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 A novel, double mutation in DNA gyrase A of Escherichia coli conferring resistance to quinolone antibiotics.

1997 ◽  
Vol 41 (1) ◽  
pp. 85-90 ◽  
Author(s):  
Q C Truong ◽  
J C Nguyen Van ◽  
D Shlaes ◽  
L Gutmann ◽  
N J Moreau
Keyword(s):  
Escherichia Coli ◽  
Nalidixic Acid ◽  
Acid Resistance ◽  
Gyra Gene ◽  
Double Mutation ◽  
E Coli ◽  
Quinolone Antibiotics ◽  
Gyrase A ◽  
Level Resistance ◽  
Nalidixic Acid Resistance

A spontaneous Escherichia coli mutant, named Q3, resistant to nalidixic acid was obtained from a previously described clinical isolate of E. coli, Q2, resistant to fluoroquinolones but susceptible to nalidixic acid (E. Cambau, F. Bordon, E. Collatz, and L. Gutmann, Antimicrob. Agents Chemother. 37:1247-1252, 1993). Q3 harbored the mutation Asp82Gly in addition to the Gly81Asp mutation of Q2. The different mutations leading to Gly81Asp, Asp82Gly, and Gly81AspAsp82Gly were introduced into the gyrA gene harbored on plasmid pJSW102, and the resulting plasmids were introduced into E. coli KNK453 (gyrAts) by transformation. The presence of Asp82Gly or Gly81Asp alone led to a low-level resistance to fluoroquinolones but not to nalidixic acid resistance. When both mutations were present, resistance to both nalidixic acid and fluoroquinolones was expressed. Purified gyrases of the different mutants showed similar rates of supercoiling. Dominance of the various gyrA mutant alleles harbored on plasmids was examined. The susceptibility to quinolones associated with wild-type gyrA was always dominant. The susceptibility to nalidixic acid expressed by the Gly81Asp mutant was dominant, while that expressed by the Asp82Gly mutant was recessive. From these results, we hypothesize that some amino acids within the quinolone resistance-determining region of gyrase A are more important for the association of subunits rather than for the activity of the holoenzyme.

scholarly journals Transcriptome analysis of Escherichia coli K1 after therapy with hesperidin conjugated with silver nanoparticles

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Abdulkader Masri ◽  
Naveed Ahmed Khan ◽  
Muhammad Zarul Hanifah Md Zoqratt ◽  
Qasim Ayub ◽  
Ayaz Anwar ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Silver Nanoparticles ◽  
Minimum Inhibitory Concentration ◽  
Inhibitory Concentration ◽  
Neonatal Meningitis ◽  
E Coli ◽  
Drug Candidates ◽  
Metabolic Genes ◽  
Genetic Mechanisms ◽  
Cell Stress Response

Abstract Backgrounds Escherichia coli K1 causes neonatal meningitis. Transcriptome studies are indispensable to comprehend the pathology and biology of these bacteria. Recently, we showed that nanoparticles loaded with Hesperidin are potential novel antibacterial agents against E. coli K1. Here, bacteria were treated with and without Hesperidin conjugated with silver nanoparticles, and silver alone, and 50% minimum inhibitory concentration was determined. Differential gene expression analysis using RNA-seq, was performed using Degust software and a set of genes involved in cell stress response and metabolism were selected for the study. Results 50% minimum inhibitory concentration with silver-conjugated Hesperidin was achieved with 0.5 μg/ml of Hesperidin conjugated with silver nanoparticles at 1 h. Differential genetic analysis revealed the expression of 122 genes (≥ 2-log FC, P< 0.01) in both E. coli K1 treated with Hesperidin conjugated silver nanoparticles and E. coli K1 treated with silver alone, compared to untreated E. coli K1. Of note, the expression levels of cation efflux genes (cusA and copA) and translocation of ions, across the membrane genes (rsxB) were found to increase 2.6, 3.1, and 3.3- log FC, respectively. Significant regulation was observed for metabolic genes and several genes involved in the coordination of flagella. Conclusions The antibacterial mechanism of nanoparticles maybe due to disruption of the cell membrane, oxidative stress, and metabolism in E. coli K1. Further studies will lead to a better understanding of the genetic mechanisms underlying treatment with nanoparticles and identification of much needed novel antimicrobial drug candidates.

