Bacteria rapidly colonize and modulate healing of gastric ulcers in rats

1998 ◽  
Vol 275 (3) ◽  
pp. G425-G432 ◽  
Author(s):  
Susan N. Elliott ◽  
André Buret ◽  
Webb McKnight ◽  
Mark J. S. Miller ◽  
John L. Wallace
Keyword(s):  
Ulcer Healing ◽  
Bacterial Colonization ◽  
Healing Process ◽  
Gastric Ulcers ◽  
Gram Negative Bacteria ◽  
Antibiotic Resistant ◽  
Gram Negative ◽  
E Coli ◽  
Beneficial Effects ◽  
The Relationship

The stomach is generally regarded as an environment that is not conducive to bacterial colonization. In this study, we examined the possibility that this changes significantly when an ulcer has formed and that colonization of ulcers interferes with the normal healing process. Gastric ulcers were induced by serosal application of acetic acid. The relationship between ulcer healing and bacterial colonization was examined. The effects of antibiotics, induction of Lactobacilluscolonization, and selective colonization with an antibiotic resistant strain of Escherichia coli on ulcer healing were examined. Within 6–12 h of their induction, gastric ulcers were colonized by a variety of bacteria, with gram-negative bacteria predominating. Suppression of colonization with antibiotics resulted in marked acceleration of healing. Induction of Lactobacillus colonization also accelerated ulcer healing. The beneficial effects of antibiotics were reversed through selective colonization with antibiotic-resistant E. coli. Bacterial colonization occurred irrespective of the method used to induce the ulcer. This study demonstrates that colonization of gastric ulcers in rats occurs rapidly and significantly impairs ulcer healing. This effect appeared to be primarily attributable to gram-negative bacteria.

scholarly journals Characterization of the β-lactamase specified by the resistance factor R-1818 in Escherichia coli K12 and other Gram-negative bacteria

1971 ◽  
Vol 123 (4) ◽  
pp. 501-505 ◽  
Author(s):  
J. W. Dale
Keyword(s):  
Escherichia Coli ◽  
Host Species ◽  
Host Bacterium ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
E Coli ◽  
R Factor ◽  
Relationship Of ◽  
The Relationship

1. The amino acid composition of the β-lactamase from E. coli (R-1818) was determined. 2. The R-1818 β-lactamase is inhibited by formaldehyde, hydroxylamine, sodium azide, iodoacetamide, iodine and sodium chloride. 3. The Km values for benzylpenicillin, ampicillin and oxacillin have been determined by using the R-factor enzyme from different host species. The same values were obtained, irrespective of the host bacterium. 4. The molecular weight of the enzyme was found to be 44600, and was the same for all host species. 5. The relationship of R-1818 and R-GN238 β-lactamases is discussed.

Homologous and cross-reacting antibodies in the sera of gnotobiotic rats

1978 ◽  
Vol 24 (4) ◽  
pp. 365-371 ◽  
Author(s):  
Joy C. McLeod ◽  
Edward Balish
Keyword(s):  
Gram Negative Bacteria ◽  
Sprague Dawley ◽  
Gram Positive ◽  
Passive Hemagglutination ◽  
Gram Negative ◽  
E Coli ◽  
Sprague Dawley Rats ◽  
Antibody Titers ◽  
The Relationship ◽  
Reactive Antibody

Sera from Sprague–Dawley rats monoassociated with Clostridium perfringens, C. tertium, C. bifermenlans, Staphylococcus aureus, Escherichia coli, Proteus mirabilis, or Klebsiella pneumoniae for 4 weeks were assayed for homologous and cross-reacting antibodies against antigens on a variety of bacteria. A passive hemagglutination assay, with the antigen(s) consisting of bacteria conjugated to tanned sheep red blood cells, was used to assess antibody titers. Both homologous and cross-reacting antibodies were detected in sera that were collected from the monoassociated animals. Sera from monoassociated rats had agglutinating antibody to genera of bacteria that had not colonized their gastrointestinal tract. Although S. aureus shared some antigens with three species of Clostridium, the relationship was not reciprocal. Sera from rats monoassociated with E. coli, P. mirabilis, or K. pneumoniae had cross-reactive antibody against gram-positive and gram-negative bacteria, but did not have antibodies that could agglutinate H. influenzae type b. Monoassociation with C. perfringens resulted in the production of antibodies against a variety of gram-positive and gram-negative bacteria, but it did not induce cross-reactive antibodies against Corynebacterium diphtheriae, streptococci (groups A, C, and G), or Staphylococcus epidennidis.

