scholarly journals Indole Inhibits IncP-1 Conjugation System Mainly Through Promoting korA and korB Expression

2021 ◽  
Vol 12 ◽  
Author(s):  
Rui Xiong ◽  
Yuyang Liu ◽  
Jieying Pu ◽  
Jianping Liu ◽  
Dexiang Zheng ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Inhibitory Concentration ◽  
Acid Resistance ◽  
Donor Strain ◽  
Conjugation System ◽  
Signal Molecule ◽  
E Coli ◽  
Negative Role ◽  
Replication Gene ◽  
Indole Production

Indole works as an interspecies signal molecule to regulate multiple physiological activities, like antibiotic resistance, acid resistance, and virulence. However, the effect of indole on conjugation is unknown. Here, with Escherichia coli SM10λπ as a donor strain that carries a chromosomally integrated conjugative RP4 plasmid, we explored the effect of indole on conjugation of a mobilizable pUCP24T plasmid imparting gentamycin resistance. The results showed that exogenous indole treatment inhibited conjugative transfer of pUCP24T from SM10λπ to recipient strains, Pseudomonas aeruginosa PAO1 and E. coli EC600. Furthermore, raising endogenous indole production through overexpression of TnaA, a tryptophanase, in SM10λπ significantly inhibited both SM10λπ-PAO1 and SM10λπ-EC600 conjugation, whereas deficiency of tnaA reversed the phenotype. Subsequent mechanistic studies revealed that exogenous indole significantly inhibited the expression of mating pair formation gene (trbB) and the DNA transfer and replication gene (trfA), mainly due to the promotion of regulatory genes (korA and korB), and the result was confirmed in tnaA knockout and overexpression strains. Additionally, we found that both extracellular indole production and tnaA expression of SM10λπ were downregulated by ciprofloxacin (CIP). Intriguingly, one-eighth minimum inhibitory concentration of CIP treatment clearly facilitated both SM10λπ-PAO1 and SM10λπ-EC600 conjugation, and indole inhibited CIP-induced conjugation frequency. These data suggest that indole may play a negative role in the process of CIP-induced conjugation. This is the first study to reveal the biological function of indole-inhibiting conjugation and its role in CIP-induced conjugation, which may be developed into a new way of controlling the spread of antibiotic resistance.

scholarly journals Adaptation of Esherichia coli to Antiobiotic Cycling via Single Nucleotide Polymorphisms

2017 ◽  
Vol 14 (1) ◽  
Author(s):  
Samuel Hager ◽  
Ellen Jensen ◽  
Timothy Johnson ◽  
David Mitchell
Keyword(s):  
Escherichia Coli ◽  
Minimum Inhibitory Concentration ◽  
Nalidixic Acid ◽  
Inhibitory Concentration ◽  
Acid Resistance ◽  
Penicillin G ◽  
Single Nucleotide ◽  
E Coli ◽  
Esherichia Coli ◽  
Nalidixic Acid Resistance

Bacteria are quick to adapt and evolve, especially under the effects of selective pressures from chemical antibiotics. In addition, bacteria may develop resistance to antibiotics from multiple classes simultaneously, making their eradication from the human body particularly challenging. This study aims to demonstrate that bacterial multiple-drug resistance can be developed and retained in a laboratory setting. Escherichia coli B was grown in tryptic soy broth in the presence of a small, increasing concentration of streptomycin. This exposure resulted in a strain of E. coli, which had an increased minimum inhibitory concentration (MIC) towards streptomycin, or “resistance.” This resistant strain was then grown in like manner in nalidixic acid and then penicillin G. The result was a strain that became resistant to streptomycin and nalidixic acid, and increasingly resistant to nalidixic acid after penicillin G exposure. Additionally, the bacteria retained resistance to streptomycin and nalidixic acid even after exposure to those chemicals ceased. Genome sequencing and comparison to E. coli B reference strain REL606 revealed the emergence of point mutations with each exposure to an antibiotic. Of particular interest is a mutation associated with the appearance of nalidixic acid resistance. Base pair 4,553,488 was changed from adenine to guanine, resulting in a change from aspartate to glycine in the protein helicase. Previous studies have not indicated mutations to this locus as nalidixic acid resistance conferring. Thus, this mutation may be a novel mutation conferring E. coli B nalidixic acid resistance. Since the region of the mutated helicase is functionally undefined, a mechanism is not apparent. Further research needs to be done to confirm this hypothesis and illuminate a mechanism. KEYWORDS: Bacteria; Escherichia coli; Evolution; Antibiotic Resistance; Nalidixic Acid; Streptomycin; Point Mutation; Single-nucleotide Polymorphism; Helicase; Minimum Inhibitory Concentration

scholarly journals In Vitro Investigation of the Antibacterial Effect of Silver Nanoparticles on ESBL-producing E. coli and Klebsiella spp. Isolated from Pet Animals

