Introductory Microbiology 1-6 VOCAB

Serology

the study of blood serum

Immunology

the study of the body’s defense against specific pathogens

Chemotherapy

Treatment that uses drugs to stop the growth of cancer cells, either by killing the cells or by stopping them from dividing.

Light Microscope/Scanning

a microscope that allows differential colors to be seen and often used when gram staining

Transmission Electron Microscope

a microscope that is used to see density

• shows a lot of detail because of high magnifiiciation

Scanning Electron Microscope

a microscope that shows electrons bounced off a specimen and only shows surface features

• often appear 3D

Strain

A variant of a plant, virus or bacterium; or an inbred animal used for experimental purposes

Serovar (or serotype)

group of microorganisms classified together based on their cell surface antigens.

Catabolism

Degradation of organic molecules to provide energy (ATP source)

• Also provides building blocks

Anabolism

Synthesis of larger organic molecules from smaller ones

• requires energy

Autotroph

self-feeding

• Use CO2 as C source, non-organic source for energy

• photosynthesis by plants and some bacteria

Heterotroph

other-feeding

• Preformed organics (sugars, protein, fat) used as C source & energy

Fastidious

difficult to feed

• Require extra nutritional supplements (more that those in ordinary BHI medium) to grow

• Eg. Blood-loving bacteria Haemophilus influenza grows on blood agar

Cellular Respiration

The process in which nutrients are converted into usable energy

Glycolysis

glucose to pyruvate

Krebs Cycle (TCA cycle)

Uses C in pyruvate to go around the cycle, make ATP, CO2, and lots of electrons (e-).

Electron transport chain

The e- feed into the e- transport chain, pump out protons to make a gradient, as protons return into cell they are coupled to make up to 34 ATP. Requires Oxygen (depending on conditions)

Obligate aerobic

bacteria gather at the top of the test tube in order to absorb maximal amount of oxygen.

Obligate anaerobic

bacteria gather at the bottom to avoid oxygen.

Facultative anaerobic

primarily aerobic and alternatively anaerobic, in other words they can grow with or without oxygen, but preferentially grow with oxygen. bacteria gather all along the test tube, since the lack of oxygen does not hurt them.

Microaerophiles

require oxygen but at a low concentration. They gather at the upper part of the test tube but not at the top.

Aerotolerant anaerobes

do not utilize oxygen, and are not affected by it. bacteria are not affected at all by oxygen, and they are evenly spread along the test tube.

Superoxide dismutase (SOD)

Enzyme which reacts the harmful free radical to form the Hydrogen Peroxide radical (also harmful, but less so than O2-)

Catalase and Glutathione Peroxidase (GPx)

Enzyme which reacts hydrogen peroxide to render the free radical harmless

Psychrophile

[– 15⁰ C ~ 5⁰ F] Food on your refrigerator

Mesophile

[37⁰ C ~ 98.6⁰ F]

Thermophile

[ 60⁰ C ~ 140⁰ F]

Extreme thermophile

[ >100⁰ C ~ 212⁰ F]

Acidophile

low pH (high acid), <5 sour

Neutrophile

neutral pH, ~6-8

Alkalophile

high pH, >8 bitter

Antibiotic

against living organism

Narrow spectrum

effective against only a limited range of organisms

Eg. Penicillin is effective against mostly Gram (+) bacteria

Broad spectrum

refers to an antibiotic with activity against a wide range of organisms

Eg. Amoxicillin is effective against both Gram (+) and Gram (-) bacteria

Bactericidal (Cidal)

Drug that completely destroys bacteria

– Eg.- Cell Wall antibiotics like Penicillin (in family of Beta-lactams)

• work by irreversible binding to active site of enzymes that link peptidoglycan

molecules (transpeptidases)

Bacteriostatic (static)

Drug which stops cell growth

– Eg. Erythromycin

• Drug binds to subunits of bacterial ribosomes and stops bacterial protein synthesis which then stops growth of bacteria without destroying them

Semisynthetic

A molecule derived from a biological source and manipulated in the laboratory to improve characteristics

Selective toxicity

Toxic to one thing but not another.

