Intro to bacteria Flashcards
gram positive rods
Bacillus, clostridium, corynebacterium, lactobacilli, listeria, propionibacterium
Gram negative cocci
Moraxella, neisseria
gram negative Non enteric rods
bartonella, bordetella, brucella, burkholderia, francisella, haemophilus, legionella
gram nefative Enteric rods
campylobacter, enterobacter, eschericia, helicobacter, klebsiella, proteus, salmonella, shigella, vibrio, yersinia
curved shapes
helical, spiral (VIBRIO)
diplococci example
streptococcus pneumoniae
streptococci example
streptococcus pyogenes
staphylococci example
all staphylococcus
tetrad example
sarcina
coccobacillus
very short fat rod
pleomorphic
used for young or old when we are unsure of their shape.
acid fast stain used for
mycobacterium tuberculosis and nocardia spp.
colors for acid fast
for ZN and Kinyoun stain(cold) red and pink= acid fast, blue green= non acid fast. for FC stain, yellowish green against a black ground =acid fast.
flagella are never found on
cocci
Monotrichous example
vibrio
amphitrichous example
spirillum
lophotricous esxample
pseudomonas sp
lateral pertirchous example
proteus.
helical filament in flagella is composed of
flagellin H- antigen
rotor/bushing for flagella
S ring and M ring/L ring P ring
rotation of flagella to produce smooth swimming motion
counter clockwise
pilus
made of pilin, F-pilus is sex pilus and found only on gram -ve
Fimbriae
used for adhesion and colinization predominantly gram-ve, some gram +ve (Corynebacterium renale, actinomyces naeslundii)
glycocalyx
AKA capsule, slime layer and s-layer
surrounds cell, Slime layer is poorly organizatio and weak attachment to cell wall (staph, epidermis)- this is easily removed and can attach to plastics.
Capsule- organised adheres to cell wall (K-antigen (M-strep pyogenes, V1 for slamonellae)
external mucilagnous is made of
polysaccharide (EPS ) except bacillus anthracis which is polypeptide
function of glycocalyx
adherence (streptococcus mutans) using glucans and fuctans
Antigenic activity- S. Pneumoniae, H. Influenzae,
Antiphagocytic- strep. pneomoniaeprevention of neutrophil killing of engulged bacteria(lysosome contents do not have direct access to interior of the bacterial cell
prevention of PMN migration- bacteroides fragillis- capsule of succinic acid released that paralyzes PMN leukocyte
Toxicity to host cell- B. fragillis induces abscess
Protection- anaerobes from oxygen, dessiccation and nutrient loss.
Quellung reaction
swelling reaction indicates presence of capsule, antiserum +bacteria=swelling specific antisera capsular K/< antigens for typing.
backbone of cell wall
peptidoglycan NAM and NAG which are Beta 1-4 glycosidic bonds. provides rigidity and strength in gram positive- L-lysine, in gram negative Diaminopimelic acid for tetrapeptide linakge.
Gram +ve
thick peptidoglycan, teichoic acids (lipoteichoic acid, acidic anionic polysacc’s Glycerol/ribitol(bunds protons, cations acts as adhesins and is a virus receptor site. have MTR proteins Group A- Streptococci and staph aureus.
some periplasmic space, more permeable
gram -ve bacteria
thin peptidoglycan layer, outemembrane has porins, braun proteins, and lipopolysacc (endotoxin) all have perplasmic space and porin proteins and are less penetrable.
LOS lipooligosaccharide is found in
bordetella pertussis, neisseria meningitidis, c. jejuni.
acid fast bacteria have
petidoglycan, arabinose, and galactose in polymers, arabinogalactan esterification produces mycolic acds that are waxy
lysozyme
breaks 1-4 bond betwen nam and nag.
spheroplast
portion of cell wall remains
protoplast
cell wall completely removed (more grame +ve bacteria.
penicillin
transpeptidases, penicillin binding proetins inhibits cross linkage
mycoplasma have in cytoplasmic membrane
sterols
periplasmic space
conatins nutrient transport protiens, nutrient acquisition enzymes proteases detoxifying enzymes beta lactamases, membrane derived oligosaccharides osmoprotectants
axial filaments
leptospira spirochetes, lack flagella
pathogenicity islands
carry 1 or more virulence genes, present only in pathogen genome. they differ from core genome in operon usage, located next to tRNA genes. associated with transposons. and often unstable.
pathogens with PAI’s
Gram +ve listeria, s. aureus, strep. etnerococcus faecalis, clostridium dificile
Gram -ve H. pylori, e coli, slamonella, shigella, yersinia, L. pneomophilia, P. aerugniosa, v. cholerae. Bacteroides fragillis
antibotioc resistant plasmid
R plasmid
matigng capabilities
F- plasmid
mesosomes are mainly seen in
gram positive bacteria.
