Notes in 08AntibacterialMOAs&BacterialResistanceMechanisms

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Published	07/30/2024	{{c1::Quinolones}} target {{c2::DNA gyrase}} in {{c2::gram-negative}} bacteria and {{c3::topoisomerase IV}} in {{c3::gram-pos…
Published	07/30/2024	{{c1::DNA gyrase inhibitors (flouroquinolones}} are synthetic fluorinated analogs of {{c2::nalidixic acid}}.
Published	07/30/2024	{{c1::T::T/F}} DNA gyrase inhibitors (flouroquinolones) are active against both gram-positive and negative bacteria.
Published	07/30/2024	{{c1::Transcription}} is the process whereby a template DNA strand is copied into a functional RNA sequence and it is mediated by {{c2::RNA …
Published	07/30/2024	{{c1::Rifampin}} is a drug that inhibits RNA synthesis by binding to the {{c2::β subunit}} of bacterial DNA-dependent RNA polymerase leading to {…
Published	07/30/2024	Resistance to {{c2::Rifampin}} occurs from point mutations in {{c1::rpoB}}, the gene for the {{c3::β subunit of RNA polymerase}}.
Published	07/30/2024	{{c1::Chloramphenicol and Macrolides}} interfere with mRNA translation by binding to the {{c2::50S subunit}} and blocking peptide bond formation.
Published	07/30/2024	{{Tetracyclines (T)}} interfere with mRNA translation by binding to the {{c2::30S subunit}} and preventing the binding of the incoming charg…
Published	07/30/2024	The most important resistance mechanism of bacteria to tetracycline is via {{c1::enzymatic inactivation}}
Published	07/30/2024	Charged tRNA unit carrying amino acid 6 binds to the acceptor site on the 70S ribosomePeptidyl tRNA at the donor site, with amino acid 1-5, then binds…
Published	07/30/2024	{{c1::T::T/F}} Resistance to erythromycin is usually plasmid-encoded.
Published	07/30/2024	{{c1::Enterobacteriaceae}} can produce esterases that hydrolize {{c2::macrolides}}
Published	07/30/2024	Macrolide-lincosamide-streptogramin / MLS-type B, resistance occurs from a shared {{c1::ribosomal binding site}}
Published	07/30/2024	{{c1::Aminoglycosides}} bind to the {{c2::30S}} subunit within the cell.
Published	07/30/2024	{{c1::Aminoglycosides}} block protein synthesis by blocking {{c2::peptide bond formation}} resulting in the production of {{c3:: nonfun…
Published	07/30/2024	{{c1::T::T/F}} Telithromycin is effective against macrolide resistant strains.
Published	07/30/2024	{{c1::Quinupristin-Dalfopristin}} is a combination of two {{c2::streptogramins::antibiotic class}}.
Published	07/30/2024	Quinupristin, a streptogramin {{c1::B::A/B}}, makes up {{c2::30}}% of Quinupristin-Dalfopristin.
Published	07/30/2024	Dalfopristin, a streptogramin {{c1::A::A/B}}, makes up {{c2::70}}% of Quinupristin-Dalfopristin
Published	07/30/2024	{{c2::Quinupristin-Dalfopristin}} is rapidly bactericidal for most susceptible organisms except {{c1::Enterococcus faecium}}.
Published	07/30/2024	{{c1::Macrolides}} and {{c1::tetracyclines}} allow initiation and mRNA translation to begin but act by inhibiting peptide elongation.
Published	07/30/2024	{{c1::Intrinsic mechanisms of resistance}} refer to the innate ability of a bacterial species to resist antimicrobial agents through inherent structur…
Published	07/30/2024	{{c1::Impermeability}}Intrinsic mechanism of resistance that relies on the hydrophobic or hydrophilic nature of the antibiotic
Published	07/30/2024	{{c1::Impermeability}}Intrinsic mechanism of resistance that relies on the cell wall composition, biofilms, or porin channels.
