* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Bacteriology - Dr. Roberta Dev Anand
Survey
Document related concepts
Biochemical switches in the cell cycle wikipedia , lookup
Cellular differentiation wikipedia , lookup
Signal transduction wikipedia , lookup
Extracellular matrix wikipedia , lookup
Cell culture wikipedia , lookup
Cell encapsulation wikipedia , lookup
Cell nucleus wikipedia , lookup
Cell growth wikipedia , lookup
Organ-on-a-chip wikipedia , lookup
Cell membrane wikipedia , lookup
Type three secretion system wikipedia , lookup
Lipopolysaccharide wikipedia , lookup
Cytokinesis wikipedia , lookup
Transcript
EDUCATION “The purpose of education is to replace an empty mind with an open one.” Bacteriology 1st observed by Leeuwenhoek – 1676 with single lens microscope Definition - Bacteria Single-celled microorganisms with a variety of shapes (spheres, rods, spirals) Bacteria are prokaryotes Genetic material contained in a single circular chromosome in the cytoplasm of the cell (nucleoid) Prokaryotic Prokaryotic Fewer organelles & smaller than eukaryotes Cell wall +/ capsule Cell/ plasma membrane Nucleoid Cytoplasm Ribosomes +/-: pili, plasmids, flagellum Few have endospore Eukaryotic Cell / plasma membrane Nucleus Nucleolus Cytoplasm Mitochondria Golgi apparatus Endoplasmic reticulum Ribosomes Vacuoles Lysosomes Bacteriology Grow in various kinds of environments; extreme Without bacteria life as we know it would cease to exist! Bacteriology Bacterial cells outnumber the other cells in our bodies by 10:1! Majority are harmless or beneficial Ex: Digestive tracts of people and animals Few cause infectious disease Most common – respiratory diseases Bacteriology – Morphology Wide variety Spherical – cocci/coccus Rod – bacilli/bacillus Single cells, pairs, chains, clusters Elongated to form filaments Bacteria Gram positive cocci: Staphylococci Bacteriology – Cellular Structure Cell membrane Barrier to hold nutrients, proteins and other components of cytoplasm within cell No membrane-bound organelles – few intracellular structures No nucleus, mitochondria, chloroplasts, golgi apparatus and endoplasmic reticulum Genetic material – single circular chromosome In nucleoid in cytoplasm FEW BACTERIA HAVE ABILITY TO PRODUCE ENDOSPORES Persists in variable environment Not membrane bound Hairlike protein extensions Attach/communicate with Other cells Smaller than Eukaryotic Mobility Barrier against phagocytosis DNA outside chromosome Replicate independently Pass info via pilus Bacteriology Treat infections with antibiotics Also used for agricultural processes Industrial processes Waste treatment Cheese and yogurt production Manufacture of antibiotics and other chemicals Bacteriology – Extracellular Structures Cell wall – around cell membrane Essential to survival of many bacteria Penicillin 2 kills by inhibiting a step in synthesis of cell wall types Gram positive – thick cell wall with many layers Gram negative – thin cell wall Based on reaction to Gram stain Differences in antibiotic susceptibility Gram Staining The bacterial kingdom is subdivided into main categories by a process called Gram Staining (named after Hans Christian Gram, a Danish bacteriologist). The process is a stain that illustrates the composition of the cell wall. The gram stain consists of these steps: • Crystal violet - stains both gram negative and positive bacteria Gram's iodine - fixes the stain in gram positive bacteria Ethanol or acetone - washes the stain from gram negative bacteria Safranin - counterstain, will restain gram negative bacteria while not interfering with the previous stain in gram positive bacteria Gram stain Procedure Staphlylococcus sp. Streptococcus sp. Salmonella sp. Proteus sp. Bacteria - veterinary medicine GRAM NEGATIVE GRAM POSITIVE Cocci Staphylococcus species Streptococci Rods C: Coyrnbacterium pseudotuberculosis L: Listeria monocytogenes E: Erysipelothrix rhusiopathiae A: Arcanobacterium pyogenes R: Rhodococcus