Toxin Production by Pseudomonas Tolaasii Paine

Evidence is presented for the production of toxin in vitro and in vivo by P. tolaasii. Nutrient broth suspensions of P. tolaasii placed on detached mushroom sporophores but separated by a dialysis membrane caused brown discoloration and slightly sunken lesions.

Download Full-text

Staphylococcus aureus Serves as an Iron Source for Pseudomonas aeruginosa during In Vivo Coculture

Journal of Bacteriology ◽

10.1128/jb.187.2.554-566.2005 ◽

2005 ◽

Vol 187 (2) ◽

pp. 554-566 ◽

Cited By ~ 174

Author(s):

Lauren M. Mashburn ◽

Amy M. Jett ◽

Darrin R. Akins ◽

Marvin Whiteley

Keyword(s):

Staphylococcus Aureus ◽

Pseudomonas Aeruginosa ◽

Pathogenic Bacteria ◽

Iron Acquisition ◽

Low Oxygen ◽

Dialysis Membrane ◽

Opportunistic Human Pathogen ◽

The Impact

ABSTRACT Pseudomonas aeruginosa is a gram-negative opportunistic human pathogen often infecting the lungs of individuals with the heritable disease cystic fibrosis and the peritoneum of individuals undergoing continuous ambulatory peritoneal dialysis. Often these infections are not caused by colonization with P. aeruginosa alone but instead by a consortium of pathogenic bacteria. Little is known about growth and persistence of P. aeruginosa in vivo, and less is known about the impact of coinfecting bacteria on P. aeruginosa pathogenesis and physiology. In this study, a rat dialysis membrane peritoneal model was used to evaluate the in vivo transcriptome of P. aeruginosa in monoculture and in coculture with Staphylococcus aureus. Monoculture results indicate that approximately 5% of all P. aeruginosa genes are differentially regulated during growth in vivo compared to in vitro controls. Included in this analysis are genes important for iron acquisition and growth in low-oxygen environments. The presence of S. aureus caused decreased transcription of P. aeruginosa iron-regulated genes during in vivo coculture, indicating that the presence of S. aureus increases usable iron for P. aeruginosa in this environment. We propose a model where P. aeruginosa lyses S. aureus and uses released iron for growth in low-iron environments.

Download Full-text

Regulatory Mechanism for Exfoliative Toxin Production inStaphylococcus aureus

Infection and Immunity ◽

10.1128/iai.00872-10 ◽

2011 ◽

Vol 79 (4) ◽

pp. 1660-1670 ◽

Cited By ~ 24

Author(s):

Fuminori Kato ◽

Noriko Kadomoto ◽

Yuko Iwamoto ◽

Katsuaki Bunai ◽

Hitoshi Komatsuzawa ◽

...

Keyword(s):

Mouse Model ◽

Regulatory Mechanism ◽

Toxin Production ◽

Neonatal Mouse ◽

Epidermal Keratinocytes ◽

Global Regulators ◽

Exfoliative Toxin ◽

Blistering Disease

ABSTRACTThe exfoliative toxin (ET) is a major virulence factor ofStaphylococcus aureusthat causes bullous impetigo and its disseminated form, staphylococcal scalded-skin syndrome (SSSS). ET selectively digests one of the intracellular adhesion molecules, desmoglein 1, of epidermal keratinocytes and causes blisters due to intraepidermal cell-cell dissociation. MostS. aureusstrains that cause blistering disease produce either ETA or ETB. They are serologically distinct molecules, where ETA is encoded on a phage genome and ETB is enocded on a large plasmid. ETA-producingS. aureusstrains are frequently isolated from impetigo patients, and ETB-producingS. aureusstrains are isolated from SSSS. ET-induced blister formation can be reproduced with the neonatal mouse. To determine the regulatory mechanism of ET production, we investigated the role of the two-component systems and global regulators foretaoretbexpressionin vitroandin vivowith the mouse model. Western blot and transcription analyses using a series of mutants demonstrate ETA production was downregulated bysigB,sarS, andsarA, while ETB production was downregulated bysigBandsarAbut not bysarS. Production of both toxins is upregulated bysaeRS,arlRS, andagrCA. Furthermore, by thein vivoneonatal mouse model,sigBandsarSbut notsarAnegatively regulate the exfoliation activity of the ETA-producing strain, whilesarAnegatively regulates the ETB-producing strain. In both strains,saeRS,arlRS, andagrCApositively regulate the exfoliation activityin vivo. The data illustrate similar but distinct regulatory mechanisms for ETA and ETB productionin S. aureus in vitroas well asin vivo.

