scholarly journals Polyphenylglyoxamide-Based Amphiphilic Small Molecular Peptidomimetics as Antibacterial Agents with Anti-Biofilm Activity

2021 ◽  
Vol 22 (14) ◽  
pp. 7344
Author(s):  
Tsz Tin Yu ◽  
Rajesh Kuppusamy ◽  
Muhammad Yasir ◽  
Md. Musfizur Hassan ◽  
Manjulatha Sara ◽  
...  
Keyword(s):  
Quaternary Ammonium ◽  
Antibacterial Agents ◽  
Health Concern ◽  
Resistant Bacteria ◽  
Ammonium Iodide ◽  
E Coli ◽  
Drug Resistant Bacteria ◽  
Permeability Study ◽  
Cationic Group ◽  
Chain Lengths

The rapid emergence of drug-resistant bacteria is a major global health concern. Antimicrobial peptides (AMPs) and peptidomimetics have arisen as a new class of antibacterial agents in recent years in an attempt to overcome antibiotic resistance. A library of phenylglyoxamide-based small molecular peptidomimetics was synthesised by incorporating an N-alkylsulfonyl hydrophobic group with varying alkyl chain lengths and a hydrophilic cationic group into a glyoxamide core appended to phenyl ring systems. The quaternary ammonium iodide salts 16d and 17c showed excellent minimum inhibitory concentration (MIC) of 4 and 8 μM (2.9 and 5.6 μg/mL) against Staphylococcus aureus, respectively, while the guanidinium hydrochloride salt 34a showed an MIC of 16 μM (8.5 μg/mL) against Escherichia coli. Additionally, the quaternary ammonium iodide salt 17c inhibited 70% S. aureus biofilm formation at 16 μM. It also disrupted 44% of pre-established S. aureus biofilms at 32 μM and 28% of pre-established E. coli biofilms 64 μM, respectively. A cytoplasmic membrane permeability study indicated that the synthesised peptidomimetics acted via disruption and depolarisation of membranes. Moreover, the quaternary ammonium iodide salts 16d and 17c were non-toxic against human cells at their therapeutic dosages against S. aureus.

scholarly journals Mechanistic Insights into the Antimicrobial Actions of Metallic Nanoparticles and Their Implications for Multidrug Resistance

2019 ◽  
Vol 20 (10) ◽  
pp. 2468 ◽  
Author(s):  
Sibhghatulla Shaikh ◽  
Nazia Nazam ◽  
Syed Mohd Danish Rizvi ◽  
Khurshid Ahmad ◽  
Mohammad Hassan Baig ◽  
...  
Keyword(s):  
Metallic Nanoparticles ◽  
Bacterial Infections ◽  
Antibacterial Agents ◽  
Health Concern ◽  
Resistant Bacteria ◽  
Multiple Drug ◽  
Drug Resistant ◽  
Drug Resistant Bacteria ◽  
Multiple Drug Resistant ◽  
Bacterial Drug Resistance

Multiple drug-resistant bacteria are a severe and growing public health concern. Because relatively few antibiotics have been approved over recent years and because of the inability of existing antibiotics to combat bacterial infections fully, demand for unconventional biocides is intense. Metallic nanoparticles (NPs) offer a novel potential means of fighting bacteria. Although metallic NPs exert their effects through membrane protein damage, superoxide radicals and the generation of ions that interfere with the cell granules leading to the formation of condensed particles, their antimicrobial potential, and mechanisms of action are still debated. This article discusses the action of metallic NPs as antibacterial agents, their mechanism of action, and their effect on bacterial drug resistance. Based on encouraging data about the antibacterial effects of NP/antibiotic combinations, we propose that this concept be thoroughly researched to identify means of combating drug-resistant bacteria.

scholarly journals Analogues of a Cyclic Antimicrobial Peptide with a Flexible Linker Show Promising Activity against Pseudomonas aeruginosa and Staphylococcus aureus

Antibiotics ◽  
2020 ◽  
Vol 9 (7) ◽  
pp. 366 ◽  
Author(s):  
Thomas Thomsen ◽  
Helen Mendel ◽  
Wafaa Al-Mansour ◽  
Alberto Oddo ◽  
Anders Løbner-Olesen ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Pseudomonas Aeruginosa ◽  
Health Concern ◽  
Side Chain ◽  
Resistant Bacteria ◽  
Bacterial Strains ◽  
Major Health ◽  
E Coli ◽  
Drug Resistant Bacteria ◽  
Multicellular Organisms

