Term
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Definition
inhospitable to most microbes
dry
perspiration and sebum contains nutrients
salt inhibits microbes
lysozyme hydrolyzes peptidoglycan
fatty acids inhibit some pathogens
defensins are antimicrobial peptides |
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Term
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Definition
gram positive bacteria
Staphylococcus (Low GC)
Streptococcus(Low GC)
Diphtheroids (corneforms, eg Propionibacterium acnes) (high GC Gram+) anaerobic, inhabit hair follicles
can withstand drying, fatty acids, low pH, high salt
some yeasts |
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Term
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Definition
Gram+, low GC cocci in clusters
Coagulase (an enzyme clots fibrin in blood) +/-
majority of skin flora consists of coagulase- S. epidermis
all pathogenic S. aureus are Coagulase +
Pathogenic S. aureus also produce extracellular enzymes and toxins
cause: folliculitis, furuncles (boils), carbuncles
toxemias (occur when toxins enter bloodstream)
(scalded-skin syndrome, toxic shock syndrome) |
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Term
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Definition
occurs when toxins enter the blood stream
scalded skin syndrome
toxic shock syndrome |
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Term
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Definition
Gram + (low GC) cocci in chains
hemolysins (beta, alpha, and gamma hemolysis)
classified into groups-according to hemolytic enzymes and surface antigens. Group A is the most important, and there's also groups B, C and O.
Many virulence factors: M protein, extracellular enzymes, and toxins
M protein on surface: anti-complement, anti-phagocytosis
cause: impetigo (isolated pustules) and Erysipelas |
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Term
| Invasive Group A Streptococcal infections |
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Definition
Streptokinases
Hyaluronidase
exotoxin A, superantigen
cellulitis
necrotizing fasciitis "flesh eating" |
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Term
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Definition
aeruginosa, dermatitis and others
gram negative, aerobic rods
five groups
unusual metabolism (grow on traces of organic substance in soap, liner adhesive)
environmental (soils and water)
opportunists (medical devices, contact solutions)
cause:
dermatitis (self limiting, 2 weeks) swimming pools, sauna, hot tub
wound and skin infections
otitis externa (swimmer's ear)
burn patient infections |
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Term
| Viral infections of the skin |
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Definition
warts-papilloma virus
fever blisters-herpes simplex (herpes) -latency trigeminal ganglion and recurrent lesions
chickenpox-shingles-VZV (Herpes): latency-dorsal root gangloin and painful dermal infections (dermatomes)
smallpox-variola virus (Pox)
Paramyxovirus-rubeola (Measles) |
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Term
| herpes simplex Virus 1 (HSV-1) and HSV-2 |
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Definition
Human herpes virus 1 and HHV-2
Cold sores or fever blisters (vesicles on lips)
Herpes encephalitis (up to a 70% fatality rate)
HSV-1 can remain latent in trigeminal nerve ganglia.
HSV-2 can remain latent in sacral nerve ganglia.
Acyclovir may lessen symptoms. |
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Term
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Definition
Varicella-zoster virus (VZV).
Transmitted by the respiratory route.
Causes pus-filled vesicles.
Virus may remain latent in dorsal root ganglia. |
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Term
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Definition
Reactivation of latent VZV releases viruses that move along peripheral nerves to skin.
Postherpetic neuralgia
Prevention: Live attenuated vaccine
Acyclovir may lessen symptoms |
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Term
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Definition
Measles virus (Paramyxoviruses)
Transmitted by respiratory route.
Prevented by vaccination (MMR).
Macular rash and Koplik's spots
Cause immunodeficiency
Encephalitis in 1 in 1,000 cases.
Subacute sclerosing panencephalitis in 1 in 1,000,000 cases. |
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Term
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Definition
Rubella virus (Togavirus).
Macular rash and fever.
Congenital rubella syndrome causes severe fetal damage.
Prevented by vaccination (MMR). |
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Term
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Definition
Caused by human herpesvirus 6 (HHV-6) and 7 (HHV-7)
High fever and rash lasting for 1–2 days |
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Term
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Definition
An inflammation of the conjunctiva
Also called pinkeye or red eye
Commonly caused by Haemophilus influenzae
Various other microbes can also be the cause
Associated with unsanitary contact lenses |
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Term
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Definition
Gram - cocci)
Neonatal gonorrheal ophthalmia.
Transmitted to a newborn’s eyes during passage through the birth canal
Prevent by ophthalmic ointment (antibiotics) at birth. |
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Term
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Definition
1) Inclusion conjunctivitis
At birth.
Swimming-pool conjunctivitis.
Treated with antibiotics ointment.
