidis (Salmonella Enteritidis) is one of the major causes of bacterial food-borne illness in humans. During the course of infection, Salmonella Enteritidis uses 2 type III secretion systems (T3SS), one of which is encoded on Salmonella pathogenicity island 1 (SPI-1). SPI-1 plays a major role in the invasion process. In the present study, we evaluated the effect of sera against the SPI-1 T3SS components on invasion in vitro using polarized human intestinal epithelial cells (Caco-2). Antisera to SipD protected Caco-2 cells against entry of wild-type Salmonella Enteritidis. On the other hand, sera against InvG, PrgI, SipA, SipC, SopB, SopE, and SopE2 did not affect Salmonella Enteritidis entry. To illustrate the specificity of anti-SipD mediated inhibition, SipD-specific antibodies were depleted from the serum. Antiserum depleted of SipD-specific antibodies lost its capacity to inhibit Salmonella Enteritidis entry. Thus, we demonstrate for the first time that antibodies against the SPI-1 needle tip protein (SipD) inhibit Salmonella Enteritidis invasion and that the SipD protein may be an important target in blocking SPI-1 mediated virulence of Salmonella Enteritidis.

Multiplication of Salmonella Enteritidis on the Yolk Membrane and Penetration to the Yolk Contents at 30°C in an In Vitro Egg Contamination Model

2008 ◽  
Vol 71 (9) ◽  
pp. 1905-1909 ◽  
Author(s):  
RICHARD K. GAST ◽  
RUPA GURAYA ◽  
JEAN GUARD-BOULDIN ◽  
PETER S. HOLT
Keyword(s):  
Salmonella Enterica ◽  
Salmonella Enteritidis ◽  
Vitelline Membrane ◽  
Critical Aspect ◽  
Salmonella Enterica Serovar Enteritidis ◽  
Exterior Surface ◽  
Increased Risk ◽  
The Mean ◽  
Uncommon Location

Refrigeration to limit bacterial multiplication is a critical aspect of efforts to control the transmission of Salmonella enterica serovar Enteritidis (SE) to consumers of contaminated eggs. Although the nutrient-rich yolk interior is an uncommon location for SE contamination in freshly laid, naturally contaminated eggs, migration across the vitelline membrane could lead to rapid bacterial multiplication even when the initial site of deposition is outside the yolk. Multiplication on the yolk membrane (before, or in addition to, multiplication within the yolk contents) could be another source of increased risk to consumers. The present study used an in vitro egg contamination model to compare the abilities of four strains of SE to either multiply in association with the yolk membrane or migrate through that membrane to reach the yolk contents during 36 h of incubation at 30°C. After inoculation onto the exterior surface of intact, whole yolks, all four SE strains penetrated the vitelline membrane to reach the yolk contents (at an overall frequency of 11.5%) after 12 h of incubation. The mean log concentration of SE was significantly higher in whole yolks (including yolk membranes) than in yolk contents at both 12 h (0.818 versus 0.167 CFU/ml) and 36 h (2.767 versus 1.402 CFU/ml) of incubation. These results demonstrate that SE multiplication on the vitelline membrane may both precede and exceed multiplication resulting from penetration into the yolk contents during the first 36 h of unrefrigerated storage, reinforcing the importance of rapid refrigeration for protecting consumers from egg-transmitted illness.

scholarly journals 1250. Novel Boronic Acid Transition State Analogs (BATSI) with in vitro inhibitory activity against class A, B and C β-lactamases

2020 ◽  
Vol 7 (Supplement_1) ◽  
pp. S643-S643
Author(s):  
Maria F Mojica ◽  
Christopher Bethel ◽  
Emilia Caselli ◽  
Magdalena A Taracila ◽  
Fabio Prati ◽  
...  
Keyword(s):  
Active Site ◽  
Inhibitory Activity ◽  
Covalent Bond ◽  
Thiol Group ◽  
Viable Cell ◽  
Free Thiol ◽  
Transition State Analogs ◽  
Cell Counts ◽  
Free Thiol Group

