Bacteria for microbio

How bacteria is grouped

How bacteria is grouped

morphology, staining reactions, presence of endospores, biochemical reactions, molecular biology techniques, similarity at molecular level (r-RNA)

Rickettsia

obligate intracellular parasites- have to infect a cell to grow very much like viruses

Shape of rickettsia

gram negative rods

How is rickettsia transmitted

insect and tick bites, vectors; lice, ticks,

Illness rickettsia causes in humans

causes spotted fevers in humans, looks like blood under the skin

Rickettsia rickettsia

rocky mountain spotted fever

Wolbachia

most common infectious bacterial genus in the world and is gram negative rod

What does Wolbachia infect

lives inside insects and invertebrates and can turn male insects into females

Burkholderia shape

gram negative motile rods previously grouped with pseudomonas

Burkholderia cepacia

most common species that contaminates equipment in hospitals and mainly causes infections in cystic fibrosis patients

Bordetella shape

encapsulated gram negative rod

Bordetella pertussis

gram negative coccobacillus, encapsulated

it is very contagious with 2000 cases a year in USA

Virulence factors of B. pertussis

pertussis toxin

tracheal cytotoxin

pili

endotoxin

pertussis toxin (exotoxin)

inhibits monocyte migration to infection

tracheal cytotoxin (exotoxin)

inhibits action of cell cilia; kills ciliated epithelial cells, accumulation of mucus

pili

adherence to respiratory tract

How is B. pertussis transmitted

respiratory route

Catarrhal stage

initial stage of pertussis infection, symptoms are sneezing and coughing

Paroxysmal stage

second stage which severe coughing ending in whooping sound as air is inspired and is the most contagious stage

Convalescence stage

third stage where there is less severe coughing

What vaccine is used for pertussis

subunit vaccine now being used, acellular vaccine available for all does DTaP

Tdap

recommended for boosters in adolescents and adults because of waning immunity

Pseudomonas

most medically important pathogen

resistant to many antibiotics and disinfectants

How is pseudomonas resistant

outer membrane contains porins that pump these chemicals outside the cells rapidly and can grow inside disinfectant bottles

What does pseudomonas secrete that helps identify it?

secretes a soluble, blue-green pigment into surrounding media like blue-green puss

Pseudomonas nosocomial infections

causes pneumonia, urinary tract infections, infections in burns

nosocomial infections

found in faucets, showers, syringes, soaps, catheters, and other hospital instruments

Enterobacteriales

facultative anaerobic gram negative rods

characteristics of the enterics

primaryly inhabit the intestinal tracts of humans and animals

some are motile with flagella

some have fimbriae for attachment to cell surfaces

many produce bacteriocins-lyse other enterics

7 important genera of enterics

escherichia

salmonella

shigella

klebsiella

serratia

proteus

yersinia

Escherichia

e.coli is the most common facultative anaerobe in the gut, gram negative rod

why is water and food tested for e. coli

it is an indicator for fecal contamination

What strain of ecoli cause gastroinestinal diseases

e. coli 0157:H7 cause travelers diarrhea and urinary tract infections

Salmonella

gram negative rods most are pathogenic

Where is salmonella found

commonly inhabit the intestinal tract of animals specifically cattle and poultry

What is the most common human pathogen of salmonella

S. enterica where multiple serovars depending on flagellar antigen it causes a variety of food poisonings due to uncooked or undercooked poultry

S. typhi

typhoid fever (most pathogenic) causes serious infection of the intestines that can lead to intestinal mucosal wall perforation

Shigella

gram negative rods

found only in humans

S. Dysenteriae - causes Bacillary Dysentery

Klebsiella

mainly found in soil and water

common in hospitals

k. pneumoniae- pneumonia in immune compromised individuals and A MAJOR PROBLEM IN ANTIBIOTIC RESISTANCE

Serratia

S. Marcescens- hospital acquired (nosocomial) infections

urinary and respiratory tract infections and septicemias

can produce a red pigment

Proteus

very actively motile, swarmer

urinary tract infections that may lead to kidney infections

Yersinia

most important human pathogen is Y. Pestis

bubonic plague

mainly found in rats and squirrels (rodents)

Can be transmitted to humans by direct contact with these animals or with their fleas