scholarly journals Susceptibility to patterns of ciprofloxacin among nalidixic acid-resistant Salmonella isolates collected in Banepa, Nepal from enteric fever patients

2016 ◽  
Vol 89 (2) ◽  
Author(s):  
Girija Roka ◽  
Subash Pandaya ◽  
Md. Reyad-ul Ferdous ◽  
Manson Pandey ◽  
Naba Raj Pokhrel ◽  
...  
Keyword(s):  
Nalidixic Acid ◽  
Salmonella Enterica ◽  
Enteric Fever ◽  
Inhibitory Concentration ◽  
Acid Resistance ◽  
Dilution Method ◽  
Disc Diffusion ◽  
Antimicrobial Sensitivity ◽  
Broth Dilution ◽  
Nalidixic Acid Resistance

The present study determined the susceptibility to ciprofloxacin of nalidixic acid resistant <em>Salmonella</em> (NARS) isolated from enteric fever patients at Scheer Memorial Hospital, Banepa, Nepal, from June 2012 to December 2012. The antimicrobial sensitivity to nalidixic acid and ciprofloxacin was determined using modified Kirby-Bauer disc diffusion and broth dilution method according to the guidelines of the Clinical and Laboratory Standard Institute. <em>Salmonella</em> was isolated from 34 out of 992 (3.43%) blood cultures collected during the study period, and 10 (29.4%) isolates were identified as <em>Salmonella enterica</em> serotype Typhi, while 24 (70.6%) were identified as <em>Salmonella enterica</em> serotype Paratyphi. Out of the total isolates, 31 (91.2%) were nalidixic acid-resistant <em>Salmonella</em> (NARS). Among NARS, the minimum inhibitory concentration values for ciprofloxacin ranged from 0.25 to 2 mg/L and were constantly higher than those shown by the nalidixic acid-susceptible <em>Salmonella</em>. Therefore, in typhoid <em>Salmonella</em> nalidixic acid resistance may be the indicator of decreased susceptibility to ciprofloxacin.

Serum Inhibitory and Bactericidal Activity of Ciprofloxacin following Intravenous Administration

DICP ◽  
1989 ◽  
Vol 23 (6) ◽  
pp. 456-460
Author(s):  
Michael N. Dudley ◽  
Hilary D. Mandler ◽  
Kenneth H. Mayer ◽  
Stephen H. Zinner
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Pseudomonas Aeruginosa ◽  
Minimum Inhibitory Concentration ◽  
Bactericidal Activity ◽  
Resistant Strain ◽  
Inhibitory Concentration ◽  
Minimum Bactericidal Concentration ◽  
E Coli ◽  
Dose Levels

Serum inhibitory and bactericidal titers were measured in nine healthy volunteers following single iv doses of ciprofloxacin 100, 150, and 200 mg. The median peak serum bactericidal titer (5 minutes following completion of a 30-minute infusion) against two highly susceptible strains of Escherichia coli ranged between 1:64 and 1:1024 and titers exceeded 1:8 for six hours for all dose levels. The bactericidal titers against two strains of Pseudomonas aeruginosa and a methicillin-resistant strain of Staphylococcus aureus were considerably lower, the median peak being 1:2 at all dose levels. Measured inhibitory and bactericidal titers at five minutes and one hour postinfusion were significantly greater than those predicted (measured serum ciprofloxacin concentration to minimum inhibitory concentration [MIC] or minimum bactericidal concentration [MBC]) for only one strain of E. coli. Intravenous doses of ciprofloxacin 100–200 mg produce high and sustained serum bactericidal titers against highly susceptible bacteria; considerably lower levels of activity are seen against bacteria having higher MICs and MBCs but still considered susceptible to the drug.

scholarly journals Escherichia coli from community-acquired urinary tract infections resistant to fluoroquinolones and extended-spectrum beta-lactams

2007 ◽  
Vol 1 (03) ◽  
pp. 257-262 ◽  
Author(s):  
Samuel Kariuki ◽  
Gunturu Revathi ◽  
John Corkill ◽  
John Kiiru ◽  
Joyce Mwituria ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Urinary Tract ◽  
Nalidixic Acid ◽  
Urinary Tract Infections ◽  
Acid Resistance ◽  
Beta Lactam ◽  
E Coli ◽  
Extended Spectrum ◽  
Tract Infections ◽  
Multiple Drugs

