scholarly journals Growth of Escherichia coli in Model Distribution System Biofilms Exposed to Hypochlorous Acid or Monochloramine

2003 ◽  
Vol 69 (9) ◽  
pp. 5463-5471 ◽  
Author(s):  
Margaret M. Williams ◽  
Ellen B. Braun-Howland
Keyword(s):  
Escherichia Coli ◽  
Legionella Pneumophila ◽  
Distribution System ◽  
Distribution Systems ◽  
Hypochlorous Acid ◽  
Bacterial Species ◽  
Phylogenetic Groups ◽  
Bacterial Populations ◽  
E Coli ◽  
Model Distribution

ABSTRACT Bacteria indigenous to water distribution systems were used to grow multispecies biofilms within continuous-flow slide chambers. Six flow chambers were also inoculated with an Escherichia coli isolate obtained from potable water. The effect of disinfectants on bacterial populations was determined after exposure of established biofilms to 1 ppm of hypochlorous acid (ClOH) for 67 min or 4 ppm of monochloramine (NH2Cl) for 155 min. To test the ability of bacterial populations to initiate biofilm formation in the presence of disinfectants, we assessed the biofilms after 2 weeks of exposure to residual concentrations of 0.2 ppm of ClOH or 4 ppm of NH2Cl. Lastly, to determine the effect of recommended residual concentrations on newly established biofilms, we treated systems with 0.2 ppm of ClOH after 5 days of growth in the absence of disinfectant. Whole-cell in situ hybridizations using fluorescently tagged, 16S rRNA-targeted oligonucleotide probes performed on cryosectioned biofilms permitted the direct observation of metabolically active bacterial populations, including certain phylogenetic groups and species. The results of these studies confirmed the resistance of established bacterial biofilms to treatment with recommended levels of disinfectants. Specifically, Legionella pneumophila, E. coli, and β and δ proteobacteria were identified within biofilms both before and after treatment. Furthermore, although it was undetected using routine monitoring techniques, the observation of rRNA-containing E. coli within biofilms demonstrated not only survival but also metabolic activity of this organism within the model distribution systems. The persistence of diverse bacterial species within disinfectant-treated biofilms suggests that current testing practices underestimate the risk to immunocompromised individuals of contracting waterborne disease.

scholarly journals Effect of Phosphorus on Survival of Escherichia coli in Drinking Water Biofilms

2007 ◽  
Vol 73 (11) ◽  
pp. 3755-3758 ◽  
Author(s):  
Talis Juhna ◽  
Dagne Birzniece ◽  
Janis Rubulis
Keyword(s):  
Escherichia Coli ◽  
Drinking Water ◽  
Distribution System ◽  
Distribution Systems ◽  
Water Distribution ◽  
Water Distribution System ◽  
Phosphorus Addition ◽  
Drinking Water Distribution Systems ◽  
E Coli ◽  
Drinking Water Distribution

ABSTRACT The effect of phosphorus addition on survival of Escherichia coli in an experimental drinking water distribution system was investigated. Higher phosphorus concentrations prolonged the survival of culturable E. coli in water and biofilms. Although phosphorus addition did not affect viable but not culturable (VBNC) E. coli in biofilms, these structures could act as a reservoir of VBNC forms of E. coli in drinking water distribution systems.

scholarly journals The Chaperone and Redox Properties of CnoX Chaperedoxins Are Tailored to the Proteostatic Needs of Bacterial Species

mBio ◽  
2018 ◽  
Vol 9 (6) ◽  
Author(s):  
Camille V. Goemans ◽  
François Beaufay ◽  
Isabelle S. Arts ◽  
Rym Agrebi ◽  
Didier Vertommen ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Hypochlorous Acid ◽  
Caulobacter Crescentus ◽  
Bacterial Species ◽  
Redox Properties ◽  
Antioxidant Defenses ◽  
Protective Function ◽  
Content Type ◽  
E Coli ◽  
Induced Aggregation

