Microbiology Bacteria

  1. Nosocomial Infections
    Infections acquired through the hospital
  2. Zoonoses
    Animal diseases that spread to humans
  3. Capsule
    Polsaccharide coat protecting against phagocytosis
  4. Fimbriae
    • -Hairs similar to cilia
    • -also called "common pili"
    • -function: cell adhesion
  5. Toxins
    endo: remain within cell until it is lysed by host

    exo: secreted from cell into host
  6. Factors in Host Resistance
    • -1st line of defense: mechanical/chemical aspects
    • keratinized , dead skin has poor nutrients
    • sweat, eye with lysozyme, upper resp tract, stomach ph labile/pepsin

    -2nd line of defense: inflammation and phagocytosis (WBC mediated)

    -3rd line: antibodie -->plasma cells and memory-->immunoglobulins
  7. F-pilus
    Sexual conjugation ONLY in Gram Negative bacteria
  8. Capsule functions
    • Food Reserve
    • Prevent dehydration(osmosis prevention)
    • Prevent phagocytosis
    • Emits a foul odor which repels protozoa
  9. Slime Layer (Glycocalyx)
    Polsaccharide coating secreted by many bacteria. Covers surface like a film and allows bacteria to adhere firmly to various structures, e.g. skin, heart valves, catheters.

    Adheres bacteria to surface of teeth-->dental plaque
  10. Cytoplasmic membrane
    • Composed of phospholipids and proteins
    • Gram + may contain mesosomes(fnc unknown)
  11. Cytosol (cytoplasm)
    • 75% water / 25% solutes
    • Water w/in acts as a catalyst for chemical rxn's.
    • Food suspended in water
    • Resovoir for waste product formation
    • Many major enzymes reside here (glycolysis)
  12. Nucleoid
    • No nuclear membrane
    • circular DNA ball of string
    • haploid
    • no histones for gene regulation
  13. Ribosomes (polysomes)
    • Function: translation of proteins
    • 70 S
  14. Plasmids
    • "extrachromosomal DNA"
    • F+ males
    • fimbriae
    • col factors (chemicals which kill other microorganisms
    • R-factors (chemicals which destroy col factors)
    • Nitrogen fixation
  15. Plasmids (cont'd)
    • double stranded, circular DNA that are capable of replicating independently of the bacterial chromosome.
    • -Transmissable plasmids: can be transferred from cell to cell conjugation, contain about 1-3 copies per cell
    • -non transmissable: 10-60 copies per cell
  16. Transposons
    • Jumping genes
    • -can code for drug resistance enzymes, toxins, and variety of metabolic enzymes, and can either cause mutation in the gene in which they insert or alter the expression of nearby genes.
    • -not capable of independent replication
  17. Endospores
    • -round rigid structure within the cell with a duplicate copy of the chromosome
    • - coat of enamel like substance(dipicolinic acid and Ca++)
    • - enhances survival in unfavorable environment
    • -must autoclave: boiling water will not destroy
    • -stain with malachite green (Ca++ chelator)
    • -Many non pathogens have endospore e.g. Sporosarcina
    • -only pathogens in Bacillus and Clostridium
  18. Cell Wall
    • fncs:
    • structural support, barrier, shape maintenance
    • -If cell wall removed, cell becomes spheroplast
    • -protoplast: similar to above, but never had cell wall
    • -both of the above can only survive in isotonic solutions
    • -exceptions: mycoplasma and ureaplasma
  19. Gram Positive + Bacteria
    • CW is thick(20-80 nm) and is 60-80% peptidoglycan
    • -Gm+ possess NAG and NAM
    • -teichoic acid that are linked to muramic acid
    • -teichoic acid may also contain ribitol or glycerol which are linked by hydroxyl groups to sugars or amino acids.
    • -not much protein in CW of gram positive
  20. Gram + (con't)
    • NAM contains alternating D- and L- amino acids
    • penicillin breaks these D and L linkage
    • -cell walls possess small amounts of lipids, therefore they stain VIOLET
  21. Gram negative (-)
    • -CW is more complex, less peptidoglycan (10-20%)
    • -Possess another "outer" layer ontop of peptido layer composed of proteins, phospholipids, and lipopolysacrid
    • -Lipopoly is toxic to animals and is termed Endotoxin. responsible for fever and shock
    • -CW not easily penetrated by detergents because of lipid in CW --> Stains RED!
