Exam 2 Material Flashcards
metabolism
pertains to all chemical reactions and physical workings of the cell
anabolism
any process that results in the synthesis of cell molecules and structures
a building and bond-making process that forms large macromolecules from smaller ones
Does anabolism require energy?
anabolism does require the input of energy
catabolism
breaks the bonds of larger molecules into smaller molecules
Does catabolism require energy?
catabolism releases energy
reducing power in catabolism
electrons available in NADH and FADH2
aerobic respiration
a series of reactions that converts glucose to CO2 and allows the cell to recover significant amounts of energy
how does aerobic respiration work?
utilizes glycolysis, the krebs cycle, and the respiratory chain
relies on free oxygen as the final electron and hydrogen acceptor
characteristic of many bacteria, fungi, protozoa, and animals
anaerobic respiration
used by the strictly anaerobic organisms and those who are able to metabolize with or without oxygen
involves glycolysis, the krebs cycle, and the electron transport chain
uses nitrate, sulfate, carbonate, and other oxidized compounds as final electron acceptors
fermentation
incomplete oxidation of glucose
oxygen is not required
organic compounds are terminal electron acceptors
How do all three metabolic pathways begin?
glycolysis
glycolysis
turns glucose into two copies of pyruvic acid
respiratory chain
a chain of special redox carriers
embedded in the cytoplasmic membrane in bacteria
receives electrons from reduced carriers generated by glycolysis and the krebs cycle and passes them in a sequential and orderly fashion from one redox molecule to the next
What are the principal compounds in the Electron Transport chain?
NADH dehydrogenase
flavoproteins
coenzyme Q(ubiquinone)
cytochromes
cytochromes
contains a tightly bound metal ion in their center that is actively involved in accepting electrons and donating them to the next carrier in the series
oxidative phosphorylation
the coupling of ATP synthesis to electron transport
each NADH that enters the electron transport chain can give rise to 3 ATP
electrons from FADH2 enter the electron transport chain at a later point and have less energy to release, so only 2 atp
What is a potential side reaction of the respiratory chain?
incomplete reduction of oxygen to the superoxide ion and hydrogen peroxide
What enzymes do aerobes produce to deal with toxic oxygen products?
superoxide dismutase
catalase
streptococcus lacks these enzymes but still grows well in oxygen due to the production of peroxidase
What is the final step of the anaerobic respiration?
utilizes inorganic, oxygen-containing ions, rather than free oxygen, as the final electron acceptor
denitrification
some species of pseudomonas and bacillus possess enzymes that can further reduce nitrite to nitritic oxide, nitrous oxide, and even nitrogen gas
When is the fermentation strategy used
by organisms that do not have an electron transport chain
What is the benefit of fermentation
rapid rate for glycolysis
adaptation of faculative and aerotolerant anaerobes
What are some products of fermentation?
alcoholic beverages, solvents, organic acids, vitamins, antibiotics, and hormones
alcoholic beverages
ethanol and CO2
solvents
acetone, butanol
organic acids
lactic acid, acetic acid
what is the chromosomal size of e. coli
about 5 million bp
what is the chromosomal size of haemophilus influenza
about 1.8 million bp
what is the human chromosomal size
about 3.12 BILLION bp
what is the gene number in e. coli
about 4300 genes
what is the gene number of h. influenza
about 1650
what is the gene number in humans
about 19-20 thousand genes
What is the human cell forms of genome?
about 19000-20000 genes on 23 chromosome pairs
How many chromosomes does e. coli have?
a single chromosome, with 4288
how many genes do the smallest viruses have?
