common And Notable Bacterial Infections Flashcards
Most bacterial infections are
Opurtunistic
Something like acne treatable with antibiotics
Staphylococcus aureus
Clusters (staph)
Gram positive spheres (cocci).
Aureus is Latin for golden
S AUreus produces a yellow pigment that protects bacterium from ultraviolet light
Chemically protects it feom neutrophils (innate immunity cells)
Yellow pigment called: staphyloxanthin
Where is S. Aureus common
Normal inhabitant or nose
Can Infect hair follicle
How to get rid of S Aurelius
Typically by drainage and anriobiotic therapy
Exotoxins as they relate to S aureus
Damage host tissue and waken host defenses
S aureus food poisoning
Linked to creamy salads poultry and meat
Transmission easy if hands are not washed
Leads to nausea vomiting stomach cramps dehydration
Dif between intoxication and infection
Ur getting sick by the toxic released by pathogen not pathogen itself
Why is Staph aureus so peristanr
Very sturdy for being non spore forming
Can withstand: High salt Extreme PH high temps Months of air drying Many disinfectants
How does S aureus get into skin
Starts on skin gains entry
Causes
Pimples, boils, abscesses, wound infections, scalded skin syndrome and more
Some skin infections can penetrate through soft tissues, muscle bones
If staph gains access to deeper tissue it can cause
Toxic shock syndome and endocarditis, sepsis, meningitis, pneumonia
Virulence factors of staphylococcus aureus
Skin penetrating enzymes
Staph transmission
Skin skin contact Touching contaminated surfaces Sharing personal items Crowded areas Poor hygiene INCREASED CONTACT WITH STAPH (hospitals) Food borne illnesses
Methicillin resistant staphyloccocus aureus
MRSA is a staph strain that has become orevelant in last decade
Concern because it’s resistant to methicillin which interferes with cell wall synthesis
MRSA isn’t very dif from regular staph except that it’s resistant to methicillin
Nosocomial infection
Strains common in hospitals and transmitted in hospitals
What does staphyloccocus aureus need to cause disease
Access
What can be done against MRSA
New drugs like vancomycin, rifampin, tetracyclines
Resistance emerging though
Old drugs that are not commonly prescribed and therefore not a lot of resistance
Can do nothing to see if immune system can fight it
How big is MRSA problem
Annual cases 80,000
Animal deaths: 11,000
Streptococcus pyogenes
Normal part of micro biome
Can get into the skin from very small cuts
Express an acid fhat digests away skin cell layers
Streptococcus pyogenes necrotizing fasciitis
Can cause flesh eating and penetrating infections
Impetigo
Infections on the surface
Soar throat (pharyngitis)
Usually caused by a virus by irritations (such as mucus)
Causes “strep throat”
Can lead to possibly fatal complications including scarfler fever, meningitis, kidney disease and necrotizing fasciitis
Detection of pharyngitis is possible visually
Detection of a pyogenes is done with
A throat swab, perhaps supported by a throat culture
Strep throat virulence
Surface antigens that mimic host antigens (doesn’t seem foreign)
Specialized polysaccharides that prevent digestion by lysozime
Secretion of several toxins that have toxic effects on cells
Clostridium perfringens
An anaerobic spore forming bacteria commonly found in soil
Commonly found in animal intestines and raw meat
Can cause food poising
Causes diarrhea and stomach cramps
Clostridium perfringens can lead to what
Can also cause more serious diseases if ir is introduced to wounds
Needs to find access to deeper tissue before causing these
Gas gangreneis: bacterial infection that produces gas in gangrenous tissues
What is Gas gangrenes
These microorganisms are opportunistic and enter body through significant breakage
Bacteria causes myonecrosis: a condition of necrotic damage, specific to muscle tiesue
Gangrenous infection was most common…
In combat injuries (non sterile surgeries)
Diagnosed by large blackened sores that form as well as by cracklings noise (crepitus) caused by gas escaping tissue
Plague
Caused by bacterium called yerisinia pestis
Infects animal hosts most commonly the prairie dog
1000-2000 cases worldwide annually
How is plague treatable
Antibiotics if caught early
Y. Pestis is phagocytosed by…
Macrophages then evades the lysosome and replicated within the macrophage
So it actually likes macrophages
How does the plague spread
Different forms, bubonic and septicemic are most common (bites)
Bubos
Swollen lymph nodes in body
Pneumonic plague
Spread from person to person
Lyme disease
Bacterial disease carried by ticks
Infection mostly concentrated in the northeastern US but some cases throughout country
Early symptoms of Lyme
Bulls-eye rash around bite, fever, dizziness, muscles and head aches
Late symptoms of Lyme disease
Neurological limpness and local paralysis and cardiac
