POORLY STAINING

Question 1

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

Answer 1

Chlamydia trachomatis

-infection in a female can progress to PID, resulting in potential for ECTOPIC PREGNANCY or STERILITY

Question 2

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

Answer 2

Chalmydia trachomatis

-this AUTOIMMUNE phenomeno resulting from cross-reactive antigens between the organism and affected tissues is associated with HLA-B27

Question 3

One of the most common opportunistic bacterial infections in AIDS patients

Answer 3

Mycobacterium avium-intracellulare

-this disease presents similarly to TB and is acquired from soil, birds, or other animals

Question 4

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

Answer 4

Mycobacterium leprae

-leprosy, or HANSEN DISEASE, presents as a spectrum between 2 extremes, from TB LEPROSY associated with good prognosis to LEPROMATOUS LEPROSY, in which numerous acid-fast bacilli are stuffed in macrophages = LEPRA CELLS

Question 5

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

Answer 5

Mycobacterium leprae

-this acid-fast bacilli has a LONG GENERATION TIME, approximately 13 days, and cannot be cultivated in the laboratory

Question 6

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

Answer 6

Mycobacterium tuberculosis

-diagnosis is confirmed by finding ACID-FAST BACILLI in the sputum or in cultures that take several weeks to grow

Question 7

The classic presentation with this organism includes fever, night sweats, fatigue, and weight loss

Answer 7

Mycobacterium tuberculosis

-presents similarly to other GRANULOMATOUS INFECTIONS such as histoplasmosis or coccidiodomycosis

Question 8

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

Answer 8

Mycobacterium tuberculosis

-although rare in the US, incidences of infections are INCREASING IN IMMUNOCOMPROMISED pts and urban populations, with high incidence of MULTIDRUG-RESITANT STRAINS

Question 9

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

Answer 9

Treponema pallidum

-the characteristic lesion of primary syphilis is HIGHLY CONTAGIOUS and contains numerous SPIROCHETE viewed by DARK FIELD light microscopy or by IMMUNOFLUORESCENT MICROSCOPY

Question 10

The disease can manifest with a maculopapular rash on the palsm and soles, and condyloma lata

Answer 10

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

Question 11

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

Answer 11

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

Question 12

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

Answer 12

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 US

Question 13

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

Answer 13

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

Question 14

This cause of chronic keratoconjunctivitis results in corneal scarring and is the most common cause of blindness worldwide

Answer 14

Chlamydia trachomatis

-Chlamydia trachomatis is divided into SEROVARS based on serology and symptomatology; in this case, the pathology is due to C. trachomatis A, B, and C

Question 15

Causes Lymphogranuloa venerum, characterized by nodules and vesicles on the genitals, venereal buboes, and elephantiasis of the genitals with rectal strictures

Answer 15

Chlamydia trachomatis

-results from infection of the most invasive SEROVARS L1, L2, and L#; this STD progresses through primary, secondary, and tertiary stages

Question 16

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

Answer 16

Legionella pneumophila

-this organism, often visualized with DIETERLE SILVER STAIN, also causes a less severe form of pneumonia known as PONTIAC FEVER

Question 17

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

Answer 17

Mycobacterium tuberculosis

-the test for exposure to TB involve injection of a small amount of partially purified derivative [PPD] and detecting a DELAYED TYPE HYPERSENSITIVITY rxn; recipients of the vaccine [an ATTENUATED STRAIN OF M. bovis] have a positive PPD

Question 18

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

Answer 18

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

Question 19

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

Answer 19

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

Question 20

Causes “Walking pneumonia” with the potential to develop a self-limiting hemolytic anemia

Answer 20

Mycoplasma pneumoniae

-untreated pts develop IgM AUTOANTIBODIES TO RBC’s, terms ACUTE COLD AGGLUTININS

Question 21

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

Answer 21

Mycoplasma pneumoniae

-one of the SMALLEST FREE-LIVING BACTERIA, has NO CELL WALL, and causes an INTERSTITIAL INFLAMMATION rather than intra-alveolar exudates

Question 22

This organism that lacks a cell wall is the cause of recurrent UTIs

Answer 22

Ureaplasma urealyticum

-related to Mycoplasma pneumonia, infection is associated with the development of URINARY CALCULI

Question 23

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

Answer 23

Borrelia burgdorferi

-the vaccine has recently become available for this organism, to prevent development of LYME DISEASE

Question 24

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

Answer 24

Treponema pallidum

-infection results in OSTEOCHONDRITIS and PERISOTITIS and contributing as well to other defects such as DESTRUCTION OF THE VOMER, leading to a SADDLE NOSE DEFORMITY; other bone defects include mulberry molars and saber shin deformities

Question 25

Transmitted by the human body louse, this organism causes Relapsing fever

Answer 25

Borrelia recurrentis

-causes a FEBRILE DISEASE that fades as antibodies develop and RELAPSES as the organism undergoes ANTIGENIC VARIATION of its variable major protein

Question 26

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

Answer 26

Rickettsia prowazekii

-characterized by extreme fever, myalgias, and a rash; a less severe form of the disease, ENDEMIC TYPHUS, results from Rickettsia typhi

Question 27

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

Answer 27

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 classic serologic test for Rickettsia, the WEIL-FELIX TEST

Question 28

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

Answer 28

Chlamydia pneumoniae

-as with all Chlamydia species, it exists as either ELEMENTARY BODIES, the infectious form, or as INTRACELLULAR RETICULAR BODIES, the metabolically active form

Question 29

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

Answer 29

Borrelia burgdorferi

-infection occurs mainly in the NE during the SUMMER months, when the deer tick [Ixodes] is found