scholarly journals The association between the use of antimicrobial growth promoters and development of resistance in pathogenic bacteria towards growth promoting and therapeutic antimicrobials

1998 ◽  
Vol 7 (Suppl. 1) ◽  
pp. 7-14 ◽  
Author(s):  
H. Wegener ◽  
F. Aarestrup ◽  
L. Jensen ◽  
A. Hammerum ◽  
F. Bager
Keyword(s):  
Pathogenic Bacteria ◽  
Growth Promoters ◽  
Development Of Resistance ◽  
Antimicrobial Growth Promoters ◽  
Growth Promoting

scholarly journals Autotransporter secretion exploits the bacterial actin-homologue

2018 ◽  
Author(s):  
Mahmoud M. Ashawesh ◽  
Robert Markus ◽  
Christopher N. Penfold ◽  
Kim R. Hardie
Keyword(s):  
Bacterial Infection ◽  
Virulence Factors ◽  
Pathogenic Bacteria ◽  
Super Resolution ◽  
Resistance Mechanisms ◽  
Dynamic Interaction ◽  
Bacterial Toxins ◽  
Gram Negative ◽  
Bacterial Cytoskeleton ◽  
Development Of Resistance

AbstractBacterial infection of humans, animals and plants relies heavily on secreted proteases that degrade host defences or activate bacterial toxins. The largest family of proteins secreted by Gram-negative pathogenic bacteria, the Autotransporters (ATs), includes key proteolytic virulence factors. There remains uncertainty about the mechanistic steps of the pathway ATs share to exit bacteria, and how it is energetically driven. This study set out to shed light on the AT secretion pathway with the ultimate aim of uncovering novel antimicrobial targets that would be unlikely to trigger the development of resistance mechanisms in bacteria. To do this, two AT virulence factors with distinct proteolytic functions, EspC (secreted from EnteropathogenicEscherichia coli) and AaaA (tethered to the extracellular surface ofPseudomonas aeruginosa) were chosen. EspC and AaaA were fluorescently labelled using two separate methods to establish the localization patterns of ATs as they are secreted from a bacterial cell. Super resolution microscopy revealed that localization of ATs occurs via a helical route along the bacterial cytoskeleton. In addition to requiring the conserved C-terminal β-barrel translocator domain of the AT, we present the first evidence that secretion is dependent on a dynamic interaction with a structure reliant upon the actin homologue MreB and the Sec translocon. These findings provide a step forward in the mechanistic understanding of the secretion of this widely distributed family of proteins that have pivotal roles in bacterial pathogenesis and conserved structural properties that could serve as novel broad-range antimicrobial targets.SignificanceSecreted bacterial proteases facilitate the infection of human, animal and plant hosts by degrading host defences or activating bacterial toxins. The autotransporter family is the largest family of proteins secreted from Gram-negative bacteria, and includes proteolytic virulence factors crucial to bacterial infection. Precisely how autotransporters migrate from the inside to the outside of the cell, and how this movement is energetically driven is a mystery. We demonstrate a spiral pathway of autotransporter secretion, presenting evidence that it involves a dynamic interaction with the actin homologue MreB that comprises the bacterial cytoskeleton. Our findings open the way to unravelling the mechanism of autotransporter secretion and offer the possibility to identify novel antimicrobial targets unlikely to trigger the development of antimicrobial resistance.

Piglets' gut microbiota dynamics.

2021 ◽  
Vol 16 (048) ◽  
Author(s):  
Daniela R. Klein
Keyword(s):  
Gut Microbiota ◽  
Pathogenic Bacteria ◽  
Cell Structure ◽  
Animal Health ◽  
Swine Production ◽  
Growth Promoters ◽  
Health Maintenance ◽  
Mortality And Morbidity ◽  
Weaning Piglets ◽  
The Impact

Abstract The gut microbiota has been a subject of great interest in recent years because the composition and diversity are associated with the maintenance of piglets' health and welfare. This review aims to summarise the composition and diversity of piglet microbiome, the impact on health maintenance, influence of feed and nutrients, impact of stress situations, and the effect of growth promoters and antimicrobials on gut microbiota. The composition and diversity of microbiota are influenced by animal early experiences, the appropriate development of microbiota is essential for intestinal function, and influence animal health, growth and productivity. Interactions between the gut microbiota and the immune system help maintain epithelial barrier, and protect from post-weaning diarrhoea pathogenies. After weaning, the piglets' diet changes abruptly, affecting the microbiota and the physiology, but this can be modulated through nutrients such as fibre, protein and minerals. Stress situations contribute to the appearance of intestinal disorders, possibly changing the microbiota and epithelial cell structure, facilitating colonisation of pathogenic bacteria, decreased performance and increase the use of antimicrobials. In swine production, growth promoters and antibiotics are used to reduce mortality and morbidity, especially in weaning piglets, reducing and controlling potential pathogenic bacteria, resulting in more feed intake and body weight. Antimicrobial use reduces the entire gut microbial population; the replacers are probiotics, prebiotics and organic acids, which helps maintain intestinal microbial populations, and inhibits pathogenic bacteria development. Knowing the animal microbiome dynamics helps improve immunity, productive performance and welfare, and also reduce the use of antimicrobials in animal production.