2. Trachoma
Leading cause of blindness (worldwide).
millions have the infection.
severe conjunctivitis, nodules, scarring of the cornea.
scars abrade the cornea leading to blindness. |
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Term
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Definition
Herpes simplex-1
Adenovirus - shipyard eye |
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Term
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Definition
herpetic keratitis (HSV-1)
Infection of cornea
may cause blindness
trifluridine is effective |
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Term
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Definition
| inflammation of the meninges |
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Term
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Definition
| inflammation of the brain |
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Term
| Bacterial meningitis (septic meningitis) |
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Definition
Three common causes (all have capsules)
Hemophilus influenza - young children
Neisseria meningitis
Streptococcus pneumoniae
Vaccines – all are conjugated carbonhydrates
Many others including: Listeria, TB, Staph, Strep
High mortality
Fever, headache, and stiff neck
Followed by nausea and vomiting
May progress to convulsions and coma
Diagnosis by Gram stain or latex agglutination of CSF
Treated with cephalosporins (first choice) |
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Term
| Haemophilus influenzae Meningtis |
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Definition
Occurs mostly in children (6 months to 4 years).
Gram-negative aerobic bacteria, normal throat microbiota
Capsule antigen type B
Prevented by Hib vaccine |
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Term
Neisseria Meningitis
Meningococal Meningitis |
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Definition
Caused by N. meningitidis
Gram-negative aerobic cocci with a capsule
Some people are healthy nasopharyngeal carriers
Begins as throat infection, rash
Serotypes B, C, Y, W-135, differ in US, Europe, Asia, Africa.
In US, sporadic miningococcal outbreak among college students live in dorm.
Vaccination recommended for college students. |
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Term
Streptococcus pneumoniae Meningitis
Pneumococcal Meningitis |
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Definition
Gram-positive cocci
70% of people are healthy nasopharyngeal carriers
Most common in children (1 month to 4 years)
Mortality: 30% in children, 80% in elderly
Prevented by vaccination |
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Term
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Definition
Caused by Listeria monocytogenes
Gram-positive rod
Causes stillbirth and neurological disease in animals.
Usually foodborne; it can be transmitted to fetus
Reproduce in phagocytes
Phage treatment of ready-to-eat meat
2011 United States listeriosis outbreak (30 deaths and total 146 confirmed cases in 28 states. |
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Term
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Definition
Caused by Clostridium tetani
Gram-positive, endospore-forming, obligate anaerobe
Grows in deep wounds
Tetanospasmin released from dead cells blocks relaxation pathway in muscles
Prevention by vaccination with tetanus toxoid (DTP) and booster (dT) |
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Term
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Definition
Caused by Clostridium botulinum
Gram-positive, endospore-forming, obligate anaerobe
Intoxication comes from ingesting botulinal toxin
Botulinal toxin blocks release of neurotransmitter, causing flaccid paralysis
Prevention
Proper canning
Nitrites prevent endospore germination in sausages |
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Term
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Definition
Caused by Mycobacterium leprae
Acid-fast rod that grows best at 30°C but very slow.
Grows in peripheral nerves and skin cells
Transmission requires prolonged contact with an infected person |
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Term
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Definition
Poliovirus
Transmitted by ingestion, a stable virus - acid stable
Initial symptoms: Sore throat and nausea
Viremia may occur; if persistent, virus can enter the CNS
Destruction of motor cells and paralysis occurs in <1% of cases
An enterovirus -> viremia -> neurons-destruction of motor neuron
Three serotypes - vaccines to each
Salk vaccine (IPV,1954), Inactivated virus
Sabin vaccine (OPV,1963), Attenuated virus |
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Term
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Definition
Caused by the rabies virus, a rhabdovirus
Transmitted by animal bite
Furious rabies: Animals are restless then highly excitable
Paralytic rabies: Animals seem unaware of surroundings |
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Term
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Definition
Virus multiplies in skeletal muscles, then brain cells causing encephalitis.
Incubation period may be very long
A fatal encephalitis
Few human cases - many animal cases
Domestic animals: dogs, cats, cattle
Wild animals: raccoons, skunks, bats, foxes
Symptoms:
muscle spasms of the mouth and pharynx and hydrophobia
Treatment and prevention:
Preexposure prophylaxis: injection of vaccine
Postexposure treatment: vaccine plus rabies immune globulin (RIG) |
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Term
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Definition
Arboviruses are arthropod-borne viruses that belong to several families.
Prevention is by controlling mosquitoes.
Many viruses: EEE, WEE, SLE, CE, WNE
Equine encephalitises are more severe
Usually transmitted by
mosquito <=> birds
Horses and man are "dead-end hosts"
Seasonal - mosquito activity
Sentinel chickens used to detect |
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Term
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Definition
Herpes virus encephalitis
Post-measles encephalitis & SSPE (Subacute sclerosing panencephalitis) |
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Term
| Transmissible Spongiform Encephalopathies |
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Definition
Caused by prions
Typical diseases
Sheep scrapie
Creutzfeldt-Jakob disease
Kuru
Bovine spongiform encephalopathy
Chronic and fatal |
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Term
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Definition
Bacteria in the blood.
Sepsis
Toxic reaction to septicemia.
Usually Gram negative (LPS released upon cell lysis)
Endotoxic shock - Gram negatives
Toxic shock due to Gram positives (Toxic shock syndrome of S. aureus).
Due to rapid release of cytokines.
Disseminated intravascular coagulation.
Fever & chills, accelerated breathing, and heart rate, drop in blood pressure, organ failure. |
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