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respond to any agent, non-specific
respond to particular agents – antigens
(1) Physical barriers -skin, mucous membranes
(2) Chemical barriers -antimicrobial substances in body fluids - saliva, mucus, gastric juices.
(3) Cellular defenses -elements of the blood – differentiation resulting in red and white cells
(4) Inflammation- Reddening,swelling, temperature increase
(5) Fever-Elevation of body temperature
(6) Molecular defenses - such as interferon and complement
2. Transport digested fats to the cardiovascular system.
3. Serves as a conduit for manyof the specific and
nonspecific defense mechanisms against infections and diseases.
Around site: Reddening, swelling,temperature increase at sight of insult.
Bradykinin stimulates pain receptors and prostaglandins intensify the effect.Information of insult goes body-wide!
Persistentand caused by the continued presence of the insult.
Causesthe formation of tubercles
due to the accumulation of monocytes, lymphocytes and macrophages walling off necrotic tissue to form a granuloma.
Regulated by the hypothalamus
Exogenous pyrogens come from outside the body and stimulate a cytokine response that is an endogenous pyrogen - exacerbates the temperature increase due to inflammation.
Helps to protect the victim (patient?) by creating a hostile environment for the infecting agent or toxin.
Elevatedbody temperature kills invading agent and/or inactivates toxins
Erythrocytes –Red blood cells
Platelets –short lived fragments from megakaryocytes
Leukocytes – White blood cells: Innate and adaptive* immunity.
Complement is a group of proteins found inblood, which can be activated and produce a cascade of effects. ·
There are two pathways - classical, alternate
Activities of the complement system are rapidand nonspecific
in opsonization, infectious agents are coated with specific antibodies (opsonins) and C3b complement making the agents susceptibleto phagocytosis
In immune cytolysis, complementcauses formation of lesions in the plasma membranes of the infectious agent and causes lysis
are large molecules, generally proteins, although antigens may be carbohydrates, nucleic acids, etc. Immunogens are antigens that can stimulate an immune response and are immunogenic.
Why are biofilmsimportant?
· Arresting biofilm development
· Inducing biofilms to return to a planktonicstate
· Reduce the prevalence of persister cells
· Prevent biofilm formation
· 1st Disease Measles
· 2nd Disease Scarlet Fever
· 3rd Disease Rubella
· 4th Disease Not considered a rashanymore.
· 5th Disease erythrovirus (parvovirus)B19
· 6th Disease Roseola
1. Breach of intact skin
2. Skin manifestations of systemic infections
3. Toxin-mediated skin damage
What are the classifications of bacterial infections of the skin?
• Abscess formation: Boils and carbuncles
• Spreading infections: Impetigo and erysipelas
• Necrotizing infections: Fasciitis and gangrene.
· Easily transmitted and usually cause infection in older patients.
· Folliculitis and other skin lesions – inflammation of the hair follicle – pimple,sty, abscess, furuncle, boils and carbuncle
· Nasal carriers of virulent S. aureus may suffer from recurrent boils – 105 organisms required in the absence of a wound.
· Boil begins after 2-4 days of inoculation lost.
Scalded skin syndrome
caused by exfoliatin produced by S. aureus. Destruction of the intercellular connections and separation of the top layer of the epidermidis
· Large blisters with clear fluid form and eventually the overlaying of the skin is lost.
· Can occur in wounds, not just in the genitalia area. Involves multiple organ systems. < 200 cases/year but > 90% of adults carry antibodies to TSST1.Cause by S. aureus. Strains release toxin.
Streptococcal Infections (1)
· Scarlet fever (scarlatina) – S. pyogenes also known to cause strep throat.
· Bacteria is infected with a phage – produces a erythrogenic toxin.
· Erysipelas-known for > 2000 years – is caused by hemolytic steptococci. Used to occur often after wounds and surgery.Sin infections.
· Pyoderma and impetigo caused byStaphylococci, Streptococci alone or in combination –pus producing skininfection.
