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Aminoglycosides

Aminoglycosides

Aminoglycosides are a class of antibiotics including gentamicin, tobramycin, amikacin, neomycin, plazomicin, and streptomycin. The class binds the 30S ribosomal subunit to inhibit bacterial protein synthesis Synthesis Polymerase Chain Reaction (PCR). Unlike other medications with a similar mechanism of action, aminoglycosides are bactericidal Bactericidal Penicillins. Aminoglycosides provide coverage against aerobic gram-negative pathogens, including Pseudomonas Pseudomonas Pseudomonas is a non-lactose-fermenting, gram-negative bacillus that produces pyocyanin, which gives it a characteristic blue-green color. Pseudomonas is found ubiquitously in the environment, as well as in moist reservoirs, such as hospital sinks and respiratory equipment. Pseudomonas. Aminoglycosides can also be used synergistically with inhibitors of bacterial cell wall Cell wall The outermost layer of a cell in most plants; bacteria; fungi; and algae. The cell wall is usually a rigid structure that lies external to the cell membrane, and provides a protective barrier against physical or chemical agents. Cell Types: Eukaryotic versus Prokaryotic synthesis Synthesis Polymerase Chain Reaction (PCR) (e.g., β lactams) for gram-positive Gram-Positive Penicillins pathogens. Use is limited by serious side effects, including nephrotoxicity Nephrotoxicity Glycopeptides and ototoxicity Ototoxicity Damage to the ear or its function secondary to exposure to toxic substances such as drugs used in chemotherapy; immunotherapy; or radiation. Glycopeptides.

Last updated: 8 Jul, 2021

Editorial responsibility: Stanley Oiseth, Lindsay Jones, Evelin Maza

Contents

Chemistry and Pharmacodynamics

Chemical structure

  • Contains a hexose-ring nucleus Nucleus Within a eukaryotic cell, a membrane-limited body which contains chromosomes and one or more nucleoli (cell nucleolus). The nuclear membrane consists of a double unit-type membrane which is perforated by a number of pores; the outermost membrane is continuous with the endoplasmic reticulum. A cell may contain more than one nucleus. The Cell: Organelles
  • Glycosidic linkages to various amino sugars 
  • Gentamicin is the prototypical drug.
Chemical structure of gentamicin

Chemical structure of gentamicin:
a core hexose ring (2-deoxystreptamine in the center) with 2 amino sugar molecules attached

Image: “Gentamicin” by NEUROtiker. License: Public Domain

Mechanism of action

  • Aminoglycosides bind BIND Hyperbilirubinemia of the Newborn to the bacterial 30S ribosomal subunit.
  • Disruption of bacterial protein synthesis Synthesis Polymerase Chain Reaction (PCR) by:
    • Prevention of initiation complex formation Initiation Complex Formation Oxazolidinones
    • Misreading of mRNA mRNA RNA sequences that serve as templates for protein synthesis. Bacterial mRNAs are generally primary transcripts in that they do not require post-transcriptional processing. Eukaryotic mRNA is synthesized in the nucleus and must be exported to the cytoplasm for translation. Most eukaryotic mRNAs have a sequence of polyadenylic acid at the 3′ end, referred to as the poly(a) tail. The function of this tail is not known for certain, but it may play a role in the export of mature mRNA from the nucleus as well as in helping stabilize some mRNA molecules by retarding their degradation in the cytoplasm. RNA Types and Structure → production of faulty protein → damage to the cell
    • Inhibition of translocation
  • The process is lethal for the bacterial cell → bactericidal Bactericidal Penicillins (concentration-dependent killing)
  • The postantibiotic effect allows for continued suppression Suppression Defense Mechanisms of bacterial growth.
  • Note: Aminoglycosides are transported across the cell membrane Cell Membrane A cell membrane (also known as the plasma membrane or plasmalemma) is a biological membrane that separates the cell contents from the outside environment. A cell membrane is composed of a phospholipid bilayer and proteins that function to protect cellular DNA and mediate the exchange of ions and molecules. The Cell: Cell Membrane via an oxygen-dependent process (not effective against anaerobic bacteria Anaerobic Bacteria Nitroimidazoles).
Site of action for aminoglycosides