4-5 genes
eukaryotic chromosomes
DNA would around histone proteins, located in the nucleus, diploid(in pairs) or haploid(single), linear appearance
bacterial chromosomes
DNA condensed into a packet by means of histone-like proteins
one, two, or three circular chromosomes
bacteria/archaea/viruses/organellar DNA
mostly DNA coding genes
eukaryote nuclear DNA
mostly non-coding DNA
replication
DNA makes new DNA
transcription
DNA makes mRNA
translation
RNA links amino acids to make proteins
what are some exceptions to the pattern of information transfer
retroviruses convert RNA to DNA
RNA viruses convert RNA to other RNA
What shape does DNA mostly take?
circular
Where is DNA unwound?
replication fork is where DNA is unwound
vertical gene transfer
transfer of genes from parents to progeny; different generations
point mutations
errors in DNA replication
neutral vs advantageous
How is horizontal gene transfer different from vertical gene transfer?
transfer of genes from one organism to another
same or different species
recombination
DNA rearranged or combined to produce a new nucleotide sequence
vertical gene transmission
phylogenetic tree
horizontal
network
What occurs during recombination?
bacteria have no exact equivalent to sexual reproduction
instead they have an event in which one bacterium donates DNA to another bacterium
end result is a new strain different from both donor and original receptors
What genes occur with recombination?
provide genes for resistance to drugs and metabolic poisons, new nutritional and metabolic capabilities, and increased virulence and adaption to the environment
recombinant
any organism that contains genes that originated in another organism
horizontal gene transfer
any transfer of DNA that results in organisms acquiring new genes that did not come from parent organisms
plasmids
small, circular pieces of DNA
contain their own origin of replication
not necessary for survival
can carry useful traits
chromosomal fragments
must integrate into the bacterial chromosome in order to be replicated
function of conjugative plasmids
transfer of dna from one cell to another
example of conjugative plasmid
f factor
size of conjugative plasmid
95-100
hosts of conjugative plasmids
E. Coli, Salmonella, citrobacter
function of R plasmids
carry antibiotic resistant genes
example of R plasmid
Rp4
size of R plasmid
54
hosts of R plasmid
pseudomonas and gram negative
function of metabolic plasmids
carry genes for enzymes
example of metabolic plasmid
CAM
size of metabolic plasmid
230
hosts of metabolic plasmid
pseudomonas
conjugation
mode of exchange in which a plasmid or other genetic material is transferred by a donor to a recipient cell via a direct connection
gram-negative conjugation
fertility(f factor) allows the synthesis of a conjugating pilus
a plasmid that has genes that direct synthesis of conjugative pilus
F+ cells
cell that has the plasmid
F- cells
cell that lacks the plasmid
How is contact made between F+ and F- cell?
contact is made when pilus grows out from the F+ cell, attaches to the surface of the F- cell, contracts, and draws the two together
gram-positive conjugation
an opening is created between two adjacent cells
replicated DNA passes across from one cell to another
How does the F factor transfer work?
donor cell (F+) makes a copy of its F factor
transmits this to a recipient (F-) cell
turns it into an F+ cell capable of producing a pilus and conjugating with other cells
how does conjugation with resistance plasmids work?
bear genes for resisting antibiotics
commonly shared among bacteria through conjugation
transformation
nonspecific acceptance by a bacterial cell breaks into fragments small enough to be accepted by a recipient cell
what is transformation faciliated by?
by DNA-binding proteins on the cell wall
Does transformation require special appendages?
no special appendages; donor and recipient cells do not have to be in direct contact
bacteriophage
virus that only infects bacteria
transduction
donor and receipient bacteria must be the same species due to most specificity of viruses for host cells
generalized transduction
bacteriophage serves as a carrier from a donor cell to a recipient cell
random fragments of disintegrating host DNA are taken up by the bacteriophage
specialized transduction
highly specific part of the host genome is regularly incorporated into the virus
when activated, prophage DNA separates from the bacterial chromosome, carrying a small segment of host genes with it
lysogenic conversion
temperate phage changes phenotype of its host
immunity to virus
phage may express pathogenic toxin or enzyme
transposons
transposable elements capable of shifting from one part of the genome to another
can be transferred from a chromosome to plasmid or vice versa or from one cell to another in bacteria
what are transposons a part of?