ABSTRACT Hypochlorous acid (bleach), an oxidizing compound produced by neutrophils, turns the Escherichia coli chaperedoxin CnoX into a powerful holdase protecting its substrates from bleach-induced aggregation. CnoX is well conserved in bacteria, even in non-infectious species unlikely to encounter this oxidant, muddying the role of CnoX in these organisms. Here, we found that CnoX in the non-pathogenic aquatic bacterium Caulobacter crescentus functions as a holdase that efficiently protects 50 proteins from heat-induced aggregation. Remarkably, the chaperone activity of Caulobacter CnoX is constitutive. Like E. coli CnoX, Caulobacter CnoX transfers its substrates to DnaK/J/GrpE and GroEL/ES for refolding, indicating conservation of cooperation with GroEL/ES. Interestingly, Caulobacter CnoX exhibits thioredoxin oxidoreductase activity, by which it controls the redox state of 90 proteins. This function, which E. coli CnoX lacks, is likely welcome in a bacterium poorly equipped with antioxidant defenses. Thus, the redox and chaperone properties of CnoX chaperedoxins were fine-tuned during evolution to adapt these proteins to the specific needs of each species. IMPORTANCE How proteins are protected from stress-induced aggregation is a crucial question in biology and a long-standing mystery. While a long series of landmark studies have provided important contributions to our current understanding of the proteostasis network, key fundamental questions remain unsolved. In this study, we show that the intrinsic features of the chaperedoxin CnoX, a folding factor that combines chaperone and redox protective function, have been tailored during evolution to fit to the specific needs of their host. Whereas Escherichia coli CnoX needs to be activated by bleach, a powerful oxidant produced by our immune system, its counterpart in Caulobacter crescentus, a bacterium living in bleach-free environments, is a constitutive chaperone. In addition, the redox properties of E. coli and C. crescentus CnoX also differ to best contribute to their respective cellular redox homeostasis. This work demonstrates how proteins from the same family have evolved to meet the needs of their hosts.

scholarly journals Single-Nucleotide Polymorphism Phylotyping of Escherichia coli

2005 ◽  
Vol 71 (8) ◽  
pp. 4784-4792 ◽  
Author(s):  
Florence Hommais ◽  
Sabrina Pereira ◽  
Cécile Acquaviva ◽  
Patricia Escobar-Páramo ◽  
Erick Denamur
Keyword(s):  
Escherichia Coli ◽  
Bacterial Species ◽  
Bacterial Genome ◽  
The Other ◽  
Enzyme Electrophoresis ◽  
Phylogenetic Groups ◽  
Single Nucleotide ◽  
E Coli ◽  
Base Extension ◽  
Typing Methods

ABSTRACT We describe a rapid and easily automated phylogenetic grouping technique based on analysis of bacterial genome single-nucleotide polymorphisms (SNPs). We selected 13 SNPs derived from a complete sequence analysis of 11 essential genes previously used for multilocus sequence typing (MLST) of 30 Escherichia coli strains representing the genetic diversity of the species. The 13 SNPs were localized in five genes, trpA, trpB, putP, icdA, and polB, and were selected to allow recovery of the main phylogenetic groups (groups A, B1, E, D, and B2) and subgroups of the species. In the first step, we validated the SNP approach in silico by extracting SNP data from the complete sequences of the five genes for a panel of 65 pathogenic strains belonging to different E. coli pathovars, which were previously analyzed by MLST. In the second step, we determined these SNPs by dideoxy single-base extension of unlabeled oligonucleotide primers for a collection of 183 commensal and extraintestinal clinical E. coli isolates and compared the SNP phylotyping method to previous well-established typing methods. This SNP phylotyping method proved to be consistent with the other methods for assigning phylogenetic groups to the different E. coli strains. In contrast to the other typing methods, such as multilocus enzyme electrophoresis, ribotyping, or PCR phylotyping using the presence/absence of three genomic DNA fragments, the SNP typing method described here is derived from a solid phylogenetic analysis, and the results obtained by this method are more meaningful. Our results indicate that similar approaches may be used for a wide variety of bacterial species.

scholarly journals Prevalence of Legionella spp. and Escherichia coli in the drinking water distribution system of Wrocław (Poland)

2020 ◽  
Vol 20 (3) ◽  
pp. 1083-1090
Author(s):  
M. Wolf-Baca ◽  
A. Siedlecka
Keyword(s):  
Escherichia Coli ◽  
Drinking Water ◽  
Legionella Pneumophila ◽  
Water Samples ◽  
Distribution System ◽  
Water Distribution ◽  
Tap Water ◽  
Potential Threat ◽  
E Coli ◽  
Drinking Water Distribution