  22. Inclusions
    • Small globules of stored food
    • some are inorganic/organic
  23. Chromatophores
    • Photosynthetic membranes that contain chlorophyll
    • not found in pathogens
    • 02 is not photosynthetic product in many bacteria
  24. Bacterial Nutrition
    • Carbon: Autotroph, Hetertroph
    • Nitrogen
    • Inorganic ions: P, S, K, Ca, Fe, etc.
    • Water
    • Energy: phototroph, chemotroph
    • Oxygen if an aerobe
  25. Halophiles
    Salt loving organisms
  26. Physical condition for growth
    • pH: buffers
    • Temp: Psychrophiles: 0-20 C
    • Mesophiles: 20-40 C
    • Thermophiles: above 45 C
  27. Bacterial Reproduction
    Binary Fission

    • Generation time: b= B x 2^n
    • bacterial growth curve
  28. Bacterial Energy Mech's
    • Photosynthesis
    • Glycolysis
    • Fermentation
    • CAC
    • Chemoautotrophic
  29. Amount of genetic material that can code for typical bacterium and human
    • 2000 proteins for bacteria--> bacteria are haploid
    • 100,000 for humans
  30. Replica Plating
    Identifies MUTANTS
  31. Ames Test
  32. Transformation
    Competence: the ability of a microorganism to take up DNA from its environment. Some bacteria secrete a competence factor.
  33. Transduction
    • Bacteriophage (virus)
    • Lysogenic life cycle
  34. Gram +
    • No F-pilus.
    • Form Conjugation Bridges
    • Recipient secretes pheromones
    • Donor secretes Adhesin(protein) and the recipient possesses receptors on its CM
  35. Genetic Engineering
    • Manipulation of genetic material. This includes altering the DNA of an organism to suppress or enhance the activities of its own genes and combining genetic material of different species.
    • - Restriction enzymes and DNA Ligases are key tools in forming recombinant DNA molecules.
    • -Plasmids and Lambda Phage are choice vectors for DNA cloning in bacteria.
  36. Mode of transportation for Recombinant DNA molecules
    • 1) Foreign DNA molecules can be precipitated by Ca++ phospate are taken up by the animal cells
    • 2) DNA is MICROINJECTED into cells
    • 3) Viruses can be used to bring new genes into animal cells. The most effective are retroviruses.
  37. Simple stain with BASIC dye
    • Prepare smear
    • air dry
    • heat fix
    • add crystal violet or methylene blue or safranin for 60 sec
    • wash the slide well with water (top and bottom)
    • blot the slide dry
    • observe under low, high-dry and oil-immersion lenses
  38. Simple stain with an ACID dye
    • -Place several drops of a bacterial liquid culture at end of slide
    • -add drop of Nigrosin(India ink) to bacteria on slide
    • -using a loop, mix bacteria and Nigrosin
    • -using second slide, spread the wet mixture of bacteria and nigrosin across first slide
    • -air dry
    • -observe under low, high-dry, and oil-immerison lense
    • -**Bacteria appear white and background black-purple
  39. Gram Stain
    • -Prepare smear
    • -air dry
    • -heat fix
    • -add crystal violet for 30 sec
    • -wash well with water (top and bottom of slide)
    • -Add gram's iodine for 30 sec
    • -wash slide well with water (top and bottom)
    • -tilt slide over the sink and decolorize with 95% alcohol (decolorizer) until no further purple color flows from slide
    • -wash slide well with water
    • -add safranin (counter-stain) for 15 sec
    • -wash well with water
    • -blot dry
    • -obs under microscope-->low, high-dry
    • -Gram + stain purple
    • -Gram - stain RED
  40. Endospore Stain
    • -Prepare smear
    • -air dry
    • -Heat fix
    • -Place old newspaper over your immediate work area to facilitate clean-up
    • -place small piece of paper towel over the smear on the slide
    • -hold the slide and small piece of paper towel with a clothes pin
    • -add malachite green to saturation to the piece of paper towel over the smear.
    • -steam the slide over a flame for 5 min. add more malachite green as evaporation occurs
    • -allow the slide to sit at room temp until cool (5 min)
    • -remove piece of paper towel
    • -wash slide well with water
    • -counter stain with safranin at room temp for 30 sec DO NOT STEAM
    • -wash slide well with water
    • -blot dry and observe under scope
    • **Endospores stain GREEN. Vegetative cells are RED.
