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Microbiology Test #3
Chapter 24 Antimicrobial Drugs
Terms in this set (238)
salvarsan an arsenic derivative that killed the causative agent of syphilis.
prontosil- active against staphylocci, streptococci, and other Gram positive.
Penicillium mold from which penicillin was extracted.
naturally produced substance from one microorganism to kill another microorganism.
a chemical substance synthesized from natural and man made components used to treat a disease.
the range of antimicrobial drug action.
useful for treating many groups of microorganisms, including gram positive and gram negative.
useful for a restricted group of microorganisms.
Five major targets for antimicrobial agents
cell wall, cell membrane, protein synthesis, nucleic acid synthesis, and folic acid synthesis.
How do sulfa drugs work?
by inhibiting folic acid synthesis due to competitive inhibition.
What kind of spectrum are sulfa drugs?
Broad spectrum but resistance is common now.
Sulfamethoxazole (SMZ) combined with trimethoprim (TMP) inhibit _______.
folic acid synthesis. Combination is called co-trimoxazole or Bactrim.
Sulfa drugs are ______ drugs.
Isoniazid is what type of drug?
What kind of spectrum is isoniazid?
How does isoniazid work?
inhibits cell wall synthesis in Mycobacterium by inhibiting the production of mycolic acid.
Isoniazid is used in combination with _____ and ______.
rifampin and ethambutol. Ethambutol is also a synthetic that has side effects including vision impairment.
How do quinolones work?
Blocks DNA synthesis in G+ and G- microorganisms.
used to treat UTI, gonorrhea, Chlamydia, and GI infections. Ciprofloxacin (Cipro) is safe for adults but does adversely affect cartilage development.
Ciprofloxacin (Cipro) is safe for adults but does adversely affect ______.
Beta Lactam class inhibit ________.
cell wall synthesis.
The beta lactam class commonality is
a beta lactam nucleus.
most popular but sensitive to stomach acid so it given intravenously. Inhibits cell wall synthesis.
more acid resistant so can be given orally. Inhibits cell wall synthesis.
Beta Lactams are active against
a variety of G+, including staph, strep, clostridia, and pneumococci. In higher concentrations they can work against G- diplococci and spirochetes.
Penicillin blocks the cross linking of
carbohydrates in the PEP layer during cell wall formation.
Two disadvantages to penicillin
anaphylactic reaction and penicillin resistant bacterial species
Many of the penicillin resistant organisms can produce
beta lactamases which inactivate beta lactam antibiotics. An example is penicillinase.
modifications of natural penicillin by introducing different side chains.
Semisynthetic penicillins extend
the spectrum of antimicrobial activity and they help reduce microbial resistance. Called semisynthetic because part of the antibiotic is produced by the mold and part is produced by man.
Semisynthetic penicillins are more resistant to
Amoxicillin when used with clavulanic acid is called
augmentin and the clavulanic acid inactivates penicillinase.
Cephalosporin is still a _______ class.
Cephalosporin and penicillin make up
50% of antibiotics produced. They also resemble penicillin.
Cephalosporins are used when
resistance is encountered and when penicillin allergy exists.
Cephalosporins have a _______
broader antibacterial spectrum. they also last longer in the body.
Cephalosporins are resistant to many
beta lactamases which means they can fight off penicillinase.
Over the years cephalosporins have achieved targeting
How does cephalosporin work?
inhibiting cell wall.
Monobactams are still beta lactams and they are _____ spectrum
Monobactams are active against
aerobic, G- rods especially those involved in nosocomial infections and bacterial meningitis.
cell wall synthesis.
Nosocomial infections are
Major side effects of Monobactams are
interference with platelet function and severe bleeding
Antibiotics are produced by some
fungi and bacteria due to competition in the environment.
More than half of our antibiotics are produced by species of
Streptomyces which are filamentous bacteria that live in the soil.
cell wall synthesis.
Vancomycin is used
intravenously against Staphylococcus infections where penicillin is resisted. It's inactive against G-.
As drug resistance has spread among staphylococci,
the choices of antibiotics to use has decreased.
Vancomycin has become very important in treating resistant bacteria. It is often referred to as
the drug of last resort. There is now Vancomycin resistant bacteria.
Vancomycin serious side effects include
permanent kidney and hearing damage so it's used for serious infections.
Polypeptide antibiotics affect the
Bacitracin is extracted from
Bacitracin is toxic
internally so it's used topically against G+ as well as for the prevention of wound infections.
Bacitracin side effects:
can cause severe kidney damage.
Bacitracin when used in combination with polymyxin is called
Polymyxin works by
polypeptides that insert into the cell membrane increasing permeability leading to cell death.
