Antimicrobial Agents: Antibacterial Agents

antimicrobial agents

any chemical (drug) used to treat an infectious disease, either by inhibiting or by killing pathogens in vivo

antibiotic

a substance produced by a microorganism that is effective in killing or inhibiting the growth of other microorganisms

penicillin and cephalosporin

what drugs are examples of antibiotics produced by molds?

semisynthetic antibiotics

antibiotics that have been chemically modified to kill a wider variety of pathogens or reduce side effects

selective toxicity

refers to the a drug that is harmful to a pathogen without being harmful to the host

chemotherapy

refers to the use of drugs to treat a disease

narrow spectrum

a spectrum where drugs are effective against a few types of bacteria and can be used only if the causative organism is identified

broad spectrum

a spectrum where drugs are effective against several different classes of bacteria but can increase childhood asthma development and may give rise to drug resistance

extensive spectrum

a spectrum where drugs are effective against gram positive organisms and a significant number of gram negative organisms

zone of inhibition

used to determine whether an organism is sensitive, intermediate, or resistant to the drug through the Kirby-Bauer test

Minimal Inhibitory concentration (MIC)

the lowest concentration of drug capable of preventing microbial growth and can be estimated using the E test

Minimum bacterial concentration

the lowest concentration of a chemotherapeutic agent that kills bacteria

Multidrug therapy

refers to two or more drugs that may be used simultaneously to kill all the pathogens and prevent resistant mutant pathogens from emerging

B-lactamases

enzymes produced by bacteria that destroy the B-lactam ring

Antimicrobial stewardship

refers to interventions designed to promote the optimal use of antibiotic agents

B-lactam antibacterial

blocks the crosslinking of peptide chains during the biosynthesis of new peptidoglycan in the bacterial cell wall

penicillins

a bactericidal drug that interferes with the synthesis of bacterial cell walls and have maximum effect on bacteria that is actively dividing

natural penicillins

a narrow spectrum penicillin and has a susceptibility to penicillinases

penicillinase-resistant penicillin

a narrow spectrum penicillin against gram-positive bacteria and is used commonly for Staphylococcus aureus infections

methicillin, nafcillin, isoxazolyl penicillin

what antibiotics are under penicillinase-resistant penicillin?

aminopenicillin

a penicillin that is effective against gram negative bacteria as well as gram positive ones and are not resistant to penicillinases

carboxypenicillins

an extended spectrum penicillin that have greater activity against gram negative bacteria and have special advantage of activity against Pseudomonas aeruginosa

ureidopenicillins

a broader spectrum penicillin and are modifications of the structure of ampicillin

clavulanic acid

a class I B-lactamase inhibitor that is combined with amoxicillin

sulbactam

a class I B-lactamase inhibitor combined with ampicillin

tazobactam

a class I B-lactamase inhibitor combined with piperacillin that is more potent than sulbactam and has a slightly broader spectrum activity than clavulanic acid

cefuroxime

the first of a series of a-methoximinoacyl-substituted cephalosporin that constitute most of the third generation agents available for clinical use

carbapenems

among the most powerful antibacterial agents in use today that target the cell envelope and have an excellent activity against a broad spectrum of bacteria

thienamycin

a novel-lactam antibiotic first isolated and identified by researchers at Merck from fermentation of cultures of Streptomyces cattleya

meropenem

a second generation carbapenem that is resistant to most lactamases and has undergone the most extensive clinical evaluation

monobactam

a synthetic antibiotic that has only a single ring and is not fused to another ring

aztreonam

the first new member of the new class of antibiotics and binds with high affinity to PBP 3 in gram negative bacteria only

glycopeptides/ polypeptide antibiotic

it targets the cell envelope and has excellent activity against most aerobic and anaerobic gram positive bacteria

bacitracin

an antibiotic that isolated from a wound on girl named Margaret Tracy and is used is restricted to topical application for superficial infections

vancomycin

an antibiotic isolated from Streptomyces orientalis and is the drug of choice for Pseudomonas colitis caused by Clindamycin

isoniazid

an antibiotic that inhibits the synthesis of mycolic acid, a component of cell wall only the mycobacteria

ethambutol

an antibiotic that is only effective against mycobacteria that inhibits incorporation of mycolic acid and is used as a secondary drug to avoid resistance problems

aminoglycosides

bactericidal broad spectrum drugs that inhibit bacterial protein synthesis and are used to treat infections with members of the family Enterobacteriaceae

streptomycin

an aminoglycoside that is used as the 2nd line in treating tuberculosis and some zoonotic infections

neomycin

an aminoglycoside used for hepatic encephalopathy

tetracycline

a bacteriostatic broad spectrum drug that can exert their effect by targeting bacterial ribosomes and contains four fused rings with a system of conjugated double bonds

tetracycline

The following reactions are adverse effect of what antibiotic?: gastric discomfort, deposition in the base, primary dentition causing discoloration and hypoplasia of teeth, temporary stunting of growth, and hepatoxicity

lincosamides

an antibiotic that resembles sulfonamides in antibacterial spectrum used for abdominal and female genitourinary tract infections caused by B. fragilis

chloramphenicol

a bacteriostatic antibiotic isolated from Streptomyces venezuelae

streptogramins

an antibiotic effective against VRSA, MRSA, and VRE but has a side effect which is arthralgia-myalgia syndrome

daptomycin

an antibiotic produced by a Streptomyces roseosporus and is used to treat certain systemic and life-threatening infections caused by gram positive organisms

polymixin B and colistin

a cationic, surface active compounds that disrupt the permeability of both outer and cytoplasmic membranes of gram negative bacteria

Rifamycin

a narrow spectrum antibiotic with activity against gram positive and limited numbers of gram negative bacteria and is in combination therapy for tuberculosis

fluoroquinolones

a bactericidal broad spectrum antibiotic against gram positive and negative bacteria and blocks DNA replication

sulfonamides and sulfones

an antibiotic that inhibits the enzyme involved in production of dihydrofolic acid

trimethoprim

an antibiotic that inhibits the enzyme involved in the production of tetrahydrofolic acid

dapsone/acedapsone

an antibiotic used for erythema nodosum leprosum and is a sulfur derivative

clofazimine

an antibiotic used for leprosy that gives off side effects such as red-orange skin discoloration and erythema nodosum leprosum

leprosy

an infection known as Hansen's disease

trimethoprim

a structural analog of a portion of dihydrofolic acid and completely inhibits the synthesis of tetrahydrofolic acid