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79 Cards in this Set
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- Back
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Fungi
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- Eukaryotes, spores used for reproduction
- Divided into yeasts and molds - Yeasts are round or oval and reproduce by budding - Molds are tubular structures called hyphae that grow by branching - Some are dimorphic and can be seen in yeast or mold form. |
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Protozoan Disease
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- unicellular
- classified by mode of motion - parasitic - eukaryotic - exists in 2 forms: -- trophozoite: infectious part grows in host -- cyst: transmission form |
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Infectious diseases caused by Bacteria
*-*- Important virulence factors for Pathogenicity -*-* |
- Cell Wall: peptidoglycan - osmotic pressure
- capsule/attachment devices - pili, fimbrae, adhesions, pili biofilm, resist phagocytosis - spores: endospores - survive harsh environment - toxins: -- exotoxin = proteins -- endotoxin = LPS - enzymes: breaks down barriers & allows to spread |
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Structure of the Skin
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Functions of the Skin
- important to temperature regulation - barrier against microbial invaders - presence of normal flora Composed of two layers - dermis - epidermis -- covered with salt and an oily lipid called sebum -- prevent the growth of many microorganisms -- replacement of the outer layers of the epidermis helps remove microbes attached to the skin surface |
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FOLLICULITIS (pimple)
[bacterial] |
- infection of a hair follicle
-- sty: occurs on eyelid base -- furnucles: spreads infection -- carbuncles: multiple furnucles grow together - Mostly caused by Staphylococcus - [Treatment: methicillin] [Virulence factors: enzymes, structures to evade phagocytosis, toxins] (MRSA) |
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STAPHYLOCOCCAL SCALDED SKIN SYNDROME (SSSS)
[bacterial] |
- Results in separation of cells of the outer epidemis from one another
-- Outer skin layer peels off in sheets - Staphylococcus aureus strains -- exfoliative enzymes toxins cause SSSS pathogenesis -- no scarring since dermis is unaffected -- disease occurs primarily in INFANTS -- transmitted person-to-person -- treated by administration of antimicrobial drugs |
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Impetigo and Erysipelas
[BACTERIAL] |
- only caused by strep -
- Characterized by small patches on the face and limbs, mostly in children -- Develop into pus-filled vesicles that can itch intensely -- Erysipelas develops as large patches when the infection spreads to the surrounding lymph nodes-mostly in elderly -- Both transmitted by person-to-person contact + The bacteria invade where skin is compromised + Caused by S. aureus or Strep. pyogenes [Virulence factors] - M protein interferes with phagocytosis (similar to capsule) - hyaluronic acid acts to camouflage the bacteria - pyrogenic toxins stimulate fever, rash, and shock ** If Impetigo spreads --> Erysipelas ** |
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Necrotizing Fasciitis
[BACTERIAL] [Flesh Eating Bacteria] |
- Caused by S. pyogenes
[Virulence Factors] - Various ensymes facilitate invasion of tissues: Streptokinase - Hyaluronidase - Exotoxin A - Streptolysin S (Streptolysin causes tissue death) - Pathogenesis and Epidemiology + enters through breaks in skin + spread by direct contact form person-to-pertson + treated by antibiotics: clindamycin & penicillin **Can be systemic** + Difficult to diagnose in early stages because symptoms are nonspecific & flu-like |
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ACNE
[BACTERIAL] |
- Pathogen and Virulence Factors
-- Commonly caused by PROPIONIBACTERIUM acnes -- Gram (+), rod-shaped diphteroids -- Commonly found on the skin + Bacterium is part of normal flora [Diagnosis, Treatment, & Prevention] -- Diagnosed by visual detection of the skin -- Treatment is typically with antimicrobial drugs and drugs that cause exfoliation of dead skin cells -- Accutane is used to treat severe acne -- A new treatment uses a blue light wavelength to destroy P. acnes ** Lives deep under skin; can be anaerobic which leads to most problems** |
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Pseudomonas Infection
[BACTERIA] |
**Most common -- Opportunistic**
- Pathogenesis: -- Infection can occur in burn vitcims; grows under skin -- The bacteria kills cells, destroys tissue, and triggers shock -- P. aeruginosa is rarely part of the microbiota; can cause infections throughout the body -- Treatment difficult due to the resistance to multiple drugs and disinfectants -- is widespread and thus infections are not easily prevented [Signs & Symptoms] - Fever, chills, and shock and sometimes a green color due to the pigment, pyocani - found in the soil, decaying matter, moist environments [Virulence Factors] - Various adhesions - toxins - a polysacchride capsule |
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Cutaneous Anthrax
