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Musculoskeletal
Microbiology
138
Medical
Graduate
05/29/2011

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Cards

Term
Pyogenic Osteomyelitis reach bone by...
Definition
hematogenous spread, extension from a contiguous site, direct implantation
Term
Osteomyelitis spread in children
Definition
Hematogenous in origin, develops in long bones, injury to mucosa, minor infection of skin
Term
Osteomyelitis spread in adults
Definition
Complication of open fractures, surgical procedures, diabetic infections of foot
Term
Most common organism in pyogenic osteomyelitis
Definition
Staph. aureus, organisms express receptors for bone matrix components such as collagen
Term
Pyogenic osteomyelitis organisms from individuals with genitourinary tract infections or IV drug users
Definition
E. Coli, Pseudomonas, Klebsiella
Term
Neonatal pyogenic osteomyelitis
Definition
H. influenzae, group B steptococci
Term
Pyogenic osteomyelitis organism for those w/sickle cell
Definition
Salmonella
Term

Areas of bone infected in:

1. neonates

2. children

3. adults

Definition

1. metaphysis, epiphysis or both

2. metaphysis, long bones w/vascularity

3. metaphysis, epiphysis, subchondral regions, vertebral

Term
Time period for which bone undergoes necrosis in pyogenic osteomyelitis
Definition
w/in 48 hrs.
Term
What is the dead piece of bone in osteomyelitis called?
Definition
Sequestrum
Term
Consequences of epiphyseal infection in infants
Definition
Infection spreads through the articular surface or along capsular and tendoligamentous insertions into a joint, producing septic arthritis, also happens in vertebrae
Term
Symptoms after first week of osteomyelitis infection
Definition
Osteoclastic bone resorption, deposition of reactive bone
Term
Name of sleeve of living tissue around segment of devitalized infected bone
Definition
Involucrum
Term
Morphologic variants of osteomyelitis
Definition
Brodie abcess (sequestered focus of staph osteomyelitis in long bone of adults), sclerosing osteomyelitis of Garre
Term
Osteomyelitis radiologic findings
Definition
Lytic focus of bone destruction surrounded by a zone of sclerosis
Term
Tuberculous Osteomyelitis Spread
Definition
Usually blood borne and originate from a focus of active visceral disease during intial stages of primary infections, may also occur from direct extension or draining lymphatics
Term

Most common sites tuberculous osteomyelitis

irreversible inhibitor of COX-1 and COX-2

  covalent modification of enzyme (acetylation of ser residue)

 

  toxicity:

  ti

Definition
 Spine (Pott disease), then knees and hips
Term
tuberculous osteomyelitis symptoms
Definition
pain on motion, tenderness, low-grade fevers, chills, weight loss, arthritis, sinus tract formation, psoas abscess, amyloidosis
Term
Where do spirochetes localize in congenital skeletal syphilis?
Definition
areas of active endochondral ossification and in the periosteum
Term
Most frequently involved bones in skeletal syphilis
Definition
nose, palate, skill, extremities
Term
Massive reactive periosteal bone deposition on medial and anterior surfaces of tibia in syphilis is called what?
Definition
saber shin
Term
Form of reactive arthritis defined by traid of arthritis, nongonococcal urethritis or cervicitis, and conjunctivitis
Definition
Reiter Syndrome
Term
Reiter Syndrome caused by autoimmune rxn initiated by prior infection of what?
Definition
GI tract and genitourinary system
Term
Enteritis-Associated Arthritis caused by what? What specifically on these organisms?
Definition

GI infection by Yersinia, Salmonella, Shigella, Campylobacter

Outer cell membranes w/LPS

Term
Chronic inflammatory arthropathy that affects peipheral and axial joints and entheses
Definition
Psoriatic Arthritis, like rheumatoid arthritis, but not as severe
Term
Lyme arthritis is caused by what organism
Definition
Borrelia burgdorferi
Term
Onset of lyme arthritis
Definition
late, involves large joints
Term
Most common organism of arthritis in sexually active people
Definition
Neisseria gonorrhea
Term
Borrelia are what type of bacteria?
Definition
weakly staining, gram-negative spirochetes
Term
Borrelia nutritional needs? movement?
Definition
microaerophilic, periplasmic flagella responsible for twisting motility
Term
Outer surface protein functions in Borrelia
Definition
OspA expressed in midgut of unfed ticks and binds gut proteins, repressed during feeding and OspC expressed to move to salivary glands and into mammals
Term
What is the leading vector-borne disease in the US?
Definition
Lyme disease
Term
Where is the three principal foci of infection in the US?
Definition
Northeast, Mid-Atlantic States, Pacific West
Term
What are the major vectors of Lyme disease?
Definition
Hard ticks, Ixodes scapularis in NE, mid-Atlanta, and Midwest and Ixodes pacificus on west Coast
Term
What are the major hosts of Lyme disease in US? 
Definition