changes in traits such as colony morphology, pigmentation, and antigenic characteristics
replacement of damaged DNA
intermicrobial transfer or drug resistance(in bacteria)
How does genetic regulation of protein synthesis occur?
control mechanisms ensure that genes are active only when they are required
enzymes produced as needed
regulation in bacteria, archaea, and eukaryotes
where are operons found
only found in bacteria and archaea
operons
consist of a coordinated set of genes regulated as a single unit
inducible or repressible
catabolic operons
induced (“turned on”) by the substrate of the enzyme(s) fir which the structural genes code
only produce the enzyme when the substrate is present
repressible operons
anabolic enzymes, turned off by the product synthesized by the enzyme
Lactose Operon System
best understood cell system for explaining control through genetic induction
What are the three main features of the Lac Operon system?
regulator, control locus, structural locus
regulator
composed of the gene that codes for a protein capable of repressing the operon(a repressor)
what is the control locus composed of
the promoter and operator
promoter
recognised by RNA polymerase
operator
on/off switch
structural locus
made of three genes coding for different enzymes
When does the lac operon function?
only functions in absence of glucose or if cell needs additional energy
What is the preferred carbon and energy source of lac operon system?
glycose preferred can be used immediately, no operon induction required
What happens to the lac operon system when glucose is present?
lac operon is inactive, regardless of the lactose availability in the environment
what is phase variation
when bacteria turn on or off a complement of genes that leads to obvious phenotypic changes
heritable
mediated by regulatory proteins
what area of cell does phase variation typically impact
most often applied to traits affecting the surface of the bacterial cell that promote attachment to host cells
neisseria gonorrhoea
produce attachment fimbrae
streptococcus pneumoniae
produce a capsule
Can bacteria change components on cell surface?
can change the ones that mark them for targeting by the hosts immune system
what is the typical defensive mechanism of bacteria
molecular scissors
What do the restriction endonucleases do
protects bacteria against incompatible DNA of bacteriophages(virus of bacteria) or plasmid
what are restriction enzymes capable of
capable of recognizing foreign DNA and breaking phosphodiester bonds between adjacent nucleotides
palindrome
sequence of DNA that are identical when read from the 5’ to 3’ direction on one strand and the 5’ to 3’ direction on the other strand
restriction enzyme action
the cleavage catalyzed by the restriction endonuclease ECORI. Enzyme makes two staggered cuts on the two DNA strands. The resulting “sticky” ends that can be used for molecular cloning
How are restriction enzymes named?
first three letters of a restriction enzymes name are abbreviations of the bacterial species from which the enzyme has been isolated
fourth letter represents particular bacterial strain
Eco
for E. Coli
HIn
for H. influenzae
What does the fourth letter represent in restriction enzyme name
represents the particular bacterial strain
gene therapy
replacing a faulty gene responsible for disease with a gene from a healthy organism
CRISPR
allows scientists to cut an organism’s DNA where they want to
CRISPR
system found in bacteria that can cause very specific cuts in genes
regions in the bacterial genome that help defend against invading viruses
What does CRISPR stand for
clustered regularlly interspaced short palindromic repeat
CRISPR mechanism
memory bank of incoming nucleic acid sequences for surveillance against foreign DNA
ex vivo applications
cells of a patient are isolated, manually edited, and delivered back to the same patient
what are the three main potentials of ex vivo applications
cancer immunotherapy
treatment of hereditary diseases
viral infection inhibition
in vivo application
the crispr-cas system is deliverd by various vectors to disease-associated cells or organs of the body to treat
antimicrobial drugs
reduced the incidence of certain infections, but they have not eradicted infectious disease and probably never will
what are doctors worried about today?