Abstract Drinking water should be free from bacterial pathogens that threaten human health. The most recognised waterborne opportunistic pathogens, dwelling in tap water, are Legionella pneumophila and Escherichia coli. Drinking water samples were tested for the presence of Legionella spp., L. pneumophila, and E. coli in overall sample microbiomes using a quantitative real-time polymerase chain reaction (qPCR) approach. The results indicate a rather low contribution of Legionella spp. in total bacteria in the tested samples, but L. pneumophila was not detected in any sample. E. coli was detected in only one sample, but at a very low level. The qacEΔ1 gene, conferring resistance to quaternary ammonium compounds, was also not detected in any sample. The results point to generally sufficient quality of drinking water, although the presence of Legionella spp. in tap water samples suggests proliferation of these bacteria in heating units, causing a potential threat to consumer health.

scholarly journals A Fork Trap in the Chromosomal Termination Area Is Highly Conserved across All Escherichia coli Phylogenetic Groups

2021 ◽  
Vol 22 (15) ◽  
pp. 7928
Author(s):  
Daniel J. Goodall ◽  
Katie H. Jameson ◽  
Michelle Hawkins ◽  
Christian J. Rudolph
Keyword(s):  
Escherichia Coli ◽  
Replication Fork ◽  
Genome Stability ◽  
Bacterial Species ◽  
Physiological Role ◽  
Biochemical Properties ◽  
Phylogenetic Groups ◽  
E Coli ◽  
Evolutionary Advantage ◽  
Bacterial Chromosomes

Termination of DNA replication, the final stage of genome duplication, is surprisingly complex, and failures to bring DNA synthesis to an accurate conclusion can impact genome stability and cell viability. In Escherichia coli, termination takes place in a specialised termination area opposite the origin. A ‘replication fork trap’ is formed by unidirectional fork barriers via the binding of Tus protein to genomic ter sites. Such a fork trap system is found in some bacterial species, but it appears not to be a general feature of bacterial chromosomes. The biochemical properties of fork trap systems have been extensively characterised, but little is known about their precise physiological roles. In this study, we compare locations and distributions of ter terminator sites in E. coli genomes across all phylogenetic groups, including Shigella. Our analysis shows that all ter sites are highly conserved in E. coli, with slightly more variability in the Shigella genomes. Our sequence analysis of ter sites and Tus proteins shows that the fork trap is likely to be active in all strains investigated. In addition, our analysis shows that the dif chromosome dimer resolution site is consistently located between the innermost ter sites, even if rearrangements have changed the location of the innermost termination area. Our data further support the idea that the replication fork trap has an important physiological role that provides an evolutionary advantage.

scholarly journals Inactivation of Nitrosomonas europaea and pathogenic Escherichia coli by chlorine and monochloramine

2008 ◽  
Vol 6 (3) ◽  
pp. 315-322 ◽  
Author(s):  
Christian Chauret ◽  
Curtis Smith ◽  
Hélène Baribeau
Keyword(s):  
Escherichia Coli ◽  
Distribution System ◽  
Distribution Systems ◽  
Pure Water ◽  
Nitrosomonas Europaea ◽  
Inactivation Kinetics ◽  
Soil Material ◽  
E Coli ◽  
Pathogenic Escherichia Coli ◽  
Kinetics Of

The purpose of this study was to measure the chlorine and monochloramine inactivation kinetics of Nitrosomonas europaea at 21°C in the presence and absence of particles. The inactivation kinetics rates were compared with those obtained with Escherichia coli O157:H7. The results show that, in pure water, the use of free chlorine produced 4 log10 of N. europaea inactivation at a CT value of 0.8 mg.min l−1, whereas monochloramine yielded 4 log10 of inactivation at CT values of approximately 9.9–16.4 mg.min l−1. With E. coli, chlorine produced approximately 4 log10 of inactivation at a CT of 0.13 mg.min l−1, whereas monochloramine resulted in 4 log10 of inactivation at a CT of approximately 9.2 mg.min l−1. These results suggest that N. europaea is more resistant to monochloramine and chlorine than E. coli. Corrosion debris, soil material and wastewater had no statistically significant (p < 0.05) impact on the inactivation of N. europaea by either chlorine or monochloramine. It seems likely that the CT values present in distribution systems would be sufficient to control suspended cells of these two organisms, especially under conditions of breakpoint chlorination, which could be used to control nitrification. Adequate disinfection should prevent the growth of these organisms in a distribution system.

scholarly journals Genetic and Phylogenetic Diversity of Escherichia coli Strains Collected From Fecal Specimens of Patients Admitted to Zabol Hospitals

