MLT 101: Microbiology Lecture Notes

This set of flashcards covers key vocabulary and concepts from the microbiology lecture notes, including definitions of various types of microorganisms, biosafety levels, culturing techniques, and methods for identifying pathogens.

Normal flora

Organisms, Microorganisms, and germs that do not cause disease but work very hard to keep us healthy inside our bodies

Pathogenic microorganisms

Microorganisms that cause disease

Nonsocomial Infection

An infection or disease acquired in the hospital more than 24 hours. after admission, taking into consideration the incubation period of the disease

The proper way to write the name of bacterium

Genus is capitalized, and species are lowercased, both italicized. If not able to italicize them, I must underline them

Biosafety level 1

Biological agents that do not usually cause disease or harm to the body

Biosafety level 2

Biological agents typically handled in routine microbiology labs that can be suppressed by antibiotics

Biosafety level 3

Biological agents that must be handled in a biological safety cabinet. Most are agents of bioterrorism such as Microbacterial Tuberculosis

Biosafety level 4

Highly controlled microorganisms with a significant risk of aerosol transmission such as Small Pox and HIV

A good disinfectant to use on countertops

Bleach diluted to 10% (1:10 dilution)

The two means of Sterilization

1. Flame to bake for 1 hour 2. Steam for 15 minutes

Sterilization by dry heat

Process requiring 171°C for 1 hour.

Sterilization by moist heat

Typically performed in an autoclave at 121°C steam for 15 minutes.

The 8 several acceptable specimens for culture

Urine, Stool, CSF, Tissue, Blood, Peritineal, Swabs, Sputums, Sweat

The two types of media we may use to recover bacteria from a specimen (or grow it)

Solid and Liquid broth (Auger or Jello kind of liquid)

The temperature required for bacteria and fungus to grow in their mediums

35-37 degrees C, 42 degrees C for Campylobacteria

The two common morphologies encountered in bacteria

1. Coccus/Cocci (Round/spherical) 2. Bacillus “rods” (Long round like rice)

The first step to the Gram Stain Technique

The bacterial smear should be fixative-well dried and heat fixed; then crystal violet dye is added

Step 2 of the Gram Stain Technique

Add Gram’s iodine

Step 3 of the Gram Stain Technique

Add Decolorizer for both grams (either acetone or alcohol). Gram-positive’s color will not wash off, while Gram-negatives will

Step 4 of Gram Stain Technique

Add Safranin counterstain. Gram-positives will remain purple while Gram-negatives will be stained pink

Gram stain

A differential stain used to classify bacteria as Gram-positive or Gram-negative.

Cocci

Spherical-shaped bacteria that can appear in clusters, chains, pairs, or tetrads.

Bacilli

Rod-shaped bacteria

The color of a Gram-Positive bacteria or organism

Purple

The color of a Gram-Negative bacteria or organism

Pink

The 3 patterns of hemolysis seen

1. Gamma -No Hemolysis 2. Apha-Partial hemolysis; Green color 3. Beta-Complete hemolysis; Yellow color due to bilirubin

Media always used for hemolytic organisms

Sheep blood (5% of this is usually added to a solid media)

Examples of normal flora

Staphylococcus epidermidis, Cutibacterium acnes, Lactobacillis spp.

Opportunistic bacteria or flora

Bacteria or others that don’t typically harm the body but excess of antibiotics and a poor immune system can make them become opportunistic pathogens

Example of an opportunistic pathogen

E. coli (Escherichia coli)