scholarly journals A qnr-plasmid allows aminoglycosides to induce SOS in Escherichia coli

2021 ◽  
Author(s):  
Anamaria Babosan ◽  
David Skurnik ◽  
Anaëlle Muggeo ◽  
Gerald Pier ◽  
Thomas Jové ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Bacterial Resistance ◽  
Sos Response ◽  
E Coli ◽  
Fluoroquinolone Antibiotics ◽  
Plasmid Genes ◽  
High Level ◽  
Emergence Of Resistance ◽  
Fad Binding

The plasmid-mediated quinolone resistance (PMQR) genes have been shown to promote high level bacterial resistance to fluoroquinolone antibiotics, potentially leading to clinical treatment failures. In Escherichia coli, sub-inhibitory concentrations (sub-MIC) of the widely used fluoroquinolones are known to induce the SOS response. Interestingly, the expression of several PMQR qnr genes is controlled by the SOS master regulator. During the characterization of a small qnrD-plasmid carried in E. coli, we observed that the aminoglycosides become able to induce the SOS response in this species, thus leading to the transcription of qnrD. We found that induction of the SOS response is due to nitric oxide (NO) accumulation in presence of sub-MIC of aminoglycosides. We demonstrated that the NO accumulation is driven by two plasmid genes, ORF3 and ORF4, whose products act at two levels. ORF3 encode a FAD-binding oxidoreductase which helps NO synthesis, while ORF4 code for an FNR-type transcription factor, related to an O2-responsive regulator of hmp expression, able to repress the Hmp-mediated NO detoxification pathway of E. coli. Thus, this discovery, that other major classes of antibiotics may induce the SOS response could have worthwhile implications for antibiotic stewardship efforts in preventing the emergence of resistance.

scholarly journals A newly identified prophage-encoded gene, ymfM, causes SOS-inducible filamentation in Escherichia coli

2021 ◽  
Author(s):  
Shirin Ansari ◽  
James C. Walsh ◽  
Amy L. Bottomley ◽  
Iain G. Duggin ◽  
Catherine Burke ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Cell Division ◽  
Pathogenic Bacteria ◽  
Bacterial Resistance ◽  
Sos Response ◽  
E Coli ◽  
Ring Assembly ◽  
Multiple Alternative ◽  
Z Ring ◽  
Cell Division Inhibitor

Rod-shaped bacteria such as Escherichia coli can regulate cell division in response to stress, leading to filamentation, a process where cell growth and DNA replication continues in the absence of division, resulting in elongated cells. The classic example of stress is DNA damage which results in the activation of the SOS response. While the inhibition of cell division during SOS has traditionally been attributed to SulA in E. coli, a previous report suggests that the e14 prophage may also encode an SOS-inducible cell division inhibitor, previously named SfiC. However, the exact gene responsible for this division inhibition has remained unknown for over 35 years. A recent high-throughput over-expression screen in E. coli identified the e14 prophage gene, ymfM, as a potential cell division inhibitor. In this study, we show that the inducible expression of ymfM from a plasmid causes filamentation. We show that this expression of ymfM results in the inhibition of Z ring formation and is independent of the well characterised inhibitors of FtsZ ring assembly in E. coli, SulA, SlmA and MinC. We confirm that ymfM is the gene responsible for the SfiC phenotype as it contributes to the filamentation observed during the SOS response. This function is independent of SulA, highlighting that multiple alternative division inhibition pathways exist during the SOS response. Our data also highlight that our current understanding of cell division regulation during the SOS response is incomplete and raises many questions regarding how many inhibitors there actually are and their purpose for the survival of the organism. Importance: Filamentation is an important biological mechanism which aids in the survival, pathogenesis and antibiotic resistance of bacteria within different environments, including pathogenic bacteria such as uropathogenic Escherichia coli. Here we have identified a bacteriophage-encoded cell division inhibitor which contributes to the filamentation that occurs during the SOS response. Our work highlights that there are multiple pathways that inhibit cell division during stress. Identifying and characterising these pathways is a critical step in understanding survival tactics of bacteria which become important when combating the development of bacterial resistance to antibiotics and their pathogenicity.

scholarly journals A newly identified prophage-encoded gene, ymfM, causes SOS-inducible filamentation in Escherichia coli