White-footed mouse- larval and nymph forms of Ixodes

White-tailed deer- adult Ixodes

Term
When can humans be infected and in what lifestage of the organism?
Definition
Second blood meal in spring by nymph and third blood meal in late summer by adults
Term
What is the lesion called that develops from the site of a tick bite?
Definition
Erythema migrans, not pathognomonic
Term
Early signs of Lyme disease
Definition
malaise, severe fatigue, headache, fever chills, musculoskeltal pains, myalgias, lymphadenopathy for an avg. of 4 weeks
Term
Clinial Case Definition of Lyme Disease
Definition

Either of the following:

Erythema migrans

At least one late manifestation (musculoskeletal, nervous, cardiovascular involvement) and laboratory confirmation of infection

Term
Laboratory Criteria for Diagnosis
Definition

At least one of the following:

Isolation of Borrelia burgdorferi

Demonstration of diagnostic levels of IgM or IgG antibodies to the spirochetes

Significant increase in antiboy titer between acture and convalescent serum samples

Term
Is B. burgdorferi seen in clinical specimens?
Definition
rarely
Term
What is the diagnostic test of choice for Lyme disease?
Definition
serologic testing, specifically IFA and EIA, tests for later stages
Term
Early manifestations of Lyme disease treated with what?
Definition
amoxicillin, doxycycline, cefuroxime
Term
Recurrent arthritis from Lyme disease or central or peripheral nervous system treated with what?
Definition
ceftriaxone, cefotaxime, penicillin G
Term
How should those with chronic symptoms of Lyme disease be treated?
Definition
symptomatically, no more antibiotics
Term
What type of bacteria are Clostridium?
Definition
gram-positive
Term
What is the structure of C. tetani?
Definition
large, motile, spore-forming rod that produces round, terminal spores like a delicious drumstick
Term
Why is C. tetani difficult to grow?
Definition
Because of oxygen toxicity
Term
What are the two types of C. tetani toxins?
Definition

Tetanolysin- an oxygen-labile hemolysin

Tetanospasmin- a plasmid-encoded, heat labile neurotoxin, nonconjugative

Term
Which C. tetani toxin is responsible for clinical manifestations of tetanus and how?
Definition
Tetanospasmin (A-B toxin), produced during stationary phase of growth, released when cell is lysed, carbohydrate-binding domain of heavy chain, carboxyl-terminal portion, binds to specific sialic acid receptors and adjacent glycoproteins on presynaptic membrane of motor neurons
Term
How does tetanospasmin travel once attached to motor neurons?
Definition
internalized in endosomal vesicles and transported in neuron axon to motor neuron soma in spinal cord by retrograde axonal transport, endosome becomes acidified, conformational change in N-terminus, followed by insertion into endosome membrane and passage of toxin light chain into cytosol of cell
Term
How does tetanospasmin work?
Definition
Light chain is a zinc endopeptinase that inactivates proteins like synaptobrevin that regulate release of inhibitory neurotransmitters which leads to unregulated excitation and spastic paralysis, irreversible
Term
Where is C. tetani found?
Definition
fertile soil and in GI tracts of many animals
Term
How does C. tetani survive even though it is extremely susceptible to oxygen toxicity?
Definition
spores, also aided by necrotic tissue, calcium salts, pyogenic infections
Term
How is the duration of the incubation period of C. tetani determined?
Definition
Distance of primary wound to CNS
Term
What is presenting sign generalized tetanus in most C. tetani patients?
Definition
involvement of masseter muscles (trismus and lockjaw), sardonic smile (risus sardonicus), drooling, sweating, irritability, back spasms
Term
How is C. tetani diagnosed?
Definition
clinical presentation
Term
What is the structure and physiology of C. botulinum?
Definition
large, heterogenous, fastidious, spore-forming, anaerobic
Term
Human disease is associated w/what types of C. botulinum?
Definition
A, B, E, F
Term
What are the characteristics of C. botulinum toxin?
Definition

Has zinc-endopeptidase activity and a large, nontoxic subunit

Complexed w/nontoxic proteins that protect the neurotoxin during passage through the digestive tract