The site of action for aminoglycosides, which target the 30S ribosomal subunit
tRNA tRNA The small RNA molecules, 73-80 nucleotides long, that function during translation (translation, genetic) to align amino acids at the ribosomes in a sequence determined by the mRNA (RNA, messenger). There are about 30 different transfer rnas. Each recognizes a specific codon set on the mRNA through its own anticodon and as aminoacyl trnas (RNA, transfer, amino Acyl), each carries a specific amino acid to the ribosome to add to the elongating peptide chains. RNA Types and Structure: transfer RNA RNA A polynucleotide consisting essentially of chains with a repeating backbone of phosphate and ribose units to which nitrogenous bases are attached. RNA is unique among biological macromolecules in that it can encode genetic information, serve as an abundant structural component of cells, and also possesses catalytic activity. RNA Types and Structure
mRNA mRNA RNA sequences that serve as templates for protein synthesis. Bacterial mRNAs are generally primary transcripts in that they do not require post-transcriptional processing. Eukaryotic mRNA is synthesized in the nucleus and must be exported to the cytoplasm for translation. Most eukaryotic mRNAs have a sequence of polyadenylic acid at the 3′ end, referred to as the poly(a) tail. The function of this tail is not known for certain, but it may play a role in the export of mature mRNA from the nucleus as well as in helping stabilize some mRNA molecules by retarding their degradation in the cytoplasm. RNA Types and Structure: messenger RNA RNA A polynucleotide consisting essentially of chains with a repeating backbone of phosphate and ribose units to which nitrogenous bases are attached. RNA is unique among biological macromolecules in that it can encode genetic information, serve as an abundant structural component of cells, and also possesses catalytic activity. RNA Types and Structure

Image by Lecturio. License: CC BY-NC-SA 4.0

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Pharmacokinetics

Absorption Absorption Absorption involves the uptake of nutrient molecules and their transfer from the lumen of the GI tract across the enterocytes and into the interstitial space, where they can be taken up in the venous or lymphatic circulation. Digestion and Absorption

  • Poor enteral absorption Absorption Absorption involves the uptake of nutrient molecules and their transfer from the lumen of the GI tract across the enterocytes and into the interstitial space, where they can be taken up in the venous or lymphatic circulation. Digestion and Absorption 
  • Usually given IV or IM

Distribution

  • Hydrophilic → volume of distribution ↑ with fluid overload (e.g., edema Edema Edema is a condition in which excess serous fluid accumulates in the body cavity or interstitial space of connective tissues. Edema is a symptom observed in several medical conditions. It can be categorized into 2 types, namely, peripheral (in the extremities) and internal (in an organ or body cavity). Edema, ascites Ascites Ascites is the pathologic accumulation of fluid within the peritoneal cavity that occurs due to an osmotic and/or hydrostatic pressure imbalance secondary to portal hypertension (cirrhosis, heart failure) or non-portal hypertension (hypoalbuminemia, malignancy, infection). Ascites)
  • Crosses the placenta Placenta A highly vascularized mammalian fetal-maternal organ and major site of transport of oxygen, nutrients, and fetal waste products. It includes a fetal portion (chorionic villi) derived from trophoblasts and a maternal portion (decidua) derived from the uterine endometrium. The placenta produces an array of steroid, protein and peptide hormones (placental hormones). Placenta, Umbilical Cord, and Amniotic Cavity
  • Does not cross the blood-brain barrier Blood-brain barrier Specialized non-fenestrated tightly-joined endothelial cells with tight junctions that form a transport barrier for certain substances between the cerebral capillaries and the brain tissue. Systemic and Special Circulations
  • Poor penetration Penetration X-rays into:

Excretion

  • Clearance is correlated with renal function (↓ glomerular filtration Glomerular filtration The kidneys are primarily in charge of the maintenance of water and solute homeostasis through the processes of filtration, reabsorption, secretion, and excretion. Glomerular filtration is the process of converting the systemic blood supply into a filtrate, which will ultimately become the urine. Glomerular Filtration → ↑ half-life Half-Life The time it takes for a substance (drug, radioactive nuclide, or other) to lose half of its pharmacologic, physiologic, or radiologic activity. Pharmacokinetics and Pharmacodynamics).
  • Approximately 99% is unchanged in the urine Urine Liquid by-product of excretion produced in the kidneys, temporarily stored in the bladder until discharge through the urethra. Bowen Disease and Erythroplasia of Queyrat.
  • Can be removed with hemodialysis Hemodialysis Procedures which temporarily or permanently remedy insufficient cleansing of body fluids by the kidneys. Crush Syndrome

Indications

Antimicrobial coverage

  • Aerobic gram-negative bacteria Bacteria Bacteria are prokaryotic single-celled microorganisms that are metabolically active and divide by binary fission. Some of these organisms play a significant role in the pathogenesis of diseases. Bacteriology, including:
    • Pseudomonas aeruginosa Pseudomonas aeruginosa A species of gram-negative, aerobic, rod-shaped bacteria commonly isolated from clinical specimens (wound, burn, and urinary tract infections). It is also found widely distributed in soil and water. P. Aeruginosa is a major agent of nosocomial infection. Pseudomonas
    • Escherichia coli Escherichia coli The gram-negative bacterium Escherichia coli is a key component of the human gut microbiota. Most strains of E. coli are avirulent, but occasionally they escape the GI tract, infecting the urinary tract and other sites. Less common strains of E. coli are able to cause disease within the GI tract, most commonly presenting as abdominal pain and diarrhea. Escherichia coli
    • Klebsiella Klebsiella Klebsiella are encapsulated gram-negative, lactose-fermenting bacilli. They form pink colonies on MacConkey agar due to lactose fermentation. The main virulence factor is a polysaccharide capsule. Klebsiella pneumoniae is the most important pathogenic species. Klebsiella pneumoniae
    • Haemophilus influenzae Haemophilus Influenzae A species of Haemophilus found on the mucous membranes of humans and a variety of animals. The species is further divided into biotypes I through viii. Haemophilus
    • Serratia Serratia A genus of gram-negative, facultatively anaerobic, rod-shaped bacteria that occurs in the natural environment (soil, water, and plant surfaces) or as an opportunistic human pathogen. Acute Cholangitis marcescens
    • Francisella tularensis
    • Brucella Brucella Brucellosis (also known as undulant fever, Mediterranean fever, or Malta fever) is a zoonotic infection that spreads predominantly through ingestion of unpasteurized dairy products or direct contact with infected animal products. Clinical manifestations include fever, arthralgias, malaise, lymphadenopathy, and hepatosplenomegaly. Brucella/Brucellosis
    • Yersinia Yersinia Yersinia is a genus of bacteria characterized as gram-negative bacilli that are facultative anaerobic with bipolar staining. There are 2 enteropathogenic species that cause yersiniosis, Y. enterocolitica and Y. pseudotuberculosis. Infections are manifested as pseudoappendicitis or mesenteric lymphadenitis, and enterocolitis. Yersinia spp./Yersiniosis
    • Campylobacter Campylobacter Campylobacter (“curved bacteria”) is a genus of thermophilic, S-shaped, gram-negative bacilli. There are many species of Campylobacter, with C. jejuni and C. coli most commonly implicated in human disease. Campylobacter
  • Mycobacteria Mycobacteria Mycobacterium is a genus of the family Mycobacteriaceae in the phylum Actinobacteria. Mycobacteria comprise more than 150 species of facultative intracellular bacilli that are mostly obligate aerobes. Mycobacteria are responsible for multiple human infections including serious diseases, such as tuberculosis (M. tuberculosis), leprosy (M. leprae), and M. avium complex infections. Mycobacterium
  • Synergistic effect with β-lactam antibiotics against:
    • Staphylococcus Staphylococcus Staphylococcus is a medically important genera of Gram-positive, aerobic cocci. These bacteria form clusters resembling grapes on culture plates. Staphylococci are ubiquitous for humans, and many strains compose the normal skin flora. Staphylococcus
    • Streptococcus Streptococcus Streptococcus is one of the two medically important genera of gram-positive cocci, the other being Staphylococcus. Streptococci are identified as different species on blood agar on the basis of their hemolytic pattern and sensitivity to optochin and bacitracin. There are many pathogenic species of streptococci, including S. pyogenes, S. agalactiae, S. pneumoniae, and the viridans streptococci. Streptococcus
    • Enterococcus Enterococcus Enterococcus is a genus of oval-shaped gram-positive cocci that are arranged in pairs or short chains. Distinguishing factors include optochin resistance and the presence of pyrrolidonyl arylamidase (PYR) and Lancefield D antigen. Enterococcus is part of the normal flora of the human GI tract. Enterococcus

