unit 9 Flashcards
crust rash
dried fluids from a lesion on the skin surface
papule rash
small raised skin lesions
bulla rash
fluid-filled skin lesion larger than 1 cm
pustule rash
raised, pus-filled skin lesions
vesicle rash
small fluid-filled lesions smaller than 1 cm
ulcer rash
break in the skin
macule rash
flat discoloured lesion
wheal rash
swollen, inflamed skin that itches and burns
different diseases caused by s. aureus
folliculitis, furuncles, carbuncles, scalded skin syndrome, impetigo
features of folliculitis
signs: bumps, pimples that itch, red/pus-fill
virulence factors: leukocidins which kill WBCs
transmission: opportunistic infections (sweat, skin injury, ingrown hairs, tight clothing, shaving)
entry: parenteral
detection: skin inspection
treatments: self-limiting, topical antibiotics
features of furuncles
signs: larger lesions
VF: leukocidins kill WBC
transmission: direct contact, opportunistic infection
entry: parenteral
detection: skin inspection
treatments: self-limiting, topical
features of carbuncles
signs: deeper lesions
VF: leukocidins kill WBC
transmission: direct contact, opportunistic infection
entry: parenteral
detection: skin inspection, culture swabs to verify ID
treatments: lesions drained; antibiotics
features of scalded skin syndrome
signs: skin redness and peeling, affects mainly newborns
VF: exotoxins leading to sign and symptoms
transmission: opportunistic infection
entry: parenteral
detection: blood tests, culture swabs
treatments: IV antibiotics
features of impetigo
signs: formation of vesicles, pustules, bullae around the nose and mouth; later these rupture and form crusts
VF: none
transmission: direct contact; opportunistic infection
entry: parenteral
detection: visual inspection
treatments: topical or oral antibiotics
which disease has an co-infection and what is it
impetigo s. aureus w/ s. pyogenes
what disease is caused by s. pyogenes
necrotizing fasciitis
features of necrotizing fasciitis
signs: rapid death in connective tissue
VF: capsule, M-protein - both to avoid phagocytosis, bacterial protease to destroy host tissues, exoenzymes: streptolysin, hyaluronidase, streptokinase
transmission: opportunistic infection
entry: parenteral, sometimes unknown
detection: visual inspection, culture swab for ID
treatment: debridement (removal of infected tissue), amputation, IV antibiotics
etiology and features of acne
cutibacterium acnes; (gram-positive, aerotolerant)
signs: papules, pustules
transmission: clogged pores leading to comedones (whiteheads & blackheads; non-inflammatory); this leads to infection by c. acnes & digests lipids in sebum and secretes free fatty acids leading to lesions
entry: opportunistic infection
detection: visual
treatments: topical agents, antibiotics (erythromycin), acne creams, hormones, phototherapy & laser therapy to reduce oil build-up
herpes simplex virus - type 1
cold sores
signs: blisters around the lip region; eventually break open and crust, infection is latent and recurs upon stress or environmental conditions
transmission: direct contact during active infection
entry: skin
detection: visual infection; lab testing
treatments: topical meds to manage symptoms
herpes simplex virus - type 2
genital herpes
signs: blisters around genitals; eventually break open and crust, infection is latent and recurs upon stress or environmental conditions
transmission: direct contact during active infection
entry: skin
detection: visual infection; lab testing
treatments: antiviral meds to manage infection
different diseases of candidiasis
cutaneous, vaginal, thrush
cutaneous candidiasis features
etiology: candida spp.
signs: red, itchy rash on skin folds, nails
transmission: opportunistic infection
entry: skin
detection: visual
treatment: n/a
vaginal candidiasis features
etiology: candida spp.