scholarly journals Association between the rate of fluoroquinolones-resistant Gram-negative bacteria and antibiotic consumption from China based on 145 tertiary hospitals data in 2014

2019 ◽  
Author(s):  
Ping Yang ◽  
Yunbo Chen ◽  
Saiping Jiang ◽  
Ping Shen ◽  
Xiaoyang Lu ◽  
...  
Keyword(s):  
Antibiotic Consumption ◽  
Resistant Bacteria ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
E Coli ◽  
Annual Consumption ◽  
Tertiary Hospitals ◽  
The Relationship ◽  
Third Generation Cephalosporins ◽  
Consumption Intensity

Abstract This study aimed to investigate the relationship between the rate of fluoroquinolones-resistant (FQR) gram-negative bacteria and antibiotic consumption intensity in 145 tertiary hospitals from China in 2014.Methods A retrospective study using national surveillance data from 2014 was conducted. Data on the annual consumption of each antibiotic, and the rate of FQR gram-negative bacteria, were collected from each participating hospital, and the correlation between antibiotic consumption and FQR rate was simultaneously investigated.Results The overall antibiotic consumption intensity among the hospitals varied between 23.93 and 115.39 defined daily dosages (DDDs) per 100 patient-days (median, 46.30 DDDs per 100 patient-days). Cephalosporins were the most commonly prescribed antibiotics, followed by fluoroquinolones, penicillins, and carbapenems, and the rate of FQR gram-negative bacteria from each hospital varied. The correlation analysis showed significantly relationship between the percentage of FQR E. coli and the consumption of FQs consumption (r=0.308, p<0.01) and levofloxacin (r=0.252, p<0.01). For FQR K. pneumoniae, not only FQs (r=0.291, p<0.01) and levofloxacin (r=0.260, p<0.01) use but also carbapenems (r=0.242, p<0.01) and overall antibiotics (r=0.247, p<0.01) use showed significant correlation. A strong correlation was observed between the resistant proportion of FQR P. aeruginosa and the consumption of all antibiotics (r=0.260, p<0.01), FQs (r=0.319, p<0.01) and levofloxacin (r=0.377, p<0.01). The percentage of levofloxacin-resistant A. baumannii was significantly correlated with the consumption of all antibiotics (r=0.282, p<0.01), third-generation cephalosporins excluding combinations with beta-lactamase inhibitors (r=0.246, p<0.01), FQs (r=0.254, p<0.01) and levofloxacin (r=0.336, p<0.01). However, the correlation of the ciprofloxacin-resistant A. baumannii and the antibiotics consumption was not found.Conclusions A significant relationship was demonstrated between the antibiotic consumption and the rates of FQR gram-negative bacteria. As unreasonable antibiotics usage remains crucial in the proceeding of resistant bacteria selection, our study could greatly promote the avoidance of unnecessary antibiotic usage.

scholarly journals Relationship between Virulence and Resistance among Gram-Negative Bacteria

Antibiotics ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 719
Author(s):  
Virginio Cepas ◽  
Sara M. Soto
Keyword(s):  
Pathogenic Bacteria ◽  
Bacterial Species ◽  
Resistant Bacteria ◽  
Gram Negative Bacteria ◽  
Antibiotic Resistant ◽  
Great Capacity ◽  
Gram Negative ◽  
Points Of View ◽  
The Relationship ◽  
Selection Of

Bacteria present in the human body are innocuous, providing beneficial functions, some of which are necessary for correct body function. However, other bacteria are able to colonize, invade, and cause damage to different tissues, and these are categorised as pathogens. These pathogenic bacteria possess several factors that enable them to be more virulent and cause infection. Bacteria have a great capacity to adapt to different niches and environmental conditions (presence of antibiotics, iron depletion, etc.). Antibiotic pressure has favoured the emergence and spread of antibiotic-resistant bacteria worldwide. Several studies have reported the presence of a relationship (both positive and negative, and both direct and indirect) between antimicrobial resistance and virulence among bacterial pathogens. This review studies the relationship among the most important Gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa) taking into account two points of view: (i) the effect the acquisition of resistance has on virulence, and (ii) co-selection of resistance and virulence. The relationship between resistance and virulence among bacteria depends on the bacterial species, the specific mechanisms of resistance and virulence, the ecological niche, and the host.