  41. Acid-Fast Stain
    • -Prepare smear
    • -Air dry
    • -heat fix
    • -place old newspaper or disposable paper over your immediate work area to faciltate clean up
    • -place small piece of paper towel over the smear
    • -hold the slide with paper towel with a clothes pin
    • -add carbol fuschin to saturation to the piece of paper over the smear
    • -steam the smear for 5 min. add more carbol fuchsin to the piece of paper over the smear as evap occurs
    • -allow the slide to sit at room temp until cool (about 5 min)
    • -remove the piece of paper towel
    • -wash slide well with water
    • -tilt the slide over the sink and decolorize with ACID ALCOHOL until no further red color flows form the slide.
    • -wash slide well
    • -counter stain with methylene blue at room temp for 30 sec. DO NOT STEAM!!
    • -wash slide well
    • -blot dry
    • -observe under scope
    • **Acid fast bacteria stain RED
    • Non acid fast bacteria stain BLUE
  42. Detection for Flagella
    • -wet mount
    • -hanging drop
    • -stain
    • -EM
    • -Motility agar
    • -test for enzymes
  43. Methods to obtain pure cultures from mixed cultures
    • Streak Plate
    • Pour Plate
  44. Mycoplasmae ( and Ureaplasma)
    • -smallest cells (0.12-0.25 nm)
    • -Pleomorphic. gram negative (stain poorly)
    • -sterols in cytoplasmic membrane
    • -grown on artificial media containing cholesterol
    • PPLO (pleura pneumonia like organism)
    • -cause: pneumonia, found in joints of patients with arthritis, urinary tract infections
  45. Mycoplasma Pneumoniae
    • -Mycoplasmae are the smallest free living organisms
    • -no cell wall and stain poorly with gram reagents
    • -pleomorphic
    • -CM contains cholesterol , grow slowly in lab
    • -pathogenic only for humans and is transmitted via resp droplets.
    • -only one serotype
    • -immunity is incomplete
    • -accounts for 5-10% of all community-acquired pneumonia
  46. Clinical findings of Myco pneu
    • -most common type of "atypical" pneumonia
    • -onset is gradual, usually beginning with a cough , sore throat, ear-ache, some whitish, non-bloody exudate is produced. This usually resolves spontaneously in 10-14 days.
  47. Laboratory diagnosis of Myco Pneu
    • -Usually not made by culturing of sputum becuz it takes at least a week for colonies to appear on special media
    • -serologic testing usually done
  48. Treatment for Myco Pneu
    • -erythromycin and tertracycline
    • -penicillins and cephalosporings are not used becuz the organism has no CW.
  49. Mycoplasma Hominis
    • -cause of pelvic inflammaotry diesease
    • -others are implicated in arthritis
  50. Ureaplasma
    • -similar to mycoplasma, except is UREASE positive.
    • -Urease degrades urea to ammonia and co2.
  51. Ureaplasma Urealyticum
    -may cause approx. 20% of cases of non-gonococcal urethritis. Sexually transmitted.
  52. Bdellovibrio
    • -small monotrichous gram-negative rods (.3 um)
    • -parasite of other bacteria. Not a human pathogen
    • -enters host cell wall
    • -resides b/w CW and CM of host
    • -elongates and then fragments with lysis of host bacterium
  53. Gliding Bacteria
    -secrete slime tracks upon which they move
  54. Actinomycetes
    • -Gram positive bacteria
    • -long, branching chains of rods
    • -superficially look like hyphae of molds
    • -procaryotic cells with procaryotic chemicals
    • -some are aerobic; some are anaerobic
    • -Two genera: Actinomyces & Nocardia
  55. Actinomyces Israelii
    • -Anaerobe. normal flora of the oral cavity. after local trauma, may invade tissues. endogenous infection
    • ** sulfur granules
    • -in about 50% cases the initial lesion involves the face or neck; in the rest, the chest or abdomen is the site. pelvic actinomycosis can occur in women.
  56. Actinomyces Israelii (lab diagnosis)
    • -gram stain, anaerobic growth, immunofluorescence of sulfur granules.
    • -no good serological tests or vaccine.
    • -treatment consists of prolonged adminstration of antibiotics like penicillin G
    • -Lumpy Jaw
  57. Nocardia asteroides (some stains are acid-fast) or Nocardia Brasiliensis
    • -aerobes and found in the environment (soil)
    • -exogenous infection. inhale or traumatic inoculation
  58. Nocarida asteroides ( Clinical findings)
    • -Disease usually begins as a pulmonary infection and may progress to form abscesses and sinus tracts.
