Bioscience Microbiology: Bacteriology II (Quiz 2)

human pathogens: gram positive cocci

streptococcus pyogenes

staphylococcus aureus

human pathogens: clostridium

tetanus, botulism, c. perfringens, c. difficile

human pathogens: bacillus

anthrax, b. cereus

human pathogens: STIs

gardnerella, chlamydia, neisseria, syphilis, chancroid

human pathogens: respiratory pathogens

diphtheria, h. influenzae, pertussis, legionella, strep. pneumoniae, pseudomonas

human pathogens: gastrointestinal pathogens

klebsiella, listeria, salmonella, shigella, cholera, h. pylori, campylobacter, e. coli

human pathogens: animal-mediated

yersinia pestis, pasteurella, bartonella

human pathogens: mycobacteria

TB, leprosy, atypical mycobacteria, mycoplasma

human pathogens: tick-borne pathogens

Lyme, Rocky Mountain spotted fever, anaplasma

streptococcus pyogenes

type

mode of transmission

vaccine

group A streptococcus

gram positive cocci chains

B-hemolytic: cause complete lysis of RBCs

modes of transmission: normal flora of human oropharynx and skin

no vaccine

streptococcus pyogenes virulence factors

pili: made M protein adhere to pharyngeal epithelium - antibodies against M protein cross-react with cardiac myosin

capsule: resists phagocytosis

glycocalyx: adheres strongly to endothelium of heart valves

enzymes that degrade human tissues

toxins

streptococcus pyogenes: virulence factors - toxins

exotoxin B: rapidly destroys tissue

hemolysins: streptolysin O and streptolysin A casue B-hemolysis and death of phagocytes

anti-streptolysin O

causes B-hemolysis and death of pathogens

indicator of prior infection

what does streptococcus pyogenes cause?

strep throat

acute rheumatic fever

necrotizing fasciitis

*most common cause of cellulitis

also causes impetigo, erysipelas, scarlet fever, streptococcal toxin shock syndrome

strep throat symptoms

severe exudative pharyngitis - yellow or white exudates on tonsils

fever

painful cervical lymphadenopathy

rheumatic fever symptoms

couple weeks after pharyngitis is untreated - reactive migratory polyarthritis with ref/hot/swollen joints, myocarditis and endocarditis damaging mitral and aortic valves, rash, fever, chorea

antibodies made to M protein cross-react with joints, heart, and brain tissues (arthritis, carditis, chorea)

immune complexes can deposit into glomeruli causing glomerulonephritis

necrotizing fasciitis

necrotizing fasciitis leading to tissue death

staphylococcus aureus

type

mode of transmission

vaccine

gram+ cocci clsuters

catalase positive, coagulase positive, B-hemolytic

part of normal flora in nose and some skin

- fomite sources, breast milk, vaginal flora

no vaccine

staphylococcus aureus: virulence factors

capsule: evades immune system

peptidoglycan: has endotoxin-like properties to cause septic shock - techie acid also induces septic shock

catalase: degrades H2O2 in phagolysosomes of phagocytes to survive

coagulase: causes plasmas to clot (prothrombin -> thrombin)

hemolysins: hemolyses RBCs to get iron for growth

staphylococcus aureus: virulence factors - toxins

enterotoxins: superantigen - cause prominent vomiting and watery diarrhea - resistant to heat, stomach acid and enzymes

toxic shock syndrome toxin: septic shock; up to 25% of strains have this

exfoliatin: protease that causes separation of epidermis - causes scaled skin syndrome and bullous impetigo

staphylococcus aureus: virulence factors - antibiotic resistance

B-lactamase: degrades B-lactam antibiotics (like penicillin) - 90% of S. aureus have this; encoded by plasmids

penicillin-binding protein mutations: resistant to B-lectamase resistant antibitoics such as methicillin and nagcillin - MRSA (most common cause of skin abscesses, like IVDU; cause pneumonia, necrotizing fasciitis, and sepsis in immunocompetent patients; 50% of hospital isolated strains)

vancomycin resistance cassette: encoded in transposons on plasmas - VRSA

staphylococcus aureus - skin infections

pyogenic infections - skin or soft tissue

scaled skin syndrome

toxic shock syndrome

erythematous, hot, painful, swollen skin - cellulitis firm to touch, abscesses can be squishy and exude purulence