Disinfection of Fruits with Activated Water

2019 ◽  
Vol 10 ◽  
pp. 1864-1872
Author(s):  
Prof. Teodora P. Popova
Keyword(s):  
Antimicrobial Activity ◽  
Aqueous Solutions ◽  
Antimicrobial Properties ◽  
The Other ◽  
Gram Negative Bacteria ◽  
High Antimicrobial Activity ◽  
Gram Negative ◽  
E Coli ◽  
Number Of Microorganisms ◽  
Lower Effect

The effect of ionized aqueous solutions (anolytes and catholyte) in the processing of fruits (cherries, morellos, and strawberries) for decontamination has been tested. Freshly prepared analytes and catholyte without the addition of salts were used, as well as stored for 7 months anolytes, prepared with 0.5% NaCl and a combination of 0.5% NaCl and 0.5% Na2CO3. The anolyte prepared with a combination of 0.5% NaCl and 0.5% Na2CO3, as well as the anolyte obtained with 0.5% NaCl, exhibit high antimicrobial activity against the surface microflora of strawberries, cherries, and sour cherries. They inactivate E. coli for 15 minutes. The other species of the fam. Enterobacteriaceae were also affected to the maximum extent, as is the total number of microorganisms, especially in cherries and sour cherries. Even stored for 7 months, they largely retain their antimicrobial properties. Anolyte and catholyte, obtained without the addition of salts, showed a lower effect on the total number of microorganisms, but had a significant effect on Gram-negative bacteria, and especially with regard to the sanitary indicative E. coli.

Structure-Activity Relationship and Antimicrobial Evaluation of N-Phenylpyrazole Curcumin Derivatives

2020 ◽  
Vol 16 (4) ◽  
pp. 481-488
Author(s):  
Heli Sanghvi ◽  
Satyendra Mishra
Keyword(s):  
Antibacterial Activity ◽  
Gram Negative Bacteria ◽  
Pyrazole Derivatives ◽  
Gram Positive ◽  
Gram Negative ◽  
E Coli ◽  
Curcumin Derivatives ◽  
Structure Activity ◽  
Electron Donating Groups ◽  
Derivatives Of

Background: Curcumin, one of the most important pharmacologically significant natural products, has gained significant consideration among scientists for decades since its multipharmacological activities. 1, 3-Dicarbonyl moiety of curcumin was found to be accountable for the rapid degradation of curcumin molecule. The aim of present work is to replace 1, 3-dicarbonyl moiety of curcumin by pyrazole and phenylpyrazole derivatives with a view to improving its stability and to investigate the role of substitution in N-phenylpyrazole curcumin on its antibacterial activity against both Gram-positive as well as Gram-negative bacteria. Methods: Pyrazole derivatives of curcumin were prepared by heating curcumin with phenyhydrazine/ substituted phenyhydrazine derivatives in AcOH. The residue was purified by silica gel column chromatography. Structures of purified compounds were confirmed by 1H NMR and Mass spectroscopy. The synthesized compounds were evaluated for their antibacterial activity by the microdilution broth susceptibility test method against gram positive (S. aureus) and gram negative (E. coli). Results: Effects of substitution in N-phenylpyrazole curcumin derivatives against S. aureus and E. coli were studied. The most active N-(3-Nitrophenylpyrazole) curcumin (12) exhibits twenty-fold more potency against S. aureus (MIC: 10μg/mL)) and N-(2-Fluoroophenylpyrazole) curcumin (5) fivefold more potency against E. coli (MIC; 50 μg/mL) than N-phenylpyrazole curcumin (4). Whereas, a remarkable decline in anti-bacterial activity against S. aureus and E. coli was observed when electron donating groups were incorporated in N-phenylpyrazole curcumin (4). Comparative studies of synthesized compounds suggest the effects of electron withdrawing and electron donating groups on unsubstituted phenylpyrazole curcumin (4). Conclusion: The structure-activity relationship (SAR) results indicated that the electron withdrawing and electron donating at N-phenylpyrazole curcumin played key roles for their bacterial inhibitory effects. The results of the antibacterial evaluation showed that the synthesized pyrazole derivatives of curcumin displayed moderate to very high activity in S. aureus. In conclusion, the series of novel curcumin derivatives were designed, synthesized and tested for their antibacterial activities against S. aureus and E. coli. Among them, N-(3-Nitrophenylpyrazole curcumin; 12) was most active against S. aureus (Gram-positive) and N-(2-Fluoroophenylpyrazole) curcumin (5) against E. coli (Gram-negative) bacteria.

