Microbio Exam 5

• Mucous memb.
• a. wet, not as tough as skin
• b. often low pH
• c. Normal flora
• d. macrophages, IgA
• e. mucous

• a. Gm+ cocci in clusters
• b. facultative metabolism
• c. colonies 2-3mm. opaque with non-water soluble golden pigment +/- hemolysis

• d. vir and inv factors numerous (examples
• 1. coagulase (clots fibrinogen)
• 2. enterotoxins (food poisoning)
• 3. hyaluronidase (breaks down extracellular matrix)
• 4. cytotoxins (kill WBC's)
• 5. exfoliative toxins (skin peeling)
• 6. others
• 7. and other staph species are normal flora of skin, GI tract, oropharynges and urogenital tract

• A. Wound infection
• 1. autoinoculation or from fomites or hands
• 2. Coagulase + or - staph
• 3. can be MDR staph (eg. MRSA)
• 4. may require aggressive antibiotic treatment
• 5. can cause systemia
• B. in-dwelling catheter infection
• 1. catheters allow constant contact tof skin to open tissues leading to infection
• 2. coagulase - staph, skin normal flora
• 3. often causes low grade bacteremia

• furunucles: infections which start in hair follicle (rare cause of systemia)
• carbuncle: infection is larger, deeper and more serious (must drain and treat with antibiotic)
• pustules: a small lesion filled with pus (usually self-lmiting with drainage)

• 1. Scalded skin syndrome
• a. neonates
• b. staph stain with exfoliative toxin
• c. erythema that starts in mouth and covers body in 2 days
• d. top layer of skin peels
• e. neonate recovers in about 2wks when IR kicks in
• f. rare secondary systemia can kill in 36 hrs.

• 2. Impetigo (children, esp. boys)
• a. staph strain with hyaluronidase vir. factor
• b. superficial, rapidly spreading, contagious skin lesions, esp. of face.
• c. heals without scarring
• d. neonatal version: bullous impetigo
• e. also Streptococcus pyogenes

• 1. TSST-1 toxin producing strains of S. aureus
• 2. systemia or from super absorbent tampons (no longer on the market)
• 3. entire body desquamation
• 4. rapidly fatal systemic shock if not treated
• Staph. aureus an also cause endocarditis, systemia and food poisoning (later)

• a. autoinoculation from skin, GI or nasopharyngeal normal flora
• b. fomites, droplet nuclei and hands cause many nosocomial infections

• a. Multiple drug resistance (MDR) is common (due to bacteriophage transduction?)
• b. Methicillin resistant S. aureus (MRSA) now common in hospital environment and becoming common outside hospital.
• c. Vancomycin resistant S. aureus (VRSA) has now been detected

• a. Strept pyogenes and other streptococci cause a variety of diseases.
• d. S. pyogenes can be carried transiently, in low numbers, with the normal flora in the nasopharynges
• e. disease spread is most commonly from transient carriers in the form of droplet nuclei, hands, fomites

• 1. introduction of mo into broken skin
• 2. pustule develops, usually self-limiting

• 1. secondary to strept throat or pyoderma
• 2. skin raised, inflamed, painful, low grade symptoms of systemia

• 1. secondary to streopt throat or pyoderma
• 2. a deeper infection than erysipelas
• 3. skin not raised,but is inflamed, painful, symptoms of systemia
• 4. many organisms can cause cellulitis

• 1. introduced through skin break
• 2. initially like cellulites, spreads to muscle and fat and degrades theses tissues with enzymes (vir factors)
• 2. rapidly fatal systemia develps w/o aggressive treatment

• Small Pox
• Dermatomycosis

• many mo's can cause burn infections
• 1. coliforms (Gm-, facultative rods from GI)
• 2. Staph and Strep
• 3. Most common and dangerous: Pseudomonas aeruginosa

• 1. Gm-, aerobic rod
• 2. found in water, soil, sometimes as GI normal flora
• 3. extremely antibiotic and disinfectant resistant
• 4. an opportunist but once it starts, a very serious infection ensues
• 5. often makes blue and green pigments
• 6. makes a wide variety of vir and inv factors that are very good at breaking down tissue and spreading the infection

• 1. autoinoculation or introduction from environment (soil, water, disinfectants, flowers, air, soapy water, hands)
• 2. mo divides rapidly in weepage from burns
• 3. hydrolytic enzymes allow easy tissue invasion
• 4. fatal systemia, pneumonia follows (2-4wks)

• 1. strict isolation/aseptic procedures to prevent infection
• 2. antibiotic treatment difficult (combination therapy)

e. Pseudomonas is also noted for Cystic Fibrosis pneumonia.