Abstract Background Catalytic mechanisms of serine β-lactamases (SBL; classes A, C and D) and metallo-β-lactamases (MBLs) have directed divergent strategies towards inhibitor design. SBL inhibitors act as high affinity substrates that -as in BATSIs- form a reversible, dative covalent bond with the conserved active site Ser. MBL inhibitors bind the active-site Zn2+ ions and displace the nucleophilic OH-. Herein, we explore the efficacy of a series of BATSI compounds with a free-thiol group at inhibiting both SBL and MBL. Methods Exploratory compounds were synthesized using stereoselective homologation of (+) pinandiol boronates to introduce the amino group on the boron-bearing carbon atom, which was subsequently acylated with mercaptopropanoic acid. Representative SBL (KPC-2, ADC-7, PDC-3 and OXA-23) and MBL (IMP-1, NDM-1 and VIM-2) were purified and used for the kinetic characterization of the BATSIs. In vitro activity was evaluated by a modified time-kill curve assay, using SBL and MBL-producing strains. Results Kinetic assays revealed that IC50 values ranged from 1.3 µM to &gt;100 µM for this series. The best compound, s08033, demonstrated inhibitory activity against KPC-2, VIM-2, ADC-7 and PDC-3, with IC50 in the low μM range. Reduction of at least 1.5 log10-fold of viable cell counts upon exposure to sub-lethal concentrations of antibiotics (AB) + s08033, compared to the cells exposed to AB alone, demonstrated the microbiological activity of this novel compound against SBL- and MBL-producing E. coli (Table 1). Table 1 Conclusion Addition of a free-thiol group to the BATSI scaffold increases the range of these compounds resulting in a broad-spectrum inhibitor toward clinically important carbapenemases and cephalosporinases. Disclosures Robert A. Bonomo, MD, Entasis, Merck, Venatorx (Research Grant or Support)

In Vitro Anti-Biofilm Activity of Hydrogen-Peroxide Generating Electrochemical Bandage Against Yeast Biofilms

2021 ◽  
Author(s):  
Yash S. Raval ◽  
Abdelrhman Mohamed ◽  
Jayawant N. Mandrekar ◽  
Cody Fisher ◽  
Kerryl E. Greenwood-Quaintance ◽  
...  
Keyword(s):  
Membrane Damage ◽  
Microscopic Analysis ◽  
Viable Cell ◽  
Wound Infections ◽  
Unique Challenge ◽  
Cell Membrane Damage ◽  
Cell Counts ◽  
Extensive Cell ◽  
Fluorescence Microscopic Analysis

Wound infections are caused by bacteria and/or fungi. The presence of fungal biofilms in wound beds presents a unique challenge, as fungal biofilms may be difficult to eradicate. The goal of this work was to assess the in vitro anti-biofilm activity of a H 2 O 2 -producing electrochemical bandage (e-bandage) against 15 yeast isolates representing commonly-encountered species. Time-dependent decreases in viable biofilm CFU counts of all isolates tested were observed, resulting in no visible colonies with 48 hours of exposure by plate culture. Fluorescence microscopic analysis showed extensive cell membrane damage of biofilm cells after e-bandage treatment. Reductions in intracellular ATP levels of yeast biofilm cells were recorded post e-bandage treatment. Our results suggest that exposure to H 2 O 2 -producing e-bandages reduce in vitro viable cell counts of yeast biofilms, making this a potential new topical treatment approach for fungal wound infections.

In Vitro Inhibition of the Growth of Salmonella typhimurium and Escherichia coli 0157:H7 by Bacteria Isolated from the Cecal Contents of Adult Chickens

1991 ◽  
Vol 54 (7) ◽  
pp. 496-501 ◽  
Author(s):  
ARTHUR HINTON ◽  
GEORGE E. SPATES ◽  
DONALD E. CORRIER ◽  
MICHAEL E. HUME ◽  
JOHN R. DELOACH ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Lactic Acid ◽  
Salmonella Typhimurium ◽  
Mixed Cultures ◽  
Enterococcus Durans ◽  
E Coli ◽  
Pure Cultures ◽  
In Vitro Inhibition ◽  
Lactic Acids

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&lt;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.