· Celulitis – S. pyogenes and S.aureus.
o Extends deeper than erysipelas.
o Pathogen is isolated in only 25-35% of cases.
o Observing symptoms,
o Remove aspirates from the advancing edge of the cellulitis
o Site of trauma
o Skin biopsies
Radical excision of all
· Chickenpox and Shingles
· Smallpox/cowpox and monkeypox
• Mildestof the rash causing viral diseases
• ssRNAtogavirus – its principal impact is on the fetus.
• Priorto the vaccine nearly everyone caught rubella 50% of cases in children and 90%cases in adults are not recognized.
• Diagnosisserologic, IgM and IgG antibody titration.
• Thereis no treatment, only prevention by a combined attenuated vaccine (MMR)
•Paramyxoviridae,Pleomorphic, 150 – 300 nm, Enveloped, two glycoprotein spikes (H and F)
• Only1 antigenic type of measles
• Nearlyall individuals become unwell and develop disease- Highly infectious-
•After infection – lifelong immunity
• Koplik’sspot: small, red papules with white central dot appear on the inside of thecheek for 1-2 days. They are diagnostic formeasles.
• Humanherpes virus type 6 (HHV-6)
• Enveloped,icosahedral nucleocapsid. ds – DNA
• Abrupthigh fever -3 to 5 days
• Dropin fever-rash begins and lasts for 2 days
• Immunityis permanent
• Nospecific treatment
• Noavailable vaccine
· highly contagious viral disease that killed upto half of those infected
· Pox: Latin word "spotted”
· Variola Virus
· Among the most common infections in clinicalpractice.
· Account for 8.3 million office visits and300,000 hospital stays in the USA / year.
· Women affected 40x to 50x more than men.
· Bacterial infections usually acquired by theascending route:
· urethra (Urethritis)---- bladder(cystitis)-----kidney (pyelonephritis) ----occasionally blood stream
· In men, prostatitis can also occur (mainly dueto E. coli
Treatment of UTIs
co-amoxiclav (beta-lactam and beta lactamase inhibitor),trimethoprim (antimetabolite and nucleic acid synthesis inhibitor),co-trimoxazole (trimethoprim and sulfamethoxazole)
Rapid onset of symptoms such as:
• Dysuria, urgency and frequency
• Cloudy urine due to pus cells (pyuria), bacteria(bacteriuria) and blood (hematuria)
• Increasing density and mobility of humans
• Difficulty in engineering changes in the humanbehavior
• Absence of vaccines for almost all STDs
-Spread of STDs is inextricably linked with sexual behavior
• Gram-negativecocobacillus present in the urogenital tract in 20% to 40% of women.
• AtpH 5-6 G. vaginalis interactswith anaerobic microorganisms – Bacteroids and Peptostreptococcus
• Dischargeis frothy and has a fishy smell.
• Menoccasionally get balantitis – infeciton of thepenis that corresponds tovaginits – lesions appear on the penis following sexual intercourse with awomen that has vaginitis.
• largeflagellate protozoa – 4 anterior flagella and undulating membrane.
• OptimumpH pH 5.5-6.0
• Female:intense itching, copious white discharge – consistency of raw egg white.
• firstdescribed by Albert Neisser – 1879
• Gram-negativediplococcus resembles a pair of coffee beans facing each other.
• -Secondmost commonly reported notifiable disease in the US
• -Humansare the only natural hosts.
• -Transmittedby carriers (for 5-15 yrs)
• -1000organisms are enough for infection.
• -95%males infected have pus dripping fromurethra within 14 days.
• -Sitesof infection:
· Men – urethra – anal canal - pharynx
· Female – cervix – urethra-anal canal- pharynx
• -Disseminatedinfections cause:
· -Bacteremia, fever, joint pain, endocarditis andsin lesions – pustular, hemorragic or necrotic.
Treatment of gonnohea
1st available were thesulfonamides
• Caused by Treponema pallidum –spirochete, highly motile, fastidious.
• Only identified in 1905; known by the name“great imitator”
• Currently less common than gonorrhea
• Transmitted by sexual means but also in otherbody fluids such as saliva.
• Not transmitted in food, water, air or arthropodvectors.
• Humans are the only reservoir.
Syphilis Diagnosis and treatment
DNA analysis of tissue; fluorescentantibody; treponemal immobilization tests.
Treatment –Penicilllin G.