– A good antibacterial drug should be highly toxic to bacteria but non-toxic,

or very little toxicity to humans

Unique target

Basis for selective toxicity

– A site in pathogen that is infecting the patient that drug needs to work

specifically that is not present in the patient

– Example, penicillin targets peptidoglycan (PG) which is present in bacteria

only

– A reason we need to compare prokaryotes (bacteria) and eukaryotes

(human) in detail

Prophylaxis

Preventative measures

– Example, if a patient has a history of rheumatic fever, you would treat

prophylactically with antibiotics before a dental or surgical procedure

Spontaneous mutation

extremely rare event which occurs as a result of natural processes in cells (eg. mistakes in DNA replication)

Induced mutations

occur more frequently as a result of interaction of DNA with a mutagen (an outside agent that induces mutation)

Mutagens

natural or human-made (physical or chemical) agents that change the genome (DNA) of an organism

Transformation

the process by which bacterial cells take up naked DNA molecules and incorporate it to their own DNA

– Example, Griffith’s experiment S. Pneumoniae production of capsule

• low efficiency of gene transfer

Conjugation (nonconventional bacterial sex)

genetic material (usually a plasmid) is transferred from a donor bacterium to a recipient bacterium through direct cell-to-cell contact.

Transduction (by bacteriophage)

mechanism of horizontal gene transfer where bacterial DNA is mistakenly packaged into a virus particle and transferred to another bacterium

Plasmids

A small, circular molecules of DNA that is separate from the bacterial chromosome. The size of a plasmid ranges from 3% to 20% of the size of the

bacterial chromosome

R-factors

A plasmid that carries R (resistance) gene for antibiotics and gives the bacterium the ability to resist many antibiotics

Contamination

the mere presence of microbes in or on the body

Infection

results when the organism has evaded the body’s external defenses, multiplied, and become established in the body

• the invasion of the host by a pathogen

Disease (morbidity)

results only if the invading pathogen alters the normal functions of the body

Symptoms

subjective characteristics of disease felt only by the patient: eg. headache, backache

Signs

objective manifestations of disease that can be observed or measured by others: eg. fever, chills, rash

Syndrome

group of symptoms and signs that characterize a disease or abnormal condition: eg. Severe acute respiratory syndrome (SARS)

Asymptomatic / Subclinical

infections lack symptoms but may still have signs of infection

Pathogenicity

ability of a microorganism to cause disease

Virulence

degree of pathogenicity

Endotoxins

(LPS) in the outer membrane of Gram-negative bacteria, released upon cell death, heat-stable, and cause general symptoms like fever (sepsis)

Exotoxins

proteins secreted by living bacteria (both Gram-positive and some Gram-negative), are heat-labile, highly specific, and can be neutralized into toxoids for vaccines

Animal reservoir: Zoonotic

diseases that are naturally spread from their usual animal host to humans

Human Carriers

Infected individuals who are asymptomatic but infective to others

Nonliving Reservoirs

Soil, water, and food can be reservoirs of infection

– Presence of microorganisms is often due to contamination by feces or urine

Contact transmission

direct: handshaking

indirect: drinking glasses

droplet transmission: sneezing

Vehicle transmission

airborne: dust particles

waterborne: swimming pools

foodborn: poultry

Vector transmission

mechanical: (carried on insects) flies

biological: mosquitoes

Epidemiology

Study of where and when diseases occur and how they are transmitted within populations

Incidence

number of new cases of a disease in a given area during a given period of time

Prevalence

number of total cases of a disease in a given area during a given period of time

Endemic

A disease that exists permanently in a particular region or population. Malaria is a constant worry in parts of Africa.

Sporadic

A disease that occurs only occasionally in a population (prevalence is close to zero).

Epidemic

Occurs when new cases of infection exceed substantially what is normally expected in a population

Pandemic

When an epidemic spreads throughout the world.

Exogenous

pathogen acquired from the health care environment

– eg. Getting MRSA at an ICU

Endogenous

pathogen arise from normal microbiota due to factors within the health care setting.

Examples: Getting UTI with catheters

Iatrogenic

Caused by avoidable medical actions

• eg. Infection following routine surgery