can spread to surrounding structures and blood stream causing sepsis

tx: I&D, antibiotics, mupirocin ointment to reduce nasal colonization or chlorhexidine showers for nasal colonization

scaled skin syndrome (fever, large bull, erythematous macular rash that desquamates) - electrolyte imbalances can occur due to fluid losses; happens in young children

staphylococcus aureus - food poisoning

gastroenteritis

ingestion of preformed enterotoxin - short incubation period (1-8hrs)

staphylococcus aureus - toxic shock syndrom

fever, hypotension, diffuse sun-burn like rash that desquamates, multi-organ system involvement

clostridium tetani

type

mode of transmission

vaccine

anaerobic gram positive bacilli

spore forming

sił source of spores entering wound which enter skin - spores germinate in necrotic tissue with poor blood supply

vaccine for tetanus - need booster every 10 years

antitoxin available

clostridium tetani: virulence factors

tetanus toxin: blocks release of inhibitory neurotransmitters glycine and GABA

leads to excitatory neurons that are unopposed

toxin travels from wound to axons or via blood stream to spinal cord

clostridium tetani: response

muscle spasm and spastic paralysis

lock jack & neck muscles

grimace, opisthotonos, hyperreflexia

respiratory failure

clostridium botulinum:

type

mode of transmission

vaccine

anaerobic gram positive bacilli that forms spores

ingestion of improperly sterilized canned food in non-acid environment

can also get IVDU if spores are on skin

antitoxin, but no vax

bacteria in cans

spores on vegetables

bacteria can't grow in acidic environment - risk is in non-acidic cans

spores are heat resistant up to 115C, but toxin is heat labile

spores germinate in canned anaerobic environment - can swells from the gas production

clostridium botulinum: infants

honey with spores can germinate inside infant because it is favorable environment

lack of gastric acid - less normal flora, immature immune systems

spores can now germinate and toxin forms to cause illness similar to adults - no honey before 1 year old

clostridium botulinum: virulence factors

botulinum toxin acts as neuromuscular junction to block release of acetylcholine

toxin encoded on plasmids, in bacterial genome, or by bacteriophages

toxin goes from mucosa in GI tract to bloodstream and peripheral nerves

botulinum toxin

one of the most toxic compounds known

super Low LD50

clostridium botulinum leads to

descending weakness and flaccid paralysis - diplopia, dysphasia, ptosis, eventual respiratory muscle failure

infant clostridium botulinum leads to

hypotonia, weakness, respiratory problems

can recover spontaneously

wound clostridium botulinum leads to

spores contaminate in a wound, germinate and produce toxin at site

clostridium perfringens

type

mode of transmission

vaccine

anaerobic gram positive bacilli that form spores

normal flora of colon and vagina (non-spore vegetative form) - can enter skin via wounds or be ingested in contaminated food with heat-resistant spores located in soil

no vax

clostridium perfingens: virulence factors

alpha toxin: damages cell membranes leading to hemolysis and necrosis

degradative enzymes produce hydrogen gas in tissues - crepitus felt

enterotoxin: causes diarrhea

clostridium perfingens: gas gangrene

necrotizing fasciitis or myonecrosis

war wounds, automobile/motorcycle accidents, septic abortions (endometritis)

high mortality rate

I&D & antibiotics

clostridium perfingens: food poisoning

grow rapidly in reheated meat dishes

watery diarrhea, cramping, little vomiting

resolves in 24 hours

clostridium difficile:

type

mode of transmission

vaccine

anaerobic gram + bacilli - form spores

part of normal flora (3%) that can overgrow after antibiotic (like clindamycin) - also can be fecal-oral route

no vax

can do fecal transplants to outcompete with normal flora

clostridium difficile: virulence factors

exotoxin A: watery dirrhea

exotoxin B: causes apoptosis of mucosal cells; leads to pseudomembrane formation (thick, adherent, white/yellow plaques on mucosal surface of colon)

hypervirulent strain of clostridium difficile

more severe disease, more recurrences, and more resistant to metronidazole and fluoroquinolones

what does clostridium difficile cause?

