scholarly journals Antimicrobial effects of syndiotactic polypeptides

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Prakash Kishore Hazam ◽  
Chimanjita Phukan ◽  
R. Akhil ◽  
Anjali Singh ◽  
Vibin Ramakrishnan
Keyword(s):  
Amino Acids ◽  
Design Space ◽  
Bacterial Species ◽  
Multidrug Resistant ◽  
Model Systems ◽  
Dynamics Simulation ◽  
Simulation Studies ◽  
Molecular Systems ◽  
E Coli ◽  
Present Design

AbstractWe present design and antibacterial studies of stereochemically diversified antimicrobial peptides against multidrug-resistant bacterial pathogens. Syndiotactic polypeptides are polymers of alternating L and D amino acids with LDLD or DLDL backbone stereochemical sequence, which can form stable gramicidin like helical conformations. We designed, synthesized and characterized eight model molecular systems with varied electrostatic fingerprints, modulated through calibrated sequence positioning. Six out of eight model systems showed very impressive antimicrobial activity against three difficult to treat bacterial species, Gentamicin resistant MRSA, E. coli and Mycobacterium. More importantly, the designed LDLD peptides were equally potent in serum, an important drawback of poly L peptide sequences due to enzyme mediated degradation and ion sensitivity. Further, we tested the activity of the designed peptides against drug-resistant clinical isolates of Staphylococcus aureus and Escherichia coli. Molecular dynamics simulation studies suggest formation of an assembly of individual peptides, preceding the membrane interaction and deformation. The activity estimates are comparable with the available peptide based antimicrobials, and are also highly specific and less toxic as per standard estimates. Incorporation of D amino-acids can significantly expand the peptide design space, which can in turn manifest in future biomaterial designs, especially antimicrobials.

scholarly journals Escherichia coli Clonobiome: Assessing the Strain Diversity in Feces and Urine by Deep Amplicon Sequencing

2019 ◽  
Vol 85 (23) ◽  
Author(s):  
Sofiya G. Shevchenko ◽  
Matthew Radey ◽  
Veronika Tchesnokova ◽  
Dagmara Kisiela ◽  
Evgeni V. Sokurenko
Keyword(s):  
Bacterial Species ◽  
Clonal Diversity ◽  
Amplicon Sequencing ◽  
Multidrug Resistant ◽  
Full Understanding ◽  
Highly Pathogenic ◽  
Content Type ◽  
E Coli ◽  
Strain Diversity ◽  
Healthy Carriers

ABSTRACT While microbiome studies have focused on diversity at the species level or higher, bacterial species in microbiomes are represented by different, often multiple, strains. These strains could be clonally and phenotypically very different, making assessment of strain content vital to a full understanding of microbiome function. This is especially important with respect to antibiotic-resistant strains, the clonal spread of which may be dependent on competition between them and susceptible strains from the same species. The pandemic, multidrug-resistant, and highly pathogenic Escherichia coli subclone ST131-H30 (H30) is of special interest, as it has already been found persisting in the gut and bladder in healthy people. In order to rapidly assess E. coli clonal diversity, we developed a novel method based on deep sequencing of two loci used for sequence typing, along with an algorithm for analysis of the resulting data. Using this method, we assessed fecal and urinary samples from healthy women carrying H30 and were able to uncover considerable diversity, including strains with frequencies at <1% of the E. coli population. We also found that, even in the absence of antibiotic use, H30 could completely dominate the gut and, especially, urine of healthy carriers. Our study offers a novel tool for assessing a species’ clonal diversity (clonobiome) within the microbiome, which could be useful in studying the population structure and dynamics of multidrug-resistant and/or highly pathogenic strains in their natural environments. IMPORTANCE Bacterial species in the microbiome are often represented by multiple genetically and phenotypically different strains, making insight into subspecies diversity critical to a full understanding of the microbiome, especially with respect to opportunistic pathogens. However, methods allowing efficient high-throughput clonal typing are not currently available. This study combines a conventional E. coli typing method with deep amplicon sequencing to allow analysis of many samples concurrently. While our method was developed for E. coli, it may be adapted for other species, allowing microbiome researchers to assess clonal strain diversity in natural samples. Since assessment of subspecies diversity is particularly important for understanding the spread of antibiotic resistance, we applied our method to the study of a pandemic multidrug-resistant E. coli clone. The results we present suggest that this clone could be highly competitive in healthy carriers and that the mechanisms of colonization by such clones need to be studied.