signs: vaginal itching, thick yellow/white discharge, odor
transmission: opportunistic infection, following treatments that disrupt normal flora, sexual transmission
entry: skin
detection: visual
treatments: anti-fungal creams
thrush candidiasis features
etiology: candida spp
signs: white patches in the mouth, possible bleeding
transmission: opportunistic infection
entry: skin
detection: visual
treatments: n/a
describe the protective features of respiratory system
mucus traps microbes and prevents them from colonizing, ciliary escalator dislodges, and propels mucus and trapped microbes out of the epiglottis, alveolar macrophages stay in lower respiratory, IgA antibodies
typical members of pathogenic organisms in upper respiratory
streptococcus, haemophilus, neisseria
strep throat features
etiology: streptococcus pyogenes (gram-positive)
signs: high fever, dark swollen tonsils, petechaie (red bumps) rash on soft/hard palate, swollen lymph nodes
VF: hyaluronidase, collagenase, streptokinase, streptolysins
complications: acute rheumatic fever and acute glomerulonephritis
transmission: direct contact or droplet transmission through coughing and sneezing
entry: mucus membranes
detection: immunoassay followed up by culture swab for ID
treatments: antibiotics
bacterial pneumonia: streptococcus pneunomiae
gram-positive
signs: lung infections, leading to inflammation in the alveoli, painful breathing
VF: capsule to prevent phagocytosis, contains other factors to promote disease progression
transmission: direct contact; droplet transmission
entry: mucus membrane
detection: culture swabs for ID
treatments: antibiotics
vaccine: yes - conjugate vaccine
bacterial pneumonia: haemophilus influenza
gram-negative
signs: lung infections, leading to inflammation in the alveoli, painful breathing
VF: capsule to prevent phagocytosis
transmission: direct contact; droplet transmission
entry: mucus membrane
detection: culture swabs for ID
vaccine: yes - conjugate vaccine
bacterial pneumonia: mycoplasma pneumoniae
no cell walls, disease tends to be more mild
signs: lung infections, leading to inflammation in the alveoli, painful breathing
VF: n/a
transmission: direct contact; droplet transmission
entry: mucus membrane
detection: culture swabs for ID
vaccine: no
diseases of the respiratory system
bacterial causes: strep throat, bacterial pneumonia, tuberculosis, pertussis - whooping cough, viral causes: common cold, influenza, viral pneumonia, measles, chickpox
tuberculosis etiology
mycobacterium tuberculosis (gram-positive)
tuberculosis features
signs: chronic cough, chest pain, coughing up blood/sputum
VF & pathogenesis: waxy mycolic acid protects against digestion after phagocytosis, an inflammatory response is initiated and more macrophages are recruited, small lesions called tubercle are formed, eventually these tubercules rupture allowing the bacteria to spread, most lesions will heal to form calcified Ghon complexes, complications: chronic disease (can last months to years) and many drug resistant strains are present
transmission: direct contact; droplet
entry: mucus membranes
treatments: antibiotics
vaccine: yes - attenuated vaccine
etiology of pertussis
bordetella pertussis (gram-negative)
signs of pertussis
long period of severe coughing leading to a “whoop” sound during cough
three stages of whooping cough
cararrhal - which is relatively mild
paryxosymal - which leads to uncontrollable coughing spasm
convalescence - which is a long recovery period where patients experience a chronic cough
VF & pathogenesis for pertussis
uses an adhesion for adherence, A-B extoxins called the pertussis toxin known to enhance inflammatory responses, cytotoxins that damages ciliated epithelial cells leading to increased mucus production
pertussis: entry, detection, treatments, vaccine
droplet, mucus membrane, culture swab for ID, self-limiting & antibiotics, yes toxoid vaccine
common cold features
etiology: rhinoviruses, coronaviruses, adenoviruses - these viruses tend to replicate in conditions slightly lower than body temp
signs: runny nose, sore throat, coughing, no fever
pathogenesis: irritation of mucosa leading to an inflammatory response
transmission: direct; droplet
entry: mucus membrane
