14.5 Drug Resistance
3 min read•june 18, 2024
is a critical issue in microbiology. Microorganisms adapt to survive antimicrobial drugs, making infections harder to treat. This phenomenon affects bacteria, viruses, and fungi, limiting treatment options and increasing healthcare costs.
Resistance develops through intrinsic characteristics, genetic changes, or gene acquisition. Selective pressure from antimicrobial use accelerates this process. Understanding these mechanisms is crucial for developing strategies to combat the growing threat of drug-resistant infections.
Mechanisms and Impact of Drug Resistance
Drug resistance and antimicrobial effectiveness
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- develops when microorganisms adapt to survive and multiply despite the presence of an antimicrobial drug that would typically inhibit or kill them (bacteria, viruses, fungi)
- Diminishes the effectiveness of antimicrobial treatments making infections harder to control
- Necessitates higher doses or alternative drugs to combat resistant infections
- Resistant microorganisms can disseminate leading to increased prevalence of drug-resistant infections (###-resistant_Staphylococcus_aureus_()_0###)
- Presents a major threat to public health by limiting treatment options
- Results in increased healthcare expenditures and extended hospital stays
- can emerge against various drug classes encompassing antibiotics, antivirals, and antifungals (, , )
- The (MIC) of drugs often increases as resistance develops
Development of antimicrobial resistance
- Intrinsic resistance: Certain microorganisms have inherent characteristics that render them naturally resistant to specific antimicrobials
- Gram-negative bacteria's outer membrane functions as a barrier conferring intrinsic resistance to certain antibiotics ()
- Acquired resistance: Microorganisms gain resistance through genetic alterations or acquisition of resistance genes
- Mutations in genes targeted by antimicrobials can modify drug binding sites or decrease drug uptake ( resistance in )
- enables resistance genes to propagate among microorganisms via mechanisms including:
- : Exchange of genetic material through direct cell-to-cell contact (plasmid-mediated resistance)
- : Incorporation of naked DNA from the surrounding environment (antibiotic resistance in )
- : Transfer of genetic material mediated by bacteriophages (phage-mediated resistance in Escherichia coli)
- Selective pressure: Exposure to antimicrobials favors the survival and growth of resistant strains
- Inappropriate or excessive use of antimicrobials accelerates the development and spread of resistance (antibiotic overuse in agriculture)
Multidrug Resistance and Superbugs
- occurs when microorganisms develop resistance to multiple classes of antimicrobial drugs
- Often results from the accumulation of multiple resistance mechanisms or the acquisition of
- are strains of bacteria that have become resistant to multiple types of antibiotics
- Pose significant challenges in healthcare settings and can lead to severe, difficult-to-treat infections
- The recognizes the interconnectedness of human, animal, and environmental health in addressing antimicrobial resistance
- programs aim to optimize antimicrobial use and prevent the development of resistance
Resistance Mechanisms Across Microorganisms
Mechanisms of resistance across microorganisms
- Bacteria:
- Enzymatic modification or breakdown of antimicrobials
- catalyze the hydrolysis of beta-lactam antibiotics rendering them ineffective ( ())
- Alteration of drug targets
- Mutations in genes encoding drug target proteins can diminish drug binding affinity (fluoroquinolone resistance in )
- Reduced drug uptake or increased efflux
- Modifications in cell wall or membrane permeability restrict drug entry ( resistance in )
- Efflux pumps actively expel antimicrobials from the cell (tetracycline resistance in E. coli)
- Enzymatic modification or breakdown of antimicrobials
- Viruses:
- Mutations in viral enzymes targeted by antiviral drugs
- Mutations in reverse transcriptase can impart resistance to nucleoside reverse transcriptase inhibitors (NRTIs) ( resistance)
- Alterations in viral proteins that interact with antiviral drugs
- Changes in viral envelope proteins can decrease the efficacy of entry inhibitors ( resistance in HIV)
- Viral genome diversity and high mutation rates
- Rapid replication and error-prone viral polymerases contribute to the emergence of resistant variants (influenza virus resistance to )
- Mutations in viral enzymes targeted by antiviral drugs
- Fungi:
- Overexpression of drug target enzymes
- Increased production of enzymes like lanosterol 14α-demethylase can offset the inhibitory effects of azole antifungals ( resistance in Candida albicans)
- Mutations in drug target genes
- Alterations in ergosterol biosynthesis pathway enzymes can reduce the binding affinity of antifungal agents ( resistance in )
- overexpression
- Enhanced activity of efflux pumps, such as and , can actively remove antifungal drugs from fungal cells (azole resistance in Candida species)
- Overexpression of drug target enzymes
Key Terms to Review (101)
Acinetobacter baumannii: Acinetobacter baumannii is a Gram-negative, opportunistic pathogen commonly associated with hospital-acquired infections. It is known for its remarkable ability to develop resistance to multiple antibiotics.
