Antibiotic resistance continues to plague antimicrobial chemotherapy of infectious disease. And while true biocide resistance is as yet unrealized, in vitro and in vivo episodes of reduced biocide susceptibility are common and the history of antibiotic resistance should not be ignored in the development and use of biocidal agents. Efflux mechanisms of resistance, both drug specific and multidrug, are important determinants of intrinsic and/or acquired resistance to these antimicrobials, with some accommodating both antibiotics and biocides. This latter raises the spectre (as yet generally unrealized) of biocide selection of multiple antibiotic-resistant organisms. Multidrug efflux mechanisms are broadly conserved in bacteria, are almost invariably chromosome-encoded and their expression in many instances results from mutations in regulatory genes. In contrast, drug-specific efflux mechanisms are generally encoded by plasmids and/or other mobile genetic elements (transposons, integrons) that carry additional resistance genes, and so their ready acquisition is compounded by their association with multidrug resistance. While there is some support for the latter efflux systems arising from efflux determinants of self-protection in antibiotic-producing Streptomyces spp. and, thus, intended as drug exporters, increasingly, chromosomal multidrug efflux determinants, at least in Gram-negative bacteria, appear not to be intended as drug exporters but as exporters with, perhaps, a variety of other roles in bacterial cells. Still, given the clinical significance of multidrug (and drug-specific) exporters, efflux must be considered in formulating strategies/approaches to treating drug-resistant infections, both in the development of new agents, for example, less impacted by efflux and in targeting efflux directly with efflux inhibitors.

/pdf/efflux-mediated-antimicrobial-resistance-2rhfe93zak.pdf

Efflux-mediated antimicrobial resistance

Antimicrobial compounds having formula (II), (III), (IV), (IV-A) or (V) as well as pharmaceutically acceptable salts, esters or prodrugs thereof; pharmaceutical compositions comprising such compounds; methods of treating bacterial infections by the administration of such compounds; and processes for the preparation of the compunds.

6-o-substituted ketolides having antibacterial activity

Magnesium-methanol as a simple convenient reducing agent for α,β -unsaturated esters

For clarification of the nature of the side effects of macrolide antibiotics on the gastrointestinal tract, the motor-stimulating activity of these agents was studied in unanesthetized dogs. The results showed that erythromycin and oleandomycin, the 14-membered macrolides with two side chain sugars combined at C3 and C5 in a glycosidic linkage in parallel, strongly stimulate gastrointestinal motor activity, an action accompanied by vomiting at large doses. On the other hand, leucomycin, acetylspiramycin, and tylosin, belonging to a 16-membered macrolide with two side chain sugars in series combined at C5 of the lactone ring, did not induce contractions of the gastrointestinal tract. Motor-stimulating activity by erythromycin and oleandomycin was greatly inhibited by atropine sulfate. These results point to structure-physiological activity relationships.

Gastrointestinal motorstimulating activity of macrolide antibiotics and analysis of their side effects on the canine gut

A 6-O-methylerythromycin A derivative represented by general formula (I) and pharmaceutically acceptable salts thereof, having a potent antibacterial activity against gram-negative bacteria and a more potent activity against gram-positive bacteria than that of known compounds. In the said formula, R?1 and R2? represent each hydrogen or C?1? to C3 alkyl, and A represents nitrogen or N←O.

6-o-methylerythromycin a derivative

Catalytic Transfer Hydrogenation of Indoles to Indolines in Formic Acid

Erythromycins showing an extremely relieved bitterness at administration and an improved absorbability in vivo when orally administered are provided. A compound having a group represented by the following formula: --O--CO--O--[(CH.sub.2).sub.m --O].sub.n --R (wherein R represents an alkyl group having from 1 to 12 carbon atoms, m represents an integer of from 2 to 4, and n represents an integer of from 1 to 7) at the 2'-position of erythromycins or a salt thereof.