Types of infections Infections Invasion of the host organism by microorganisms or their toxins or by parasites that can cause pathological conditions or diseases. Chronic Granulomatous Disease

  • Usually used in combination therapy for:
    • Endocarditis Endocarditis Endocarditis is an inflammatory disease involving the inner lining (endometrium) of the heart, most commonly affecting the cardiac valves. Both infectious and noninfectious etiologies lead to vegetations on the valve leaflets. Patients may present with nonspecific symptoms such as fever and fatigue. Endocarditis
    • Nosocomial pneumonia Nosocomial pneumonia Pneumonia in Children
    • Osteomyelitis Osteomyelitis Osteomyelitis is an infection of the bone that results from the spread of microorganisms from the blood (hematogenous), nearby infected tissue, or open wounds (non-hematogenous). Infections are most commonly caused by Staphylococcus aureus. Osteomyelitis
    • Urinary tract infections Urinary tract infections Urinary tract infections (UTIs) represent a wide spectrum of diseases, from self-limiting simple cystitis to severe pyelonephritis that can result in sepsis and death. Urinary tract infections are most commonly caused by Escherichia coli, but may also be caused by other bacteria and fungi. Urinary tract infections (UTIs) (including pyelonephritis Pyelonephritis Pyelonephritis is infection affecting the renal pelvis and the renal parenchyma. This condition arises mostly as a complication of bladder infection that ascends to the upper urinary tract. Pyelonephritis can be acute or chronic (which results from persistent or chronic infections). Typical acute symptoms are flank pain, fever, and nausea with vomiting. T Pyelonephritis and Perinephric Abscess)
  • Used as monotherapy for:
    • Multidrug-resistant (MDR) urinary tract infections Urinary tract infections Urinary tract infections (UTIs) represent a wide spectrum of diseases, from self-limiting simple cystitis to severe pyelonephritis that can result in sepsis and death. Urinary tract infections are most commonly caused by Escherichia coli, but may also be caused by other bacteria and fungi. Urinary tract infections (UTIs)
    • Plague Plague The plague is a bacterial infection caused by Yersinia pestis (Y. pestis), which primarily infects rodents. The disease is transmitted to humans via a flea bite. Inhalation of infectious droplets and handling infected animals or laboratory specimens are other means of transmission. The plague has 3 forms: bubonic (most common form), septicemic, and pneumonic. Yersinia pestis/Plague
    • Tularemia
  • Off-label:
    • Tobramycin: inhaled (for cystic Cystic Fibrocystic Change fibrosis Fibrosis Any pathological condition where fibrous connective tissue invades any organ, usually as a consequence of inflammation or other injury. Bronchiolitis Obliterans)
    • Amikacin and streptomycin: MDR Mycobacterium tuberculosis Mycobacterium tuberculosis Tuberculosis (TB) is an infectious disease caused by Mycobacterium tuberculosis complex bacteria. The bacteria usually attack the lungs but can also damage other parts of the body. Approximately 30% of people around the world are infected with this pathogen, with the majority harboring a latent infection. Tuberculosis spreads through the air when a person with active pulmonary infection coughs or sneezes. Tuberculosis