Adamantanes: Adamantanes are a class of organic compounds characterized by a rigid, three-dimensional structure consisting of a cage-like arrangement of carbon atoms. This unique molecular structure gives adamantanes distinctive physical and chemical properties that make them valuable in various applications, particularly in the field of drug resistance.
Amikacin: Amikacin is an aminoglycoside antibiotic used to treat severe bacterial infections. It works by binding to bacterial ribosomes, inhibiting protein synthesis and leading to cell death.
Aminoglycoside resistance: Aminoglycoside resistance is the ability of bacteria to survive and proliferate despite the presence of aminoglycoside antibiotics. This resistance can occur through various mechanisms such as enzymatic modification, efflux pumps, or target site mutations.
Aminopenicillins: Aminopenicillins are a class of broad-spectrum beta-lactam antibiotics derived from penicillin. They are effective against both Gram-positive and some Gram-negative bacteria.
Antibiotic Stewardship: Antibiotic stewardship refers to the coordinated efforts to promote the responsible and appropriate use of antibiotics in healthcare settings. It aims to optimize clinical outcomes, minimize the development of antibiotic-resistant bacteria, and ensure the long-term effectiveness of these crucial antimicrobial agents.
Antibiotic stewardship is a critical component in the context of drug resistance, as the overuse and misuse of antibiotics can contribute to the emergence and spread of resistant pathogens, rendering these life-saving drugs less effective.
Antibiotic-Resistant Genes: Antibiotic-resistant genes are genetic elements that confer the ability of bacteria to survive and thrive in the presence of antibiotics, which are normally used to kill or inhibit their growth. These genes are a major concern in the context of 14.5 Drug Resistance, as they contribute to the growing problem of antimicrobial resistance worldwide.
Antimicrobial Resistance: Antimicrobial resistance refers to the ability of microorganisms, such as bacteria, viruses, and fungi, to resist the effects of antimicrobial drugs, including antibiotics, antivirals, and antifungals. This phenomenon is a growing global public health concern as it can lead to the failure of standard treatments, increased healthcare costs, and the spread of infections.
Azoles: Azoles are a class of synthetic organic compounds that contain a five-membered heterocyclic ring with at least one nitrogen atom. They are widely used as antifungal agents, targeting specific enzymes involved in fungal cell membrane synthesis and disrupting the integrity of the cell membrane.
Benzimidazoles: Benzimidazoles are a class of antimicrobial drugs that inhibit the synthesis of microtubules, disrupting cell division. They are commonly used against parasitic worms and fungi.
Beta-Lactamases: Beta-lactamases are enzymes produced by bacteria that confer resistance to beta-lactam antibiotics, such as penicillins and cephalosporins, by hydrolyzing the beta-lactam ring and rendering the antibiotics ineffective. These enzymes play a crucial role in the ability of bacteria to achieve genetic diversity, develop drug resistance, and exhibit virulence factors.
Candida glabrata: Candida glabrata is a species of yeast that is an opportunistic pathogen, meaning it can cause infections in humans, particularly in immunocompromised individuals. It is a common cause of candidiasis, a type of fungal infection that can affect various parts of the body.
Capreomycin: Capreomycin is an antibiotic used primarily to treat multi-drug resistant tuberculosis (MDR-TB). It inhibits protein synthesis by binding to the bacterial ribosome.
Carbapenem: Carbapenems are a class of broad-spectrum beta-lactam antibiotics highly effective against many Gram-positive and Gram-negative bacteria. They are often used as a last resort for treating severe bacterial infections that are resistant to other antibiotics.
Carbapenem resistance: Carbapenem resistance is the ability of bacteria to withstand the effects of carbapenem antibiotics, which are often used as a last resort for treating severe infections. This resistance can lead to limited treatment options and higher mortality rates.
