03 - Special Culture or Exam Required - Microbes 31 through 36

Question 1

Name all of the Microbe Genera that require a special culture or exam?

Also think of the special exam or culture

Some have been described in further detail earlier…

Answer 1

Mycobacterium (Acid-fas stain, PCR, special culture)

Chlamydia (ELISA, PCR)

Mycoplasma (ELISA / EIA or special culture)

Legionella (immunodiagnostic)

Rickettsia (immunodiagnostic)

Coxiella (ELISA, PCR)

Borrelia

Treponema (immunodiagnostics, IF immu-fluoroescence microscopy (DARKFIELD)) (NOT COVERED IN MICROBES PDF)

Leptospira (NOT COVERED IN MICROBES PDF)

Trichomonoas (protozoa, wet prep, microscopy) **(NOT COVERED IN MICROBES PDF)

Question 2

a. Very small, unusual, atypical gram-negative bacteria (not realistic to observe via Gram stain); obligate intracellular
b. Obligate intracellular parasite
(1) Elementary Bodies (EB) – infectious form; metabolically inactive; moderately resistant to harsh environment; convert into RB
(2) Reticulate Bodies (RB) – noninfectious; metabolically active;

Answer 2

Chlamydia trachomatis

Question 3

c. Cell structures
(1) Lipopolysaccharide – only weak endotoxin activity
(2) Major Outer Membrane Protein (MOMP) – the important structural component of cell wall

d. Reproduction:
(1) EB enters host cell
(2) EB converts to RB (inclusions)
(3) RB replicates bacterial cells and produce EB

Answer 3

Chlamydia trachomatis

Question 4

Leading cause of STD’s

Answer 4

Chlamydia trachomatis

Question 5

STD - leading cause (50% of cases) – may be referred to as “non-gonococcal urethritis”

Answer 5

Chlamydia trachomatis

Question 6

“non-gonococcal urethritis”

Answer 6

Chlamydia trachomatis

Question 7

(1) Sexually Transmitted Disease
(2) Trachoma - Inclusion conjunctivitis disease – a leading cause of blindness
(3) Lymphogranuloma venereum – involvement of inguinal lymph nodes

Answer 7

Chlamydia trachomatis

Question 8

Trachoma - Inclusion conjunctivitis disease – a leading cause of blindness

Answer 8

Chlamydia trachomatis

Question 9

Typical treatment of Chlamydia trachomatis

Answer 9

(e.g. doxycycline, tetracycline, or erythromycin) intended to cover gonorrhea also

Question 10

Lab Dx of Chlamydia trachomatis

Answer 10

Laboratory diagnosis
(1) Obligate intracellular parasite -- requires a living host cell for culture

(2) Clinical diagnosis may be based on the failure to demonstrate Neisseria gonorrhoeae by smear or culture
(3) Special culture materials required – collection kit includes cell culture vial
(4) Identify by using nucleic acid probe or ELISA

Question 11

a. Agent of pneumonias, bronchitis, sinusitis – usually asymptomatic or mild with persistent cough
b. Probable agent of atherosclerosis – inflammation of endothelium of blood vessels which then leads to plaque buildup

Answer 11

Chlamydia pneumoniae

Question 12

a. Atypical bacterium – no cell wall, small, poorly staining
b. Etiological agent of “primary atypical pneumonia” (walking pneumonia)

Answer 12

Mycoplasma pneumoniae

Question 13

walking pneumonia

Answer 13

Mycoplasma pneumoniae

Question 14

(1) Symptoms (after 1-3 weeks incubation): headache, malaise, cough (often paroxysmal), and less often chest discomfort
(2) Sputum production may be scant; infiltration of lungs may be more extensive than clinical findings suggest
(3) Pneumonia may progress from one lobe to another and may be bilateral (“walking pneumonia”)
(4) Duration of illness: often more than a month
(5) Epidemiology – occurs primarily in school age children and young adults, especially military (up to 50/1,000/year)
(6) Treatment: Erythromycin or tetracycline

