scholarly journals Synergistic Effect of Glycyrrhizic Acid and ZnO/Palygorskite on Improving Chitosan-Based Films and Their Potential Application in Wound Healing

Polymers ◽  
2021 ◽  
Vol 13 (22) ◽  
pp. 3878
Author(s):  
Qian Zhang ◽  
Hong Zhang ◽  
Aiping Hui ◽  
Junjie Ding ◽  
Xinyue Liu ◽  
...  
Keyword(s):  
Synergistic Effect ◽  
Glycyrrhizic Acid ◽  
Wound Care ◽  
Antibacterial Properties ◽  
Nanocomposite Films ◽  
Resistant Bacteria ◽  
Promising Candidate ◽  
E Coli ◽  
Drug Resistant Bacteria ◽  
Solution Casting Method

The synergistic effect of chitosan (CS), glycyrrhizic acid (GA) and ZnO/palygorskite (ZnO/PAL) as potential wound dressing was evaluated in the form of films by the solution casting method. The nanocomposite films were well-characterized with ATR-FTIR, XRD and SEM to explore the interactions between CS, GA and ZnO/PAL. Physical, mechanical and antibacterial properties of the nanocomposite films were systematically investigated for their reliability in end-up utilization. Importantly, it was found that the presence of PAL in the films provided enhanced mechanical properties, whereas CS, GA and ZnO supplied a broad-spectrum antibacterial activity, especially for drug-resistant bacteria such as ESBL—E. coli and MRSA. Overall, this research demonstrated that the prepared films can be a promising candidate for wound-care materials.

scholarly journals Investigation of Functionalized Surface Charges of Thermoplastic Starch/Zinc Oxide Nanocomposite Films Using Polyaniline: The Potential of Improved Antibacterial Properties

Polymers ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 425
Author(s):  
Korakot Charoensri ◽  
Chatchai Rodwihok ◽  
Duangmanee Wongratanaphisan ◽  
Jung A. Ko ◽  
Jin Suk Chung ◽  
...  
Keyword(s):  
Zinc Oxide ◽  
Antibacterial Activity ◽  
Antibacterial Properties ◽  
Thermoplastic Starch ◽  
Nanocomposite Films ◽  
Resistant Bacteria ◽  
Surface Charges ◽  
Zno Nps ◽  
E Coli ◽  
Bionanocomposite Films

Improving the antibacterial activity of biodegradable materials is crucial for combatting widespread drug-resistant bacteria and plastic pollutants. In this work, we studied polyaniline (PANI)-functionalized zinc oxide nanoparticles (ZnO NPs) to improve surface charges. A PANI-functionalized ZnO NP surface was prepared using a simple impregnation technique. The PANI functionalization of ZnO successfully increased the positive surface charge of the ZnO NPs. In addition, PANI-functionalized ZnO improved mechanical properties and thermal stability. Besides those properties, the water permeability of the bionanocomposite films was decreased due to their increased hydrophobicity. PANI-functionalized ZnO NPs were applied to thermoplastic starch (TPS) films for physical properties and antibacterial studies using Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). The PANI-functionalized ZnO bionanocomposite films exhibited excellent antibacterial activity for both E. coli (76%) and S. aureus (72%). This result suggests that PANI-functionalized ZnO NPs can improve the antibacterial activity of TPS-based bionanocomposite films.

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 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 Synthesis, Structure Elucidation, Antibacterial Activities, and Synergistic Effects of Novel Juglone and Naphthazarin Derivatives Against Clinical Methicillin-Resistant Staphylococcus aureus Strains

2021 ◽  
Vol 9 ◽  
Author(s):  
Valentin Duvauchelle ◽  
Chaimae Majdi ◽  
David Bénimélis ◽  
Catherine Dunyach-Remy ◽  
Patrick Meffre ◽  
...  
Keyword(s):  
Synergistic Effects ◽  
Antibacterial Properties ◽  
Clinical Importance ◽  
Antibacterial Activities ◽  
Multidrug Resistant ◽  
Resistant Bacteria ◽  
Global Public Health ◽  
Gram Positive ◽  
Drug Resistant Bacteria ◽  
Mrsa Strains

Infections caused by drug-resistant bacteria are a serious threat to human and global public health. Moreover, in recent years, very few antibiotics have been discovered and developed by pharmaceutical companies. Therefore, there is an urgent need to discover and develop new antibacterial agents to combat multidrug-resistant bacteria. In this study, two novel series of juglone/naphthazarin derivatives (43 compounds) were synthesized and evaluated for their antibacterial properties against various clinical and reference Gram-positive MSSA, clinical Gram-positive MRSA, and clinical and reference Gram-negative bacteria E. coli and P. aeruginosa. These strains are of clinical importance because they belong to ESKAPE pathogens. Compounds 3al, 5ag, and 3bg showed promising activity against clinical and reference MSSA (MIC: 1–8 µg/ml) and good efficacy against clinical MRSA (MIC: 2–8 µg/ml) strains. 5am and 3bm demonstrated better activity on both MSSA (MIC: 0.5 µg/ml) and MRSA (MIC: 2 µg/ml) strains. Their MICs were similar to those of cloxacillin against clinical MRSA strains. The synergistic effects of active compounds 3al, 5ag, 5am, 3bg, and 3bm were evaluated with reference antibiotics, and it was found that the antibiotic combination with 3bm efficiently enhanced the antimicrobial activity. Compound 3bm was found to restore the sensitivity of clinical MRSA to cloxacillin and enhanced the antibacterial activity of vancomycin when they were added together. In the presence of 3bm, the MIC values of vancomycin and cloxacillin were lowered up to 1/16th of the original MIC with an FIC index of 0.313. Moreover, compounds 3al, 5ag, 5am, 3bg, and 3bm did not present hemolytic activity on sheep red blood cells. In silico prediction of ADME profile parameter results for 3bm is promising and encouraging for further development.

