scholarly journals Identification and characterization of pathogenic E. coli -specific bacteriophages and polyvalent bacteriophages in piglet gut with increasing coliphage numbers after weaning

2021 ◽  
Author(s):  
Yan Lin ◽  
Bei Zhou ◽  
Weiyun Zhu
Keyword(s):  
Bacterial Communities ◽  
Biological Significance ◽  
Metagenomic Sequencing ◽  
Biological Characterization ◽  
E Coli ◽  
Intestinal Physiology ◽  
Faecal Samples ◽  
Pig Farms ◽  
Identification And Characterization

Post-weaning diarrhoea in pigs is mainly caused by pathogenic Escherichia coli and is a major source of revenue loss to the livestock industry. Bacteriophages dominate the gut virome and have the potential to regulate bacterial communities and thus influence the intestinal physiology. To determine the biological characterization of intestinal coliphages, we isolated and identified the faecal coliphages of healthy pre-weaned and post-weaned piglets from Nanjing and Chuzhou pig farms. First, ahead of coliphage isolation, 87 E. coli strains were isolated from healthy or diarrheal faecal samples from three pig farms, of which 8 were pathogenic strains including ETEC and EPEC. 87.3% of E. coli strains possessed drug resistance against three antibiotics. Using these 87 E. coli strains as indicator hosts, we isolated 45 coliphages and found a higher presence in the post-weaning stage than pre-weaning stage (24 vs 17 in Nanjing farm, 13 vs 4 in Chuzhou farm). Further more, each farm had a one most prevalent coliphage strain. Pathogenic E. coli -specific bacteriophages were commonly detected (9/10 samples in Nanjing farm, 7/10 in Chuzhou farm) in guts of sampled piglet and most had significant bacteriostatic effects ( P < 0.05) on pathogenic E. coli strains. Three polyvalent bacteriophages (N24, N30, and C5) were identified. The N30 and C5 strains showed a genetic identity of 89.67% with mild differences in infection characteristics. Our findings suggest that pathogenic E. coli -specific bacteriophages as well as polyvalent bacteriophages are commonly present in piglet gut and that weaning is an important event that affects coliphage numbers. IMPORTANCE Previous studies based on metagenomic sequencing reported that gut bacteriophages profoundly influence gut physiology but did not provide information regarding the host range and biological significance. Here, we screened coliphages from pre-weaned and post-weaned piglet gut against indicator hosts, which allowed us to identify the pathogenic E. coli -specific bacteriophages and polyvalent bacteriophages in pig farms and quantify their presence. Our approach complements sequencing methods and provides new insights into the biological characterizations of bacteriophage in the gut along with the ecological effects of intestinal bacteriophages.

scholarly journals Isolation and characterization of escherichia coli in ready-to-eat foods vended in Islamic University, Kushtia

1970 ◽  
Vol 18 ◽  
pp. 99-103 ◽  
Author(s):  
S Biswas ◽  
MAK Parvez ◽  
M Shafiquzzaman ◽  
S Nahar ◽  
MN Rahman
Keyword(s):  
Escherichia Coli ◽  
Pattern Analysis ◽  
University Campus ◽  
Rflp Pattern ◽  
E Coli ◽  
Fish Meat ◽  
Isolation And Characterization ◽  
Food Borne ◽  
Identification And Characterization

Context: Escherichia coli is shed in the feces of warm blooded animals and humans and thus potential for public health. Detection and characterization of E. coli in the ready-to-eat (RTE) foods concerns due to their presence indicates fecal contamination of the food.   Objective: To identify, characterize and RFLP pattern analysis of E. coli isolated from RTE foods vended in Islamic University campus, Kushtia.   Materials and Methods: Fifty samples from four types of consumed foods in six student halls of residence, some temporary restaurants of Islamic University, Kushtia were assessed for bacterial contamination by standard methods. Identification and characterization of E. coli isolates were performed using IMViC tests. Genomic DNA was used to perform RFLP pattern analysis.   Results: Thirty seven out of 50 (74%) examined samples of RTE foods had E. coli contamination. The highest number of E. coli was isolated from vegetable oriented RTE foods (90.90%) and fish, meat and cereals samples were also significantly E. coli positive. RFLP profiling of two E. coli isolates were observed.   Conclusion: The results of this study provide evidence that some RTE foods had unsatisfactory levels of contamination with E. coli. Thus street vended RTE food could be important potential vehicles for food-borne diseases. Molecular characterization may be exploited to identify food borne pathogen among different species.  Keywords: Ready-to-eat foods; Escherichia coli; RFLP pattern DOI: http://dx.doi.org/10.3329/jbs.v18i0.8783 JBS 2010; 18(0): 99-103