pseudomembranous colitis: non-bloody diarrhea, fever, abdominal pain

many neutrophils in stool

toxic megacolon can occur

bacillus anthracis

type

mode of transmission

vaccine

gram + bacilli in chains that form spores

spores located in soil or found in animals - enter through breaks in skin or inhalation; ingesting contaminated meat; spores germinate once inside body

vaccine available and mAb protective antigen

bacillus anthracis: virulence factors

capsule resists phagocytosis

anthrax toxin with 3 components

anthrax toxin (bacillus anthracis): 3 components

protective antigen: makes pore in cell membranes to allow lethal factor and edema factor inside cell - antibodies against this

lethal factor: exotoxin protease causing necrosis

edema factor: exotoxin causing edema

bacillus anthracis causes

anthrax -

cutaneous: painless, necrotic lesions with significant edema - can progress to bacteremia and death

pulmonary: after inhalation, moves to mediastinal lymph nodes and causes hemorrhagic mediastinitis (wool-sorter's disease) - not transmissible; can case septic shock and death

GI: vomiting, bloody diarrhea, abdominal pain

bacillus cereus

type

mode of transmission

vaccine

gram+ bacilli; form spores

spores on grains (like rice) survive high heat and germinate when reheated or kept warm for long - ingested and infects GI tract

no vax

bacillus cereus: virulence factors & disease

enterotoxin causes water diarrhea

gastroenteritis - short incubation (4hrs) nausea and vomiting; long incubation (18hrs): watery diarrhea

gardnerella vaginalis

type

mode of transmission

vaccine

facultative gram+ bacilli

*cell wall thinner than typical gram+ so loses color and can appear pink

part of normal flora - dysbiosis where it can replace lactobacillus (pH over 4.5)

no vax

what does gardnerella vaginalis cause?

bacterial vaginosis - white/gray fishy discharge

most common vaginal infection in sexually active women

no inflammation, but can be itchy or irritating

clue cells - epithelial cells covered with bacteria

higher incidence of pre-term deliveries

chlamydia trachomatis

type & info

obligate intracellular bacteria with cell walls that resemble gram negatives

extracellular, metabolically inert "sporelike" elementary body which reorganizes into larger metabolically active reticulate body which forms daughter cells by binary fission then turn back into elementary bodies that are released from the cell

inclusion body - site of replication inside cell - seen in giemsa stains

chlamydia trachomatis

mode of transmission

vaccine

direct sexual contact or through birth canal - enter GU tract, conjunctiva, respiratory tract

infects epithelial cells of mucous membranes or lungs

usually co-infection with N. gonorrhea

vaccine in clinical trials

chlamydia trachoma's: presentation

asymptomatic often

urethritis

cervicitis

lymphogranuloma venereum (genital lesions and lymphadenopathy)

pneumonia

conjunctivitis

reiter's syndrome

chlamydia urethritis

clear, mucoid urethral discharge in males --> epididymitis, prostatitis, or proctitis

chlamydia cervicitis

purulent vaginal discharge and intermenstrual bleeding in females --> PID with severe suprapubic pain from fallopian tube infection; sterility or ectopic pregnancy from tube scarring

chlamydia conjunctivitis

non-purulent discharge - can lead to blindness; can infect neonates while passing through birth canal

chlamydia reiter's syndrome

uveitis, urethritis, arthritis

from antibodies cross-reacting with antigens of cells in those areas

(can't see, can't pee, can't climb a tree)

neisseria gonorrhoeae

type

transmission

vaccine

gram - diplococci - pairs that look like kidney beans

direct contact (sexual or passage through birth canal) - infect GU or GI tract

no vax

neisseria gonorrhoeae virulence factors

pili - attach to urinary tract epithelium, resist phagocytosis

lipooligosacharide endotoxin

IgA protease - degrades IgA antibodies allowing bacteria to adhere to mucous membranes

penicillinase: degrades penicillin

neisseria gonorrhoeae presentation

urethritis/epididymitis

cervicitis

conjunctivitis (white purulent discharge; passed to neonate)

anorectal infection (blood or purulent discharge)

pharyngitis

disseminated infections in immunocompromised individuals (bacteremia) that manifest as arthritis, tenosynovitis or pustules in skin

neisseria gonorrhoeae: urethritis or epididymitis

purulent urethral discharge and dysuria in males

neisseria gonorrhoeae: cervicitis

purulent vaginal discharge and intermenstrual bleeding in females

PID which can lead to sterility or ectopic pregnancy from scarring in tubes

neisseria meningitides

type

transmission

vaccine

gram negative diplococci (pairs)