Adverse Effects and Contraindications

Adverse effects

  • Nephrotoxicity Nephrotoxicity Glycopeptides → accumulation of aminoglycosides in the renal cortex
  • Ototoxicity Ototoxicity Damage to the ear or its function secondary to exposure to toxic substances such as drugs used in chemotherapy; immunotherapy; or radiation. Glycopeptides (can be irreversible):
    • Amikacin: cochlear damage
    • Gentamicin, streptomycin, and tobramycin: vestibular damage
  • Neuromuscular blockade (rare)

Contraindications Contraindications A condition or factor associated with a recipient that makes the use of a drug, procedure, or physical agent improper or inadvisable. Contraindications may be absolute (life threatening) or relative (higher risk of complications in which benefits may outweigh risks). Noninvasive Ventilation

  • Allergy Allergy An abnormal adaptive immune response that may or may not involve antigen-specific IgE Type I Hypersensitivity Reaction to aminoglycosides
  • Pregnancy Pregnancy The status during which female mammals carry their developing young (embryos or fetuses) in utero before birth, beginning from fertilization to birth. Pregnancy: Diagnosis, Physiology, and Care
  • Neuromuscular disorders (e.g., myasthenia gravis Myasthenia Gravis Myasthenia gravis (MG) is an autoimmune neuromuscular disorder characterized by weakness and fatigability of skeletal muscles caused by dysfunction/destruction of acetylcholine receptors at the neuromuscular junction. MG presents with fatigue, ptosis, diplopia, dysphagia, respiratory difficulties, and progressive weakness in the limbs, leading to difficulty in movement. Myasthenia Gravis)

Drug interactions

  • Caution with nephrotoxic drugs: 
    • Amphotericin B Amphotericin B Macrolide antifungal antibiotic produced by streptomyces nodosus obtained from soil of the orinoco river region of venezuela. Polyenes
    • Vancomycin Vancomycin Antibacterial obtained from streptomyces orientalis. It is a glycopeptide related to ristocetin that inhibits bacterial cell wall assembly and is toxic to kidneys and the inner ear. Glycopeptides
    • NSAIDs NSAIDS Primary vs Secondary Headaches
    • Radiocontrast dye  
  • Loop diuretics Diuretics Agents that promote the excretion of urine through their effects on kidney function. Heart Failure and Angina Medication: ↑ risk of ototoxicity Ototoxicity Damage to the ear or its function secondary to exposure to toxic substances such as drugs used in chemotherapy; immunotherapy; or radiation. Glycopeptides
  • ↑ Risk of neuromuscular blockade:
    • Vecuronium Vecuronium Monoquaternary homolog of pancuronium. A non-depolarizing neuromuscular blocking agent with shorter duration of action than pancuronium. Its lack of significant cardiovascular effects and lack of dependence on good kidney function for elimination as well as its short duration of action and easy reversibility provide advantages over, or alternatives to, other established neuromuscular blocking agents. Neuromuscular Blockers
    • Botulinum toxin Botulinum toxin Toxic proteins produced from the species Clostridium botulinum. The toxins are synthesized as a single peptide chain which is processed into a mature protein consisting of a heavy chain and light chain joined via a disulfide bond. The botulinum toxin light chain is a zinc-dependent protease which is released from the heavy chain upon endocytosis into presynaptic nerve endings. Once inside the cell the botulinum toxin light chain cleaves specific snare proteins which are essential for secretion of acetylcholine by synaptic vesicles. This inhibition of acetylcholine release results in muscular paralysis. Botulism
    • Mecamylamine