scholarly journals Recent Advances in the Surface Functionalization of Nanomaterials for Antimicrobial Applications

Materials ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 6932
Author(s):  
Shahin Shah Khan ◽  
Irfan Ullah ◽  
Sadeeq Ullah ◽  
Ruipeng An ◽  
Haijun Xu ◽  
...  
Keyword(s):  
Surface Functionalization ◽  
Near Infrared ◽  
Biomedical Application ◽  
Bacterial Species ◽  
Multidrug Resistant ◽  
Pathogenic Microorganisms ◽  
Infrared Irradiation ◽  
Oxygen Production ◽  
E Coli ◽  
High Absorption

Innovations in nanotechnology have had an immense impact on medicine, such as in drug delivery, tissue engineering, and medical devices that combat different pathogens. The pathogens that may cause biofilm-associated nosocomial diseases are multidrug-resistant (MDR) bacteria, such as Escherichia coli (E. coli), Pseudomonas aeruginosa (P. aeruginosa), Staphylococcus aureus (S. aureus), including both Gram-positive and Gram-negative bacterial species. About 65–80% of infections are caused by biofilm-associated pathogens creating a move in the international community toward developing antimicrobial therapies to eliminate such pathogenic infections. Several nanomaterials (NMs) have been discovered and significantly employed in various antipathogenic therapies. These NMs have unique properties of singlet oxygen production, high absorption of near-infrared irradiation, and reasonable conversion of light to heat. In this review, functionalized NPs that combat different pathogenic infections are introduced. This review highlights NMs that combat infections caused by multidrug-resistant (MDR) and other pathogenic microorganisms. It also highlights the biomedical application of NPs with regard to antipathogenic activities.

Biofilm Formation by Multidrug-Resistant Salmonella enterica Serotype Typhimurium Phage Type DT104 and Other Pathogens

2007 ◽  
Vol 70 (1) ◽  
pp. 22-29 ◽  
Author(s):  
SHIN-HEE KIM ◽  
CHENG-I WEI
Keyword(s):  
Stainless Steel ◽  
Salmonella Typhimurium ◽  
Salmonella Enterica ◽  
Bacterial Species ◽  
Phage Type ◽  
Meat Products ◽  
Multidrug Resistant ◽  
E Coli ◽  
Retail Meat ◽  
Glass Surfaces

The biofilm-forming capability of Salmonella enterica serotypes Typhimurium and Heidelberg, Pseudomonas aeruginosa, Listeria monocytogenes, Escherichia coli O157:H7, Klebsiella pneumoniae, and Acinetobacter baumannii isolated from humans, animal farms, and retail meat products was evaluated by using a microplate assay. The tested bacterial species showed interstrain variation in their capabilities to form biofilms. Strong biofilm-forming strains of S. enterica serotypes, E. coli O157: H7, P. aeruginosa, K. pneumoniae, and A. baumannii were resistant to at least four of the tested antibiotics. To understand their potential in forming biofilms in food-processing environments, the strong biofilm formers grown in beef, turkey, and lettuce broths were further investigated on stainless steel and glass surfaces. Among the tested strains, Salmonella Typhimurium phage type DT104 (Salmonella Typhimurium DT104) isolated from retail beef formed the strongest biofilm on stainless steel and glass in beef and turkey broths. K. pneumoniae, L. monocytogenes, and P. aeruginosa were also able to form strong biofilms on the tested surface materials. Salmonella Typhimurium DT104 developed a biofilm on stainless steel in beef and turkey broths through (i) initial attachment to the surface, (ii) formation of microcolonies, and (iii) biofilm maturation. These findings indicated that Salmonella Typhimurium DT104 along with other bacterial pathogens could be a source of cross-contamination during handling and processing of food.

scholarly journals Molecular characterization of the TonB2 protein from the fish pathogen Vibrio anguillarum

2009 ◽  
Vol 418 (1) ◽  
pp. 49-59 ◽  
Author(s):  
Claudia S. López ◽  
R. Sean Peacock ◽  
Jorge H. Crosa ◽  
Hans J. Vogel
Keyword(s):  
Amino Acids ◽  
Solution Structure ◽  
Bacterial Species ◽  
Vibrio Anguillarum ◽  
Fish Pathogen ◽  
E Coli ◽  
Terminal Domain ◽  
C Terminus