2020 ◽  
pp. 514-524
Author(s):  
Omnia A Khalil ◽  
Mona I Enbaawy ◽  
Taher Salah ◽  
Hossam Mahmoud ◽  
Eman Ragab
Keyword(s):  
Silver Nanoparticles ◽  
Antibiotic Resistance ◽  
Resistance Genes ◽  
Inhibitory Concentration ◽  
Minimum Bactericidal Concentration ◽  
Antibacterial Effect ◽  
Antibiotic Resistance Genes ◽  
E Coli ◽  
Klebsiella Spp

Despite the presence of modern antibacterial drugs, bacterial infections are still a major threatening problem due to the enormous increase in multi-drug-resistant bacteria. Nanoparticles have been extensively used as an applicable and safe alternative to antibiotics. The present study aimed to explore the inhibitory effect of silver nanoparticles on Extended Spectrum Beta lactamase (ESBL) producing E. coli and Klebsiella spp. in vitro as well as their effect on the expression of antibiotic resistance genes. Different samples (i.e., wound swabs, Fecal swabs, and urine samples) were collected from dogs and cats. Phenotypic and molecular identification, antibiotic susceptibility testing, and double-disk synergy test were carried out for the identification of ESBL producing E. coli and Klebsiella spp. Silver nanoparticles were tested for their in vitro antibacterial potential and there were reports of their minimum inhibitory concentration and minimum bactericidal concentration. Moreover, the effect of silver nanoparticles on the expression of antibiotic resistance genes (i.e., blaTEM, blaSHV, and blaCTX) was assessed as well as their effect on the structural integrity of the bacterial cells using Scanning Electron Microscope (SEM). Results revealed that 23 isolates (19.16%) (E. coli=17, Klebsiella spp.=6) were confirmed as ESBL producing. Silver nanoparticles indicated a promising antibacterial effect where the minimum inhibitory concentration of AgNPs for ESBL producing E. coli was measured as 0.31 mg/ml, and 0.62 mg/ml for ESBL-producing Klebsiella spp., while the minimum bactericidal concentration of ESBL-producing E. coli and Klebsiella spp. was reported as 0.15 mg/ml and 0.3 mg/ml, respectively. Consequently, the expression of antibiotic resistance genes was downregulated in both bacteria species and there was a noticeable toxic effect of AgNPs on E. coli and Klebsiella spp. cells which was investigated using SEM. It can be concluded that silver nanoparticles have a promising antibacterial activity and could be considered an applicable alternative for the control of ESBL producing bacteria.

scholarly journals Identification of IbeR as a Stationary-Phase Regulator in MeningiticEscherichia coliK1 that Carries a Loss-of-Function Mutation inrpoS

2009 ◽  
Vol 2009 ◽  
pp. 1-13 ◽  
Author(s):  
Feng Chi ◽  
Ying Wang ◽  
Timothy K. Gallaher ◽  
Chun-Hua Wu ◽  
Ambrose Jong ◽  
...  
Keyword(s):  
Stationary Phase ◽  
Stress Resistance ◽  
Parent Strain ◽  
Regulatory Gene ◽  
Loss Of Function ◽  
Signal Molecule ◽  
Two Dimensional Gel Electrophoresis ◽  
E Coli ◽  
Survival Studies ◽  
Indole Production

IbeRis a regulator present in meningiticEscherichia colistrain E44 that carries a loss-of-function mutation in the stationary-phase (SP) regulatory generpoS. In order to determine whether IbeR is an SP regulator in E44, two-dimensional gel electrophoresis and LC-MS were used to compare the proteomes of a noninvasive ibeR deletion mutant BR2 and its parent strain E44 in the SP. Four up-regulated (TufB, GapA, OmpA, AhpC) and three down-regulated (LpdA, TnaA, OpmC) proteins in BR2 were identified when compared to E44. All these proteins contribute to energy metabolism or stress resistance, which is related to SP regulation. One of the down-regulated proteins, tryptophanase (TnaA), which is regulated by RpoS in otherE. colistrains, is associated with SP regulation via production of a signal molecule indole. Our studies demonstrated that TnaA was required for E44 invasion, and that indole was able to restore the noninvasive phenotype of thetnaAmutant. The production of indole was significantly reduced in BR2, indicating thatibeRis required for the indole production viatnaA. Survival studies under different stress conditions indicated that IbeR contributed to bacteria stress resistance in the SP. Taken together, IbeR is a novel regulator contributing to the SP regulation.

