Microbiology Intro

Microbiology

The study of microorganisms, a large and diverse group of microscopic organisms that exist as single cells or cell clusters.

Microorganisms

Most microbes are unicellular and small enough that they require artificial magnification to be seen
Some unicellular microbes are visible to the naked eye
Some multicellular organisms are microscopic
Some (like viruses) are acellular

Types of microorganisms

Microorganisms differ from each other in size, structure, habitat, metabolism, and many other characteristics

Prions

Protein particles that do not contain any genetic information

Microorganisms domains of life

Archaea, Bacteria, and Eukarya

Penicillin

Discovered by Alexander Fleming in 1928 as the first antibiotic, made by the Penicillium fungus that killed S. aureus

Scientific nomenclature

The Genus and specific epithet, italicized or underlined
Established by Carolus Linnaeus in 1735

Binary fission

A mode of replication where one parent cell divides to make two progeny cells while retaining its cellular structure (done by prokaryotic cells)

Mitosis

A process of cell replication where one parent cell divides to produce two identical daughter cells (done by eukaryotic cells)

Viruses

Disassemble, produce many copies of their nucleic acid and protein, and then reassemble into multiple progeny viruses (contain only either DNA or RNA)

Eukaryotic cells

Cells that contain both DNA and RNA and have a mitotic spindle formation during mitosis

Prokaryotic cells

Cells that do not have a nucleus and do not undergo mitotic spindle formation during binary fission

Eukaryotic cell membranes

The made of phospholipid bilayer, is selectively permeable, and may have different proteins depending on type of cell

Selective permeability

A characteristic of eukaryotic cell membranes that allows certain substances to pass while blocking others

1970s BINOculars

70S ribosomes, binary fission, no nucleus or membrane bound organelles

Serendipity

The occurrence of making fortunate discoveries by accident, like the discovery of penicillin

Alexander Fleming

The bacteriologist who discovered penicillin in 1928

Antibiotics

Substances that kill or inhibit the growth of bacteria, with penicillin being the first discovered

Gram staining technique

A method used to differentiate bacterial species into two groups based on the characteristics of their cell walls

Origin of penicillin

Contamination of culture plate of staphylococci by mould

Eukarya

One of the three domains of life that includes organisms with eukaryotic cells

Bacteria

One of the three domains of life, consisting of unicellular organisms that lack a nucleus

Archaea

One of the three domains of life, consisting of unicellular organisms that are distinct from bacteria

Nucleus

Where DNA is stored in eukaryotic cells

Cytoplasm

The jelly-like substance within a cell where organelles are suspended

Bacteriology

The study of bacteria

Mycology

The study of fungi

Virology

The study of viruses

Parasitology

The study of protozoa and parasitic worms

Genomics

The study of an organism's genes

Pathogenic bacteria

Bacteria that are known to cause disease

Gram-positive bacteria

Bacteria with a thick, mesh-like layer of peptidoglycan in their cell walls that retain crystal violet dye

Gram-negative bacteria

Bacteria with a thin layer of peptidoglycan and an outer membrane containing lipopolysaccharides

Peptidoglycan

A large polymer made up of sugars and amino acids, unique to bacteria

Endotoxins

Also known as lipopolysaccharides, found in the outer membranes of gram-negative bacteria

Non-pathogens

Bacteria that do not cause disease

Epidemics

Widespread occurrences of infectious diseases in a community

Food Spoilage

The process of food becoming unsuitable for consumption due to microbial growth

Human body bacteria

The human body is composed of approximately 10 times the number of bacteria cells than human cells

Crystal violet dye

A dye used in the Gram staining method that stains gram-positive bacteria violet

Decolorizing process

The process in the Gram staining method where gram-negative bacteria do not retain crystal violet dye

Outer membrane

A membrane found in gram-negative bacteria that is not present in gram-positive bacteria

Staphylococcus aureus

Pathogen transmitted through direct contact, contaminated surfaces, and nasal carriers, mnemonic: 'Staff stay on your skin'.

Streptococcus pyogenes

Pathogen transmitted via respiratory droplets and direct contact, mnemonic: 'Pyro = fire throat'.

Streptococcus pneumoniae

Pathogen transmitted through respiratory droplets, mnemonic: 'New-moan-ia from the street'.

Enterococcus faecalis/faecium

Pathogen transmitted via fecal-oral route and contaminated hands/equipment, mnemonic: 'Entero = gut guest'.

Bacillus anthracis

Pathogen transmitted through cutaneous contact, inhalation, and ingestion of spores, mnemonic: 'Black anthrax letters'.

Clostridium tetani

Pathogen transmitted through spores in soil entering wounds, mnemonic: 'Rusty nail tango'.

Clostridium botulinum

Pathogen transmitted through preformed toxin in canned foods, wounds, and infant gut, mnemonic: 'Botox in a can'.

Clostridium difficile

Pathogen transmitted via fecal-oral route through spores, often post-antibiotic, mnemonic: 'Difficult diarrhea'.

Listeria monocytogenes

Pathogen transmitted through contaminated cold foods and vertically from mother to fetus, mnemonic: 'Listeria likes the fridge'.

Neisseria meningitidis

Pathogen transmitted through respiratory droplets, mnemonic: 'MEN in meningitidis → mouth to mouth → respiratory'.

Neisseria gonorrhoeae

Pathogen transmitted through sexual contact and vertically, mnemonic: 'GO in gonorrhoeae → go south'.