treatments: self-limiting
features of influenza
eti: influenza virus
signs: fever, chills, bodyaches
VF & pathogenesis: 2 spike proteins - hemagglutinin (H) used for viral entry & neuraminidase (N) used for viral exit
transmission: direct contact; droplet
entry: mucus membrane
treatments: self-limiting; antivirals in more severe cases
vaccine: seasonal flu vaccine - inactivated
antigenic drift
result of point mutations causing slight changes in the spike proteins - requires new vaccines to be developed every year
antigenic shift
result of large changes due to gene reassortment - can occur when a host is infected with multiple influenza viruses - leads to formation of new influenza viruses
viral pneumonia features
eti: adenoviruses, influenza viruses, parainfluenza viruses, respiratory syncytial viruses
signs: range from mild cold-like symptoms to severe pneumonia, depending on the causative virus
measles features
eti: measles virus
signs & pathogenesis: virus
enters the respiratory system, then spreads to the bloodstream (viremia) and eventually forms a characteristic macular rash on the skin, the rash starts first on the face and later spreads to the extremities, other signs includes high fever & Koplik’s spots
transmission: direct contact, droplet, airborne
entry: mucus membranes
detection: based on signs, presence of Koplik’s spots
treatments: self-limiting, supportive care to manage symptoms
vaccine: live attenuated vaccine
chickpox features
eti: varicella-zoster virus
signs & pathogenesis: after exposure, the virus spreads through the bloodstream & eventually leads to a pustular rash on face, which later progresses to the trunk, eventually the lesions burst forming crusts, the virus moves along the sensory nerves to the dorsal ganglia in the spinal cord
transmission: direct, droplet
entry: mucus membranes
detection: based on signs
treatments: self-limiting, supportive care
vaccine: attenuated vaccine
connection between chickpox and shingles
virus can become reactivated due to stress, aging
virus then moves along the sensory nerves resulting in painful lesions
shingles itself is not contagious, but a non-exposed person can develop chickpox as a primary infection if in contact with a person with shingles
shingles can be treated with antivirals
vaccine available - same vaccine as chickpox
bacteremia
presence of bacteria in the blood
septicemia
bacteria reproducing in the blood
viremia
presence of viruses in the blood
toxemia
presence of toxins in the blood
systemic inflammatory response syndrome (SIRS)
inflammation so severe that it damages host tissues and organs more than the actual infection
can lead to sepsis: excessive production of excess cytokines leading to damaging inflammation
ischemia
reduced blood flow to tissues
necrosis
tissue death
lymphangitis
inflammation of the lymphatic vessels
diseases of the circulatory system
toxic shock syndrome, gas gangrene, infectious mononucleosis, burkitt lymphoma, hantavirus pulmonary syndrome, AIDS, lymphatic filariasis
toxic shock syndrome features
eti: staphylococcus aureus (gram-positive)
signs: vomiting, diarrhea, fever, hypotension & erythematous rash
VF: production of TSST-1 (superantigen exotoxin), leads to excessive release of cytokines leads to drop in blood pressure and formation of blood clots
transmission: occurs through localized or systemic wounds
entry: parenteral
detection: clinical signs, serologic tests, toxin detection
treatments: debridement of infected tissues, vasopressors to increase blood pressure and antibiotics
gas gangrene causative organism
clostridium perfingens (gram-positive, endospore-forming)
gas gangrene features
signs, VF, pathogenesis: pathogen is obligate anaerobe, so toxins produced are there to decrease oxygen levels in local environments, several toxins leads to ischemia and necrosis, gas produced through fermentation
transmission: trauma wounds, damage to blood vessel
entry: parenteral
detection: rapid spread of myonecrosis, pain, gas pockets
treatments: debridement, amputation, hyperbaric oxygen therapy, antibiotics
infectious mononucleosis and burkitt lymphoma causative organism
epstein-barr virsu
infectious mononucleosis features