Answer 14

Etiological agent of “primary atypical pneumonia” (walking pneumonia) WHICH IS

Mycoplasma pneumoniae

Question 15

Pneumonia may progress from one lobe to another and may be bilateral

Answer 15

walking pneumonia found in Mycoplasma pneumoniae

Question 16

Laboratory diagnosis – Requires special request and special culture media and complex tests – procedures are generally not available except in the most sophisticated of labs

For this type of pnemonia Lab Dx described above

Answer 16

Mycoplasma pneumoniae

Question 17

a. “Atypical” bacteria – small, coccobacilli, obligate intracellular parasites
b. Various species cause spotted fever or typhus
(1) Spotted Fever
(a) Rocky Mountain Spotted Fever – Tick (R. rickettsii)
(2) Typhus
(a) Epidemic typhus (classical typhus fever) – Louse (R. prowazekii)
(b) Murine typhus – Flea (R. typhi)
(c) Scrub typhus – Mite (Orientia tsutsugamushi)

Answer 17

Rickettsia and Orientia species

Question 18

when you hear TICK think….

Answer 18

Rickettsia and Orientia species

Question 19

Spotted Fever &/or Typhus think…

Answer 19

Rickettsia and Orientia species

Question 20

Rocky Mountain Spotted Fever – Tick

Answer 20

(R. rickettsii)

Question 21

Epidemic typhus (classical typhus fever) – Louse

Answer 21

(R. prowazekii)

Question 22

Murine typhus – Flea

Answer 22

(R. typhi)

Question 23

Scrub typhus – Mite

Answer 23

(Orientia tsutsugamushi)

Question 24

what are generally effective antimicrobics for

Answer 24

Tetracyclines and chloramphenicol

Question 25

Laboratory diagnosis
(1) Immunologic test of serum or PCR

(2) Cultured only in reference laboratories using living host cells and adequate containment – whole blood or biopsied tissue may be cultured

Answer 25

Rickettsia and Orientia species

Question 26

c. Clinical manifestations: abrupt onset (usually), fever (2-3 weeks), headache, severe deep muscle pain, and rash (no eschar from primary pathogens) (location not at site of entry)
d. Mortality rate: 3% to 5% in treated cases; 10% to 25% in untreated cases
e. Transmitted by tick, mite, body louse, flea (species specific)

Answer 26

Rickettsia and Orientia species

Question 27

a. “Atypical” bacteria – small, coccobacilli, gram-negative but does not stain well
b. Obligate intracellular parasites with multi-stage developmental lifecycle
c. Biological threat agent

Answer 27

Coxiella burnetti

NOT

Rickettsia and Orientitia because R/O do are not considered gram-negative like Coxiella

Question 28

obligate intracellular parasite + Biological threat agent =

Answer 28

Coxiella burnetti

OR

Epidemic typhus (classical typush fever) R. Prowazekii

Question 29

Etiologic Agent of Q Fever

Answer 29

Coxiella burnetti

Question 30

(1) Disease of numerous animals, especially sheep, goats, cattle
(2) Highly infectious/communicable via body fluids and aerosol to other animals and humans
(3) Symptoms – high fever, headache, myalgias, arthralgias, cough, and involves multiple organs

Answer 30

Coxiella burnetti

Question 31

Diagnosed by immunologic and nucleic acid tests (parasitic in nature)

Answer 31

Coxiella burnetti

Question 32

Acid-fast bacilli – large amounts of mycolic acids and lipids in cell wall impairs staining with aqueous stains

Answer 32

Mycobacterium tuberculosis

Question 33

Laboratory diagnosis (all species of Mycobacterium)

Answer 33

(1) Microscopic exam – acid-fast stain or fluorochrome stain (more sensitive)
(2) Identification
(a) Traditional method requires special culture — 4-6 weeks initial culture plus 2 weeks for susceptibility testing using Lowenstein-Jensen or Middlebrook media
(b) Newer methods – 1-2 weeks initial culture plus 1 week for susceptibility testing using Bactec radiometric media & instrument
(c) Newest methods – Nucleic acid probe identification