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250 Cards in this Set

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Gram Positive:

A normal inhabitant of the oral cavity, infection can be associated with dental procedures, with formation of lesions that erupt through the face with a purulent discharge
Actinomycetes isrealii

[Diagnosis is by finding sulfur granules = tangles of filaments of organisms wrapped in a matrix of calcium phosphate, imparting a yellow (sulfur) color to the abscess and discharge]
Gram Positive:

The most severe form of this disease results from the inhalation of spores with mediastinitis, pulmonary edema, and hemorrhage (Woolsorter's disease)
Bacillus anthracis

[Can occur as an occupational disease of textile or agricultural personnel resulting from contact with infected hides or wool; it has been used as an agent of biowarfare and bioterrorism]
Gram Positive:

Causes gastroenteritis and is typically associated with the consumption of reheated rice
Bacillus cereus

[Rapid emesis or diarrhea is associated with an enterotoxin that increases cAMP and is produced by the organism as it germinates]
Gram Positive:

Disease can be due to the ingestion of preformed toxin in home-canned foods or by the ingestion of spores in honey by an infant
Clostridium botulinum

[Symptoms include flaccid paralysis, dry mouth, diplopia, dysphagia, and respiratory failure]
Gram Positive:

Associated with the use of broad-spectrum antibiotics and the overgrowth of toxin-producing bacteria
Clostridium difficile

[Results in pseudomembranous colitis and is also a major nosocomial disease]
Gram Positive:

Causes gas gangrene and is often associated with automobile and motorcycle accidents
Clostridium perfringens

[Spores are abundant in soil and germinate in wounds; treatment includes surgical debridement, antibiotics, and hyperbaric oxygen]
Gram Positive:

Infection is associated with traumatic inoculation of spores that germinate and produce a toxin that causes spastic paralysis
Clostridium tetani

[The organism looks like a long rod with a dilated terminal end containing spore that resembles a tennis racquet]
Gram Positive:

Can cause risus sardonicus, the characteristic grimace of lockjaw
Clostridium tetani

[Treatment includes the use of antitoxins produced in horses or hyperimmunized humans, and antispasmodics such as benzodiazepines]
Gram Positive:

Causes gray pseudomembranes on the back of the throat
Corynebacterium diphtheriae

[Organisms often viewed in a "Chinese-letter" configuration]
Gram Positive:

A common cause of nosocomial infection, this organism is often resistant to many antibiotics, including vancomycin
Enterococcus spp.

[Common cause of urinary tract infections, sepsis, meningitis, and endocarditis]
Gram Positive:

Causes a fishy smelling vaginal discharge
Gardnerella vaginalis

[Histologically characterized by the presence of "clue cells," vaginal epithelial cells covered with bacteria, seen on a Pap smear]
Gram Positive:

As the dominant organism of normal vaginal flora, its metabolism helps maintain the low pH of the vagina
Lactobacillus spp.

[The lactic acid produced helps prevent the overgrowth of potentially pathogenic organisms; with the use of broad-spectrum antibiotics, such acid-producing flora is lost, allowing for overgrowth of pathogenic species]
Gram Positive:

This cause of late onset neonatal sepsis is a facultative intracellular parasite that spreads from cell to cell via actin rockets
Listeria monocytogenes

[This organism can be detected as short non-spore-forming rods with a tumbling end-over-end motility]
Gram Positive:

As well as being gram positive, this organism is also weakly acid fast and causes a pneumonia predominantly in immunocompromised patients
Nocardia asteroides

[This aeroic bacteria with filamentous growth is a common soil organism]
Gram Positive:

Part of the microbial flora of the skin, this bacilli contributes of the development of acne
Propionibacterium acnes

[The organism produces lipases that split fatty acids that cause inflammation, resulting in the formation of comedones]
Gram Positive:

A major cause of acute bacterial endocarditis, especially in IV drug users
Staphylococcus aureus

[Unlike subacute bacterial endocarditis, this organism can cause infection of undamaged heart valves, typically on the right side (tricuspid) in IV drug users]
Gram Positive:

A major cause of abscesses, furuncles, carbuncles, and other skin infections such as impetigo
Staphylococcus aureus

[This beta-hemolytic cocci grows in grape-like clusters, produces coagulase, and grows in culture as yellowish colonies]
Gram Positive:

Part of the normal flora of the skin, it causes infection of IV lines and catheters; it is a major cause of endocarditis in patients with prosthetic heart valves
Staphylococcus epidermidis

[Similar to Staphylococcus aureus, but grows as white colonies, does not produce coagulase, does not ferment mannitol, and does not produce Protein A]
Gram Positive:

The second leading cause of urinary tract infection in sexually active women
Staphylococcus saprophyticus

[Differentiated from Staphylococcus epidermidis by its ability to ferment mannitol and its resistance to novobiocin]
Gram Positive:

An important cause of neonatal sepsis and meningitis
Streptococcus agalactiae (Group B)

[This beta-hemolytic, bacitracin-resistant cocci is a normal inhabitant of the female genital tract and can be acquired during vaginal delivery]
Gram Positive:

A major cause of dental caries
Streptococcus mutans

[A member of the viridans group, it is also alpha-hemolytic and optochin-resistant]
Gram Positive:

Lancet-shaped diplococci found in a rusty brown sputum
Streptococcus pneumoniae

[Causes >90% of all causes of lobar pneumonia]
Gram Positive:

The use of a quellung reaction helps differentiate between the 85 different capsular subtypes
Streptococcus pneumoniae

[This alpha-hemolytic, optochin-sensitive, bile-soluble coccus grows on sheep red blood cell agar; the vaccine contains at least 23 of these subtypes]
Gram Positive:

Infection results in rheumatic fever
Streptococcus pyogenes (Group A)

[Characterized by a constellation of symptoms including migratory polyarthritis, erythema marginatum, pancarditis, Syndeham chorea, and subcutaneous nodules]
Gram Positive:

A major cause of pharyngitis, infection can also result in other suppurative symptoms such as erysipelas, cellulitis, and impetigo
Streptococcus pyogenes (Group A)

[Infection with this beta-hemolytic, bacitracin-sensitive cocci can be serodiagnosed with the detection of host antibodies to bacterial DNase B and anti-streptolysin O (ASO)]
Gram Positive:

Infection can lead to the development of acute glomerulonephritis and mitral and aortic stenosis
Streptococcus pyogenes (Group A)

[Immunocomplex deposition in the kidney visualized by "lumpy bump" immunofluorescence; cross-reactive antibodies to the bacteria result in autoimmune destruction of the heart valves]
Gram Positive:

Leading cause of subacute bacterial endocarditis
Streptoccus viridans

[This alpha-hemolytic, optochin-resistant cocci is part of the normal flora of the human pharynx]
Gram Positive:

Chronic exposure to this group of organisms leads to the development of hypersensitivity pneumonitis, including Farmer's Lung, Pigeon breeder's Lung, and Humidifier Lung
Thermophilic Actinomycetes

[Exposure causes an immunologically mediated interstitial fibrosis, bronchiolitis, and granuloma formation with progresive respiratory failure and cyanosis]
Gram Positive:

The organism is detected as PAS+ rods within the macrophages of the lamina propria of the small intestine
Tropheryma whippelii

[The causative agent of Whipple's disease that results in abdominal pain, malabsorption with diarrhea and weight loss, and a migratory polyarthritis]
Gram Negative:

Predominant organism in the human colon
Bacteroides fragilis

[Most often the cause of serious anaerobic infection]
Gram Negative:

Transmitted by the bite, scratch, or lick of an infected cat, resulting in low grade fever and a characteristic enlargement of lymph nodes for several weeks
Bartonella henselae

[This is the causative agent of Cat scratch disease; infection of an immunocompromised patient can result in Bacillary angiomatosis, cranberry-like pustules resembling Kaposi's sarcoma]
Gram Negative:

Causes a paroxysmal cough ending with an inspiratory "whoop" as air rushes over the swollen glottis
Bordetella pertussis

[The vaccine includes the purified virulence factors filamentous hemagglutinin (FHA) and pertussis toxoid, and is administered at 2, 4, 6, and 18 months along with the vaccine for Corynebacterium diphtheriae and Clostridium tetani in the DaPT vaccine
Gram Negative:

Transmitted by contaminated livestock and unpasteurized dairy products, infection results in a fever that rises in the morning and falls at night (Undulant fever)
Brucella spp.