Monitoring

  • Serum drug levels (peak and trough levels)
  • Renal function 
  • Hearing function
  • Visual acuity Visual Acuity Clarity or sharpness of ocular vision or the ability of the eye to see fine details. Visual acuity depends on the functions of retina, neuronal transmission, and the interpretative ability of the brain. Normal visual acuity is expressed as 20/20 indicating that one can see at 20 feet what should normally be seen at that distance. Visual acuity can also be influenced by brightness, color, and contrast. Ophthalmic Exam

Mechanism of Resistance

Several mechanisms of aminoglycoside resistance Resistance Physiologically, the opposition to flow of air caused by the forces of friction. As a part of pulmonary function testing, it is the ratio of driving pressure to the rate of air flow. Ventilation: Mechanics of Breathing:

  • Production of inactivating enzymes Enzymes Enzymes are complex protein biocatalysts that accelerate chemical reactions without being consumed by them. Due to the body’s constant metabolic needs, the absence of enzymes would make life unsustainable, as reactions would occur too slowly without these molecules. Basics of Enzymes:
    • Acetyltransferases
    • Phosphotransferases
    • Nucleotidyltransferases
  • Alterations at ribosomal binding sites ( methylation Methylation Addition of methyl groups. In histo-chemistry methylation is used to esterify carboxyl groups and remove sulfate groups by treating tissue sections with hot methanol in the presence of hydrochloric acid. . Glucocorticoids)
  • Efflux systems and ↓ cell permeability

Comparison of Antibiotics

The following table compares antibiotics, which inhibit bacterial protein synthesis Synthesis Polymerase Chain Reaction (PCR):

