scholarly journals Gene Expression during Survival ofEscherichia coliO157:H7 in Soil and Water

2011 ◽  
Vol 2011 ◽  
pp. 1-12 ◽  
Author(s):  
Ashley D. Duffitt ◽  
Robert T. Reber ◽  
Andrew Whipple ◽  
Christian Chauret
Keyword(s):  
Antibiotic Resistance ◽  
Ribosomal Proteins ◽  
Dna Microarrays ◽  
Stream Water ◽  
Expression Patterns ◽  
Luria Broth ◽  
Sterile Soil ◽  
Experimental Conditions ◽  
E Coli

Thein vitrosurvival ofEscherichia coliO157:H7 at15∘Cunder two experimental conditions (sterile soil and sterile natural water) was examined. DNA microarrays of the entire set ofE. coliO157:H7 genes were used to measure the genomic expression patterns after 14 days. Although the populations declined, someE. coliO157:H7 cells survived in sterile stream water up to 234 days and in sterile soil for up to 179 days. Cells incubated in soil microcosms for 14 days expressed genes for antibiotic resistance, biosynthesis, DNA replication and modification, metabolism, phages, transposons, plasmids, pathogenesis and virulence, antibiotic resistance, ribosomal proteins, the stress response, transcription, translation, and transport and binding proteins at significantly higher levels than cells grown in Luria broth. These results suggest thatE. coliO157:H7 may develop a different phenotype during transport through the environment. Furthermore, this pathogen may become more resistant to antibiotics making subsequent infections more difficult to treat.

scholarly journals Interplay between IncF plasmids and topoisomerase mutations conferring quinolone resistance in the Escherichia coli ST131 clone: stability and resistance evolution

2021 ◽  
Author(s):  
Jose-Manuel Rodríguez-Martínez ◽  
Lorena Lopez-Cerero ◽  
Ana García-Duque ◽  
Jesus Rodriguez-Baño ◽  
Alvaro Pascual
Keyword(s):  
Escherichia Coli ◽  
Plasmid Stability ◽  
Luria Broth ◽  
Quinolone Resistance ◽  
Experimental Conditions ◽  
E Coli ◽  
The Stability ◽  
The Impact ◽  
Mutant Frequency

Abstract The Escherichia coli ST131 H30-Rx subclone vehicles CTX-M-15 plasmids and mutations in gyrA and parC conferring multidrug resistance successfully in the clinical setting. The aim of this study was (1) to investigate the relationship of specific topoisomerase mutations on the stability of IncF (CTX-M producing) plasmids using isogenic E. coli mutants and (2) to investigate the impact of the IncF-type plasmids present in the E. coli clone ST131 on the evolution of quinolone resistance. E. coli ATCC 25922 (background strain) and derived mutants encoding specific QRDR substitutions were used. Also, NGS-characterized IncFIA and IncFIB plasmids (encoding CTX-M genes) were included. Plasmid stability was evaluated by sequential dilutions into Luria broth medium without antibiotics for 7 days. Mutant frequency to ciprofloxacin was also evaluated. Moderate differences in the IncF plasmids stability were observed among E. coli ATCC 25922 and isogenic mutants. Under our experimental conditions, the fluctuation of bacteria harboring plasmids was less than 0.5-log(10) in all cases. In the mutant frequency tests, it was observed that the presence of these IncF plasmids increased this value significantly (10–1000-fold). Quinolone resistance substitutions in gyrA or parC genes, frequently found associated with E. coli clone ST131, do not modify the stability of ST131-associated IncFIA and IncFIB plasmids under in vitro conditions. IncF-type plasmids present in E. coli clone ST131 facilitate the selection of resistance to quinolones. These results are consistent with the clinical scenario in which the combination of resistance to quinolones and beta-lactams is highly frequent in the E. coli clone ST131.

scholarly journals In vitro reconstitution of the GTPase-associated centre of the archaebacterial ribosome: the functional features observed in a hybrid form with Escherichia coli 50S subunits

2006 ◽  
Vol 396 (3) ◽  
pp. 565-571 ◽  
Author(s):  
Takaomi Nomura ◽  
Kohji Nakano ◽  
Yasushi Maki ◽  
Takao Naganuma ◽  
Takashi Nakashima ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Ribosomal Proteins ◽  
Synthetic Activity ◽  
23S Rrna ◽  
Elongation Factors ◽  
Hybrid Form ◽  
Pyrococcus Horikoshii ◽  
E Coli ◽  
Functional Features