[This granulomatous infection invades the reticulo-endothelial cells of the lymph nodes, liver, spleen, and bone marrow]
Gram Negative:

Endemic to tropical nations, this sexually transmitted organism results in granulomatous genital ulcers (pseudouboes) with the potential for autoamputation of genitalia
Klebsiella granulomatis
(formerly Calymmatobacterium granulomatis)

[Diagnosis is based on finding intracellular organisms aggregated as 'Donovan Bodies"]
Gram Negative:

A common cause of bloody diarrhea, particularly in children in close contact with puppues and kittens, which serve as reservoirs
Campylobacter jejuni

[These rod-shaped organisms appear as "gull wing"-shaped colonies with a single flagellum]
Gram Negative:

Causes a bloody diarrhea and is associated with the consumption of undercooked meat and dairy products
Enterohemorrhagic Escherichia coli
(E. coli 0157:H7)

[This dysentery-like condition is due to the elaboration of verotoxins similar to Shiga toxin that causes cytotoxicity to the colonic mucosa]
Gram Negative:

Infection may result in hemorrhagic colitis progressing to the hemolytic uremic syndrome (HUS)
Enterohemorrhagic Escherichia coli
(E. coli 0157:H7)

[HUS is characterized by acute renal failure, microangiopathic hemolytic anemia, and thrombocytopenia in children]
Gram Negative:

Leading cause of urinary tract infections
Escherichia coli

[Other major causes of urinary tract infections include Proteus, Serratia, Enterococci, Klebsiella, Pseudomonas, and Staphylococcus saprophyticus]
Gram Negative:

Causes "Traveler's diarrhea" and is also a major cause of death in children of developing nations
Escherichia coli

[The enterotoxigenic strain produces a heat stable and a heat labile toxin that causes an explosive watery diarrhea with cramping, abdominal discomfort, and dehydration]
Gram Negative:

This zoonotic organism can be transmitted by the bite of a deerfly or tick, or through handling or consuming rabbit products, which are the reservoir
Francisella tularensis
(rabbit fever)

[Infection can result in necrotic ulcers at the site of entry: conjunctiva (oculoglandular), mouth (typhoidal), or lungs (pneumonic tularemia) with disseminated granulomatous lesions of the lung, spleen, and liver]
Gram Negative:

Organism closely associated with chronic gastritis and peptic ulcer disease
Helicobacter pylori

[Also associated with an increase in the development of gastric carcinoma and MALToma]
Gram Negative:

A sexually transmitted disease, results in painful genital ulcers (chancroid)
Haemophilus ducreyi

[Infection in the United States is rare, most infections occur in the tropics; painless ulcer = T. pallidum]
Gram Negative:

Infection with this coccobacillus causes epiglottitis, otitis media in children, sinusitis, meningitis, and pneumonia in older patients with chronic respiratory disease
Haemophilus influenzae

[Growth in culture of this organism requires Factor V (hemin) and Factor X (NAD), found in chocolate agar media]
Gram Negative:

Formerly a leading cause of infection in children, the incidence of infection has dramatically decreased with the introduction of a vaccine
Haemophilus influenzae

[Vaccine is composed of the capsular material, polyribitol phosphate (PRP), conjugated to diptheria toxin]
Gram Negative:

Major cause of aspiration pneumonia in alcoholics
Klebsiella pneumoniae

[Organism produces a large antiphagocytic capsule, giving it a mucoid appearance and producing a thick, bloody, "currant-jelly" sputum]
Gram Negative:

Paired, kidney bean-shaped diplococci within leukocytes in a urethral discharge
Neisseria gonorrhoeae

[Differentiated from N. meningitidis based on its ability to ferment glucose and maltose, whereas N. gonorrhoeae ferments glucose only]
Gram Negative:

Leading cause of septic arthritis
Neisseria gonorrhoeae

[Typically presents as monoarticular arthritis of the knee, ankle, or wrist after a bout of urethritis]
Gram Negative:

Infection of a neonate passing through an infected birth canal results in ophthamia neonatorum and purulent conjunctivitis
Neisseria gonorrhoeae

[Babies born in the United States receive a required administration of tetracycline, erythromycin, or silver nitrate drops to prevent this]
Gram Negative:

Sexually transmitted disease that can lead to pelvic inflammatory disease that then predisposes to ectopic pregnancy
Neisseria gonorrhoeae

[The second most common notifiable disease in the United States]
Gram Negative:

Leading cause of meningitis among mililtary recruits and dormitory settings
Neisseria meningitidis

[Patients with deficiencies in the complement components C6-9, "the membrane attack complex," are particularly susceptible to infection]
Gram Negative:

Septicemia resulting from this organism can result in progressive hypotension, disseminated intravascular coagulation, widespread vascular purpura, and bilateral adrenal hemorrhage
Neisseria meningitidis

[The shock and adrenocortical insufficiency of Waterhouse-Friderichsen Syndrome is rapidly fatal without antibiotic treatment]
Gram Negative:

This organism is transmitted through the bite of a domestic cat or dog and can result in an abscess, cellulitis, and osteomyelitis
Pasteurella multocida

[Short, encapsulated, bipolar staining organism is part of the nasopharyngeal flora of domestic dogs and cats]
Gram Negative:

Urease-positive organism that causes an alkaline urine predisposing to the formation of urinary calculi
Proteus spp.
(P. mirabilis and P. vulgaris)

[These highly motile organisms are often refractory to antibiotic treatment because they often become trapped within stones]
Gram Negative:

Major cause of pneumonia in burn patients and cystic fibrosis patients
Pseudomonas aeruginosa

[This obligate aerobe requires only trace elements for growth and is a major cause of nosocomial infections because it colonizes aspirators, water and ice dispensers, IV lines, and even dilute disinfectant solutions]
Gram Negative:

Infection can result in folliculitis, swimmer's ear, pneumonia, and sepsis with the development of characteristic skin lesions (Ecthyma gangrenosum)
Pseudomonas aeruginosa

[This organism grows well in water, especially in inadequately chlorinated hot tubs; culture results in green colonies resulting from pigments pyoverdin and pyocyanin, with a characteristic fruity odor]
Gram Negative:

Causes a self-limiting enterocolitis associated with the consumption of contaminated eggs and poultry
Salmonella enteritidis

[This highly motile organism requires a large infectious dose, which distinguishes it from Shigella spp.]
Gram Negative:

Causes an enteric fever with the development of characteristic "rose spots" on the abdomen
Salmonella typhi

[After recovery, a small percentage of patients may become carriers because the organisms colonize the gallbladder, a state that may require cholecystectomy]
Gram Negative:

This organism is a common cause of nosocomial infections; some strains produce a red pigment
Serratia marcescens

[Causes pneumonia, bacteremia, endocarditis, and is often multidrug-resistant]
Gram Negative:

Infection with a small dose of organisms results in dysentery that is only transmitted among humans with no animal reservoir
Shigella dysenteriae

[This cause of a bloody, mucoid, low-volume diarrhea can result in life-threatening dehydration and acidosis and is often associated with insanitary conditions]
Gram Negative:

Major cause of secretory diarrhea with life-threatening dehydration, particularly in developing nations
Vibrio cholerae

[These comma-shaped rods with a polar flagellum adhere to the intestinal mucosa and elaborate an exotoxin, but never invade]
Gram Negative:

Causes nausea, cramping, and is associated with the consumption of raw shellfish
Vibrio parahaemolyticus

[Although this free-living salt bacteria is related to Vibrio cholerae, the symptoms are much milder]
Gram Negative:

Rodents are the reservoir for this organism, transmitted by the bite of a flea, resulting in the plague
Yersinia pestis