endospores example
bacillus and clostridium
endospore structure
coat-keratin like, coretex-peptidoglycan, spore wall-peptidoglycan, cell wall germinating vegetative cell. core- contains compelte genetic material, protein synthesizing apparatus, energey generating system calcium dipicolinic acd.
outer membrane antigen
O antigen
flagella antigen
H antigen
capsule antigen
K antigen
Mycoplasmataceae
M.genitalium, hominus and U. urealyticum- smallest organism. no peptidoglycan, resistant to penicillin, cycloserine and lysozyme membrane is phospholipid (glycolipid and contains sterols. cytoplasm has only ribosmes and DNA. Diphasic colonies have a fried egg appearance (except M. Pneumoniae) they require a rich medium of sterols and proteins. THey have a unique orangells with a tapered tip and P1 adhesin, destruction H2O2 and o2 (in M. pneumoniae and M. Genitalium
Rickesttsiaceae
obligate intracellular pathogens (also orientia, ehrlichia, coxiella and ana plasma) are zoonotic. ROD/Coccobacillary shaped (pleomorphic.) don’t stain well have a cell wall structure with diaminopimelic acid. some have a capsule (r. prowazeki-endemic typhus.)
Anaplasmataceae and Coxiella
need to know E. Chaffeensis, E. ewingii, A. phagocytophilum, and c. Burnetti(. OIP’s
Chalmydiaceae
Chlamidya(trachomatis) and Chlamydophila(psittci and pneumoniae)
Chlamydia is man only- trachoma, inclusion conjunctivitis and lympobranuloma venereum.
Chlamydopihla- bronchitis, pneumnia, sinusitis, athersclerosis, meningopneumontis, hepatic and renal dysfunction conjunctivitis. birds–> man Zoonotic.
are OIC do not generate ATP, descendents of gram -ve, with 2 membranes but no peptidoglycan. has two forms the elementary body,- non replicating extracelluar used to induce endocytosis. metabolically inactive
Reticulate body or initial body- replicating, non infectious, adapted for intracellular growth, metabolically active.
Growth rate
time for cell to reproduce
Generation time
time for complete fission cycle , formation of each new bacterial cell, its growth and eventual division into 2 cells.
Lag stage
adjustment to the new environement undergo metabolism to synthesize what they need for cell growth
Log stage
generation time and growth rate of bacterial production remains constant
stationary stage
no inceas in cell numbers becaue you have cells dying which are replaced by the newly formed cells so your growth rate = 0
Death stage
cells are dying faste than they are formed.
examples of psycrophiles
flavobacterium, alcaligenes, and achromobacter
example of facultative psychrophile
staph aureus, l. monocytogenes.
bacteria are unble to grow below an Aw. of
.09 except Xerotolerant which have a lower Aw like salt tolerant baceria called halophiles which grow in a high concentration of solute. .65-.8
Biocides
physical or chemical agent used to control microbes, may be disinfectant, antiseptic or temperature
Disinfection
destruction of vegetative pathogens on inanimate surfaces, use physical or chemical methods
antisepsis
destruction of vegetative pathogens on living tissue, almost always cehmical method.
degerming
Removal of microbes from a limited area, mostly mechanical removal by alcohol soaked swab
sterilisation
destruction or removal of all forms of microbial life, usually under pressure or sterilising gas
santisiation
treatment intended to lower microbial counts to safe public health levels, maybe achieved with high temp washing or dipping into chemical disinfectatn.
Least resistant to most resistant to destruction
enveloped viruses, gram +ve, Larve non-enveloped, vegetative fungi, Gram -ve, fungal spores, small non-enveloped viruses, mycobacteria, endospores, Prions
Ethylene oxide
strong akylator–> reacts with guanine aof DNa and function groups of proteins.
Static vs. bacteria
qurtenary ammonium compounds, parachlorometaxylenol
Static/non functional vs mycobacteria
Iodophors, quarternary ammonium compounds(NF), parachlorometaxylenol, triclosan
Static, functional vs Bacterial spores
static- hydrogen peroxide, chlorine
Functional, formaldehyde, glutaraldehyde
Static vs. fungi
quarternary ammonium compounds, tricolosan
Static vs. viruses
alcohol, phenolics, quarternary ammonium compounds, parachlorometaxylenol
for high risk
inactivates viruses fungi, myco and spores, because it is being introduced into sterile body areas
for intermediate risk use
inactivates viruses, fungi, mycobacteria , usually comes in contact with mucous membranes, prior to use with immunocompromised, contaminated with particularly virulent or readily transmissble organisms.
for low risk
inactivates non-sporulating bacteria and lipid-enveloped viruses
alcohols effective against
bacteria, fungi, viruses, mycobacteria
chlorhexidine
bacteria, static for fungi, mycobacteria, some viruses
iodine and iodophores
bacteria, fungi, viruses, mycobacteria
Triclosan
bacteria, static fungi, static mycobacteria.
selective toxicity
minimal or no effect on host cells but maximum effect against infecting microorganism.