2'-position modified compound of erythromycin or its derivative

An erythromycin A derivative represented by formula (I), wherein n is an integer of 1 to 7, R1 is a hydrogen atom or an alkyl group, R2 is a quinolyl group, a pyrazinyl group, a benzimidazolyl group, a thiazolyl group, a pyridyl group, a pyrimidyl group, a purinyl group, a triazinyl group, a phenyl group or a naphthyl group, R3 is a hydrogen atom, an alkyl group or a cinnamyl group, R4 is a hydrogen atom, or R?4 and R5? together form an oxo group, R5 is a group represented by the formula: -OCO-CH?2-R?8, -OCO-R8, -OCO-NH-R?8, -O-R8? or -OCO-O-R?8; and R6 and R7? are each a hydrogen atom or an alkyl group, or a pharmaceutically acceptable salt thereof has a strong antibacterial activity against not only erythromycin-sensitive bacteria but also erythromycin-resistant bacteria.

Erythromycin a 11, 12-carbamate derivatives

In order to develop new-generation macrolide antibiotics active against erythromycin (EM)-resistant strains, a series of 6-O-methyl EM 9-O-substituted oxime derivatives was synthesized and evaluated for antibacterial activity against EM-resistant (S. aureus J-109) and susceptible (S. aureus 209P) strains. To understand how substituents affect the biological activity, the quantitative structure-activity relationships (QSAR) was analyzed using the Hansch-Fujita method. With the EM-resistant strain, the positive coefficient for log P may indicate that higher hydrophobicity of molecules is favorable for antibacterial activity. The negative coefficients of the Sterimol parameters L, B1, and B5 may indicate that long, bulky substituents are unfavorable. With the EM-susceptible strain, the negative coefficient for log P may indicate that hydrophilicity is important for antibacterial activity. A short substituent is also required to improve the activity. Based on the QSAR model, a derivative (87) having an anthracenylmethyl moiety was synthesized to reinforce and confirm the correlation. The activity of 87 against the EM-resistant strain was significant. In QSARs of 6-O-methyl EM-A 9-O-substituted oxime derivatives, the difference of the contribution of log P to the antibacterial activity between EM-resistant and susceptible strains was clearly recognized.

Structure-activity relationship study of 6-O-Methylerythromycin 9-O-substituted oxime derivatives

In vitro and in vivo Antibacterial Activities of the Tricyclic Ketolide TE‐802 and Its Analogues.

Handle everyday research tasks with reliable, citation-backed results

Your personal Research Agent to handle research tasks with citation-backed results

Popular Tasks used by Researchers

How can I help with your research?

Meet SciSpace

Get more enhanced response by uploading the PDFs you want me to reference.

No relevant PDFs in your library

SciSpace is the AI research assistant for academics. Run systematic literature reviews on 280M+ papers, and write papers with cited sources. Trusted by 1M+ students, PhDs & researchers.

SciSpace | AI for Research

Analyze PDFs

Code & Manuscripts

Funding & Grants

Literature & Patents

Medical & Clinical Data

Systematic Review

Visualize & Present

Web & Data

Build a Google Scholar-like website for your research.

Build a website

Create charts and images for your research

Create a Chart

Write a paper for submission to a journal

Draft a manuscript

Patent Search

Design eye-catching scientific posters in minutes.

Scientific Poster Generation

Systematic Literature Review

One task is running at the moment. Your messages will be shown right after.

Drag and drop or click here to browse

Loved by <highlight>1 million+</highlight> researchers

Extract a list of specific topics and their sources from unstructured text

Topics

Compare and analyze relevant papers that matches with your search

Papers

Get insights from PDFs and bookmarked papers from your library

My library

Recent searches

Try searching for:

Catch AI-generated content in scholarly and non-scholarly content

{ai} Detector

Ai Writer

Get PDF Summaries, highlighted text explanations 

Chat with PDF

Effortlessly create in-text citations and bibliographies in APA and 2,500 other formats

Citation generator

Get explanations, summaries, and answers on academic papers

Ease up your research workflow with {scispace}'s cohort of exciting AI tools

Elevate your academic writing skills and convey your ideas the way you want

Paraphraser

Explore our range of reading and writing tools

Your file is being prepared and should be ready in a few minutes. If it's a large file, it might take a bit longer. You can close this window, and we'll email you the file when it's done.

You have reached a maximum limit of <strong>{limit}</strong> columns in the table. Remove at least <strong>1</strong> column to add or create another one.

Masato Kashimura

Author Tools

Chat about Author