The emergence of multi-drug resistant bacteria is becoming a major health concern. New strategies to combat especially Gram-negative pathogens are urgently needed. Antimicrobial peptides (AMPs) found in all multicellular organisms act as a first line of defense in immunity. In recent years, AMPs have attracted increasing attention as potential antibiotics. Naturally occurring antimicrobial cyclic lipopeptides include colistin and daptomycin, both of which contain a flexible linker. We previously reported a cyclic AMP BSI-9 cyclo(Lys-Nal-Lys-Lys-Bip-O2Oc-Nal-Lys-Asn) containing a flexible linker, with a broad spectrum of activity against bacterial strains and low hemolytic activity. In this study, improvement of the antimicrobial activity of BSI-9, against the European Committee on Antimicrobial Susceptibility Testing (EUCAST) strains of S. aureus, E. coli, A. baumannii, and P. aeruginosa was examined. This led to synthesis of eighteen peptide analogues of BSI-9, produced in four individual stages, with a different focus in each stage; cyclization point, hydrophobicity, cationic side-chain length, and combinations of the last two. Specifically the modified compound 11, exhibited improved activity against Staphylococcus aureus and Pseudomonas aeruginosa with MIC of 4 µg/mL and 8 µg/mL, respectively, compared to the original BSI-9, which had an MIC of 16–32 µg/mL.

scholarly journals Novel Seleno- and Thio-Urea Containing Dihydropyrrol-2-One Analogues as Antibacterial Agents

Antibiotics ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 321
Author(s):  
Shekh Sabir ◽  
Tsz Tin Yu ◽  
Rajesh Kuppusamy ◽  
Basmah Almohaywi ◽  
George Iskander ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Antibiotic Resistance ◽  
Quorum Sensing ◽  
Antibacterial Agents ◽  
Inhibitory Concentration ◽  
Resistant Bacteria ◽  
Drug Resistant ◽  
Positive Bacterium ◽  
Quorum Sensing Inhibition ◽  
Drug Resistant Bacteria

The quorum sensing (QS) system in multi-drug-resistant bacteria such as P. aeruginosa is primarily responsible for the development of antibiotic resistance and is considered an attractive target for antimicrobial drug discovery. In this study, we synthesised a series of novel selenourea and thiourea-containing dihydropyrrol-2-one (DHP) analogues as LasR antagonists. The selenium DHP derivatives displayed significantly better quorum-sensing inhibition (QSI) activities than the corresponding sulphur analogues. The most potent analogue 3e efficiently inhibited the las QS system by 81% at 125 µM and 53% at 31 µM. Additionally, all the compounds were screened for their minimum inhibitory concentration (MIC) against the Gram-positive bacterium S. aureus, and interestingly, only the selenium analogues showed antibacterial activity, with 3c and 3e being the most potent with a MIC of 15.6 µM.

scholarly journals Resistance and Adaptation of Bacteria to Non-Antibiotic Antibacterial Agents: Physical Stressors, Nanoparticles, and Bacteriophages

Antibiotics ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 435
Author(s):  
Sada Raza ◽  
Kinga Matuła ◽  
Sylwia Karoń ◽  
Jan Paczesny
Keyword(s):  
Antimicrobial Resistance ◽  
Antibacterial Agents ◽  
Uv Light ◽  
Resistance Mechanisms ◽  
Resistant Bacteria ◽  
Physical Factors ◽  
Defense Systems ◽  
Drug Resistant Bacteria