Download Full-text

Novel Dissolution Approach for Tacrolimus-Loaded Microspheres Using a Dialysis Membrane for in Vitro–in Vivo Correlation

Chemical and Pharmaceutical Bulletin ◽

10.1248/cpb.c18-01018 ◽

2019 ◽

Vol 67 (5) ◽

pp. 467-475 ◽

Cited By ~ 1

Author(s):

Masanori Kaihara ◽

Kazuhiro Hojo ◽

Tomokazu Tajiri ◽

Atsushi Kambayashi ◽

Takatsune Yoshida ◽

...

Keyword(s):

Dialysis Membrane

Download Full-text

The antibacterial activity and toxin production control of bee venom in mouse MRSA pneumonia model

BMC Complementary Medicine and Therapies ◽

10.1186/s12906-020-02991-8 ◽

2020 ◽

Vol 20 (1) ◽

Cited By ~ 1

Author(s):

Ryong Kong ◽

Young-Seob Lee ◽

Dam-Hee Kang ◽

Shu Wang ◽

Qianqian Li ◽

...

Keyword(s):

Production Control ◽

Antimicrobial Effect ◽

Toxin Production ◽

Bee Venom ◽

Dilution Method ◽

Bacterial Cells ◽

Related Gene ◽

Mrsa Infection

Abstract Background The current antimicrobial therapy is still important for the treatment of pneumonia due to MRSA infection, but there are some limitations, including the route of administration, side effect profile, and increased microbial resistance patterns. Therefore, we investigated whether BV, which shows a strong antimicrobial effect against MRSA, would be effective in a pneumonia model. Methods In vitro, we checked MIC, qRT-PCR, western blot, ELISA, LDH-assay. In vivo, we checked survival rate, gross pathological change, histopathology, lung bacterial clearance assay, and the expression of inflammatory related gene. Results The minimum inhibitory concentration of BV against MRSA is 15.6 μg/ml by broth dilution method. The production of toxins and related gene were reduced by BV in MRSA. The secretion of cytokines were decreased by treatment with BV in 264.7 RAW macrophages stimulated by MRSA Also, BV protected A549 from pathogenicity of MRSA. Bee venom reduced the number of bacteria in the lungs and alleviated the symptoms of MRSA-induced pneumonia in mouse. Conclusion BV inhibited the virulence of the bacterium and the number of bacterial cells present in lung tissue, thereby alleviating the symptoms of pneumonia in mice. This study suggested that BV may be a candidate substance for the treatment of pneumonia caused by MRSA infection.

Download Full-text

The 5′ NAD Cap of RNAIII Modulates Toxin Production in Staphylococcus aureus Isolates

Journal of Bacteriology ◽

10.1128/jb.00591-19 ◽

2019 ◽

Vol 202 (6) ◽

Cited By ~ 3

Author(s):

Hector Gabriel Morales-Filloy ◽

Yaqing Zhang ◽

Gabriele Nübel ◽

Shilpa Elizabeth George ◽

Natalya Korn ◽

...

Keyword(s):

Staphylococcus Aureus ◽

Secondary Structure ◽

Quorum Sensing ◽

Opportunistic Pathogen ◽

Toxin Production ◽

Dual Function ◽

Content Type ◽

The Stability

ABSTRACT Nicotinamide adenosine dinucleotide (NAD) has been found to be covalently attached to the 5′ ends of specific RNAs in many different organisms, but the physiological consequences of this modification are largely unknown. Here, we report the occurrence of several NAD-RNAs in the opportunistic pathogen Staphylococcus aureus. Most prominently, RNAIII, a central quorum-sensing regulator of this bacterium’s physiology, was found to be 5′ NAD capped in a range from 10 to 35%. NAD incorporation efficiency into RNAIII was found to depend in vivo on the −1 position of the P3 promoter. An increase in RNAIII’s NAD content led to a decreased expression of alpha- and delta-toxins, resulting in reduced cytotoxicity of the modified strains. These effects seem to be caused neither by changes in RNAIII’s secondary structure nor by a different translatability upon NAD attachment, as indicated by unaltered patterns in in vitro chemical probing and toeprinting experiments. Even though we did not observe any effect of this modification on RNAIII’s secondary structure or translatability in vitro, additional unidentified factors might account for the modulation of exotoxins in vivo. Ultimately, the study constitutes a step forward in the discovery of new roles of the NAD molecule in bacteria. IMPORTANCE Numerous organisms, including bacteria, are endowed with a 5′ NAD cap in specific RNAs. While the presence of the 5′ NAD cap modulates the stability of the modified RNA species, a significant biological function and phenotype have not been assigned so far. Here, we show the presence of a 5′ NAD cap in RNAIII from S. aureus, a dual-function regulatory RNA involved in quorum-sensing processes and regulation of virulence factor expression. We also demonstrate that altering the natural NAD modification ratio of RNAIII leads to a decrease in exotoxin production, thereby modulating the bacterium’s virulence. Our work unveils a new layer of regulation of RNAIII and the agr system that might be linked to the redox state of the NAD molecule in the cell.