• eyelid
• conjuctiva
• cornea

• 1. cornea/sclera are tough walled
• 2. tears wash away mo's
• 3. tears contain lysozyme
• 4. mucous entraps mo's
• 5 IgA is likely present

• a. Obligate intracellular bacteria
• b. causes a conjuctivitis called Trachoma
• c spread by poor sanitation, flies, and the rubbing of eyes
• d. highly contagious
• e. lack of treatment leads to abraion of cornea by eyelid/lashes that then causes blindness (common cause of blindnes in 3^rd world)

• a. Gm- intracellular bacteria
• b. causes a disease in neonates called gonococcal conjuctivitis
• c. infection occurs during vaginal birth in a mother with gonorrhea
• d. lack of treatment leads to blindness
• e. neonates are given prophylactic antibiotic eye drops at birth to prevent

• a. Gm- small rods
• b. causes a disease called contact conjuctivitis or pinkeye
• c. spread by poor sanitation, flies and the rubbing of eyes
• d. highly contagious

• infections caused by overly long term use of soft contact lenses
• several different viral conjunctivitis'
• protozoal eye infection caused by ancanthamoeba keratits

• Closed system
• 1. oxygenates tissues
• 2. eliminate CO₂
• 3. remove wasts from tissues and deliver them to spleen and kidneys
• 4. provide mobility to immune system, hormones and other chemical signals
• 5. maintain temp homeostasis

• (open system)
• 1. pick up lymph from interstitial spaces
• 2. clear lymph before it is returned to circ.
• 3. system has no pump

• 1. sterile
• 2. 1^st, 2^nd and 3^rd levels of immunity
• 3. filtration of lymph by lymph nodes and blood by spleen

• a. slow onset of symptoms: fever, weakness,heart murmur
• b. caused by oral streptococci and others from infections throughout the body (e.g. tooth infection, tonsillectomy, body piercings, gynecological exam, teeth cleaning, flossing or even brushing teeth)
• c. often patient has a previous lesions of the heart which provide tissue for the bacteria to entangle in (e.g. causes include scarlet fever, syphilis, previous SBE or heart deformities)
• d. slowly fatal if not treated (long term antibiotics)

• 1. imaging of mass in hearat
• 2. blood culture
• a. draw blood into broth filled bottle, incubate
• b. requires many bottles because: unknown mo metabolic requirements (O₂, nutrients), interfereing chems, antibiotics, few mo's in blood, etc

• a. initial symptosm: fever, chills, weakness (i.e. nonspecific type symptoms)
• b. rapid onset, later symptoms: decreased cardiac output and microcoaagulation of peripheral blood (rapidly fatal)
• c. usually caused by S. aureus
• d. parenteral drug users have a milder form of this disease that is more like SBE

• 1. bacteria growing in blood stream
• 2. often septicemia is secondary to other problems: patient is immuno-compromised, pneumonia, TB, burn patient, syphilis, invasive GI bacteria, gangrene, cellulitis

fever and malaise, then decrease in cardiac output, decrease in bp, decrease in temp, acute systematic inflammation (septic shock) and deat

• a toxemia leading to systemic shock
• 1. lipid A of LPS of Gm- cell membrane are present in Gm- systemia
• 2. treatment with antibiotics leads to release of more endotoxins, often resulting in systemic shock and death

• a. bites can introduce mo's directly into the blood stream or tissues
• b. mo's can be pathogens carried by the animal (e.g. rabies, malaria, plague)
• c. mo's can be part of oral normal flora which can also be very dangerous (e.g. human)
• d. bites often cause bacterial systemias

• a. Yersinia pestis
• 1. short, Gm- rod
• 2. facultative
• b. Main vir factor: antiphagocytic capsule
• c. transmission: flea bite or droplet nuclei from pneumonia