[Transmission is also possible between humans in the case of the pneumonic plague]
Gram Negative:

Infection can result in pustules and enlargement of draining lymph nodes that rupture through the skin to form buboes
Yersinia pestis

[This organism displays bipolar staining resulting in a safety pin appearance]
Poorly Staining:

Late stages of infection may lead to a severe autoimmune arthritis, life-threatening heart block, and facial nerve palsy
Borrelia burgdorferi

[The vaccine was available for this organism to prevent development of Lyme disease, but was found to have autoimmune side effects and was withdrawn. There is a vaccine for dogs, and new vaccines are being researched using outer surface protein C (OspC) and glycolipoprotein as methods of immunization]
Poorly Staining:

Transmitted by the Ixodes tick bite that results in a characteristic bull's eye lesion (Erythema chronicum migrans)
Borrelia burgorferi

[Infection occurs mainly in the Northeast during the summer months, when the deer tick (Ixodes) is found]
Poorly Staining:

Transmitted by the human body louse, this organism causes relapsing fever
Borrelia recurrentis

[Causes a febrile disease that fades as antibodies develop and relapses as the organism undergoes antigenic variation of its variable major protein]
Poorly Staining:

Previously known as the TWAR agent, it is a common cause of sore throats and interstitial pneumonia
Chlamydia pneumoniae

[As with all Chlamydial species, it exists as either elementary bodies, the infectious form, or as intracellular reticular bodies, the metabolically active form]
Poorly Staining:

Causes an interstitial type pneumonia and is associated with exposure to contaminated parrots and parakeets and other domestic birds
Chlamydia psittaci

[The causative agent of Psittacosis, transmitted by birds of the psittacine family; a similar disease, Ornithosis, is also seen upon exposure to other birds such as pigeons, ducks, and chickens]
Poorly Staining:

This cause of chronic keratoconjunctivitis results in corneal scarring and is one of the leading causes of blindness worldwide
Chlamydia trachomatis

[Chlamydia tracomatis is divided into serovars based on serology and symptomatology; in this case, the pathology is due to C. trachomatis A, B, an C]
Poorly Staining:

This organism is the leading cause of sexually transmitted bacterial disease, resulting in urethritis, cervicitis, salpingitis, and neonatal conjunctivitis
Chlamydia trachomatis

[Infection in a female can progress to pelvic inflammatory disease, resulting in the potential for ectopic pregnancy or sterility]
Poorly Staining:

This organism is closely associated with the development of conjunctivitis, urethritis, and arthritis (Reiter's syndrome)
Chlamydia trachomatis

[This autoimmune phenomenon resulting from cross-reactive antigens between the organism and affected tissues is associated with the HLA-B27]
Poorly Staining:

Causes Lymphogranuloma venereum, characterized by nodules and vesicles on the genitals, venereal buboes, and elephantiasis of the genitals with rectal strictures
Chlamydia trachomatis

[Results from infection of the most invasive serovars L1, L2, and L3; this sexually transmitted disease progresses through primary, secondary, and tertiary stages]
Poorly Staining:

Causes Q fever, an interstitial pneumonia, resulting from the inhalation of the organism
Coxiella burnetii

[Unlike other rickettsial diseases, this organism is not transmitted by the bite of an arthropod, does not cause a rash, and cannot be detected by the classical serologic test for Rickettsia, the Weil-Felix Test]
Poorly Staining:

This organism grows in warm, moist environments (contaminated air conditioner systems) and causes a potential life-threatening pneumonia in patients with lung disease
Legionella pneumophila

[This organism, often visualized with Dieterle silver stain, also causes a less severe form of pneumonia known as Pontiac fever]
Poorly Staining:

One of the most common opportunistic bacterial infections in AIDS patients
Mycobacterium avium-intacellulare (MAC)

[This disease presents similarly to TB and is acquired from soil, birds, or other animals]
Poorly Staining:

Infection results in the destruction of skin and cartilage, resulting in a leonine facies and limb deformities
Mycobacterium leprae

[Leprosy, or Hansen disease, presents as a spectrum between two extremes, from tuberculoid leprosy associated with good prognosis to lepromatous leprosy, in which numerous acid-fast bacilli are stuffed in macrophages = Lepra cells]
Poorly Staining:

Infection results in the destruction of peripheral nerves, resulting in anesthesia followed by atrophy and autoamputation
Mycobacterium leprae

[This acid-fast bacilli has a long generation time, approximately 13 days, and cannot be cultivated in the laboratory]
Poorly Staining:

Primary infection results in subpleural parenchymal lesions and enlarged caseous lymph nodes (Ghon complex) and reactivation can result in cavitary lesions in the upper lung lobes
Mycobacterium tuberculosis

[Diagnosis is confirmed by finding acid-fast bacilli in the sputum or in cultures that take several weeks to grow]
Poorly Staining:

The classic presentation of infection with this organism includes fever, night sweats, fatigue, and weight loss
Mycobacterium tuberculosis

[Presents similarly to other granulomatous infections such as histoplasmosis or coccidiodomycosis]
Poorly Staining:

Infection can result in the involvement of vertebrae (Pott's disease) with spread to form a psoas abscess and, in immunocompromised patients, overwhelming miliary dissemination
Mycobacterium tuberculosis

[Although rare in the United States, incidences of infections are increasing in immunocompromised patients and urban populations, with high incidence of multidrug-resistant strains]
Poorly Staining:

Immunization employs the use of Bacillus Calmette Guerin (BCG), one of the few live attenuated bacterial vaccines available
Mycobacterium tuberculosis

[The test for exposure to TB involves injection of a small amount of partially purified derivative (PPD) and detecting a delayed type hypersensitivity reaction; recipients of the vaccine (an attenuated strain of M. bovis) have a positive PPD]
Poorly Staining:

A prominent cause of community-acquired pneumonia, symptoms normally include a hacking, nonproductive cough (atypical pneumonia)
Mycoplasma pneumonia

[One of the smallest free-living bacteria, has no cell wall, and causes an interstitial inflammation rather than intra-alveolar exudates]
Poorly Staining:

Causes "Walking pneumonia" with the potential to develop a self-limiting hemolytic anemia
Mycoplasma pneumoniae

[Untreated patients develop IgM autoantibodies to red blood cells, termed acute cold agglutinins]
Poorly Staining:

Associated with overcrowding and transmitted by the human body louse, this organism causes Epidemic typhus
Rickettsia prowazekii

[Characterized by extreme fever, myalgias, and a rash; a less sever form of the disease, Endemic typhus, results from Rickettsia typhi]
Poorly Staining:

Transmitted by ticks, infection results in a petechial rash with involvement of the palms and soles
Rickettsia rickettsii

[The causative agent of Rocky Mountain spotted fever is an obligate intracellular organism seen with Giemsa staining; despite its name, it is endemic to the eastern United States]
Poorly Staining:

Transplacental infection can result in a triad of interstitial keratitis, Hutchinson teeth, and 8th cranial nerve deafness
Treponema pallidum

[Infection results in osteochondritis and periostitis and contributing as well to other defects such as destruction of the vomer, leading to saddle nose deformity; other bone defects include mulberry molars and saber shin deformities]
Poorly Staining:

Long-term consequences of untreated disease include tabes dorsalis and aneurysms of the ascending aorta
Treponema pallidum

[Tertiary syphilis can lead to paresis and is the leading cause of aneurysms of the ascending aorta with a characteristic tree-barking appearance]
Poorly Staining:

The disease can manifest with a maculopapular rash on the palms and soles, and condyloma lata
Treponema pallidum

[Secondary syphilis presents with a rash and gray flattened wart-like lesions on the anogenital, axillary, and oral areas; these condyloma lata are not to be confused with condyloma acuminatum seen with HPV infection]
Poorly Staining:

Initial infection presents with a painless ulcer on the genitals known as a chancre
Treponema pallidum

[The characteristic lesion of primary syphilis is highly contagious and contains numerous spirochetes viewed by dark field light microscopy or by immunofluorescent microscopy]
Poorly Staining:

Patients with SLE are often positive for serologic tests for this organism even if not infected (biologic false positive)
Treponema pallidum

[Screening test like the rapid plasma reagin or Venereal Disease Research Laboratory (VDRL) are based on finding antibodies to cardiolipin, which patients with SLE make; the most specific test is the fluorescent treponemal antibody (FTA-Abs test)]
Poorly Staining:

The organism is exquisitely sensitive to penicillins; treatment can result in rash, fever, and hypotension (Jarisch-Herxheimer reaction)
Treponema pallidum

[Treatment results in rapid death of the organism with release of toxic products that cause symptoms that can be relieved by anti-inflammatory agents]
Poorly Staining:

This organism that lacks a cell wall is the cause of recurrent urinary tract infections
Ureaplasma urealyticum

[Related to Mycoplasma pneumoniae, infection is associated with the development of urinary calculi]
Virulence Factors:

Produces a trivalent exotoxin composed of protective antigen, edema factor, and lethal factor
Bacillus antracis

[Protective antigen mediates cell binding, edema factor is a secreted adenylate cyclase, and lethal factor causes CNS depression]
Virulence Factors:

One of the virulence factors of this organism is an anti-phagocytic capsule composed of D-glutamic acid
Bacillus anthracis

[Although typically composed of polysaccharides, other organisms with unique capsular components include sialic acid in Streptococcus agalactiae and hyaluronic acid in Pasteurella multocida]
Virulence Factors:

Produces a typical AB toxin that catalyzes the transfer of ADP-ribose from NAD⁺ to the inhibitory G protein subunit (Gi)
Bordetella pertussis

[Interference of G protein-coupled receptors such as those employed by chemokines results in significant lymphocytosis; other virulence factors include filamentous hemagluttinin and tracheal cytotoxin]
Virulence Factors:

Produces and exotoxin that blocks the release of actylcholine at the neuromuscular junction
Clostridium botulinum

[Treatment includes the used of an antitoxin produced in horses, with the possibility of serum sickness]
Virulence Factors:

The toxin produced by this organism can be used in minute amounts to treat dystonias, strabismus, and wrinkles
Clostridium botulinum

[Toxin causes a flaccid paralysis of the injected muscles]
Virulence Factors:

Produces and AB toxin that ADP-ribosylates the small GTP binding protein Rho
Clostridium difficile

[Results in the depolymerization of the cytoskeleton with necrosis of the colonic epithelium]
Virulence Factors:

Produces a lecithinase and hyaluronidase that results in cellulitis and myonecrosis
Clostridium perfringens

[The lecithinase can be demonstrated by culturing on egg yolk agar; normally the organism produces a double zone of hemolysis on blood agar]
Virulence Factors:

The toxin elaborated by this organism inhibits the release of the inhibitory neurotransmitters, GABA and glycine, resulting in a spastic paralysis
Clostridium tetani

[The DaPT vaccine includes the highly immunogenic tetanus toxoid; a booster is recommended every 10 years and also after a puncture wound]
Virulence Factors:

A virulence factor produced by these two organisms is a typical AB toxin that catalyzes the transfer of ADP-ribose from NAD⁺ to elongation factor-2
Corynebacterium diptheria and Pseudomonas aeruginosa

[ADP ribosylation of EF-2 (elongation factor-2) results in the inhibition of protein synthesis and death of the cell]
Virulence Factors:

Produces a heat stable toxin Sta, that stimulates the production of cGMP, with similar effects to those of increased cAMP
Enterotoxigenic Escherichia coli

[In addition, the organism produces a STb toxin that is cyclic nucleotide independent]
Virulence Factors:

Virulence factor found in the outer leaflet of the cell wall of gram-negative organisms
Lipopolysaccharide (LPS)

[Composed of Lipid A, a core polysaccharide, and O antigen, LPS leads to activation of macrophages with the release of IL-1, with the development of disseminated intravascular coagulation and septic shock]
Virulence Factors:

The virulence factors associated with this organism include the ability to grow intracellularly and the production of cord factor
Mycobacterium tuberculosis

[Cord factor is thought to contribute to the formation of granulomas]
Virulence Factors:

Produces a toxin that irreversible inactivates the 60S ribosomal subunit with the cessation of protein synthesis and cell death
Shigella dysenteriae

[Toxins similar to Shiga toxin are produced by enterohemorrhagic E. coli and are known as verotoxins]
Virulence Factors:

Produces exfoliant toxin
Staphylococcus aureus

[The toxin causes an exfoliative dermatitis, Scalded skin syndrome, that appears as a sunburn-like rash]
Virulence Factors:

Produces Toxic shock syndrome toxin
Staphylococcus aureus

[Toxic shock syndrome, associated with the use of superabsorbent tampons, results from the production of this toxin, which causes polyclonal activation of T cells through antigen-independent activation of the T-cell receptor]
Virulence Factors:

Protein A is a major virulence factor
Staphylococcus aureus

[Binds to the Fc region of the antibody, preventing complement fixation and phagocytosis]
Virulence Factors:

The three major pyogens for which a polysaccharide capsule is the major virulence factor
Streptococcus pneumoniae
Haemophilus influenzae
Neisseria meningitidis

[The capsule prevents opsonization by host cell immunoglobulins]
Virulence Factors:

Produces erythrogenic toxin, resulting in Scarlet fever
Streptococcus pyogenes (Group A)

[Erythrogenic toxin is a phage-encoded superantigen that causes the rash often accompanying pharyngitis]
Virulence Factors:

M antigen is the most important virulence factor
Streptococcus pyogenes (Group A)

[Prevents phagocytosis, and antibodies to this molecule underlie the long-term sequelae of infection, namely chronic rheumatic heart disease]
Virulence Factors:

Produces an AB toxin that transfers ADP-ribose from NAD⁺ to the stimulatory G protein subunit (Gs)
Vibrio cholerae

[Similar to the labile toxin (LT) of enterotoxigenic E. coli, this toxin results in the increase of cAMP with hypersecretion of Cl⁻ and HCO₃⁻ with the osmotic reflux of up to 30 L of water/day]
Fungi:

Produces a toxin that results in liver damage upon ingestion of wild mushrooms
Amanita species

[Ingestion may result in life-threatening fulminant hepatitis, requiring liver transplant]
Fungi:

Produces the carcinogen aflatoxin and is a common contaminant of moldy nuts and grains
Aspergillus favus

[Aflatoxins contribute to the development of hepatocellular carcinoma and act synergistically with HBV to promote carcinogenesis]
Fungi:

Proliferation of this organism within the lung causes a "fungus ball" that must be removed surgically
Aspergillus fumigatus

[Microscopically the organism grows as septate hyphae, branching at 45º angles]
Fungi:

Although an opportunistic mycosis, it can cause hypersensitivity pneumonitis such as Farmer's Lung
Aspergillus fumigatus

[Resulting from inhalation of moldy hay]
Fungi:

Systemic mycosis that begins as lower respiratory tract infection and may disseminate to cause warty-like skin lesions
Blastomyces dermatiditis

[Results in granulomatous lung lesions similar to tuberculosis; may also result in skeletal and genitourinary manifestations]
Fungi:

Systemic mycosis endemic to the southeastern United States
Blastomyces dermatitidis

[Fungi appears in infected tissue as yeast with broad-based budding]
Fungi:

Causes a cottage cheese-like vaginal discharge
Candida albicans

[Predisposing factors include immunosuppression, diabetes, obesity, and the use of broad-spectrum antibiotics]
Fungi:

Causes white curd-like patches on mucocutaneous membranes of the mouth and extend downward to cause esophagitis in immunocompromised patients
Candida albicans

[In addition to causing thrush, C. albicans is a common cause of tinea unguium (fungal infection of the nails) and diaper rash]
Fungi:

Most common mycotic pathogen
Candida albicans

[Although a yeast, it can form pseudohyphae in infected tissue and form characteristic germ tubes at 37ºC under laboratory conditions]
Fungi:

Systemic mycosis endemic to the San Joaquin Valley in southern California
Coccidioides immitis

