Bacteriology Module 1

Define colonization

presence of microbes WITHOUT disease

Define infection

invasion or growth of disease-causing microbes

What is the word for "cause of infection"

etiology

Define etiology

cause of infection

Define pathogenesis

mechanism by which a microbe causes disease

Define pathogenicity

ability of a pathogen to cause disease

Define virulence

degree of pathogenicity

How do pathogens cause disease to the host?

1. change normal physiology of host
2. deplete host nutrients
3. causes immune response
4. Mixture of above ways

What is the name for a bacteria with no cell wall?

mycobacteria

What are mycobacteria?

bacteria with no cell wall

What way do mycobacteria stain?

gram negative

What are the three types of pathogens (related to how pathogenic they are)?

obligate, primary, opportunistic

What is an obligate pathogen?

highly virulent in small numbers, no host susceptibility needed

What is a primary pathogen?

Medium virulence and needs some susceptibility of host

What is an opportunistic pathogen?

low virulence even in large numbers, needs host susceptibility

What are biofilms?

when bacteria come together in masses they cling to the surface through EPS production

What is quaram sensing?

When bacteria are in large masses they signal one another to synchronize gene expression

What are the three pathogen locations?

extracellular, obligate intracellular, facultative intracellular

What are some characteristics of bacteria?

prokaryote, no nucleus, binary fission, cell wall, singular/circular chromosome

What is a gram negative bacteria?

thin peptidoglycan outer membrane

What color do gram negative bacteria stain?

Pink

What is a gram positive bacteria?

thick peptidoglycan layer and NO outermembrane

What color does gram positive bacteria stain?

Purple

What is special about gram negative bacteria?

they release endotoxins upon death

What are flagella?

motility factors on bacteria

What are pili/fimbriae?

Adhere to host tissue through receptors

What are capsules?

outer coating to protect against phagocytosis

What are endospores?

dormant form of bacteria

What is polyphasic bacterial diagnosis?

Using multiple diagnostics to identify the bacteria

What is classic PCR used for?

Amplifying and detecting target nucleic acids

How is classic PCR seen?

Gel electrophoresis

What is real-time PCR?

uses fluorescent dyes to graph amplification

What does a low CT value mean?

more DNA (started amplifying faster)

What does a high CT value mean?

less DNA (started amplifying slower)

What is are examples of antigen detection diagnostics?

ELISA, PPD skin test, agglutination test

What does agglutination test measure?

antibody production

What does PPD skin test measure?

Host response/ cell mediated (are immune cells present)

Define seroconversion

antibodies developing after exposure to a pathogen or antigen

What do titers measure?

Antibody serum level

What dilution is your titer?

The reciprocal of the largest dilution with response (ex: 1/160)

How do we know if there is an active infection with titers?

there will be a 4 fold increase in 2-4 weeks

What does a positive growth culture indicate?

Something grew, how much qualitatively

What does a negative growth culture indicate?

Nothing grew but is that true or were there transport errors? Special growth conditions needed? Previous antibiotic use?

What is MALDI-TOF?

Mass spec

What is useful about microscopic analysis of bacteria?

Can find morphologic characteristics and general number. Cost effective

What is not useful about microscopic analysis of bacteria?

Low sensitivity and low specificity

What is an example of pathogen-level control?

Washing hands

Define sterilization

eliminates pathogens and endospores

Define disinfection

eliminates pathogens but not endospores

Define decontamination

reduces pathogen-level to be safe to handle

Define antisepsis

Elimination on pathogens on living tissue

What is an example of host-level pathogen control?

vaccinations

What are passive vaccination?

antibodies

What are active vaccinations?

components of a pathogen

What is environmental control of pathogens?

their transmission modes such as water, food, soil

What is an antimicrobial?

destroys or prevents microbes (made from any source)

What is an antibiotic?

A type of antimicrobial made by a living organism

Define bacteriostatic

inhibits the growth of bacteria

Define bacterocidal

Kills bacteria

What is meant by a broad spectrum antimicrobial?

It works against gram positive and gram negative bacteria

What is meant by a narrow spectrum antimicrobial?

only works against gram positive OR gram negative bacteria

What is an example of a narrow spectrum antimicrobial?

penicillin

What is meant by non-therapeutic use of antibiotics?

used for a non-active infection

What are a few examples of non-therapeutic uses of antibiotics?

growth promotion, prophylaxis (prevention), metaphylatic (control)

What are examples of prophylactic antibiotic use?

before surgery, before travel, dry-cow

How do sulfa drugs work?

inhibit folic acid synthesis

Are sulfa drugs broad or narrow spectrum?

Broad

What antimicrobials are broad spectrum?

sulfa drugs, macrolides, fluoroquinolones, aminoglycosides, tetracyclines

Which antimicrobials are bacteriostatic?

sulfa drugs, macrolides, tetracyclines

Which antimicrobials are bacteriocidal?

Fluoroquinolones, aminoglycosides, Beta lactams

Are sulfa drugs bacteriostatic or bacteriocidal?

bacteriostatic

What are sulfa drug synergistic with?

diaminopyrimidines

What is an example of a sulfa drug?

sulphonamide

What are some adverse effects of sulfa drugs?

allergy, keraconjuctivitis

How do macrolides work?

inhibit protein synthesis

What spectrum are macrolides?

Broad

Macrolides bacterio______?

bacteriostatic

What is special about macrolides?

They accumulate in phagocytes

What are examples of macrolides?

erythromycin, azithromycin, clarithromycin

How do fluoroquinolones work?

inhibit DNA gyrase to inhibit replication

What spectrum are fluoroquinolones?

broad spectrum

Fuoroquinolones are bacterio_____?

bacteriocidal

Which antimicrobials are concentration dependent?

Fluoroquinolones and aminoglycosides

What antimicrobials are time-dependent?

Beta lactam and tetracyclines

What is special about fluorquinolones?

Synthetic and rapid resistance development

What are examples of fluoroquinolones?

enrofloxicin and ciprofloxacin

What are some adverse effects of fluoroquinolones?

Arthropathy, ocular toxicity in cats

How do aminoglycosides work?

Inhibit protein synthesis

What spectrum are aminoglycosides?

broad spectrum

Aminoglycosides are bacterio____?

bactericidal

Aminoglycosides are concentration dependent but they are also what?

Oxygen dependent so not good for anaerobic infections

What is unique about aminoglycosides?

No oral options

What are aminoglycosides synergistic with?

B lactams but not physically so require two syringes

What are some examples of aminoglycosides?

gentamicin, tobrmycin, amikacin

What are some adverse effects of aminoglycosides?

nephrotoxicity, oxotoxicity

How do tetracyclines work?

inhibit protein synthesis

What spectrum are tetracyclines?

Broad spectrum

Tetracyclines are bacterio____?

Bacteriostatic

What are examples of tetracylclines?

oxytetracycline, doxycycline, minocycline

What are some adverse effects of tetracyclines?

Cardiovascular, tooth discoloration, GI upset, nephrotoxicity