    • -sulfur granules are not formed
    • -in immunocompromised persons, the organism may spread to the brain, skin, or kidneys
    • -disease is non-communicable
  59. Nocardia species (lab diagnosis)
    • -gram stain, aerobic growth,
    • -no vaccine
    • -no prophylactic drug
    • -treatment: trimethoprim-sulfamethoxazole
  60. Mycobacterium
    • -Wax in the CW. most abundant wax is mycolic acid
    • -rod shaped
    • -waxy barrier greatly reduces permeability to many molecules like gram stain.
    • -waxy coat makes these organisms resistant to drying and to many chemicals.
    • -this helps them survive inside of a body of a susceptible patient.
    • -usually resistant to killing by phagocytes
    • -their resistance to drying also facilitates airborne transmission.
    • -their waxy coat does not protect them form heat and they are killed by pasteurization.
  61. Mycobacterium (cont'd)
    • -all species are acid-fast stain becuz of high lipid (wax) in CW
    • -only other bacteria which could be acid-fast are some strains of nocardia asteroides
    • -rod shaped and usually seen in clumps becuz of the viscosity of wax
    • -stain poorly with gram dyes
  62. Mycobacterium Tuberculosis
    • -grows slowly (generation time of about 18 hours) as is an obligative aerobe.
    • -media used for its growth (lowenstein-jensen) contain complex nutrients (egg yolks) and dyes (malachite green). -transmitted mainly person to person by resp aerosol, focus of infection is lungs
    • -in body it resides mainly within RE cells.
  63. Mycobacterium tuberculosis (cont'd)
    • -humans are natural resovoir; there's no animal resovoir
    • -in developing countries, M. bovis (form unpasteruized cows' milk) can cause TB.
    • - does NOT produce exo/endotoxins
    • -survives and multiplies within phagosomes.
    • -produces a protein that prevents phagosomes form fusing with lysosomes. allowing it to escape digestive enzymes
    • -lesions are dependent on the presence of the organism and the host response.
    • -Ghon complex
  64. Mycobacterium Leprae (Hansen's diesease)
    • -can only be grown in lab on footpads of mice/armadillos
    • -humans are natural hosts and perhaps mice/armadillos are resovoir hosts
    • -optimal temp for growth is 30 C ; therefore prefers to grow on skin and superficial nerves.
    • - grows very slowly with generation time of about 14 days; therefore antibiotic therapy must be cont'd for years.
  65. Mycobacterium Leprae (cont'd)
    • -infection acquired by prolonged contact with patients with lepromatous leprosy who discharge large numbers of the bacteria in nasal secretions and skin lesions.
    • -most cases in asia and africa
    • -replicates intra-cellularly, typically within skin histiocytes, endothelial cells and Schwann cells of nerves.
    • -two forms: Tuberculoid, which is the cell-mediated iummune response to the organism limits its growth, and a very few acid-fast bacilli are seen.
    • -hypo-pigmented macular skin lesions, thickening of superficial nerves, and anesthesia are seen
    • -Lepromatous leprosy: multiple nodular skin lesions occur, resulting in typical leonine(lion like) face.
  66. Chlamydiae
    • -all gram negative coccobacilli
    • -all are very small (.3 um)
    • -all obligate intracellular parasites (must have living host)
    • -enzyme dificent "energy parasites"
    • -no binary fission (endocytosis and multiply similar to some protozoa)
  67. Life cycle of Chlamydia
    • 1. Attachment to host cell
    • 2. entry by phagocytosis
    • 3. conversion to reticulate bodies
    • 4. reproduction of reticulate bodies
    • 5. condensation of reticulate bodies to form elementary bodies
    • 6. release of elementary bodies
  68. Chlamydiae (important properties)
    • -obligative intracellular microorganisms
    • -have rigid cell wall but do not have a typical peptidoglycan layer.
    • -their walls resemble those of gram-negative bacteria, but lack muramic acid.
