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Fastidious Bacteria


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What is the smallest of the small bacteria?
What is their distinguishing feature?
Identifier: lack a cell wall
What growth conditions are necessary for mycoplasma?
Media must contain:
-serum (for protein)
-Increased CO2
-Up to 1 month
How is mycoplasma identified?
Stereomicroscope -> fried egg morphology of tiny colonies.

DIENES STAIN -> short blue bacilli (GS does not work)

-Immunologic ID is best.
most pathogenic member of mycoplasma:
Mycoplasma pneumoniae
What disease does M. pneumoniae cause?
What antibiotic treats this?

-Walking pneumonia in young adults
What are 3 methods for detecting M. pneumoniae?
1. EIA
2. Cold agglutinins (50%)
3. Nucleic acid probe I.D.
what are 4 species of mycoplasma other than pneumoniae?
M. hominis
M. genitalium
M. fermentens
M. salivarium
What species of Mycoplasma are genital pathogens?
M. hominis
M. genitalium
Where is M. fermentens found?
Where is M. salivarium normal flora?
In the oral cavity.
name of genital tract pathogen related to mycoplasma:
ureaplasma urealyticum
Essence of L-forms
lack a cell wall but due to a condition that caused it:
1. high conc. of penicillin
2. high conc. of salt
type of bacteria that easily becomes

what does it cause?
Streptobacillus moniliformis

causes rat bite fever
How many types of legionella are there?
Most common?
Commonly found in:
about 40 species
L. pneumophila
What does legionella pneumophila mean?
Little legions of lung-loving bacteria
What disease is caused by l. pneumophila?
severe Acute Respiratory disease
How is L. pneumoniphila transmitted?

Who is it most commonly seen in?
Inhalation/aspiration of H2O

Middle aged men - they smoke
Why was L. pneumophila hard to find?
It doesn't stain! they could never find it in all those samples
How does a L. pneumophila infection progress re: sx?

What is it treated with?
-Starts w/ flu-like symptoms, high fever develops, then into
Lobar pneumonia w much sputum.
-Treat with erythromycin

What is Pontiac fever?
A milder form of Legionnaire's disease caused by an antigenic variant.
what specimen is tested for L. pneumophila?
sputum; can be hard to get, so induce it.
-What growth factor is needed for culturing Legionella?
-What agar is used?
-Agar: BCYE - buffered charcoal yeast extract media
what are the cultural (growth) characteristics of L. pneumophila?
1st inoculate the plain BCYE: shouldn't see growth. Allows presumptive I.D.

2nd inoculate BCYE + cystine; then should see growth.
Growth requires 3-4 days and results in ground glass appearance of colonies
Name 3 methods for ID of Legionella:
1. Growth on BCYE+cystine
2. Flourescent Ab Test
a. Direct (specimen/culture)
b. Indirect (serum - both conval. and acute phase)
3. Nucleic acid probes - PCR
Legionella is
Cat +
Oxi weakly +
chemical component that causes Acid fastness:
mycolic acid
What genus is acid fast bacilli?
What 5 types of specimens can be tested for mycobacterium?
1. Sputum, bronchoalveolar lavage, bronchial washings.
2. Gastric secretions (neutralize imm.)
3. Urine
4. Tissue, CSF, Blood
5. Skin

First morning specimens always
what are the OSHA requirements for mycobacterium processing
1. neg air flow room -
biosafety level 3 room
2. Biolog. safety cabinet
3. Wear gowns, gloves, respirators
4. Skin test personnel ev. 6 months
whats the most important, first test you must do when testing for mycobacterium?
DIRECT SMEAR - growth takes so long, this is the best way for fast info.
what are 2 types of direct smears you can do for mycobacterium:
-Acid fast: Kinyoun or Ziehl-neelson; must examine at least 15 min or 300 fields; easy to miss the bug on a TB smear.

-Flourescent: easier, but background/garbage also messes up
How to process a gastric or sputum culture for mycobacterium:
1. NALC NAOH - digest mucous, decontaminate specimen, get rid of normal oral flora.
2. Trisodium phosphate + benzalkonium chloride; but #1 is better
How to process a urine specimen for mycobacterium:
concentrate it by centrifugin
What media is used for isolating Mycobacterium?
-Lowenstein Jensen
-Broth AND Agar, can add antibiotics.
What incubation conditions apply to Mycobacterium cult?
(skin, other)(temp and time)
Skin: 30 C
All else: 37 C
Increased CO2
at least 8 weeks before calling neg!
What 3 things should be done if specimen with suspected mycobacterium grows?
1. Check for acid fastness
2. check colony morph; if unpigment, expose to light, reincubate.
3. record time required for growth

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