A PHP Error was encountered

Severity: Warning

Message: file_get_contents(https://...@pubfacts.com&api_key=b8daa3ad693db53b1410957c26c9a51b4908&a=1): Failed to open stream: HTTP request failed! HTTP/1.1 429 Too Many Requests

Filename: helpers/my_audit_helper.php

Line Number: 176

Backtrace:

File: /var/www/html/application/helpers/my_audit_helper.php
Line: 176
Function: file_get_contents

File: /var/www/html/application/helpers/my_audit_helper.php
Line: 250
Function: simplexml_load_file_from_url

File: /var/www/html/application/helpers/my_audit_helper.php
Line: 1034
Function: getPubMedXML

File: /var/www/html/application/helpers/my_audit_helper.php
Line: 3152
Function: GetPubMedArticleOutput_2016

File: /var/www/html/application/controllers/Detail.php
Line: 575
Function: pubMedSearch_Global

File: /var/www/html/application/controllers/Detail.php
Line: 489
Function: pubMedGetRelatedKeyword

File: /var/www/html/index.php
Line: 316
Function: require_once

Combination of guanidinium and quaternary ammonium polymers with distinctive antimicrobial mechanisms achieving a synergistic antimicrobial effect. | LitMetric

The increasing emergence and spread of antimicrobial resistance are urgent and important global challenges today. The clinical pipeline is lacking in innovative drugs that avoid the development of drug resistance. Macromolecular antimicrobials kill bacteria and fungi through physical disruptions to the cell membrane, which is difficult for microbes to overcome. Recently, we reported antimicrobial polycarbonates that kill microbes via two different mechanisms. Polycarbonates functionalized with quaternary ammonium disrupted the lipid bilayer membrane of the microbes, while polycarbonates functionalized with guanidinium translocated the membrane and precipitated cytosolic components. We hypothesized that the combination of these two distinct mechanisms would result in a more than additive increase in antimicrobial efficacy. Block and random copolymers containing both cationic groups had similar minimum inhibitory concentrations (MICs) as the guanidinium homopolymer on 5 representatives of the ESKAPE pathogens. Interestingly, the random copolymer killed P. aeruginosa and A. baumannii more rapidly than the block copolymer and the guanidinium homopolymer with the same number of guanidinium groups. Like quaternary ammonium homopolymer, the copolymers killed the bacteria via a membrane-disruptive mechanism. Then, we simply mixed quaternary ammonium homopolymer and guanidinium homopolymer, and studied antimicrobial activity of the combination at various concentrations. Checkerboard assay results showed that the combination of the polymers, in general, achieved a synergistic or additive effect in inhibiting the growth of bacteria. At concentrations where it exibited a synergistic or additive effect in inhibiting bacterial growth, the combination killed the bacteria effectively (99%-99.9% killing efficiency) although the individual polymers at these concentrations did not exert bactericidal activity. Therefore, it is essential to have the two functional groups on separate molecules to provide synergism. This study provides a basic understanding of polymer design with different cationic groups.

Download full-text PDF

Source
http://dx.doi.org/10.1039/d0bm00752hDOI Listing

Publication Analysis

Top Keywords

quaternary ammonium
16
guanidinium homopolymer
12
polycarbonates functionalized
8
cationic groups
8
ammonium homopolymer
8
killed bacteria
8
synergistic additive
8
additive inhibiting
8
antimicrobial
6
combination
5

Similar Publications

Want AI Summaries of new PubMed Abstracts delivered to your In-box?

Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!