We cloned the genes encoding the ribosomal proteins Ph (Pyrococcus horikoshii)-P0, Ph-L12 and Ph-L11, which constitute the GTPase-associated centre of the archaebacterium Pyrococcus horikoshii. These proteins are homologues of the eukaryotic P0, P1/P2 and eL12 proteins, and correspond to Escherichia coli L10, L7/L12 and L11 proteins respectively. The proteins and the truncation mutants of Ph-P0 were overexpressed in E. coli cells and used for in vitro assembly on to the conserved domain around position 1070 of 23S rRNA (E. coli numbering). Ph-L12 tightly associated as a homodimer and bound to the C-terminal half of Ph-P0. The Ph-P0·Ph-L12 complex and Ph-L11 bound to the 1070 rRNA fragments from the three biological kingdoms in the same manner as the equivalent proteins of eukaryotic and eubacterial ribosomes. The Ph-P0·Ph-L12 complex and Ph-L11 could replace L10·L7/L12 and L11 respectively, on the E. coli 50S subunit in vitro. The resultant hybrid ribosome was accessible for eukaryotic, as well as archaebacterial elongation factors, but not for prokaryotic elongation factors. The GTPase and polyphenylalanine-synthetic activity that is dependent on eukaryotic elongation factors was comparable with that of the hybrid ribosomes carrying the eukaryotic ribosomal proteins. The results suggest that the archaebacterial proteins, including the Ph-L12 homodimer, are functionally accessible to eukaryotic translation factors.

scholarly journals PHAGOCYTOSIS OF BACTERIA IN THE ABSENCE OF ANTIBODY AND THE EFFECT OF PHYSICAL SURFACE

1956 ◽  
Vol 104 (2) ◽  
pp. 233-243 ◽  
Author(s):  
Edwin M. Lerner
Keyword(s):  
Filter Paper ◽  
Chemical Effect ◽  
Type I ◽  
Blood Leukocytes ◽  
Experimental Conditions ◽  
Phagocytic Capacity ◽  
E Coli ◽  
Physical Surface ◽  
Type Iv

The present experiments have shown that phagocytosis occurs in the absence of specific antibody and in the absence of a "suitable physical surface", as further that the presence of a rough surface does not increase the in vitro phagocytosis of pneumococci by polymorphonuclear leukocytes. This held true during repetition of Wood's experiments, as well as when more controlled quantitative techniques were employed, when conditions were made optimal for phagocytosis by increasing bacterial concentrations, and when blood leukocytes were substituted for exudate leukocytes. Evidence has been presented previously that the stimulation of phagocytosis of E. coli, B. abortus, and Type IV Pneumococcus, after contact with filter paper or an active compound present in filter paper, is a chemical effect rather than a physical effect. This type of stimulation did not occur with the Type I A5 Pneumococcus. The leukocyte of the circulating blood was found to be definitely superior to the exudate leukocyte in phagocytic capacity, under all the experimental conditions tested.

scholarly journals Transcription of bacteriophage T4 deoxyribonucleic acid in vitro

1969 ◽  
Vol 115 (3) ◽  
pp. 353-361 ◽  
Author(s):  
John O. Bishop ◽  
Forbes W. Robertson
Keyword(s):  
Rna Polymerase ◽  
Messenger Rna ◽  
Rna Synthesis ◽  
Deoxyribonucleic Acid ◽  
Bacteriophage T4 ◽  
Rna Sequences ◽  
Experimental Conditions ◽  
E Coli ◽  
New Methods

1. RNA was synthesized in vitro from a template of bacteriophage T4 DNA, in the presence of Mn2+. A comparison was made of the RNA synthesized by purified RNA polymerase from two sources, Micrococcus lysodeikticus and Escherichia coli; these are referred to as Micrococcus cRNA and E. coli cRNA respectively (where cRNA indicates RNA synthesized in vitro by using purified RNA polymerase and a DNA primer). 2. Both types of RNA were self-complementary as judged by resistance to digestion with ribonuclease after self-annealing, Micrococcus cRNA being more self-complementary (40%) than was E. coli cRNA (30%). The cRNA was found to be much less self-complementary if Mg2+ was present during RNA synthesis instead of Mn2+. 3. Micrococcus cRNA hybridized with a larger part of bacteriophage T4 DNA than did E. coli cRNA. The E. coli cRNA competed with only part (70%) of the Micrococcus cRNA in hybridization-competition experiments. It is concluded that more sequences of bacteriophage T4 DNA are transcribed by Micrococcus polymerase than by E. coli polymerase. 4. The RNA sequences synthesized by Micrococcus RNA polymerase but not by E. coli RNA polymerase are shown by hybridization competition to compete with specifically late bacteriophage T4 messenger RNA sequences. The relevance of this finding to the control of transcription is discussed. 5. In an Appendix, new methods are described for the analysis of hybridization-saturation and -competition experiments. Particular attention is paid to the effects produced if different RNA sequences are present at different relative concentrations. 6. By using cRNA isolated from an enzymically synthesized DNA–RNA hybrid, it is estimated that, of the DNA that is complementary to cRNA, only about half can become hybridized with cRNA under the experimental conditions used.

