Rotation - Anaerobic organisms

Clostridium perfringens

Large “boxcar” GPR, double zone hemolysis, lecithinase positive, causes gas gangrene

Clostridium septicum

Swarming colonies, subterminal spores, associated with colon malignancy, causes myonecrosis

Clostridium ramosum

Terminal spores, often stains gram negative, resistant to penicillin and clindamycin

Clostridium botulinum

Produces neurotoxin blocking acetylcholine release, causes foodborne botulism

Clostridium tetani

Terminal “tennis racket” spores, causes tetanus with muscle rigidity and lockjaw

Actinomyces israelii

Branching GPR, molar tooth colonies, sulfur granules, causes cervicofacial and abdominal actinomycosis

Bifidobacterium

Y-shaped bifurcated gram-positive rods, normal flora, can cause head and neck infections

Eubacterium lentum

Small gram-positive rods, normal oral and intestinal flora, part of mixed anaerobic infections

Propionibacterium (Cutibacterium) acnes

Pleomorphic GPR, catalase positive and indole positive, causes shunt infections and blood culture contamination

Lactobacillus

Long chaining gram-positive rods, microaerophilic, normal female genital flora

Peptostreptococcus anaerobius

SPS disk sensitive and sweet odor, causes abdominal, brain, lung, and skin abscesses

Anaerococcus

Anaerobic gram-positive cocci found in GU and intestinal flora, involved in mixed infections

Fingoldia magna

Anaerobic gram-positive coccus involved in skin and soft tissue infections

Peptoniphilus

Anaerobic gram-positive coccus found in GU and skin infections

Bacteroides fragilis group

Pleomorphic GNR, ground-glass colonies, resistant to penicillin, kanamycin, vancomycin, and colistin, most common anaerobe in infections

Bacteroides ureolyticus

Pitting colonies, urea positive, vancomycin resistant, causes head, neck, and abdominal infections

Prevotella melaninogenica

Black pigment and brick-red fluorescence, bile negative, causes head, neck, lung, and abdominal infections

Fusobacterium nucleatum

Tapered rod ends, chartreuse fluorescence, indole positive, causes head and neck infections

Fusobacterium necrophorum

Most pathogenic Fusobacterium species, frequently isolated alone

Fusobacterium mortiferum

Highly pleomorphic GNR with fried-egg colonies, causes mixed infections

Porphyromonas species

Black pigment, brick-red fluorescence, resistant to kanamycin and colistin but vancomycin sensitive

Veillonella parvula

Small GNC, nitrate positive, vancomycin resistant, brick-red fluorescence, causes head and neck infections

Acidaminococcus

Anaerobic gram-negative coccus, normal intestinal flora

Megasphaera

Anaerobic gram-negative coccus, normal intestinal flora