Term
How does the C. botulinum toxin get into cells and cause harm?
Definition
From gut, carboxyl-terminal portion of heavy chain binds to sialic acid receptors and glycoproteins on presynaptic membrane of motor neuron of peripheral and cranial nerves, endocytosis, remains at neuromuscular junction, release of light chain, inactivates SNARE proteins (synaptobrevin, SNAP 25, syntaxin) that regulate ACh, leading to flaccid paralysis
Term
Where is C. botulinum found?
Definition

soil and water

Type A- neutral or alkaline soil west of Mississippi

Type B- easter part of country in rich, organic soil

E- wet soil

 

Term
What are the 4 types of botulism found in US?
Definition

1. classic of foodborne- consumption of home-canned foods (A and B) and preserved fish (E)

2. infant botulism- consumption of foods w/spores, honey, milk powder, soil

3. wound botulism

4. inhalation botulism- major concern for bioterrorism

Term
What are the initial signs of foodborne botulism?
Definition
blurred vision w/fixed, dilated pupils, dry mouth, constipation, and abdominal pain
Term
What are the progressive signs of foodborne botulism?
Definition
Bilateral descending weakness of peripheral muscles, respiratory paralysis
Term
How do patients recover from C. tetani and C. botulinum?
Definition
wait for affected nerve endings to regrow
Term
What is the most common form of botulism in US?
Definition
infant botulism
Term
Where does C. botulinum become established in infants?
Definition
GI tract
Term
How can you isolate the C. botulinum specimen?
Definition
heat specimen for 10 min. at 80 degrees to kill all nonclostridial cells
Term
What are the treatment measures for botulism?
Definition

1. adequate ventilatory support

2. elimination of organism from GI tract through gastric lavage and metronidazole or penicillin

3. use of trivalent botulinum antitoxin

Term
Lymphocutaneous Sporotrichosis is cause by what organism?
Definition
Sporothrix schenkii
Term
True or False: S. schenckii is thermally dimorphic.
Definition
True
Term
Where is sporotrichosis normally found?
Definition

warmer climates, Japan, Mexico, Brazil, Uruguay, Peru, Clumbia

outbreaks related to forest work, mining, and gardening

zoonotic transmission through armadillo hunters and infected cats

Term
When does lymphangitic sporotrichosis classically appear?
Definition
following local trauma to an extremity
Term
What are the symptoms of sporotrichosis?
Definition
primary skin lesions in a linear chain along lymphatic drainage
Term
In what conditions does the S. schenckii grow as a mold? yeast?
Definition

room temp, body temp (pleomorphic)

Appearance of Splendore-Hoeppli material surrounding yeast cells

Term
What is the treatment for lymphocutaneous sporotrichosis?
Definition

oral potassium iodide in saturated solution which has frequent adverse side effects

itraconazole also effective

fluconazole last resort

Term
What are the characteristics of Chromoblastomycosis?
Definition
chronic fungal infection affecting skin and subcutaneous tissues, characterized by development of slow-growing verrucous nodules or plaques
Term
Where is Chromoblastomycosis normally seen?
Definition
in tropics, where warm, moist environment coupled w/lack of footwear or clothing predisposes individuals to direct inoculation w/infected soil or organic matter
Term
What organisms are associated w/Chromoblastomycosis?
Definition
Fonsecaea, Cladosporium, Exophiala, Cladophialophora, Rhinocladiella, Phialophora
Term
What is the common characteristic of all fungi that cause Chromoblastomycosis in tissue?
Definition
All form muriform cells that are chestnut brown due to melanin in their cell walls, these cells divide by internal septation and appear as cells with vertical and horizontal lines
Term
What is the most common cause of Chromoblastomycosis in US?
Definition
Fonsecaea pedrosoi, most often involves lower extremities
Term
What are the clinical syndromes of Chromoblastomycosis?
Definition

chronic, pruritic, progressive, indolent, and resistant to treatment

Early lesions are small, warty papules and enlarge as multiple, large, cauliflower-like growths

Large lesions are hyperkeratotic

Term
What prep helps identify causative agent of Chromoblastomycosis in scrapings of warty lesions?
Definition
KOH
Term
What are the most effective drugs for Chromoblastomycosis?
Definition

Itraconazole and terbinafine, posaconazole more recently

Squamous cell carcinomas may develop

Term
What is eumycotic mycetoma characterized by?
Definition
formation of multiple granulomas and abscesses that contain large aggregates of fungal hyphae known as granules or grains, drain through skin
Term
What are the etiologic agents for eumycotic mycetoma?
Definition
Phaeoacremonium, Curvularia, Fusarium, Madurella, Exophiala, Pyrenochaeta, Leptosphaeria, Scedosporium
Term
What are the granules of eumycotic mycetoma like?
Definition

composed of septate fungal hyphae, frequently distorted and bizarre, large, spherical, thick-walled chlamydoconidia often present