Carbapenem-resistant Enterobacteriaceae (CRE): Carbapenem-resistant Enterobacteriaceae (CRE) are a group of Gram-negative bacteria that have developed resistance to carbapenem antibiotics. These bacteria are known for causing severe infections and being difficult to treat due to their multidrug resistance.
Carbapenemases: Carbapenemases are enzymes produced by certain bacteria that hydrolyze carbapenem antibiotics, rendering them ineffective. These enzymes contribute significantly to antibiotic resistance in Gram-negative bacteria.
Carbapenems: Carbapenems are a class of broad-spectrum beta-lactam antibiotics highly effective against many gram-positive and gram-negative bacteria. They are often used as a last-resort treatment for severe or high-risk bacterial infections.
Cdr1p: Cdr1p is a protein that plays a crucial role in drug resistance mechanisms in various organisms, particularly in the context of fungal infections. It is a member of the ATP-binding cassette (ABC) transporter family and functions as an efflux pump, actively transporting drugs and other toxic substances out of the cell, thereby reducing their intracellular concentration and conferring resistance.
Cephalosporins: Cephalosporins are a class of β-lactam antibiotics that inhibit bacterial cell wall synthesis and are used to treat a wide range of infections. They are structurally and functionally similar to penicillins but are often more resistant to β-lactamases.
Clavulanic acid: Clavulanic acid is a beta-lactamase inhibitor that enhances the effectiveness of beta-lactam antibiotics. It is often combined with penicillins to overcome bacterial resistance.
Concentrated animal feeding operations (CAFOs): Concentrated Animal Feeding Operations (CAFOs) are large-scale industrial agricultural facilities that house and feed a high density of livestock. They are associated with significant environmental and public health concerns, including the spread of drug-resistant bacteria.
Conjugation: Conjugation is a process of genetic exchange between two prokaryotic cells, typically bacteria, where genetic material is transferred from one cell to another. This process allows for the sharing of genetic information and the acquisition of new traits, contributing to the genetic diversity of asexual prokaryotes.
Cross-resistance: Cross-resistance occurs when a microorganism resistant to one antimicrobial drug also becomes resistant to another drug, often due to similar mechanisms of action or genetic factors. This phenomenon can complicate treatment options and contribute to the spread of multidrug-resistant infections.
Drug resistance: Drug resistance is the reduction in effectiveness of a medication in curing a disease or condition. It occurs when microorganisms such as bacteria, viruses, fungi, and parasites evolve to withstand drugs that once successfully treated them.
Drug Resistance: Drug resistance refers to the ability of a microorganism, such as a bacterium, virus, or fungus, to withstand the effects of a drug that would normally be effective in treating an infection caused by that microorganism. This phenomenon arises from genetic changes or adaptations that allow the microorganism to survive and thrive in the presence of the drug.
Echinocandin: Echinocandins are a class of antifungal drugs that target and disrupt the fungal cell wall by inhibiting the enzyme 1,3-β-D-glucan synthase, which is responsible for the synthesis of 1,3-β-D-glucan, an essential component of the fungal cell wall. This mechanism of action makes echinocandins particularly effective against Candida species and other fungal pathogens.
Efflux pump: Efflux pumps are protein-based transport systems located in cell membranes that expel toxic substances, including antimicrobial drugs, out of cells. They play a crucial role in conferring drug resistance to bacteria.
Enterobacter spp.: Enterobacter spp. are a group of Gram-negative, facultatively anaerobic bacteria commonly found in the intestinal tract of humans and animals. They are known for causing opportunistic infections and demonstrating significant drug resistance.
Enterococcus: Enterococcus is a genus of Gram-positive, facultatively anaerobic bacteria that are commonly found in the human gastrointestinal and urogenital tracts. These bacteria are known for their ability to survive in a wide range of environmental conditions and their potential to develop antibiotic resistance, making them an important consideration in the context of drug resistance, urogenital tract infections, and digestive system health.
Enterococcus faecium: Enterococcus faecium is a Gram-positive bacterium commonly found in the human gut. It is notable for its role in hospital-acquired infections and its resistance to many antibiotics.
ESBLs: ESBLs, or Extended-Spectrum Beta-Lactamases, are enzymes produced by certain bacteria that confer resistance to a wide range of beta-lactam antibiotics, including penicillins, cephalosporins, and monobactams. This resistance mechanism poses a significant challenge in the treatment of bacterial infections.
