Bacteria Classifications Flashcards
Cellular vs acellular
-Cellular has genetic info; replicates autonomously
E.g. Prokaryotes, Eukaryotes
-Acellular is able to do one/both
E.g. Viruses, prions
Eukaryotes vs Prokaryotes - num of cells
Eukaryotes - multicellular
E.g. fungi, protozoa, helminths
Prokaryotes - unicellular
E.g. bacteria
Gram stain purpose
Differentiate between gram +ve and gram -ve bacteria
Similarities in gram +ve and gram -ve (cell envelope)
- Contain innermost phospholipid bilayer
- Have cell wall
Differences in gram +ve and gram -ve (cell envelope)
- Cell wall thicker in gram +ve than gram -ve
- Extra layer of phospholipids above cell wall in gram -ve
- Gap (periplasm) between inner phospholipid bilayer and cell wall in gram -ve
Gram stain process
- Add crystal violet dye
- Add iodine dye
- Alcohol water wash
- Safranin as counterstain for red colour
Alcohol water wash effect on gram +ve and gram -ve bacteria
In gram +ve the dyes are retained but for gram -ve they are washed away
Periplasm can store beta lactamase (T/F)
True
Cell wall - bacteria - made up of
- Peptidoglycans – sugar backbone NAN, NAG
- Peptide side chains on sugar backbone
Gram -ve cell wall components
Porins - tubular; connects outside environment to periplasm
Murein lipoproteins - connects cell wall to outer membrane
LPS - Lipopolysaccharide - O lipids, core polysaccharide, Lipid A/endotoxin (embedded in outer membrane)
Endotoxins - present gram -ve’s, only present in one gram +ve — Listeria
Antibiotics do not travel through porins (T/F)
False
Porins can change to avoid antibiotics travelling through porins (T/F)
True
Gram +ve cell wall components
Lipotechoic acids- embedded in cell wall; regulates enzymes; can cause immune response
Gram +ve and -ve cell wall similarities
- Flagella – tail like; attached to a basal body for anchoring
- Pili/fimbriae – attach one bacteria to another/mucosal human structures (grappling hook)
Host immune response to bacteria
Bacteria are slippery - need something to stick out like pins
Antibodies and C3B (complement cascade) attached to bacteria – makes it easier for host immune system to destroy cells
-> They act as opsonins
Opsonin function
-allows macrophages to attach and consume cells
Bacteria possessing capsules
SHiN SkiS Streptococcus pneumoniae, Haemophilus influenza type B, Neisseria meningitidis, Salmonella, Klebseilla pneumoniae, group B strep.
Bacterial genome
- Bacterial chromosome – contains essential bacterial genes
- Plasmids - transfer factors to other bacteria
- Antibiotic resistance
- Toxins
- Code for virulence factors – pili, flagella
Bacteria transferring genes via transformation
These can all cause meningitis and has IgA-ase - degrades IgA
S pneumoniae
H influenza type B
Neisseria
IgA function
Prevents adherence of bacteria to surfaces
Conjugation process
F+ cell has the plasmid
F- lacks the conjugation gene
Hfr cell - chromosome is incorporated
Transposition process
Via Transposons - jumping genes
Can move from:
plasmid -> plasmid
plasmid -> chromosome
Transduction process
Via bacteriophages
Generalized transduction
Specialized transduction
- can transfer genes for antibiotic resistance to bacteria
Bacteria classified by cell wall properties
Wall absent
Thin, flexible walls present
Strong cell wall present (not necessarily thick wall, just inflexible)
Wall less cell classifications
Mycoplasma - causing pneumonia
Flexible, thin wall classifications
Spirochetes
- Treponema – Syphilis
- Borelia – Lyme disease
- Leptospira – Leptospirosis
Rigid cell wall classifications
Non free living (obligate, intracellular) Free living (extracellular)
Non free living (obligate, intracellular) classifications
Rickettsia (RMSF, Typhus, Q fever)
Chlamydia (urethritis, trachoma, psittacosis)
Free living classifications
Gram +ve
Gram -ve
Acid fast
Gram +ve classification
Cocci
Spore forming rods
Non spore forming rods
Cocci classification
Streptococcus - pneumonia, pharyngitis, cellulitis
Staphylococcus - abscess of skin + other organs
Spore forming rods classification
Anaerobic
Aerobic
Anaerobic classification
Clostridium
Tetanus, gas gagrene, botulism
Aerobic classification
Bacillus (Anthrax)
Non spore forming rods classification
Non filamentous
Filamentous
Non filamentous classification
Corynebacterium (Diptheria)
Listeria (meningitis)
Filamentous classification
Actinomycetes (Actinomycosis)
Nocardia
Nocardiosis
Gram negative classification
Cocci
Facultative
Aerobic
Anaerobic
Cocci
Neisseria
Gonorrhea, meningitis
Facultative
Straight
Curved
Straight classification
Respiratory
Zoonotic organisms
Enteric organisms
Respiratory organisms
Haemophilus (meningitis)
Bordetella (whooping cough)
Legionella (Pneumonia)
Zoonotic organisms
Brucella (Brucellosis)
Francisella (Tularemia)
Pasteurella (Cellulitis)
Yesinia (plague)
Enteric organisms
Escheria (UTI, diarrhea)
Enterobacter (UTI)
Serratia (Pneumonia)
Klebseilla (Pneumonia, UTI)
Salmonella (Endocarditis, Typhoid fever)
Shigella (Enterocolitis)
Facultative - curved organisms
Campylobacter (Enterocolitis)
Helicobacter (gastritis, peptic ulcer)
Vibrio (cholera)
Gram -ve - aerobic organisms
Pseudomonas (pneumonia, UTI)
Gram -ve – aerobic organisms
Bacteroids (Peritonitis)