2020 ◽  
Author(s):  
Shirin Ansari ◽  
James C. Walsh ◽  
Amy L. Bottomley ◽  
Iain G. Duggin ◽  
Catherine Burke ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Cell Division ◽  
Pathogenic Bacteria ◽  
Bacterial Resistance ◽  
Sos Response ◽  
E Coli ◽  
Ring Assembly ◽  
Z Ring ◽  
Response To Stress ◽  
Cell Division Inhibitor

AbstractRod-shaped bacteria such as Escherichia coli can regulate cell division in response to stress, leading to filamentation, a process where cell growth and DNA replication continues in the absence of division, resulting in elongated cells. The classic example of stress is DNA damage which results in the activation of the SOS response. While the inhibition of cell division during SOS has traditionally been attributed to SulA in E. coli, a previous report suggests that the e14 prophage may also encode an SOS-inducible cell division inhibitor, previously named SfiC. However, the exact gene responsible for this division inhibition has remained unknown for over 35 years. A recent high-throughput over-expression screen in E. coli identified the e14 prophage gene, ymfM, as a potential cell division inhibitor. In this study, we show that the inducible expression of ymfM from a plasmid causes filamentation. We show that this expression of ymfM results in the inhibition of Z ring formation and is independent of the well characterised inhibitors of FtsZ ring assembly in E. coli, SulA, SlmA and MinC. We confirm that ymfM is the gene responsible for the SfiC+ phenotype as it contributes to the filamentation observed during the SOS response. This function is independent of SulA, highlighting that multiple division inhibition pathways exist during the stress-induced SOS response. Our data also highlight that our current understanding of cell division regulation during the SOS response is incomplete and raises many questions regarding how many inhibitors there actually are and their purpose for the survival of the organism.ImportanceFilamentation is an important biological mechanism which aids in the survival, pathogenesis and antibiotic resistance of bacteria within different environments, including pathogenic bacteria such as uropathogenic Escherichia coli. Here we have identified a bacteriophage-encoded cell division inhibitor which contributes to the filamentation that occurs during the SOS response. Our work highlights that there are multiple pathways that inhibit cell division during stress. Identifying and characterising these pathways is a critical step in understanding survival tactics of bacteria which become important when combating the development of bacterial resistance to antibiotics and their pathogenicity.

Genomic characterization of 16S rRNA methyltransferase-producing Escherichia coli isolates from the Parisian area, France

2020 ◽  
Vol 75 (7) ◽  
pp. 1726-1735 ◽  
Author(s):  
François Caméléna ◽  
Florence Morel ◽  
Manel Merimèche ◽  
Jean-Winoc Decousser ◽  
Hervé Jacquier ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
16S Rrna ◽  
Genomic Diversity ◽  
Health Concern ◽  
M Gene ◽  
Genetic Environment ◽  
E Coli ◽  
Genomic Characterization ◽  
High Level

Abstract Background The resistance to all aminoglycosides (AGs) conferred by 16S rRNA methyltransferase enzymes (16S-RMTases) is a major public health concern. Objectives To characterize the resistance genotype, its genetic environment and plasmid support, and the phylogenetic relatedness of 16S-RMTase-producing Escherichia coli from France. Methods We screened 137 E. coli isolates resistant to all clinically relevant AGs from nine Parisian hospitals for 16S-RMTases. WGS was performed on clinical isolates with high-level AG resistance (MIC ≥256 mg/L) and their transformants. Results Thirty of the 137 AG-resistant E. coli produced 16S-RMTases: 11 ArmA, 18 RmtB and 1 RmtC. The 16S-RMTase producers were also resistant to third-generation cephalosporins (90% due to a blaCTX-M gene), co-trimoxazole, fluoroquinolones and carbapenems (blaNDM and blaVIM genes) in 97%, 83%, 70% and 10% of cases, respectively. Phylogenomic diversity was high in ArmA producers, with 10 different STs, but a similar genetic environment, with the Tn1548 transposon carried by a plasmid closely related to pCTX-M-3 in 6/11 isolates. Conversely, RmtB producers belonged to 12 STs, the most frequent being ST405 and ST complex (STc) 10 (four and four isolates, respectively). The rmtB gene was carried by IncF plasmids in 10 isolates and was found in different genetic environments. The rmtC gene was carried by the pNDM-US plasmid. Conclusions ArmA and RmtB are the predominant 16S-RMTases in France, but their spread follows two different patterns: (i) dissemination of a conserved genetic support carrying armA in E. coli with high levels of genomic diversity; and (ii) various genetic environments surrounding rmtB in clonally related E. coli.

scholarly journals Characterization of the fomA andfomB Gene Products from Streptomyces wedmorensis, Which Confer Fosfomycin Resistance on Escherichia coli

