Micro 1-5 Flashcards
Invented Microscope? When?
Van Leeuwenhoek 1683
Anthrax Bacilli observed? When
Divine & Pollander. 1850
What did Pasture do?
Father of Micro; fermentation, steam steralization, and vaccine for rabies. 1857
Antiseptic surgery?
Lister
Discovered tubercle bacilli (TB) and vibrio cholera?
Koch
Discovery of penicillin by? When?
Fleming. 1929.
Concept of Immunity? When?
Jenner. 1796. (smallpox)
4 categories of bacteria?
bacteria, viruses, parasites, fungi
What are helminthes?
eukaryotic, multicelular, animal/worm, pass in feces
fungal infections?
athlete’s foot, jock itch, thrush
Cellulitis?
inflammation of the connective tissue
Gonococci
gonorrhea
Cl Tetani
tetanus
Cornebacterium diphtheriae
diptheria
E coli
UTI & dirrahea
Shigella
dysentery
Salmonella
Typhoid fever
Bordetella pertusis
whooping cough
Yersenia
plague
Mycobacterium
TB & leprosy
Treponema pallidum
syphiliis
Herpes Simplex (HSV)
cold sores on lips and genetal herpes
Varicella-Zoster
chicken pox, shingles
Adenovirus
URI, LRI, sore throat
Papilloma virus (HPV)
STD-Condyloma
Rhino virus
common cold
Parasitic Infections
Protozoal infections like amebic dysentery, toxoplasmosis and malaria; worm infestations.
Eukaryotes
central nucleus and intra cytoplasmic organelles but no cell wall
Prokaryotes
Cell wall, but no nucleus and no intra cytoplasmic organelles
Gram +
cell wall of peptidoglycan
Gram -
cell wall of lipopolysaccharide
Cell membrane of bacteria does not have…?
sterols; humans have cholesterol
Function of capsule?
resists phagocytosis
Function of pili?
found in Gram - for attatchment and conjugation.
Function of flagellae?
for movement
Function of glycocalyx?
slimy layer for adherence.
Facultative anaerobes?
with/out O2; energy by gylcolysis – ex. E Coli, Solmonella, Shigella
Obligate aerobes?
Only with O2 – ex. TB, pseudomonas
Obligate anaerobes?
No O2 – Cl Tetani
DNA of bacteria?
one haploid chromosome
Conjugation?
Mating 2 bacteria cells where DNA is transferred from F+ to F- cell; only plasmid is transferred.
Transduction?
DNA transferred by bacteriophage.
Gram Staining Procedure?
Crystal violet>H2O>Iodine (fixing)>Decolorize (ETOH)>Safranin
Acid Fast procedure? Why?
Carbolfuchsin>decolorize with acid (H2SO4), counterstain with Methylene Blue. Acid fast bacteria=red; others=blue. Due to presence of mycolic acid.
Normal flora in nose?
S. aureus
Normal flora in mouth?
S. viridans, S. mutans
Normal flora in gingival cervices?
bacteriods, acinomycosis, anaerobic organisms (can cause brain abcess..)
Normal flora in GIT?
H. pylori, lactobacilli, yeasts, C. diff, E. coli, proteus, P. auroginosa.
Convalescent carrier
Those who suffered a disease and spread infection during recovery.
Healthy carriers
Normal persons carrying pathogenic organisms w/out suffering from disease (asymptomatic)
Iatrogenic infection
physician or health care personnel introduced infection thru breach in infection control measures.
Nasocomial infection
acquired from hospital environment
Sources of infection? (5)
Man, animals, insects, soil & water
Modes of transmission? (7)
contact, inhalation, ingestion, inoculation, insect bite, placenta, breast milk
Routes of entry? (4)
skin, GI tract, Respiratory tract, Genito-Urinary tract
Stages of infection? (4)
Incubation, Prodromal, Specific, Recovery
Disease is caused by 2 major mechanisms?
