L9- Atypical Bacteria

Question 1

define insidious

Answer 1

slow growing (weeks - months), often resistant to first line antibiotics

Question 2

(1) and (2) are important Actinomycetes and share these two important features: (3) and (4)

Answer 2

1- Actinomyces
2- Nocardia
3- long, branching filaments
4- Gram+ wall

Question 3

Actinomyces israelii are (aerobic/anaerobic) that are (endo/exo)-genous to to the body. They most notably result in (3- include its unique characteristics), but can also result in (4)

Answer 3

1- anaerobic
2- endogenous (commensal oral and GI flora)
3- opportunistic abscesses in anoxic tissue (Lumpy Jaw) with sulfur/foul smelling granules
4- slow granulomatous abscessed in any tissue

Question 4

define acid-fast test and what a positive result indicates

Answer 4

• heat fix to slide –> de-stain with Acid Alcohol

- bacteria with Thick Lipid Mycolic Acid Wall retain the stain –> appear Red

Question 5

acid-fast stain is also called….

Answer 5

Ziehl-Neelsen stain

Question 6

what are the two types of Acid-Fast bacteria

Answer 6

• Nocardia, acid fast branching

- Mycobacterium species, acid fast bacilli

Question 7

list features of Nocardia asteroides

Answer 7

• acid-fast branching filamentous
• weakly Gram+
• aerobic
• exogenous transmission: inhalation of dust

Question 8

Nocardia asteroides infection is called (1) and will result in (2) in the (3) part of the body, particularly in (4) patients

Answer 8

1- nocardiosis
2- opportunistic abscesses (pulmonary cavitation disease)
3- lungs
4- immuno-comprimised

Question 9

describe the mechanism of mycobacterium tuberculosis (TB) infection

Answer 9

• a facultative intracellular organism
• transmission through air droplets (via active pulmonary disease)
• organism is phagocytized, but unable to be digested due to thick lipid cell wall
• granulomas formed and host tissue damage due to inc in CKs and recruitment proteins

Question 10

Mycobacterium tuberculosis takes advantage of individuals with….

Answer 10

low cell-mediated immunity (CD4+ Th1)

-ex. young children

Question 11

Mycobacterium leprae (leprosy) is a (obligate/facultative) intracellular bacteria that replicates in (2) or (3). It is spread through (4).

Answer 11

1- obligate intracellular bacteria
2- macrophages
3- nerve cells
4- close contact with untreated leper over many months

Question 12

what two diseases are caused by mycobacterium leprae

Answer 12

• both involve nerves and cause loss of sensation, difference is based on host immune response
  1) Lepromatous leprosy- more severe
  2) Tuberculoid Leprosy- less severe

Question 13

Mycobacterium marinum are infections of the (1) from contact through (2) via (3). The first signs of infection are (4)

Answer 13

1- skin
2- aquariums, fish (in fresh or saltwater)
3- skin exposure (cut, scrape)
4- reddish, tan skin with granuloma

Question 14

list some features of Mycoplasma ssp and include some examples of species

Answer 14

• no cell wall
• smallest prokaryote
• sterols in membrane
• ‘fried egg’ appearance on Histo.

Exs: Mycoplasma pneumoniae or genitalium, Ureaplasma

Question 15

Mycoplasma pneumoniae is also called (1) and is transmitted via (2). They are resistance to (3) due to the lack of cell wall and usually present as (4).

Answer 15

1- walking or atypical pneumonia
2- air droplets
3- 1st line anti-biotics (β-lactams, cephalosporins)
4- dry persistent cough

Question 16

Mycoplasma genitalium and Ureaplasma are STIs that cause (1) in females with (2) and (3) as symptoms and (4) and (5) as possible long term complications

Answer 16

1- PID (pelvic inflammatory disease)
2- painful intercourse
3- vaginal bleeding/discharge
4- sterility
5- ectopic pregnancy
(complications due to being a long, asymptomatic infection)

Question 17

Mycoplasma genitalium and Ureaplasma are STIs that cause (1) in males with (2) and (3) as symptoms and (4) as a possible long term complication

Answer 17

1- urethritis
2- stinging/burning during urination
3- penile discharge
4- sterility
(complications due to being a long, asymptomatic infection)

Question 18

what is a special feature of Ureaplasma in pregnant females

Answer 18

it can cross the placenta –> spontaneous abortion or pre-mature birth

Question 19

Chlamydia species are (obligate/facultative) intracellular bacteria meaning they depend on (2) and (3) from the host. They are Gram(+/-). (5) is required for growth in lab.