No vaccine available
Recovery from syphilis does notconfer immunity
• Called soft Chancre to distinguish from thehard, painless chancre of syphilis.
• Caused by Haemophilus ducreyi – smallGram-negative rod arranged in strands.
• Identified by Augusto Ducrey – Italiandermatologist in skin lesions in 1889.
• Relatively rare in the USA, mainly immigrants.
• Worldwide incidence thought to be greater thansyphilis or gonorrhea.
• Chancresare extremely infective - soft, painful and bleed easily. Occur 3-5days afterexposure.
• Lesionsoccur in labia and clitoris of females and on the penis of males. Can alsooccur in tongue and lips.
• Medical personnel sometimes acquire lesions onthe hands merely from contact with chancres
Acquired through sexual intercoursein most cases.
Can survive for short periods oftime in moist areas
Genital herpes symptoms and treatment?
• Females– vesicles appear in the labia, vagina and cervix
• Males– tiny vesicles appear on the penis and foreskin
Treatment- Acyclovir, famciclovir and valacyclovir.
· >120 distinct types of HPV.
· All HPV infect skin or mucosal surfaces
· Different types are adapted to specific regionsof the body
·Incidence of HPV as increased significantly
· 80% of women infected by the age of 50.
· Current incidence rate 20% among women.
· Condylomas aka genital warts – appear on thepenis, vulva and perianal regions
HPV infections (2)
· Incubation period: 1-6 mon. Immune response- between 3-9 mon.
· HPV does not have a viremic stage
· Infection is transient in 90% of cases with a mean duration of 8 months.
· 13 strains cause 99% of all HPV cancers.
· Warts temporary increase in number and size during pregnancy but decrease after delivery.
· Infants can be infected during delivery.
How is Pharyngitis-Streptococcal Pharyngitis acquired?
What are the symptoms?
What is the diagnosis?
· inhalation of aerosoles
· Contaminated food, milk and water
• swellof lymph nodes and adenoids
• Tendertonsils with white lesions.
• +throat culture
• Enzymelabeled antibody screening test
What causes Laryngitis&Epiglottitis? What are the symptoms?
• Haemophilus influenzae
• Streptococcus pneumoniae
• swallowing very painful (drooling)
• Speech muffled
• Closing of the airway – inflammation
• Difficult breathing
• Can result in death
What causes Bronchitis?
What are the symptoms?
• ~15% of the population has chronic bronchitis.
• S.pneumoniae, Mycoplasma pneumoniae and several species of Haemophilus,Moraxella, Streptococcus and Staphylococcus
• Coughup sputum
• Coughlasts a long time.
• Respiratory membranes are damagedSevere shortness of breath
• Peaksin the Fall and Spring
• About200 ≠ viruses can cause colds
• Causedby Rhinovirus 30%-60% of the time – > 100 types of Rhinovirus
• Influenzavirus 5%-15%
• Parainfluenzavirus (peaks in late summer)
• Coronavirus(mid- December)
• Respiratorysyncytial virus
• Canalso be caused by bacteria – Chlamydophila pneumoniae
• Sore throat
• Nasal congestion
• Swelling of your sinuses
• Mood changes (in children)
• Several viruses
• 60-80% of infants have acute otitis media
• Toddlers have 1-3 episodes per year.
• Can lead to pneumonia
• Inflammation,irritation and infection
• Drainage from the ear
• Ear pain
• Hearing loss
• Itching of the ear
• Sometimes voice loss
• Tympanostomy tubes – little cylinders placed through the tympanic membrane
· whooping cough
• S.pneumoniae, S. aureus, K. pneumoniae, Mycoplasma pneumoniae,P. aeruginosa.
• Lobarpneumonia - S. pneumoniae 95% of cases
• Bronchialpneumonia – often appears as a secondary infections
-lacks the deposits characteristic of lobar pneumonia.
• Transmitted by respiratory droplets
• Mild respiratory symptoms
• Violent chills
• High fever (106oF) – 5-10 days.
• Chest pain
• Sputum containing blood, mucous and pus
Diagnosis- clinical observations, x-rays or sputum culture
•Immunity to the specific serotype of S. pneumoniae that caused the infection
• Vaccine for S. pneumoniae – contains 23 serotype antigens
• Re-vaccination every 10 years
• ~80% of unvaccinated population exposed contract the disease
• Tends to occur sporadic
• 50% of cases occur in the first year of life.