scholarly journals Antibiotic Resistance Patterns in a University Hospital in Al-Kharj City

2019 ◽  
pp. 1-5
Author(s):  
Nehad J. Ahmed ◽  
Mohd F. Khan
Keyword(s):  
Antibiotic Resistance ◽  
Bacterial Resistance ◽  
Treatment Guidelines ◽  
Resistance Rate ◽  
University Hospital ◽  
Antimicrobial Drugs ◽  
E Coli ◽  
Resistance Patterns ◽  
Antibiotic Resistance Patterns

Introduction: Antibiotics are medications that are used to kill a bacterium which causes different infections. The misuse of these medications has contributed to the development of bacterial resistance. In order to predict the efficacy of the antimicrobial drugs and to guide antimicrobial therapy, antibiogram should be used. Objective: This study aims to explore the Antibiotic resistance patterns in a university hospital in AL-kharj city. Methods: Data from a university hospital in Al-Kharj city were used to assess the in vitro antimicrobial susceptibility rates for different types of bacteria. We included all bacterial and fungal cultures in the last 2 years. Results: The most common bacterium was E. coli and the most common fungus pathogen was Candida albicans. There was a low resistance rate to gentamicin, imipenem, meropenem and amikacin for the studied bacteria pathogens and high resistance rate for some antibiotics such as erythromycin, tetracycline and ampicillin. Conclusion: The physicians should follow the treatment guidelines and they should know the susceptibility rate of different bacteria to prescribe antibiotics appropriately.

scholarly journals Development of evolution drugs - antibacterial compounds that block pathways to resistance

2020 ◽  
Author(s):  
Yanmin Zhang ◽  
Sourav Chowdhury ◽  
João V. Rodrigues ◽  
Eugene Shakhnovich
Keyword(s):  
Antibiotic Resistance ◽  
Dihydrofolate Reductase ◽  
Experimental Approach ◽  
Whole Genome ◽  
Bacterial Protein ◽  
Antibacterial Compounds ◽  
E Coli ◽  
Resistant Strains ◽  
Resistant Mutants

AbstractAntibiotic resistance is a worldwide challenge. A potential approach to block resistance is to simultaneously inhibit WT and known escape variants of the target bacterial protein. Here we applied an integrated computational and experimental approach to discover compounds that inhibit both WT and trimethoprim (TMP) resistant mutants of E. coli dihydrofolate reductase (DHFR). We identified a novel compound (CD15-3) that inhibits WT DHFR and its TMP resistant variants L28R, P21L and A26T with IC50 50-75 μM against WT and TMP-resistant strains. Resistance to CD15-3 was dramatically delayed compared to TMP in in vitro evolution. Whole genome sequencing of CD15-3 resistant strains showed no mutations in the target folA locus. Rather, gene duplication of several efflux pumps gave rise to weak (about twofold increase in IC50) resistance against CD15-3. Altogether, our results demonstrate the promise of strategy to develop evolution drugs - compounds which block evolutionary escape routes in pathogens.

Increasing Antibiotic Resistance Among Isolates ofEscherichia coliRecovered From Inpatients and Outpatients in a Saudi Arabian Hospital

2006 ◽  
Vol 27 (7) ◽  
pp. 748-753 ◽  
Author(s):  
Jaffar A. Al-Tawfiq
Keyword(s):  
Antibiotic Resistance ◽  
Multidrug Resistance ◽  
Antimicrobial Agents ◽  
Saudi Arabian ◽  
Susceptibility Pattern ◽  
Antibiotic Susceptibility Pattern ◽  
E Coli ◽  
Culture Positive ◽  
Low Rate

Objective.To study the pattern of antibiotic resistance amongEscherichia coliand the trend in resistance during a 6-year period in a Saudi Arabian hospital.Design.Retrospective in vitro surveillance study of the antibiotic susceptibility pattern amongE. coliisolates recovered from outpatients and from inpatients.Setting.A general hospital in Saudi Arabia.Patients.All patients with a culture positive forE. coliduring a 6-year study period.Results.A statistically significant increase in antibiotic resistance was observed among outpatient and inpatient isolates ofE, coli.Inpatient isolates were more likely to be resistant to antimicrobial agents. Among isolates from outpatients, 50% were resistant to ampicillin, 33% were resistant to trimethoprim-sulfamethoxazole (TMP-SMZ), and 14% were resistant to ciprofloxacin. Among isolates from inpatients, 63% were resistant to ampicillin, 44% were resistant to TMP-SMZ, and 33% were resistant to ciprofloxacin. There was a low rate of resistance to imipenem (0.3% of isolates), amikacin (2%), and nitrofurantoin (2.4%-6.5%). Resistance to ceftazidime was detected in 9% of outpatient isolates and 17% of inpatient isolates. Multidrug resistance was defined as resistance to 2 or more classes of antibiotics. Multidrug resistance was detected in 2.0%-28.1% of outpatient isolates and 7.4%-39.6% of inpatient isolates, depending on the combination of antimicrobials tested. More isolates were resistant to ampicillin plus TMP-SMZ than to any other combination of antimicrobials.Conclusion.The prevalence of antibiotic resistance among outpatient and inpatientE. coliisolates increased during the study period. The rates of antibiotic resistance were statistically significantly higher among inpatient isolates, compared with outpatient isolates. These findings call for wiser use of antibiotics and continued surveillance of antibiotic resistance.