Some patients have continuing symptoms including aches and fatigue rhat are not fully understood
Borrelia burgdorferi
An expert immune evader
Complement system antagonism
Anti inflammatory cytokines production (counteracts cytokines)
Releases soluble antigens like aircraft chaff to distract antibodies
Antigenic variation
THIS ISVWHAF LEADS TO THE BULLSEYE WITH LYME DISEASE
How or why does borrelia burgderfori causes the bullseye rash
Antigenic variation
As the pathogen migrates feom center is switches antigen
The immune system has to constantly relearn how to fight disease
Result of this is the bacterium getting into bloodstream leading to desiminated disease
Borrelia Mayonii
Another pathogen that can transmit Lyme disease
Prevention of Lyme disease
Prevent tick bites
Check from ticks attached to skin upon returning from outdoes
Treatment for Lyme disease
2-4 weeks with antibiotics (doxycikin, amoxicillin) more successful if taken as early as possible
Tuberculosis
Ancient disease caused by mummies caused by mycobacterium teburculusis
Gets its name from teburcles it causes walled off structure of localized infection
85% of TB is limited to
Lungs, however the bacterium can infect many tissues including brain, meninges, kidneys, bones, etc
Nicknames of TB
Consumption, white plague
TB and immune response
Infects macrophages themselves
Macrophages engulf TB to destroy them
TB prevents fusion of the phagosome to he lysosome
Replicate within phagosome
Can then escape from the phagosome
Many microphones in one place, TB triggers calcification around them, builds a walled off area within the lung
Intitial infection stages of TB
- Inhaled M. TB bacteria encounter macrophages in the lungs
- Some of the phagocytized bacteria thrive inside the macrophages
Latent Tb Stage
The immune system detects that certain macrophages are infected and walls them off in fibrous granulomqs to limit spread
Active TB stage
- Occasionally the center of the granuloma liquefies and the walls break down, leading to an active infection that can transmit the bacterium to others
Where can M. TB live
Moist surfaces up to 6 months
Small closed rooms, intimate or crowded living conditions, lack of fresh air
Vitamin S is important for immune response for
TB
Treatment of TB
6-9 months of continuous antibiotic use
Some strains of multi drug resistant TB are emerging
2 approaches to preventing TB resistance
- Incarceration of individuals who do not follow drug regimen
- Directly observed therapy (DOT) public health worker visits patient at every dose and observes drug taking
Tetanus
Caused by clostridium tetani
Spores are often found in soil
Releases a toxin that interferes with the neurotransmitters that inhibit muscle contraction
Tetanus causes what
Spastic paralysis called “lockjaw”
Tdap vaccine
Tetanus, diphtheria and pertussis
Risk factors of tetanus
Puncture wounds, cultural practices of allying mud to wounds, IV drug users
The tetanus interferes with the action of what
GABA: a protein that would usually stop this process resultin in spastic paralysis
Clostridium botulism
Etiological agent
Spore forming
Can be found in improperly made sausages
Sores can be found in honey prefers anaerobic conditions
Used to treat migraines and muscle spasm
Beauty/recreational use for wrinkles and sweating
Mechanism of bostulism disease
Exotoxins enters blood and targets nerves
Botox blocks the synaptic cleft
Flaccid paralysis results (muscles don’t ever contact)
Infant botulism
Can happen if the spores of the bacteria get into an infants intestines (honey)
Wound botulism
Can happen if the spores of the bacteria get into a wound and make a toxin especially from dirty needles
Food borne botulism
Can happen by eating foods that have been contamination with botulinum toxin (improperly made or canned preserved foods)
Iatrogenic botulism
Can happen if too much Botox is injected for cosmetic or medical reasons
Adult intestinal toxemia
Very rare kind of botulism that can happen if the spores of the bacteria get into an adults intestines, grow and produce the toxin
Campylobacter jejuni
Most common food borne illness #1 cahsarive agent of GI illness
Member of the poultry micro biome (undercooked chicken)
Mechanism of campylobacter jejuni
Bacteria burrow through the mucosal layer of the intestine
Migrate through intestinal epithelial cells
Multiply beneath epithelial layer
Inflammatory response 2-5 days
Salmonella enteric a
Found in micro biome of birds, some mammals, and reptiles
Food and water can also be contaminated with the feces of infected people or animals
Some strains cause GI illness, others typhoid fever
Secretes a toxin that affects water transport in small and large intestines
Signs and symptoms of salmonella
Infection not toxin
Appear within 1/2 danys after consuming contaminated food and water
Fever abdominal cramps 4:7 days
Salmonella serovar typhi
Toxin!