Identification and characterization of four new tra cistrons on the E. coli K12 sex factor F

Plasmid ◽  
1978 ◽  
Vol 1 (3) ◽  
pp. 316-323 ◽  
Author(s):  
T. Miki ◽  
T. Horiuchi ◽  
N.S. Willetts
Keyword(s):  
E Coli ◽  
Identification And Characterization

scholarly journals Postgenomic Scan of Metallo-β-Lactamase Homologues in Rhizobacteria: Identification and Characterization of BJP-1, a Subclass B3 Ortholog from Bradyrhizobium japonicum

2006 ◽  
Vol 50 (6) ◽  
pp. 1973-1981 ◽  
Author(s):  
Magdalena Stoczko ◽  
Jean-Marie Frère ◽  
Gian Maria Rossolini ◽  
Jean-Denis Docquier
Keyword(s):  
Bradyrhizobium Japonicum ◽  
Catalytic Efficiency ◽  
Open Reading Frames ◽  
Human Pathogens ◽  
Microbial Genomes ◽  
E Coli ◽  
Genes Encoding ◽  
And Function ◽  
Identification And Characterization

ABSTRACT The diffusion of metallo-β-lactamases (MBLs) among clinically important human pathogens represents a therapeutic issue of increasing importance. However, the origin of these resistance determinants is largely unknown, although an important number of proteins belonging to the MBL superfamily have been identified in microbial genomes. In this work, we analyzed the distribution and function of genes encoding MBL-like proteins in the class Rhizobiales. Among 12 released complete genomes of members of the class Rhizobiales, a total of 57 open reading frames (ORFs) were found to have the MBL conserved motif and identity scores with MBLs ranging from 8 to 40%. On the basis of the best identity scores with known MBLs, four ORFs were cloned into Escherichia coli for heterologous expression. Among their products, one (blr6230) encoded by the Bradyrhizobium japonicum USDA110 genome, named BJP-1, hydrolyzed β-lactams when expressed in E. coli. BJP-1 enzyme is most closely related to the CAU-1 enzyme from Caulobacter vibrioides (40% amino acid sequence identity), a member of subclass B3 MBLs. A kinetic analysis revealed that BJP-1 efficiently hydrolyzed most β-lactam substrates, except aztreonam, ticarcillin, and temocillin, with the highest catalytic efficiency measured with meropenem. Compared to other MBLs, BJP-1 was less sensitive to inactivation by chelating agents.

scholarly journals Frequency of Detection ofEscherichia coli,Salmonellaspp., andCampylobacterspp. in the Faeces of Wild Rats (Rattusspp.) in Trinidad and Tobago

2011 ◽  
Vol 2011 ◽  
pp. 1-7 ◽  
Author(s):  
Comfort Nkogwe ◽  
Juliah Raletobana ◽  
Alva Stewart-Johnson ◽  
Sharianne Suepaul ◽  
Abiodun Adesiyun
Keyword(s):  
Antimicrobial Agents ◽  
Diffusion Method ◽  
Disc Diffusion ◽  
Macconkey Agar ◽  
Disc Diffusion Method ◽  
O157 Strain ◽  
E Coli ◽  
Faecal Samples ◽  
Wild Rats