ESKAPE pathogens: ESKAPE pathogens are a group of bacteria known for their high rates of antibiotic resistance and propensity to cause hospital-acquired infections. The acronym stands for Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter spp.
Extended-Spectrum Beta-Lactamases: Extended-spectrum beta-lactamases (ESBLs) are enzymes produced by certain bacteria that confer resistance to a wide range of beta-lactam antibiotics, including penicillins, cephalosporins, and monobactams. These enzymes are capable of hydrolyzing and inactivating a broad spectrum of beta-lactam antibiotics, making infections caused by ESBL-producing bacteria challenging to treat.
Extended-spectrum β-lactamases (ESBLs): Extended-spectrum β-lactamases (ESBLs) are enzymes produced by certain bacteria that confer resistance to a wide range of β-lactam antibiotics, including penicillins and cephalosporins. These enzymes can hydrolyze the antibiotic, rendering it ineffective.
Extensively drug-resistant Mycobacterium tuberculosis: Extensively drug-resistant Mycobacterium tuberculosis (XDR-TB) is a form of tuberculosis that is resistant to at least four of the core anti-TB drugs. This makes it more difficult to treat and control compared to other forms of TB.
Fluconazole: Fluconazole is an antifungal medication used to treat various fungal infections. It works by inhibiting the synthesis of ergosterol, an essential component of fungal cell membranes.
Fluconazole: Fluconazole is an antifungal medication used to treat a variety of fungal infections. It works by interfering with the fungal cell membrane, disrupting the fungal cell's ability to maintain its structure and function, ultimately leading to the death of the fungal cells.
Fluoroquinolones: Fluoroquinolones are a class of broad-spectrum antibiotics that inhibit bacterial DNA gyrase and topoisomerase IV, essential enzymes for DNA replication. They are used to treat various bacterial infections including those of the respiratory, urogenital, and digestive systems.
Fluoroquinolones: Fluoroquinolones are a class of broad-spectrum antibacterial drugs that are widely used to treat a variety of bacterial infections. They are known for their ability to effectively target and inhibit the essential bacterial enzymes, DNA gyrase and topoisomerase IV, which are crucial for DNA replication and cell division.
Glycopeptides: Glycopeptides are a class of antibiotics that inhibit bacterial cell wall synthesis by binding to peptidoglycan precursors. They are particularly effective against Gram-positive bacteria.
Glycosylation: Glycosylation is the enzymatic process that attaches glycans to proteins, lipids, or other organic molecules. It plays a crucial role in the proper folding and stability of many proteins, impacting their function and interactions.
HIV: HIV (Human Immunodeficiency Virus) is a virus that targets the immune system, specifically CD4 cells (T cells), leading to a progressive failure of the immune system. If left untreated, HIV can lead to AIDS (Acquired Immunodeficiency Syndrome).
Horizontal gene transfer: Horizontal gene transfer is the movement of genetic material between organisms other than by the vertical transmission of DNA from parent to offspring. It plays a significant role in the evolution and adaptation of microbes.
Horizontal Gene Transfer: Horizontal gene transfer (HGT) is the transfer of genetic material between organisms other than via reproduction. It is a key process that allows the rapid spread of traits, such as antibiotic resistance, across different species of prokaryotes, and is an important mechanism driving evolution and adaptation in microbial communities.
Isoniazid: Isoniazid is an antibiotic used primarily to treat and prevent tuberculosis. It works by inhibiting the synthesis of mycolic acids, essential components of the bacterial cell wall.
Kanamycin: Kanamycin is an aminoglycoside antibiotic that inhibits bacterial protein synthesis by binding to the 30S ribosomal subunit. It is commonly used to treat infections caused by Gram-negative bacteria.
Klebsiella pneumoniae: Klebsiella pneumoniae is a Gram-negative, encapsulated bacterium that can cause severe infections, particularly in the lungs and urinary tract. It is known for its resistance to multiple antibiotics, making infections difficult to treat.
Lamivudine: Lamivudine is a nucleoside reverse transcriptase inhibitor (NRTI) used in the treatment of HIV and hepatitis B infections. It works by inhibiting the reverse transcriptase enzyme, which is essential for the replication of the virus, thereby preventing the virus from multiplying and spreading within the host's cells.