Table: Comparison of several classes of bacterial protein synthesis Synthesis Polymerase Chain Reaction (PCR) inhibitor antibiotics
Drug class Mechanism of action Coverage Adverse effects
Amphenicols
  • Gram positives
  • Gram negatives
  • Atypicals
  • GI upset
  • Optic neuritis Optic neuritis Inflammation of the optic nerve. Commonly associated conditions include autoimmune disorders such as multiple sclerosis, infections, and granulomatous diseases. Clinical features include retro-orbital pain that is aggravated by eye movement, loss of color vision, and contrast sensitivity that may progress to severe visual loss, an afferent pupillary defect (Marcus-Gunn pupil), and in some instances optic disc hyperemia and swelling. Inflammation may occur in the portion of the nerve within the globe (neuropapillitis or anterior optic neuritis) or the portion behind the globe (retrobulbar neuritis or posterior optic neuritis). Cranial Nerve Palsies
  • Aplastic anemia Anemia Anemia is a condition in which individuals have low Hb levels, which can arise from various causes. Anemia is accompanied by a reduced number of RBCs and may manifest with fatigue, shortness of breath, pallor, and weakness. Subtypes are classified by the size of RBCs, chronicity, and etiology. Anemia: Overview and Types
  • Gray baby syndrome Gray Baby Syndrome Chloramphenicol
Lincosamides Lincosamides The lincosamides, lincomycin and clindamycin, are inhibitors of bacterial protein synthesis. Drugs in this class share the same binding site as that of macrolides and amphenicols; however, they differ in chemical structure. Lincosamides target the 50S ribosomal subunit and interfere with transpeptidation. Lincosamides
  • Gram-positive Gram-Positive Penicillins cocci Cocci Bacteriology:
    • MSSA
    • MRSA MRSA A strain of Staphylococcus aureus that is non-susceptible to the action of methicillin. The mechanism of resistance usually involves modification of normal or the presence of acquired penicillin binding proteins. Staphylococcus
    • Streptococcus Streptococcus Streptococcus is one of the two medically important genera of gram-positive cocci, the other being Staphylococcus. Streptococci are identified as different species on blood agar on the basis of their hemolytic pattern and sensitivity to optochin and bacitracin. There are many pathogenic species of streptococci, including S. pyogenes, S. agalactiae, S. pneumoniae, and the viridans streptococci. Streptococcus
  • Anaerobes Anaerobes Lincosamides
  • GI upset
  • Allergic reactions Allergic Reactions Type I hypersensitivity reaction against plasma proteins in donor blood Transfusion Reactions
  • Pseudomembranous colitis Colitis Inflammation of the colon section of the large intestine, usually with symptoms such as diarrhea (often with blood and mucus), abdominal pain, and fever. Pseudomembranous Colitis
Macrolides Macrolides Macrolides and ketolides are antibiotics that inhibit bacterial protein synthesis by binding to the 50S ribosomal subunit and blocking transpeptidation. These antibiotics have a broad spectrum of antimicrobial activity but are best known for their coverage of atypical microorganisms. Macrolides and Ketolides
  • Gram positives
  • Gram negatives
  • Atypicals
  • Mycobacterium Mycobacterium Mycobacterium is a genus of the family Mycobacteriaceae in the phylum Actinobacteria. Mycobacteria comprise more than 150 species of facultative intracellular bacilli that are mostly obligate aerobes. Mycobacteria are responsible for multiple human infections including serious diseases, such as tuberculosis (M. tuberculosis), leprosy (M. leprae), and M. avium complex infections. Mycobacterium avium complex
  • GI upset
  • QT prolongation
  • Hepatotoxicity Hepatotoxicity Acetaminophen
  • Myasthenia gravis Myasthenia Gravis Myasthenia gravis (MG) is an autoimmune neuromuscular disorder characterized by weakness and fatigability of skeletal muscles caused by dysfunction/destruction of acetylcholine receptors at the neuromuscular junction. MG presents with fatigue, ptosis, diplopia, dysphagia, respiratory difficulties, and progressive weakness in the limbs, leading to difficulty in movement. Myasthenia Gravis exacerbation
Oxazolidinones Oxazolidinones The oxazolidinones (linezolid and tedizolid) are bacterial protein synthesis inhibitors. Their unique binding site on the 23S ribosomal RNA of the 50S ribosome gives them zero cross-resistance with other antibiotics. Oxazolidinones
  • Bind BIND Hyperbilirubinemia of the Newborn to the 23S rRNA rRNA The most abundant form of RNA. Together with proteins, it forms the ribosomes, playing a structural role and also a role in ribosomal binding of mRNA and tRNAs. Individual chains are conventionally designated by their sedimentation coefficients. In eukaryotes, four large chains exist, synthesized in the nucleolus and constituting about 50% of the ribosome. RNA Types and Structure of the 50S subunit
  • Prevent initiation complex formation Initiation Complex Formation Oxazolidinones
 Gram-positive Gram-Positive Penicillins cocci Cocci Bacteriology:
  • MSSA
  • MRSA MRSA A strain of Staphylococcus aureus that is non-susceptible to the action of methicillin. The mechanism of resistance usually involves modification of normal or the presence of acquired penicillin binding proteins. Staphylococcus
  • VRE
  • Streptococcus Streptococcus Streptococcus is one of the two medically important genera of gram-positive cocci, the other being Staphylococcus. Streptococci are identified as different species on blood agar on the basis of their hemolytic pattern and sensitivity to optochin and bacitracin. There are many pathogenic species of streptococci, including S. pyogenes, S. agalactiae, S. pneumoniae, and the viridans streptococci. Streptococcus
rRNA rRNA The most abundant form of RNA. Together with proteins, it forms the ribosomes, playing a structural role and also a role in ribosomal binding of mRNA and tRNAs. Individual chains are conventionally designated by their sedimentation coefficients. In eukaryotes, four large chains exist, synthesized in the nucleolus and constituting about 50% of the ribosome. RNA Types and Structure: ribosomal RNA Ribosomal RNA The most abundant form of RNA. Together with proteins, it forms the ribosomes, playing a structural role and also a role in ribosomal binding of mRNA and tRNAs. Individual chains are conventionally designated by their sedimentation coefficients. In eukaryotes, four large chains exist, synthesized in the nucleolus and constituting about 50% of the ribosome. RNA Types and Structure
VRE: vancomycin Vancomycin Antibacterial obtained from streptomyces orientalis. It is a glycopeptide related to ristocetin that inhibits bacterial cell wall assembly and is toxic to kidneys and the inner ear. Glycopeptides-resistant Enterococcus Enterococcus Enterococcus is a genus of oval-shaped gram-positive cocci that are arranged in pairs or short chains. Distinguishing factors include optochin resistance and the presence of pyrrolidonyl arylamidase (PYR) and Lancefield D antigen. Enterococcus is part of the normal flora of the human GI tract. Enterococcus
Antibiotic sensitivity chart