[Causes "Valley Fever," characterized by arthralgias, cough, and fever]
Fungi:

Found within infected tissue as spherules that rupture to release endospores
Coccidioides immitis

[Dimorphic fungi with contraction of infection by inhalation of arthrospores in the sand and soil]
Fungi:

The only mycotic pathogen with a capsule
Cryptococcus neoformans

[Visualized with an India ink test; capsule excludes ink, providing contrast]
Fungi:

Causes meningitis in patients with underlying immunodeficiency, especially AIDS
Cryptococcus neoformans

[Associated with pigeon droppings, this fungus grows within the Virchow-Robin vascular spaces of the brain, resulting in "soap bubble lesions"]
Fungi:

Causes cutaneous infections such as tinea corporis, tinea cruris (jock itch), and tinea pedis (athlete's foot)
Dermatophytes

[Typically caused by dermatophytes of the genera Trichophyton spp. and result in scaly hypo- or hyperpigmented annular pruritic lesions]
Fungi:

Associated with the inhalation of spores from bird or bat droppings in the Ohio and Mississippi River Valley
Histoplasma capsulatum

[Histologically characterized by macrophages stuffed with numerous yeast cells]
Fungi:

Causes tinea versicolor, which manifests as patches of hyper- and hypopigmentation on the trunk
Malassezia furfur

[Found in skin scales and has a characteristic spaghetti and meatballs appearance (yeast clusters and short, curved septate hyphae)]
Fungi:

Most common pulmonary mycotic infection with symptoms ranging from asymptomatic to tuberculosis-like symptoms
Histoplasma capsulatum

[In immunocompetent individuals, infection often resolves, with calcification of hilar lymph nodes]
Fungi:

Most common cause of tinea capitis, ringworm of the scalp
Microsporum canis

[Common in prepubescent children with pets; the natural inhibitor or Microsporum spp. growth, undecylenic acid, is produced in the sebum of postpubertal individuals]
Fungi:

Results in rhinocerebral disease, primarily in patients with diabetic ketoacidosis or leukemia
Mucor and Rhizopus species

[Distinct from other human fungal pathogens in that these species cause disease in their sexual life cycle and display nonseptate hyphae branching at a 90º angle or wider]
Fungi:

This organism grows as multiple budding yeasts that appear as a "captains wheel" and causes disease almost exclusively in men
Paracoccidioides braziliense (brasiliensis)

[This granulomatous lung disease occurs primarily in Central and South America, with >90% of cases seen in males]
Fungi:

Causes an alveolar pneumonia, typically in AIDS patients
Pneumocystis (carinii) jirovecii

[Previously thought to be a protozoa, this fungus causes a foamy, amorphous alveolar exudate and is seen as cup- or boat-shaped cysts upon staining with silver methenamine]
Fungi:

Causes the most common subcutaneous mycosis, Rose handler's disease
Sporothrix schenckii

[Transmitted by the prick of a contaminated thorn; treated with a dilute solution of potassium iodide (KI) in milk]
Protozoa:

Transmitted by the same tick as that which carries Lyme disease, infection results in similar manifestation as malaria
Babesia microti

[Often mistaken for P. falciparum, the organism can be detected in RBCs as a "Maltese cross," which is diagnostic]
Protozoa:

Causes a self-limiting diarrhea in immunocompetent individuals or life-threatening intractable diarrhea in AIDS patients
Cryptosporidium parvum

[Infection is associated with the consumption of water contaminated with infected animal feces]
Protozoa:

Dissemination to the liver can result in abscess formation with a characteristic anchovy paste aspirate
Entamoeba histolytica

[The organism can form an amoeboma with the potential for penetration of the serosa and peritonitis]
Protozoa:

Common cause of amebic dysentery, infection leads to the formation of flask-shaped ulcers in the colonic mucosa
Entamoeba histolytica

[The finding of trophozoites with ingested RBCs is pathognomonic]
Protozoa:

The only common pathogenic protozoa of the small intestine
Giardia lamblia

[A heart-shaped symmetrical trophozoite with two nuclei, four pairs of flagella, and a large sucking disk for adherence to the mucosal surface]
Protozoa:

Causes flatulence and diarrhea with steatorrhea and the production of bulky greasy foul-smelling stool
Giardia lamblia

[Infection is more common among day-care children, campers consuming contaminated stream water, and homosexuals engaging in oral-anal contact]
Protozoa:

Infection with different species results in dermal, mucocutaneous, and visceral forms of the disease
Leishmania spp.

[Dermal leishmaniasis is due to L. tropica, the mucocutaneous form is due to L. braziliensis, and the most severe form, visceral leishmaniasis, is due to L. donovani and can result in skin hyperpigmentation of kala-azar]
Protozoa:

Transmitted by the sandfly, the amastigote stage survives and multiplies within macrophages
Leishmania spp.

[The only protozoan parasite capable of replication within the phagolysosomes of reticuloendothelial cells]
Protozoa:

Free-living flagellated amoeba, acquired by swimming in freshwater ponds, causing a fulminant meningoencephalitis with death within a week
Naegleria fowleri

[Another free-living amoebum, Acanthamoeba castellani, causes less severe disease, typically limited to corneal ulceration and keratitis]
Protozoa:

Blackwater fever
Plasmodium falciparum

[Seen in P. falciparum malaria, in which infected cells are abnormally adherent and cause thrombosis and ischemia with hemolysis, resulting in hemoglobinuria]
Protozoa:

Transmitted by the female Anopheles mosquito, with infection of RBCs and hepatocytes
Plasmodium spp.

[An obligate intracellular parasite, Plasmodium is typically seen as ring- or crescent-shaped forms within RBCs on a Giemsa-stained peripheral blood smear]
Protozoa:

Some resistance to infection is provided to patients with sickle cell disease/trait, glucose-6-phosphate dehydrogenase deficiency, and thalassemia
Plasmodium spp.

[Symptoms of malaria include cyclic fevers (every 48 hr = P. falciparum, every 72 hr = P. malariea), headache, anemia]
Protozoa:

Exposure of nonimmune mothers results in fetal transmission with the potential for stillbirth and intracerebral calcifications
Toxoplasma gondii

[Infection may be acquired from cysts in raw or undercooked meat or aerosolization of infected cat feces from litter boxes]
Protozoa:

Usually asymptomatic in immunocompetent individuals, infection in an AIDS patient can result in fulminant, life-threatening encephalitis
Toxoplasma gondii

[Visualized radiographically as a ring-enhancing mass on CT scan; other ring-enhancing masses include cerebral abscess and Glioblastoma multiforme]
Protozoa:

A common cause of vaginitis, it often presents with vulvo-vaginal pruritis, with a profuse frothy discharge
Trichomonas vaginalis

[Causes strawberry mucosa, spotty reddening and edema of the affected mucosa]
Protozoa:

Identified as pear-shaped, flagellated trophozoites with undulating movements on a wet-mount slide of vaginal or urethral discharge
Trichomonas vaginalis

[Typically a sexually transmitted disease, growth is associated with an abnormally alkaline pH of the vagina]
Protozoa:

Transmitted by the tsetse fly, this protozoa causes African sleeping sickness, characterized by cyclic fevers, encephalitis, slurred speech, and somnolence
Trypanosoma brucei

[The organism evades the immune system by genetic rearrangement of its variable surface glycoprotein (VSG)]
Protozoa:

Can destroy the myenteric plexus, resulting in mega-esophagus and megacolon
Trypanosoma cruzi

[Transmitted by the droppings of the reduviid bug ("kissing bug"), often with the initial development of unilateral swelling of the eyelids (Romana's sign)]
Protozoa:

A major cause of heart disease in Central and South America
Trypanosoma cruzi

[Acute forms of Chagas disease lead to direct invasion of the myocardium with inflammation; the chronic forms of disease involve autoimmune destruction with the development of dilated cardiomyopathy with life-threatening arrhythmias]
Helminths:

Chronic infection with this hookworm constitutes an important cause of anemia worldwide
Ancylostoma duodenale ("hookworm")

