B4.1 MYCOBACTERIA Flashcards
MAJOR GENERA AND SPECIES TO BE CONSIDERED
I. Mycobacterium tuberculosis Complex
II. Nontuberculous Mycobacteria
I. Mycobacterium tuberculosis Complex spp
✓ M. tuberculosis
✓ M. bovis
✓ M. bovis BCG
✓ M. africanum
✓ M. caprae
✓ M. canettii
✓ M. microti
✓M. pinnipedii
II. Nontuberculous Mycobacteria subgroups
A. Slow-Growing Nonphotochromogens
B. Photochromogens
C. Scotochromogens
D. Rapid-growing, potentially pathogenic
A. Slow-Growing Nonphotochromogens spp
✓ M. avium complex
✓ M. intracellulare
✓ M. celatum
✓ M. ulcerans
✓ M. gastri
✓ M. genavense
✓ M. haemophilum
✓ M. malmoense
✓ M. shimoidei
✓ M. xenopi
✓ M. heidelbergense
✓ M. branderi
✓ M. simiae
✓ M. triplex
✓ M. conspicuum
M avium complex
✓ M. avium
subsp. avium
subsp. silvaticum
subsp. paratuberculosis
B. Photochromogens spp.
✓ M. kansasii
✓ M. asiaticum
✓ M. marinum
C. Scotochromogens spp.
✓ M. szulgai
✓ M. scrofulaceum
✓ M. interjectum
✓ M. gordonae
✓ M. cookii
✓ M. hiberniae
✓ M. lentiflavum
✓ M. conspicuum
✓ M. heckeshornense
✓ M. tusciae
✓ M. kubicae
✓ M. ulcerans
✓ M. bobemicum
D. Rapid-growing, potentially pathogenic spp.
✓ M. fortuitum
✓ M. chelonae
✓ M. abscessus subsp. abscessus
✓ M. abscessus subsp. Bolletii
✓ M. smegmatis
✓ M. peregrinum
✓ M. immunogenum
✓ M. mucogenicum
✓ M. neworleansense
✓ M. brisbanense
✓ M. senegalense
✓ M. porcinum
✓ M. houstonense
✓ M. boenickei
✓ M. wolinskyi
✓ M. goodii
✓ M. septicum
✓ M. mageritense
✓ M. canariasense
✓ M. alvei
✓ M. novocastrense
✓ M. cosmeticum
✓ M. setense
✓ M. leprae
Non-cultivatable spp
✓ M. leprae
SPECIMEN COLLECTION AND TRANSPORT
* Recommend container
sterile, wide-mouth cup
with a lightly fitted lid
SPECIMEN COLLECTION AND TRANSPORT * Delayed longer than 1 hour transport method
refrigerated at 4°C
except blood
Respiratory specimens
✓ spontaneously expectorated sputum
✓ normal saline-nebulized induced sputum
✓ transtracheal aspirate
✓ bronchoalveolar lavage
✓ bronchoalveolar brushing
✓ laryngeal swab
✓ nasopharyngeal swab
Body fluids specimens
✓ pleural fluid
✓ pericardial fluid
✓ joint aspirate
✓ peritoneal fluid
✓ cerebrospinal fluid
✓ stool
✓ urine
✓ pus
Body tissues specimens
✓ blood
✓ bone marrow biopsy/aspirate
✓ solid organ
✓ lymph node
✓ bone
✓ skin
a. Sputum and Other Respiratory Secretions * Preferred specimen
Early-morning
specimen collected on 3 consecutive days
Sputum and Other Respiratory Secretions * Method of choice
Spontaneously produced sputum
Required volume for Sputum and Other Respiratory Secretions
5 to 10 ml
Type of sputum needed
->deep cough expectorated sputum or
aerosol of hypertonic saline induced
Microscopy results for Sputum and Other Respiratory Secretions to confirm a diagnosis
<10 SEC and >25 pus cells
from two of the first three sputum direct
smears (+)
Others Sputum specimens
Bronchial washing, bronchoalveolar lavage (BAL), or transbronchial biopsy-> Bronchoscopy
Specimen to recover mycobacteria swallowed during the night
Gastric Aspirates and Washings
Gastric Aspirates and Washings used for which patients
✓ patients who do not produce sputum
by aerosol induction
✓ children younger than 3 years->
specimen of choice
✓ senile, nonambulatory patients
- obtained in morning after an overnight
fast, before the patient arises and before
exertion empties the stomach
Gastric Aspirates and Washings