Quality Improvement of the DNA extracted by boiling method in Gram negative bacteria

2017 ◽  
Vol 6 (04) ◽  
pp. 5347 ◽  
Author(s):  
Omar B. Ahmed* ◽  
Anas S. Dablool
Keyword(s):  
Dna Extraction ◽  
Control Method ◽  
Extraction Procedure ◽  
Cost Effective ◽  
High Yield ◽  
Gram Negative Bacteria ◽  
Bacterial Dna ◽  
Gram Negative ◽  
E Coli

Several methods of Deoxyribonucleic acid (DNA) extraction have been applied to extract bacterial DNA. The amount and the quality of the DNA obtained for each one of those methods are variable. The study aimed to evaluate bacterial DNA extraction using conventional boiling method followed by alcohol precipitation. DNA extraction from Gram negative bacilli was extracted and precipitated using boiling method with further precipitation by ethanol. The extraction procedure performed using the boiling method resulted in high DNA yields for both E. coli and K. pneumoniae bacteria in (199.7 and 285.7μg/ml, respectively) which was close to control method (229.3 and 440.3μg/ml). It was concluded that after alcohol precipitation boiling procedure was easy, cost-effective, and applicable for high-yield quality of DNA in Gram-negative bacteria.

scholarly journals Clonal Clusters, Molecular Resistance Mechanisms and Virulence Factors of Gram-Negative Bacteria Isolated from Chronic Wounds in Ghana

Antibiotics ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 339
Author(s):  
Denise Dekker ◽  
Frederik Pankok ◽  
Thorsten Thye ◽  
Stefan Taudien ◽  
Kwabena Oppong ◽  
...  
Keyword(s):  
Molecular Epidemiology ◽  
Virulence Factors ◽  
Iron Uptake ◽  
Chronic Wounds ◽  
Sub Saharan Africa ◽  
Gram Negative Bacteria ◽  
Beta Lactamase ◽  
Secretion Systems ◽  
Gram Negative ◽  
E Coli

Wound infections are common medical problems in sub-Saharan Africa but data on the molecular epidemiology are rare. Within this study we assessed the clonal lineages, resistance genes and virulence factors of Gram-negative bacteria isolated from Ghanaian patients with chronic wounds. From a previous study, 49 Pseudomonas aeruginosa, 21 Klebsiellapneumoniae complex members and 12 Escherichia coli were subjected to whole genome sequencing. Sequence analysis indicated high clonal diversity with only nine P. aeruginosa clusters comprising two strains each and one E. coli cluster comprising three strains with high phylogenetic relationship suggesting nosocomial transmission. Acquired beta-lactamase genes were observed in some isolates next to a broad spectrum of additional genetic resistance determinants. Phenotypical expression of extended-spectrum beta-lactamase activity in the Enterobacterales was associated with blaCTX-M-15 genes, which are frequent in Ghana. Frequently recorded virulence genes comprised genes related to invasion and iron-uptake in E. coli, genes related to adherence, iron-uptake, secretion systems and antiphagocytosis in P. aeruginosa and genes related to adherence, biofilm formation, immune evasion, iron-uptake and secretion systems in K. pneumonia complex. In summary, the study provides a piece in the puzzle of the molecular epidemiology of Gram-negative bacteria in chronic wounds in rural Ghana.

scholarly journals Apomorphine Targets the Pleiotropic Bacterial Regulator Hfq

Antibiotics ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 257
Author(s):  
Florian Turbant ◽  
David Partouche ◽  
Omar El Hamoui ◽  
Sylvain Trépout ◽  
Théa Legoubey ◽  
...  
Keyword(s):  
Small Rnas ◽  
Antibacterial Agents ◽  
Amyloid Fibrils ◽  
Noncoding Rnas ◽  
Amyloid Formation ◽  
Gram Negative Bacteria ◽  
Translation Efficiency ◽  
Gram Negative ◽  
Bacterial Adaptation ◽  
E Coli

Hfq is a bacterial regulator with key roles in gene expression. The protein notably regulates translation efficiency and RNA decay in Gram-negative bacteria, thanks to its binding to small regulatory noncoding RNAs. This property is of primary importance for bacterial adaptation and survival in hosts. Small RNAs and Hfq are, for instance, involved in the response to antibiotics. Previous work has shown that the E. coli Hfq C-terminal region (Hfq-CTR) self-assembles into an amyloid structure. It was also demonstrated that the green tea compound EpiGallo Catechin Gallate (EGCG) binds to Hfq-CTR amyloid fibrils and remodels them into nonamyloid structures. Thus, compounds that target the amyloid region of Hfq may be used as antibacterial agents. Here, we show that another compound that inhibits amyloid formation, apomorphine, may also serve as a new antibacterial. Our results provide an alternative in order to repurpose apomorphine, commonly used in the treatment of Parkinson’s disease, as an antibiotic to block bacterial adaptation to treat infections.

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