Antimicrobial resistance is a significant threat to human health worldwide, forcing scientists to explore non-traditional antibacterial agents to support rapid interventions and combat the emergence and spread of drug resistant bacteria. Many new antibiotic-free approaches are being developed while the old ones are being revised, resulting in creating unique solutions that arise at the interface of physics, nanotechnology, and microbiology. Specifically, physical factors (e.g., pressure, temperature, UV light) are increasingly used for industrial sterilization. Nanoparticles (unmodified or in combination with toxic compounds) are also applied to circumvent in vivo drug resistance mechanisms in bacteria. Recently, bacteriophage-based treatments are also gaining momentum due to their high bactericidal activity and specificity. Although the number of novel approaches for tackling the antimicrobial resistance crisis is snowballing, it is still unclear if any proposed solutions would provide a long-term remedy. This review aims to provide a detailed overview of how bacteria acquire resistance against these non-antibiotic factors. We also discuss innate bacterial defense systems and how bacteriophages have evolved to tackle them.

scholarly journals Agreement Assessment of Tigecycline Susceptibilities Determined by the Disk Diffusion and Broth Microdilution Methods among Commonly Encountered Resistant Bacterial Isolates: Results from the TigecyclineIn VitroSurveillance in Taiwan (TIST) Study, 2008 to 2010

2011 ◽  
Vol 56 (3) ◽  
pp. 1414-1417 ◽  
Author(s):  
Jien-Wei Liu ◽  
Wen-Chien Ko ◽  
Cheng-Hua Huang ◽  
Chun-Hsing Liao ◽  
Chin-Te Lu ◽  
...  
Keyword(s):  
Susceptibility Testing ◽  
Total Error ◽  
Error Rates ◽  
Resistant Bacteria ◽  
Drug Resistant ◽  
Broth Microdilution ◽  
Content Type ◽  
E Coli ◽  
Drug Resistant Bacteria

ABSTRACTThe TigecyclineIn VitroSurveillance in Taiwan (TIST) study, initiated in 2006, is a nationwide surveillance program designed to longitudinally monitor thein vitroactivity of tigecycline against commonly encountered drug-resistant bacteria. This study compared thein vitroactivity of tigecycline against 3,014 isolates of clinically important drug-resistant bacteria using the standard broth microdilution and disk diffusion methods. Species studied included methicillin-resistantStaphylococcus aureus(MRSA;n= 759), vancomycin-resistantEnterococcus faecium(VRE;n= 191), extended-spectrum β-lactamase (ESBL)-producingEscherichia coli(n= 602), ESBL-producingKlebsiella pneumoniae(n= 736), andAcinetobacter baumannii(n= 726) that had been collected from patients treated between 2008 and 2010 at 20 hospitals in Taiwan. MICs and inhibition zone diameters were interpreted according to the currently recommended U.S. Food and Drug Administration (FDA) criteria and the European Committee on Antimicrobial Susceptibility Testing (EUCAST) criteria. The MIC90values of tigecycline against MRSA, VRE, ESBL-producingE. coli, ESBL-producingK. pneumoniae, andA. baumanniiwere 0.5, 0.125, 0.5, 2, and 8 μg/ml, respectively. The total error rates between the two methods using the FDA criteria were high: 38.4% for ESBL-producingK. pneumoniaeand 33.8% forA. baumannii. Using the EUCAST criteria, the total error rate was also high (54.6%) forA. baumanniiisolates. The total error rates between these two methods were <5% for MRSA, VRE, and ESBL-producingE. coli. For routine susceptibility testing of ESBL-producingK. pneumoniaeandA. baumanniiagainst tigecycline, the broth microdilution method should be used because of the poor correlation of results between these two methods.

Nghiên cứu sự kháng kháng sinh của các chủng vi khuẩn gây nhiễm khuẩn đường tiết niệu phân lập được tại Bệnh viện Hữu nghị Đa khoa Nghệ An

2021 ◽  
Author(s):  
Trâm Quế Anh
Keyword(s):  
Urinary Tract ◽  
General Hospital ◽  
Urinary Tract Infections ◽  
Resistant Bacteria ◽  
Antibiotics Resistance ◽  
Bacterial Strains ◽  
E Coli ◽  
Linezolid Resistance ◽  
Drug Resistant Bacteria ◽  
Tract Infections