signs & pathogenesis: leads to pharyngitis, fever, fatigue continuing from months
transmission: direct contact
entry: mucus membranes
detection: serological tests
treatment: self-limiting
burkitt lymphoma features
signs: rapidly growing tumours, more prevalent in children & Africa
transmission & entry: n/a
detection: biopsy
treatments: chemo
hantavirus pulmonary syndrome features
eti: hantavirus
signs &pathogensis: starts off with flu symptoms, progresses to pulmonary edema and hypotension
transmission: airborne: zoonotic
entry: mucus membranes
detection: n/a
treatments: supportive care with limited antivirals
lymphatic filariasis
eti: wuchererua bancrofti (nematode)
signs & pathogenesis: targets & blocks lymphatic vessels, leads to edema & fibrosis, causing extreme swelling
transmission: vector biological (mosquitoes transfer larvae)
entry: parenteral
treatment: prevention = sanitation, mosquito control & anti-helminthic medication
peptic ulcers causative organism
helicobacter pylori
peptic ulcer features
signs: nausea, lack of appetite, bloating, burping, weight loss, dark stools
transmission: direct contact or contaminated water
entry: mucus membranes
detection: breath test, radiolabeled urea, biopsy
treatments: antibiotics
VF & pathogensis of peptic ulcers
bacterium tolerates acidic environment of stomach, VF includes production of urease, which can lead to the production of ammonia which neutralizes the stomach acids, the infection damages the lining & can lead to stomach perforation and increased risk of stomach cancer
staphylococcal food poisoning features
VF & pathogenesis: typically only intoxication, produces heat-stable enterotoxins which act as a superantigen
transmission: vehicle” consumption of raw meat, dairy productions, salty foods
entry: mucus membranes
detection: not typical
treatment: oral rehydration therapy
shigellosis etiology
shigella spp. (gram negative)
shigellosis features
signs: cramps, fever, watery diarrhea
VF & pathogensis: organism is invasive & moves to neighbouring cells, shiga toxin produced leads to hemorrhaging, complications: ulceration of mucosa, dehydration, rectal bleeding, HUS
transmission: direct contact & vehicle transmission (fecal-oral)
entry: mucus membranes
detection: stool sample
treatments: antibiotics
salmonellosis etiology
salmonella spp. (gram-negative)
salmonellosis features
VF & pathogensis: invasive, no movement to other cells, can persist in macrophages, can enter bloodstream & persist in body, making person carrier, can be infection or intoxication
transmission: vehicle transmission - consumption of contaminated food
entry: mucus membrane
detection: stool sample & serotyping
treatments: oral rehydration therapy, antibiotics in severe
EPEC (enteropathogenic E. coli)
gram negative
signs & VF: leads to vomiting & diarrhea, “travelers diarrhea”, can lead to severe dehydration
transmission: vehicle transmission
entry: mucus membranes
detection: n/a
treatments: oral rehydration, antibiotics
EHEC (enterohemorrhagic e. coli)
gram negative
signs & VF: more severe, produces shiga-like toxin
transmission: vehicle transmission
entry: mucus membranes
detection: presence of toxin in food or stool
treatments: oral rehydration - NO antibiotics (endotoxin produced)
cholera features
eti: vibrio cholera (gram-negative)
signs: severe diarrhea (rice water stools)
VF: motile produces A-B exotoxins, leads to activation of chloride channels which leads to loss of ions followed by water
transmission: vehicle transmission - fecal oral
entry: mucus membranes
detection: stool sample
treatments: oral rehydration, antibiotics
c. difficile features
eti: clostridioides difficile (gram positive, endospore forming
VF: produces 2 toxins leads to diarrhea, dehydration, loss of appetite & abdominal pain
transmission: healthcare-associated infection, opportunistic infection
entry: mucus membranes
detection: stool sample
treatments: oral rehydration, fecal transplants
Giardiasis
etiL Giardia lamblia (protozoan)
Signs: Diarrhea, nausea, stomach cramps, gas, dehydration (lasts 2-6 weeks);
VF: Protist attaches to the intestinal mucosa using an adhesive disk, which blocks the absorption of nutrients
complications: development of chronic infections that are resistant to treatment