Download Full-text

Concurrent Local Delivery of Diflunisal Limits Bone Destruction but Fails To Improve Systemic Vancomycin Efficacy during Staphylococcus aureus Osteomyelitis

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.00182-20 ◽

2020 ◽

Vol 64 (7) ◽

Cited By ~ 2

Author(s):

Thomas J. Spoonmore ◽

Caleb A. Ford ◽

Jacob M. Curry ◽

Scott A. Guelcher ◽

James E. Cassat

Keyword(s):

Staphylococcus Aureus ◽

Adjunctive Therapy ◽

Bone Destruction ◽

Standard Of Care ◽

Quorum Quenching ◽

Toxin Production ◽

Local Drug Delivery ◽

Content Type

ABSTRACT Staphylococcus aureus osteomyelitis is a debilitating infection of bone. Treatment of osteomyelitis is impaired by the propensity of invading bacteria to induce pathological bone remodeling that may limit antibiotic penetration to the infectious focus. The nonsteroidal anti-inflammatory drug diflunisal was previously identified as an osteoprotective adjunctive therapy for osteomyelitis, based on the ability of this compound to inhibit S. aureus quorum sensing and subsequent quorum-dependent toxin production. When delivered locally during experimental osteomyelitis, diflunisal significantly limits bone destruction without affecting bacterial burdens. However, because diflunisal’s “quorum-quenching” activity could theoretically increase antibiotic recalcitrance, it is critically important to evaluate this adjunctive therapy in the context of standard-of-care antibiotics. The objective of this study is to evaluate the efficacy of vancomycin to treat osteomyelitis during local diflunisal treatment. We first determined that systemic vancomycin effectively reduces bacterial burdens in a murine model of osteomyelitis and identified a dosing regimen that decreases bacterial burdens without eradicating infection. Using this dosing scheme, we found that vancomycin activity is unaffected by the presence of diflunisal in vitro and in vivo. Similarly, locally delivered diflunisal still potently inhibits osteoblast cytotoxicity in vitro and bone destruction in vivo in the presence of subtherapeutic vancomycin. However, we also found that the resorbable polyester urethane (PUR) foams used to deliver diflunisal serve as a nidus for infection. Taken together, these data demonstrate that diflunisal does not significantly impact standard-of-care antibiotic therapy for S. aureus osteomyelitis, but they also highlight potential pitfalls encountered with local drug delivery.

Download Full-text

Skor aktivitas prebiotik growol (makanan fermentasi tradisional dari singkong) terhadap Lactobacillus sp. dan Escherichia coli

Ilmu Gizi Indonesia ◽

10.35842/ilgi.v2i2.89 ◽

2019 ◽

Vol 2 (2) ◽

pp. 101

Author(s):

Puspita Mardika Sari ◽

Desty Ervira Puspaningtyas

Keyword(s):

Escherichia Coli ◽

Nutrient Broth ◽

Plate Count

Latar Belakang: Growol adalah makanan fermentasi tradisional dari singkong. Proses fermentasi diduga mampu memperbaiki karakteristik fisik tepung, meningkatkan kadar serat pangan dan kadar pati resisten. Namun demikian, potensi prebiotik dari growol terhadap perubahan bakteri saluran cerna secara in vitro belum pernah dipelajari. Tujuan: Penelitian ini bertujuan untuk mengetahui potensi prebiotik growol terhadap bakteri saluran cerna (Lactobacillus sp. dan Escherichia coli). Metode: Bahan yang digunakan adalah tepung growol sebagai produk fermentasi, tepung singkong sebagai kontrol bahan baku, glukosa sebagai kontrol substrat pada medium mikrobiologis, serta FOS dan dekstrin sebagai kontrol positif prebiotik komersial. Growol dibuat melalui fermentasi spontan yang selanjutnya dikeringkan dan digiling hingga berukuran 60 mesh menjadi tepung growol. Pengujian in vitro dilakukan pada Lactobacillus sp. dan Escherichia coli dengan menambahkan 1% (v/v) kultur ke dalam basal MRS dan basal Nutrient Broth. Pertumbuhan bakteri diukur pada jam 0, 24 dan 48 dengan metode plate count. Skor aktivitas prebiotik dihitung berdasarkan persamaan Huebner, selanjutnya data diolah dengan uji Kruskal Wallis. Hasil: Tidak terdapat perbedaan skor aktivitas prebiotik yang signifkan baik pada jam 24 (p=0,193) maupun jam 48 (p=0,244). Namun demikian semua sampel menunjukkan skor aktivitas prebiotik positif dengan nilai skor tertinggi pada jam ke 24 adalah dextrin (0,46) diikuti FOS (0,07), growol (0,04), dan singkong (0,02). Skor tertinggi pada jam ke-48 adalah FOS (8,56) diikuti growol (1,06), dekstrin (0,61), dan singkong (0,70). Kesimpulan: Singkong maupun growol berpotensi untuk dikembangkan sebagai bahan pangan sumber prebiotik. Namun demikian, penelitian lebih lanjut terutama secara in vivo diperlukan untuk mengkaji lebih lanjut mengenai potensi prebiotik growol.

