Legionella

Question 1

Ubiquitous gram-negative bacilli
and acquired through inhalation.

Answer 1

Legionella

Question 2

Laboratory diagnosis for Legionella except:
A. Isolation using special media
B. Urine antigen detection
C. Direct fluorescent antibody
D. PCR
E. Serology

Answer 2

D

Question 3

The most common pathogen of Legionella.

Answer 3

Legionella pneumophila

Question 4

They have the ability to enter, survive, and multiply within host’s
cells,

Answer 4

Legionella / L. pneumophila

Question 5

Most Legionella invades what macrophage?

Answer 5

bronchoalveolar macrophages

Question 6

Legionella has the ability to produce ___.

Answer 6

proteolytic enzymes

Question 7

T or F
Legionella spp. cause intracellular infections in humans but also survive in an extracellular environment.

Answer 7

True

Question 8

Legionella can cause all the infections except:
A. BPF
B. Legionnaire’s Disease
C. Pontiac Fever
D. Asymptomatic Infection

Answer 8

A

Question 9

Febrile disease with pneumonia brought by Legionella.

Answer 9

Legionnaire’s Disease

Question 10

Febrile disease without pulmonary caused by Legionella

Answer 10

Pontiac Fever

Question 11

Three major patterns of Legionnaire’s Disease.

Answer 11

1. Sporadic
2. Epidemic
3. Nosocomial

Question 12

Most common patterns of Legionnaire’s Disease and spread in comunity.

Answer 12

Sporadic

Question 13

Short duration pattern of Legionnaire’s disease and has low attack rates

Answer 13

Epidemic

Question 14

patterns of Legionnaire’s Disease in immunocompromised

Answer 14

Nosocomial

Question 15

Caused by L. pneumophila that can be pneumonia (atypical).

Answer 15

Legionnaire’s Disease

Question 16

A nonpneumonic form, short incubation period (2 days), Flulike symptoms caused by L. pneumophila

Answer 16

Pontiac fever

Question 17

It occurs naturally in aquatic sources (lakes, rivers,
hot springs, mud)

Answer 17

Legionella

Question 18

T or F
Legionella can tolerate chlorine (resists water treatment)

Answer 18

True

Question 19

Major reservoir of Legionella.

Answer 19

• Hot water systems
• cooling towers
• evaporative condensers

Question 20

Laboratory Diagnosis for Legionnaire’s disease.

Answer 20

Urine antigen detection + culture

Question 21

Lab. diagnosis for pontiac fever.

Answer 21

Serology

Question 22

Specimens for Legionella

Answer 22

– Sputum
– Bronchoalveolar lavage
– Bronchial washings

Question 23

Why saline or buffer should not be used in isolation of Legionella? (inhibitory effect
of sodium)

Answer 23

It has an inhibitory effect of sodium

Question 24

How many hours req. To refrigerate the specimens of Legionella for transportation

Answer 24

2 hours

Question 25

Characteristics of Legionella under microscope.

Answer 25

Pleomorphic, weakly staining, gram-negative bacilli.

Question 26

Since the Legionella is weakly stained in safranin, how many mins. Need to stain the organisms properly?

Answer 26

10 mins. For better absorption.

Question 27

weakly acid-fast; stains best with modified Kinyoun procedure.

Answer 27

L. micdadei

Question 28

Confirmation test for Legionella.

Answer 28

DFA TEST (Direct Fluorescent Antibody Test)

Question 29

Common dye for DFA Test.

Answer 29

FITC (Fluorescein isothiocyanate) yellow green color

Question 30

Most important test for Legionnaire’s disease is __.

Answer 30

Culture

Question 31

_____ of specimens contaminated with other bacteria, such as sputum, before inoculation enhances isolation of Legionella spp.

Answer 31

Acid treatment

Question 32

Medium for Legionella spp. Requires ____ for growth.

Answer 32

L-cysteine

Question 33

Best medium for Legionella spp.

Answer 33

BCYE agar with L-cysteine

Question 34

True or false Legionella is aerobic, fastidous, and does not grow in SBA.

Answer 34

True

Question 35

Appearance of Legionella spp. in BCYE.

Answer 35

- Grayish-white or blue-green, - convex - glistening

Question 36

The central portion of young Legionella colonies has a _____ appearance, and the color is ___.

Answer 36

groundglass appearance”, light gray and granular

Question 37

Color of periphery of Legionella colonies.

Answer 37

- pink - light blue - bottle green (bands with a furrowed appearance)

Question 38

All are common Phenotypic Characteristics of Legionella Species except: A. Slow growth (3 to 5 days) B. Catalase or oxidase: weakly (-) C. ground-glass” colony morphology D. Asaccharolytic

Answer 38

B.Catalase or oxidase: weakly (+)

Question 39

Urine Antigen test for Legionella.

Answer 39

- RIA - EIA, - Immunochromographic assay

Question 40

___ test: LRT specimen; FITC-labeled (bright yellow to green)

Answer 40

DFA test

Question 41

3 rapid methods for identifying Legionella.

Answer 41

- Urine Antigen test: - DFA test - DNA detection