• 1. flea bites infected rodent (usually rat or ground squirrel)
• 2. bacilli multiply in gut of flea
• 3. gut becomes blocked
• 4. flea bites host bug gut is blocked resulting in regurgitated blood back into the bite
• 5. mo's carried to regional lymph nodes of of new host
• 6. mo's not phagocytized and multiply in node
• 7. infected node becomes pus filled, swollen: bubo
• 8. systemia follows with generalized symptoms plus the buboes
• 9. systemic shock precedes death (nearly 100% fatal at this stage)
• 10. takes 3-5 days

treatment: prompt antibiotics (before the systemia is too severe)

Vector was from ground squirrel

pneumonic plague and the black death in Europe in the 14th centrury

• a. Franciella tularensis
• 1. Gm- coccobacillus
• 2. aerobic, obligate intracellular
• 3. vir: antiphagocytic capsule

mo's is found in a variety fo rodents, birds and ticks

• a. typhoid-like tularemia from eating undercooked infected rabbits
• b. pneumonic tularemia: inhaled blood spray or other infectious aerosol (bio-weapon?): like pneumonic plague, high mortality
• c. ulcerative: cut or infected tick bite (most common) will lead to a local lesion that can spread to a regional lymph node and then a systemia
• Treatment: prompt, prolonged antibiotics: Russian-made vaccine

• a. 1st detected in the city of Lyme, Ct. in 1975 and thought to be arthritis
• b. Borrelia bergdorferi
• 1. spirochete
• 2. spiral shape
• 3. must be grown in animal host
• Outdoorsy people most likely to get Lyme disiease during spring and summer time

• 1. target-like rash at site fo tick-bite, which then fades (75% of patients have this)
• 2. 2-3 weeks after rash starts to fade, a systemia leads to flu like symptoms, irregular heart beat, neurological symptoms: facial paralysis, encephalitis (antibiotics effective up to this point)
• 3. moths to years later, symptoms caused by hypersensitivity to mo: severe arthritis
• Treatment: long term antibiotics

• Rickettsia spp.
• 1. very small Gm- rods
• 2. aerobes
• 3. obligate intracellular parasites
• Vectors: blood sucking insects like ticks, body lice, chiggers

• Spotted fever group is represented in the Western Hemisphere by Rocky Mtn spotted fever.
• 1. Rickettsia rickettsii
• 2. tick-borne
• Course of disease
• a. 2-14 days after tick bite: high fever, chills, headache
• b. 2-3 days later: petichial rash that spreads from extremities to thorax (not always present), mo lives in endothelial cells.
• c. late stage includes GI symptoms, encephalitis, renal failure, resp. failure, diffuse intravasc. coagulation and 20-40$ mortality.
• Avoidance/treatment:avoid being bitten by ticks, treat with antibiotics before late stage symptoms (difficult to Dx without the rash)

• Rickettsia prowazekii
• 1. endemic or louse-borne typhus
• 2. vector is body louse
• a. problem of crowded areas of poor personal hygiene, e.g. refugee camps, armies in the field
• 3. Siege of Granada in 1490, 5-6x due to disease
• 4. course of disease: abrupt high fever and stupor, headache, 40% of cases report rash, cardiac and CNS dysfunction with high mortality
• Avoidance/treatment: avoid being bitten by lice (field showers), vaccine is available, treat with antibiotics before late stage symptoms.
• (isolated cases difficult to Dx w/o the rash)
• In US, cases are mostly from fleas from flying squirrels

• 1. mo's: Clostridium perfringens and other Clostridial spp.
• a. Gm+, large sporing rods, anaerobic
• b. produces a wide variety fo vir and inv factors, esp. hydrolytic enzymes that enlarge the wound and spread the infection
• c. spores commonly found in soil and GI tract

• a. deep wound & introduction of feces or soil provides inoculum (e.g. military type wound)
• b. spores germinate in anaerobic environment
• c. cells produce copious amounts of hydrolytic enzymes: destroys circulation, tissue death, deepens the wound, spreads the infection.

• Swelling
• inflammation
• pain, fever
• foul-smelling gas in wound
• tissue necrosis
• then... systemia, with aggressive behavior, delirium and death

• a. prompt cleaning of wounds
• b. surgery to remove necrotic tissue (debridement)
• c. amputation
• d. hyperbaric chamber (kills Clostridia by forcing O₂ into the wound)
• Note: gangrene is a common consequence of diabetes, as progresive loss of circulation leads to tissue death in the toes, then legs.