Published	07/30/2024	{{c1::Biofilms}}Intrinsic mechanism of resistance that relies on the attachment of bacterial communities to a solid surface in an exopolysaccharide ma…
Published	07/30/2024	{{c1::Efflux}}Intrinsic mechanism of resistance that relies on the function as transporter proteins for the extrusion of toxic substances and antibiot…
Published	07/30/2024	{{c1::Enzymatic inactivation}}Intrinsic mechanism of resistance that relies on the enzymes to destroy the antimicrobial agents before they can reach t…
Published	07/30/2024	{{c1::Acquired mechanisms of resistance}} refer to resistance via natural selection: target organisms acquire, evolve, and disseminate resis…
Published	07/30/2024	Acquired mechanism of resistanceExamples {{c1::Chromosomal mutations}}Quinolones & Beta lactams{{c2::Enzymatic ta…
Published	07/30/2024	{{c1::Lateral gene transfer}} is the most important strategy for bacteria to spread antimicrobial resistance.
Published	07/30/2024	{{c1::Plasmids::Mobile element}} are circular DNA elements that replicate independently of the chromosome and can acquire and exchange information wit…
Published	07/30/2024	{{c1::Transposons (Tns)::Mobile element}} are DNA elements that encode transposition and excision functions and can transpose from one place on the ch…
Published	07/30/2024	{{c1::Integrons::Mobile element}} are genetic elements that capture mobile gene cassettes by site-specific recombination
Published	07/30/2024	{{c1::Insertion sequences (Iss)::Mobile element}} are short DNA sequences that act as a simple transposable element.
Published	07/30/2024	{{c1::Insertion sequences (Iss)::Mobile element}} are the smallest transposable elements (relative).
Published	07/30/2024	{{c1::Transposase}} catalyzes the enzymatic reaction that would allow your insertion sequence to move the regulatory protein which then stimulates or …
Published	07/30/2024	Plasmids are non essential for bacterial survival and impart no particular advantage{{c1::F::T/F}}
Published	07/30/2024	Integrons are usually mobilized on plasmid and Tns.{{c1::T::T/F}}
Published	07/30/2024	Peptidoglycan is composed of alternating {{c1::N-acetylglucosamine}} and {{c2::N-acetylmuramic acid}}.
Published	07/30/2024	The N-acetylmuramic acid unit in peptidoglycan ends in a 5 amino-acid peptide which terminates in {{c1::D-alanyl-D-alanine}} and {{c2::mediates t…
Published	07/30/2024	{{c1::Penicillin binding proteins (PBPs)}} remove the {{c2::terminal alanine}} in the process of forming a cross-link with a nearby peptide; this…
Published	07/30/2024	1. Synthesis of precursors in the cytoplasm2. Transport of lipid-bound precursors across the cytoplasmic membrane3. Insertion of glycan units into the…
Published	07/30/2024	{{c1::D-cycloserine::antibiotic}} and {{c1::bacitracin::antibiotic}} inhibit Steps {{c2::1 &2}} of peptidoglycan biosynthesis.
Published	07/30/2024	{{c1::Beta-lactams::antibiotic}} and {{c1::glycopeptides::antibiotic}} inhibit Steps {{c2::3 & 4}} of peptidoglycan biosynthesis.
Published	07/30/2024	{{c1::Beta-lactam compounds}} share the same {{c3::4-membered lactan ring}} and include the following: - {{c2::penicillins}}- {{c2::cep…
Published	07/30/2024	Beta-lactam compoundsMOA{{c1::covalently bind to PBPs which inhibits transpeptidation reaction, and consequently, peptidoglycan s…
Published	07/30/2024	{{c1::Inactivation of antibiotic by beta-lactamase}} is the most common mecahanism of resistance to {{c2::beta-lactam compounds::antibiotic}}.
Published	07/30/2024	Effectivity of beta-lactamases produced by {{c1::Staphylococcus aureus}}, {{c1::Haemophilus influenzae}}, {{c1::Escherichia coli}}:&nbs…
Published	07/30/2024	Effectivity of {{c1::AmpC beta-lactamase}} produced by {{c2::Pseudomonas aeruginosa}} and {{c2:Enterobacter sp.}}: {{c3::penicilli…
Published	07/30/2024	Effectivity of {{c1::extended-spectrum-beta-lactamase}} produced by {{c2:Enterobacteriaceae}}: {{c3::penicillins = cephalosporins}}
Published	07/30/2024	{{c1::Carbapenems}} are hydrolyzed by {{c2::metallo-beta-lactamases}} and {{c2::carbapenemases}}.