Polymyxin is most active against
Aminoglycoside is an antibiotic that affect
Aminoglycoside work by
attach irreversibly to bacterial ribosomes, blocking the reading of the mRNA.
Aminoglycoside must be administered by
the first aminoglycoside; still occasionally prescribed for TB and some diseases caused by G- bacteria.
Major side effects for Streptomycin
damage to hearing leading to deafness.
Gentamicin in an aminoglycoside and it's currently used
for serious UTI involving G- bacteria.
Major side effect for Gentamicin
damage to kidney and hearing damage.
Chloramphenicol is ______ spectrum
wide variety of G+ and G- bacteria, several species of rickettsiae, and fungi.
Chloramphenicol is small in size
so it passes into tissues where it interferes with protein synthesis.
Chloramphenicol remains the drug of choice for
treating Typhoid fever. It is a serious drug for serious diseases.
Major side effect of Chloramphenicol
results in 1 in 40K people who take this medication. It is usually fatal it suppresses bone marrow activity.
Modern tetracyclines are
broad spectrum bacteriostatic.
2 common semisynthetic tetracyclines are
doxycline and minocycline.
Tetracylines seem to help in
Tetracycline overuse led to
teeth discoloration, elimination of normal flora, and stunted bone growth in children.
Tetracyclines are active
against a wide range of G- bacteria, chlamydial and rickettsial infections.
Macrolides are _______.
broad spectrum bacteriostatic.
a macrolide was isolated from a Streptomyces organism. It is effective in treating atypical pneumonia and Legionnaires disease. Recommended for use against G+ bacteria in people with penicillin allergies.
Side effects of erythromycin:
some minor interference with GI infections.
Important macrolide is
azithromycin (Zithromax) one of the best selling antibiotics.
Zithromax is a semisynthetic drug and has a _________ spectrum.
Oxazolidinones- this group of antibiotics again with _______ have only been around since 2000.
effective in treating MRSA, however it may produce allergic reactions and it toxic to mitochondria.
Linezolid and the other oxazolidinones are
used normally as the last resort.
Antibiotics that inhibit nucleic acid synthesis
interferes with the processes of DNA replication and transcription. Dangerous because it may effect host cells.
a semisynthetic bactericidal drug that affects transcription. Microbial resistance develops very fast, so it is used in combination with isioniazid and ethambutol for TB and leprosy.
Side effects of Rifampin
turns body fluids orange and may cause liver damage.
There are three ways we attack fungi
affect fungal sterols in the plasma membrane, affect fungal cell walls, inhibit nucleic acid synthesis.
Affect fungal sterols-
sterol is a component of the fungi plasma membrane. It is vital to the integrity of the plasma membrane, so if you damage sterols then the plasma membrane becomes too permeable and the cell dies.
affect fungal cell wall-
fungal cell walls have a compound that is unique to fungi and it is Beta Glucan. If beta glucan is not in the cell wall, the wall breaks. Some antibiotics work to inhibit the synthesis of Beta glucans.
inhibit nucleic acid synthesis-
this means the antibiotic interferes with the processes of DNA replication and transcription in the microorganisms.
Polygenes bind to
product of Streptomyces-used to treat infections of the oral cavity, vagina, or intestines.
drug choice for serious systemic infections, also from streptomyces. Side effects include kidney damage.
synthetic antifungal drug that inhibits an enzyme needed to form ergosterol in the plasma membrane.
Produced from a penicillium mold, interferes with mitosis by binding to microtubules, and used for superficial infections of skin/nails. Inhibit nucleic acid synthesis.
What does MRSA mean?
Multi-drug resistant Staphylococcus aureus
Methicillin resistant Staphylococcus aureus
MRSA refers to the
resistance of a strain of Staphylococcus aureus to the beta lactam class of antibiotics, which include methicillin and cephalosporin.
MRSA presents a treatment problem,
since the usual antibiotics used to treat S. aureus cannot be used. As a result, more toxic and expensive antibiotics are required.
One of the drugs used on MRSA is
vancomycin.(inhibits protein synthesis)
clusters of spherical cells
Resistant to drying out
Pathogenic Staphylococcus includes:
S. aureus is responsible for
forming abscesses with pus producing lesions, boils, acne, impetigo, and carbuncles associated with the skin.
Staphylococcus aureus is responsible for
pneumonia, osteomyelitis, endocarditis, cystitis, septicemia, pyelonephritis.
bone and bone marrow abscesses
inflamed urinary bladder
bacteria in blood
S. aureus can produce these toxic end products
coagulase, leukocidin, hemolysins, enterotoxin.
form blood clots that surround and protect the organism.
lyses white blood cells
lyses red blood cells
Vancomycin resistant staphylococcus aureus
Treatment for VRSA
linezolid- very harsh, inhibits protein synthesis. side effects: thrombocytopenia (abnormally small number of platelets resulting in the potential for increased bleeding and decreased ability for clotting), elevates liver enzyme, GI upsets- which are severe.