Conjugation
need F pilus which is only found on Gram -ve bacteria
Plasmid has the resistance genes and integrated plasmid ( the episome integrates into recipient DNA. Complete transfer of F plasmid = New F+ cell Incomplete+ cell remains f-, complete transfer with integration into chromome= HFR cell, Integgrated F plasmid cell can now transfer to new F- cell. transfer f plasmid plus some or all of chromosome.
Tranformation
some cells are competent like Haemophilus or streptococci they have DNA binding protein on the outside and can incorporate strands of broken DNA, Haemophilus from only Haemophulis, Sterpto from any bacteria.
Transduction
virulent and temperate,-
Virulent death of cell by lysis releasing new phage,
temperate, can swtich between virulent lytic phase and prophage,
Lysogeny, gene expression repressed for phage gene, but can be triggered under certain conditions
happens when a defective phage with bacterial resistant DNA is injected into another instead of the phage DNA. in temperate the defective phage and bacterial phage have been integrated and that gets injected and integarted into the new bacterial DNA.
lysogeny
when baceria are carrying a prophage.
Transposons
Non-homologous recombination, jumping genes, can move around within the cell from chromsome to chromosome or chromosome to plasmid.
Virulence factors
influence the microbes ability to cause disease, promote colonization of host, cause damage
they predominantly encoded by associated with mobile genetic elements.
large proportion located within, pathogenicity islands.
examples of Virulence factors
iron uptake systems, adhesins, pore forming toxins, superantigens, secreted lipases, secreted proteases, proteins transported by type I and III secretion systems, antibiotic resistance phenotype.
attachment requires
host cell receptors, and microbial surface componnents
attachment/adhearance is defined by
ability to adhere, favourable environment, presence/absence of normal microflora.
afimbrial ashesins
lipoteichoic acid- epithelial cells and buccal epithelial cells, lPS or LOS, gastric epithelial cells, macrophages, Mannans, epithelial mucosa.
methods of invasino
phagocytosis, bacterial and fungal invasins, interact with cell receptors and induce endocytosis. Host cell cytoskeleton rearrangment like internalin A: L. monocytogenes. Usually injected into host cell. membrane ruffling.
complement system evasion techniques
capsules, CB proteins, proteases, host cell mimicry
phacytosis evasion
capsules, type III secretion systems, intracellular parasitism. you can inhibit phagosome lysosome fusion, escape phagolysosome, inactivate oxygen radicals or degradative enzymes, produce a surfae componnent.
antigen processing evasion
interfere with MHC function and antigen processing
antibody evasion
Ig binding/inactivating proteins- binding of Fc domain of IgG or bacterial IgA proteases antigenic variation- phase variation is expression switchable on/off, multiple antigenic forms at different times.
Hyaluronic acid is used for
host cell mimicry
polysaccharide and Polyribose ribitol phosphate are compnents of
capsules.
evade complement and phagocytosis without capsule you use
extracellular prtoease, Pseudomonas aeruginosa uses Elastase which prevents opsonization and inactivates C3b and C5a, Streptococcus pyogenes uses C5a peptidase–> it inhibits phagocyte chemotaxis degrades C5a
evasion of macrophages and leukocytes
leukocidins–> kill neutrophils and macrophages,
Alter phospholipid metabolism by ADP ribosylation
these are typically HIGHLY invasive bacteria.
iron sequestration
specific surface receptors or through siderophore secretion, have a high affinity for iron.
biofilm
exopolymeric substance (EPS) is produced. seen in Central catheters and urinary catheters.
exotoxin
composed of polypeptide, toxoid formation, not usually fever. examples, btulism, tetanus, Cytotoxin, TSST-1 Diptheria.
classified according to: target site/cell, producing bacterium, mechanism of action, associated diseases.
encoded by plasmids and bacteriophages and you control via environmental regulators like pH and iron.
Class 1 exotoxin
membrane acting/binding- TSST-1, powerful T-cell mitogens, Superantigens, Toxic schock syndrome and rheumatic fever. they bind directly to t cell receptor.
class II exotoxin
membrane acting- like lecithinase of C. Perfringens or Alpha toxin or phospholipase c. destabilizes phospholipid.
pore formation- listeriolysin O also called CFT’s channell forming toxins.
Class III exotoxin
intracellular- A catalyitic, enzymatically attacks host cell function or structure. B- binding subunit, specific host cell surface glycoprotein or glycolipid. - ADP ribosylatransferase, Zinc metalloendoprotease, deamidase, glucosyltransferase.
AB- singel gene encodes for seingle peptide, diptheria toxin covalently linked.
A5B two genes encode A and B units and they are noncovalently associated- cholera toxin, enterotoxin.
toxoid
inactivated toxin, still antigent but do ont cause damage, used for diptheria and tetanus
survival of microbes
need to resist UV damage and drying.