In the fish pathogen Vibrio anguillarum the TonB2 protein is essential for the uptake of the indigenous siderophore anguibactin. Here we describe deletion mutants and alanine replacements affecting the final six amino acids of TonB2. Deletions of more than two amino acids of the TonB2 C-terminus abolished ferric-anguibactin transport, whereas replacement of the last three residues resulted in a protein with wild-type transport properties. We have solved the high-resolution solution structure of the TonB2 C-terminal domain by NMR spectroscopy. The core of this domain (residues 121–206) has an αββαβ structure, whereas residues 76–120 are flexible and extended. This overall folding topology is similar to the Escherichia coli TonB C-terminal domain, albeit with two differences: the β4 strand found at the C-terminus of TonB is absent in TonB2, and loop 3 is extended by 9 Å (0.9 nm) in TonB2. By examining several mutants, we determined that a complete loop 3 is not essential for TonB2 activity. Our results indicate that the β4 strand of E. coli TonB is not required for activity of the TonB system across Gram-negative bacterial species. We have also determined, through NMR chemical-shift-perturbation experiments, that the E. coli TonB binds in vitro to the TonB box from the TonB2-dependent outer membrane transporter FatA; moreover, it can substitute in vivo for TonB2 during ferric-anguibactin transport in V. anguillarum. Unexpectedly, TonB2 did not bind in vitro to the FatA TonB-box region, suggesting that additional factors may be required to promote this interaction. Overall our results indicate that TonB2 is a representative of a different class of TonB proteins.

scholarly journals Routine Intraoperative Bacterial Culture May Be Needed in Complicated Appendicitis

2020 ◽  
Vol 36 (3) ◽  
pp. 155-162
Author(s):  
Jung Tack Son ◽  
Gue Chun Lee ◽  
Hyung Ook Kim ◽  
Taewoon Kim ◽  
Donghyoun Lee ◽  
...  
Keyword(s):  
Bacterial Species ◽  
Multidrug Resistant ◽  
Resistance Rate ◽  
Complicated Appendicitis ◽  
Resistant Bacteria ◽  
Extended Spectrum Beta Lactamase ◽  
E Coli ◽  
Positive Rate ◽  
Antibiotics Susceptibility ◽  
Resistance Rates

Purpose: Choosing the appropriate antibiotic is important for treatment of complicated appendicitis. However, increasing multidrug resistant bacteria have been a serious problem for successful treatment. This study was designed to identify bacteria isolated from patients with complicated appendicitis and reveal their susceptibilities for antibiotics and their relationship with patient clinical course.Methods: This study included patients diagnosed with complicated appendicitis and examined the bacterial cultures and antimicrobial susceptibilities of the isolates. Data were retrospectively collected from medical records of Kangbuk Samsung Hospital from January 2008 to February 2018.Results: The common bacterial species cultured in complicated appendicitis were as follows: <i>Escherichia coli</i> (n=113, 48.9%), <i>Streptococcus</i> spp. (n=29, 12.6%), <i>Pseudomonas</i> spp. (n=23, 10.0%), <i>Bacteriodes</i> spp. (n=22, 9.5%), <i>Klebsiella</i> (n=11, 4.8%), and <i>Enterococcus</i> spp. (n=8, 3.5%). In antibiotics susceptibility testing, the positive rate of extended-spectrum beta lactamase (ESBL) was 9.1% (21 of 231). The resistance rate to carbapenem was 1.7% (4 of 231), while that to vancomycin was 0.4% (1 of 231). <i>E. coli</i> was 16.8% ESBL positive (19 of 113) and had 22.1% and 19.5% resistance rates to cefotaxime and ceftazidime, respectively. Inappropriate empirical antibiotic treatment (IEAT) occurred in 55 cases (31.8%) and was significantly related with organ/space surgical site infection (SSI) (7 of 55, P=0.005).Conclusion: The rate of antibiotic resistance organisms was high in community-acquired complicated appendicitis in Koreans. Additionally, IEAT in complicated appendicitis may lead to increased rates of SSI. Routine intraoperative culture in patients with complicated appendicitis may be an effective strategy for appropriate antibiotic regimen.