Lincosamides: Lincosamides are a class of antibiotics that inhibit bacterial protein synthesis by binding to the 50S ribosomal subunit. They are particularly effective against Gram-positive bacteria and anaerobes.
Maraviroc: Maraviroc is a type of antiretroviral drug used in the treatment of HIV infection. It works by blocking the CCR5 co-receptor, which the HIV virus uses to enter and infect CD4+ T cells, thereby preventing viral entry and replication.
Mdr1p: Mdr1p, also known as P-glycoprotein (P-gp), is a transmembrane protein that functions as an efflux pump, actively transporting a wide range of substrates, including many drugs, out of cells. It plays a crucial role in the context of drug resistance, as its overexpression can confer multidrug resistance in various cell types.
Methicillin: Methicillin is a beta-lactam antibiotic used to treat bacterial infections caused by susceptible Gram-positive bacteria. It is most notable for its role in the development of methicillin-resistant Staphylococcus aureus (MRSA).
Methicillin-resistant S. aureus (MRSA): Methicillin-resistant S. aureus (MRSA) is a type of Staphylococcus aureus bacterium that is resistant to several widely used antibiotics, making infections difficult to treat. It is particularly notorious for its resistance to methicillin and other beta-lactam antibiotics.
Methicillin-resistant Staphylococcus aureus (MRSA): Methicillin-resistant Staphylococcus aureus (MRSA) is a type of Staphylococcus bacteria that has developed resistance to methicillin and other beta-lactam antibiotics. It is known for causing difficult-to-treat infections in humans.
Methicillin-Resistant Staphylococcus aureus (MRSA): Methicillin-Resistant Staphylococcus aureus (MRSA) is a strain of the common bacterium Staphylococcus aureus that has developed resistance to many antibiotics, including the antibiotic methicillin. This resistance makes MRSA infections particularly challenging to treat and a significant public health concern.
The term MRSA is directly relevant to the topics of 14.5 Drug Resistance, 14.6 Testing the Effectiveness of Antimicrobials, and 16.3 Modes of Disease Transmission. MRSA's resistance to antibiotics is a prime example of drug resistance, while the ability to effectively test for and identify MRSA is crucial for controlling its spread and transmission.
Minimum Inhibitory Concentration: The minimum inhibitory concentration (MIC) is the lowest concentration of an antimicrobial agent that is required to inhibit the visible growth of a microorganism under defined in vitro conditions. It is a crucial parameter in understanding the effectiveness of antimicrobial agents and their potential for controlling microbial growth in various contexts, such as infection treatment, disinfection, and assessing drug resistance.
Monobactams: Monobactams are a class of beta-lactam antibiotics characterized by a monocyclic beta-lactam ring. They are effective primarily against aerobic Gram-negative bacteria.
MRSA: MRSA (Methicillin-resistant Staphylococcus aureus) is a type of Gram-positive bacterium that is resistant to several widely used antibiotics, making it difficult to treat. It commonly causes skin and soft tissue infections but can lead to more severe invasive diseases.
Multidrug Resistance: Multidrug resistance (MDR) is a phenomenon in which microorganisms, such as bacteria or cancer cells, develop the ability to withstand the effects of multiple, structurally and functionally distinct antimicrobial or anticancer drugs. This acquired resistance poses a significant challenge in the treatment of infectious diseases and cancer.
Multidrug-resistant microbes (MDRs): Multidrug-resistant microbes (MDRs) are pathogens that have acquired resistance to multiple antimicrobial drugs. This resistance makes infections caused by these microbes difficult to treat.
Multidrug-resistant Mycobacterium tuberculosis (MDR-TB): Multidrug-resistant Mycobacterium tuberculosis (MDR-TB) is a form of tuberculosis caused by bacteria that are resistant to at least isoniazid and rifampin, the two most effective first-line drugs. MDR-TB poses significant treatment challenges and requires longer, more complex therapy.
Mycobacterium tuberculosis: Mycobacterium tuberculosis is a pathogenic bacterial species in the Mycobacteriaceae family, responsible for causing tuberculosis (TB). It primarily affects the lungs but can also infect other parts of the body.