Escherichia coli

Pathogen transmitted via fecal-oral route, food/water, and contact, mnemonic: 'Eat contaminated lettuce'.

Salmonella enterica

Pathogen transmitted through contaminated poultry/eggs and reptiles, mnemonic: 'Salmon sandwich'.

Shigella spp.

Pathogen transmitted via fecal-oral route with a low dose, mnemonic: 'Shhh! It's in the salad'.

Vibrio cholerae

Pathogen transmitted via fecal-oral route through water/seafood, mnemonic: 'Rice-water from rivers'.

Yersinia pestis

Pathogen transmitted through flea bites (rodents) and droplets, mnemonic: 'Yersinia's fleas'.

Pseudomonas aeruginosa

Pathogen transmitted through water, moist hospital equipment, and wounds, mnemonic: 'Pseudo swims'.

Mycobacterium tuberculosis

Pathogen transmitted via airborne droplets, mnemonic: 'Tuber-cough-losis'.

Mycobacterium leprae

Pathogen transmitted through prolonged contact and nasal droplets, mnemonic: 'Leper's long contact'.

Treponema pallidum

Pathogen transmitted through sexual contact and vertically, mnemonic: 'Trip with Treponema'.

Borrelia burgdorferi

Pathogen transmitted through Ixodes tick bite, mnemonic: 'Borrelia = forest tick'.

Leptospira interrogans

Pathogen transmitted through water with animal urine, mnemonic: 'Leptos from puddles'.

Chlamydia trachomatis

Pathogen transmitted through sexual contact and vertically, mnemonic: 'Chlamydia traps you'.

Rickettsia rickettsii

Pathogen transmitted through tick bite, mnemonic: 'Rocky rickety tick'.

Probiotics

Good bacteria that provide health benefits, including Lactobacillus and Bifidobacterial species

Immunity

The body's inherent ability to protect against infections.

Aerobic bacteria

Require oxygen

Anaerobic bacteria

Do not require oxygen

Obligate

Cannot survive (aerobic) without oxygen or (anaerobic) with oxygen

Microaerophilic

Require lower concentration of oxygen (<21%)

Facultative anaerobic

Can grow without oxygen but use it if present

Aerotolerant

Cannot use oxygen for growth but are not harmed by it

Opportunistic

Can produce disease when immunity goes down

Benefits of bacteria

Primary decomposers, produce various food products (cheese, yogurt, beer)

Viruses

Consist of nucleic acid molecule (DNA or RNA) and protein coat (capsid)
Lack attributes of cells such as ability to replicate

DNA virus vs RNA virus

DNA: contain large genomes (accurate replication), most double stranded
RNA: contain small genomes (error-prone replication), most single stranded

DNA virus examples

Hepadnaviruses
Herpesviruses
Adenoviruses
Poxviruses
Parvoviruses
Papovaviruses
(HHAPPy)

RNA virus examples

only- orthomyxoviruses
rude- reoviruses, rhabdoviruses, retroviruses
teacher- togaviruses
can- coronaviruses
punish- picornaviruses, paramyxoviruses
all- arenaviruses
fighting- filoviruses, flaviviruses
bullies- bunyaviruses

Viral diseases examples

Small pox, chicken pox, measles, poliomyelitis, influenza, rabies, mumps, AIDS, common cold, respiratory infections

Fungi

Variation in size, well defined cell wall of polysaccharides, important in immunocompromised patients and increased use of antibiotics

Fungi causing CNS infection

Cryptococcus
Histoplasma
Coccidiomycosis
Candida
Aspergillus
Blastomycosis
Sporothrix shenkei
(CHC CAB)

Parasites

Animal kingdom

Parasite examples

Spiromerta sp
Plasmodium sp
Echinococcus granulosus
Echinococcus multilocularis
Taenia multiceps
(SPEET)

Parasites- intestinal entry

Disease everywhere, acquired toxoplasmosis
hydatid disease (echinococcus)
cysticercosis (taenia solium)
visceral larva migrans (Toxocara canis)
trichinosis (trichinella spiralis)

Parasites- skin entry

Intestinal manifestations
Hookworm
Strongyloides
Schistosoma mansoni

Gram positive vs Gram negative

NO poLlEN
negative=LPS=endotoxins

Gram positive cocci

LoVE is Positive
Lactococci
Staphylococci
Streptococci
Viridians
Enterococci

Gram negative cocci

Neisseria

Gram positive bacilli

cute Lady names ABC is positive
Actinomyces
Bacillus
Clostridium
Corynebacterium
Listeria

Gram negative bacilli

SalmonELLA
Shigella
Legionella
Klebsiella
Bordetella
Brucella
Francisella
Pasteurella

Gram positive bacilli- MACDONALD

Mycobacterium species

Anthracis bacillus

Clostridium species

Diptherial corynebacterium

O

Nocaridia

Actinomyces

Listeria

Diptheroids

Anaerobic examples

anaerobes Can’t Breath Fresh Air

Clostridium

Bacteroids

Fusobacterium

Actinomyces israelii

Aerobic examples

Nagging Pest Must Breathe

Nocardia

Psuedomonas

Mycobacterium tuberculosis

Bacillus anthracis

Capnophile

High carbon dioxide loving

Facultative aerobic examples

BPH

Brucella abortus

Pneumococcus

Haemophilus influenza

Bacteria temperature classifications

Psychrophile: -20c to 15c

Mesophile: 20c to 40c

Thermophile: more than 60c