Multiplication and Motility of Salmonella enterica Serovars Enteritidis, Infantis, and Montevideo in In Vitro Contamination Models of Eggs

2006 ◽  
Vol 69 (5) ◽  
pp. 1012-1016 ◽  
Author(s):  
TOSHIYUKI MURASE ◽  
KAZUHIKO FUJIMOTO ◽  
RUI NAKAYAMA ◽  
KOICHI OTSUKI
Keyword(s):  
Salmonella Enterica ◽  
Salmonella Enteritidis ◽  
Egg Yolk ◽  
Vitelline Membrane ◽  
Human Patient ◽  
Polycarbonate Membrane ◽  
Specific Pathogen ◽  
Egg Albumen ◽  
Petri Plate

The invasive ability of Salmonella enterica serovars Enteritidis, Infantis, and Montevideo in eggs was examined. Strains of these serovars originating from egg contents, laying chicken houses, and human patients were experimentally inoculated (0.1-ml dose containing 78 to 178 cells) onto the vitelline membrane of eggs collected from specific-pathogen-free chickens and incubated at 25°C. The test strains were detected in 25 of 138 yolk contents by day 6, indicating the penetration of Salmonella organisms through the vitelline membrane. There were no significant differences in overall rates of penetration between serovars. The organisms were also detected in the albumen from 125 of 138 eggs tested by day 6. Growth to more than 106 CFU/ml was observed in 48 of the 125 albumen samples. An inoculum of 1,000 Salmonella cells was added to 15 ml of albumen at the edge of a petri plate. A 10-mm-diameter cylindrical well, the bottom of which was sealed with a polycarbonate membrane with 3.0-μm pores, was filled with egg yolk and placed into the albumen at the center of the dish, which was maintained at 25°C. Experiments were performed in triplicate with each strain. Salmonella organisms in all the albumen samples were detected by day 11. However, motility of the organisms toward the yolk was observed in only two dishes inoculated with the Salmonella Enteritidis strain from a human patient and in one dish inoculated with the Salmonella Infantis strain from liquid egg. The albumen samples obtained from the dishes inoculated with the Salmonella Enteritidis strain had high numbers of bacteria (&gt;108 CFU/ml). The present study suggests that Salmonella organisms in egg albumen are unlikely to actively move toward the yolk, although deposition on or near the vitelline membrane can be advantageous for proliferation.

scholarly journals Genotypic characterization of antibiotic-resistant Salmonella Enteritidis isolates in Dakar, Senegal

2007 ◽  
Vol 1 (03) ◽  
pp. 284-288 ◽  
Author(s):  
Amy Gassama Sow ◽  
Abdoul Aziz Wane ◽  
Mamadou Hadi Diallo ◽  
Cheikh Saad-Bouh Boye ◽  
Awa Aïdara-Kane
Keyword(s):  
Antibiotic Resistance ◽  
Antimicrobial Resistance ◽  
Salmonella Enterica ◽  
Salmonella Enteritidis ◽  
Data Bank ◽  
Human Infection ◽  
Molecular Techniques ◽  
Conjugative Plasmid ◽  
Bacterial Strains ◽  
Salmonella Enterica Serovar Enteritidis

Background: It is well established that Salmonella enterica is a major cause of food-borne disease worldwide. In Africa, according to the Who Global Salm-Surv country data bank from 2000 to 2002 Salmonella enterica serovar Enteritidis was the most common serotype involved in human salmonellosis. In Dakar this serotype of Salmonella has been reported as a frequent and an increasing cause of human infection. Methodology: The genetic determinants of the antimicrobial resistance of 25 selected multiresistant strains of Salmonella enterica serovar Enteritidis referred to the National Reference Center for Enterobacteria (NRCE) in Dakar were investigated using molecular techniques. Results: All strains carried blaTEM 1 genes. Five harboured three types of class 1 integrons with gene cassettes dfrA15, dfrA1-aadA1 and dfrA7. Multiresistance was due to a 23 Kb conjugative plasmid. DNA fingerprinting by macrorestriction of genomic DNA revealed a single related group suggesting that strains might be clonal. Conclusions: The spread of resistance genes through plasmid transfer plays an important role in the dissemination of antibiotic resistance in enteric pathogens such as Salmonella Enteritidis; the risk of transmissibility of antibiotic resistance between different bacterial strains highlights the urgent need to develop strategies to limit the spread of antimicrobial resistance among bacterial enteropathogens.