Effect of bacteria on the inactivation and adsorption on clay minerals of reovirus

1985 ◽  
Vol 31 (8) ◽  
pp. 730-735 ◽  
Author(s):  
Steven M. Lipson ◽  
G. Stotzky
Keyword(s):  
Tissue Culture ◽  
Antiviral Activity ◽  
Clay Minerals ◽  
Bacterial Species ◽  
Model Systems ◽  
Live Cells ◽  
Virus Concentration ◽  
E Coli ◽  
Infective Dose ◽  
Culture Supernatants

This investigation studied the antiviral activity of, and the utilization of viruses as substrates by, bacteria. Reovirus type 3 and bacterial species representative of those endemic to sewage, aquatic, and terrestrial habitats were used in the model systems. Culture supernatants from Bacillus subtilis maintained for 5 days in a minimal salts medium displayed antiviral activity, but supernatants from Escherichia coli or Serratia marcescens did not. Both live and toluene-killed cells reduced the inactivation of reovirus during 4 days of incubation at 23 ± 2 °C. This protective effect was more pronounced with killed than with live cells of B. subtilis, confirming the presence of an antiviral component(s) in this species and indicating that the component(s) was metabolic in origin. When reovirus was presented to these bacteria as a sole source of carbon, some growth (determined spectrophotometrically) of B. subtilis and S. marcescens occurred with reovirus concentrations of 3.1 × 106 and 8.2 × 106 mean tissue culture infective dose-fifty∙mL−1, respectively. Growth of S. marcescens did not occur with a reovirus concentration of 8.0 × 104 mean tissue culture infective dose-fifty∙mL−1, nor did that of E. coli with any virus concentration used in this study. Adsorption of reovirus on kaolinite was enhanced by the culture supernatant from S. marcescens and on montmorillonite, albeit to a lesser extent, by that from E. coli. The effect of culture supernatants from B. subtilis on the adsorption of reovirus on clay minerals could not be determined, as a result of the antiviral component produced by these cells. The virus was not adsorbed on the bacteria.

Synthesis of the tetrasaccharide repeating unit of the O-antigen of the Escherichia coli O69 strain and its conformational analysis

RSC Advances ◽  
2014 ◽  
Vol 4 (70) ◽  
pp. 37079-37084 ◽  
Author(s):  
Manas Jana ◽  
Rajiv Kumar Kar ◽  
Anirban Bhunia ◽  
Anup Kumar Misra
Keyword(s):  
Escherichia Coli ◽  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Conformational Analysis ◽  
Dynamics Simulation ◽  
Two Dimensional ◽  
Simulation Studies ◽  
One Pot ◽  
E Coli ◽  
O Antigen

A tetrasaccharide corresponding to theO-antigen of theE. coliO69 strain has been synthesized using iterative glycosylations in one pot. The conformational analysis of the tetrasaccharide was carried out using two-dimensional ROESY spectroscopy and molecular dynamics simulation studies.

scholarly journals First isolation of atypical enteropathogenic Escherichia coli from geese (Anser anser domestica) and first description of atypical EPEC from turkeys and pigeons in Hungary

2021 ◽  
Vol 17 (1) ◽  
Author(s):  
András Adorján ◽  
Ákos Thuma ◽  
László Könyves ◽  
István Tóth
Keyword(s):  
Escherichia Coli ◽  
Bacterial Species ◽  
Age Groups ◽  
Multidrug Resistant ◽  
Growing Up ◽  
Anser Anser ◽  
E Coli ◽  
Atypical Epec ◽  
Chicken Farm ◽  
Backyard Chicken

Abstract Background Escherichia coli is a bacterial species widely distributed among mammals and avian species, and also a member of the normal intestinal microbiota. However, some E. coli strains of different pathotypes can cause disease in both humans and animals. Atypical enteropathogenic E. coli (aEPEC) can infect both animals and humans or influence the severity of other ongoing infections. Results In the present study, a total of 332 samples were collected from ducks, geese, turkeys, chickens, and pigeons from the Hungarian Veterinary Diagnostic Directorate, two slaughterhouses, two pigeon keepers and one backyard chicken farm. E. coli was isolated and verified from 319 samples. The isolates were screened by PCR for diarrheagenic E. coli pathotypes. Altogether seven atypical enteropathogenic E. coli (aEPEC) strains were identified: two from four-week-old dead turkeys, two from force-fed geese, and three from pigeons. No further pathotypes were identified in the collection. The atypical EPEC strains were classified phylogenetically to B1, B2, and F, and four out of the seven aEPEC isolates proved to be multidrug resistant. Serotypes of aEPEC strains were uniform collected from same farms and showed diversity between their origins with O76, O145, O109 serogroups. Conclusions This is the first report in the literature about aEPEC in goose (Anser anser domestica). Furthermore, this is the first isolation of aEPEC from turkeys and pigeons in Hungary. The uneven distribution of aEPEC in different age groups of poultry suggests that aEPEC disappears with growing up, but stress (e.g.: force-feeding) and concurrent diseases might promote its reappearance in the intestine.

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