[BACTERIA] |
+ Cause: Bacillus Anthrax (Gram +)
+ Forms endospores, always present in soil + Portal of Entry: direct skin contact + Signs/symptoms: black skin lesion that forms an eschar -- not fatal + Incubation period: immediate response + Susceptibiliy: animal handlers (livestock) + Treatment: Ciprofloxacin +Prevention: Vaccinate livestock |
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Poxviruses
[Viral diseases of the Skin] |
+ Human Pox pathogens: smallpox, orf, cowpox, and monkeypox
+Smallpox first human virus that was eradicated (early 70's) + Disease due to the poxviruses progress through stages +Enters via inhalation + Rash --> papules --> vesicles --> pustules +No treatment, only vaccination |
+ papules: red rash
+ papules: red rash + postules: pus filled, deep infection |
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Herpes Infection
[VIRAL] |
+ 80% of population has HSV1
[Signs & Symptoms] -Latent- +Characteristic slowly spreading skin lesions + infections also occur at various other body sites + Recurrence of lesions due to activation of latent virus [Diagnosis, Treatment & Prevention] + Diagnosis made by presence of characteristic lesions + Immunoassay reveals presence of viral antigens + Chemotherapeutic drugs help control the disease but not cure it + Transforming infection --> changes DNA causes cancer + persistant = doesn't kill host +DRUG of choice: Acyclovir |
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Chicken Pox and Shingles
[VIRAL] |
+ Cause: Varicellovirus (varicella-zoster virus)
+ Portal of Entry: Respiratory tract (inhale virus, shows up as rash) + Signs/Symptoms: characteristic rash + Incubation period: two to three weeks + Susceptibility: Unvaccinated individuals or those who have not had it + Treatment: supportive therapy + Prevention: attenuated vaccine |
*Attenuated: weakened live virus; may not produce lifetime immunity
* worse as adults (immunopathology) |
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Rubella
[VIRAL] |
+ Cause: Rubella virus
+ Portal of Entry: respiratory tract + Signs/symptoms: rash, swollen lymph nodes + Incubation Period: 7-14 days + Susceptibility: Unvaccinated individuals, fetus + Treatment: Supportive therapy + Prevention: Vaccination with MMR vaccine |
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Measles
[VIRAL] |
+ Cause: Morbillivirus (rubeola virus) (childhood)
+ Portal of Entry: Respiratory tract + Signs/symptoms: Koplik's shots diagnostic + Incubation period: 8-12 days + Susceptibility: Unvaccinated individuals + Treatment: Supportive therapy + Prevention: Vaccination with MMR vaccine + no cure |
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Mycoses of the Hair, Nails, and Skin
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+ Mycoses are diseases caused by fungi
+ Mainly opportunistic pathogens + Mycoses are classified by infection locations --Superficial on the surface -- Subcutaneous: in the hypodermas and muscles -- Systemic: affects numerous systems (capable of spreading through cardiovascular system) |
CUTANEOUS & SUBCUTANEOUS MYCOSES
+ fungi that grow in tissues can produce skin lesions + include various fungal infections -- Dermatophytoses -- Chromoblastomycoses -- Phaeohyphomycoses -- Mycetomas |
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Dermatophytosis
[FUNGAL] |
+ Grow on skin, nails, and hair
+ Differ from superficial fungal infections due to the underlying tissue damage +Classified by natural habitat -- Anthropophili: associated with humans only -- Zoophilic: associated with animals -- Geophilic: soil fungi |
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Parasitic Infestation of the Skin
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+ Parasitic protozoa and arthropods can infect skin and cause disease
+ Leishmaniasis -- Skin & Systemic infection -- Spread by sand-fly -- Cause of most Gulf syndrome -- Affects most AIDs patients (malaria & tuberculosis) + Scabies -- Intense itching and localized rash at infection site -- The mite Sarcoptes scabiei is the causative agent (parasite) -- Transmitted via prolonged body contact such as sexual activity -- Treated with miticide lotions and cleaning contaminated clothes and towels |
◌ Leishmaniasis: Anthropod-borne: carried by protozoa vecto
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Trachoma
[Bacteria] |
*Leading cause of non-traumatic blindness*
◌ Cause: Chlamydia trachomatis ◌ Portal of entry: inoculated into babies eyes during birth ◌ Signs/Symptoms: Discharge and deformed eyelids due to infection results in scarring of the conjunctiva and the cornea and can lead to blindness ◌Susceptibility: Typically a disease of children but adults can also be affected ◌Treatment: antimicrobials to eliminate bacteria and surgical correction to damaged eyelids can help prevent scarring |
◌ Antibiotic can easily treat
◌ Irreversible damage |
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Other Microbial Diseases of the Eyes
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◌ Bacterial infections of the skin and reproductive tract can affect the eyes