    • -all chlamydiae share a group specific lipopolysaccharide antigen. They also possess speices-specific and immunotype-specific antigens (proteins)
  69. Psittacosis (aka ornithosis, bird fever)
    • -etiological agent: Chlamydia Psittaci
    • -vector: birds
  70. Walking Pneumonia
    • -etiological agent: Chlamydia Pneumoniae
    • -droplet transmission, common nosocomial infection
    • one can function, but feel poorly
  71. Trachoma ( chronic conjunctivitis)
    • -etiological agent: C. trachomatis (strains A, B, C)
    • -contact or fomite transmission
  72. Non-Gonococcal Urethritis
    • -etiological agent: C. Trachomatis (strains D--->K)
    • -sexual contact
    • female may be unaware, and may lead to sterility
    • male is aware due to exudate and painful urination
    • most common sexually transmitted disease
  73. Inclusion Conjunctivitis
    • -etiological agent: C. Trachomatis (strains D-->K)
    • -occurs primarily in newborn (from mother with NGU)
    • -copious fluid, itching
  74. LGV (Lymphogranuloma Venerum)
    • -etiological agent: C. Trachomatis (strains L1, L2, L3)
    • -pinpoint blisters which migrate to lymph nodes becoming buboes (enlarged lymph nodes)
  75. Rickettsiae
    • -all gram negative coccobacilli
    • -all are very small (0.3 um)
    • -all obligate intracellular parasites
    • -enzyme deficient
    • -binary fission, usually have arthropod vectors(mite or flea), longer generation time (hours vs. minutes.
    • the highlighted above is main differences from chlamydia.
  76. Rickettsiae (pathogenesis)
    • -They typical lesion caused by Ricks is a vasculitis, which is inflammation of blood or lymph vessel, in the endothelial lining of the vessel wall where the orgainsm is found.
    • -damage to vessel leads to characteristic rash and in edema and hemmorhage caused by increased capillary permeability.
    • -endotoxins may be invovled, but def. not exotoxins or cytolytic enzymes
  77. Rocky Mountain Spotted Fever
    • -etiological agent: Rickettisia Rickettsii
    • -vector: tick
    • 1. resovoir host: rabbitt
    • 2. Human
    • 3. Diseases of mother tick
    • - acute onset of non-specific symptoms: fever, severe headache, myalgias and prostation. typical rash, which appears 2-6 days later, begins with macules that frequently progresses to petechiae.
    • -rash usually appears on hands and feet then moves to trunk.
  78. RMSF (cont'd)
    • -profoudn CNS changes such as delirium and coma can occur.
    • -disseminated intravascular coagulation, edema and circulatory collapse may ensue in severe cases.
  79. Rickettsial Pox
    • -etiological agent: Rickettsia Akari
    • -vector: Mite (arachnid)
    • -resovoir host: mouse or rat
    • -symptoms: fever, eshcar-burning type of lesion, which becomes locally necrotic, papulovesicular rash(milder than RMSF)
  80. Epidemic Typhus (not typhoid fever)
    • -etiological agent: Rickettsia Prowazekii
    • -vector: louse
    • -resovoir host: non specific animal
    • -as louse bites, a reflex occurs causing it to defecate and or vomit...scratching bitten area causes infection
    • lesion usually occurs on chest, areas of warmth
  81. Scrub Typhus (fever)
    • -etiological agent: Rickettisa Tsutsugamushi (dangerous bug)
    • -vector: mite
    • -resovoir host: mouse/rat
    • -fever, eshcar lesion, hepatomegaly/splenomegaly
    • more prevalent in tropical areas
  82. Endemic Tyhpus Fever (murine typhus)
    • -etiological agent: Rickettsia Typhi
    • -vector: flea
    • -resovoir host: mouse/rat
    • -fever, malaise, eschar
  83. Trench Fever
    • -etiological agent: Bartonella Quintana
    • -vector: louse ( from poor sanitation)
    • -resovoir host: non-specific animal
    • -characteristic rash called "roseolar"
  84. Q Fever
    • -etiological agent: Coxiella Burnetti
    • -vector: tick
    • -resovoir host: cow ( today by dried feces)
    • - main organ affected is LUNGS; pneumona may ensue
  85. Human Monocytic Ehrlichiosis
    • -etiological agent: Ehrlichia Chaffeensis
    • -vector: tick
    • -resovoir host: dog
    • -preferentially prefers WBCs
  86. Bartonella Henselae
    • -cause of bacillary angiomatosis(many tumors in vessels)
    • -mainly occurs in AIDs patients
    • -vector: cat
    • -treatment: doxycycline
    • -immunocompetent ppl: causes cat-scratch fever which is localized lymphadenopathy
  87. Bartonella Bacilliformis
    -causes two rare diseases: Oroya Fever and Verruga Peruana, both of which are stages of Carrion's Disease and has sandfly vectors.
  88. Weil-Felix Test
    • detects anti-rickettsial antibodies in a patient's serum by agglutination of the Proteus organsim, is based on this cross rxn.
    • -Test is not good for Q fever
    • -False positive test if patient has urinary tract infection caused by Proteus species.
Card Set
Microbiology Bacteria
Microbiology Bacteria Flashcards