Lecture 5+6+DLA Flashcards
cell wall synthesis inhibitors
B lactams (penicillin, methicillin, cephalosporin)
vancomycin
lipoglycopeptides (telavancin and oritavancin)
DNA synthesis inhibitors
fluoroquinolones (ciprofloxacin)
cellular membrane dysfunction meds
lipopeptides (daptomycin)
folate synthesis inhibitors
sulfamethoxazole (trimethoprim)
protein synthesis inhibitors (30s)
aminoglycosides (doxycycline)
protein synthesis inhibitors (50s)
Oxazolidinones (linezolid and tedizolid)
erythromycin
broad spectrum antibiotic
targets most bacteria
new gen B lactams (cephalosporins)
narrow spectrum antibiotic
very targeted therapy that works on a limited amount of bacteria
Ex. penicillin G
cross resistance
resistance mechanism confers resistance to different
classes of antibiotics
ex. Pseudomonas efflux pump
intrinsic resistance
all isolates are naturally resistant
ex. Mycoplasma
acquired resistance
only some isolates have become resistant
ex. MRSA (Methicillin Resistant Staph aureus)
plasmid mediated resistance
Antibiotic Resistance genes (Abr) are highly mobile via conjugation
phage mediated resistance
(Abr) are highly mobile via transduction
chromosomal resistance
highly stable
spontaneous mutation
incorporation of donor DNA, donor pro-phage, or plasmid
rich/ complex media
Contains growth nutrients from complex biological source (ie. Yeast) to grow a variety of microbes
defined media
Contains very specific defined ingredients that are tailored for an organism’s growth requirements
Can be used to determine the growth effects on a specific nutrient ( such as swapping glucose for sucrose)
selective media
contains components that select for the growth of specific organisms.
Limits growth of others
differential media
allows differentiation of growing bacteria based on different characteristics
Assists with classification
MacConkey agar
allows for growth of E.coli and Salmonella restricting growth of other Gram + bacteria, especially for fecal samples
why can adding lactose to agar be important
Lactose is added to identify bacteria that ferment lactose with a pH pink color indicator
E.coli will ferment lactose
salmonella will not ferment lactose
Lowenstein-Jensen Agar
specific for Mycobacterium tuberculosis
very lipid rich
Thayer-Martin Agar
will grow Neisseria gonorrhea
chocolate agar with antibotics will prevent growth of usual flora
the growth calculation equation
colony forming units / amount plated mL x dilution factor
growth dynamics: growth curve
lag- newly inoculated cells; adjust to environment; pop is sparse
exponential- growth occurs at max rate; continues as long as the environment is right
stationary- population reaches max number
rate of death = rate of growth
death- decline in growth rate
depletion of nutrients
Psychrophiles and Psychrotrophs
growth best at cold temps <25° C
relevant to food pathogens
Mesophiles
grow best at human body temp
most human pathogens are in this range
Thermophiles and Hyperthermophiles
grow best at high temps >65°C
Associated with thermal vents
Neutrophiles
Acidophile
Alkaliphiles
Neutrophiles = most human pathogens live between 6 and 8
acidophile = grow at a low pH
Lactobacillus as vagina microbiota (pH4)
Helicobacter pylori in stomach (pH2)
alkaliphiles = high pH due to high levels of minerals (pH 9-11)
Halophiles
Xerotolerant
Osmotolerant
Halo = low Aw due to high NaCl concentrations
Associated with saltwater microbes
ex. Vibrio species including V. cholerae
xero = can grow in lower Aw
osmo = can withstand high osmotic pressure due to high solute concentration
example of catalase + and -
catalase testes for oxygen consumption
+ = staph
- = strep
obligate aerobe
will be SOD and catalase +
02 is needed
Ex: Mycobacterium tuberculosis
Facultative aerobes
Can use both aerobic respiration (using O2) and
fermentation/anaerobic respiration (without O2)
will be both SOD and catalase +
Ex: E.coli
Aerotolerant
can grow in the presence or absence of O2
Will be SOD +
Catalase -
ex: strep
obligate anaerobe
Cannot use O2, die when exposed to O2
negative for both catalase and SOD
ex: Clostridium difficile
Microaerophiles
require lesser amounts of oxygen
SOD will be +
catalase can be -/+
ex: Helicobacter pylori
what is a chi- square test used for?
It is used to test if there is an association/ relationship between 2 categorical variables
example: association between smoking and race for cancer
what is a T-test used for
Two-sample t-tests are statistical tests used to compare the means of two groups.
paired T-tests are used for dependent
unpaired T-tests used for independent
what is a paired T-test used for
is a statistical test that compares the averages/means and standard deviations of two related groups to determine if there is a significant difference between the two groups
dependent
what is an ANOVA used for
test of hypothesis that is appropriate to compare a continuous variable in three (3) or more independent comparison groups
The (one-way) ANOVA procedure is used to compare the means of the comparison groups
what does regression analysis allow?
description: relationships among the dependent variables
estimation: the values of the dependent variables
prognostication: risk factors that will influence that outcome
monotonic relationship?
Correlation is a measure of a monotonic association between 2 variables
ex: both variables will increase
one will increase and other will decrease
sometimes a linear line
covariance
The degree to which the change in 1 continuous variable is associated with a change in
another continuous variable
Pearson’s Correlation Coefficient
describes a linear relationship
describes the strength and direction of the relationship
denoted by r (closer to 1 the stronger the relationship)
Spearman’s Rank Correlation
used for data that is monotonic but nonlinear
similar interpretation to r (-1 - +1)