scholarly journals Trends in the Susceptibility of Clinically Important Resistant Bacteria to Tigecycline: Results from the TigecyclineIn VitroSurveillance in Taiwan Study, 2006 to 2010

2011 ◽  
Vol 56 (3) ◽  
pp. 1452-1457 ◽  
Author(s):  
Yen-Hsu Chen ◽  
Po-Liang Lu ◽  
Cheng-Hua Huang ◽  
Chun-Hsing Liao ◽  
Chin-Te Lu ◽  
...  
Keyword(s):  
Resistant Bacteria ◽  
Gram Negative Bacteria ◽  
Drug Resistant ◽  
Content Type ◽  
E Coli ◽  
Drug Resistant Bacteria ◽  
Vancomycin Resistant ◽  
Susceptibility Rate ◽  
Important Drug

ABSTRACTThe TigecyclineIn VitroSurveillance in Taiwan (TIST) study, a nationwide, prospective surveillance during 2006 to 2010, collected a total of 7,793 clinical isolates, including methicillin-resistantStaphylococcus aureus(MRSA) (n= 1,834), penicillin-resistantStreptococcus pneumoniae(PRSP) (n= 423), vancomycin-resistant enterococci (VRE) (n= 219), extended-spectrum β-lactamase (ESBL)-producingEscherichia coli(n= 1,141), ESBL-producingKlebsiella pneumoniae(n= 1,330),Acinetobacter baumannii(n= 1,645), andStenotrophomonas maltophilia(n= 903), from different specimens from 20 different hospitals in Taiwan. MICs of tigecycline were determined following the criteria of the U.S. Food and Drug Administration (FDA) and the European Committee on Antimicrobial Susceptibility Testing (EUCAST-2011). Among drug-resistant Gram-positive pathogens, all of the PRSP isolates were susceptible to tigecycline (MIC90, 0.03 μg/ml), and only one MRSA isolate (MIC90, 0.5 μg/ml) and three VRE isolates (MIC90, 0.125 μg/ml) were nonsusceptible to tigecycline. Among the Gram-negative bacteria, the tigecycline susceptibility rates were 99.65% for ESBL-producingE. coli(MIC90, 0.5 μg/ml) and 96.32% for ESBL-producingK. pneumoniae(MIC90, 2 μg/ml) when interpreted by FDA criteria but were 98.7% and 85.8%, respectively, when interpreted by EUCAST-2011 criteria. The susceptibility rate forA. baumannii(MIC90, 4 μg/ml) decreased from 80.9% in 2006 to 55.3% in 2009 but increased to 73.4% in 2010. A bimodal MIC distribution was found among carbapenem-susceptibleA. baumanniiisolates, and a unimodal MIC distribution was found among carbapenem-nonsusceptibleA. baumanniiisolates. In Taiwan, tigecycline continues to have excellentin vitroactivity against several major clinically important drug-resistant bacteria, with the exception ofA. baumannii.

scholarly journals The effective photocatalysis and antibacterial properties of AgBr/AgVO3 composites under visible-light

RSC Advances ◽  
2019 ◽  
Vol 9 (63) ◽  
pp. 37109-37118 ◽  
Author(s):  
Jie Zhang ◽  
Jia Wang ◽  
Huihui Xu ◽  
Xianzi Lv ◽  
YuXiang Zeng ◽  
...  
Keyword(s):  
Visible Light ◽  
Human Health ◽  
Organic Pollutants ◽  
Water Cycle ◽  
Water Environment ◽  
Antibacterial Properties ◽  
Resistant Bacteria ◽  
Drug Resistant ◽  
Drug Resistant Bacteria

With the discharge of large amount of organic pollutants and antibiotics into the water environment, the water cycle has been seriously polluted, and at the same time, various drug-resistant bacteria have emerged in succession, which poses a serious threat to human health.

scholarly journals Rectal Colonization by Drug Resistant Bacteria in Nursing Home Residents in Crete, Greece

2021 ◽  
Vol 6 (3) ◽  
pp. 123
Author(s):  
Aikaterini Moschou ◽  
Petros Ioannou ◽  
Eleni Moraitaki ◽  
Dimitra Stafylaki ◽  
Sofia Maraki ◽  
...  
Keyword(s):  
Nursing Home ◽  
Nursing Home Residents ◽  
Resistant Bacteria ◽  
Antimicrobial Use ◽  
Drug Resistant ◽  
Extended Spectrum Beta Lactamase ◽  
E Coli ◽  
Drug Resistant Bacteria ◽  
High Prevalence ◽  
Rectal Colonization