2000 ◽  
Vol 44 (3) ◽  
pp. 647-650 ◽  
Author(s):  
Seiji Kobayashi ◽  
Tomohisa Kuzuyama ◽  
Haruo Seto
Keyword(s):  
Escherichia Coli ◽  
Resistance Mechanism ◽  
Biosynthetic Gene Cluster ◽  
Magnesium Ion ◽  
Gene Products ◽  
Biosynthetic Gene ◽  
E Coli ◽  
Fosfomycin Resistance ◽  
High Level

ABSTRACT Together, the fomA and fomB genes in the fosfomycin biosynthetic gene cluster of Streptomyces wedmorensis confer high-level fosfomycin resistance onEscherichia coli. To elucidate their functions, thefomA and fomB genes were overexpressed inE. coli and the gene products were characterized. The recombinant FomA protein converted fosfomycin to fosfomycin monophosphate, which was inactive on E. coli, in the presence of a magnesium ion and ATP. On the other hand, the recombinant FomB protein did not inactivate fosfomycin. However, a reaction mixture containing FomA and FomB proteins converted fosfomycin to fosfomycin monophosphate and fosfomycin diphosphate in the presence of ATP and a magnesium ion, indicating that FomA and FomB catalyzed phosphorylations of fosfomycin and fosfomycin monophosphate, respectively. These results suggest that the self-resistance mechanism of the fosfomycin-producing organism S. wedmorensis is mono- and diphosphorylation of the phosphonate function of fosfomycin catalyzed by FomA and FomB.

scholarly journals Phenotypic and genotypic characterization of mcr-1-positive multidrug-resistant Escherichia coli ST93, ST117, ST156, ST10, and ST744 isolated from poultry in Poland

2021 ◽  
Author(s):  
Katarzyna Ćwiek ◽  
Anna Woźniak-Biel ◽  
Magdalena Karwańska ◽  
Magdalena Siedlecka ◽  
Christine Lammens ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Resistance ◽  
Resistance Genes ◽  
Bacterial Resistance ◽  
Antimicrobial Agents ◽  
Genetic Relatedness ◽  
Multidrug Resistant ◽  
E Coli ◽  
Antimicrobial Resistance Genes

Abstract Background A plasmid-mediated mechanism of bacterial resistance to polymyxin is a serious threat to public health worldwide. The present study aimed to determine the occurrence of plasmid-mediated colistin resistance genes and to conduct the molecular characterization of mcr-positive Escherichia coli strains isolated from Polish poultry. Methods In this study, 318 E. coli strains were characterized by the prevalence of mcr1–mcr5 genes, antimicrobial susceptibility testing by minimal inhibitory concentration method, the presence of antimicrobial resistance genes was screened by PCR, and the biofilm formation ability was tested using the crystal violet staining method. Genetic relatedness of mcr-1-positive E. coli strains was evaluated by multilocus sequence typing method. Results Among the 318 E. coli isolates, 17 (5.35%) harbored the mcr-1 gene. High antimicrobial resistance rates were observed for ampicillin (100%), tetracycline (88.24%), and chloramphenicol (82.35%). All mcr-1-positive E. coli strains were multidrug-resistant, and as many as 88.24% of the isolates contained the blaTEM gene, tetracycline (tetA and tetB), and sulfonamide (sul1, sul2, and sul3) resistance genes. Additionally, 41.18% of multidrug-resistant, mcr-1-positive E. coli isolates were moderate biofilm producers, while the rest of the strains showed weak biofilm production. Nine different sequence types were identified, and the dominant ST was ST93 (29.41%), followed by ST117 (17.65%), ST156 (11.76%), ST 8979 (11.76%), ST744 (5.88%), and ST10 (5.88%). Moreover, the new ST was identified in this study. Conclusions Our results showed a low occurrence of mcr-1-positive E. coli strains isolated from Polish poultry; however, all the isolated strains were resistant to multiple antimicrobial agents and were able to form biofilms at low or medium level.

scholarly journals Preparation and characterization of human interleukin-5 expressed in recombinant Escherichia coli

1990 ◽  
Vol 270 (2) ◽  
pp. 357-361 ◽  
Author(s):  
A E I Proudfoot ◽  
D Fattah ◽  
E H Kawashima ◽  
A Bernard ◽  
P T Wingfield
Keyword(s):  
Escherichia Coli ◽  
Inducible Promoter ◽  
Cellular Protein ◽  
Biological Assays ◽  
Interleukin 5 ◽  
E Coli ◽  
Gene Coding ◽  
High Level