◌ Sites - infections of the sebaceous glands near the eye - Causative agent: S. aureus ◌ Opthalmic neonatorum: inflammation of the conjunctiva and cornea of a newborn - Causative agent: N. gonorrhoeae ◌ Conjunctivitis - inflammation of the conjunctiva - H. influenzae most common bacterial cause ◌ Keratitis - inflammation of the cornea (could lead to blindness) |
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Portals of Infection of the CNS
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◌ CNS is anexic environment
- It has no normal flora ◌ Pathogens may access the CNS in several ways - Breaks in the bones and meninges - Medical procedures - Traveling in peripheral neurons to the CNS - infecting and killing cells of the meninges resulting in meningitis ◌ ****Bacterial infections are more serious than Viral infections**** |
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Bacterial Meningitis
[SWITCH WITH OTHER CARD!] |
◌ S. pneumoniae
- Leading cause of meningitis in adults - VF: capsules - Only encapsulated strains are virulent ◌ N. meningitidis (meningicoccal) - VF: fimbria, capsule, and LOS required for virulence (pili) - can become epidemic ◌ H. influenzae - Leading cause of bacterial meningitis PRIOR to development of vaccine ◌ L. monocyotgenes - Causes disease in fetus, immunocompromised individuals - Production of listeriolysin O aids in intracellular living - Listeria transmitted by contaminated food |
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Bacterial Meningitis
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◌ Inflammatory bacterial infection of the meninges
◌ Signs/symptoms (develops rapidly) - Sudden high fever and severe meningeal inflammation - Inflamed cranial meninges: severe headache, vomiting, pain (strictly brain) - Inflamed spinal meninges: stiff neck, altered muscle control (strictly SC) - Brain infection, encephalitis: Result in behavioral changes, coma, death [Diagnosis, Treatment, & Prevention] ◌ Diagnosed with culturing of bacteria from CSF from spinal tap ◌ Treat with various antimicrobial drugs ◌ Vaccine: H. influenzae, pneuomococci, meningococcal strains ◌ Foods such as milk, cheese, and undercooked meats can be contaminated |
If bacterial can be treated with antibiotic
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Leprosy
[Hansen's Disease] [BACTERIAL] |
◌ Cause: mycobacterium leprae
- Gram (+) bacillus with mycolic acid in cell wall [acid-fast - thick waxy coat] ◌ Disease manifesets in two forms: 1. Tuberculoid leprosy - nonprogressive 2. Lepromatous leprosy - progressive tissue damage ◌ Transmitted via contact ◌ M. leprae grows best in cooler regions of the body ◌ Diagnosed based on the sign and symptoms and confirmed by presence of acid - fast rods in samples |
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Botulism
[BACTERIAL] |
▢ Cause: Clostridum botulinum
- Different strains produce one of seven neurotoxins - Illness is caused by INGESTION OF TOXIN ▢ Three forms: (endospores) 1. food-borne: progressive paralysis of all voluntary muscles 2. infant- bacteria grow in the intestine producing non-specific symptoms (ingestion of endospores) 3. Wound botulism: symptoms like those of food-borne ▢ three approaches to treatment: 1. washing of intestinal tract to remove Clostridium 2. Administration of botulism immune globulin (antibotox antibody) 3. Treatment with antimicrbial drugs ▢Prevention involves destroying endospores through proper canning techniques |
▢ Gram (+) bacteria
▢ Exotoxin - neurotoxin ▢ obligate anaerobe ▢ Characteristics - diarrheal diseases, deep wound infections, nervous system infections ▢Anti-serum: contains antibodies of specific infection |
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Viral Diseases of the Nervous System
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▢ Viruses more readily cross the blood-brain barrier
▢ Viral infections are more frequent in the Nervous System ▢ Viral diseases include: - meningitis - polio - rabies - encephalitis |
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Viral Meningitis
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▢ Most common form of meningitis
▢Typically a milder disease than bacterial or fungal meningitis ▢ 90% of causes caused by viruses in the genus ENTEROVIRUS - Attack cells in the intestinal tract but don't cause gastrointestinal illness ▢ Spread in respiratory droplets and feces ▢ Characteristics signs and symptoms that occur in the absence of bacteria in the CSF ▢ NO specific treatment exists |
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Polio (Poliomyelitis)
[VIRAL] |
▢ Cause: Poliovirus
▢ four conditions can occur: 1. Asymptomatic infections (most) 2. Minor polio-nonspecific symptoms 3. Nonparalytic polio - muscle spasms and back pain 4. Paralytic polio - produces paralysis (only small fraction) ▢ Water-borne ▢ Today polio exists ONLY in Africa & Asia ▢ TWO vaccines exist |
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Rabies
[VIRAL] |
▢ Cause: Rabies virus
▢ Zoonotic disease ▢ Portal of entry: bite or scratch from an infected animal ▢ Signs/symptoms: Pain or itching at infection site, exhibits hydrophobia - Neurological manifestations --> will die ▢ Incubation period: generally one to two months ▢ Susceptibility: wild animals, animal handlers ▢Treatment 1. inject antibodies 2. postexposure prophylaxis 3. rabies vaccine |
▢ Three stages:
1. prodromal 2. excitative 3. paralytic ▢Lymphotrophy: spread thru lymph system |
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Arbovirus Encephalitis
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▢ Arboviruses are arthro-borne viruses
- Viruses are transmitted by hosts by blood-sucking arthropods (mosquitoes) ▢ Mosquito-borne arboviruses cause various types of arboviral encephalitis ▢ Zoonotic disease so they rarely affect humans ▢: Signs/Symptoms: mild, cold-like symptoms; virus that cross blood-brain barrier can cause encephalitis with symptoms similar to meningitis ▢ Treatment: vaccine for humans, unsure for humans |
▢ Diagnosis made based on signs and symptoms and positive test for antibodies against specific arboviruses in the CSF
▢ Treatment is supportive ▢ Prevention involves limiting contact with mosquitoes - use netting and insect repellent - reduce mosquito population by getting rid of stagnant water ▢ birds, horses, small rodents can also be carriers |
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Crytococcal Meningitis
[FUNGAL] |
▢ Cause: Crytococcus neoformans
▢ Portal of entry: inhalation of spores or dried yeast cells (respiratory tract) ▢ Signs/symptoms: prolonged cough and similar bacterial meningitis symptoms ▢ Incubation: unknown but likely 2-9 months ▢ Susceptibility: immunocompromised persons, those exposed to bird droppings [Opportunistic] ▢ Treatment: Amphotericin B and 5-fluorocytosine ▢ Prevention: difficult due to prevalance of fungus |
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Prion Disease
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▢ Infectious disease causing proteins
▢ Abnormally folded prion proteins can act to cause normally proteins to adopt the abnormal conformation ▢ Unclear why the initial prion misfolds ▢ Disease may be triggered by transplants, contaminated surgical instruments and injection of growth hormones from infected pituitary glands |
▢ Examples:
- Scrapie: Kuru --> sheep disease - CJD: human - mad cow disease - BSE: mad cow disease |
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Microbial Diseases of the Cardiovascular System:
SYSTEMIC INFECTIONS |
▢ Systemic: felt throughout body
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Septicimia and Toxemia
[BACTERIAL] |
▢ OPPORTUNISTIC or NOSOCOMIAL
▢ Septicemia: presence of microbes in the blood ▢ Toxcemia: release of bacterial toxins into the blood stream ▢ Gram (-) is more common than gram (+) ▢Signs/symptoms: FEVER, chills, nausea, vomitting, malaise - Septic shock can develop rapidly; very ~Low BP~ due to dialation of the blood vessels ▢ May result in release of: - Exotoxins: released from living microorganisms - Endotoxins: released from G(-) bacteria |
▢Gram (-) septicemia more dangerous than gram (+)
- Leading cause of death in nursing homes ▢ Virulence Factors: - Presence of capsules - LPS or endotoxin produced G(-) bacteria - capacity to capture iron needed for bacterial growth |
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Endocarditis
[BACTERIAL] |
▢ Cause: Viridian streptococci causes almost half of the cases
- Streptococci most infectious to humans ▢ Portal of Entry: inoculation of bacteria into the blood via open wounds ▢ signs/symptoms: fever, fatigue, malaise, tachycardia ▢ Incubation period: weeks to months ▢ Susceptibility: immunocompromised people or prolonged invasive medical procedures ▢ Treatment: intravenous antibiotic therapy ▢ Prevention: high risk patients can be given prophylactic antibiotics when needed |
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Gas gangrene
[BACTERIAL] |
▢ Cause: Clostridium species
▢ Portal of entry: Via traumatic event, puncture wounds ▢ Signs/symptoms: pain and swelling at injury site, fever, foul-smelling drainage ▢ Cuts the OXYGEN to tissue ▢ Susceptibility: Presence of deep, lacerating wounds ▢ Treatment: surgical removal of dead tissue and antibiotic treatment ▢ Prevention: properly cleanse wounds |
▢ obligate anaerobe
▢ endspores ▢ rod-shaped ▢ gram (+) ▢ schemia: causes necroticism therefore surgery |
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Plague: a Zoonotic Disease
[BACTERIA] |
▢ Caused by Yersiria pestis
▢Two forms: - Bubonic Plague: enlarged, inflamed lymph nodes called buboes - Pneumonic plague: when the bacterium spread to the lungs ▢ Carried by rodents in SW US (in NV&CA) ▢Virulence Factors: Adhesins, capsules, and resists phagocitic killing ▢ Spreads freely; anthropod disease |
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Lyme Disease: a Zoonotic Disease
[BACTERIA] |
▢ A tick-borne disease caused by Borrelia burgdorferi
▢ Three phases: form a red rash (resembles a bulls eye) to neurological symptoms to severe arthritis ▢ Two events contributed to increase in Lyme Disease 1. Human populations moving to woodland areas 2. Protection of the deer population ▢ Treatment:early phases - antimicrobial drugs; later phases are hard to treat since symptoms are often caused by immune system ▢Prevention: use repellants w/ DEET and protective clothing |
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VIRAL Cardiovascular and Systemic Diseases
▢ Systemic virus |
▢ Cause: Epstein-Barr virus