Splendore-Hoepplie material often interdigitates

Term
Where is eumycotic mycetoma typically seen?
Definition
tropical areas w/low rainfall, more frequent in Africa and Indian subcontinent, also Brazil, Venezuela, Middle East
Term
How are patient infected with eumycotic mycetoma?
Definition
traumatic percutaneous implantation of etiologic agent into exposed parts of body, men more than women
Term
What are the clinical symptoms of eumycotic mycetoma?
Definition
Initially small nodule, then sinus tracts on skin and drain serosanguineous fluid that contains granules
Term
What is the treatment for eumycotic mycetoma?
Definition
hard to treat, usually unsuccessful
Term
What is subcutaneous zygomycosis caused by?
Definition
Zygomycetes of the order Entomophthorales: Conidiobolus coronatus and Basidiobolus ranarum
Term
How does the fungi cause a chronic subcutaneous form of zygomycosis?
Definition
Sporadically as a result of traumatic implantation of the fungus present in plant debris in tropical environments
Term
Where does B. ranarum cause infection?
Definition
Subcutaneous infection of proximal limbs in children
Term
Where does C. coronatus cause infection?
Definition
Localized to the facial area, primarily in adults
Term
What type of fungi are B. ranarum and C. coronatus?
Definition
saprophytes
Term
How are B. ranarum and C. coronatus spread?
Definition

B. ranarum- through traumatic implantation of the fungus into subcutaneous tissues of thighs, buttocks, and trunk

C. coronatus- through inhalation of fungal spores, which invades the tissues of the nasal cavity, paranasal sinuses, facial soft tissues

10:1 male to female ratio

Term
What is the clinical syndrome of B. ranarum?
Definition
Disk-shaped rubbery masses that may be large and localized to shoulder, pelvis, hips, thighs
Term
What is the clinical syndrome of C. coronatus?
Definition
Infection confined to rhinofacial area
Term
What is the treatment for subcutaneous zygomycosis infection?
Definition

itraconazole

Oral potassium iodide has been used

Term
What is subcutaneous phaeohyphomycosis caused by?
Definition
A heterogenous array of fungal infections caused by pigmented, dematiaceous fungi present as irregular hyphae
Term
What is the morphology of the agents that cause phaeohyphomycosis?
Definition

All grow as black molds in culture and appear as dark-walled, irregular, hyphal and yeastlike forms in tissue

May require Fontana-Masson melanin stain to confirm

 

Term
What are the most frequent agents of phaeohyphomycosis?
Definition
Exophiala jeanselmei, Alternaria, Curvularia, Phaeoacremonium, Bipolaris
Term
Route of infection of phaeohyphomycosis
Definition
Implantation
Term
How does phaeohyphomycosis most commonly present?
Definition
Solitary inflammatory cyst, generally on feet and legs, can also cause brain cysts
Term
What is the main treatment for phaeohyphomycosis?
Definition
Surgical excision, also can use itraconazole with or w/o concomitant flucytosine
Term
What is Lacaziosis caused by?
Definition
Lacazia loboi, in the order Onygenales and family Ajellomycetaceae
Term
What is the morphology of Lacazia loboi?
Definition
double-refractile cell wall, reproduces by budding, some may have one or two secondary buds
Term
Where is Lacazia loboi endemic?
Definition
tropical regions of Central and South America, saprophyte of soil in thick vegetation such as the Amazon rain forest
Term
What mammal besides humans can carry Lacazia loboi?
Definition
dolphins
Term
What are the clinical symptoms of Lacazia loboi?
Definition
Polymorphic dermal lesions, most common are nodular keloid-like lesions, long dormancy period
Term
What intensely stains Lacazia loboi?
Definition
GMS and PAS
Term
What is the treatment for Lacazia loboi?
Definition
surgical excision
Term
What is the main organism that causes trichinosis?
Definition
T. spiralis
Term
Where does the adult form of T. spiralis live?
Definition
Duodenal and jejunal mucosa of flesh-eating mammals, infections form is present in striated muscles of carnivorous and omnivorous mammals
Term
What is the life cycle of T. spiralis?
Definition

1. Infection begins when meat contains encysted larvae is digested

2. Larvae leaves meat in small intestine and w/in 2 days develop into adult worms

3. Single fertilized female produces more than 1500 larvae in 1-3 months

4. Larvae move from the intestinal mucosa into the bloodstream and are carried in the circulation to various muscle sites throughout the body, where they coil in striated muscle fibers and become encysted

5. Larvae remain viable for many years and are infectious if ingested by a new animal host

Term
What muscles are most frequently involved w/T. spiralis?
Definition
extraocular muscles of the eye, the tongue, the deltoid, pectoral, intercostal muscles, the diaphragm, gastrocnemius
Term

What animals have the greatest prevalence of T. spiralis?