One Health Approach: The One Health approach is a collaborative, multisectoral, and transdisciplinary approach that aims to achieve optimal health outcomes by recognizing the interconnectedness between humans, animals, and the environment. It emphasizes the need for coordinated efforts across various disciplines to address complex health challenges that arise at the interface of these domains.
Pan-resistance: Pan-resistance is the condition where a microorganism is resistant to all available antimicrobial agents. This resistance makes infections extremely difficult to treat.
Penicillin-binding proteins (PBPs): Penicillin-binding proteins (PBPs) are a group of enzymes found in bacterial cell membranes that are essential for synthesizing and remodeling the cell wall. They are the target sites for beta-lactam antibiotics such as penicillin.
Penicillins: Penicillins are a group of antibiotics derived from Penicillium fungi, effective against many Gram-positive bacteria. They inhibit bacterial cell wall synthesis, leading to cell lysis and death.
Penicillins: Penicillins are a class of antibiotics derived from the Penicillium fungus. They are widely used to treat a variety of bacterial infections by interfering with the synthesis of the bacterial cell wall, ultimately leading to cell lysis and death. Penicillins are a crucial component in understanding the mechanisms of antibacterial drugs and the growing issue of drug resistance.
Phosphorylation: Phosphorylation is the process of adding a phosphate group to a molecule, often mediated by enzymes. It plays a crucial role in cellular signaling and energy transfer.
Plasmids: Plasmids are small, circular, double-stranded DNA molecules that exist independently of the chromosomal DNA in bacteria. They often carry genes beneficial for survival, such as antibiotic resistance.
Pneumonia: Pneumonia is an infection that inflames the air sacs in one or both lungs, which may fill with fluid or pus. It can be caused by bacteria, viruses, or fungi and results in symptoms such as cough, fever, and difficulty breathing.
Polymyxins: Polymyxins are a class of antibiotics that target the cell membranes of Gram-negative bacteria. They are especially effective against multi-drug resistant strains.
Polymyxins: Polymyxins are a group of cationic polypeptide antibiotics that disrupt the cell membrane of gram-negative bacteria, leading to cell lysis and death. They are considered a last-resort treatment option due to their potential for nephrotoxicity and neurotoxicity.
Porin channels: Porin channels are proteins located in the outer membrane of Gram-negative bacteria that allow the passive diffusion of small molecules, including nutrients and waste products. They play a critical role in bacterial resistance to antibiotics by controlling the entry of these drugs.
Pseudomonas aeruginosa: Pseudomonas aeruginosa is a Gram-negative, opportunistic pathogen that can cause serious infections in humans. It is known for its resistance to antibiotics and ability to thrive in various environments.
Rifampin: Rifampin is an antibiotic commonly used to treat bacterial infections, including tuberculosis and certain types of meningitis. It inhibits RNA synthesis by binding to the bacterial DNA-dependent RNA polymerase.
Rifampin: Rifampin is a broad-spectrum antibiotic used to treat various bacterial infections. It is particularly effective against mycobacterial infections, such as tuberculosis, and is a key component in the treatment of these diseases. Rifampin's mechanism of action and its role in drug resistance and respiratory tract infections make it a crucial topic in the study of microbiology.
Staphylococcus aureus: Staphylococcus aureus is a Gram-positive bacterium commonly found on the skin and in the nasal passages. It can cause a range of infections from minor skin conditions to severe diseases like pneumonia and sepsis.
Stenotrophomonas maltophila: Stenotrophomonas maltophila is a Gram-negative, multidrug-resistant bacterium that primarily infects immunocompromised individuals. It is often associated with hospital-acquired infections and can cause respiratory, bloodstream, and urinary tract infections.
Streptococcus clavuligerus: Streptococcus clavuligerus is a bacterium known for producing clavulanic acid, a potent inhibitor of beta-lactamase enzymes. This property makes it significant in combating antibiotic resistance.
Streptococcus pneumoniae: Streptococcus pneumoniae is a Gram-positive bacterium often found in the human respiratory tract, capable of causing diseases such as pneumonia, meningitis, and sinusitis. It exhibits virulence factors like a polysaccharide capsule that help it evade the immune system.
Sulfa drugs: Sulfa drugs are a group of synthetic antibacterial medications that contain the sulfonamide group. They inhibit bacterial growth by interfering with folic acid synthesis.