that we are entering a post-antibioitic era
goal of antimicrobial chemotherapy
administer a drug to an infected person that destroys the infective agent without harming the host’s cells
what must a drug be able to do
be easy to administer and able to reach the infectious agent anywhere in the body
be absolutely toxic to the infectious agent and absolutely nontoxic to the host
remain active in the body as long as needed and be safely and easily broken down and excretef
characteristics of the ideal antimicrobial drug
toxic to the microbe but nontoxic to host cells
microbiocidal(kill microbe) rather than microbiostatic(inhibit their growth)
relatively soluble
remains potent long enough to act and is not broken down
prophylaxis
use of a drug to prevent infection of a person at risk
antimicrobial chemotherapy
the use of drugs to control infection
antimicrobials
all-inclusive term for any antimicrobial drug, regardless of its origin
antibiotics
substances produced by the natural metabolic processes of some microorganisms that can inhibit or destroy other microorganisms; generally the term is used for drugs targeting bacteria and not other types of microbes
semisynthetic drugs
drugs that are chemically modified in the laboratory after being isolated from natural sources
synthetic drugs
drugs produced entirely by chemical reactions
narrow-spectrum(limited)
antimicrobials effective against a limited array of microbial types
broad-spectrum(extended)
antimicrobials effective against a wide variety of microbial types
are antibiotics natural or man-made
natural metabolic products of bacteria and fungi
why are antibiotics produced?
to inhibit the growth of competing microbes in the same habitat(antagonism)
what generas are most antimicrobial drugs made from
bacteria in the genera streptomyces and bacillus
molds in the genera Penicillium and cephalosporium
what factors must be known before antibiotic treatment can begin?
identity of the microorganism causing the infection
the degree of the microorganism’s susceptibility to various drugs
overall medical condition of the patient
when should identification of infectious agents begin?
as soon as possible, but
before antimicrobial drugs are given
what is typically the most rapid method of detection of infectious agents
direct examination of body fluids, sputum, or stool samples is a rapid method
what do doctors begin treatment based off of?
basis of immediate findings and informed guesses
what organisms require testing for drug resistance?
straphylococcus species
neisseria gonnorhoeae
enterococcus faecalis
aerobic, gram-negative intestinal bacilli
what occurs with the Kirby-Bauer technique?
surface of an apgar plate is spread with test bacterium using a sterile cotton swab
small discs containing prepared amount of antibiotic are placed on the plate
zone of inhibition surrounding the discs is measured and compared to standard
what is kirby-bauer most typically
less effective for?
anaerobic, highly fastidious(has complex or particular nutritional needs), or slow-growing bacteria
how do disc diffusion tests occur?
agar disc with a bacterial isolate distributed evenly all over its surface after incubation. after inoculation, the antibiotic-containing disks are dropped on plate and is incubated
minimum inhibitory concentration
the smallest concentration(highest dilution) of drug that visibly inhibits growth
what is the MIC useful for determining
the smallest effective dose and providing a comparitive index against other antimicrobials
how many discs is the kirby-bauer test able to potentially have
up to 12 antibiotic disks
what is an E-test
a commercially prepared strip that produces a gradient of antibiotic concentration when placed on agar plate
tube dilution test
more sensitive and quantitative than kirby-bauer
antibiotic is diluted serially through tubes of liquid nutrient from right to left
all tubes are innoculated with identical amount of a test bacterium and then incubated
what does the response to treatment typically look like in vitro and invivo
invitro activity of a drug is not always correlated with the invivo effect
why would an antimicrobial treatment fail?
inability of the drug to diffuse into that body compartment(brain, joints, skin)
resistant microbes in the infection that did not make it into the sample collected for testing
an infection caused by more than one pathogen(mixed), some of which are resistant to drug
patient did not take drug correctly
How do we minimize drug toxicity?