2018 ◽  
Vol 3 (4) ◽  
pp. 154-158
Author(s):  
Aliyeh Firoozkoohi ◽  
Zahra Rashki Ghalehnoo
Keyword(s):  
Escherichia Coli ◽  
Bacterial Species ◽  
Genotypic Diversity ◽  
Biochemical Tests ◽  
Phylogenetic Groups ◽  
E Coli ◽  
Random Amplification ◽  
Group A ◽  
The Difference ◽  
Tract Infections

Introduction: Escherichia coli is one of the most prevalent bacterial species which cause gastrointestinal and digestive tract infections in humans and livestock. This study examined genotypic diversity of the E. coli isolates taken from fecal specimens in Zabol using random amplification of polymorphic DNA (RAPD) method and phylogenetic background.Materials and Methods: In this study, 100 isolates were collected from human samples and identified by the common biochemical tests. The isolates were categorized into four main phylogenetic groups including group A (28 isolates), group B1 (7 isolates), group B2 (48 isolates), and group D (17 isolates). Two primers (H1 & H2) were used to study the genetic variation of E. coli and the electrophoresis band pattern was analyzed by the NTSYS.Results: The analysis of the difference in isolates using the RAPD technique showed a genetic similarity between 14% and 100%.Conclusion: The phylogenetic groups B2 and A were more frequent in fecal isolates. In addition, the number of isolates related to phylogenetic groups B1 and D was significantly lower than that of the other groups.

scholarly journals Antimicrobial Resistance Genes and Diversity of Clones among ESBL- and Acquired AmpC-Producing Escherichia coli Isolated from Fecal Samples of Healthy and Sick Cats in Portugal

Antibiotics ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 262
Author(s):  
Isabel Carvalho ◽  
Nadia Safia Chenouf ◽  
Rita Cunha ◽  
Carla Martins ◽  
Paulo Pimenta ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Public Health Problem ◽  
Phylogenetic Groups ◽  
Disk Diffusion Test ◽  
Extended Spectrum Beta Lactamase ◽  
E Coli ◽  
Specific Pcr ◽  
Flight Mass Spectrometry ◽  
Antimicrobial Resistance Genes ◽  
Esbl Producers

The aim of the study was to analyze the mechanisms of resistance in extended-spectrum beta-lactamase (ESBL)- and acquired AmpC (qAmpC)-producing Escherichia coli isolates from healthy and sick cats in Portugal. A total of 141 rectal swabs recovered from 98 sick and 43 healthy cats were processed for cefotaxime-resistant (CTXR) E. coli recovery (in MacConkey agar supplemented with 2 µg/mL cefotaxime). The matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) method was used for E. coli identification and antimicrobial susceptibility was performed by a disk diffusion test. The presence of resistance/virulence genes was tested by PCR sequencing. The phylogenetic typing and multilocus sequence typing (MLST) were determined by specific PCR sequencing. CTXRE. coli isolates were detected in seven sick and six healthy cats (7.1% and 13.9%, respectively). Based on the synergy tests, 11 of 13 CTXRE. coli isolates (one/sample) were ESBL-producers (ESBL total rate: 7.8%) carrying the following ESBL genes: blaCTX-M-1 (n = 3), blaCTX-M-15 (n = 3), blaCTX-M-55 (n = 2), blaCTX-M-27 (n = 2) and blaCTX-M-9 (n = 1). Six different sequence types were identified among ESBL-producers (sequence type/associated ESBLs): ST847/CTX-M-9, CTX-M-27, CTX-M-1; ST10/CTX-M-15, CTX-M-27; ST6448/CTX-M-15, CTX-M-55; ST429/CTX-M-15; ST101/CTX-M-1 and ST40/CTX-M-1. Three of the CTXR isolates were CMY-2-producers (qAmpC rate: 2.1%); two of them were ESBL-positive and one ESBL-negative. These isolates were typed as ST429 and ST6448 and were obtained in healthy or sick cats. The phylogenetic groups A/B1/D/clade 1 were detected among ESBL- and qAmpC-producing isolates. Cats are carriers of qAmpC (CMY-2)- and ESBL-producing E. coli isolates (mostly of variants of CTX-M group 1) of diverse clonal lineages, which might represent a public health problem due to the proximity of cats with humans regarding a One Health perspective.

scholarly journals Characterization of Escherichia coli Strains Derived from Cow Milk of Subclinical and Clinical Cases of Mastitis