- Severe sore throat and fever followed by enlarged lymph nodes ▢ Diagnosis: made based on the presence of large, lobed B lymphocytes and neutropenia ▢ A latent infection worse for immunocompromized individuals - Transmission: saliva and virus infects B lymphocytes - No treatment, resolved by itself - Many are infected and hard to control - Can become anemic due to infection |
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Malaria:
a systemic infection caused by Protozoa |
▢ Caused: Plasmodium species
▢ Spread by Mosquito - Endemic in over 100 countries though not in the US ▢ Life cycle occurs in three main stages 1. mosquito 2. body --> liver cells 3. RBC - Partly goes through red blood cells ▢ It takes 48-72 hours for infection to cycle through body --> chills fever |
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Toxoplasmosis
[Protozoa, Parasitic] |
▢Cause: Toxoplasma gondii
▢ Signs and Symptoms: Majority of cases have no symptoms - Symptoms in those with poor immunity - Include fever, malaise and inflammation of the liver, lungs, and heart ▢ ***Symptoms in a fetus***: stillbirth, fetus, mental retardation ▢ Cats are definitive host |
▢ Infections usually arise from consuming undercooked meat containing parasite
▢ Transmission across placenta can also occur ▢ Diagnosis: by detecting organisms in tissues ▢ Treatment: usually unnecessary except in AIDS patients and newborns |
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Streptococcal Respiratory Diseases
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▢ Cause: Group A streptococci (S. pyrogenes) (very infectious)
- Commonly called strep throat ▢ Virulence factors: M proteins (act like capsule), hyaluronic acid, capsule, streptokinases, C5a peptidase, pyrogenic toxins streptlysins, hemolysin (destroys RBC) ▢ Portal of Entry: inhaling droplets ▢ Signs/Symptoms: Sore throat, difficulty swallowing; may progress to scarlet or rheumatic fever ▢ Susceptibility: Children typically ▢ Treatment: Penicillin is the standard treatment ▢ Prevention: Infectious individuals are infectious for two days after treatment and should stay at home |
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Diphtheria
[Bacteria] (part of normal flora) |
▢ Cause: Cornybacterium diphtheriae
▢ Virulence factors: Diphtheria toxin prevents polypeptide synthesis and causes cell death ▢ Portal of entry: Person-to-Person via respiratory droplets or skin contact ▢ Signs/symptoms: sore throat, oozing fluid that hardens into a pseudomembrane that can obstruct airways ▢ Susceptibility: Immunocompromised or nonimmune individuals develop symptomatic infections ▢ Treatment: Administration of antitoxin and antibiotic ▢ Prevention: Immunization - DPT vaccine |
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Common Cold
[Viral] |
▢ Cause: Rhinovirus
▢ Portal of entry: transmitted via coughing/sneezing, fomites, or person-to-person contact ▢ Signs/symptoms: Sneezing, runny nose, congestion, sore throat, malaise and cough but NO COUGH ▢ Susceptibility: Children acquire colds most often ▢ Diagnosis: Symptoms are usually diagnostic ▢ Treatment: supportive care for symptoms (no vaccine or treatment) ▢ Prevention: Antiseptis and disinfection of fomites ▢ Signs/symptoms: Sneezing, runny |
- the most common although numerous cause colds & the strains are always changing
- if it lasts longer than a week ---> allergies |
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Bacterial Diseases of the Lower Respiratory System
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▢ Lower respiratory organs are usually axenic
▢ When bacterial infection of the lower respiratory system occurs life-threatening illness can result ▢ There are ciliated epithelial cells in trachea ▢ macrophage: phagocytic cells that anilate things in lungs |
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Bacterial Pneumonia
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▢ Pneumonia is inflammation of the lungs accompanied by fluid filled alveoli and bronchioles
▢ Pneumonia can be categorized by the affected region or the organism causing the disease - Lobar penumonia: involves entire lobes of the lungs - Mycoplasmal pneumonia: caused by the bacterium *Mycobacteria* (no cell wall) - Nosocomial pneumonia: pneumonia acquired in a health care setting - Viruses can also cause pneumonia ▢ Bacterial pneumonias are the most serious of the pneumonias and the most frequent in adults |
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Pneumococcal Pneumonia
[BACTERIA] |
▢ Cause: Streptococcus pneumoniae
▢ Virulence factors: Adhesins, capsule, pneumolysin (damages blood vessel in the lungs) ▢ Portal of entry: inhalation ▢ signs/symptoms: fever, chills, congestion, cough, chest pain, and short, rapid breathing ▢ Incubation: 1-3 days ▢ Susceptiblity: immunocompromised individuals ▢ treatment: penicillin is the drug of choice ▢ prevention: vaccination |
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Primary Atypical (Mycoplasmal) Pneumonia
[BACTERIA] |
▢ Cause: Mycoplasma pneumoniae
- Less dangerous; "walking pneumonia" (few weeks) ▢ Virulence factors: adhesion protein ▢ Portal of entry: nasal secretions among individuals in close contact ▢ Signs/Symptoms: atypical symptoms including fever, malaise, sore throat, excessive sweating (mild but persistant) ▢ Incubation period: 1-4 weeks ▢ Susceptibility: high school and college students ▢ Treatment: tetracycline and erythromycin ▢ Prevention: difficult to prevent because individuals can be infective despite lack of symptoms **no cell wall - sometimes confused with virus** |
