PAGE 1 FLASHCARDS — ANAEROBE SPECIMEN COLLECTION / TRANSPORT / MEDIA

Acceptable specimens for culture of anaerobes

• Aspirates

• Body fluids

• Bone

• Suprapubic urine
  

  • NOT clean catch

  • NOT catheterized sample

• Tissue

• Wounds using needle & syringe

Best specimen types for anaerobes

⭐ Best / ideal:

• Whole tissue

• Aspiration using needle & syringe

💡 Why:

• best protection from oxygen exposure

Urine specimen acceptable for anaerobes

✅ Suprapubic urine

🚫 Not acceptable:

• Clean catch

• Catheterized urine

Respiratory specimen acceptable for anaerobes

✅ Acceptable:

• Transtracheal aspirate

• Bronchial washings

🚫 Not acceptable:

• Expectorated sputum

• Throat swab

• Nasopharyngeal swab

• Secretions

When is feces used in anaerobe section?

👉 For toxin detection only

Example:

• C. difficile

Most infections involving anaerobes are what?

Polymicrobic

💡 means multiple organisms involved

Presumptive evidence of anaerobic infection

👉 Foul / putrid odor

from tissue specimens and cultures

How should anaerobe specimen collected by needle & syringe be transported?

• Expel excess air

• Seal syringe

• Transport quickly

💡 Oxygen exposure must be minimized

Swabs and anaerobes

🚫 Swabs are least desirable

If used:

• must be transported in anaerobic transport system

Media for culture of anaerobes — general rule

👉 Media can be reduced

to decrease oxygen concentration

Nonselective media for anaerobes

• Brucella agar base

• Brain heart infusion (BHI)

• Columbia with 5% sheep blood

What should anaerobic media contain for recovery of Prevotella melaninogenica?

• Vitamin K

• Hemin

Selective media for anerobic

LKV

BBE

CNA

PEA

LKV agar selects for what?

Laked blood-kanamycin-vancomycin (LKV) selects for:

👉 anaerobic gram-negative bacilli

Especially:

• Bacteroides

• Prevotella

BBE agar selects for what?

Bacteroides bile esculin (BBE) agar selects for:

👉 Bacteroides fragilis group

Why are Bacteroides fragilis colonies black on BBE?

Because the organism hydrolyzes esculin in the media

PEA,CNA ANEROBIC CULTURE SELECTIVE FOR

Gram positive cocci anerobic

Once growth detected on anaerobic media what test should be performed

Aeroltolernace test to determine if the organism anaerobe or falculataive anaerobe

What do anaerobes mean

Mean the organism don’t need oxygen or shouldn’t have oxygen

Anaerobic gram (+) cocci examples

Peptostreptococcus

- Finegoldia

- Peptoniphilus

Normal flora:

- oropharynx

- GI tract

- vagina

- skin

Infections caused by anaerobic gram (+) cocci

Abscesses (skin, soft tissue, brain)

- Aspiration pneumonia

- Necrotizing pneumonia

- Empyema

- Diabetic foot infections

- Crepitant cellulitis

- Necrotizing fasciitis

- Intraabdominal infections

- Septic abortion

What inhibits Peptostreptococcus anaerobius?

SPS (sodium polyanetholsulfonate)

Anaerobic gram (-) cocci

Veillonella

Veillonella Anaerobic gram (-) cocci

Found in oral cavity

- Seen with other organisms in abscesses

- ONLY pathogenic with other bacteria

Identification of anaerobic cocci

- RapidANA

- MALDI-TOF

Differentiation gram POs and gram neg cocci

Van /kan /col (antibiotic )

Catalest test and sps susceptible

Finegoldia magna gram postive cocci anaerobic

Van= sensitive

Kan =variable

Col = resistance

Catalase = neg

Sps = neg

Pepto streptococcus gram postive cocci anaerobe

Van= sensitive

Kan =resistance

Col = resistance

Catalase = -

Sps = +

Peptoniphuuls gram positive cocci anerobic

Van= sensitive

Kan = sensitive

Col = resistant

Catalase = neg

Sps = neg

Veillonelle spp gram neg cocci anaerobe

Van= restistant

Kan = sensitive

Col = sensitive

Catalase = variable -/+

Sps = neg

Anerobic gram postive bacilli spore formers organisms

All of the clostridium family

Clostridium perfringens gram postive bacilli spore formers

- Large gram (+) rods

- “Boxcar shaped”