scholarly journals Transfer of Antibiotic Resistance Plasmid from Commensal E. coli Towards Human Intestinal Microbiota in the M-SHIME: Effect of E. coli dosis, Human Individual and Antibiotic Use

Life ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 192
Author(s):  
Ellen Lambrecht ◽  
Els Van Coillie ◽  
Nico Boon ◽  
Marc Heyndrickx ◽  
Tom Van de Wiele
Keyword(s):  
Antibiotic Resistance ◽  
Intestinal Microbiota ◽  
Resistant Bacteria ◽  
Donor Strain ◽  
Antibiotic Resistant ◽  
E Coli ◽  
Resistance Plasmid ◽  
Human Intestinal Microbiota ◽  
Resistance Transfer ◽  
Human Individual

Along with (in) direct contact with animals and a contaminated environment, humans are exposed to antibiotic-resistant bacteria by consumption of food. The implications of ingesting antibiotic-resistant commensal bacteria are unknown, as dose-response data on resistance transfer and spreading in our gut is lacking. In this study, transfer of a resistance plasmid (IncF), harbouring several antibiotic resistance genes, from a commensal E. coli strain towards human intestinal microbiota was assessed using a Mucosal Simulator of the Human Intestinal Ecosystem (M-SHIME). More specifically, the effect of the initial E. coli plasmid donor concentration (105 and 107 CFU/meal), antibiotic treatment (cefotaxime) and human individual (n = 6) on plasmid transfer towards lumen coliforms and anaerobes was determined. Transfer of the resistance plasmid to luminal coliforms and anaerobes was observed shortly after the donor strain arrived in the colon and was independent of the ingested dose. Transfer occurred in all six simulated colons and despite their unique microbial community composition, no differences could be detected in antibiotic resistance transfer rates between the simulated human colons. After 72 h, resistant coliform transconjugants levels ranged from 7.6 × 104 to 7.9 × 106 CFUcefotaxime resistant/Ml colon lumen. Presence of the resistance plasmid was confirmed and quantified by PCR and qPCR. Cefotaxime treatment led to a significant reduction (85%) in resistant coliforms, however no significant effect on the total number of cultivable coliforms and anaerobes was observed.

Relationship of antibiotic resistance to results of treatment in sepsis patients in Hue Central Hospital 2017 – 2018

2019 ◽  
pp. 48-54
Author(s):  
Duy Binh Nguyen ◽  
Trung Tien Phan ◽  
Trong Hanh Hoang ◽  
Van Tuan Mai ◽  
Xuan Chuong Tran
Keyword(s):  
Antibiotic Resistance ◽  
Bacterial Infection ◽  
Resistant Bacteria ◽  
Central Hospital ◽  
International Consensus ◽  
Antibiotic Resistant ◽  
E Coli ◽  
Results Of Treatment ◽  
Amoxicillin Clavulanic Acid ◽  
Relationship Of

Sepsis is a serious bacterial infection. The main treatment is using antibiotics. However, the rate of antibiotic resistance is very high and this resistance is related to the outcome of treatment. Objectives: To evaluate the situation of antibiotic resistance of some isolated bacteria in sepsis patients treated at Hue Central Hospital; to evaluate the relationship of antibiotic resistance to the treatment results in patients with sepsis. Subjects and methods: prospective study of 60 sepsis patients diagnosed according to the criteria of the 3rd International Consensus-Sepsis 3 and its susceptibility patterns from April 2017 to August 2018. Results and Conclusions: The current agents of sepsis are mainly S. suis, Burkhoderiae spp. and E. coli. E. coli is resistant to cephalosporins 3rd, 4th generation and quinolone group is over 75%; resistance to imipenem 11.1%; the ESBL rate is 60%. S. suis resistant to ampicilline 11.1%; no resistance has been recorded to ceftriaxone and vancomycine. Resistance of Burkholderiae spp. to cefepime and amoxicillin/clavulanic acid was 42.9% and 55.6%, resistant to imipenem and meropenem is 20%, resistance to ceftazidime was not recorded. The deaths were mostly dued to E. coli and K. pneumoniae. The mortality for patients infected with antibiotic-resistant bacteria are higher than for sensitive groups. Key words: Sepsis, bacterial infection, antibiotics

The Characterization of Antibiotic Resistance of Bacterial Isolates from Intensive Care Unit Patient Samples in a University Affiliated Hospital in Romania

