Mizzou Medical Microbiology 3200 - Exam 4

characteristics of clostridium tetani

motile, gram + rod

where is clostridium tetani found

soil, dust, GI tract

fatality of clostridium tetani

18%, but 0% if vaccines are current

how does clostridium tetani infect

spore enters skin though membranes or puncture wound and germinates producing tetanus toxin.

what does tetanus toxin do

blocks the release of inhibitory neurotransmitter which results in muscle contraction with no relaxation

signs/symptoms of clostridium tetani

incubates few days-1 weeks

- tightening of neck and jaw

- perspiration, drooling, grouchiness, back spasm, irregular heartbeat

- patients dies because they cant exhale

treatment for clostridium tetani

penicillin/metronidazole

characteristics of clostridium botulinum

gram +, anaerobic bacteria

serotypes of clostridium botulinum

seven types affect different species

how infectious is clostridium botulinum and how does it work

only a few nanograms cause illness, it binds neuromuscular junctions and blocks the release of acetylcholine so there is no muscle contraction

what are the three forms of clostridium botulinum

food-borne, infant, wound

describe foodborne botulism and symptoms

-pre-formed toxins are ingested from contaminated food

- common from home canned food

- nausea, vomiting, diarrhea, double vision, difficulty speaking, descending weakness

describe infant botulism

spore ingestion, germination, toxin production

- insufficient competition from normal flora

- from honey, dust, corn syrup

- constipation, lack of expression, weak suckling, drooling, floppiness, poor head control, non-reactive pupils

describe wound botulism

- gets into would and develops anaerobically

- from ground in dirt or travel

- will not penetrate intact skin

- recently associated with black-tar heroin users

treatment of clostridium botulinum

repeated washing of GI tract, antibodies against toxin, NO antibiotics

what special thing is clostridium botulinum used for?

botox, keeps muscles from contraction

characteristics of clostridium difficile

gram + rod, motile via flagella

toxins of clostridium difficile

A & B toxins - cause water secretions and damage to mucosa, explosive diarrhea (self-limiting), life threatening pseudomembranous colitis

epidemiology of clostridium difficile

- leading cause of hospital acquired diarrhea

- opportunistic pathogen - antibiotic treatment suppresses normal flora

- number of cases increasing

- affects many elderly

- resistant to many antibiotics

pseudomembraneous colitis

life threatening, sections of colon wall become removed, perforation of colon, infection with fecal bateria

diagnosis of clostridium difficile

- patients undergoing antibiotic treatment

- culture - isolation from feces

- immunological detection of toxins

- just recovering organism from feces does not mean it caused it

treatment of clostridium difficile

stop antibiotics

- fecal transplant

- vancomycin/metronidazole/fidaxomicin(dificid)

characteristics of clostridia perfingens

gram + rod, anaerobic, non-motile

where is clostridia perfingens found

soil, water, sewage, GI tract of humans and animals

describe infection of clostridia perfingens

- 8-22 hrs after consumption, intense abdominal cramps and diarrhea

- usually over in 24 hrs

- disease from ingesting organism followed by growth and toxin release

toxins of clostridia perfingens

-alpha toxin= degrades cell membrane and kills WBCs

- perfringolysin O (PLO) - pore forming toxin

- enterotoxin - affects epithelial cells in GI tract

what does clostridia perfingens (food) result from

temperature abuse of food, spores survive cooking and food is improperly stored, meats, gravy

what are the diseases associated with clostridia perfingens

food poisoning and gas gangrene

describe food poisoning with clostridia perfingens

- intense abdominal cramps 8-22 hrs after consumption

- over within 24 hrs

- bacteria produce enterotoxins

complication of food poisoning with clostridia perfingens

very few deaths reported from dehydration or other complications

describe gas gangrene from clostridia perfingens

- non-invasive, but spores gain entry through wound and grow anaerobically

- alpha toxin and PLO induce swelling and tissue death

- foul smelling gaseous metabolic products

- shock, kidney failure, and death within 1 week

diagnosis for gas gangrene

lesions, presence of large gram + bacilli, naglar test

treatment of gas gangrene

remove dead tissues, large doses of anti-toxin, penicillin, apply oxygen

what is the mortality rate of gas gangrene

40%

what disease does treponema palindum cause

syphilis

epidemiology of treponema palindum (syphilis)