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Legionellosis
(Legionnaire's disease) [Bacteria, type of pneumonia] |
▢ Cause: Legionella pneumophilia
▢ Portal of entry: inhalation of Leginella-filled vesicles ▢ Signs/symptoms: typical pneumonia symptoms and possible complication of the gastrointestinal tract, CNS, liver and kidneys ▢ Susceptibility: the elderly, smokers, immunocompromised individuals ▢ Diagnosis: presence of legionella or antibodies against the bacterium ▢ Treatment: erythromycin ▢ Prevention: reduce bacterial presence in water ▢ Associated with cooling towers - Philadelphia Conference |
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Tuberculosis
[bacterial, acid fast] |
▢ Cause: Mycobacterium tuberculosis
- (Leprosy as well!) ▢ Mycolic acid present in the cell wall has various effects (waxy coat) ▢ Cord factor is required for mycobacteria to cause disease ▢ Epidemiology: Immunocompromised individuals are most at risk **Leading killer of HIV+ individuals [Diagnosis, Treatment and Prevention] ▢ Tuberculin skin test identifies previous exposure to M. tuberculosis - Doesn't distinguish between active disease, chronic carriers, or those who have been vaccinated ▢ Treatment requires mutli-drug regimen -- *BCG vaccine* - Isoniazide most effective but there are cases of resistance ▢ Prevention includes vaccination in some countries and surveillance of patients to limit spread of disease |
▢ phagocytic failure ---> lives inside macrophages
▢ If no treatment turns into a chronic condition ▢ cough of active TB patient is contagious ▢ can survive out of body b/c waxy coat ▢ treating can be tricky; doesn't produce toxins |
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Inhalation Anthrax
[Bacterial] |
▢ Cause: Bacillus Anthracis
- Not as common as cutaneous anthrax- ▢ Virulence factors: capsule, anthrax toxin ▢ signs/symptoms: intial symptoms resemble a cold or flu but progress to severe coughing, shortness of breath, shock, and death ▢ Diagnosis: Identification of bacteria in sputum ▢ Treatment: various antimicrobials ▢ Prevention: Anthrax vaccine available to military personnel, researchers, health care workers dealing with anthrax patients - cutaneous is not as deadly- |
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Influenza
[Virus] ▢ 25,000 killed every year |
▢ Cause: Influenza types A and B
- Complete virus with 8 pieces of RNA, envelope capsid, and spikes ▢ Hemagglutinin and neuraminidase mutations produce the ever changing array of strains ▢ Mutations occur via two main processes - Antigenic drift: minor - Antigenic shift: major |
[Pathogenesis]
▢ Symptoms of Flu are produced by the immune response ▢ Patients are susceptible to secondary bacterial infections due to damage to lung epithelium - Virus attaches to human lungs [Epidemiology] ▢ Transmission via inhalation of airborne viruses or by self-inoculation - Complications often occur in the elderly, children and those with chronic diseases [Treatment] ▢ Four drugs approved: AMANTADINE, RIMANTADINE, oseltamivir, zanamivir ▢Treatment also involves supportive therapy [Prevention] ▢ Immunization with a multivalent vaccine |
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Histoplasmosis
[Fungal] |
▢ Most common fungal *SYSTEMIC* disease of humans
▢ Cause: Histoplasmosis capsulatum ▢ Portal of entry: inhalation ▢ Signs/symptoms: Dry cough with blood tinged sputum and skin lesions ▢ Epidemiology: endemic to eastern US but also found in parts of Africa and Central and South America ▢ Susceptibilty: Children and those exposed to soil ▢ Diagnosis: Presence of budding yeast in marcophages ▢ Treatment: Amphotercin B - Ergosterol: attacks fungal cell wall ▢ Prevention: Minimize exposure to soil |
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Pneumocystis Pneumonia (PCP)
[Fungal - most effects HIV+ patients] |
▢ Cause: Pneuocystis jiroveci (Previously P. carinii)
▢ Portal of entry: inhalation of droplets containing the fungus ▢ Signs/Symptoms: difficulty breathing, mild anemia, hypoxia and fever ▢ Susceptibility: Immunocompromised patients particularly those with AIDs ▢ Treatment: trimethoprim and sulfamethoxazole (TMP-SMX) ▢ Prevention: Cannot avoid the fungus but maintenance of a healthy immune system limits disease |
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Dental Caries
[Bacterial] |
▢ Cause: Streptococcus mutans
▢ Virulence Factors: Dextran and pili allow biofilm formation on the tooth ▢ Portal of entry: normal flora ▢ Signs/symptoms: holes or pits in the teeth accompanied at times by sensitivity ▢ Susceptibility: Those comsuming high sucrose diets ▢ Diagnosis: Visual inspection and use of x-rays ▢ Treatment: Fill the cavities ▢ Prevention: proper brushing and flossing of teeth and use of fluoridated toothpaste and water |
▢ Semi-anaerobic: likes when mouth is closed ---> grows during sleep
▢ glucan: glue that helps bacteria grow; if not removed can cause plaque that will soften enamel |
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Gingivitis and Periodontal Disease
[Bacterial] |