• a. bacterial : anthrax
• b. viral: small pox, Burkett's Lymphoma and EB virus, mononuecleosis, CMV, hemorrhagic fevers
• c. protozoal: malaria, Chagas' disease, toxoplasmosis, Leishmaniasis
• d. helminthic: Schistosomiasis, swimmer's itch

• eating
• taste
• smell
• hearing
• air processing and conduction

• 1. mucous to entrap mo's
• 2. sneezing to dislodge
• 3. macrophages to engulf
• 4. IgA
• 5. normal flora
• 6. inflammation

• 1. Gm+ cocci in chains
• 2. facultative, but catalase - (acts like an aerotolerant anaerobe)
• 3. fastidious, nasopharyngeal species isolated on Blood agar
• 4. many species, classification based on surface Ag's

• 1. proposed by Rebecca Lancefield
• 2. different strep species were grouped by common surface Ag's
• 3. used agglutination tests,
• 4. groups are designated by letters

• Group A: Streptococcus pyogenes
• Group B: Strep agalactiae
• URT normal flora
• stubborn nosocomial systemia, pneumonia in comprimised
• serious systemia, meningitis acquired from mother during birth in neonates
• historically was a common cause of puerperal fever (childbirth fever) (Oliver Wendel Homes and I. Semmelweis and antisepsis)

• Group C: Streptococcus angiosus complex
• Stubborn opportunists
• Group D?: many spp.
• URT or GI normal flora
• Ocasional opportunists

• Variety of oral, GI and GU normal flora streptococci
• viridans = green, refers to appearance on blood agar
• occasional opportunists
• notables: S. mitis, S. salivarius, S. pnueumoniae
• lack surface Lancefield Ag's

• 1. are fastidious, usually grown on blood agar +/- increased CO₂ (differential medium)
• 2. Hemolysis of blood cells indicate which hemolysins the isolate makes:
• Group A: β-hemolysin, pathogen
• Group B: mostly β-hemolysin, likely pathogen
• Group C: mostly β-hemolysin, likely pathogen
• most others: α-hemolysin, non-pathogen or opportunist, except for S. pneumoniae

Group A, B and C: β-hemolysin, possible pathogen

• most other strepts: α- hemolysin, non-pathogen except for S. pneumoniae
• most other strepts: have α-hemolysin & are non-pathogenic (except for S. pneumoniae which has an obvious capsule)

• 1) β-hemolysin
• 2) Streptolysin: cytotoxic
• 3) M Ag (fimbrae): antiphagocytic
• 4) others

• 1) caused by Group A only
• 2) symptoms (throat epithelium, esp. tonsils) •swollen •+patches of pus on tonsils •red •pain •inflammation •fever, malaise
• 3) transmission: droplet nuclei, fomites
• 4) treatment: prompt antibiotics
• if strep throat goes untreated, 2° effects or infections can occur

• a) strain has a lysogenic phage that codes for an erythrogenic exotoxin
• b) rash of chest and extremities, later desquamation
• c) yellow exudate of tongue, later desquamation

• 2) otitis media (middle ear infection)
• 3) Rheumatic fever: cross reacting Ab’s attack mitral valve of heart and joints
• 4) Glomerulonephritis: inflammation of the kidneys with edema and hypertension
• c. other possible diseases of S. pyogenes: impetigo, necrotizing fasciitis, cellulitis, pyoderma, erysipelas, systemia, TSS, pneumonia

• 1) Corynebacterium diphtheriae
• a) Gm+ pleomorphic rod
• b) palisades arrangement
• c) + metachromatic granules (PHB)
• 2) course of the disease
• a) transmission: airborne, droplet nuclei, fomites
• b) sore throat, fever, malaise
• c) then diphtheritic membrane forms, a serum clot, which is Dx
• d) Toxin: phage-borne powerful exotoxin
• e) toxin leads to heart and kidney failure, trouble swallowing, death
• 3) treatment: DPT vaccine contains diph. toxoid
• a) very effective
• b) diph. well controlled in US
• 4) a cutaneous form exists, mostly in the homeless