The effect of epidermal growth factor, insulin and transferrin on the growth-promoting properties of serum depleted by repeated culture of postimplantation rat embryos

Development ◽  
1988 ◽  
Vol 104 (1) ◽  
pp. 137-145
Author(s):  
M.K. Pratten ◽  
A.M. Brooke ◽  
S.C. Broome ◽  
F. Beck
Keyword(s):  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Growth Promoters ◽  
Small Molecular Weight ◽  
Rat Serum ◽  
Rat Embryos ◽  
Partial Restoration ◽  
Normal Rat ◽  
Epidermal Growth ◽  
Growth Promoting

Homologous serum, when repeatedly used for the culture of postimplantation rat embryos, rapidly loses its capacity to support growth and development. Replenishment of the ‘exhausted’ serum with glucose and vitamins (MEM vitamin concentrate—Flow Laboratories) together with gentle dialysis to remove small molecular weight toxic metabolites (lactate etc) fails to restore the growth-promoting properties of the serum. This suggests that ‘recycled’ serum has been depleted of specific growth-promoting factors. Such serum that has been subjected to dialysis can be completely replenished by addition of 30% normal rat serum. It is therefore probable that the growth promoters are originally present at very low concentrations and become rate limiting when serum is recycled. Many growth factors and hormones fall into this category and it is likely that a considerable number are involved when serum is ‘exhausted’ by repeated use. When insulin, epidermal growth factor or rat transferrin are added to dialysed ‘exhausted’ serum each effects a partial restoration of growth of rat embryos.

scholarly journals Antimicrobial growth promoters in feed – possibilities and necessity

2019 ◽  
Vol 333 ◽  
pp. 012029
Author(s):  
R Markovic ◽  
D Peric ◽  
M Laudanovic ◽  
B Baltic ◽  
S Radulovic ◽  
...  
Keyword(s):  
Growth Promoters ◽  
Antimicrobial Growth Promoters

scholarly journals Analysis of Gastrointestinal Responses Revealed Both Shared and Specific Targets of Zinc Oxide and Carbadox in Weaned Pigs

Antibiotics ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 463
Author(s):  
Yuan-Tai Hung ◽  
Qiong Hu ◽  
Richard J. Faris ◽  
Juanjuan Guo ◽  
Pedro E. Urriola ◽  
...  
Keyword(s):  
Zinc Supplementation ◽  
Growth Promotion ◽  
Wide Spectrum ◽  
Independent Effect ◽  
Growth Promoters ◽  
Nutrient Metabolism ◽  
Swine Industry ◽  
Weaning Pigs ◽  
Growth Promoting ◽  
Spectrum Evaluation

Antibiotics and pharmacological zinc supplementation were commonly used as growth promoters for several decades in the swine industry before being limited because of public health and environmental concerns. Further, the physiological and metabolic responses associated with their growth promotion effects are unclear. To characterize these responses induced by pharmacological zinc supplementation (2500 mg/kg) and carbadox (55 mg/kg), 192 post-weaning pigs were fed basal and test diets for 43 days. Compared with basal, pharmacological zinc and carbadox independently improved growth performance. Pharmacological zinc increased gastric mucosa thickness compared with basal zinc, while carbadox increased intestinal villus:crypt ratio compared with non-carbadox. Pharmacological zinc and carbadox independently reduced interleukin (IL)-1β concentration compared with basal zinc and non-carbadox. Pharmacological zinc increased IL-1RA:IL-1 ratio by 42% compared with basal zinc, while carbadox tended to increase the IL-10 and IL10:IL-12 ratio compared with non-carbadox. Carbadox increased fecal concentrations of histidine and lysine compared with non-carbadox. The independent effect of pharmacological zinc and carbadox on morphology and nutrient metabolism, and their shared effect on immunity may contribute to the additive effect on growth promotion. These results further confirmed the concept that growth promotion is multifactorial intervention. Therefore, elucidating growth-promoting effects and searching for alternatives should include wide-spectrum evaluation.

Reduction of Organoarsenical Herbicides and Antimicrobial Growth Promoters by the Legume Symbiont Sinorhizobium meliloti

2019 ◽  
Vol 53 (23) ◽  
pp. 13648-13656
Author(s):  
Yu Yan ◽  
Jian Chen ◽  
Adriana E. Galván ◽  
Luis D. Garbinski ◽  
Yong-Guan Zhu ◽  
...  
Keyword(s):  
Sinorhizobium Meliloti ◽  
Growth Promoters ◽  
Antimicrobial Growth Promoters
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