Published	07/30/2024	{{c1::Altered PBP::MOR against beta-lactam compounds}} is the basis of methicillin resistance in {{c2::Staphyloccocus (MRSA)}} and of penicillin …
Published	07/30/2024	{{c1::Impaired penetration of antibiotics::MOR against beta-lactam compounds}} occurs only in {{c2::Gram-negative::Gram-negative/Gram-positive}} …
Published	07/30/2024	Beta-lactam antibiotics enter Gram-negative organisms via outer membrane protein channels called {{c1::porins}}.
Published	07/30/2024	Structure of {{c1::penicillins}}:- {{c2::thiazolidine ring attached to beta-lactam ring that carries a secondary amino group (RNH-)}}
Published	07/30/2024	Beta-lactamases attack the {{c1::thiazolidine ring}} and {{c2::beta-lactam ring}}. This is responsible for resistance of bacteria against penicil…
Published	07/30/2024	Penicillins have the greatest activity against {{c1::Gram-positive organisms}}, {{c1::Gram-negative cocci}}, and {{c1::non-beta-lactama…
Published	07/30/2024	Penicillins have the little activity against {{c1::Gram-negative rods}}.
Published	07/30/2024	The nucleus of {{c1::cephalosporins}}, {{c2::7-aminocephalosporanic acid}}, closely resembles that of {{c3::penicillin}}.
Published	07/30/2024	{{c1::F::T/F}} Cephalosporins have high intrinsic microbial activity.
Published	07/30/2024	The attachment of {{c1::R groups}} in cephalosporins and cephamycins increases their intrinsic antimicrobial activity.
Published	07/30/2024	Generations {{c1::3&4}} of cephalosporins and cephamycins have more coverage for {{c2::gram-negative::gram-negative/gram-positive}} micr…
Published	07/30/2024	{{c1::Monobactams}} are drugs with a {{c2::monocyclic beta-lactam ring::structure}}.
Published	07/30/2024	The activity of monobactams is limited to {{c1::aerobic Gram-negative organisms}}.
Published	07/30/2024	{{c1::Clavulanic acid}}, {{c1::sulbactam}}, and {{c1::tazobactam}} are {{c2::beta-lactamase inhibitors::antibiotic class}} that are most act…
Published	07/30/2024	Clavulanic acid, sulbactam, and tazobactam are also active against the {{c1::chromosomal}} beta-lactamases of {{c2::Bacteroides fragilis}} a…
Published	07/30/2024	Clavulanic acid, sulbactam, and tazobactam are not good inhibitors of {{c1::class C}} beta-lactamases such as those produced by: - {{c2…
Published	07/30/2024	Avilbactam is a {{c1::beta-lactamase inhibitor::antibiotic class}} has activity against {{c2::Ambler Class A}} and {{c2::Class C}} beta…
Published	07/30/2024	{{c1::Beta-lactamase inhibitors}} are available only in fixed combinations with specific {{c2::penicillins}} and {{c2::cephalosporins}}.
Published	07/30/2024	{{c1::Beta-lactamase inhibitors}} are used as {{c2::empirical therapy}} for infections and are excreted through the {{c3::renal}} route.
Published	07/30/2024	{{c1::Carbapenems}} have the broadest spectrum of activity within the {{c2::beta-lactam}} class and are stable against most {{c3::Ambler Cla…
Published	07/30/2024	{{c1::T::T/F}} Carbapenems have a high affinity to PBPs.
Published	07/30/2024	Carbapenems include:- {{c1::Doripenem}}- {{c1::Ertapenem}}- {{c1::Imipenem}}- {{c1::Meropenem}}
Published	07/30/2024	The activity of {{c1::glycopeptide antibiotics}} such as {{c2::Teicoplanin}}, {{c2::Telavancin}}, and {{c2::Vancomycin}} is limite…
Published	07/30/2024	{{c1::Vancomycin::antibiotic}} is isolated from {{c2::Amycolatopsis orientalis::bacterium}}.