Gastric Aspirates and Washings collection method
- 3 specimens within 3 days
Used to neutraliz Gastric Aspirates and Washings specimen
sodium carbonate or buffer to PH 7.0
required volume for Gastric Aspirates and Washings
20 to 25 ml
Preferred specimen for Urine Specimens
First morning midstream specimens daily for at least 3 days
Volume required for urine specimens
entire volume or, minimum of 15 mL
Specimen used that identifies patients at risk for developing disseminated mycobacterial disease resulting from Mycobacterium avium complex (MAC) (AIDS)
- do not use preservative
- utilized in automated equipment
Stool
Stool automated equipment used
MGIT 960
Blood medium
MYCO/F bottle
Specimen used for
- disseminated mycobacterial infection-> MAC
✓ Isolator lysis-centrifugation system > quantitative data
Blood
Blood automated equipment used
✓ Bactec MGIT 960 system
- BacT/ALERT 3D or BacT/Alert MB
Specimen for tissue and other body fluids
Pleural, pericardial, peritoneal, joint aspirates and CSF
Volume Required for CSF
2 ml
Volume Required for exudates and pericardial and synovial fluids
3 to 5 ml -
Volume Required for abdominal and chest fluids
10 to 15 ml
Volume Required best type of specimen for skin lesion or wound
Aspirate
Volume Required to prevent dehydration
10 to 15 mL sterile NSS
Specimens that needs to undergo DIGESTION AND DECONTAMINATION
Sputum, gastric washing, BAL, bronchial washing, and transtracheal aspirate
Specimens that needs to undergo DECONTAMINATION
Voided urine, autopsy tissue, abdominal fluid,
and any contaminated fluid
- liquefy sample through digestion of
proteinaceous material (mucin)
-> enables mycobacteria to use
nutrients of the medium - allow chemical decontaminating agent to
kill the nonmycobacterial organisms
->concentrated with centrifugation
DIGESTION AND DECONTAMINATION OF
SPECIMENS
DIGESTION AND DECONTAMINATION OF
SPECIMENS Factors
concentration of the chemical agent, exposure time, and temperature
REAGENTS for Digestion and decontamination
main
2%-4% Sodium Hydroxide
N-Acetyl-L-cysteine-Sodium Hydroxide (NALCNaOH)
Benzalkonium Chloride (Zephiran)-Trisodium
Phosphate (Z-TSP)
5% Oxalic Acid
1% Cetylpyridium Chloride
REAGENTS for Digestion and decontamination
others
a. 4% H2SO4
b. Sputolysin (Dithiothreitol)-Oxalic Acid
c. 20% Chlorox
d. 1% Cetylpyridium Chloride + 2% NaCI
e. Sputolysin + 2% NaOH
f. 2 parts of Antiformin (Na Hypochlorite) to 1 part sputum
- digestant and decontaminating agent
- commonly used decontaminant (2ml sputum + 2ml NaOH)
2%-4% Sodium Hydroxide
*>recommended technique
*>use in MGIT 960
NALC or Dithiothreitol > liquetying agent
NaOH ->decontaminant
N-Acetyl-L-cysteine-Sodium Hydroxide (NALCNaOH)
_______ -> liquefies sputum rapidly ; long exposure time to decontaminate
________ -> shortens exposure time and destroys many contaminants
(Zephiran)-Trisodium Phosphate (Z-TSP)
Benzalkonium Chloride
Benzalkonium Chloride (Zephiran)-Trisodium
Phosphate (Z-TSP)
- decontaminate specimens contaminated with P. aeruginosa
5% Oxalic Acid
prolong the shelflife of sputum up to 8 days
* ideal for transport of specimen
1% Cetylpyridium Chloride
Procedure for digestion and decontamination
- Specimen + Digestant
- Mix and stand at room temp for several minutes
- Centrifuge ->SG: 0.79 to 1.07
- Decant
- Sediments for smears and cultures