Antibiotic sensitivity Sensitivity Binary classification measures to assess test results. Sensitivity or recall rate is the proportion of true positives. Blotting Techniques:
Chart comparing the microbial coverage of different antibiotics for gram-positive Gram-Positive Penicillins cocci Cocci Bacteriology, gram-negative bacilli Bacilli Shigella, and anaerobes Anaerobes Lincosamides.

Image by Lecturio. License: CC BY-NC-SA 4.0

References

  1. Avent ML, Rogers BA, Cheng AC, Paterson DL. (2011). Current use of aminoglycosides: indications, pharmacokinetics, and monitoring for toxicity. Intern Med J. 41(6):441–9. https://pubmed.ncbi.nlm.nih.gov/21309997/
  2. Pagkalis S, Mantadakis E, Mavros MN, Ammari C, Falagas ME. (2011). Pharmacological considerations for the proper clinical use of aminoglycosides. Drugs; 71(17):2277–94. https://pubmed.ncbi.nlm.nih.gov/22085385/
  3. Krause KM, Serio AW, Kane TR, Connolly LE. (2016). Aminoglycosides: An Overview. Cold Spring Harb Perspect Med; 6(6) https://pubmed.ncbi.nlm.nih.gov/27252397/
  4. LeBras M, Chow I, Mabasa VH, Ensom MH. (2016). Systematic Review of Efficacy, Pharmacokinetics, and Administration of Intraventricular Aminoglycosides in Adults. Neurocrit Care; 25(3):492–507. https://pubmed.ncbi.nlm.nih.gov/27043949/
  5. Leis JA, Rutka JA, Gold WL. (2015). Aminoglycoside-induced ototoxicity. CMAJ; 187(1):E52. https://pubmed.ncbi.nlm.nih.gov/25225217/
  6. Selimoglu E. (2007). Aminoglycoside-induced ototoxicity. Curr Pharm Des; 13(1):119–26. https://pubmed.ncbi.nlm.nih.gov/17266591/
  7. Lopez-Novoa JM, Quiros Y, Vicente L, Morales AI, Lopez-Hernandez FJ. (2011). New insights into the mechanism of aminoglycoside nephrotoxicity: an integrative point of view. Kidney Int; 79(1):33–45. https://pubmed.ncbi.nlm.nih.gov/20861826/
  8. Drew, R.H. (2020). Aminoglycosides. Bloom, A. (Ed.), UpToDate. Retrieved July 2, 2021, from https://www.uptodate.com/contents/aminoglycosides
  9. Block, M., Blanchard, D.L. (2020). Aminoglycosides. StatPearls. Retrieved July 2, 2021, from https://www.ncbi.nlm.nih.gov/books/NBK541105/
  10. Werth, B.J. (2020). Aminoglycosides. MSD Manual Professional Version. Retrieved July 2, 2021, from  https://www.msdmanuals.com/professional/infectious-diseases/bacteria-and-antibacterial-drugs/aminoglycosides
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