The study was conducted to determine the frequency of isolation ofSalmonella,CampylobacterandE. coliO157 in the faecal samples of rats trapped across the regional corporations in Trinidad and to assess their resistance to antimicrobial agents. A total of 204 rats were trapped for the detection of selected bacteria. Standard methods were used to isolateSalmonella,CampylobacterandE. coliO157. Characterization ofE. coliwas done on sorbitol MacConkey agar to determine non-sorbitol fermentation, blood agar to determine haemolytic and mucoid colonies and by usingE. coliO157 antiserum to determine O157 strain. The disc diffusion method was used to determine resistance to nine antimicrobial agents. Of the 204 rats, 4 (2.0%), 7 (3.4%) and 171 (83.8%) were positive forSalmonellaspp.,Campylobacterspp. andE. coli, respectively. Of the 171 isolates ofE. colitested 0 (0.0%), 25 (14.6%) and 19 (11.1%) were haemolytic, mucoid and non-sorbitol fermenters, respectively. All isolates were negative for the O157 strain. The frequency of resistance to the 9 antimicrobial agents tested was 75% (3 of 4) forSalmonella, 85.7% (6 of 7) ofCampylobacterspp. and 36.3% (62 of 171) forE. coli(;χ2).

scholarly journals Identification and characterization of novel porcine astroviruses (PAstVs) with high prevalence and frequent co-infection of individual pigs with multiple PAstV types

2013 ◽  
Vol 94 (3) ◽  
pp. 570-582 ◽  
Author(s):  
Chao-Ting Xiao ◽  
Luis G. Giménez-Lirola ◽  
Priscilla F. Gerber ◽  
Yong-Hou Jiang ◽  
Patrick G. Halbur ◽  
...  
Keyword(s):  
Zoonotic Potential ◽  
The Novel ◽  
Extraintestinal Manifestations ◽  
Faecal Samples ◽  
High Prevalence ◽  
The Usa ◽  
History Of ◽  
Identification And Characterization ◽  
Sequence Identities

Many astrovirus (AstV) species are associated with enteric disease, although extraintestinal manifestations in mammalian and avian hosts have also been described. In this study, the prevalence rates of porcine AstV types 1–5 (PAstV1–PAstV5) were investigated using faecal samples from 509 pigs of which 488 (95.9 %) came from farms with a history of diarrhoea. All of the five known PAstV types were found to circulate in pigs in the USA, and co-infection of a single pig with two or more PAstV types was frequently observed. A high overall prevalence of 64.0 % (326/509) of PAstV RNA-positive samples was detected, with 97.2 % (317/326) of the PAstV RNA-positive pigs infected with PAstV4. Further genomic sequencing and characterization of the selected isolates revealed low sequence identities (49.2–89.0 %) with known PAstV strains, indicating novel types or genotypes of PAstV2, PAstV4 and PAstV5. Some new features of the genomes of the PAstVs were also discovered. The first complete genome of a PAstV3 isolate was obtained and showed identities of 50.5–55.3 % with mink AstV and the novel human AstVs compared with 38.4–42.7 % with other PAstV types. Phylogenetic analysis revealed that PAstV1, PAstV2 and PAstV3 were more closely related to AstVs from humans and other animals than to each other, indicating past cross-species transmission and the zoonotic potential of these PAstVs.

scholarly journals Identification and Characterization of an Archaeon-Specific Riboflavin Kinase

2008 ◽  
Vol 190 (7) ◽  
pp. 2615-2618 ◽  
Author(s):  
Zahra Mashhadi ◽  
Hong Zhang ◽  
Huimin Xu ◽  
Robert H. White
Keyword(s):  
Escherichia Coli ◽  
Metal Ion ◽  
Biosynthetic Pathway ◽  
Recombinant Expression ◽  
Cell Extract ◽  
Flavin Mononucleotide ◽  
E Coli ◽  
Gene Recombinant ◽  
Identification And Characterization

ABSTRACT The riboflavin kinase in Methanocaldococcus jannaschii has been identified as the product of the MJ0056 gene. Recombinant expression of the MJ0056 gene in Escherichia coli led to a large increase in the amount of flavin mononucleotide (FMN) in the E. coli cell extract. The unexpected features of the purified recombinant enzyme were its use of CTP as the phosphoryl donor and the absence of a requirement for added metal ion to catalyze the formation of FMN. Identification of this riboflavin kinase fills another gap in the archaeal flavin biosynthetic pathway. Some divalent metals were found to be potent inhibitors of the reaction. The enzyme represents a unique CTP-dependent family of kinases.