(1) Background: In an area with a high prevalence of multi-drug resistant Gram-negative bacteria (MDR-GNB), we investigated the colonization of nursing home residents by such organisms. (2) Methods: A point prevalence study was performed in six nursing homes of the Heraklion area on the island of Crete. A rectal swab was taken and cultured from each participant, while additional risk factors such as recent hospitalization or antimicrobial usage were recorded and evaluated. (3) Results: A total of 137 nursing home residents were included in the study. Their mean age was 82.1 years and 19.7% were males. In total, cultures yielded 255 GNB; E. coli, K. pneumoniae and P. aeruginosa were the most common. Among the microorganisms cultured, 17.6% had the extended-spectrum beta-lactamase phenotype, while 18% were MDR. A statistically significant association was found between recent antimicrobial use and colonization by MDR-GNB; (4) Conclusions: Colonization by MDR-GNB was found to be highly prevalent in nursing home residents. Recent antimicrobial use was associated with MDR-GNB carriage.

scholarly journals Identification of antibiotic-producing Bacillus sensu lato isolated from national parks of Hoang Lien and Phu Quoc in Vietnam

2014 ◽  
Vol 6 (1) ◽  
pp. 77-83
Author(s):  
Thi Tuyet Van Dinh ◽  
Nguyen Hai Linh Bui ◽  
Van Hop Duong ◽  
Mai Phuong Doan ◽  
Thanh Trung Trinh
Keyword(s):  
National Parks ◽  
Broad Spectrum ◽  
Antibiotic Production ◽  
Antagonistic Activity ◽  
Bacillus Species ◽  
Resistant Bacteria ◽  
Viet Nam ◽  
Drug Resistant ◽  
E Coli ◽  
Drug Resistant Bacteria

Many lipopeptide antibiotics produced from Bacillus sensu lato (Bacillus s. l.) against drug-resistant bacteria have been recently reported. To explore the potential production of the antibiotics from this group of bacteria in Vietnam, we collected 38 soil samples from two national parks of Hoang Lien and Phu Quoc and isolated 411Bacillus s. l. strains. Of those, 22 strains had antagonistic activity against both susceptible S. aureus and E. coli. The strains were further tested on drug-resistant bacteria collected at Bach Mai hospital and 20 strains demonstrated antagonistic activity against at least 2 of 18 drug-resistant bacteria K. pneumoniae, E. coli, A. baumannii and S. aureus. Analysis of 16S rDNA sequence showed that most of the broad spectrum antibiotic producers were Paenibacillus species whereas narrow spectrum antibiotic producers were Bacillus species. Strains PQH 0103 and PQH 0410 were probably produced novel antibiotic agents as they suspected to be novel taxa in Paenibacillus genus. Moreover, strains PQH 1509 and PQH 1702 produced broad spectrum antibiotics were identified as P. chitinolyticus. To our best knowledge, there is no report on antibiotic production from this species. Further elucidation of chemical structure of antibiotics produced from Bacillus s. l. isolated in soils of Vietnam is needed. Gần đây, nhiều kháng sinh lipopeptide từ vi khuẩn Bacillus sensu lato (Bacillus s. l.) có khả năng sinh kháng sinh kháng vi khuẩn kháng thuốc đã được phát hiện và công bố. Để tìm hiểu khả năng sinh kháng sinh của nhóm vi khuẩn này ở Việt Nam, chúng tôi tiến hành thu thập 38 mẫu đất tại vườn Quốc gia Hoàng Liên và vườn Quốc gia Phú Quốc và phân lập được 411 chủng vi khuẩn Bacillus s. l.. Trong số đó, 22 chủng có khả năng sinh kháng sinh kháng 2 chủng vi khuẩn S. aureus và E. coli nhậy cảm thuốc. 20 trong số 22 chủng này có hoạt tính kháng ít nhất từ 2 đến 18 chủng kiểm định kháng thuốc thuộc các loài K. pneumoniae, E. coli, A. baumannii và S. aureus. Dựa trên kết quả phân loại bằng trình tự gene 16S rRNA, các chủng Bacillus s. l. sinh kháng sinh phổ rộng là các loài Paenibacillus trong khi đó các loài sinh kháng sinh phổ hẹp là Bacillus. Trên cây phát sinh chủng loại, chủng PQH 0103 và PQH 0410 có thể là những loài mới và có tiềm năng sinh các chất kháng sinh mới. Hơn nữa, chủng PQH 1509 và PQH 1702 sinh kháng sinh phổ rộng được phân loại vào loài P. chitinolyticus. Đây là loài chưa có công bố nào về khả năng sinh chất kháng sinh và có thể là loài sinh chất kháng sinh mới. Nghiên cứu giải mã cấu trúc chất kháng sinh từ các loài Bacillus s. l. phân lập tại Việt Nam cần được làm rõ trong tương lai.

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