equi. Endospores: Clostridium (anaerobes) and Botulinum Anaerobes: Actinomyces bovis Acid fast: Tuberculosis Gram negative enteric rods Klebsiella Proteus: UTI E. coli: UTI Salmonella Shigella Gram negative non enteric rods Pseudomonas aeruginosa Pasteurella multocida Moraxella bovis Anaerobes: Bacteroides, fusobacterium Campylobacter: spiral twisted Rickettsia and Chlamydia Bacteriology – Extracellular Structures • Glycocalyx (a network of polysaccharides) – Surrounds the cell wall • Varies in structural complexity – – – – – – Disorganized extra-cellular polymer = slime layer Highly structured = capsule Protect from engulfment by macrophages Act as antigens Cell recognition Allows attachment to inert surfaces (teeth, rocks, etc) Bacteriology – Endospores Highly resistant, dormant structures Consist of central core of cytoplasm containing DNA and ribosomes surrounded by cortex layer Protected by impermeable and rigid coat Made by certain genera of Gram-positive rods Bacillus Clostridium Bacillus vs. Clostridium Slides can then be transported to a laboratory or stained in the field with New Methylene Blue or a Wright’s stain kit. Bacillus vs. Clostridium Bacillus anthracis, X2000. Note 2 main characteristics: 1. sharp, squared ends 2. pale capsule around bacteria Clostridium septicum, X2250. Note 3 characteristics: 1. smaller size 2. no capsule 3. rounded ends Bacteriology – Endospores No detectable metabolism Survive extreme physical and chemical stresses UV light Gamma radiation Detergents/disinfectants Heat Pressure Drying Bacteriology – Endospores Survive millions of years Survive exposures to vacuum/radiation in space Can cause disease Inhalation of Bacillus anthracis endospores Contamination of deep puncture wounds with Clostridium tetani endospores => tetanus Anthrax Tetanus Bacteriology – Pathogens Definition – bacteria or other agent that forms a parasitic association with other organisms Major cause of human and animal death and disease Examples: tetanus, food-borne illness (Salmonella, Campylobacter, leprosy, Tuberculosis (TB) Important in agriculture Johne’s disease, mastitis, salmonella, anthrax Bacteriology – Pathogens Each species has characteristic spectrum of interactions with hosts Ex: Staph/Strep => skin infections, pneumonia, meningitis, sepsis Can also be part of normal flora w/o causing any disease Bacteriology – Pathogens Some organisms always cause disease Rickettsia – gram (-) obligate intracellular parasites Ehrlichia Rickettsia rickettsii (RMSF) Chlamydia – gram (-) obligate intracellular parasite Pneumonia Urinary tract infections Opportunistic Primarily in immune suppressed hosts Bacteriology – Pathogens Treatment Antibiotics Bacteriocidal Bacteriostatic Many types – each class inhibits a process in pathogen that is different from host Bacteriology – Pathogens Prevention by using antiseptic measures Cleanse skin with antiseptic prior to needle puncture Proper care of indwelling catheters Sterilization of surgical and dental instruments Disinfectants Kill bacteria/other pathogens on surfaces Ex: bleach, Roccal, chlorhexidine Bacteriology – Growth and Reproduction Grow to fixed size Asexual reproduction – binary fission Can be rapid under optimal conditions Double every 9.8 minutes 2 identical clone daughter cells formed Can also form more complex reproductive structures that facilitate dispersal Bacteriology – Growth and Reproduction Cultured with solid or liquid media Solid – agar plates – used to isolate pure cultures of a bacterial strain Liquid Measurement of growth Large volumes needed Selective Specific media nutrients added or deficient or antibiotics added Used to ID specific organisms Bacterial Reproduction References http://www.sciencebuddies.org/science-fairprojects/project_ideas/MicroBio_Interpreting_Plates.s html http://www.vetmed.ucdavis.edu/whc/pdfs/necropsy. pdf http://www.vetmed.wisc.edu/pbs/courses/bact/labm anual/labmanual.html http://pathmicro.med.sc.edu/fox/enterobact.htm