2019 ◽  
Vol 70 (5) ◽  
pp. 1778-1783
Author(s):  
Andreea-Loredana Golli ◽  
Floarea Mimi Nitu ◽  
Maria Balasoiu ◽  
Marina Alina Lungu ◽  
Cristiana Cerasella Dragomirescu ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Antibiotic Resistance ◽  
Bacterial Pathogens ◽  
Resistance Rate ◽  
Resistance Pattern ◽  
Bacterial Isolates ◽  
E Coli ◽  
Acinetobacter Spp ◽  
Almost All ◽  
Klebsiella Spp

To determine the resistance pattern of bacterial pathogens involved in infections of the patients aged between 18-64 years, admitted in a ICU from a 1518-bed university-affiliated hospital. A retrospective study of bacterial pathogens was carried out on 351 patients aged between 18-64 years admitted to the ICU, from January to December 2017. In this study there were analysed 469 samples from 351 patients (18-64 years). A total of 566 bacterial isolates were obtained, of which 120 strains of Klebsiella spp. (35.39%%), followed by Nonfermenting Gram negative bacilli, other than Pseudomonas and Acinetobacter (NFB) (75- 22.12%), Acinetobacter spp. (53 - 15.63%), Pseudomonas aeruginosa and Proteus (51 - 15.04%), and Escherichia coli (49 - 14.45%). The most common isolates were from respiratory tract (394 isolates � 69.61%). High rates of MDR were found for Pseudomonas aeruginosa (64.70%), MRSA (62.65%) and Klebsiella spp. (53.33%), while almost all of the isolated NFB strains were MDR (97.33%). There was statistic difference between the drug resistance rate of Klebsiella and E. coli strains to ceftazidime and ceftriaxone (p[0.001), cefuroxime (p[0.01) and to cefepime (p[0.01). The study revealed an alarming pattern of antibiotic resistance in the majority of ICU isolates.

Surveillance of Antibiotic Resistance Among Enterobacteriaceae Strains Isolated in an Infectious Diseases Hospital from Romania

2018 ◽  
Vol 69 (5) ◽  
pp. 1240-1243
Author(s):  
Manuela Arbune ◽  
Mioara Decusara ◽  
Luana Andreea Macovei ◽  
Aurelia Romila ◽  
Alina Viorica Iancu ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Infectious Diseases ◽  
Salmonella Spp ◽  
Resistance Level ◽  
E Coli ◽  
Bacterial Genus ◽  
Antibiotic Resistance Profile ◽  
Carbapenem Resistant ◽  
Invasive Infections ◽  
Klebsiella Spp

The aim of the present study was to characterize the antibiotic resistance profile of enterobacteriaceae strains isolated in Infectious Diseases Hospital Galati, Romania, during 2016, in order to guide the local antibiotic stewardship strategy. There are 597 biological samples with positive cultures for enterobacteriaceae, related to invasive and non-invasive infections. The main bacterial genus were E. coli 62%, Klebsiella spp 15%, Proteus spp 11% and Salmonella spp 6%. Over a half of isolated strains have one or more antibiotic resistance. The resistance level depends on bacterial genus, with highest level found among the rare isolates: Enterobacter spp, Citrobacter spp, Morganella spp and Serratia spp. The rate of MDR was 17.,6% for E. coli, 40.9% for Klebsiella spp and 50.7% for Proteus spp. while the rate of strains producing Extended Spectrum of Beta Lactamase are 7.2% for E. coli, 28.4% for Klebsiella spp and 12.3% for Proteus spp. The carbapenem resistant strains were found in 1.1% cases.

In Vitro Antibacterial activity of ethanolic extract of Myrsine africana against laboratory Strains of Pathogenic Organisms

2016 ◽  
Vol 5 (04) ◽  
pp. 4512
Author(s):  
Jackie K. Obey ◽  
Anthoney Swamy T* ◽  
Lasiti Timothy ◽  
Makani Rachel
Keyword(s):  
Antibacterial Activity ◽  
Minimum Inhibitory Concentration ◽  
Inhibitory Concentration ◽  
Ethanolic Extract ◽  
Ethanol Extract ◽  
E Coli ◽  
Zones Of Inhibition ◽  
In Vitro Antibacterial Activity ◽  
Myrsine Africana