airborne droplets - can be asymptomatic carrier (5%); enters nasopharynx and spread to bloodstream - disseminates to meninges and joints

vaccine available

Neisseria meningitidis; virulent factors

polysaccharide capsule: resists phagocytosis

lipooligosaccharide endotoxin - cause fever and shock

IgA protease

factor H binding protein - inhibits complement

antibiotic resistance - PCN, sulfonamides, ciprofloxacin

neisseria meningitidis casues

epidemic meningitis and meningococcemia (high fever, hypotension and petechiae/purpura) can lead to DIC and adrenal insufficiency

treponema pallidum

type

transmission

vax

virulence factors

motile spirochetes; grow slowly

direct contact with skin or mucous membranes

cross placenta to infect fetus (vertical transmission)

rarely bloodborne

no vax

antibiotic resistance: azithromycin

treponema pallidum can cause

primary, secondary, tertiary syphilis

congenital syphilis

can be latent for years

treponema pallidum: primary syphilis

contender ulcers (chancres) then spread to bloodstream

treponema pallidum: secondary syphilis

maculopapular rash on plasma and soles (moist papules on skin and mucous membranes; condylomata late on genitals)

treponema pallidum: tertiary syphilis

granulomas (gummas) of skin and bones

neurosyphilis in CNS or PNS demyelination general paresis - paralysis and dementia

tabes dorsalis - loss of coordination

cardiovascular lesions - aortitis or ascending aortic aneurysm

treponema pallidum - congenital syphilis

via placenta

skin/bone lesions - hutchinson's teeth, mulberry molars, saber shins, saddle nose, rhagedes (fissures at angle of mouth/nose) and frontal bossing

can cause hepatosplenomegaly, interstitial keratitis, snuffles, deafness, stillbirth

haemophilus ducreyi

type

transmission

vax

virulence factors

gram negative bacillus; tropical countries

sexually transmitted

no vax

penicillinase: degrades PCN

what does haemophilus ducreyi cause?

chancroid - painful penile lesions, non-indurated ulcers, local lymphadenitis

Corynebacterium diphtheriae

type

transmission

vaccine

gram + bacilli

airborne droplets - infect upper respiratory tract; infect broken skin

toxoid vaccine

antitoxins

(balto, togo)

boosters every 10 years

Corynebacterium diphtheriae: virulence factors

diphtheria toxin carried by bacteriophage - cause cell death and pseudomembrane formation in pharynx and heart - thick, adherent, gray/yellow exudates on mucosal surface of throat

what does corynebacterium diphtheriae cause?

diphtheria - thick grayish pseudomembrane on tonsils and throat, fever, pharyngitis, cervical lymphadenopathy

pseudomembrane can extend to larynx and trachea - obstruct airway

myocarditis and endocarditis with arrhythmias and circulatory collapse

nerve palsies and paralysis of cranial nerves and peripheral neuritis of extremities

haemophilus influenzae

type

transmission

vax

gram - bacilli

airborne droplets - asymptomatic; infects upper and lower respiratory tract; spread via blood stream to meninges

vax available

haemophilus influenzae

virulence

polysaccharide capsule - resists phagocytosis

IgA protease

LPS endotoxin

haemophilus influenzae causes

URIs

meningitis

sepsis in young children - most common cause of epiglottitis

pneumonia in adults with COPD

bordetella pertussis

type

transmission

vax

gram - coccobacilli

airborne droplets infect upper respiratory tract

vax available

bordetella pertussis: virulence factors

capsule

pili

pertussis toxin (cause edema in mucosa leading to severe cough)

tracheal cytotoxin (part of peptidoglycan that damages ciliated cells in respiratory tract - LPS endotoxin works along with this to kill cells)

bordetella pertussis causes

whooping cough - acute tracheobronchitis - mild URI symptoms then severe paroxysmal cough (1-4 weeks "100 day cough")

productive cough followed by whoop

sometimes post-tussive emesis

whoop caused by swollen epiglottis - heard more in children

can progress to pneumonia and death

legionella pneumophila

type

transmission

vaccine

gram negative bacilli with flagella (motile) - replicate inside amebae (ensure survival)

inhalation of aerosolized contaminated environmental water sources - air conditioners, water-cooling towers & hot tubs

no vaccine

legionella pneumophila

virulence factors

LPS endotoxin

catalase (resist destruction in phagolysosomes

biofilm formation

beta-lactamase (degrades PCNs)

what does legionella pneumophila cause?