Haemophilus

mainly found on mucous membranes of nasopharynx

require blood to grow in culture

blood supplies bacteria with the X & V factors

-X factor heme

-V factor is NAD+

H. Influenzae

pneumonia, ear aches, epiglottitis. NOT THE FLU

most common cause of meningitis in children under 6 years of age

H. Ducreii

Causes a sexually transmitted disease called chancre

Bdellovibrio

not a human pathogen

very interesting because it attacks other gram negative bacteria

penetrates the cell wall and cell membrane, replicates inside causing cell lysis

Chlamydia and Chlamydophila

obligate intracellular parasites

gram negative coccobacilli with a unique life cycle

infective form that enters the cell is the elementary body

changes into larger intracellular form the reticulate body

transmitted by personal contact or respiratory route

Chlamydia Trachomatis

may causes trachoma- blindness in humans and non-gonococcal urethritis (STD)

Chlamydophila psittaci

causes psittacosis (pneumonia from birds) through contact with birds and parrots

Chlamydophila pneumoniae

causes a mild form of pneumonia

Life Cycle of chlamydia’s

the bacterium infectious form the elementary body, attaches to a host cell

the host cell phagocytizes the elementary body, housing it in a vacuole

the elementary body reorganizes to form a reticulate body

the reticulate body divides successively producing multiple reticulate bodies

the reticulate bodies begin to convert back to elementary bodies

the elementary bodies are released from the host cell

Bacteroides

strict anaerobic gram negative rods

non motile, non spore forming

usually inhabit the human oral cavity

most common microorganism in the human intestinal tract

may cause infections in the peritoneum after perforation of the intestines due to surgery, gunshots, or knife wounds

Fusobacterium

long, slender, pointed end rods that are strict anaerobe

mainly found in the human oral cavity gingival crevices

may cause gum disease

Spirochetes

gram negative helical rods

motile via axial filaments

found in soil, decaying matter, contaminated water, in animals/ humans

Human Spirochetes pathogens

treponema pallidum- syphilis

borrelia burgdorferi- lyme disease

Leptospira species- spread by water contaminated with animal urine → leptospirosis

Gram negative spirals

facultative anaerobic gram negative rods that are usually curved

vibrio

campylobacter

helicobacter

Vibrionales

facultative anaerobic gram negative rods that are usually curved

The genera Vibrio

usually have a comma shaped appearance

most important human pathogen is vibrio cholera

vibrio cholerae- cholera

vibrio parahaemolyticus- shellfish food poisoning due to ingesting raw fish and oysters

Campylobacter

small vibrio like organisms found in cattle and sheep

may cause abortions in animals

Campylobacter jejuni

gastroenteritis after ingesting improperly cooked meat and chicken (can survive at 43C)

Helicobacter

helicobacter pylori

Helicobacter Pylori

curved rod that causes gastritis and peptic ulcers in humans

gram negative spiral shaped rod

30-50% of population are infected only 15% develop ulcers

damages the stomach mucosa associated with gastric cancer

causes localized inflammation

leads to immune response which is the ulcerated area

promotes gastric duodenal ulcers probable co factor for stomach cancer

Treatment of Helicobacter pylori

antibiotic (metronidazole) and anti acid drugs

Neisseria

gram negative diplococci

found in human mucous membranes

pathogens are N. Gonorrhea and N. meningitides

Moraxella

shape is gram negative cocci M. lacunata- conjunctivitis (pink eye)

M. catarrhalis- possibly involved in some ear infections (otitis media)

Thiomargarita namibiensis

the largest of all prokaryotes

sulfur pearl of namibia

discovered coast of namibia in very deep waters 1999

gram negative coccus 750 um

gets energy from h2s

discovered largest bacterium on mangrove leaves

Gram positive bacteria

include many rods and cocci that are important human pathogens

mycoplasmatales

epulopiscium

clostridiales

bacillales

lactobacillales

mycoplasmatales

Mycoplasmatales

do not have a cell wall but are gram positive

can be filamentous and are pleomorphic because they lack a cell wall

plasma membrane does contain sterols

filterable and have a fried egg apperance on agar plates

aerobes or facultative aerobes

M. Pneumoniae

primary atypical pneumonia or walking pneumonia

Clostridium

obligate anaerobic, gram positive rods that produce endospores

important in medicine and food industry due to resistance of the endospores

C. Tetani

tetanus

C. botulinum

botulism- severe food posioning

C. perfringes

gas gangrene, food posioning

C. difficile

serious diarrhea after administration of antibiotics

Clostridium tetani

gram positive spore forming anaerobic rod

found in soil, animal, and some human GI tracts

old, dirty, rusting objects

spores enter through cuts/deep puncture wounds and germinate if no oxygen is present