choose drug with high selective toxicity for the infectious agent and low human toxicity
therapeutic dose
minimum dose per kg of body weight that stops pathogen growth
toxic dose
maximum dose tolerated by the patient
what is the therapeutic index
the ratio of the dose of the drug that is toxic to humans as compared to its minimum effective(therapeutic) dose(TI=toxic dose/MIC)
is a drug with a higher therapeautic index or a lower therapeutic index safter
higher therapeutic index
who was penicillin discovered by
alexander fleming in 1928
he observed penicillin activity on contaminated plate
did not think it could be developed further
who was the effectiveness of penicillin demonstrated by
florey, chain, and heatley
what is the goal of antimicrobial drugs
disrupt cell processes or structures of bacteria, fungi, or protozoa
inhibit virus replication
interfere with function of enzymes required to synthesize or assemble macromolecules
destroy structures already formed in the cell
selectively toxic
kill or inhibit microbial cells without damging host dissues
what drugs are most toxic to humans
drugs that act upon a structure common to both the infective agent and the host cell
goals of chemotherapy
disrupt the structure or function of an organism to the point where it can no longer survive
antimicrobial drug categories
inhibition of cell wall synthesis
inhibition of nucleic acid structure and function
inhibition of protein synthesis
interference with cytoplasmic membrane structure and function
inhibition of folic acid synthesis
broad-spectrum drugs
effective against more than one group of bacteria
example of broad-spectrum drug
tetracycline antibiotics
narrow-spectrum drugs
target a specific group
example of narrow-spectrum drug
polymyxin
what spectrum typically causes superinfection
broad-spectrum drugs
penicillins
original was narrow-spectrum and susceptible to microbial counterattacks
molecule has been altered and improved over the years
drug resistance
an adaptive response in which microorganisms begin to tolerate an amount of drug that would normally be inhibitory
why does drug resistance occur
due to the genetic variability and adaptability of microbial populations
natural intrinsic resistance
resistant to antibiotics they produce
a fixed trait
chromosomal drug resistance
usually results from spontaneous random mutation
slight changes in drug sensitivity can be overcome with larger doses of drug
persisters
slowing of metabolism so that the microbe cannot be harmed by the antibiotic
resistance factors
plasmids containing antibiotic resistance genes
how can resistance factors be transferred
through conjugation, transformation, or transduction
transposons
also duplicate and insert genes for drug resistance into plasmids
what is happening with antibiotics in the medical field
antibiotics are entering a resistance era
superbugs
bacterium(or other microbe) that carries several antibiotic-resistance genes
what are the urgent threats
clostridioides difficle(C.diff)
carbapenem-resistant enterobateriaceae(CRE)
drug-resistant neisseria gonnorrhae
what are the serious threats
multidrug-resistant acinetobacter
drug-resistant campylobacter
fluconazole-resistant candida
what are the concerning threats
vancomycin-resistant staphylococcus aureus
erythyromycin-resistant group A streptococcus
clindamycin-resistant group B streptococcus
what drug is effective against most gram-negative rods
colistin
CRISPR interference
treat antibiotic-resistant infections
target only cells infected with the infectious bacterial agent
CRISPR-CAS delivered to cell via phage or conjugation
CRISPR destroys antibiotic resistance genes
bacteriophages
only used in eastern european countries
narrow specificity; only infect one species of bacterium
probiotics
preparations of live microorganisms fed to animals and humans to improve intestinal biota
safe, effective
useful in the management of food allergies
prebiotics
nutrients that encourage the growth of benefical microbes in the intestine
fructans encourage the growth of Bifidobacterium in the large intestine
discourage the growth of potential pathogens
fecal transplants
used to treat recurrent clostridioides(C.diff) infection and ulcerative colitis
how does the fecal transplant work
transfer of feces from a healthy patient via colonoscopy
work is underway to develop a pill containing the species to re-colonize the colon