▢ Cause: Tartar trapped at the base of the teeth triggers gingivitis; *Prophyromonas gingivalis* in anaerobic pockets contributes to periodontitis
▢ Virulence factors: Proteases break down gum tissue ▢ Portal of entry: normal flora ▢ Signs/Symptoms: gums that are swollen, tender, bleeding or bright red ▢ Susceptibility: multiple possible risk factors ▢ Treatment: remove plaque and tartar ▢ Prevention: proper brushing and flossing of teeth and use of fluoride toothpaste and water |
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Peptic Ulcers
[Bacterial] |
▢ Cause: Helicobacter pylori
▢ Virulence Factors: Presence of flagella, adhesins, urease, and other enzymes - Urease: breaks down urea which raises pH- ▢ Portal of entry: fecal-oral transmission likely ▢ Signs/symptoms: primarily abdominal pain, although nausea, vomiting, and weight loss may occur ▢ incubation period: varies ▢ susceptibility: theose colonized by H. pylori ▢ Treatment: *Antimicrobial and acid-blocking drugs* ▢ Prevention: Lifestyle changes to reduce risk |
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Bacterial Gastroenteritis
[Bacterial] |
▢ Inflammation of the stomach or intestines due to the presence of bacteria
▢ Associated with contaminated foods or water and poor living conditions ▢ General features: - Similar manifestations despite different causative agents - Symptoms include nausea, vomiting, diarrhea, abdominal pain and cramps ▢ Dysentry, a severe gastroenteritis, produces loose, frequent stool containing mucus and blood - tissue loss & prevents protein synthesis |
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Cholera
[Bacterial] |
▢ Cause: Vibrio cholerae
▢ Virulence factors: cholera toxin (enterotoxin) ▢ A WBD; ingestion of contaminated water or raw/uncooked seafood ▢ "Rice-water" diarrhea, dehydration - Ion uptake is disturbed - ▢ Treatment: fluid and electrolyte replacement ▢ Prevention: boil water, cook foods thoroughly, avoid raw fruits and vegetables |
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Traveler's Diarrhea
[BACTERIA] |
▢ Cause: Escherichia coli
▢ Produces shiga-like toxin ▢ fecal-oral route ▢ Abdominal cramps, bloody stools, nausea, vomiting ▢ Locals become immune to disease but traveler's get sick |
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Shigellosis
[Bacteria] |
▢ Cause: Shigella
▢ Produces shiga toxin, similar to traveler's diarrhea ▢ fecal-oral ▢ Abdominal cramps, bloody stools, nausea, vomiting |
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Campylobacter Diarrhea
[Bacteria] |
▢ Cause: Campylobacter jejuni
▢ Virulence factors: adhesins, cytotoxins, endotoxin ▢ fecal-oral route; swimming/recreational water ▢ Signs/Symptoms: Abdominal cramps, bloody stools, nausea, vomiting |
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Salmonellosis
[Bacteria - Mild] |
▢ Cause: Salmonella enterica
▢ Contaminated food or water ▢ MILD gastroenteritis symptoms along with fever, headache, muscle pain, malaise ******* Some forms of disease are more serious than others [TYPHOID FEVER] ***** |
[TYPHOID FEVER]
▢ More serious form of infection by salmonella ▢ With complications such as intestinal hemorrhage, perforation, kidney failure, or peritonitis ▢ *SYSTEMIC* ▢ phagocytic failure |
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Bacterial Food Poisoning (Intoxication)
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▢ Cause: Staphylococcus aureus
▢ Toxins from contaminated food cross mucous membranes of the intestinal tract ▢ Nausea, vomiting, diarrhea, cramping ▢ Develops quickly: 4-6 hours |
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LOOK AT SLIDE 337 ABOUT CDAD
Clostridium Difficile-Associated Diarrhea |
▢ gram positive, rod-shaped bacteria
▢ obligate anaerobes ▢ prolonged use of antibiotics ---> disrupts normal flora ▢ Colitis: inflammation of colon; overgrowth causes overflow & damage to colon |
Reseviors for toxigenic CDAD (C.difficile)
▢ 15-70% of healthy neonates (age to 1 year) ▢10-20% of hospitalized patients, especially with antibiotics [NOSOCOMIAL] -Syndromes and complications- ▢ Asymptomatic colonization (most of the time) ▢ Diarrhea (mild to severe) ▢ Colitis +/- pseudomembranes (endoscopy) ▢ Toxic megacolon (radiology) -damage to colon- |
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Viral Hepatitis
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▢ Hepatitis is the inflammation of the liver
▢ Symptoms: jaundice, abdominal pain, fatigue, nausea, vomiting, appetite loss ▢ Host immune responses are responsible for much of the liver damage seen with hepatitis ▢ Cirrhosis ▢ Diagnosed by presence of excess liver enzymes in blood ▢ Presence of antibody in blood ▢ For most cases: No vaccine, no treatment ▢ Some cases may cause liver cancer |
LOOK AT SLIDES 340-341
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Hepatitis B
[Viral] |
▢ Also called serum hepatitis
▢ Some people have chronic disease ▢ HBV is associated with liver cancer ▢ Recombinant produced vaccine available ▢ Doesn't kill you, but chronicly can make you feel sick ▢ Modes of transmission: - Sexual: STD - Parental: scratches, injections -prenatal: mother to baby |
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Concentration of Hepatitis B Virus in Various Body Fluids