 

Definition
Pigs, also polar bears and walruses
Term
At what point do you see symptoms from invasion of T. spiralis?
Definition

when 100 present, significant disease

1000 to 5000 is very serious, sometimes death

Term
What are the signs and symptoms of T. spiralis?
Definition

few larvae, mild flu-like syndrome

more extensive, persistent fever, GI distress, eosinophilia, muscle pain, periorbital edema

Splinter hemorrhages beneath nails cause by vasculitis from toxic secretions

Severe infecton and death results from myocarditis, encephalitis, pneumonitis, respiratory arrest

As larvae encyst in muscle, edema and inflammation occurs, calcification in 5-6 months

Term
What is the treatment for T. spiralis?
Definition

Primarily symptomatic

Mebendazole may halt production of new larvae

Steroids recommended for severe symptoms

Term
What are the organisms that cause Bancroft and Malayan filariasis respectively?
Definition
W. bancrofti and B. malayi
Term
What are the vectors of Bancroft and Malayan filariasis?
Definition
Anopheles, Aedes, and Culex mosquitoes
Term
What is the life cycle of W. bancrofti and B. malayi?
Definition

1. Larvae migrate from the location of bite to lymphatic system, primarily in arms, legs or groin, where growth adulthood occurs

2. 3 to 12 months after initial infection, adult male worm fertilizes the female, which produces sheathed larval microfilariae that find way into circulation

3. Microfilariae in blood is diagnostic for human disease and is infective for feeding mosquitoes

4. In mosquito, larvae moves through stomach and thoracic muscles in developmental stages and migrate to proboscis

5. In proboscis, become infective, third-stage larvae and transmitted by feeding mosquito

Adult form in humans can persist for 10 years

Term
Where does infection with W. bancrofti occur?
Definition

tropical and subtropical areas and is endemic in central Africa, along Mediterranean coast, in many parts of Asia

No animal reservoir has been identified

Term
Where does infection with B. malayi occur?
Definition

Malaysia, India, Thailand, Vietnam and parts of Asia

Animal reservoirs are cats and monkeys

Term
What are the clinical signs of W. bancrofti and B. malayi?
Definition

acute presentation arises from inflammatory response to presence of molting adolescent worms and dead or dying adults w/in lymphatic vessels, lymph nodes enlarge involving extremities, scrotum, testes

this may also lead to filarial elephantiasis

Term
What are some laboratory diagnoses of W. bancrofti and B. malayi?
Definition
Microfilariae in Giemsa-stained blood, buffy coat films, membrane-filtration technique w/saline, both have nocturnal and subperiodic periodicity which results in greater numbers at night, sheath
Term
What is the treatment of W. bancrofti and B. malayi?
Definition
Drug of choice is diethylcarbamazine, surgical therapy for lymphatic obstruction
Term
What is the life cycle of Onchocerca volvulus?
Definition

1. Infection occurs w/introduction of larvae through the skin during biting and feeding of the Simulium or blackfly vector

2. Larval worms migrate from skin to subcutaneous tissue and develop into adult male and female worms

3. Adults become encased in fibrous subcutaneous nodules w/in which they remain viable for as long as 15 yrs

4. Female worm, after fertilization by male, begins producing as many as 2000 nonsheathed microfilariae each day

4. Microfilariae exit capsule and migrate to skin, eyes, and other body tissues, are infective for feeding blackflies

Term
Where is Onchocerciasis and O. volvulus endemic?
Definition
Africa, especially in Congo basin and Volta River basin
Term
What is the main vector of O. volvulus?
Definition
Simulium damnosum, which breed in fast-flowing streams
Term
What is the common symptom of onchocerciasis?
Definition
River blindness
Term
What are the clinical manifestations of O. volvulus due to?
Definition
Chronic inflammatory rxn to antigens to microfilariae
Term
What are the initial signs of O. volvulus?
Definition
fever, eosinophilia, urticaria, subcutaneous nodules, hanging groin
Term
What is the laboratory diagnosis for O. volvulus?
Definition
skin snip preparations from infrascapular or gluteal regions, incubated in saline, may also be seen in anterior chamber with aid of slit lamp in eye
Term
What is the treatment for O. volvulus?
Definition

Surgical removal

Treatment w/ivermectin

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