Microbiology: Fundamentals

Robert Hooke

cell theory

Anton van Leuwenhoek

examined living specimen (sperm cell) under microscope and called them “animalcules'“

spontaneous generation

molecules were believed to spontaneously appear from nothing

John Needham

spontaneous generation proponent

Francesco Redi

Lazzaro

Spallanzani

spontaneous generation opponents

Biogenesis theory

living cells came from pre-existing cells

Rudolf Virchow (no evidence)

proposed Biogenesis theory

pasteurization

mild heat treatment for food, most notably milk, that kills pathogenic microorganisms

MaSuSo

Mycobacterium bovis

Salmonella spp

Streptococcus spp

milk-borne pathogens

63C for 30 mins

Pasteurization

• home

72C for 15 mins

Pasteurization

• high temp, short time

140C for 4 secs; common in milk

Pasteurization

• ultrahigh temp (UHT)

fermentation

anaerobic conversion of sugar to simple substances

2 lactic acid

homolactic fermentation produces

lactic acid, CO2, ethanol

heterolactic acid fermentation produces

SPA

Swan neck/Gooseneck flask exp

Pasteurization

Anaerobic process

Louis Pasteur discovered:

Tyndallization

intermittent/fractional sterilization

Tyndallization

John Tyndall discovered

Paul Ehrlich

Father of antimicrobial chemotherapy

Paul Ehrlich

discovered Salvarsan

compound 606, arsphenamine, magic bullet

salarsan other names (3)

Treponema pallidum (syphilis)

salvarsan has activity against the bacteria _______

Alexander Fleming

discovered penicillin

Florey and Chain

isolated penicillin

Viridans streptococcus

bacterial residents in oral cavity

BBEL

Bacteroides spp.

Bifidobacterium spp.

E. coli

Lactobacillus spp.

bacterial residents in colon/large intestine

Lactobacillus spp.

bacterial residents in urethra

Staphylococcus epidermidis

bacterial residents on skin

mouth/oral cavity (PACOP ans)

largest popu of normal flora

Salmonela typhi

causative agent of salmonellosis and typhoid fever

salmonellosis

diarrhea from poultry (chicken and egg)

Mycobacterium leprae

causative agent of Leprosy

Mycobacterium leprae (leprosy)

causative agent of Hansen’s disease

(+) bacteria in normal flora

carriers: (+) organism, (-) disease

Mycobacterium leprae: never grown in pure culture

3 considerations in Koch’s postulates

Mycobacterium leprae

requires armadillo, mouse footpad to be grown

mitochondria

primary site of ETC

prokaryotes: 70S (30S, 50S)

eukaryotes: 80S (40S, 60S)

ribosome subunits of prokaryotes vs eukaryotes

archaebacteria

methanogen

dinoflagellates

red tide poisoning

bacterial: peptidoglycan

fungi: chitin

human: none

composition of bacterial, fungi and human cell wall

bacteria: none

fungi: ergosterol

human: cholesterol

composition of bacterial, fungi and human cell membrane

generation time

time it takes for microbes to double the population

Stage 1: Lag Phase

Stage of Microbial Growth

• capable of metabolism

• no reproduction

Lag Phase

Log Phase

Stationary Phase

Decline Phase

Stages of Microbial Growth

Stage 2: Log Phase

Stage of Microbial Growth

• exponential phase

• (+) reproduction

Stage 2: Log phase

Stage of Microbial Growth

• target of bactericidal agents

Stage 3: Stationary Phase

Stage of Microbial Growth

• balanced growth

Stage 4: Decline phase

Stage of Microbial Growth

• decrease of resources required for survival

physical reqs, food, oxygen

3 requirements for microbial growth

TOP

Temperature

Osmotic pressure

pH 6.5 to 7.5 (pH 5.5 to 6.5 for fungi, slightly acidic)

physical reqs for microbial growth

psychro/cryophile

cold-loving microbes

mesophile

microbes that prefer moderate temp

thermophile

heat-loving microbes

proteins, carbohydrates, fats

3 primary essential nutrients

PaMaNiLa

Pseudomonas

Mycobacterium

Nocardia

Leptospira

(and other lung infxn-causing bacteria)

obligate aerobes

ABC

Actinomyces

Bacteroides

Clostridium

obligate anaerobes

E. coli

facultative anaerobe

LP

Lactobacillus

Propionibacterium

aerotolerant anaerobe

Spirochetes (Lugaw, Tokwa’t Baboy)

EXCEPT Leptospira

Treponema

Borrelia

microaerophile

Ignaz Semmelweiss

importance of handwashing

Ignaz Semmelweiss

dubbed as savior of mothers

handwashing

most important intervention to prevent nosocomial infxn

phenol/carbolic acid

previously the #1 method of chemical control

Joseph Lister

father of antiseptic surgery (phenol/carbolic acid)

Phenol coefficient

parameter to compare phenol vs new chemical in killing bacteria

Salmonella typhi, Staphylococcus aureus

phenol coefficient test organisms

degerming

mechanical removal of organisms (e.g. alcohol swabbing)

PussyCat Dolls

Popu size

Concentration

Duration of use

disinfectant effectiveness is influenced by

iodine (povidone-iodine)

#1 skin antiseptic

chlorine

disinfectant of choice in municipal water supply

chlorine

(+) hypochlorous acidc

sterilization

complete removal of all microorgs; kill spore and vegetative form

disinfection

alive spore, kill vegetative form

antiseptic

for animate object

disinfectant

for inanimate object

heat, filtration, canning, radiation

Physical control (4)

protein denaturation

heat results in

autoclave

moist heat

autoclave

MOA: heat, coagulation of protein

autoclave

121C, 15 psi at 15-20 mins

Bacillus stearopothermophilus

moist heat (autoclave) bacterial indicator

OK

OK or NOT OK?

most heat for water, glassware, culture medium

NOT OK

OK or NOT OK?

moist heat for olive oil, solvents

oven

dry heat

oven

MOA: heat, oxidation

Bacillus subtilis

oven bacterial indicator

filtration

physical control for heat sensitive

membrane filter

FILTRATION

pore size: 0.2 mcm

HEPA Filter

FILTRATION

removes >0.3 mcm

penicillin

vaccine

enzyme soln

membrane filters may be used for (3)

no O2 inside cans —> prevent growth of aerobes (PaMaNiLa)

how does canning allow physical control

heating step

how is anerobic growth prevented in canning

DNA

radiation targets

xray, gamma

ionizing radiation

uv

non-ionizing radiation

ionizing radiation

MOA: split molecules and drive electrons away

non-ionizing radiation

MOA: leads to formation of thyminedimer

denaturation

alcohol MOA

ethanol

more volatile

ethanol vs isopropyl alc

70% (to allow denaturation, requires water)

conc of alcohol is capped at