Classified by hemolytic activity
alpha "partial destruction" reduces RBCs, incomplete lysis of RBC, green zone around colonies non pathogenic. green halo around bacteria.
Beta "Complete destruction" serious strep. completely clear.
Streptococcus can produce a variety of extracellular metabolites
hemolysins (alpha & beta)-act on RBC's
Leucodins- destroy phagocytes
causes food poisoning
produces the antibiotic bacitracin (cell wall synthesis)
produces the antibiotics gramicidin and tyrocidin
produces the antibiotic polymyxin B.
Secrete powerful exotoxins
4 clinically important clostridium
C. tetani (tetanus)
C. difficle (pseudomembranous entercolitis [very hard to kill])
C. perfringens (Gas Gangrene)
C. botulinum (botulism)
Club shaped rods
Corynebacterium diphtheriae- the causative agent of diphtheria
Commonly found in Yogurt
Lactic-acid producing bacteria
Commerically used on dairy products
weakly Gram +
Mycobacterium tuberculosis-TB and leprosy
Teponema pallidum (syphillis)
Borrelia burgdorgeri (Lyme disease)
Responsible for 1 in 10 nosocomial infections
Capable of growing on soap residues, cap-liner adhesives, and antiseptics
Water in the cooling towers of air conditioning systems
What is an opportunistic pathogen
Not normally thought of a pathogen but will take advantage of environment to become a pathogen.
Always in pairs (diplococci)
Inhabit the mucous membranes of mammals
Neisseria gonorrhoeae (Gonorrhoeae)
Neisseria meningitides (Meningitis)
Mammalian parasite and pathogen
Bordetella pertussis (Whooping cough)
Poultry and cattle
Salmonella typhi (typhoid fever)
Human GI tract
Escherichia coli: causes UTIs, traveler's diarrhea, and foodborne diseases.
Facultative Anaerobic rods
catheters, saline irrigation solution, supposedly sterile solutions
Serratia marcescens- urinary and respiratory tract infections
Peritrichous (flagella all over)
Transmitted via fleas of rats and squirrels
Yersinia pestis (bubonic plague)
Curved rods w/ polar flagella
mucous membranes of the U.R. tract, mouth, vagina, and GI tract
Require blood as a nutrient
Haemophilus influenza (bacterial meningitis)
Obligate intracellular parasite
Lice, fleas, mites or ticks as carriers
Rocky Mt. Spotted fever
all species are parasites
Obligate intracellular parasites
What is the cause of nosocomial infections?
pseudomonas aeroginosa, staphylococcus aureus, serratia
Transmission of nosocomial infections?
hospital environments, sinks, medical apparatus
Symptoms of nosocomial infections
produce a lethal exotoxin, act similiar to diphtheria, causes tissue necrosis, inhibits phagocytosis
High risk pts for nosocomial infections
catheterized, immunosuppresive drugs, antibiotic therapy
Treatment for nosocomial infections
Carbenicillin and Gentamicin
Prevention for nosocomial infections
aseptic hand washing between every pt.
Cause of syphilis
Spirochete Treponema pallidum
Tansmission of syphilis
sexually transmitted/placental transfer
Primary stage symptoms for syphilis
seondary stage symptoms for syphilis
rash on skin
Latent stage symptoms for syphilis
Tertiary stage symptoms for syphilis
gummas (large ulcerous lesions)
Detection for syphilis
Treatment for syphilis
Cause of pertussis
Transmission of pertussis
Symptoms of pertussis
paroxysms of coughing with inspiratory sound called "whoop", cyanosis, hemorrhages of nose, eyes, and brain, secondary infections lead to brochopneumonia (85% fatal in children under 2 if untreated)
Detection of pertussis
Nasopharyngeal swabs on Bordet-Gengou agar (rich in starch and penicillin)
Treatment of pertussis
Prevention of pertussis
Cause of typhoid fever
Transmission of typhoid fever
foodborne or waterborne
symptoms of typhoid fever
fever, inflamed intestines, spleen enlargement, blood stools, accumulates in gall bladder
Detection of typhoid fever
examination of blood or stools, widal test-mix serum antibodies with known cell parts from salmonella and observe for agglutination
Treatment for typhoid fever
Ciprofloxacin and chloramphenicol
Prevention of typhoid fever
vaccine-good for 3 years
Cause of bubonic plague
Transmission of bubonic plague
septicemic from-rodent flea bites; pneumonia from-airborne
Symptoms of bubonic plague
enlarged lymph nodes (bubos)
Detection of bubonic plague
test for plague antibodies and observe Y. pestis in gram stain.
