microbiology test one

-Microbiology is the study of one celled microscopic organisms that you cannot see with the naked eye

-Bacteria, algae, fungi and viruses that can not be scene with the naked eye.

dna organized in a single chromosome. No nucleus. No mitosis

Sna organized in multiple chromosomes inside a nucleus. Mitotic division.

• protozoa
• fungi
• slime molds
• algae

These microscopic organisms are divided into two groups based on cell structure

• Eukaryotes (also spelled eucaryotes) –"eu" = true, + "caryos" = nucleus
• –Protista

Prokaryotes (also spelled procaryotes) –"pro" = before, + ”caryos" = nucleus –Lower Protista –bacteria

• Endoplasmic Reticulum:System of large sacs and smaller tubes responsible for macromolecular p transport
• –Smooth ER: W/O ribosomes, involved with lipid and steroid synthesis.
• –Rough ER: W ribosomes, involved in protein synthesis

Cell membrane: Complex lipoprotein structure

Cell wall: Rigid/ Mod rigid polysaccaride structure

Mitochondria:Production of ATP and aerobic metabolism, animal cells.

Chloroplasts:Contain pigments and enzymes used in photosynthesis

Well-defined surrounded by nuclear membrane

Control center for growth and development

Contains chromosomes, rna, nuclear membrane continuous with er

Ribosomes: Responsible for protein synthesis

Lysosomes: Responsible metabolism of ingested organic material

Plasmid: Circular DNA form chromosome that may confer antibiotic resistance (bacteria’s ability to produce toxins)

Mesosomes:

Cilia: –Move in coordinated waves –Numerous on cell exterior

Flagella: –Singular or present in small numbers –Move in undulating motion –Longer than cilia

Eucaryotic

Eucaryotic

• More advanced
• Reproduce by mitosis
• Have a nucleus and cell membrane
• Contain membrane bound large organelles (mitochondria, lysosomes, ribosomes, etc.)
• sizes - 5 micrometers to 100 micrometers

• Blue green algae
• bacteria
• rickettsiae
• mycoplasma

Eucaryotic

• Capsule or Slime Layer –Outer most layer surrounding the outside of cell produced by the cell itself –common in pathogenicorganisms pathogenic organisms
• If clearly detectable called a capsule, if not called a SLIME LAYER
• Contributes to a organisms to cause disease by inhibiting the ability of host phagocytosis cells to engulf the organism. (may or may not)

• "pro" = before, + "karyos" = nucleus
• Nucleoid region with one long circular DNA
• Simple architecture not understood until EM technology in 1940's
• Typical sizes: 1 u m diameter = 1 micron = 10^-3 mm

• Varies widely to density, thickness and chemical composition
• Prevents virus attachment
• Functions as external nutrient storage
• Prevents phagocytosis
• In pnemococcal organism the capsule is antigenic, induces the synthesis of specific antibodies, which can be used for identification in the lab

• Not all bacteria have them
• A layer outside the cell wall ahydrophilicgel of polysaccharides –a hydrophilic gel of polysaccharides
• Total layer = capsule
• Partial enclosure = slime layer

• Help protect the bacteria
• –impede digestion by leukocytes
• –Capsulesaidincolonization Capsules aid in colonization
• assist the cell to attach to surfaces

• Cell wall: Mod rigid to very rigid
• –Protects cell from bursting
• –Maintain cell shape, essential to survival
• Cell wall in gram-positive bacteria
• –High lipid count, stainspurple/blue/violet in gram stain stain
• –Murein network: Peptide chains attached to larger polysaccharide chains
• Cell wall in a gram-negative bacteria, complex –stains pink/red
• CW
• –Inner space –Periplasmic space
• –Middle layer –-thin peptidoglycan strong
• –Outer layer – Lipopolysaccaride LPS

a. Gram-positive bacteria have simple, thick cell walls. Their cell walls are composed of a relatively large amount of peptidoglycan.

b. Gram-negative bacteria have less peptidoglycan and are more complex. They have a peptidoglycan layer surrounded by the plasma membrane and an outer membrane.

-Gram-negative bacteria are typically more resistant to host immune defenses and antibiotics.

• Gram-Positive Bacteria
• -Broad, diverse group
• -Antibiotic producing bacteria are in this group -Example shown is Streptomyces (streptomycin) -And (next slide)

Gram positive bacteria

Mycoplasma shown covering a human cell; some species of mycoplasmas cause walking pneumonia

Outer layer is Lipopolysaccaride

LPS is responsible for severe symptoms gram-negative infection such as vascular collapse, hemorrhage, shock, and leukopenia.