TÓM TẮT Đặt vấn đề: Xác định đúng căn nguyên gây NKĐTN và mức độ kháng kháng sinh của các vi khuẩn sẽ giúp cho việc điều trị có hiệu quả, giảm được chi phí điều trị, hạn chế sự gia tăng vi khuẩn đề kháng kháng sinh. Đối tượng và phương pháp nghiên cứu: Các chủng VK gây nhiễm khuẩn đương tiết niệu phân lập được tại bệnh viện Hữu nghị Đa khoa Nghệ An từ 1/2020 đến 12/2020. Thiết kế nghiên cứu: Cắt ngang mô tả. Kết quả: Phân lập được 473 chủng vi khuẩn gây NKĐTN, trong đó, E. coli 38,48%; P. aeruginosa 14,15; Enterococcus sp 10,57; K. pneumoniae 13,32%. E. coli: kháng các kháng sinh Cephalosporine, Quinolones từ 56,7 - 63,8%, Carbapenem 4,5 - 6,2%, sinh ESBL 49,4%. P. aeruginosa: đã kháng các kháng sinh thử nghiệm từ 59,1 - 69,2%. Enterococcus sp: kháng với các kháng sinh nhóm Quinolone 73,5%, kháng Vancomycin 8,3%; Chưa ghi nhận đề kháng Linezolid. K. pneumoniae: kháng nhóm Cephalosporin, Quinolone từ 66,7 - 74,6%, đề kháng với Carbapenem từ 46,0 - 50,8%. Kết luận: Các vi khuẩn gây nhiễm khuẩn tiết niệu thường gặp là: E. coli, P. aeruginosa, Enterococcus sp. K. pneumoniae. Các vi khuẩn phân lập được đã đề kháng với nhiều kháng sinh thường dùng với các mức độ khác nhau. Xuất hiện các chủng vi khuẩn Gram âm kháng Carbapenem, Gram dương kháng Vancomycin. Từ khóa: Nhiễm khuẩn tiết niệu, E.coli, Klebsiella, P.aeruginosa, Enterococcus sp ABSTRACT RESEARCH OF ANTIBIOTICS RESISTANCE OF BACTERIA STRAINS CAUSING URINARY TRACT INFECTIONS ISOLATED AT NGHEAN FRIENDSHIP GENERAL HOSPITAL Background: The good identification of UTI microorganism and their antimicrobial susceptibility would promote the effective treatment, reduce the cost as well as the emergence of drug resistant bacteria. Methods: Bacterial strains causing urinary tract infections were isolated at Nghe An Friendship General Hospital from 1/2020 to 12/2020. Study design: Descriptive cross section. Results: 473 bacterial strains causing UTIs were isolated, in which, E. coli 38.48%; P. aeruginosa 14.15; Enterococcus sp 10.57; K. pneumoniae 13.32%. E. coli: resistant to Cephalosporin antibiotics, Quinolones from 56.7 - 63.8%, Carbapenem 4.5 - 6.2%, producing ESBL 49.4%. P. aeruginosa: was resistant to the tested antibiotics from 59.1 - 69.2%. Enterococcus sp: resistant to Quinolone antibiotics 73.5%, resistant to Vancomycin 8.3%; Linezolid resistance has not been recorded. K. pneumoniae: resistant to Cephalosporin, Quinolone from 66.7 - 74.6%, resistant to Carbapenem from 46.0 - 50.8%. Conclusion: Common bacteria causing urinary tract infections are: E. coli, P. aeruginosa, Enterococcus sp. K. pneumoniae. The isolates were resistant to many commonly used antibiotics to varying degrees. Occurrence of strains of Gram - negative bacteria resistant to Carbapenem, Gram - positive resistant to Vancomycin. Keywords: Urinary Tract infections, E. coli, Klebsiella, P. aeruginosa, Enterococcus sp.

scholarly journals Antibiotic Resistance of Escherichia Coli Isolated from Lake Nainital, Uttarakhand State, India

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Neha Giri ◽  
Anchal Lodhi ◽  
Devendra Singh Bisht ◽  
Suvarna Bhoj ◽  
Deepak Kumar Arya
Keyword(s):  
Escherichia Coli ◽  
Antibiotic Resistance ◽  
Multiple Drug Resistance ◽  
Health Concern ◽  
Penicillin G ◽  
Resistant Bacteria ◽  
Sample Collection ◽  
E Coli ◽  
Mar Index ◽  
Collection Sites