Invasion & Inflammation, and Toxin production
Pathogenic features of bacteria?
adherence, invasion, inflammation, toxin production, intracellular survival
Adherence?
pili and glycocalyx
Invasion?
IgA protease, collagenase & hyaluranidase (degrades collagen and helps spread infection)
Inflammation?
pyogenic (pus) and granulomatous (cell mediated immune response by macrophace and Tcells)
Intracellular survival?
avoid phagocytosis & neutralizes antibodies
What are endotoxins?
part of cell wall – lipoplysacchardies in Gram - ; produce fever, shock and general symptoms.
What are exotoxins?
Secreted by bacteria and liberated into extracellular space; mostly Gram +
Toxoids?
inactivated exotoxins
Diptheria toxin
exotoxin of Gram + bacteria; causes cell death
Tetanus toxin
Gram +, neurotoxin, spastic paralysis of skeletal muscles.
Botulinum toxin
Gram +, neurotoxin; flacid paralysis of skeletal muscles
TSST
Gram +, by S. aureus – toxic shock
Enterotoxin by S. aureus
Gram +, food poisoning
Erythrogenic toxin
Gram +, responsible for red rashes in scarlet fever
Enterotoxin of E coli
Gram -, watery diarrhea
Verotoxin
Gram -, bloody diarrhea
Enterotoxin by Vibrio Cholera
Gram -, causes severe watery dirrahea
B pertusis toxins
Gram -, stimulate G proteins & cause persistent cough.
Innate Immunity
inborn & non specific
Acquired Immunity
acquired after birth & specific – T cells & macrophages
Examples of non specific defense (innate)
skin, mucous membranes, gastric aciditiy, mucociliary blank of respiratory tract and lysozymes in tears and saliva
Inflammatory response is characterized by…
dolar, rubor, calor and tumor
Increased blood flow is brought to the sight of injury by…
bradykinin & histamine
Diapedesis
movement of phagocytic cell from inside the blood vessles to extracellular spaces leaking out through endothelial cells.
During phagocytosis, 2 microbicidal agents are released. They are…
Super oxide radical and Hydrogen Peroxide
In Gram - infections, what else is producted as a microbicidal in addition to Super oxide radical and hydrogen peroxide?
Nitric oxide; over production causes vasodilation which is responsible for hypotension in septic shock.
Myeloperoxidase enzyme
produces hypochlorite ion which is the most powerful microbicidal agent (acts only in presence of O2)…responsible for GREEN COLOR of pus
Lysosomes contain…
lysozyme, myeloperoxidase, proteases, lipases & nucleases
Neutrophils
1st line of defense; not APC
Macrophages (monocytes)
2nd line of defense (only when neutrophils can’t do the job) APC
Complement
protein which kills the baceria and opsonizes bacteria to facilitate phagocytosis.
interferon
anti viral substance produced by leukocytes during viral infection to inhibit viral replication
Natural Killer (NK) cells
not involved in phagocytosis but kill viral infected cells (NO part in bacterial cells)
chronic granulomatous disease
phagocyte cannot kill the ingested microbes (NADPH oxidase) deficiency and failure to produce H2O2
T Cells
70% of total lymphocytes and have longer life span (months-years) than B cells – Helper (produce antibodies–CMI) and Cytotoxic (kill viruses)
B Cells
short lived (weeks or days), bone marrow origin, differentiate into plasma cells & produce antibodies, some can engulf bacteria and act as APC, some memory cels
How do antibodies work?
neutralize toxins, lyse bacteria in presence of complement, opsonize bacteria to facilitate phagocytosis, interfere with adherence of bacteria/viruses to cell surface.
Active Naturally acquired immunity
By suffering from an actual infection/disease
Active Artificially acquired immunity
by vaccines (including antibody production)
Passive Naturally acquired immunity
preformed antibodies from mothers milk
Passive Artifically acquired immunity
preformed antibodies (tetanus anti serum)
Consider before choosing an antibiotic?
ID organism, susceptibility, site of infection (BBB?), patient factors, safety of drug, cost of drug.