Because of these effects LPS is often known as endotoxin.

Cell Wall –Mycoplasma is the only bacteria that does not have a cell wall.

For this reason mycoplasma is sensitive to environment and must require special conditions for growth in the laboratory.

Cell wall provides an ideal selective target for antibiotics. Inhibit cell wall synthesis. Membrane ruptures -dies

• ER is absent
• Mitochondria are absent
• Chloropolasts and lysosomes are absent
• Mesosomes –Found in cell membrane and allow for attachment of DNA in cell division (found mostly in gram positive bacteria)

Nucleus

No distinct nucleus

• Cell may contain one or more regions of nuclear material called nucleoids
• No mitosis apparatus
• Chromosomes exist freely in cytoplasma – may be circular or attach to cell membrane

• 80% water
• Proteins, lipids, carbohydrates, nucleic acids electrolytesandenzymes acids, electrolytes and enzymes.
• Ribosomes –slightly smaller than eucaryotic Concentration of molecules is very high – this results in a high osmotic pressure

REPRODUCE BY BINARY FISSION

Prokaryotes grow and adapt rapidly-The doubling time for E. coliis 20 minutes. Start with one E. colicell. After 48 hours of doubling every 20 minutes, the mass of E. coliwould be 10,000 times the mass of the earth.

• Bacteria do not have gene transfer by sexual reproduction, but do transfer genes. Why? This is an aid in adapting (evolving). 1. Three (3) ways for genes to be transferred between cells:
• a. Transformation–cell takes up genes from the surrounding environment.
• b. Conjugation–direct transfer of genes from one prokaryote to another. Use the sex pilus to conjugate.
• c. Transduction–viruses transfer genes between prokaryotes.

• Many prokaryotes are motile
• -Some exceed speeds 100 times their body length per second.
• Modes of movement –Note the three types:
• a. Flagellum-basal apparatus rotates the flagellum and propels the cell
• b. Corkscrew movement of spirochetes (helical)
• c. Some prokaryotes glide over jets of slimy secretions.

Many prokaryotes move toward or away from a stimulus = taxis. Chemotaxisis the movement toward or away from a chemical.

• Aerobic Bacillus, Clostridium, Sporosarcina
• Intermediate form of the organism that develops in response to adverse environmental conditions environmental conditions
• Regenerate to a vegetative cell when conditions improve.
• Resist dryness, heat and poor nutrition
• Function as a protective coat around nucleic material

• Note: surprising answer: we are not used to realities we cannot see.
• ubiquitous and prolific
• most common in soils, esp. where any potential food.
• Also in water and air

• Disease. –Since discovery of infectious microbes, much time effort and resources spent fighting and preventinginfectiousdiseases preventing infectious diseases . controlled by sanitation, preventive medicine,
• Agriculture. –microbes vital in processing materials in soil, e.g. nitrogen, sulfur, etc.

Only inside tissues of organisms, kept at bay by defensive mechanisms.

Even so, challenges common (cut finger, get infected).

• Microbial "behavior" is very simple:
• EAT, GROW, AND DIVIDE.
• Growth rates can be phenomenally
• fast:
• –e.g. some bacteria can reproduce double every 20 min. under optimal conditions.

• Microbial fermentation responsible for
• –alcoholic beverages, breads, pickles, cheeses, etc.
• –Control of food and drink spoilage is major concern of food industry.

Microbes have incredible variety of metabolic tricks; – used to produce acetone and other commercial solvents, pharmaceuticals, antibiotics, preservatives, etc.

• Genetic engineering
• Ability to move genes freely from one organism to another
• Select genes of interest and amplify their expression.
• Bacteria are natural hosts for such activities.