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[High]
▢ Blood ▢ Serum ▢ wound exudates *drug use* [Moderate] ▢ Semen ▢ Vaginal fluid ▢ saliva [Low/Not detectable] ▢ urine ▢ feces ▢ sweat ▢ tears ▢ breastmilk |
[Risk factors for Acute Hepatitis B]
▢ Heterosexual - 41% ▢ Injecting drug use - 15% [Geographic Distribution of Chronic HBV Infection] ▢ Places that are HIV stricken have HBV problems ▢ Prevalence: S. America, SE Asia, Sub-saharan Africa |
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Hepatitis C
▢ Highest chronic infection in the US |
▢ Persons ever infected - 1.8% 3.9 million (3.1-4.8)
▢ Persons with chronic infection - 2.7 million (2.4-3.0) ▢ Of chronic liver disease - HCV-related ▢ Deaths from chronic disease/year 8,000-10,000 [Features of Hepatitis C virus Infection] ▢ Incubation Period: Average 6-7 weeks; Range 2-26 weeks ▢Chronic Infection: 75-85% ▢ Chronic hepatitis: 70% |
[Risk factors for Acute Hepatitis C]
▢ Injecting drug users - 38% ▢Socioeconomic Status - 44% [Transmission of HCV] ▢ Percutaneous ▢ Permucosal ▢ Four times more common than HIV ▢ Prevalence 60-90% after 5 years ▢ Hemophilia highest prevalence |
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Protozoan Diseases of the Intestinal Tract
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▢ Few protozoans cause gatroenteritis infections
▢ oocyst: present in feces ▢ Two forms: - Cyst: transmission, resistant - trophozoic: growing |
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Giadiasis
[Protozoa] |
▢ Cause: Giardia intestinalis (formerly G. lambia)
▢ Portal of entry: Ingestion of infectious cyst ▢ Signs/symptoms: greasy, frothy, fatty diarrhea with terrible odor, abdominal distention, cramps ▢ Susceptibility: Everyone, hikers and campers who drink contaminated water ▢ Treatment: Mertonidazole for adults; Furazolidone for children ▢ Prevention: Good hygiene and avoid consuming untreated water |
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Crytosporidiosis
[Protozoa] |
▢ Cause: Cryptosporidium parvum
▢ Portal of entry: consumption of water contaminated with oocysts; fecal-oral transmission can also occur ▢ Signs/symptoms: severe watery diarrhea accompanied by headache, muscular pain, cramping, nausea, fatigue; life-threatening complications can occur ▢ Susceptibility: immunocompromised individuals are most at risk for severe disease ▢ Diagnosis: Presence of oocysts in stool ▢ Treatment: Supportive care for symptoms ▢ Prevention: good hygiene and avoid consuming contaminated water or food |
▢ Has low ID50 - meaning it doesn't take much of a population to make you sick - only takes about 10-20 minutes
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Amebiasis
[Protozoa] -more dangerous than Giadiasis & Cryptosporidiosis- |
▢ Cause: Entamoeba histolytica
▢ Portal of entry: ingestion of contaminated food and water ▢ signs/symptoms: - luminal amebiasis - asymptomatic; - invasive amebic dysentary - symptoms include diarrhea, colitis, appendicitis - Invasive extraintestinal amebiasis - necrotic lesions in the liver, lungs, spleen, kidneys, or brain ▢ Incubation period: 6-20 days ▢ Susceptbility: person in regions in poor sanitation ▢ Treatment: oral rehydration and antiamebic drugs ▢ prevention: avoid contaminated food and drugs *** Can be SYSTEMIC AND CAUSE DAMAME*** *** Can cause organ failure*** |
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Bacterial Urinary Tract Infections
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▢ Bacteria can infect all regions of the urinary tract
▢ Cause: E. coli (Kleseilla) (Proteus) ▢ Frequent, painful urination; urine may be cloudy with foul odor Susceptibility: Females |
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Streptococcal Acute Glomerulonephritis
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▢ Caused by depositing Ag-Ab complex in the glomeruli of the kidneys
- Causes inflammation in the glomeruli and nephrons (glomerulonephritis) - Produces hypertension and lower urine output ▢ Young patients usually recover but irreversible kidney damage can occur in adults (usually young boys) ▢ Phenol & lactation used for detection + <25 means no infection + 25-50 presumptious + 50< has infection ▢ Inc. pH - pink; Dec. pH - yellow |
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Staphylococcal Toxic Shock Syndrome (TSS)
[Nonvenereal Disease] |
▢ Cause: Staphylococcus aureus strains
▢ TSS toxins ▢ via Vaginal irritation ▢ sudden high fever, vomiting, rash, low BP |
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Bacterial Vaginosis
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▢ Cause: Gardnerella vaginalis
▢ Decline in the lactobacilli population results in an increased vaginal pH - decrease in good bacteria ▢ fecal-oral route ▢ white vaginal discharge with a "fishy" odor |
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Candidiasis, Yeast Infection
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▢ Cause: Candida albicans
▢ Via mucous membranes by normal flora ▢ White curdlike discharge, burning, itching, painful intercourse ▢ Susceptiblity: women on antimicrobial drugs, immunocompromised individuals ▢ prevention: avoid moisture in the genital area |
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