Background: Uropathogenic Escherichia coli are increasingly becoming resistant to flouroquinolones and to other commonly available antimicrobials. We sought to investigate the genetic basis for fluoroquinolone and extended spectrum beta-lactam (ESBL) resistance in 17 fluoroquinolone-resistant (MIC of levofloxacin and ciprofloxacin >32 μg/ml) E. coli isolated from patients with urinary tract infections (UTIs). Methods: We applied PCR and Pulsed Field Gel Electrophoresis (PFGE) to characterize resistance genes and to determine clonal relatedness of strains, respectively. Results: Twelve of the 17 E. coli were resistant to multiple drugs, including ampicillin, co-amoxyclav, cefotaxime, ceftriaxone, ceftazidime and gentamicin and nalidixic acid and produced plasmid-mediated CTX-M-15 type ESBLs and CMY-2 AmpC type enzymes. The other 5 E. coli that were non-ESBL-producing were multiply resistant to ampicillin, nitrofurantoin, cefoxitin, nalidixic acid. Resistance to fluoroquinolones resulted from a combination of the presence of qnrA, qnrB, ciprofloxacin acetylating enzyme designated aac(6’)-1b-cr, and mutations in the two amino acid substitutions; 83 Serine (TCG) to Leucine (TTG) and 87 Aspartic acid (GAC) to Asparagine (AAC). Conclusion: Antibiogram patterns and PFGE of E. coli showed that these were community acquired UTI caused by pockets of clonally-related and some discreet strain types. Plasmid-mediated CTX-M-15 beta-lactamases and CMY-2 AmpC enzymes and fluoroquinolone resistant E. coli are becoming increasingly prevalent in hospitals in Kenya, posing a major challenge in the management of UTIs.

scholarly journals Heterogeneous Absorption of Antimicrobial Peptide LL37 inEscherichia coliCells Enhances Population Survivability

2018 ◽  
Author(s):  
Mehdi Snoussi ◽  
John Paul Talledo ◽  
Nathan-Alexander Del Rosario ◽  
Bae-Yeun Ha ◽  
Andrej Košmrlj ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Mathematical Model ◽  
Minimum Inhibitory Concentration ◽  
Cell Density ◽  
Inhibitory Concentration ◽  
Single Cell Level ◽  
Cell Level ◽  
E Coli ◽  
Rapid Absorption ◽  
Growing Population

AbstractAntimicrobial peptides (AMPs) are broad spectrum antibiotics that selectively target bacteria. Here we investigate the activity of human AMP LL37 againstEscherichia coliby integrating quantitative, population and single-cell level experiments with theoretical modeling. Our data indicate an unexpected, rapid absorption and retention of a large number of LL37 byE. colicells upon the inhibition of their growth, which increases the chance of survival for the rest of population. Cultures with high-enough cell density exhibit two distinct subpopulations: a non-growing population that absorb peptides and a growing population that survive owing to the sequestration of the AMPs by others. A mathematical model based on this binary picture reproduces the rather surprising behaviors ofE. colicultures in the presence of LL37, including the increase of the minimum inhibitory concentration with cell density (even in dilute cultures) and the extensive lag in growth introduced by sub-lethal dosages of LL37.

scholarly journals Determination of the carbapenem resistance in Escherichia coli isolated from samples obtained from Shahrekord hospitals and determination of their minimum inhibitory concentration

2019 ◽  
Vol 21 (6) ◽  
pp. 280-283
Author(s):  
Farshad Kakian ◽  
Behnam Zamanzad ◽  
Abolfazle Gholipour ◽  
Kiarash Zamanzad
Keyword(s):  
Escherichia Coli ◽  
Minimum Inhibitory Concentration ◽  
Inhibitory Concentration ◽  
Carbapenem Resistance ◽  
Test Strip ◽  
Major Step ◽  
Accurate Identification ◽  
E Coli ◽  
Tract Infections

