Control of Microbial Growth and Pathogenicity

These flashcards cover the key concepts related to control of microbial growth and pathogenicity, including sterilization methods, pathogen behavior, virulence factors, and resistance mechanisms.

Moist heat

Used for sterilizing viruses, fungi, and bacteria.

Steam sterilization

Effective against endospores.

Filtration

Used to sterilize heat-sensitive materials like vitamins, antibiotics, and filtering air.

Pasteurization

A method used for liquid products like milk, and beer, to kill pathogenic microorganisms.

Ionizing radiation

Used to sterilize disposable supplies, sutures, and food.

ionizing radiation and sterilizing gases

What method(s) of sterilization would be used to sterilize plastic pipets

causes thymine dimers preventing replication and transcription, can also make cuts in the DNA

How does UV light affect the bacterial cell

Alcohol

Can kill fungi, bacteria, and inactivate some viruses by denaturing proteins and dissolving membrane lipids.

Glutaraldehyde

Cross-links with proteins, thereby inactivating microbes.

Iodophore

Iodine complexed with an organic carrier, released slowly to reduce skin burns.

Chlorine

Used to destroy vegetative bacteria and fungi, commonly for disinfecting water supplies.

Betapropiolactone (BPL)

Used for sterilizing blood products and vaccines.

vaporized hydrogen peroxide

Used for sterilizing operating rooms

Silver nitrate

An antimicrobial agent used for treating burn victims and preventing gonorrhea in newborns.

the evaluation of antimicrobial agent effectiveness

regulated by the epa and fda

Phenol coefficient

Measures the effectiveness of a chemical in killing organisms compared to phenol.

phenol coefficient > 1

chemical is more effective than phenol

phenol coefficient < 1

chemical is less effective than phenol

Primary pathogen

Causes disease in a healthy host (e.g., Bacillus anthracis).

Opportunistic pathogen

Causes disease when the host is immunocompromised (e.g., Pseudomonas aeruginosa).

1. number of organisms present

2. the degree of virulence of Pathogen

3. host's defenses or degree of resistance

factors that affect host-parasite outcome

Incubation period

Time post-pathogen entry before symptoms appear.

Prodromal stage

Onset of vague symptoms prior to confirmed diagnosis.

Period of illness

Stage when disease is most severe.

Convalescence

Recovery period when signs and symptoms start to disappear.

Source

Location from which a pathogen is transmitted.

Reservoir

Natural environment where a pathogen normally lives.

incubatory carrier

incubating the pathogen in large numbers , but is not yet ill

active carrier

has overt clinical case of the disease

convalescent carrier

has recovered but continues to harbor large numbers of pathogen

healthy carrier

harbors the pathogen but is not ill

Extracellular pathogens

Grow outside host cells.

Intracellular pathogens

Multipy within host cells, including facultative and obligate pathogens.

facultative intracellular pathogen

grows within or outside cells

obligate intracellular pathogen

only grows when inside cells

Virulence factors

Components that allow pathogens to cause disease.

Pathogenicity islands

Segments of DNA within pathogens that encode virulence factors.

Invasiveness

The ability of a pathogen to spread through tissues.

Infectious dose 50 (ID50)

The number of pathogens needed to infect 50% of a population.

pili, fimbriae, specialized adhesion molecules

virulence factors involved in adhesion

virulence factors involved in invasiveness

adhesions, invasion enzymes, capsules

Exotoxins

Toxins secreted from bacteria that can cause damage.

Endotoxins

Toxins that are part of the gram-negative bacterial cell wall.

Antimicrobial resistance

Resistance of bacteria to antimicrobial drugs, often due to over-prescription and misuse.

MRSA (Methicillin-resistant Staphylococcus aureus)

Bacteria resistant to many antibiotics due to the production of beta-lactamases.

Tetracycline

b. Protein synthesis inhibitor

Penicillin

a. Cell wall synthesis inhibitor

Bacitracin

a. Cell wall synthesis inhibitor

Ciprofloxacin

c. Nucleic acid synthesis inhibitor (specifically DNA gyrase inhibition)

Rifampin

c. Nucleic acid synthesis inhibitor (inhibits RNA polymerase)

Polymyxin B

e. Plasma membrane disruptor

Chloramphenicol

b. Protein synthesis inhibitor

Ampicillin

a. Cell wall synthesis inhibitor

Sulfa drugs (Sulfonamides)

d. Inhibit essential metabolites