• Mycoplasma 0.4 um
• Haemophilus influenza 1.2 um
• Staphylococcus aureus 0.9 um
• E coli 1.5 um
• Bacillus Megaterium 4 um
• red blood cell um

• SHAPE under microscope
• FIVE BASIC SHAPES
• • COCCI -spherical shape
• • BACILLI -rod shaped
• • VIBRIOS -comma
• • SPIRILLUM –spiral
• • FUSIFORM -spindle

• GRAM POSITIVE
• SECRETES EXOTOXINS
• SPORE FORMER
• Causes skin infections
• Septicemia
• Meningitis
• Pneumonia

• Rod shaped, pairs
• Gram positive
• Anaerobe
• Spore Former
• Secretes exotoxins It causes a toxic food poisoning knows a botulism

• FOUND IN SOIL
• FECES
• POORLY CANNED OR PRESERVED FOODS

Ingestion or puncure wounds

• TOXINS ARE INGESTED FROM CONTAMINATED FOOD
• ◦ canned foods vegetables, fish, fruits

• SYMPTOMS ARE ABRUPT 18 TO 36 HOURS AFTER INGESTION
• ◦ Nausea , vomiting , abdominal cramps, diarrhea

• Frequently precede neurologic symptoms
• DESCENDING WEAKNESSAND PARALYSIS

• Produces tetanus
• Rod shapped in pairs
• Spore formiing
• DESCENDING WEAKNESS AND PARALYSIS

• Gram positive
• cocci
• in pairs diplo and chains
• may produce capsules
• aerobic bacteria
• commonly found in the nasopharynx

• Touch
• Airborne route

The leading cause of Community acquired pneumonia

• BEGINS WITH SORE THROAT, LARYNGITIS
• TRACHEOBRONCHITIS SPREADS DOWN WARDVIABRONCHI LOBAR WARD VIA BRONCHI -LOBAR
• ALVEOLAR INVOLVEMENT
• CONSOLIDATION
• possible pleural effusion

• Gram pos cocci
• seen in grape like clusters
• aerobic
• Facultative anaerobe
• Cuases pneumonia, empyema and wound infections

Found as normal flora on skin

• touch
• contact with contaminated articles

• Causes pimples, boils, wound infections
• pneumonia

• A GRAM NEGATIVE ROD
• AN OPPORTUNIST
• Cause 10% HAP infections

• water loving
• contaminates respiratory equipment
• pulmonary infections
• bronchitis and pnewmonia
• smelly green sputum

Soil, water, skin, gi tract

• poor hand washing
• direct contact with contaminated equipment

• Hospital population
• RESPONSIBLE FOR NOSOCOMIAL INFECTIONS
• AN OPPORTUNIST WEAKENED HOST

• Gram neg rod
• aerobic
• water loving, infect rt equipment

widely distrubution in nature

• poor handwashing
• direct contact with contamintated equipment

• hospital population
• responsible for nosocomial infections
• an opportunist weakened host

• Gram negative rod
• facultative anaerobie
• responsible for 45% of all HA infections

feces

poor handwashing

• necroritizing
• pneumonia
• wounds
• uti
• septicemia

• gram negative rod
• normal flora in upper respiratory tract
• most common cause of epiglottis in children
• also causes croup

• Gram negative bacillus
• responsible for whooping cough
• Transmitted by contact with respiratory tract secretions

• Acid fast, gram + bacillus rods
• aerobic

• airborne
• droplet nucleus

• smallest bacteria
• gram negative
• three later membrane
• no cell wall
• most common type of atypical pneumonia

• spores
• direct skin penetration
• athletes foot

• they form spores, and release them into the air
• they are very tiny and stay in the air for a long time
• man gets infected by inhaling the fungal spores into the lungs
• some spores are normal flora

• Caused by fungi hostoplasma capsulatum
• found in most countries
• ENDEMIC IN OHIO AND MISSISSIPPI VALLEYS
• 50% OF THE PEOPLE IN THESE REGIONS TEST POSITIVE FOR SKIN TEST
• EFFECTS MOSTLY INFANTS AND ELDERLY

Blastomycosis– –Mild self limiting disease

Respiratory infection may cause pneumonia, pleural effusion and lymph node enlargement.

Coccidiomycosis – –Three types Three types One mild, one multi -system and one system and one progressive pulmonary

• soil contaminated by droppings of chickens birds and bats
• inhalation of spores
• results in lesions in the lungs hilar nodules
• granulomas, caseation, necrosis

• can disseminate into other body tissues as well
• causes multi organ disorders including meningitis

amphotericin b

• is horman in humans
• found in upper respiratory tract
• gastrotesitnal

• pneumocystis carinii
• yeast like fungus that is protozoan
• rarely problematic - in most it lies dormant
• aids or immunocompromised host
• clinically - abrupt fever, tachypnea, hypoxia, and cyanosis
• cause alveolar wall thickness
• Treatment - pentamidine

• When patient is immunosupressed
• Excessive antibiotic therapy
• steroid therapy
• aerosolised steroids