[Leads to iron deficiency anemia because each worm consumes as much as 0.25 ml blood/day]
Helminths:

Migration of larval nematodes below the skin results in serpiginous urticarial trails on the skin (Creeping eruptions)
Ancylostoma braziliense and other animal hookworms

[Infection is acquired by contact with sand-containing feces of dogs and cats]
Helminths:

Most common helminth infection in humans worldwide
Ascaris lumbricoides

[As much as ¼ of the world population is infected; infection causes GI obstruction, granulomas of the biliary tree, liver abscesses, and hypersensitivity pneumonitis]
Helminths:

Infection is associated with damage to the biliary tract and development of cholangiocarcinoma
Clonorchis sinensis

[Associated with the consumption of infected freshwater fish]
Helminths:

Infection can be associated with megaloblastic anemia
Diphyllobothrium latum

[This enormous fish tapeworm absorbs dietary vitamin B₁₂, resulting in B₁₂ deficiency in the host]
Helminths:

Removal of this nematode is traditionally accomplished by slowly twisting it around a stick to remove it from beneath the skin
Dracunculus medinensis

[Infection is acquired by consuming water contaminated by the intermediate host, the cyclops, a microscopic crustacean]
Helminths:

Larvae form large space-occupying hydatid cysts in the liver and lung, and leakage of fluid can result in anaphylaxis
Echinococcus granulosus (dog tapeworm)

[Because herbivores such as sheep are usually an intermediate host for the dog tapeworm, infection commonly presents in the context of a sheep farmer with many sheepdogs]
Helminths:

Causes perianal pruritis, http://www.flashcardexchange.com/mycards/add/1342617with diagnosis confirmed by the recovery of eggs from the anus with scotch tape
Enterobius vermicularis (pinworm)

[Most common helminth infection in the United States and often associated with day-care institutions]
Helminths:

Infection results in subcutaneous "caliber/calabar" swellings and can be seen migrating across the eye beneath the conjunctiva
Loa loa filariasis

[Infection is transmitted by the bite of a mango fly, Chrysops]
Helminths:

Endemic to Africa, especially along river basins, infection can result in River blindness
Oncocerca volvulus

[Transmitted by the blackfly, this nematode also causes loss of elasticity of the skin with significant dependent edema (i.e. hanging groin)]
Helminths:

Infection of the bladder is associated with the development of squamous cell carcinoma of the bladder
Schistosoma hematobium

[Endemic to Egypt and Sudan and associated with wading through moist soil while barefoot; diagnosis is confirmed by finding spherical eggs with a terminal spine in the urine]
Helminths:

The smallest of all intestinal nematodes, high worm burden is possibly the result of autoinfection
Strongyloides stercoralis

[It is the only intestinal nematode capable of completing its life cycle within the human host]
Helminths:

One of the most common cestode infections in the United States, and associated with the consumption of improperly cooked contaminated beef
Taenia saginata (beef tapeworm)

[Usually results in vague abdominal pain, although the tapeworm can grow to several meters in length]
Helminths:

Infection with the larval form of this tapeworm from feces-contaminated water can lead to cysticercosis
Taenia solium (pork tapeworm)

[Results in the growth of the larvae in brain, resulting in a Swiss cheese appearance of the cerebral hemispheres]
Helminths:

Accidental transmission of these nematodes from pet feces (in sandboxes or on sandy beaches) results in Visceral larva migrans
Toxocara canis and Toxocara cati

[Symptoms include eosinophilia, pneumonitis, and vision loss]
Helminths:

Infection is acquired by consuming cysts in undercooked, contaminated pork
Trichinella spiralis

[Infection results in flu-like symptoms, diarrhea, myalgias, and periorbital edema]
Helminths:

Rectal prolapse is a potential complication in children resulting from straining during defecation with infection of this nematode
Trichuris trichiura (whipworm)

[Diagnosis is based on finding bile-stained, barrel-shaped eggs with polar plugs]
Helminths:

Filariasis (Elephantiasis)
Wucheria bancrofti

[Organism causes obstruction of lymph vessels resulting in edema with swelling of the legs and genitalia]
DNA Viruses:

Major cause of epidemic conjunctivitis (pink eye)
Adenovirus

[Various subtypes are also associated with pharyngitis and gastroenteritis]
DNA Viruses:

Major cause of retinitis, leading to blindness in an immunocompromised patient
Cytomegalovirus (CMV)

[Can cause life-threatening interstitial pneumonia in such patients and heterophil-negative infectious mononucleosis in immunocompromised individuals]
DNA Viruses:

Most common viral cause of congenital abnormalities in the United States
Cytomegalovirus (CMV)

[Infected cells display characteristic "owl eye" intranuclear viral inclusions]
DNA Viruses:

Infection results in the production of heterophil antibodies
Epstein-Barr Virus (EBV)

[Viral infection results in the polyclonal activation of B cells with the production of antibodies to sheep RBCs (heterophil antibodies) that can be detected with the monospot test]
DNA Viruses:

Major cause of infectious mononucleosis
Epstein-Barr Virus (EBV)

[Characterized by weeks of fever, malaise, and lymphadenopathy, the peripheral blood contains an abundance of atypical lymphs, which are T cells that recognize EBV-infected cells]
DNA Viruses:

Infection is associated with Burkitt's lymphoma and nasopharyngeal carcinoma
Epstein-Barr virus (EBV)

[Burkitt's lymphoma is more commonly associated with EBV in Africa; nasopharyngeal carcinoma is more common in patients from Asia]
DNA Viruses:

This virus encodes an RNA-dependent DNA polymerase (reverse transcriptase)
Hepatitis B Virus (HBV)

[The virus produces its DNA genome through a single mRNA transcript, requiring the presence of a reverse transcriptase]
DNA Viruses:

Appear in the serum as Dane particles and as large amounts of filaments of excess surface antigen
Hepatitis B Virus (HBV)

[The surface antigen (HBsAg) is produced by recombinant DNA technology and is given as a vaccine]
DNA Viruses:

A major cause of hepatocellular carcinoma worldwide
Hepatitis B Virus (HBV)

[Although less likely to progress to either cirrhosis or carcinoma than is HCV, the worldwide prevalence especially in Africa makes HBV the leading cause]
DNA Viruses:

Major cause of sexually transmitted and vertically transmitted hepatitis
Hepatitis B Virus (HBV)

[Histologically, infected cells appear as ground glass hepatocytes because of the presence of excess surface antigen within the cytoplasm]
DNA Viruses:

Infection with this virus is a leading cause of corneal blindness in the United States
Herpes simplex virus-1 (HSV-1)

[Keratoconjunctivitis results in dendritic ulcers that can be visualized with fluorescein staining]
DNA Viruses:

Infection results in Cowdry Type A intranuclear inclusions and multinucleated giant cells
Herpes simplex virus-1 (HSV-1)

[One of the most common human viral infections, the virus enters broken skin and remains latent in the trigeminal ganglion, with spontaneous reactivation triggered by axonal injury, stress, or UV light]
DNA Viruses:

Leading cause of sporadic encephalitis in the United States
Herpes simplex virus-1 (HSV-1)

[Commonly affects the temporal lobe]
DNA Viruses:

Most common cause of vesiculo-ulcerative lesions on the penis or vagina
Herpes simplex virus-2 (HSV-2)

[Reactivation of the virus is common because the virus remains latent in the lumbar and sacral ganglia; detected using the Tzanck test]
DNA Viruses:

Infection causes Roseola infantum or Sixth disease
Herpes Virus 6

[A common, mild, childhood disease characterized by high fever and a skin rash]
DNA Viruses:

Causes cranberry-pigmented lesions on AIDS patients
Herpes Virus 8

[Kaposi sarcoma is a tumor of blood vessels characterized by a disarray of vascular channels filled with RBCs]
DNA Viruses:

Infection is linked to premalignant lesions on the vulva, cervix, penis, and anus
Human papilloma virus (HPV)