- Short chains

Causes:

- Food poisoning

- Gas gangrene

- Myonecrosis

- Bacteremia

Lab features:

Double zone β hemolysis

- Lecithinase (+)

Clostridium septicum gram postive bacilli spore formers

key facts

- 2nd most common Clostridium

- Associated with colon cancer / GI pathology

Morphology

Large gram (+) rod

- Forms chains

- Swarming growth

Colonies:

- “Medusa head”

Clostridium botulinum Gram postive bacili spore formers

- Preformed toxin ingested

- Associated with home-canned foods

Diagnosis:

- Detect toxin (NOT organism)

- Wound botulism = spores enter skin

- Infant botulism = raw honey source

Clostridium tetani Gram postive bacili spore formers

Neurotoxin

- Enters via puncture wound

Key:

- Clinical diagnosis

- Lab toxin tests not available

Clostridioides difficile Gram postive bacili spore formers

disease

- Hospital-acquired diarrhea

- Occurs after antibiotic use

- Can be severe

C. difficile culture/colony appearance

- CCFA agar

- Strict anaerobic conditions

- Culture rarely performed

Yellow colonies

- Ground glass appearance

- Fluoresce under UV light

C. difficile smell/C. difficile gram stain

- “Horse manure” odor

- Thin gram (+) or gram-variable rods

- May have subterminal spores

- Free spores present

Anaerobic gram postive rod nonspore formers

Actinomyces

Propionibacterium (Cutibacterium

Bifidobacterium

Actinomyces morphology

Branching, filamentous gram (+) rods

- Looks similar to Nocardia

Non spore formers

Actinomyces key difference from Nocardia

ANAEROBIC

- NOT acid-fast

Actinomyces israelii colony appearance

White colonies

- “Molar tooth” appearance

Cervicofacial actinomycosis cause/ Thoracic actinomycosis cause

- Trauma or surgery/ Aspiration

Female genital actinomycosis association

IUD use

Intraabdominal actinomycosis

Associated with appendicitis

- Diverticulitis

- Surgery

BIG CLUE Actinomyces biochemical

- Catalase (-)

- Indole (-)

Propionibacterium (Cutibacterium acnes)

Non spore /prolly gram postive bacilli rod

- Skin commensal

- Causes infections of prosthetic joints & foreign bodies

- Example: CSF shunt infections

Propionibacterium characteristics

Diphtheroid gram stain appearance

- Produces propionic acid

Big clue Propionibacterium biochemical

- Catalase (+)

- Indole (+)

Bifidobacterium Non spore former gram postive bacili rod

Normal flora of mouth & intestine

- Can cause dental caries

Bifidobacterium morphology

- Pleomorphic gram (+) bacilli

- “Dog biscuit” shaped ends

Bifidobacterium biochemical

BIG CLUE

- Catalase (-)

- Indole (-)

Eubacterium Non spore former gram postive bacili rod

- Infections associated with mouth & colon

Eubacterium morphology/Eubacterium biochemical

- Pleomorphic gram (+) bacilli

- Catalase (-)

- Indole (-)

ANAEROBIC GRAM-NEGATIVE BACILL

Bacteroides fragilis

Porphyromonas / Prevotella

Fusobacterium

Bacteroides fragilis morphology

- Pleomorphic gram neg

- Bacilli → coccobacilli

Bacteroides fragilis

Most common anaerobic pathogen

- Usually polymicrobial infections

Seen in:

- Peritoneal infections (ruptured appendix)

- Post-abdominal surgery

- Bacteremia

Bacteroides fragilis resistance

Produces β-lactamase

- Resistant to penicillin

Bacteroides fragilis special stain feature

Safety pin” appearance

- Bipolar vacuoles

Bacteroides fragilis culture

Blood agar: small, shiny colonies

- BBE agar: BLACK colonies (esculin hydrolysis)

Bacteroides fragilis biochemical

Resistant: vancomycin, kanamycin, colistin

- Catalase (+)

- Indole (-)