The gene coding for human interleukin-5 was synthesized and expressed in Escherichia coli under control of a heat-inducible promoter. High-level expression, 10-15% of total cellular protein, was achieved in E. coli. The protein was produced in an insoluble state. A simple extraction, renaturation and purification scheme is described. The recombinant protein was found to be a homodimer, similar to the natural murine-derived protein. Despite the lack of glycosylation, high specific activities were obtained in three ‘in vitro’ biological assays. Physical characterization of the protein showed it to be mostly alpha-helical, supporting the hypothesis that a conformational similarity exists among certain cytokines.

scholarly journals Distribution of espM and espT among enteropathogenic and enterohaemorrhagic Escherichia coli

2009 ◽  
Vol 58 (8) ◽  
pp. 988-995 ◽  
Author(s):  
Ana Arbeloa ◽  
Miguel Blanco ◽  
Fabiana C. Moreira ◽  
Richard Bulgin ◽  
Cecilia López ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Rho Gtpases ◽  
Virulence Gene ◽  
Gene Repertoire ◽  
E Coli ◽  
Enterohaemorrhagic Escherichia Coli ◽  
Household Members ◽  
High Level ◽  
Human Infections

Enterohaemorrhagic Escherichia coli (EHEC) and enteropathogenic E. coli (EPEC) translocate dozens of type III secretion system effectors, including the WxxxE effectors Map, EspM and EspT that activate Rho GTPases. While map, which is carried on the LEE pathogenicity island, is absolutely conserved among EPEC and EHEC strains, the prevalence of espM and espT is not known. Here we report the results of a large screen aimed at determining the prevalence of espM and espT among clinical EPEC and EHEC isolates. The results suggest that espM, detected in 51 % of the tested strains, is more commonly found in EPEC and EHEC serogroups that are linked to severe human infections. In contrast, espT was absent from all the EHEC isolates and was found in only 1.8 % of the tested EPEC strains. Further characterization of the virulence gene repertoire of the espT-positive strains led to the identification of a new ζ2 intimin variant. All the espT-positive strains but two contained the tccP gene. espT was first found in Citrobacter rodentium and later in silico in EPEC E110019, which is of particular interest as this strain was responsible for a particularly severe diarrhoeal outbreak in Finland in 1987 that affected 650 individuals in a school complex and an additional 137 associated household members. Comparing the protein sequences of EspT to that of E110019 showed a high level of conservation, with only three strains encoding EspT that differed in 6 amino acids. At present, it is not clear why espT is so rare, and what impact EspM and EspT have on EPEC and EHEC infection.

scholarly journals Curli Fibers Are Highly Conserved between Salmonella typhimurium and Escherichia coli with Respect to Operon Structure and Regulation

1998 ◽  
Vol 180 (3) ◽  
pp. 722-731 ◽  
Author(s):  
Ute Römling ◽  
Zhao Bian ◽  
Mårten Hammar ◽  
Walter D. Sierralta ◽  
Staffan Normark
Keyword(s):  
Escherichia Coli ◽  
Salmonella Typhimurium ◽  
Transcriptional Activation ◽  
Protein Level ◽  
Amino Acid Homology ◽  
E Coli ◽  
Low Copy Number ◽  
High Level ◽  
High Degree

ABSTRACT Mouse-virulent Salmonella typhimurium strains SR-11 and ATCC 14028-1s express curli fibers, thin aggregative fibers, at ambient temperature on plates as judged by Western blot analysis and electron microscopy. Concomitantly with curli expression, cells develop a rough and dry colony morphology and bind the dye Congo red (called the rdar morphotype). Cloning and characterization of the two divergently transcribed operons required for curli biogenesis, csgBA(C)and csgDEFG, from S. typhimurium SR-11 revealed the same gene order and flanking genes as in Escherichia coli. The divergence of the curli region between S. typhimurium and E. coli at the nucleotide level is above average (22.4%). However, a high level of conservation at the protein level, which ranged from 86% amino acid homology for the fiber subunit CsgA to 99% homology for the lipoprotein CsgG, implies functional constraints on the gene products. Consequently, S. typhimurium genes on low-copy-number plasmids were able to complement respective E. coli mutants, although not always to wild-type levels. rpoS and ompR are required for transcriptional activation of (at least) the csgDpromoter. The high degree of conservation at the protein level and the identical regulation patterns in E. coli and S. typhimurium suggest similar roles of curli fibers in the same ecological niche in the two species.