what organs can drugs adversely affect
liver(hepatotoxic), kidney(nephrotoxic), gastrointestinal tract, cardiovascular system and blood-forming tissue, nervous system(neurotoxic), respiratory tract, skin, bones and teeth
what is the major toxic reaction of penicillin G
rash, hives, watery eyes
what is the major toxic reaction of carbenicillin
abnormal bleeding
what is the major toxic reaction of ampicillin
diarrhea and enterocolitis
what is the major toxic reaction of cephalosporins
inhibition of platelet function
decreased circulation of WBC; nephritis
what are the major toxic reactions of tetracyclines
diarrhea and enterocolitis
discoloration of tooth enamel
reactions to sunlight
what is the major toxic reaction of sulfonamides
formation of crystals in kidney; blockage of urine flow
hemolysis
reduction of number of rbc
what are the major toxic reactions of polymyxin(colistin)
kidney damage
weakened muscular responses
what are the major toxic reactions of quinolones(ciprofloxacin, norfloxacin)
headache, dizziness, tremors, GI distress
what are the major toxic reactions of rifampin
damage to hepatic cells
dermatitis
allergy
drug acts as an antigen that stimulates an allergic response
can be provoked by the intact molecule or by substances that develop from the body’s metabolic alternation of the drug
what occurs with the first contact with a drug in regard to allergies
sensitization
what happens with the second exposure for allergies
can lead to hives, respiratory inflammation or anaphylaxis
biota
normal microbial colonists of healthy body surfaces
normally consist of harmless or beneficial bacteria
few may be pathogens
what do broad-spectrum drugs do to biota
destroy healthy biota; along with pathogens
superinfection
microbes that were once small in number overgrown when normal resident biota are destroyed by broad-spectrum antibiotics
what are examples of superinfection
urinary tract infection caused by E.coli treated with antibiotics
overgrowth of clostridium difficile invades the intestinal lining and releases toxins
high G+C gram positive bacteria
actinomycetes(common in soil, lack flagella, filamentous)
produce filaments, forming mycelium analogous to mycelium of fungi
aerial hyphae differentiate into spores(exospores) for survival and dispersal
what is the key genera of high G+C gram positive bacteria
streptomyces
useful metabolites(antibiotics, anticancer and immunosuppressive drugs, antihelmiths, antifungals)
streptomyces
filaments grow by hyphal tip extension
aerial mycelium
form exospores
when do exospores develop
in response to nutrient deprivation
how are spores of strepmyces distributed
by wind
what is the G+C content of streptomyces
69-78%
where are streptomyces typically found
in the soil(1-20% if culturable bacterial population)
what do the enzymes of streptomyces do?
degrade variety of naturally occuring organic compounds(chitin, keratin, latex) agar, aromatic compounds including xenobiotic
how many distinct antibiotics are produced by streptomyces
over 500 distinct antibiotics
what does the microbe streptomyces orientals produce
vancomycin
antibiotic; cell wall inhibitor
what does the microbe S. mediterranel produce
rifamycin
antibiotic; transcription inhibitor
what does the microbe S. rimosus produce
tetracycline
antibiotic; protein synthesis inhibitor
what does the microbe S. venezuelae produce
chloramphenicol
antibiotic; protein synthesis inhibitor
what does the microbe S. clavuligerus produce
clavulanic acid
B-lactase inhibitor
what does the microbe S. nodosis produce
amphotericin B
antifungal
what does the microbe S. noursei produce
nystatin
antifungal
what does the microbe S. peucetius produce
daunorubicin, doxorubicin, epirubicin
anticancer
what does the microbe S. verticillus produce
bleomycin
anticancer
mycobacterium
straight or slightly curved rods that sometimes branch or form filaments
aerobic
filaments readily fragment into rods and coccoid bodies
very slow growing on culture media
genus nocardia
develop a substrate mycelium that readily breaks into rods and coccoid elements
some also form an aerial mycelium and conidia
impact of nocardia
most are free-living saprophytes
can degrade many molecules, bioremediation applications
some are opportunistic pathogens causing nocardiosis
nocardiosis
infect lungs; can infect central nervous system
genus propionibacterium
anaerobic or aerotolerant