transmission: vehicle transmission (ingestion of contaminated food or water (especially during camping
season) , Direct contact
entry: mucus membranes
Detection: stool sample examination looking for cysts and trophozoites
Treatments Anti-protozoan medication
Prevention: filtration of water to remove cysts (boiling water is not effective)
meningitis
inflammation of the meninges
encephalitis
inflammation of the brain tissue
bacterial meningitis: neisseria meningitidis (gram-negative) VF:
Produces endotoxin, factors for attachment, capsule to avoid phagocytosis, and produces enzymes to avoid the immune system Leads to a characteristic petechial rash
Children and young adults more susceptible (before vaccine or booster) Complications: rapid progression leading to sepsis, multiple organ failure and death
bacterial meningitis: Streptococcus pneumoniae (gram-positive) VF:
Also contains several virulence factors for attachment and triggering inflammation; has a capsule
Children prior to receiving
the vaccine are more
susceptible
Complications: can lead to
septicemia
bacterial meningitis: Haemophilus influenzae
(gram-negative) VF:
Also contains several virulence factors to trigger inflammation, adherence, invasion, as well as a capsule
transmission of bacterial meningitis
Pathogens gain access to bloodstream after trauma, production of toxins, or spread
from respiratory tract (direct contact or droplet transmission)
In the bloodstream, the presence of pathogens leads to inflammation, which makes the CNS more susceptible to infection
entry, treatments, vaccine for bacterial meningitis
mucus membranes, antibiotics, conjugate vaccine
detection of neisseria men.
gram-staining of CFS ( negative w/ coffee bean morphology)
detection of streptococcus pneumoniae
gram-staining CFS
cryptococcosis (fungal meningitis) eti:
Cryptococcus neoformans
Cryptococcosis (fungal meningitis) features
Virulence factors; pathogenesis; signs/symptoms: has a thick capsule used to prevent phagocytosis
Transmission: vehicle transmission where the pathogen is found in soil and
aerosolized pigeon droppings
entry: mucus membranes (respiratory system)
Detection: urine sample
Treatments: Anti-fungal drugs
Amoebic meningitis eti:
Naegleria fowleri (protozoan)
Amoebic meningitis features
virulence factors; pathogenesis;
signs: parasite in trophozoite form will enter through the nasal passages and ultimately makes its way to the CNS
transmission: submersion of head while swimming in freshwater
entry: mucus membranes (nose)
detection: Direct observation of cerebrospinal fluid
Treatments Anti-protozoan drug coupled with therapeutic hypothermia (works only if infection is caught early)
Tetanus eti:
Clostridium tetani (gram-positive, obligate anaerobe, endospore-forming
tetanus feaures:
signs, virulence
factors; pathogenesis: produces an exotoxin called tetanospasmin, which prevents the release of the neurotransmitter GABA, which is necessary for muscle relaxation
transmission: direct contact through wounds, vector biological transmission through animal bites
entry: parenteral
treatments: assisted breathing, wound debridement, antibiotic therapy, anti-toxins
Vaccine Toxoid vaccine
localized & generalized tetanus
• localized tetanus affects only the muscle groups at the site of injury, leading
to muscle spasms in that area
• generalized tetanus is spread throughout the body, leading to lockjaw,
uncontrollable and sudden muscle spasms (characteristic arched back), and
eventually progressing to the respiratory system (leading to death)
Botulism eti
Clostridium botulinum (gram-positive, obligate anaerobe, endospore-forming
Botulism VF:
Produces an exotoxin called botulism toxin, this exotoxin prevents the release of the neurotransmitter acetylcholine which prevents muscle contraction (progressive flaccid paralysis)
signs and symptoms start with blurred vision, dropping eyelids, abdominal cramps, nausea,
vomiting, diarrhea; in more severe cases, the respiratory system is affecting leading to death
Medical usage of toxin: used to treat various medical conditions such as cerebral palsy,
multiple sclerosis, Parkinson’s disease; also used for cosmetic purposes to remove wrinkles,
prevent excessive sweating