scholarly journals Identification and Characterization of a New Lipoprotein, NlpI, in Escherichia coli K-12

1999 ◽  
Vol 181 (14) ◽  
pp. 4318-4325 ◽  
Author(s):  
Masaru Ohara ◽  
Henry C. Wu ◽  
Krishnan Sankaran ◽  
Paul D. Rick
Keyword(s):  
Escherichia Coli ◽  
Direct Consequence ◽  
Insertion Mutant ◽  
Polynucleotide Phosphorylase ◽  
Wild Type ◽  
E Coli ◽  
K 12 ◽  
Identification And Characterization ◽  
Lines Of Evidence

ABSTRACT We report here the identification of a new lipoprotein, NlpI, inEscherichia coli K-12. The NlpI structural gene (nlpI) is located between the genes pnp(polynucleotide phosphorylase) and deaD (RNA helicase) at 71 min on the E. coli chromosome. The nlpI gene encodes a putative polypeptide of approximately 34 kDa, and multiple lines of evidence clearly demonstrate that NlpI is indeed a lipoprotein. An nlpI::cm mutation rendered growth of the cells osmotically sensitive, and incubation of the insertion mutant at an elevated temperature resulted in the formation of filaments. The altered phenotype of the mutant was a direct consequence of the mutation in nlpI, since it was complemented by the wild-type nlpI gene alone. Overexpression of the unaltered nlpI gene in wild-type cells resulted in the loss of the rod morphology and the formation of single prolate ellipsoids and pairs of prolate ellipsoids joined by partial constrictions. NlpI may be important for an as-yet-undefined step in the overall process of cell division.

scholarly journals Prevalence and characterization of multi-drug resistant Escherichia coli from urine samples

1970 ◽  
Vol 20 (1) ◽  
pp. 23-30
Author(s):  
Augustin Kakon Gomes ◽  
Humaira Akhter ◽  
Belal Mahmud ◽  
Sirajul Islam Khan ◽  
Anowara Begum
Keyword(s):  
Escherichia Coli ◽  
Urinary Tract Infection ◽  
Profile Analysis ◽  
Plasmid Profile ◽  
Urine Samples ◽  
Drug Resistant ◽  
Methyl Red ◽  
E Coli ◽  
Identification And Characterization

Isolation, identification and characterization of Escherichia coli were carried out in terms of biochemical, serological, antibiogram, plasmid profile and culture condition of urine samples. Out of 50 urine samples, 36 were positive for E. coli that were confirmed by biochemical (e.g. oxidase, kligler’s iron agar, indole, methyl red-voges proskauer and citrate utilization) tests and 4-methyl-umbelliferyl-β-D-glucoronide (MUG) test. Twenty seven strains gave positive result with different antisera whereas nine strains were untypable (UT), respectively. Thirty six strains were also tested by antibiogram against ten different antibiotics. Most E. coli strains were resistant to bacitracin, ampicillin, novobiocin, kanamycin and streptomycin. Eighty three per cent strains were sensitive to ciprofloxacin and gentamycin while 11 and 12% showed resistance to ciprofloxacin and gentamycin, respectively. By plasmid profile analysis of the 36 strains seven different plasmid patterns were observed. Comparison of the plasmid profiles with the antibiogram results indicated the presence of resistant (R) plasmid. Thirty four isolates of E. coli contained a common 25 kb plasmid that may possibly be responsible for drug resistance in this study. The results suggested that the prevalence of multi-drug resistant and new serotype of E. coli may be increasing rapidly which is alarming for treatment of urinary tract infection in Bangladesh.Key words: Prevalence; Characterization; E. coli; Multi-drug resistant; Serotype; Clinical sampleDOI: http://dx.doi.org/10.3329/dujbs.v20i1.8834Dhaka Univ. J. Biol. Sci. 20(1): 23-30, 2011 (January)

scholarly journals Two bacterial glycosphingolipid synthases responsible for the synthesis of glucuronosylceramide and α-galactosylceramide