Typhoid fever from typhoid toxin production (plasmid borne virulence factor)
Symptoms are sismilae but include a rose cooored spotted rash
Infectious dose for S. Enterica
Very high (1 million cells does not produce disease in healthy persons)
Escherichia coli
Lots of dif types
Harmful strains (food poisoning! Are usually from undercooked beef or bad veggies
Fecal transmission- oral transmission also possible
Shigella toxin
When E. coli is most dangerous
It colonized the large intestine causing cells to rupture leading to dysentery (blood in diarrhea)
Can be fatal due to blood loss and dehydration
Treatment generally limited to rehydration
Uropathogenuc E. coli
Uropathogenuc E. coli from the gut is the cause of 80% of community acquired urinary tract infections
Most important virulence factor of establishing bladder infection is likely the type 1, mannose sensitive, fimbria, which attaches to receptors on uroepethial cells
Feces or fecal particles get transported to the urethra due to
Anal sex
Improper hygiene
King car or plane rides
Diabetes
Cholera
Caused by vibrio cholerae
Releases cholera toxin
Triggers intestinal epithelial cells to release elecrolytes and water into the intestines
Generates water starchy colored diarrhea or rice water
Patients lose a ton of water, 50% or more of body weight
Death or recovery occurs within 48 hours
55% fatality
Vibrio cholarae
Bacteria cause no direct damage
Secreted toxins interfere with the ability of the intestines to reabsorb fluid
Can live in water and body fluids for long period of time especially warm weather
Cholera transmission
Consuming raw shellfish
Endemic in areas with water sanitation
Large infectious dose required
Cholera treatment
Oral rehydration
Antibiotics
Chlamydia
Caused by chlamydia trachomatis
Gram negative
75% of infected women have no symptoms
Most major cause of nongonococcal urethritis
STI’s lead often to
Pelvic inflammatory disease
Chlamydia in neonates
50% vertical transmission
Eye infections
Pneumonia
Gonorrhea
Nesseria gonorrheae
Gram negative bacterium
Antigenic variation means it can evade the immune system
In males, gonorrhea is
10-15% are asymptomatic
Usually exhibit symptoms such as painful ruination, yellowish white discharge from the penis
Untreated cases may cause inflammation in vas deference or glands can lead to infertility
In females gonorrhea
50-80% are asymptomatic
When symptoms are present they are usually mild such as painful burning sensation and discharge
Causes pelvic inflammatory disease
Can cross into bloodstream and affect skin heart and meninges
Gonorrhea in neonates
Can cause blindness
Screening of pregnant women JS routine, as is application of antibiotic eye drops
Respiratory system can be infected as well
Syphylis
Caused by treponema pallidum
Gram negative spirochete
Primary syphilus
Skin lesions called chancre (usually painless) filled spirochete
Latency leads to secondary syphylis
Secondary syphilis
At least weeks but sometimes years after exposure
Rash tons of other rarer symptoms
Tertiary syphilis
Leads to gummatous syphilis, neurosyphikis, cardiovascular syphilis
Usually not contagious
Results from latent syphilis
Latent syphilis
Proof of infection without symptoms
Last for many years
15-40% of people develop tertiary syphilis
Congenital syphilis
Organism crosses placenta
Infected newborns have
Notched teeth
Perforated palates
To get syphilis
Patient comes into contact with a sore
Prevention for syphilis
Barrier methods of contraception help but syphilis sores are not always limited to genitals
Treatment for syphilis
High dose penicillin tetracycline or doxycycline
Partner must also be treated otherwise ineffective
Treatment will kill the syphylis bacterium and prevent further damage but it will not repair damage already done