Legionnaire's disease: atypical pneumonia with confusion, diarrhea and acute kidney injury

can lead to sepsis and Pontiac fever

what kills legionella pneumophila?

hyperchlorination and high temperatures

streptococcus pneumoniae

type

transmission

vaccine

gram + diplococci or short chains

alpha-hemolytic: incomplete RBC lysis

normal flora of oropharynx that cause problems when entering respiratory tract

vaccine available - provider at least 5 years immunity

streptococcus pneumoniae: virulence factors

capsule: evade phagocytosis

lipoteichoic acid (LTA): causes septic shock

IgA protease

pneumolysin: causes alpha-hemolysis (partial lysis of RBCs)

penicillin-binding protein mutations: resistance

streptococcus pneumoniae - pneumonia

invades alveoli causing outpouring of fluid, RBCs, WBCs

fever, cough, red/rusty brown sputum, pleuritic pain

*most common cause of community acquired pneumonia

streptococcus pneumoniae causes

pneumonia, otitis media, sinusitis, mastoiditis, meningitis

*most common cause of bacteria in asplenic patients

pseudomonas aeruginosa:

type, characteristics

transmission

vaccine

gram negative bacilli

blue-green pigmented

fruity odor

opportunistic pathogen

mainly in soil and water, but can be part of intestinal flora (10%) - contamination of respiratory therapy and anesthesia equipment, IV fluids, distilled water, tap water

no vax

pseudomonas aeruginosa: virulence factors

glycol biofilm formation - especially in CF and burn patients

LPS endotoxin

Type 3 secretion system (injectosomes) - injects exotoxins directly into cell which avoids antibody response (exotoxin A - causes tissue necrosis like diphtheria toxin)

elastase and proteases - enzymes that facility invasion of organisms into blood stream

abx and disinfectant resistance

pseudomonas aeruginosa causes

disease in immunocompromised patients (opportunistic pathogen) - sepsis, pneumonia (CF), chronic wounds, UTIs, malignant, omits external (DM patients)

sepsis -> spreading of bacteria out to skin causing black necrotic lesions (ecthyma gangrenosum)

folliculitis - swimming pool/hot tub

corneal infection - contact lens

osteochondritis of foot - puncture wounds through shows

klebsiella pneumoniae

type

transmission

vax

facultative anaerobic gram - bacilli

nitrate reduces - nitrate

part of normal colon flora (also in soil and water; normal in some respiratory tracts)

no vax

klebsiella pneumoniae virulence factors

LPS endotoxin

capsule

extended-spectrum B-lactamases (ESBLs): resistant to almost all antibiotics

usually opportunistic causing UTIs and pneumonia - spread to bloodstream, meninges, and liver

pneumonia with thick, mucoid bloody sputum and currant jelly - can lead to abscesses and necrosis

listeria monocytogenes

type

transmission

vax

gram+ bacilli motile and live intracellularly

ingestion of contaminated food - unpasteurized milk, raw veg, undercooked or deli meat

worldwide in animals, plants and soil

goes from GI tract to vaginal - can be transmitted via placenta or during delivery

no vax

listeria monocytogenes virulence factors

beta hemolysis

cold enhancement (grows well in cold temp)

internalin: allows for invasion of deeper tissues

listeriolysin: evades phagosomes

actin rockets: propel bacteria form one cell into membrane of another cell

listeria monocytogenes causes

meningitis and sepsis in newborns, pregnant women and immunosuppressed

can lead to premature delivery and spontaneous abortion in infected in utero

meningitis develops 1-4 weeks post-partum in infected during delivery

also febrile gastroenteritis (vomiting, watery diarrhea, cramping)

salmonella typhi and enterica

type, characteristics

transmission

vaccine

flagellated, facultative anaerobic gram- bacilli

produces nitrites and hydrogen sulfide

fecal-oral route, ingestion of contaminated drinking water or food (poultry, eggs, dogs, reptiles are reservoirs for s. enterica)

humans only reservoir for s. typhi (some individuals are asymptomatic carriers - in gallbladder and excreted in feces) - Typhoid Mary

vaccine for s. typhi (50-80% protection)