3rd most common bacterial STD in USA

- humans are only reservoirs

- 30% transmission rate from single sexual contact

- labile organism

describe the primary stage of syphilis

- lesion occurs 2-10 days post infection

- small-hard-painless chancre, ulcerated papule, very infectious

- regional swollen lymph node

- 3-8 wks chancre erodes and no further symptoms for 2-10 wks

describe the secondary stage of syphilis

- 2-12 wks after infection

- skin rash in90% of pts (macular, papular, pustular)

- mucus patches in patients mouth/throat

- fever, malaise, joint pain, hair loss, weight gain

-CNS involvement - headache, ocular disease

- lasts several weeks and subsides

- wart like lesions in moist sites

describe tertiary syphilis

- occurs in less than 1/2 untreated pts

- may begin 10-30 yrs after latent period

- inflammation due to pathogen components

- gummas (rubbery) of bones, organs, skin

- necrotic/perforated palate

- few lesions, not highly contagious

- CNS - dementia, ataxia, sensory defects

describe congenital syphilis

- mother to fetus transmission though placenta or birth canal

- pregnancies during primary and secondary stages result in still birth

- most common when pregnancies are in latent phase

- child has no symptoms at birth

- rash develops, multi-organ malformations, cardio problems

- bone destruction and mental problems

epidemiology of congenital syphilis

350-1000 cases per year

diagnosis of syphillis

- culture is not possible

- dark field microscopy of fresh skin lesion

treatment of syphillis

penicillins

tetracyclines if allergic

facts to know about leptospira

- acquired from rodent/animal urine contaminated water

- rowers and tri-athletes at risk

- flu like symptoms and failure of liver

what disease does borrelia burgodorferi cause

lyme disease

describe stage 1 of lyme disease

3-14 days after tick bite, bulls eye rash forms, fever, muscle pain, joint pain

- resolves in weeks

describe stage 2 of lyme disease

- weeks to months after infection

- disseminated infection - joint and muscle pain, multiple tissues and organs affected

- irregular heartbeat, facial paralysis, neurological conditions, conjuctivitis

describe stage 3 of lyme disease

may develop months or years after infection

- arthritis, immune disorders, high antibodies to borrelia

- disabling fatigue, memory loss, dementia, paralysis

what are the 3 spirochetes

leptospira

borrelia burgodorferi

treponema pallidum

diagnosis of borrelia burgodorferi

clinical signs - bull's eye rash

prevalence of ticks

culture from skin lesions

serological tests or PCR

treatment of borrelia burgodorferi - lyme disease

tetracycline, erythromycin = 10-3- days

- pts with arthritis = >1 month

epidemiology of borrelia burgodorferi

tick borne disease

- tick eggs not infected

- reservoir = deer and rodents

- takes ~6 hrs for bacteria to adapt to humans

- no human to human spread

- most common vector born disease in US

what disease is caused by bartonella henselae

cat scratch disease

characteristics of bartonella henselae

gram - bacilli

fastidious growth - needs enriched BAP, CO2, and time

facultative intracellular bacterium

transmission and epidemiology of bartonella henselae

cats and cat fleas

- 22,000 cases per year

-80-90% pts are

symptoms of bartonella henselae

papule/pustule

- regional adenopathy

- bacillary angiomatosis

- lesions in liver

- endocarditis

diagnosis of bartonella henselae

history of cat contact, positive skin test response, no evidence of other infection, histopathology of nodes

treatment of bartonella henselae

90% infection resolve on own

azithromycin

what disease does ehrlichia chaffeensis cause

ehrlichiosis - monocytic disease

characteristics of ehrlichia chaffeensis

obligate intracellular

gram - cocci

- grows in vacuole and replicated in phagosome in leukocyes

- cytoplasmic morulae

epidemiology of ehrlichia chaffeensis

-tick borne disease

- humans are dead end/accidental host

- reservoir= deer and ticks

- eggs are uninfected

- cases increasing

symptoms of ehrlichiosis

- may be asymptomatic

- clinical signs resemble RMSF = fever, headache, malaise, muscle ache

- rash develops in

diagnosis of ehrlichiosis

very difficult

- low WBC count

- immunoflurescence assay

- PCR

-isolation, which is difficult and time consuming

characteristics of rickettsia richettsiae

rod-shaped coccobacillus

gram -

obligate intracellular pathogen

no flagella based motility

free in cytosol

like endothelial cells and trick them into taking them up

what disease does rickettsia richettsiae cause

rocky mountain spotted tick fever

symptoms of rocky mountain spotted fever

5-10 days after bite = fever, chills, muscle pain, headache, nausea/vomiting, lack of appetite