found on skin and in digestive tract of animals
in dairy products such as cheese
proionbacterium acne
involved in the development of body odor and acne
frankia
8 nonlegumionous tree species
microaerophilic
symbiotic fixation of N2
bifidobacterium
anaerobic
ferment carbohydrates to produce acetic and lactic acids, but not co2
human mouth and gut microbiome
pioneer colonizer of human intestinal tract especially when babies are breast fed
what are the hierachial levels in order
domain, phylum, class, order, family, genus, species
what are the four most common phyla
proteobacteria(gram-negative)
actinobacteria(gram-positive)
firmicutes(gram-positive)
bacteriodetes(gram-negative)
what are the lineages of 16S rRNA
alphaproteobacterium
betaproteobacterium
gammaproteobacterium
deltaproteobacterium
episilonproteobacterium
Family enterobacteriacease
gram negative rods
soil, water, or intestines of humans and animals
harmless symbionts to disease-causing pathogens
ferment sugars to a variety of end products
important enteric bacteria
escherichia
universal inhabitants of intestinal tract of humans
synthesize vitamins for host
important pathogenic enteric bacteria
salmonella:typhoid fever and gastroenteritis
shigella: bacillary dysentery
klebsiella: pneumonia
yersinia: plague
E. coli, proteus, serratia, citrobacter
nitrogen fixation
N2 to NH4+
nitrification
oxidation of ammonia generates energy
denitrification
nitrate or nitrite used as final electron acceptor in anaerobic respiration
phylum bacteroidetes
variety of terrestial and aquatic
degrade complex carbohydrates
sewage treatment plans
chemoheterotrophs
obligate anaerobes, degrade complex plant carbohydrates, cellulose
animal microbiome
oral cavity and intestinal tract
break down plant materials that may be toxic to us
phylum chlamydiae
gram-negative
obligate intracellular parasites
must grow and reproduce inside host cells
although known for ability to cause disease, many grow within hosts
genus chlamydia
nonmotile, coccoid, gram-negative
cell walls lack muramic acid
obligate intracellular parasites with unique developmental cycle
elementary body
small, dense cell resistant to drying, dispersal
specialized for infectious transmission
reticulate body
larger vegetative cell divides by binary fission
non infectious
function is to produce inoculum for infectious transmission
differentiate back into EB, lyses cell
transmission of chlamydiae
transmission of elementary bodies
airborn invaders of respiratory system
sexually-transmitted disease
putrefaction
the decomposition of organic matter with formation of foul-smelling incompletely oxidized products
important species of clostridium
C. botulinum(ingested, one of the deadliest toxins)
C. tetani(produce toxins that interfere with muscle contractions)
C. perfringens
secretes protein toxins that can cause food poisoning or gas gangrene
enzyme destroys tissues, releasing proteins for fermentation
causes painful swelling and weird skin color
bacillus
usually aerobic
form endospores
antibiotics
toxins
bacillus anthrax
anthrax toxin
skin, lungs, intestinal
non-endospore forming bacillales
listeria
soils, opportunistic pathogen, foodborne illness
colder temps, refrigerator
mild to fatal forms of meningitis
family staphylococcaceae
faculatively anaerobic, nonmotile cocci
no endospores
irregular clusters
normally associated with warm-blooded animals in skin, skin glands, and mucous membranes
staphylococcus aureus
most important human staphylococcal pathogen
major cause of common food poisoning
virulence factors(coagulase which causes blood plasma to clot)
S. aureus antibiotic resistance
methicillin resistant staphylococcus aureus
cephalosporins
nosocomal infections(hospitals)
community-associated MRSA(CA-MRSA)
staphylococcus epidermidis
common skin resident
infections of patients with lowered resistance
lactococcus
genus of dairy significance
ferment lactose to lactic acid
lactoccus lactis: buttermilk and cheese
streptococcus
ferment sugars to lactic acid,
found in mouth and respiratory tract
three groups of streptococci
pyogenic streptococcus(e.g. s. pyogenes: streptococcus-sore throat, rheumatic fever
oral streptococci(e.g. s. mutans: dental caries; e.g. s. pneumoniae-lobar pneumonia and middle ear infections)
mycoplasma
lack cell walls; naturally resistant to antibiotics that target cell wall
small genomes
colonize mucuos membranes; diseases of respiratory and urogenital tract