scholarly journals Molecular characterization of beta-lactamase genes produced by community-acquired uropathogenic Escherichia coli in Nouna

2020 ◽  
Vol 14 (11) ◽  
pp. 1274-1280
Author(s):  
Dramane Kiemde ◽  
Inês Ribeiro ◽  
Soufiane Sanou ◽  
Boubacar Coulibaly ◽  
Ali Sie ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Molecular Characterization ◽  
Bacterial Resistance ◽  
Uropathogenic Escherichia Coli ◽  
Common Mechanism ◽  
Beta Lactamase ◽  
E Coli ◽  
Extended Spectrum Beta Lactamases ◽  
Synergy Test

Introduction: Extended-Spectrum Beta-Lactamases (ESBL) are a common mechanism of bacterial resistance in Enterobacteriaceae. The purpose of this study is to characterize the ESBL genes produced by community-acquired uropathogenic Escherichia coli strains in the Nouna District, in the West-African country, Burkina Faso. Methodology: Samples were collected from non-hospitalized patients who came for consultation at the CMA (Centre Médical avec Antenne chirurgicale) in Nouna and were sent to the laboratory for a urine culture test. The detection of ESBL production by the bacteria was carried out with the double-disc synergy test and the extraction of the ESBL genes with the heat shock method. Molecular characterization of ESBL genes was performed with three sequential multiplex polymerase chain reaction (PCR) assays. Results: One hundred and eighty-two (182) bacteriological cultures were analyzed and 29 E. coli isolated, between 01/07/2017 and 01/07/2018. The ESBL phenotype was found in 13/29 (44.8%). Multiplex PCR yielded many beta-lactamase genes, predominantly blaCTX-M-1,3,15 (12/13; 92.3%) followed by beta-lactamase genes blaOXA-1,4,30 (8/13; 61.5%) and beta-lactamase genes blaTEM-1,2 (7/13; 53.8%). Conclusion: This study showed that the blaCTX-M-1,3,15 genes produced by uropathogenic E. coli were predominant. Sequencing of these genes would be needed to better characterize the different types of ESBL circulating in Nouna.

scholarly journals Sequence Analysis and Characterization of a Transferable Hybrid Plasmid Encoding Multidrug Resistance and Enabling Zoonotic Potential for Extraintestinal Escherichia coli

2010 ◽  
Vol 78 (5) ◽  
pp. 1931-1942 ◽  
Author(s):  
Timothy J. Johnson ◽  
Dianna Jordan ◽  
Subhashinie Kariyawasam ◽  
Adam L. Stell ◽  
Nathan P. Bell ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Multidrug Resistance ◽  
Sequence Analysis ◽  
Rat Model ◽  
Antimicrobial Agents ◽  
Neonatal Meningitis ◽  
E Coli ◽  
High Level ◽  
Plasmid Backbone

ABSTRACT ColV plasmids of extraintestinal pathogenic Escherichia coli (ExPEC) encode a variety of fitness and virulence factors and have long been associated with septicemia and avian colibacillosis. These plasmids are found significantly more often in ExPEC, including ExPEC associated with human neonatal meningitis and avian colibacillosis, than in commensal E. coli. Here we describe pAPEC-O103-ColBM, a hybrid RepFIIA/FIB plasmid harboring components of the ColV pathogenicity island and a multidrug resistance (MDR)-encoding island. This plasmid is mobilizable and confers the ability to cause septicemia in chickens, the ability to cause bacteremia resulting in meningitis in the rat model of human disease, and the ability to resist the killing effects of multiple antimicrobial agents and human serum. The results of a sequence analysis of this and other ColV plasmids supported previous findings which indicated that these plasmid types arose from a RepFIIA/FIB plasmid backbone on multiple occasions. Comparisons of pAPEC-O103-ColBM with other sequenced ColV and ColBM plasmids indicated that there is a core repertoire of virulence genes that might contribute to the ability of some ExPEC strains to cause high-level bacteremia and meningitis in a rat model. Examination of a neonatal meningitis E. coli (NMEC) population revealed that approximately 58% of the isolates examined harbored ColV-type plasmids and that 26% of these plasmids had genetic contents similar to that of pAPEC-O103-ColBM. The linkage of the ability to confer MDR and the ability contribute to multiple forms of human and animal disease on a single plasmid presents further challenges for preventing and treating ExPEC infections.

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