2021 ◽  
Vol 11 (2) ◽  
pp. 541
Author(s):  
Katarzyna Grudlewska-Buda ◽  
Krzysztof Skowron ◽  
Ewa Wałecka-Zacharska ◽  
Natalia Wiktorczyk-Kapischke ◽  
Jarosław Bystroń ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Bacterial Species ◽  
Subclinical Mastitis ◽  
Clinical Mastitis ◽  
Economic Problem ◽  
Cow Milk ◽  
P Value ◽  
Dairy Herds ◽  
E Coli ◽  
Bonferroni Test

Mastitis is a major economic problem in dairy herds, as it might decrease fertility, and negatively affect milk quality and milk yield. Out of over 150 bacterial species responsible for the udder inflammation, Escherichia coli is one of the most notable. This study aimed to assess antimicrobial susceptibility, resistance to dipping agents and biofilm formation of 150 E. coli strains isolated from milk of cows with subclinical and clinical mastitis. The strains came from three dairy herds located in Northern and Central Poland. The statistical analyses were performed with post-hoc Bonferroni test and chi-square test (including Yates correction). The data with a p value of <0.05 were considered significant. We found that the tested strains were mostly sensitive to antimicrobials and dipping agents. It was shown that 37.33% and 4.67% of strains were resistant and moderately resistant to at least one antimicrobial agent, respectively. No extended-spectrum beta-lactamases (ESBL)-producing E. coli were detected. The majority of strains did not possess the ability to form biofilm or formed a weak biofilm. The strong biofilm formers were found only among strains derived from cows with subclinical mastitis. The lowest bacteria number was noted for subclinical mastitis cows’ strains, after stabilization with iodine (3.77 log CFU × cm−2) and chlorhexidine (3.96 log CFU × cm−2) treatment. In the present study, no statistically significant differences in susceptibility to antibiotics and the ability to form biofilm were found among the strains isolated from cows with subclinical and clinical mastitis. Despite this, infections in dairy herds should be monitored. Limiting the spread of bacteria and characterizing the most common etiological factors would allow proper treatment.

scholarly journals Phylogenetic Grouping and Virulence Potential of Extended-Spectrum-β-Lactamase-Producing Escherichia coli Strains in Cattle

2012 ◽  
Vol 78 (13) ◽  
pp. 4677-4682 ◽  
Author(s):  
Charlotte Valat ◽  
Frédéric Auvray ◽  
Karine Forest ◽  
Véronique Métayer ◽  
Emilie Gay ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Virulence Determinants ◽  
Phylogenetic Groups ◽  
Content Type ◽  
E Coli ◽  
Extended Spectrum ◽  
Specific Distribution ◽  
Extended Spectrum Beta Lactamases ◽  
Phylogenetic Grouping ◽  
Almost All

ABSTRACTIn line with recent reports of extended-spectrum beta-lactamases (ESBLs) inEscherichia coliisolates of highly virulent serotypes, such as O104:H4, we investigated the distribution of phylogroups (A, B1, B2, D) and virulence factor (VF)-encoding genes in 204 ESBL-producingE. coliisolates from diarrheic cattle. ESBL genes, VFs, and phylogroups were identified by PCR and a commercial DNA array (Alere, France). ESBL genes belonged mostly to the CTX-M-1 (65.7%) and CTX-M-9 (27.0%) groups, whereas those of the CTX-M-2 and TEM groups were much less represented (3.9% and 3.4%, respectively). One ESBL isolate wasstx1andeaepositive and belonged to a major enterohemorrhagicE. coli(EHEC) serotype (O111:H8). Two other isolates wereeaepositive butstxnegative; one of these had serotype O26:H11. ESBL isolates belonged mainly to phylogroup A (55.4%) and, to lesser extents, to phylogroups D (25.5%) and B1 (15.6%), whereas B2 strains were quasi-absent (1/204). The number of VFs was significantly higher in phylogroup B1 than in phylogroups A (P= 0.04) and D (P= 0.02). Almost all of the VFs detected were found in CTX-M-1 isolates, whereas only 64.3% and 33.3% of them were found in CTX-M-9 and CTX-M-2 isolates, respectively. These results indicated that the widespread dissemination of theblaCTX-Mgenes within theE. colipopulation from cattle still spared the subpopulation of EHEC/Shiga-toxigenicE. coli(STEC) isolates. In contrast to other reports on non-ESBL-producing isolates from domestic animals, B1 was not the main phylogroup identified. However, B1 was found to be the most virulent phylogroup, suggesting host-specific distribution of virulence determinants among phylogenetic groups.

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