Researchers have encountered new challenges with the discovery of multiple drug resistance in microbes. Currently, multidrug resistant bacteria are considered a major public health concern and an emerging global epidemic. Presence of Escherichia coli in water is used as a faecal pollution measure. In this study E. coli isolates were collected from 20 sample collection sites at Lake Nainital. 20 E. coli isolates, 1 from each sample collection sites, were examined for their antibiotic response patterns against a panel of widely used 15 antibiotics. The result of this study showed 100% resistance to Penicillin G followed by Erythromycin (80%). All isolates (100%) were found susceptible for Gentamycin. The susceptibilities for Chloramphenicol and Co-trimoxazaole were found next to Gentamycin as 90 and 85% respectively. Multiple antibiotic resistance (MAR) index was also determined. 0.73 MAR index was observed as highest in 1 isolate. 13 out of 20 isolates had more than 0.2 MAR indices. The result reveals the origin of E. coli isolates from an area of high antibiotics use.

An unexpected discovery toward novel membrane active sulfonyl thiazoles as potential MRSA DNA intercalators

2020 ◽  
Vol 12 (19) ◽  
pp. 1709-1727 ◽  
Author(s):  
Yuan-Yuan Hu ◽  
Juan Wang ◽  
Tie-Jun Li ◽  
Rammohan R Yadav Bheemanaboina ◽  
Mohammad Fawad Ansari ◽  
...  
Keyword(s):  
Mammalian Cells ◽  
Antibacterial Agents ◽  
Antimicrobial Agents ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Inhibitory Concentration ◽  
Resistant Bacteria ◽  
Drug Resistant ◽  
Dna Intercalators ◽  
Dna Targeting ◽  
Drug Resistant Bacteria

Aim: With the increasing emergence of drug-resistant bacteria, the need for new antimicrobial agents has become extremely urgent. This work was to develop sulfonyl thiazoles as potential antibacterial agents. Results & methodology: Novel hybrids of sulfonyl thiazoles were developed from commercial acetanilide and acetylthiazole. Hybrids 6e and 6f displayed excellent inhibitory efficacy against clinical methicillin-resistant Staphylococcus aureus (MRSA) (minimum inhibitory concentration = 1 μg/ml) without obvious toxicity toward normal mammalian cells (RAW 264.7). The combination uses were found to improve the antimicrobial ability. Further preliminary antibacterial mechanism experiments showed that the active molecule 6f could effectively interfere with MRSA membrane and insert into MRSA DNA. Conclusion: Compounds 6e and 6f could serve as potential DNA-targeting templates toward the development of promising antimicrobial agents.

scholarly journals Antibiotic Resistance Patterns of Diverse Escherichia coli Phylogenetic Groups Isolated from the Al-Hillah River in Babylon Province, Iraq

2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Mourouge Saadi Alwash ◽  
Hawraa Mohammed Al-Rafyai
Keyword(s):  
Escherichia Coli ◽  
Antibiotic Resistance ◽  
Anthropogenic Activities ◽  
Health Concern ◽  
Resistant Bacteria ◽  
Anthropogenic Pressures ◽  
Phylogenetic Groups ◽  
E Coli ◽  
Resistance Patterns ◽  
Antibiotic Resistance Patterns

Surface water contamination remains a major worldwide public health concern and may contribute to the dissemination of antibiotic-resistant bacteria. The Al-Hillah River in the city of Babylon Province, Iraq, diverts flows from the Euphrates River. Because of its importance in irrigation and population density, it faces several forced and unforced changes due to anthropogenic activities. To evaluate water quality, water samples were collected from three sites with different anthropogenic pressures along the Al-Hillah River. These samples were subjected to bacteriological analyses, i.e., total coliforms, Escherichia coli, and faecal enterococci. The phylogenetic groups of the E. coli isolates (n = 61) were typed by rapid PCR-based analyses. Representatives of each isolate were tested phenotypically for resistance to six classes of antibiotics and characterized according to their phylogenetic groups. The results demonstrated the highest resistance levels were to β-lactam antibiotics, followed by fosfomycin and aminoglycosides. Escherichia coli isolates belonging to phylogenetic groups A and B2 were the most common and were characterized by a higher prevalence of antibiotic resistance. This study is important for understanding the current conditions of the Al-Hillah River, as the data reveal a high prevalence of multiresistance among E. coli isolates circulating at the three sampling sites.

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