Treatment for bubonic plague
streptomycin or tetracycline
prevention for bubonic plague
vaccine, avoid handling wild rodents
cause of cholera
transmission of cholera
foodborne or waterborne
symptoms of cholera
profuse diarrhea (rice water stools), may lose up to 1L of fluid per hour, 70% fatal in untreated cases
Detection of cholera
isolate bacteria in stools
Treatment of cholera
Tetracycline or erythromycin
Prevention of cholera
Vaccine 50% effective, improve sanitation, cook/wash veggies, fruit, shellfish.
Cause of bacterial meningitis
Neisseria meningitides, Haemophilus influenza
Transmission of bacterial meningitis
airborne, highly contagious
Symptoms of bacterial meningitis
N. meningitides- URI, bacterial toxins in couple of hours cause death, 50% fatal
H. influenza- pneumonia infection, gets into blood to meninges, 95% mortality, affects children 6 wks to 2 years
Detection of bacterial meningitis
Treatment of bacterial meningitis
Rifampin and Chloramphenicol
Prevention of bacterial meningitis
Vaccine HIB developed in 1985.
Cause of toxic shock syndrome
transmission of toxic shock syndrome
Symptoms of toxic shock syndrome
Detection of toxic shock syndrome
Treatment of toxic shock syndrome
antibiotics and blood transfusions to get rid of bacteria
Prevention of toxic shock syndrome
sterile, less absorbent tampons, also affects males
Cause of bacterial pneumonia
streptococcus pneumonia (70% of cases), Mycoplasma pneumonia, Klebsiella pneumonia, Serratia marcescens
Transmission of bacterial pneumonia
airborne with lowered resistance pts.
Symptoms of bacterial pneumonia
air sacs fill with fluid
Detection of bacterial pneumonia
isolate from sputum, bile solubility test-use bile to induce lysis of pneumococci bacteria, capsule stain
Treatment of bacterial pneumonia
Prevention of bacterial pneumonia
Vaccine-Prevnar for Strep. pneumoniae (2,4,6,12 months)
Cause of tetanus
Trans. of tetanus
Symps of tetanus
Powerful neurotoxins that gets to CNS, painful and violent contractions of muscles of the neck and jaw, paralysis of thoracic muscles, respiratory or cardiac failure, 55-65% fatal
Detection of tetanus
isolation of bacterium, symptoms conclusive
Treat of tetanus
penicillin, muscle relaxants, antitoxins
prevention of tetanus
vaccine, booster shots every 7-10 yrs or sooner if you get a puncture wound.
Cause of Gas Gangrene
Clostridium Perfringens, Clostridium sp.
Trans of gas gangrene
contact with dead anaerobic tissue
symps of gas gangrene
fermenting releases gas and tears tissue apart, presses against blood vessels and blocks blood flow, turns tissues blue-black.
Detection of gas gangrene
treat of gas gangrene
amputation, antitoxins, antibiotics, hyperbaric oxygen chamber (3X oxygen to kill anaerobic bacteria)
Botulism is the most
powerful neurotoxin: one ounce would kill U.S. population, one pint entire world.
Cause of botulism
Transmission of botulism
soilborne, spores in canning
Cause of tuberculosis
Transmission of tuberculosis
Symptoms of tuberculosis
tubercles on lungs (clumps of wbcs, salts, and fibrous tissue), lungs are slowly eroded.
Detection of tuberculosis
Tuberculin (Mantoux) test, tine test, chest x-rays
Treatment for tuberculosis
Rifampin and isoniazid
Prevention of tuberculosis
Vaccine (BCG only approved in Europe)
Cause of food poisoning
Staphylococcus aureus, Salmonella sp. Escherichia coli
Transmission of food poisoning
food or waterborne
symptoms of food poisoning
cramps, nausea, vomiting, diarrhea
Detection of food poisoning
Nose swab on Mannitol salt agar, trace foods
Prevention of food poisoning
sterile food processing, refrigerate, cook meats thoroughly, thaw poultry and egg products in the refrigerator
Cause of anthrax
Transmission of anthrax
skin contact, contact with infected animals, airborne, food and waterborne.
Symptoms of anthrax cutaneous form-
itching, lesions, can survive
Symptoms of anthrax inhalation form-
fever, cough, fatigue, respiratory distress, death in 24-36 hours
Symptoms of anthrax GI form-
death in 2-5 days
Detection of anthrax
Isolate organism, gram stain
Treatment of anthrax
Prevention of anthrax
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