Published	07/30/2024	VancomycinMOA{{c1::inhibits cell wall synthesis by binding firmly to the D-ala-D-ala terminus of the peptidoglycan pentapeptide}}…
Published	07/30/2024	{{c1::Para-aminobenzoic acid}} is a substrate used by bacteria to synthesize {{c2::folic acid}} which is used for {{c3::nucleic acid synthes…
Published	07/30/2024	The main enzymes targeted by antibiotics that inhibit folate synthesis  are {{c1::dihydropteroate synthase}} and {{c1::dihydrofolate re…
Published	07/30/2024	SulfonamidesMOA{{c1::inhibit dihydropteroate synthase during folate synthesis, thereby preventing the conversion of PABA into dih…
Published	07/30/2024	Sulfonamides are usually given with {{c1::trimethoprim}} or {{c1::pyrimethamine}}.
Published	07/30/2024	TrimethoprimMOA{{c1::selectively inhibits bacterial dihydrofolic acid reductase}}MOR1. {{c2::reduced cell permeability for…
Published	07/30/2024	The mixture of trimethoprim with {{c1::sulfamethoxazole}} produces a {{c2::bactericidal}} effect which causes total cell death and eradicati…
Published	07/30/2024	Bacterial DNA replication requires the enzymes {{c1::topoisomerases I, II, III, and IV}}.
Published	07/30/2024	Fluoroquinolones work by {{c1::binding to topoisomerase II and IV::MOA}} to inhibit {{c2::DNA replication}}.
Published	07/30/2024	Intrinsic mechanisms of resistance include: - {{c1::impermeability}}- {{c1::biofilms}}- {{c1::efflux}}- {{c1::enzymatic activ…
Published	07/30/2024	Acquired mechanisms of resistance include: - {{c1::target site modification}}- {{c1::chromosomal mutations}}- {{c1::enzymatic targ…
Published	07/30/2024	Mechanisms of Lateral Gene Transfer:- {{c1::conjugation}}- {{c1::transformation}}- {{c1::transduction}}
Published	07/30/2024	{{c1::Conjugation::mechanism of lateral gene transfer}} occurs via direct contact (through a pilus).
Published	07/30/2024	{{c1::Transduction::mechanism of lateral gene transfer}} is the uptake of DNA through infection with a bacteriophage carrying resistance genes.
Published	07/30/2024	{{c1::Transformation::mechanism of lateral gene transfer}} is the uptake naked DNA from the surrounding environment.
Published	07/30/2024	Resistance Mechanisms for Tetracyclines: - {{c1::impaired influx/increased effllux by an active subunit transport protein pump}}- {{c1::ribosome …
Published	07/30/2024	Resistance Mechanisms for Erythromycin: - {{c1::reduced permeability of the cell membrane or active efflux}}- {{c1::production (by Enterobacteria…
Published	07/30/2024	{{c1::F::T/F}} Cross-resistance is not complete between erythromycin and other macrolides so it is alright to prescribe another macrolide if there is …
Published	07/30/2024	Erythromycin also shares methylase production as a resistance mechanism with structurally unrelated compounds such as {{c1::clindamycin}} and&nbs…
Published	07/30/2024	Resistance Mechanisms Against Aminoglycosides: - {{c1::transferase enzyme inactivates the aminoglycoside (adenylylation, acetylation, or pho…
Published	07/30/2024	{{c1::Telithromycin}} is a {{c2::ketolide::antibiotic class}} and has a higher affinity to bacterial ribosomes than other macrolides.
Published	07/30/2024	Erythromycin is a {{c1::macrolide::antibiotic class}}.
Published	07/30/2024	Linezolid is a/an {{c1::oxazolidinone::antibiotic class}}.
Published	07/30/2024	Linezolid binds at the {{c1::23S ribosomal RNA}} of the {{c2::50S subunit}}.
Published	07/30/2024	Linezolid inhibits protein synthesis by {{c1::preventing formation of the ribosome complex that initiates protein synthesis}}.
Published	07/30/2024	Resistance to linezolid is secondary to {{c1::mutation on the binding site}}.
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