tetanus neonatorum enters through cut stump of umbilical cord

virulence of clostridium tetani

due to presence of plasmid that codes for a neurotoxin called tetanospasmin

symptoms are caused by the neurotoxin since bacteria do not spread in the body

stops nerve impulses at nerve-nerve junctions

inhibits muscle relaxation pathway, muscle spasms → spastic paralysis

Vaccines against C. tetani

DTaP- Diphtheria, pertussis, tetanus

tetanus toxoid- immunogen, boosters every 10 years

also need to administer tetanus immunoglobulin during treatment

Bacillus

includes members that are aerobic gram positive rods that produce endospores

mainly found in soil and some are pathogens of humans and animals

bacillus anthracis- anthrax

disease of cattle that can be transmitted to humans

B. Thuringensis

insect pathogen

used as a vector for recombinant DNA work using insect cell lines

sold as gardening supplies to kill insects on plants

Anthrax

facultative anaerobic spore forming gram positive rod

primarily in farm grazing animals (cattle, sheep) - zoonotic

spores found in soil up to 60 years

Transmission

handling animal product → skin abrasions; eating meats infected flesh; inhalation of spores

hides hair, furs, animal products, handicrafts from middle east

spores and M/O ingested→ germinate → septicemia and possible death

Cutaneous Anthrax

pustules at site of infection may become systemic “black eschar”

Pulmonary anthrax

woolsorters disease is the most serious form of the diease

close to 100% mortality rate

inhalation of spores from contaminated sources causes the spores to move to the lungs organisms germinate and produce toxins and enzymes in the lungs

several exotoxins

destruction and necrosis of mediastinum, inflammation, and necrosis surrounding heart and lung tissues

Symptoms of Pulmonary Anthrax

fever, myalgia, chest tightness, cough, difficulty breathing, pneumonia, shock, and organ failure

Treatments of pulmonary anthrax

ciprofloxacin and doxycycline

Vaccines against pulmonary anthrax

humans can get 6 doses of a subunit vaccine made of the protective antigen of anthrax

Epulopiscium

giant prokaryote

in 1985 it was discovered in the gut of a surgonfish

large, 80um by 600 um

so large first thought it was protozoan

no nucleus also rRNA analysis confirms as a prokaryotes

Epulopiscium Fishelsoni

guest at the banquet of fish

Mycobacteria

gram positive acid fast rods

cell walls contain a layer of waxy lipids called mycolic acids

this allows them to resist acid alcohol decolorization but also gives increased resistance to desiccation and disinfection

slow growers

myco is fungus due to filamentous growth and many are found in soil

Pathogens of mycobacteria

Mycobacterium tuberculosis- tb

M. leprae- leprosy

Corynebacterium

gram positive rods, very pleomorphic often club shaped

corynebacterium diptheria is diptheria

Propionibacterium

propionibacterium acnes- associated with acne

Gardenerella

gram variable rod

garderella vaginalis- implicated in vaginitis

Lactobacillus

includes members of the genera lactobacilli streptococci

important gram positive bacilli for the milk and yogurt industries

in humans found in intestinal, oral, and vaginal cavities

ferment CHOs to lactic acid

aerotolerant anaerobes

no cytochromes no respiration

secrete acid and make pickles, sauerkraut, yogurt

Staphylococcus

gram positive cocci that grow in grape-like clusters

S. Aureus

most important human pathogen

grows as yellow golden colony on agar plates

can be found on the skin and in nasal passages

can grow under high salt concentrations

causes many skin infections and serious infections as well as nosocomial infections (most serious is MRSA)

food posioning, acne, release toxins like toxic shock syndrome

S. epidermidis

normal skin flora

associated with nosocomial infections

heart valve and hip replacement surgeries

streptococci

gram positive cocci typically grow in chains

characterized by their patterns of hemolysis of RBCs

Streptococci on blood agar plates

alpha- partial RBC hemolysis→ greenish color, usually normal flora

beta- complete RBA hemolysis→ clear area most important human pathogens

gamma- no RBC hemolysis, not pathogenic

Alpha hemolytic streptococci pathogens

usually non-pathogenic, normal flora of mouth and oropharynx

s. pneumoniae- diplococci is a human pathogen that causes pneumonia and meningitis

s. mutans- causes plaques and cavities