• Considered the least well controlled reportable bacterial vaccine-preventable disease in the US
• Bordetellapertussis – small, aerobic, encapsulated Gram-negative coccobacillus –isolated in 1906
• PCR, currently most effective method, is used to detect DNA sequences of Bordetellapertussis
• Culturing on charcoal-blood agar medium with penicillin
• Fluorescent-antibody stain also used to identify the organism
Treatment- Early treatment is essential
•If not given early, antibiotics will not alter the course of the illness or reduce the length of time the patient is contagious
•≥1month of age -azithromycin, clarithromycin and erythromycin <1month of age, azithromycin is preferred
Prevention- Pertussis whole cell vaccine - but was not completely safe. Acellularpertussis (aP) vaccine 5 doses of the vaccine
• Known to exist for at least 3000 yrs.
• Still a major problem today
• 1/3 of the worlds population has TB
• 3 million deaths/year. 10 million new cases/year
• 1882- Robert Koch identified M. tuberculosis
• Obligate aerobes.
• 12-18 hours generation time – visible colony in 8 weeks.
• Remain viable 6-8 months in dried sputum.
• Sensitive to direct sunlight
• Spreads through the air via droplets when a person with active TB:
• Coughs, Speaks, Laughs, Sneezes, Sings
• Fomites (contaminated surfaces, food, etc.) do NOT appear to facilitate spread
TB is NOT spread by:
• shaking someone’s hand
• sharing food or drink
• touching bed linens or toilet seats
• sharing toothbrushes
Symptoms of TB
• Perpetual cough
• Weight loss
• Night sweats
• Bloody sputum
• Sputumculture, genetic probes
• Skintesting – Mantoux tuberculin skin test- purified protein derivative (PPD) isinjected intracutaneously – examined 48-72 hrs later.
• Isoniazid and rifampin -1 year.
• Multidrug-Resistant TB (MDR TB) - resistant to at least two of the best anti-TB drugs,
• Extensively Drug-resistant TB (XDR TB) - rare type of MDR TB. XDR TB -resistant to isoniazid and rifampin, plus resistant to any fluoroquinolone and at least one of three injectable second-line drugs (i.e., amikacin, kanamycin, or capreomycin).
• Bacillus Calmetre-Guerin Vaccine aka BCG vaccine
• 412BC– Hippocrates described an influenza-like outbreak.
• The word comes from the Italian language meaning “influence” referring to theinitial belief that the illness was caused by astrology
• Swine flu aka spanish flu – 1918-1919 – 20-40 million people died
• 2009– 59 million cases in the US – 12000 deaths.
Symptoms of influenza
• Usually start suddenly 36-48 hrs after infection
• High fever, headache, muscle soreness, tiredness (can be extreme), cough, sore throat, runny/stuffy nose, body aches, diarrhea and vomiting (more common in children)
• Fever lasts about 3 days
• Accute phase over in about a week.
• Cans pread disease 1 day before symptoms appear and 5 days after
• Testscan only determine if you have the Flu within the first 2-3 days of illness.
• Virus cultured in embryonated chick eggs and call lines
• Amantadine(Symadine) – blocks influenza A virus replication
• Rimantadine(Flumadine) – more effective and less toxic – demonstrated to inactivate both Aand B viruses.
• Oseltamivir(tamiflu) – neuraminidase inhibitor
• Vaccine– killed virus vaccine
• Thevaccine developed with the 2009 virus has been shown to produce cross-reactingantibodies
-Small amount in blood, large amount in body secretions. It has 2 forms. Blood form,non-secretory.
Secretory form, found in secretions, has 2 monomer units, held together by a joining chain with an attached secretory component – protects from proteolytic enzymes
Main class of antibodies found in blood 20% of all plasma proteins, produced during a secondary response. Only one that can cross the placenta. Also found in milk and colostrum
IgD-Found mainly on the surface of B cells and is co-expressed with IgM. IgD also binds basophils and mast cells, activating them to produce antimicrobial factors to participate in respiratory immune defenses.
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