Porphyromonas / Prevotella Gram neg bacilli

Normal flora of upper respiratory tract

- Pleomorphic gram (-) bacilli or coccobacilli

Porphyromonas / Prevotella fluorescence

- Brick red fluorescence under UV light

- Colonies appear brown/black in natural light

Porphyromonas vs Prevotella

Porphyromonas:

- Indole (+)

- Vancomycin sensitive

- Pigmented

Prevotella:

- Indole variable (+/-)

- Vancomycin resistant

- Pigmented

Fusobacterium

- Pleomorphic gram (-) bacilli & coccobacilli

Fusobacterium

Normal flora of oral cavity

Fusobacterium necrophorum

Colonizes tonsils

- Causes Lemierre syndrome

(septic thrombophlebitis of internal jugular vein)

- Associated with Vincent angina

Fusobacterium. n lab features

- Produces lipase on egg yolk agar

- Colony: rainbow sheen

- Indole (+)

Fusobacterium nucleatum biochemical

Lipase (-)

- Indole (+)

Bacteroides fragilis profile

- Vancomycin: R

- Kanamycin: R

- Colistin: R

- Bile esculin: +

- Indole: -

- Catalase: +

- Fluorescence: none

Fusobacterium spp profile

Vancomycin: R

- Kanamycin: S

- Colistin: S

- Bile esculin: -

- Indole: +

- Catalase: -

- Fluorescence: chartreuse

Porphyromonas asaccharolytica profile

Vancomycin: S

- Kanamycin: R

- Colistin: R

- Bile esculin: -

- Indole: +

- Catalase: -

- Fluorescence: red

Prevotella melaninogenica profile

Vancomycin: R

- Kanamycin: R

- Colistin: V (variable)

- Bile esculin: -

- Indole: -

- Catalase: -

- Fluorescence: red

Spirochetes

- Spiral / corkscrew shape

- Helical bacteria

- VERY thin

Soirochetes organism

Treponema pallidum

Borrelia

Leptospira interrogans

Spirochetes gram stain

Do NOT stain well with Gram stain

- Too thin to visualize

Spirochetes visualization

Darkfield microscopy

- Special staining methods

Spirochetes location

Extracellular

- Live outside the cell

Treponema pallidum

Causes syphilis

Primary syphilis

Painless chancre

- At site of infection

- Lasts ~1–6 weeks

Secondary syphilis

Flu-like symptoms

- Rash

- Lymphadenopathy

Tertiary syphilis

Gummas (lesions)

- Brain damage

- Heart damage

Syphilis screening tests

- RPR

- VDRL

Syphilis confirmatory tests

- FTA-ABS

- TP-PA

Syphilis test interpretation

- Nontreponemal tests ↓ after treatment

- Treponemal tests stay positive

Borrelia

Causes Lyme disease

- Found in North America & Europe

Borrelia morphology

Loosely coiled

- Corkscrew motility

Lyme disease vector/ borrelia

Tick bite

Reservoir:

- Mice

- Deer

Lyme disease stages

Early:

- Bullseye rash (erythema migrans)

Late:

- Heart problems

- Neurologic issues

- Arthritis

Lyme disease testing

Screening: EIA / IFA

- Confirm: Western blot

Leptospira interrogans

Tightly coiled spirochete

- Hooked ends

Leptospira transmission

Animal urine

- Enters through cuts in skin

Common host:

- Rats

Leptospira disease/Leptospira symptoms and diagnose

Weil disease

Symptoms:- Meningitis

- Hepatitis

- Nephritis

diagnosis:

- ELISA

Intracellular organisms key concept

Live INSIDE host cells

- Cannot grow on routine media easily

Name Intracellular organisms

Chlamydia

Rickettsiae

Chlamydia trachomatis

Most common STD in U.S.

- Often asymptomatic

Chlamydia trachomatis specimen

- Urethral swab

- Cervical swab

- Urine

Chlamydia trachomatis diseases/ diagnosis

- Trachoma

- LGV

- Urethritis

- Cervicitis

- Neonatal infections

Diagnosis:

- NAAT (MOST important)

- Cell culture (old gold standard)

Chlamydia psittaci

- Psittacosis

- Associated with birds

- Pneumonia

Chlamydia pneumoniae

Pneumonia

- Pharyngitis

- Bronchitis

- Diagnosed by MIF