2-5 days after fever = rash on extremities that spreads to trunk (35-60% pts)

pathenogenesis of rickettsia richettsiae

replication in endothelial cells

leakage of blood vessels

complications = GI tract probs, respiratory failure, hear probs

- 20% fatality if untreated

diagnosis of rickettsia richettsiae

culture is useless

look for antibodies via immunofluorescence

treatment of rocky mountain fever

tetracyclines (doxycycline)

chloramphenicol

epidemiology of rocky mountain spotted fever

vector= tick

reservoir - ticks, rodents, humans

no human to human

eggs of ticks are infected

what does chlamydophila psittaci cause

atypical pneumonia

characteristics of chlamydophila psittaci

zoonosis

gram - coccobacillus

epidemiology of chlamydophila psittaci

-seldom transmitted from human to human

-transmitted by contact/inhalation of infected bird droppings

-can be fatal in elderly if untreated

symptoms of chlamydophila psittaci

non-productive cough

10 incubation then sudden onset of headache and fever

what does chlamydophila pneumoniae cause

mild pneumonia

epidemiology of chlamydophila pneumoniae

humans are only known host

human to human transmission

symptoms of chlamydophila pneumoniae

may be asymptomatic or mild cough and malaise

correlation with atherosclerosis

what does mycoplasma pneumoniae cause

primary atypical pneumonia

mild upper respiratory disease 2-3 weeks after

characteristics of mycoplasma pneumoniae

- fried egg look

- extracellular pathogen- targets respiratory epithelial cells

-

symptoms of mycoplasma pneumoniae

non-productive cough

pathogenesis of mycoplasma pneumoniae

- adhere by specialized tip structure

-

diagnosis of mycoplasma pneumoniae

grows on serum containing media (slow)

cold-agglutination test

serological and DNA based tests

treatment of mycoplasma pneumoniae

ribosome inhibitors - tetracycline, erythromycin

penicillins DO not work

what does ureaplasma urealytieum cause

causes STD of human genital tract

- 80% individuals had >3 partnters

-50% non chlamydial, NGU in men and women

symptoms of ureaplasma urealytieum

inflammation of chorion and amnion, post partum fever, PID

characteristics of ureaplasma urealytieum

mycoplasma that produces urease > NH3 causes inflammation

chlamydia trachomatis causes

trachoma, inclusion conjunctivitis, non-gonococcal urethritis, lymphogranuloma venerum

different serotypes of chlamydia trachomatis

cause different disease

epidemiology of trachoma caused by chlamydia trachomatis

-leading cause of preventable blindness in the world

- limited to native americans in the US

transmission of trachoma caused by chlamydia trachomatis

typically eye to hand to eye, contaminated clothing, flies

- children are at greatest risk- largest reservoir

- overcrowding, poor hygiene, lack of water

describe trachoma symptoms

starts w/ tears, ocular discharge, inflammation of conjunctiva, follick formation, vasceularization of cornea, eyelid deformities (inversion)

- blindness results from long term scarring of cornea (10-20yrs)

epidemiology of inclusion conjunctivitis cause by chlamydia trachomatis

very common in infants - birth canal (44%)

- 17% adults get w/ genital tract infection

-50% conjunctivitis pts have genital tract infection

symptoms of inclusion conjunctivitis caused by chlamydia trachomatis

- mucopurulent yellow discharge

- inflammation of conjunctiva and swelling of eyelid

-heals spontaneously- rarely leads to scarring of cornea

epidemiology of non-gonococcal urethritis caused by chlamydia trachomatis

most common bacterial STD in the US

-10% of sexually active 15-35 yr olds infected

-1.6 million cases and increasing

-6x greater risk of cervical cancer

-3x greater risk of infection of HIV pts

symptoms of non-gonococcal urethritis caused by chlamydia trachomatis

-infection may be asymptomatic

- 40% untreated women will develop PID

-20% of those will be infertile

-18% will experience chronic pelvic pain

-9% will have life threatening tubal pregnancies

- manifests as genital discharge

describe lymphogranuloma venerum cause by chlamydia trachomatis

-more virulent & invasive STD

- most common in men

- enters via breaks in skin and primary lesion is ulcer

- 10-30 days= lymph buboes

~30% rupture if untreated, then obstruction

characteristics of candida albicans

dimporphic fungus that resides in GI tracts

- grown at

clinical presentation of candida albicans

mucocutaneous-skin & mucosal surfaces

- oral thrush, esophageal candidiasis, vulvovaginits, diaper rash

what is the treatment for candida albicans

topical antifungals and keeping skin dry

epidemiology of histoplasma capsulatum

arkansas, illinois, kentucky, missouri, ohio, tenessee