The determination of the antibacterial activity (zone of inhibition) and minimum inhibitory concentration of medicinal plants a crucial step in drug development. In this study, the antibacterial activity and minimum inhibitory concentration of the ethanol extract of Myrsine africana were determined for Escherichia coli, Bacillus cereus, Staphylococcus epidermidis and Streptococcus pneumoniae. The zones of inhibition (mm±S.E) of 500mg/ml of M. africana ethanol extract were 22.00± 0.00 for E. coli,20.33 ±0.33 for B. cereus,25.00± 0.00 for S. epidermidis and 18. 17±0.17 for S. pneumoniae. The minimum inhibitory concentration(MIC) is the minimum dose required to inhibit growth a microorganism. Upon further double dilution of the 500mg/ml of M. africana extract, MIC was obtained for each organism. The MIC for E. coli, B. cereus, S. epidermidis and S. pneumoniae were 7.81mg/ml, 7.81mg/ml, 15.63mg/ml and 15.63mg/ml respectively. Crude extracts are considered active when they inhibit microorganisms with zones of inhibition of 8mm and above. Therefore, this study has shown that the ethanol extract of M. africana can control the growth of the four organisms tested.

scholarly journals A NEW MAP LOCATION FOR THE ilvB LOCUS OF ESCHERICHIA COLI

Genetics ◽  
1980 ◽  
Vol 96 (1) ◽  
pp. 59-77
Author(s):  
Thomas C Newman ◽  
Mark Levinthal
Keyword(s):  
Escherichia Coli ◽  
Structural Gene ◽  
Acetolactate Synthase ◽  
Deletion Mapping ◽  
Donor Strain ◽  
E Coli ◽  
Linkage Of Genes ◽  
Map Location ◽  
New Alleles

ABSTRACT We isolated, in E. coli K12, new alleles of the ilvB locus, the structural gene for acetolactate synthase isoenzyme I, and showed them to map at or near the ilvB619 site. The map position of the ilvB locus was redetermined because plasmids containing the ilvC-cya portion of the chromosome did not complement mutations at the ilvB locus. Furthermore, diploids for the ilvEDAC genes formed with these plasmids in an ilvHI background facilitated the isolation of the new ilvB alleles. The ilvB locus was remapped and found to be located at 81.5 minutes, between the uhp and dnaA loci. This location was determined by two- and three-point transductional crosses, deletion mapping and complementation with newly isolated plasmids. One of the new alleles of the ilvB gene is a mu-1 insertion. When present in the donor strain, this allele interferes with the linkage of genes flanking the mu-1 insertion, as well as the linkage of genes to either side of the mu-1 insertion.

scholarly journals Granulibacter bethesdensis, a Pathogen from Patients with Chronic Granulomatous Disease, Produces a Penta-Acylated Hypostimulatory Glycero-d-talo-oct-2-ulosonic Acid–Lipid A Glycolipid (Ko-Lipid A)

2021 ◽  
Vol 22 (7) ◽  
pp. 3303
Author(s):  
Artur Muszyński ◽  
Kol A. Zarember ◽  
Christian Heiss ◽  
Joseph Shiloach ◽  
Lars J. Berg ◽  
...  
Keyword(s):  
Chronic Granulomatous Disease ◽  
Human Blood ◽  
Lipid A ◽  
Acid Resistance ◽  
Strong Acid ◽  
Granulomatous Disease ◽  
E Coli ◽  
Phagocyte Nadph Oxidase ◽  
Acyl Chains ◽  
Ulosonic Acid

Granulibacter bethesdensis can infect patients with chronic granulomatous disease, an immunodeficiency caused by reduced phagocyte NADPH oxidase function. Intact G. bethesdensis (Gb) is hypostimulatory compared to Escherichia coli, i.e., cytokine production in human blood requires 10–100 times more G. bethesdensis CFU/mL than E. coli. To better understand the pathogenicity of G. bethesdensis, we isolated its lipopolysaccharide (GbLPS) and characterized its lipid A. Unlike with typical Enterobacteriaceae, the release of presumptive Gb lipid A from its LPS required a strong acid. NMR and mass spectrometry demonstrated that the carbohydrate portion of the isolated glycolipid consists of α-Manp-(1→4)-β-GlcpN3N-(1→6)-α-GlcpN-(1⇿1)-α-GlcpA tetra-saccharide substituted with five acyl chains: the amide-linked N-3′ 14:0(3-OH), N-2′ 16:0(3-O16:0), and N-2 18:0(3-OH) and the ester-linked O-3 14:0(3-OH) and 16:0. The identification of glycero-d-talo-oct-2-ulosonic acid (Ko) as the first constituent of the core region of the LPS that is covalently attached to GlcpN3N of the lipid backbone may account for the acid resistance of GbLPS. In addition, the presence of Ko and only five acyl chains may explain the >10-fold lower proinflammatory potency of GbKo–lipidA compared to E. coli lipid A, as measured by cytokine induction in human blood. These unusual structural properties of the G.bethesdensis Ko–lipid A glycolipid likely contribute to immune evasion during pathogenesis and resistance to antimicrobial peptides.

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