Drugs acting on cell wall?
Penicillins (+Cephalosporins, Carbapenams, Monbactams), Vancomycine, Cycloserine & Bacatracin
Penicillins
products of molds with Beta Lactum ring, inhibits synthesis of peptidoglycan and causes rupture of cell wall.
Disadvantages of penicillin? (4)
- Hypersensitive rxns 2. Narrow spectrum (Gram + only) 3. Acid hydrolysis in stomach (only pareneral admin) 4. Development of drug resistance. & hemolytic anemia
Beta lactamase resistant drugs for Staph Aureus
Methycillin (not used), Naficillin, Oxacillin & Cloxacillin
Treat pseudomonas & klebsiella
Piperacillin, Ticarcillin & Carbencillin
Natural penicillins are useful against…?
Gram +/- cocci, Gram + rods, Spirochetes
Penicillins are synergistic with…?
amino glycosides
Cephalosporins (part of Penicillins)
Beta lactum group, also acts on Gram - organisms, beta lactamase resistant, effective against e coli, klebsiella, proteus, pseudomonas
Carbapenams (part of Penicillins)
Beta lactum group, not inactivated by beta lactamase and effective against Gram - and anaerobic organisms
Monobactums (part of Penicillins)
powerful against pseudomonas (but less effective against Gram +, resistant to beta lactamase
Vancomycin
glycopeptide, inhibits cell wall synthesis, effective for Gram +, meningitis and MRSa
Cycloserine
inhibitor of TB cell wall synthesis
Bacitracin
topical; inhibits cell wall synthesis
Drugs acting on 30s
Aminoglycosides & Tetracyclines
Drugs acting on 50s
Chloramphenicol & Erythromycin
Aminoglycosides
Gentamycin & Amikacin (effective vs. Gram -, ex. E coli and proteus); Streptomycin (TB); Tobramycin (eye drops). Disadv. ototoxic and nephrotoxic and ineffective against anaerobes and do not cross bbb
Tetracyclines
Doxycycline & oxytetracycline; lyme disease, h pylori, stds, lgv, trachoma, pids. Disadv. suppresses normal flora, stains teeth in children >8yr; used during plague epidemic
Chloramphenicol
50s, broad spectrum, passes BBB, 1st line of drug for meningitis in penicillin allergic patiens, in US used for brain abcess. Toxicity: bone marrow depression and aplastic anemia
Erythromycin
50s least toxic, URI LRI Hpylori (Azythromycin & Clarithromycin), eye drops used in new borns to prevent purulent conjunctivitis (from gonococcal/chlamydial)
Inhibitors of precursor of nucleic acids?
Sulfa group (prior to GIT/GUT surgeries) & Trimethoprim
Inhibiotrs of DNA synthesis
Quinolones (Ciprofloxcin, Norfloxcin, Ofloxcin, Levofloxcine) for LRI, UTI, GIT. Toxic for growing bones (preg. women and young children)
Inhibitors of RNA synthesis
Rifampin effective vs. TB; also used in prosthetic valve endocarditis (s.epidermidis). Used to prevent meningo coccal meningitis. Causes red saliva, sweat and urine and stains contact lenses.
Drugs Act on Cell Membrane?
Polymixin; disrupts pseudomonas auroginosa (Gram -) cell membrane; topical.
Anti TB–“Other drugs”
Isoniazid (primary drug for TB), Ethambutol, Pyrazinamide
Metronidazole
bactericidal against anaerobic organisms (and protozoa like Giardia & Trichomonas); before dental extractions
Chemoprophylaxis
antibiotic treatment to prevent diseases used in 3 instances: prior to surgery, contact & immunocomprimised individuals.
Cotrimaxazole
prevent pneumocystic carini infections in AIDs patients
Clotrimazole
prevents cryptococcal meningitis in AIDs patients.
Penicillin (long acting…1-2 years) to prevent…
Rheumatic fever in patients with streptococcal pharyngitis
INH
TB
Ceftriaxone
gonococci