scholarly journals Gene Expression Analysis of the Streptococcus pneumoniae Competence Regulons by Use of DNA Microarrays

2000 ◽  
Vol 182 (21) ◽  
pp. 6192-6202 ◽  
Author(s):  
Scott Peterson ◽  
Robin T. Cline ◽  
Hervé Tettelin ◽  
Vasily Sharov ◽  
Donald A. Morrison
Keyword(s):  
Streptococcus Pneumoniae ◽  
Dna Microarrays ◽  
Target Genes ◽  
Expression Patterns ◽  
In Vitro Models ◽  
Regulatory Genes ◽  
Mrna Levels ◽  
Similar Expression Pattern ◽  
Genes Encoding

ABSTRACT Competence for genetic transformation in Streptococcus pneumoniae is coordinated by the competence-stimulating peptide (CSP), which induces a sudden and transient appearance of competence during exponential growth in vitro. Models of this quorum-sensing mechanism have proposed sequential expression of several regulatory genes followed by induction of target genes encoding DNA-processing-pathway proteins. Although many genes required for transformation are known to be expressed only in response to CSP, the relative timing of their expression has not been established. Overlapping expression patterns for the genes cinA andcomD (G. Alloing, B. Martin, C. Granadel, and J. P. Claverys, Mol. Microbiol. 29:75–83, 1998) suggest that at least two distinct regulatory mechanisms may underlie the competence cycle. DNA microarrays were used to estimate mRNA levels for all known competence operons during induction of competence by CSP. The known competence regulatory operons, comAB, comCDE, andcomX, exhibited a low or zero initial (uninduced) signal, strongly increased expression during the period between 5 and 12 min after CSP addition, and a decrease nearly to original values by 15 min after initiation of exposure to CSP. The remaining competence genes displayed a similar expression pattern, but with an additional delay of approximately 5 min. In a mutant defective in ComX, which may act as an alternate sigma factor to allow expression of the target competence genes, the same regulatory genes were induced, but the other competence genes were not. Finally, examination of the expression of 60 candidate sites not previously associated with competence identified eight additional loci that could be induced by CSP.

scholarly journals Single Ribosomal Protein Mutations in Antibiotic-Resistant Bacteria Analyzed by Mass Spectrometry

2001 ◽  
Vol 45 (11) ◽  
pp. 3046-3055 ◽  
Author(s):  
Sheri K. Wilcox ◽  
Gregory S. Cavey ◽  
James D. Pearson
Keyword(s):  
Mass Spectrometry ◽  
Antibiotic Resistance ◽  
Ribosomal Proteins ◽  
Resistant Bacteria ◽  
Antibiotic Resistant ◽  
Mutant Proteins ◽  
E Coli ◽  
Maldi Tof ◽  
Molecular Masses

ABSTRACT Mutations in several ribosomal proteins are known to be related to antibiotic resistance. For several strains of Escherichia coli, the mutated protein is known but the amino acid actually altered has not been documented. Characterization of these determinants for antibiotic resistance in proteins will further the understanding of the precise mechanism of the antibiotic action as well as provide markers for resistance. Mass spectrometry can be used as a valuable tool to rapidly locate and characterize mutant proteins by using a small amount of material. We have used electrospray and matrix-assisted laser desorption ionization–time of flight (MALDI–TOF) mass spectrometry to map out all 56 ribosomal proteins in E. coli based on intact molecular masses. We used this fingerprinting approach to locate variants of ribosomal proteins displaying a change in mass. In particular we have studied proteins responsible for streptomycin, erythromycin, and spectinomycin resistance in three strains of E. coli, and then we characterized each mutation responsible for resistance by analyzing tryptic peptides of these proteins by using MALDI-TOF and nanoelectrospray tandem mass spectrometry. The results provided markers for antibiotic resistance and demonstrated that mass spectrometry can be used to rapidly investigate changes in individual proteins from a complex with picomole amounts of protein.

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