scholarly journals NCOA4 Mediates Ferritin Responses to Iron, Erythrophagocytosis, and Hepcidin in Macrophages (P24-056-19)

2019 ◽  
Vol 3 (Supplement_1) ◽  
Author(s):  
Cole Guggisberg ◽  
Moon-Suhn Ryu
Keyword(s):  
Iron Homeostasis ◽  
Primary Source ◽  
Viable Cell ◽  
Iron Chelator ◽  
Ammonium Citrate ◽  
Ferric Ammonium Citrate ◽  
Anemia Of Chronic Disease ◽  
Cell Counts ◽  
Subsequent Decrease

Abstract Objectives Iron recycled from erythrophagocytosis by macrophages serves as a primary source of systemic iron. NCOA4 mediates ferritin turnover via ferritinophagy. Yet, whether NCOA4 is important in macrophages or erythrophagocytosis-mediated iron recycling remains unclear, and thus was assessed in vitro. Methods J774 cells were employed as an in vitro model of macrophages. Iron studies involved treatments of ferric ammonium citrate (FAC) or an iron chelator, deferoxamine (Dfo). To recapitulate systemic iron recycling and overload, cells were treated with opsonized erythrocytes and minihepcidin, respectively. NCOA4 knock-down was achieved by siRNA transfection. Iron gene responses were measured by qPCR and western analyses, and viable cell counts were colorimetrically determined by CCK8 assays as functional outcomes. Results NCOA4 protein abundance was inversely related to iron availability and ferritin in macrophages. Loss of NCOA4 resulted in impaired ferritin turnover, and led to a reduction in viable cells when combined with iron deficiency. By erythrophagocytosis, a peak in ferritin abundance was observed at 12 h with a subsequent decrease at 24 h. This loss in ferritin was NCOA4-dependent. Minihepcidin caused accumulation of ferritin, along with a repression of NCOA4 in both control and erythrocyte-laden macrophages. Hepcidin activity had no effect on ferritin when NCOA4 was depleted. Conclusions NCOA4 mediates the release of ferritin iron during cellular iron restriction and iron recycling by macrophages. Moreover, our studies suggest that macrophage NCOA4 is integral to systemic iron homeostasis by responding to the iron regulatory hormone, hepcidin. Thus, NCOA4 and ferritinophagy may potentially serve as therapeutic targets for treatments of iron disorders and anemia of chronic disease. Funding Sources Supported by the NIFA, USDA, Hatch project under MIN-18–118 and intramural support to M-S.R.

scholarly journals Activity of pyrazinamide in a murine model against Mycobacterium tuberculosis isolates with various levels of in vitro susceptibility.

1996 ◽  
Vol 40 (1) ◽  
pp. 14-16 ◽  
Author(s):  
S P Klemens ◽  
C A Sharpe ◽  
M H Cynamon
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Drug Efficacy ◽  
Viable Cell ◽  
Test System ◽  
Infection Model ◽  
Drug Resistant ◽  
In Vitro Susceptibility ◽  
Cell Counts ◽  
Treatment Of Infection

The activity of pyrazinamide (PZA) against eight isolates of Mycobacterium tuberculosis in a murine infection model was evaluated. M. tuberculosis isolates with various degrees of in vitro susceptibility to PZA (MIC range, 32 to > 2,048 micrograms/ml) were used. Four-week-old female mice were infected intravenously with approximately 10(7) viable M. tuberculosis organisms. PZA at 150 mg/kg of body weight was started 1 day postinfection and given 5 days/week for 4 weeks. Infected but untreated mice were compared with PZA-treated mice. Mice were sacrificed at the completion of the treatment period, and viable cell counts were determined from homogenates of spleens and right lungs. PZA had activity in the murine test system against M. tuberculosis isolates for which the MICs were < or = 256 micrograms/ml. However, there was an inconsistent correlation between the absolute MICs and the reductions in organ viable cell counts. Studies with drug-resistant M. tuberculosis isolates with an isogenic background would improve evaluation of drug efficacy in the murine test system. Further evaluation of antimycobacterial agents against monodrug-resistant isolates will provide data that will be useful for development of algorithms for treatment of infection with drug-resistant organisms.

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