Background and aims: Carbapenems are the final-line treatments for multidrug-resistant, gram-negative infections. The patterns of resistance to carbapenems among hospital bacterial pathogens vary widely across different hospitals in a country. Considering that Escherichia coli is one of the most important causes of nosocomial infections, it is essential to study its drug resistance. Methods: In this descriptive-analytical study, a total of 80 samples of E. coli isolated from inpatients with urinary tract infections (UTIs) were collected in different wards (i.e., women, urology, infectious, and ICU) of Shahrekord hospitals. After the diagnosis and confirmation of bacteria by standard bacteriological methods, their sensitivity to imipenem and meropenem was investigated by the antibiogram (diskdiffusion) method. Then, the minimum inhibitory concentration (MIC) was determined by the E-test strip according to the Clinical and Laboratory Standards Institute (CLSI) standard. Results: In this study, resistance to meropenem and imipenem by antibiogram (disc diffusion) was observed in 21 (25.26%) and 20 (25%) of the isolates, respectively. Twenty isolates had MIC ≥4 μg/mL for meropenem, 13 isolates demonstrated MIC≥4 μg/mL for imipenem, and 14 isolates had 1≤MIC<4 μg/mL and were semi-sensitive. Conclusion: In general, E. coli had significant resistance to carbapenems. Therefore, rapid and accurate identification of these strains can be a major step to the treatment and control of these strains and prevention of the spread of the resistance.

scholarly journals AKTIVITAS ANTIBAKTERI EKSTRAK BIJI JERUK SIAM (Citrus reticulata) PADA BAKTERI Escherichia coli

2020 ◽  
Vol 7 (2) ◽  
pp. 289-295
Author(s):  
Mohammad Arfi Setiawan ◽  
Mita Dewi Retnoningrum ◽  
Febriyandhi Yahya ◽  
Resa Ragil Andika ◽  
Dyan Hatining Ayu Sudarni
Keyword(s):  
Escherichia Coli ◽  
Antibacterial Activity ◽  
Minimum Inhibitory Concentration ◽  
Inhibitory Concentration ◽  
Seed Extract ◽  
Nutrient Agar ◽  
Citrus Reticulata ◽  
E Coli ◽  
Mic Minimum Inhibitory Concentration ◽  
Paper Disc

Antibacterial Activity of Citrus seed (Citrus reticulata) Extract on Escherichia coli Indonesian agriculture provides a resource of medicinal plants whose potential needs to be explored in order to benefit society. One of them is the use of Siam orange seeds (Citrus reticulata) which has the potential for the production of antibacterial compounds. This study aims to test the antibacterial activity of the ethanol and n-hexane extract of orange seeds. The extract was obtained through maceration techniques using ethanol and n-hexane as solvents. The antibacterial activity test of orange seeds against Escherichia coli used the paper disc diffusion method with nutrient agar (NA) media. The concentration of orange seed extract for the determination of MIC (Minimum Inhibitory Concentration) was 0.5, 2, 8, 10, 20 mg mL-1. The results showed that the ethanol and n-hexane extract of orange seeds had antibacterial activity against E. coli. However, the ethanol extract had a higher antibacterial effect than the n-hexane orange seed extract. From the results of this study, it is hoped that the waste of orange seeds will provide beneficial contribution for pharmaceutical development. Pertanian Indonesia memiliki sumber tanaman obat yang perlu digali potensinya agar bermanfaat bagi masyarakat. Salah satunya pemanfaatan biji jeruk siam (Citrus reticulata) yang berpotensi menghasilkan senyawa antibakteri. Penelitian ini bertujuan untuk menguji aktivitas antibakteri ekstrak etanol dan n-heksana biji jeruk. Ekstrak diperoleh melalui teknik maserasi menggunakan pelarut etanol dan n-heksana. Uji aktivitas antibakteri biji jeruk terhadap Escherichia coli menggunakan metode difusi paper disc dengan media nutrient agar (NA). Konsentrasi ekstrak biji jeruk untuk penentuan MIC (Minimum Inhibitory Concentration) adalah 0,5, 2, 8, 10, 20 mg mL-1. Hasil penelitian menunjukkan bahwa ekstrak etanol dan n-heksana biji jeruk memiliki aktivitas antibakteri terhadap E. coli. Namun, ekstrak etanol memiliki efek antibakteri yang lebih tinggi dibandingkan ekstrak biji jeruk n-heksana. Dari hasil penelitian ini, limbah biji jeruk diharapkan dapat memberikan kontribusi bermanfaat bagi pengembangan farmasi.

Sign in / Sign up

Export Citation Format

Share Document