[Viral oncoprotein E6 binds to p53 and viral oncoprotein E7 binds to Rb, stimulating infected cells to undergo uncontrolled growth]
DNA Viruses:

Infection of keratinized tissue results in the formation of warts on the hands and feet
Human papilloma virus (HPV)

[Typically caused by infection with HPV 1-4, with the development of warts on the hands (Verruca Palmaris) and feet [Verruca Plantaris)]
DNA Viruses:

Infection causes cauliflower-like lesions on the external genitals or perianal areas
Human Papilloma Virus (HPV)

[Condyloma acuminatum is microscopically characterized by the presence of vacuolated infected cells, termed koilocytes]
DNA Viruses:

Reactivation of latent viral infection in immunocompromised patients can result in Progressive multifocal leukoencephalopathy (PML)
JC Virus

[This polyomavirus causes foci of demyelination surrounded by oligodendrocytes with viral inclusions]
DNA Viruses:

This contagious virus causes benign epithelial tumors that appear as pearly, umbilicated nodules with a central caseous plug
Molluscum contagiosum

[These lesions caused by the pox virus occur as clusters on the trunk, genitalia, and extremities; it is transmitted by towels, barbers, swimming pools, and sexual activity]
DNA Viruses:

Causes aplastic crisis in patients with sickle cell anemia, thalassemias, and acquired hemolytic anemias
Parvovirus B19

[Virion replicates best in rapidly dividing erythroblasts, resulting in cell lysis]
DNA Viruses:

Infection of a child results in a "slapped cheek" appearance
Parvovirus B19

[This single-stranded DNA virus causes Erythema infectiosum or Fifth disease]
DNA Viruses:

The only DNA virus that replicates solely in the cytoplasm and that carries its own DNA-dependent polymerases
Poxvirus

[The largest of all viruses, it appears brick-shaped by electron microscopy, and causes characteristic Guarnieri inclusion bodies when replicating in cells]
DNA Viruses:

Found as a contaminant in preparations of polio vaccines produced in monkey cell culture
SV40

[This polyoma virus is typically a simian virus, which can cause tumors in mice, although no pathogenic effects have been reported in humans]
DNA Viruses:

Causes chickenpox upon initial infection, and shingles upon reactivation
Varicella-zoster virus (VZV)

[The only herpes virus with a live attenuated vaccine; reactivation most commonly occurs along the dermatomal distribution of the ophthalmic division of the trigeminal nerve]
DNA Viruses:

Infection results in the successive appearance of macules, papules, vesicles, and crusts all seen simultaneously
Varicella-zoster virus (VZV)

[Severe infection can result in pneumonia with multinucleated giant cells]
DNA Viruses:

Associated with Reye syndrome when the accompanying fever is treated with aspirin
Varicella-zoster virus (VZV)

[Reye syndrome is an acute encephalopathy associated with fatty infiltration of the liver, which is often fatal]
RNA Viruses:

Group of Togaviruses transmitted by mosquitoes leading to encephalitis
Alphavirus

[This genus includes Eastern equine encephalitis virus (EEE), Western equine encephalitis virus (WEE), and Venezuelan equine encephalitis (VEE)]
RNA Viruses:

A grouping of viruses that are transmitted by mosquitoes and ticks
Arboviruses

[The group contains members of the Flavavirus family, Togavirus family, and Bunyavirus family]
RNA Viruses:

Only bunyavirus member causing diseases endemic to the United States
California encephalitis virus
(including La Crosse virus)

[Results in a mild encephalitis, sometimes only meningitis]
RNA Viruses:

Causes pleurodynia (Bornholm disease)
Coxsackie B virus

[Sudden onset of stabbing chest pain with waxing and waning symptoms]
RNA Viruses:

Most common cause of viral myocarditis
Coxsackie B Virus

[Usually self-limiting, but may cause fatal arrhythmias or lead to dilated cardiomyopathy]
RNA Viruses:

Causes herpangina
Coxsakievirus

[Discrete vesicles on the throat and tongue with pain and difficulty swallowing]
RNA Viruses:

Infection may result in destruction of the pancreas with resultant insulin-dependent diabetes mellitus
Coxsackieviruses B3 and B4

[May be due to molecular mimicry owing to shared antigens between virus and pancreatic beta cells]
RNA Viruses:

Causes a severe hemorrhagic fever with outbreaks in Zaire and Sudan
Ebola virus

[Another filovirus family member, Marburg virus, has been associated with infection of laboratory personnel working with monkey tissue]
RNA Viruses:

Infection leads to severe hemorrhage and renal failure
Hantavirus

[A member of the Bunyavirus family with three segments of RNA]
RNA Viruses:

Infection is associated with ingestion of raw shellfish from fecally contaminated water
Hepatitis A virus (HAV)

[The virus is transmitted via the fecal/oral route and causes an acute hepatitis with no chronic carrier state]
RNA Viruses:

Major cause of post-transfusion hepatitis
Hepatitis C virus (HCV)

[This Flavavirus often results initially in subclinical infection although it is a major cause of chronic hepatitis and cirrhosis in the United States; it is the hepatitis virus most likely to result in hepatocellular carcinoma]
RNA Viruses:

Replication-deficient virus, requiring the presence of hepatitis B virus for productive infection
Hepatitis D virus (HDV)

[The HDV viral particle, known as the Dane particle, requires packaging into hepatitis B surface antigen to be infectious]
RNA Viruses:

Infection is associated with a high mortality rate in infected pregnant women
Hepatitis E virus (HEV)

[This Calcivirus is transmitted by the fecal/oral route, as with hepatitis A, and is most prevalent in developing nations]
RNA Viruses:

Infection leads to destruction of T cells, with the development of life-threatening opportutnistic infections
Human immunodeficiency virus (HIV)

[Opportunistic infections include CMV infection, Kaposi sarcoma, Pneumocystis carinii, Toxoplasma gondii, and Mycobacterium avium-intracellulare]
RNA Viruses:

Virus binds to CD4+ cells via viral glycorotein gp120
Human immunodeficiency virus (HIV)

[Entry of virus requires the presence of chemokine receptors CCR5 on monocyte/macrophages or CXCR4 on T lymphocytes]
RNA Viruses:

Retrovirus that causes oncogenic transformation of CD4+ T cells
Human T-cell lymphotropic virus-1 (HTLV-1)

[This virus, related to HIV, is endemic to Japan and the Caribbean basin, and also causes Tropical spastic paraparesis]
RNA Viruses:

Treatment with salicylates for this viral cause of respiratory symptoms may result in Reye syndrome in children
Influenza virus (Orthomyxovirus)

[In children, this virus can also cause croup, otitis media, muscle aches, and a high fever; influenza and retroviruses are the only RNA viruses to replicate in the nucleus]
RNA Viruses:

Changes in the viral surface proteins resulting from point mutations; reassortment of genome segments result in epidemics and pandemics
Influenza virus (orthomyxovirus)

[Point mutations in viral hemagglutinin (HA) or neuraminidase (NA) result in antigen drift, whereas reassortment of genes results in antigenic shifts]
RNA Viruses:

Major viral cause of pneumonia, and infection typically predisposes to secondary bacterial pneumonia
Influenza virus (orthomyyxovirus)

[Decrease in respiratory mucosal viscosity by viral neuraminidase and destruction of the respiratory epithelium lower the resistance to bacterial superinfection by Staphylococcus spp., Streptococcus spp., and Haemophilus spp. infection]
RNA Viruses:

Infection has been associated with subacute sclerosing panencephalitis (SSPE)
Measles virus

[Caused by a defective virus encoding a defective M protein]
RNA Viruses:

Infection leads to an immune-mediated maculopapular rash on the head, trunk, and limbs
Measles virus

[The presence of Koplik spots, small bluish-white ulcerations on the oral mucosa, are pathognomonic]
RNA Viruses:

Giant-cell pneumonia and encephalomyelitis are potential complications
Measles virus

[Vaccination for this previously common viral infection is included in the MMR vaccine, along with mumps and rubella]
RNA Viruses:

Infection can result in orchitis, which can lead to sterility
Mumps virus

[Orchitis complicates parotidits in 20% of infected males]
RNA Viruses:

Infection results in swelling of one or both parotids
Mumps virus

[May result in aseptic meningitis and pancreatitis]
RNA Viruses:

Major agent of epidemic gastroenteritis in adults
Norwalk agent

[Outbreaks of this Calcivirus are common in institutional settings and on cruise ships]
RNA Viruses:

Leading cause of croup
Parainfluenza virus

[Also known as laryngotracheobronchitis, obstruction of the larynx results in a characteristic seal-bark cough]
RNA Viruses:

Infection leads to the destruction of the cells of the anterior horn of the spinal cord
Poliovirus

[Viral infection with this picornavirus can lead to denervation atrophy of innervated muscles with flaccid paralysis]
RNA Viruses:

Infection is associated with an aversion to water, foaming at the mouth, and choking (hydrophobia)
Rabies virus

["Bullet-shaped" virion can be seen by electron microscopy; causes intracellular viral inclusions in infected cells known as Negri bodies]
RNA Viruses:

Only virus for which postexposure vaccination is indicated
Rabies virus

[Long incubation period allows for the development of a protective immune response, without which CNS symptoms lead invariably to death]
RNA Viruses:

Infection is associated with symptoms of sympathetic over-reactivity (i.e.salivation)
Rabies virus

[Virus binds to the nicotinic acetylcholine receptor]
RNA Viruses:

Most important cause of lower respiratory tract infection in infants
Respiratory syncytial virus (RSV)

[Virally infected cells often form multinucleated syncytia]
RNA Viruses:

Virion contains two identical strands of positive RNA (diploid-like genome)
Retrovirus

[The virion also carries and RNA-dependent RNA polymerase, a reverse transcriptase, and an integrase for integration into the host cell genome]
RNA Viruses:

Major cause of upper respiratory tract infections in humans
Rhinovirus

[This picornavirus binds and enters epithelial cells via attachment to ICAM-1 and replicates best at 33⁰C, explaining its predilection for the mucosa of the nasopharynx]
RNA Viruses:

Major cause of diarrhea (gastroenteritis) in young children
Rotavirus

[This reovirus contains 10-12 segments of dsRNA within two concentric capsids]
RNA Viruses:

Teratogenic virus leading to congenital defects of the heart, brain, and eye
Rubella virus

[A member of the TORCH group of infectious agents that are capable of crossing the placenta and infecting the developing fetus]
RNA Viruses:

This cause of mosquito-borne encephalitis can also be transmitted via blood transfusions and organ transplants, and causes life-threatening symptoms in elderly and immunosuppressed patients
West Nile Virus

[Although first reported in Africa in the 1930's, the appearance of the Flavivirus family was first reported in the United States in 1999; recent years have seen large outbreaks with thousands of cases and nearly 200 deaths]
RNA Viruses:

Arbovirus that causes severe hepatitis with jaundice and severe gastrointestinal hemorrhage with black vomit
Yellow fever virus

[Infection by this Flavivirus, transmitted by the Aedes mosquito, can be prevented using a vaccine developed from the 17D strain]
Disease:

A unique class of infectious agents that can result in Spongiform encephalitis
Prions

[Composed only of proteinaceous material, it is highly resistant to most forms of sterilization and can be transmitted iatrogenically (e.g. surgical instruments, cadaveric material), or from consuming contaminated meats]
Disease:

Opportunistic infections common in AIDS patients:

✦ Bacterial?

✦ Fungal?

✦ Protozoal?

✦ Viral?
✦ Bacterial: Mycobacterium avium-intracellulare

✦ Fungal: Pneumocystis carinii

✦ Protozoal: Toxoplasma gondii & Cryptosporidium parvum

✦ Viral: Cytomegalovirus (CMV) & Kaposi sarcoma virus
Disease:

Major sexually transmitted diseases in the United States:

✦ Bacterial?

✦ Protozoal?

✦ Viral?
✦ Bacterial: Chlamydia trachomatis & Neisseria gonorrhoeae

✦ Protozoal: Trichomonas vaginalis

✦ Viral: Herpes simplex virus-2 (HSV-2), Human Immunodeficiency virus (HIV) & Human papilloma virus (HPV)
Disease:

Major causes of meningitis:

✦ Newborns?

✦ Children?

✦ Young adults?

✦ Elderly (>60 years)?

✦ AIDS patients?
✦ Newborns: Streptococcus agalactiae & Escherichia coli

✦ Children: Haemophilus influenzae

✦ Young adults: Neisseria meningitidis

✦ Elderly: Streptococcus pneumonia

✦ AIDS patients: Cryptococcus neoformans
Disease:

Major cause of pneumonia:

✦ Neonates?

✦ Children (6 weeks-18 years)?

✦ Adults?

✦ Elderly (60 years)?

✦ Alcoholics & IV drug users?

✦ Post-viral?

✦ Cystic fibrosis patients?
✦ Neonates: Streptococcus agalactiae & Escherichia coli

✦ Children: Respiratory syncytial virus (RSV) & Streptococcus pneumoniae (<4 years)

✦ Adults: Mycoplasma pneumonia

✦ Elderly: Streptococcus pneumoniae

✦ Alcoholics & IV drug users: Klebsiella pneumonia

✦ Post-viral: Haemophilus influenza

✦ Cystic fibrosis patients: Pseudomonas aeruginosa
Disease:

Common nosocomial infections associated with:

✦ Newborns?

✦ Urinary catheterizations?

✦ Renal dialysis units?

✦ Respiratory therapy equipment?

✦ Water aerosols?
✦ Newborns: Respiratory syncytial virus (RSV) & Cytomegalovirus (CMV)

✦ Urinary catheterizations: Escherichia coli & Proteus spp.

✦ Renal dialysis units: Hepatitis B virus (HBV)

✦ Respiratory therapy equipment: Pseudomonas aeruginosa

✦ Water aerosols: Legionella pneumophila
Disease:

Major causes of endocarditis:

✦ Subacute endocarditis?

✦ Acute endocarditis?

✦ IV drug users?

✦ Patients with prosthetic valves?
✦ Subacute endocarditis: Streptococcus viridans

✦ Acute endocarditis: Staphylococcus aureus

✦ IV drug users: Staphylococcus aureus

✦ Patients with prosthetic valves: Staphylococcus epidermidis
Disease:

Major causes of osteomyelitis:

✦ General population?

✦ Sexually active?

✦ Drug users?

✦ Sickle cell anemia patients?
✦ General population: Staphylococcus aureus

✦ Sexually active: Neisseria meningitidis

✦ Drug users: Pseudomonas aeruginosa

✦ Sickle cell anemia patients: Salmonella spp.
Disease:

Organisms causing a watery diarrhea
Cryptosporidium parvum
Escherichia coli
Vibrio cholerae
Giardia lamblia
Norwalk Agent
Rotavirus
Disease:

Major causes of urinary tract infections
Escherichia coli (most common)
Enterococcus faecalis
Klebsiella pneumonia
Proteus mirabilis
Proteus vulgaris
Pseudomonas aeruginosa
Serratia marcescens
Staphylococcus saprophyticus
Disease:

Organisms causing a bloody diarrhea (dysentery)
Campylobacter jejuni
Escherichia coli (enteroinvasive and enterohemorrhagic)
Salmonella spp.
Shigella dysenteriae
Entamoeba histolytica
Disease:

Major causes of food poisoning
Bacillus cereus
Clostridium perfringens
Staphylococcus aureus
Vibrio parahaemolyticus
Disease:

Major cause of transplacental neonatal infections
Toxoplasma gondii
Treponema pallidum
Rubella virus
Cytomegalovirus (CMV)
Herpes simplex virus (HSV)
Human immunodeficiency virus (HIV)

[Collectively known as the TORCH group, many of these infections can lead to congenital defects if acquired in utero]
Disease:

Major causes of transcervical neonatal infections (acquired by vaginal delivery)
Candida albicans
Escherichia coli
Listeria monocytogenes
Streptococcus agalactiae