Sulfonamide resistance: Sulfonamide resistance is the ability of bacteria to survive and proliferate despite the presence of sulfonamide antibiotics. This occurs through various mechanisms, including genetic mutations and acquisition of resistance genes.
Sulfones: Sulfones are a class of synthetic antimicrobial agents primarily used to treat mycobacterial infections such as leprosy. They inhibit the synthesis of dihydrofolic acid by competing with para-aminobenzoic acid (PABA) in bacteria.
Superbugs: Superbugs are strains of bacteria that have developed resistance to multiple antibiotics, making them difficult to treat. They arise due to genetic mutations and the misuse or overuse of antimicrobial drugs.
Superbugs: Superbugs are strains of bacteria, viruses, fungi, and other microorganisms that have developed resistance to most or all of the antimicrobial drugs commonly used to treat the infections they cause. This resistance makes them extremely difficult to control and eradicate, posing a significant threat to public health.
Target mimicry: Target mimicry is a strategy used by some bacteria to evade the action of antimicrobial drugs. It involves the production of molecules that resemble the drug's target, thereby sequestering the drug and preventing it from interacting with its actual target in the pathogen.
Transduction: Transduction is the process by which genetic material is transferred from one organism to another through the action of a virus or viral vector. This process can have significant implications in the context of viral life cycles, genetic diversity in asexual prokaryotes, genetic engineering, and the development of drug resistance.
Transformation: Transformation is the process by which genetic material, such as DNA, is introduced into a cell, allowing the cell to acquire new genetic traits or characteristics. This process is a fundamental concept in microbiology and genetic engineering, as it enables the modification and manipulation of the genetic makeup of organisms.
Transposons: Transposons, also known as jumping genes, are DNA sequences that can change their position within the genome. They play a significant role in genetic diversity and evolution by causing mutations and altering the cell's genetic identity.
Trimethoprim: Trimethoprim is an antibiotic used primarily to treat bacterial infections, particularly in the urogenital and digestive systems. It works by inhibiting bacterial DNA synthesis.
Tuberculosis: Tuberculosis (TB) is a contagious bacterial infection caused by Mycobacterium tuberculosis. It primarily affects the lungs but can spread to other organs.
Vancomycin: Vancomycin is a glycopeptide antibiotic used to treat serious bacterial infections caused by Gram-positive bacteria. It inhibits cell wall synthesis by binding to the D-alanyl-D-alanine terminus of cell wall precursor units.
Vancomycin: Vancomycin is a glycopeptide antibiotic used to treat severe bacterial infections, particularly those caused by Gram-positive bacteria that are resistant to other antibiotics. It is an important tool in the fight against antimicrobial resistance and is a key consideration across various topics in microbiology and infectious disease management.
Vancomycin-intermediate S. aureus (VISA): Vancomycin-intermediate S. aureus (VISA) is a strain of Staphylococcus aureus with intermediate resistance to vancomycin. This reduced susceptibility complicates treatment options for infections.
Vancomycin-resistant enterococci (VRE): Vancomycin-resistant enterococci (VRE) are strains of the Enterococcus bacteria that have developed resistance to vancomycin, an antibiotic used to treat serious infections. VRE infections are particularly concerning in healthcare settings due to limited treatment options.
Vancomycin-resistant S. aureus (VRSA): Vancomycin-resistant S. aureus (VRSA) is a strain of Staphylococcus aureus that has developed resistance to the antibiotic vancomycin. This makes it particularly challenging to treat infections caused by this bacterium.
XDR-TB: XDR-TB stands for Extensively Drug-Resistant Tuberculosis, a form of tuberculosis that is resistant to at least four of the core anti-TB drugs. It is more challenging to treat than multi-drug resistant TB (MDR-TB) and poses a significant public health threat.
β-lactam ring: A β-lactam ring is a four-membered lactam (a cyclic amide) that forms the core structure of several antibiotic classes, including penicillins and cephalosporins. Its presence is critical for the antibacterial activity of these antibiotics by inhibiting cell wall synthesis.
β-lactamases: β-lactamases are enzymes produced by bacteria that hydrolyze the β-lactam ring of β-lactam antibiotics, rendering them ineffective. They are a major mechanism of bacterial resistance to these drugs.
β-lactams: β-lactams are a class of broad-spectrum antibiotics that contain a β-lactam ring in their molecular structure. They work by inhibiting the synthesis of bacterial cell walls, leading to cell death.