2020 ◽  
Vol 295 (31) ◽  
pp. 10709-10725
Author(s):  
Nozomu Okino ◽  
Mengbai Li ◽  
Qingjun Qu ◽  
Tomoko Nakagawa ◽  
Yasuhiro Hayashi ◽  
...  
Keyword(s):  
Gel Filtration ◽  
Homologous Gene ◽  
Bacterial Physiology ◽  
E Coli ◽  
Donor And Acceptor ◽  
Low Levels ◽  
Killer T Cells ◽  
Invariant Natural Killer ◽  
Identification And Characterization

Bacterial glycosphingolipids such as glucuronosylceramide and galactosylceramide have been identified as ligands for invariant natural killer T cells and play important roles in host defense. However, the glycosphingolipid synthases required for production of these ceramides have not been well-characterized. Here, we report the identification and characterization of glucuronosylceramide synthase (ceramide UDP-glucuronosyltransferase [Cer-GlcAT]) in Zymomonas mobilis, a Gram-negative bacterium whose cellular membranes contain glucuronosylceramide. On comparing the gene sequences that encode the diacylglycerol GlcAT in bacteria and plants, we found a homologous gene that is widely distributed in the order Sphingomonadales in the Z. mobilis genome. We first cloned the gene and expressed it in Escherichia coli, followed by protein purification using nickel–Sepharose affinity and gel filtration chromatography. Using the highly enriched enzyme, we observed that it has high glycosyltransferase activity with UDP-glucuronic acid and ceramide as sugar donor and acceptor substrate, respectively. Cer-GlcAT deletion resulted in a loss of glucuronosylceramide and increased the levels of ceramide phosphoglycerol, which was expressed in WT cells only at very low levels. Furthermore, we found sequences homologous to Cer-GlcAT in Sphingobium yanoikuyae and Bacteroides fragilis, which have been reported to produce glucuronosylceramide and α-galactosylceramide, respectively. We expressed the two homologs of the cer-glcat gene in E. coli and found that each gene encodes Cer-GlcAT and Cer-galactosyltransferase, respectively. These results contribute to the understanding of the roles of bacterial glycosphingolipids in host–bacteria interactions and the function of bacterial glycosphingolipids in bacterial physiology.

scholarly journals Molecular Characterization of Antimicrobial Resistance in Escherichia coli from Rabbit Farms in Tai’an, China

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Xiaonan Zhao ◽  
Jie Yang ◽  
Zijing Ju ◽  
Weishan Chang ◽  
Shuhong Sun
Keyword(s):  
Escherichia Coli ◽  
Gene Cassette ◽  
Human Medicine ◽  
Class I ◽  
E Coli ◽  
Faecal Samples ◽  
Class I Integrons ◽  
Reasonable Use ◽  
Sequence Types

To investigate the prevalence and resistance against antimicrobials of Escherichia coli (E. coli) in Tai’an, March 2016, a total of 55 E. coli strains were isolated from 60 faecal samples of diarrheic rabbits collected from three rabbit farms in Tai’an. The E. coli isolates were assayed for antimicrobial susceptibility and prevalence of resistance genes and Class I integrons and genotyped using Multilocus Sequence Typing (MLST). All the E. coli isolates were sensitive to ceftazidime, ceftriaxone, imipenem, and amikacin, while 78.2% of the isolates showed resistance against tetracycline, and 65.5% were resistant against ampicillin. The most common resistance gene detected was blaTEM, present in 98.2% of isolates, followed by blaCTX-M (94.6%) and sul2 (58.2%). Class I integrons were detected in 17 out of the 55 (30.9%) E. coli strains. Seven kinds of gene cassette were detected: dfrA17 + aadA5, dfrA1 + catB3 + aacA4, aadA2 + LinF, dfrA1 + aadA1, aadA22, dfrA12 + orfF + addA2, and aadA16 + dfrA27 + arr-3. All the 55 E. coli strains were identified and classified as 13 sequence types (STs); ST302 (22/55, 40.0%) was the most prevalent type, followed by ST370 (12/55, 21.8%). This study showed that E. coli isolated from diarrheic farmed rabbits in the Tai’an area exhibit sometimes very frequent resistance to antimicrobials important to human medicine, which further highlights the need for reasonable use of antibiotics.

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