Botulism features
transmission; entry
foodborne botulism: foodborne vehicle transmission (honey, improper canning
procedures, etc.); mucus membranes (GI system) – occurs in infants or
immunocompromised adults
inhalation botulism: airborne vehicle transmission; mucus membranes (respiratory
system)
iatrogenic botulism: direct contact transmission, parenteral (rare event after
therapeutic or cosmetic use of toxin)
Treatments Anti-toxins
Rabies
Eti: Rabies virus
Signs: furious rabies, where the individual shows signs and symptoms such as agitation,
hydrophobia, and excessive salivation
paralytic rabies, where the muscles progressively become paralyzed leading to coma
Pathogenesis: after entering the body, the incubation period can be quite long, ranging over
weeks - years, as the virus replicates, it moves along the neuron, once it reaches the brain, it disrupts normal neurotransmitter function (e.g., acetylcholine, GABA, glycine), eventually the virus can move out to other tissues such as salivary glands and nasal cavity
transmission: vector biological transmission through animal bites
entry: parenteral
Treatments: vaccines (inactivated vaccine) due to slow progression of pathogen, antibodies are also administered
Cystitis (urinary tract infection)
Eti: various, including E. coli, Proteus vulgaris, Pseudomonas aeruginosa, Klebsiella pneumonaie
Signs and
symptoms: Dysuria (painful urination), pyuria (pus in urine), hematuria (blood in urine),
bladder pain
Pathogenesis: can progress to pyelonephritis if not treated
transmission: Non-communicable: typically a result of fecal contamination, irritants from radiation
treatment, or hygiene sprays
Detection Urine culture
Treatments Antibiotics
Kidney infections
Etiology Same as cystitis
Signs and
symptoms: Back pain (kidney area), fever, nausea/vomiting
Pathogenesis Can progress to pyelonephritis if not treated
transmission:
Non-communicable: spread from cystitis, or from a bacterial infection in the bloodstream
Detection Urine culture and urine testing
Treatments Antibiotics
Gonorrhea
Etiology Neisseria gonorrhoeae (gram-negative bacterium)
Signs:
Typically asymptomatic but if present:
• Males: burning during urination and discharge
• Females: pelvic pain and discharge
VF: contains a variety of virulence factors which includes fimbriae and production of
endotoxins
Complications: can spread throughout the body leading to bacteremia and affect different
organs; in females, can spread to the endometrium and fallopian tubes leading to PID
transmission: Direct contact (sexual contact) entry: mucus membranes (urogenital system)
Detection Culture swabs from infected areas
Treatments Antibiotics (with increased strains that are antibiotic-resistant)
Syphilis stages
- Primary stage: Formation of a painless lesion called a chancre
- Secondary stage: Characterized by a skin rash that takes on many forms
o After the secondary stage, the bacterium can enter a latent phase
• Tertiary stage: Formation of granulomatous lesions called gummas
o These can cause severe tissue damage in locations such as the cardiovascular or the nervous system
Syphilis
Etiology Treponema pallidum (gram-negative spirochete
signs, VF: most of the tissue damage is caused by the production of lipoproteins by the bacterium, allowing it to cause damaging inflammation to enhance further invasion
transmission: direct contact (sexual contact)
entry: mucus membranes (urogenital system)
Detection Microscopy or culture swabs from lesions
Treatments Antibiotics
Human Papillomas
Etiology: Human Papillomavirus (non-enveloped DNA virus)
signs, VF: some serotypes lead to genital warts – irregular, soft, pink growths, Some serotypes can lead to cancer such as oropharyngeal, cervical, anal, vaginal, vulvar, penile
transmission: direct contact (sexual contact)
entry: mucus membranes (urogenital system)
Detection Testing is done only for women – pap smears (looking for cells with enlarged nuclei – koilocytes)
Treatments Self-limiting:
Genital warts – removal or use of topical medications (interferons)
Cancers – biopsy for confirmation and then chemotherapy
Vaccine Subunit vaccines for serotypes that cause cancer (Gardasil and Cervarix) for both boys and
girls