Download Full-text

Alimentary and Pharmaceutical Approach to Natural Antimicrobials against Clostridioides difficile Gastrointestinal Infection

Foods ◽

10.3390/foods10051124 ◽

2021 ◽

Vol 10 (5) ◽

pp. 1124

Author(s):

Miguel Tortajada-Girbés ◽

Alejandro Rivas ◽

Manuel Hernández ◽

Ana González ◽

Maria A. Ferrús ◽

...

Keyword(s):

Toxin Production ◽

Gastrointestinal Infection ◽

Natural Antimicrobials ◽

Gastrointestinal Microbiome ◽

Clostridioides Difficile ◽

Clostridioides Difficile Infection ◽

Successful Control ◽

Marine Bioactives

Incidence of Clostridioides difficile infection (CDI) has been increasing in recent decades due to different factors, namely (i) extended use of broad-spectrum antibiotics, (ii) transmission within asymptomatic and susceptible patients, and (iii) unbalanced gastrointestinal microbiome and collateral diseases that favor C. difficile gastrointestinal domination and toxin production. Although antibiotic therapies have resulted in successful control of CDI in the last 20 years, the development of novel strategies is urged in order to combat the capability of C. difficile to generate and acquire resistance to conventional treatments and its consequent proliferation. In this regard, vegetable and marine bioactives have emerged as alternative and effective molecules to fight against this concerning pathogen. The present review examines the effectiveness of natural antimicrobials from vegetable and algae origin that have been used experimentally in in vitro and in vivo settings to prevent and combat CDI. The aim of the present work is to contribute to accurately describe the prospective use of emerging antimicrobials as future nutraceuticals and preventive therapies, namely (i) as dietary supplement to prevent CDI and reduce CDI recurrence by means of microbiota modulation and (ii) administering them complementarily to other treatments requiring antibiotics to prevent C. difficile gut invasion and infection progression.

Download Full-text

Epidemic Ribotypes Of Clostridium (Now Clostridioides) Difficile Are Likely To Be More Virulent Than Non-Epidemic Ribotypes In Animal Models

10.21203/rs.2.15921/v2 ◽

2019 ◽

Author(s):

John C. Vitucci ◽

Mark Pulse ◽

Leslie Tabor-Simecka ◽

Jerry W. Simecka

Keyword(s):

Animal Models ◽

Toxin Production ◽

Intestinal Epithelial ◽

Toxin B ◽

Golden Syrian Hamster ◽

Clostridioides Difficile ◽

Conflicting Evidence ◽

Epithelial Cell Lines

Abstract Background: Clostridioides difficile infections have become more frequently diagnosed and associated with greater disease severity, which has resulted in an increase burden on the healthcare system. These increases are attributed to the increased prevalence of hypervirulent strains encompassing select ribotypes. These epidemic ribotypes were characterized as hypervirulent due to higher in vitro spore and toxin production, as well as increased incidence, severity and mortality within patients. However, it is unclear whether epidemic ribotypes are truly more virulent than non-epidemic ribotypes in vivo. Furthermore, there is conflicting evidence about the ability of a strain’s in vitro phenotype to be predictive of their in vivo virulence. The goals of the current studies were to determine if epidemic ribotypes are more virulent than other ribotypes in animal models, and whether the in vitro virulence phenotype of an isolate or ribotype predict in vivo virulence. Results. To determine if epidemic strains were truly more virulent than other non-epidemic strains, the in vivo virulence of thirteen C. difficile isolates (7 non-epidemic and 6 epidemic ribotype isolates) were determined in murine (C57BL/6 mice) and hamster (golden Syrian hamster) models of C. difficile infections. The isolates of epidemic ribotype of C. difficile were found to be more virulent in both the murine and hamster models than non-epidemic isolates. In particular, the group of epidemic ribotypes of C. difficile had lower LD 50 values in hamsters. The increased severity of disease was associated with higher levels of Toxin A and Toxin B production found in fecal samples, but not numbers of organisms recovered. The isolates were further characterized for their in vitro virulence phenotypes, e.g. toxin production, growth rates, spore formation and adherence of spores to intestinal epithelial cell lines. Although there were higher levels of toxins produced and greater adherence for the group of epidemic ribotypes, the in vitro profiles of individual isolates were not always predictive of their in vivo virulence. Conclusions. Overall, the group of epidemic ribotypes of C. difficile were more virulent in vivo despite individual isolates having similar phenotypes to the non-epidemic isolates in vitro .

Download Full-text