Answer 19

1- obligate intracellular bacteria
2- ATP
3- NAD
4- neither, don't Gram stain well
5- tissue culture, can't grow on plate/agar

Question 20

Chlamydia exists in (1) or (2) form

Answer 20

1- EB, elementary body / infectious form

2- RB, reticulate body / replicative form

Question 21

list the Chlamydia species

Answer 21

• Chlamydia trachomatis (STI, trachoma)
• Chlamydia pneumoniae (pneumonia)
• Chlamydia psittaci (Psittacosi- zoonotic disease)

Question 22

briefly describe the cycle of Chlamydia species

Answer 22

1) EB invades epithelial cell as inclusion body
2) EB –> RB w/in cell
3) RB multiplies
4) RB condense to EB form
5) EB form matures
6) EB is released to infect other cells

Question 23

describe structure of Acid-Fast Mycolic Cell Wall

Answer 23

• Mycolic acids –> thick lipid waxy layer –> limits nutrient uptake => slow growth rate & adds additional protection (no lysosomal fusion w/in macrophage)
• Waxy coat interferes with Gram staining
• Cord Factor (glycolipid) is present –> toxic by disrupting oxidative phosphorylation

Question 24

(1) is a glycolipid found on Acid-Fast Mycolic Cell Walls and is very toxic, involved in (2)

Answer 24

1- Cord factor

2- disrupting oxidative phosphorylation

Question 25

indicate which disease each Chlamydia trachomatis serotype causes:

(1) A, B, C
(2) D - K
(3) L1-L3

Answer 25

1- trachoma
2- urogenital infections (STIs)
3- Lymphogranuloma Venereum (LVG- uncommon STI)

Question 26

what is a trachoma

Answer 26

blinding ocular disease caused by Chlamydia trachomatis (serotype A, B, C), usually in developing countries

Question 27

(1)% of Chlamydia trachomatis Cervicitis is asymptomatic and if left untreated can lead to the following (2- hint 4 things). The best screening is (3)

Answer 27

1- 80%
2- transmission to neonate, pelvic inflammatory disease, ectopic pregnancy, sterility
3- PAP smear- look for intracytoplasmic vacuoles

Question 28

serotype D-K Chlamydia cause (1) or (2) in males, (3)% are asymptomatic

Answer 28

1- nongonoccal urethritis (if w/o gonorrhea which it is commonly transmitted with)
2- epididymitis
3- 50%

Question 29

serotype D-K Chlamydia cause (1) and (2) in everyone and (3) and (4) in neonates

Answer 29

1- inclusion conjunctivitis
2- proctitis (rectal infection)

3- inclusion conjunctivitis
4- infant pneumonia

Question 30

these two types of Chlamydia species cause atypical pneumonia, but include differences in transmission

Answer 30

• Chlamydia pneumonia via human to human aerosals
• Chlamydia psittaci via exposure to birds (Zoonotic / ‘Parrot fever’)
• Both have persistent cough for wks to mos, whether in teenagers or exposed zoo workers

Question 31

list the three types of Rickettsia and their associated arthopod

Answer 31

• R. rickettsi via Ticks
• R. prowazekii via Lice
• R. typhi via Fleas

Question 32

Rickettsia bacteria are (obligate/facultative) intracellular bacteria and are transmitted via (2). They usually penetrate skin or mucous membranes to infect (3)

Answer 32

1- obligate intracellular bacteria
2- arthropods
3- endothelial cells –> small BVs => vasculitis

Question 33

describe Rocky Mountain Spotted Fever

Answer 33

• from tick bite infected with Rickettsia rickettsii, onset is 7-14 days afterwards
• high fever, regional lymphadenopathy
• endovasculitis => petechial rash (spotted rash) on palms/soles, encephalitic signs, gangrene of skin/tissues