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Identification of Filamentous Bacteria. A Simple Approach. What’s Needed?. A Microscope with phase contrast 10X or 20X Ocular 40X Ocular 100X Ocular (oil immersion lens). Stains. Gram Stain Neisser Stain Sulfur Stain. Gram stain. Separates bacteria into 2 groups Gram (+) and Gram (-)
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Identification of Filamentous Bacteria A Simple Approach
What’s Needed? • A Microscope with phase contrast • 10X or 20X Ocular • 40X Ocular • 100X Ocular (oil immersion lens)
Stains • Gram Stain • Neisser Stain • Sulfur Stain
Gram stain • Separates bacteria into 2 groups • Gram (+) and Gram (-) • Determined by cell wall structure • Gram (+) - purple • Bacterium cell wall retain purple color • Gram (-) - pink • Bacterium cell wall lose purple color
Neisser stain • Separates bacteria in 2 groups • Neisser (+) and Neisser (-) • Distinguishes those filaments with cells that contain granules that accumulate polyphosphate • Neisser (+) - blue • Neisser (-) - brownish
Sulfur stain • Separates bacteria into 2 groups • sulfur deposits • no sulfur deposits
Slide Preparation • Wet Mount • Smear • dried for staining
Cover glass Drop Slide Wet Mount
Puke Too Hard!
Filamentous Bacteria • Normal Permanent residents of activated sludge • Not dominant under normal conditions • Beneficial • Single cell units under normal conditions • Forms filament under certain conditions • Problematic when numerically dominant
Filament Shape Filament Size Cell shape Cell size Cell Septa Indentations Sheath (present/absent) Branching (true/false) Epiphyte (attached growth) Motility Typical Observation
Straight Irregular Smoothly Curved Filament Shape
Filament length Filament width Filament Size
(discoid) (square) (rod-shaped) (rectangle) Bacillus Cell Shape (oval) (round) Cocci
Length of cell Width of cell Cell Size
Cell Septa Septa No septa
Indentations at Septa Noindentations Indentations
Sheath Sheath
Sheath Sheath
True branching Branching
Branching False branching
Attached growth Epiphyte
Motility • The ability to swim • There is only one filament that is motile • Beggiatoa
A Simpler Approach • Foaming • Bulking
BULKING FILAMENTSMajor Characteristics • Staining characteristics • Gram (Neisser, PHB) • Sheath (with or w/o epiphyte) • Sulfur deposits • Motility • Cell shape
BULKING FILAMENTS Gram Stain Gram (+) (purple) Gram Variable Gram (-) (pink) Type 0041 Type 0675 Type 1851 Nostocoida limicola All the rest
Nostocoida limicola • The only Gram (+) filament that causes bulking only • Does not cause foaming • Purple “beaded necklace”
Neisser Stain Neisser (-) (brownish) Neisser (+) (bluish) Nostocoida limicola All others Type 0092 BULKING FILAMENTS
Nostocoida Neisser (+) (low F/M, presence of organic wastes)
Type 0092 Low F/M and long sludge age
Characteristics • Sheath (with or w/o attached growth) • Sulfur Depositors • Motility • Branching (true or false)
Sheath • type 1701 • type 0041 • type 0675 • type 1851 • Sphaerotilus Natans • Thiothrix I & II • Haliscomenobacter hydrossis
Sheath They look alike Both have sausage-shaped cells S. Natans is larger S. Natans exhibits false branching Type 1701 often has attached growth (if you can’t figure the difference, it doesn’t matter because the cause for both is the same - Low DO, also simple carbohydrates and organic acids) S. Natans Type 1701
Sheath They both look alike Type 0041 is larger Both usually has attached growth (Don’t bother to measure, they have a similar cause - Low F:M, long MCRT, Nitrogen and Phosphorus deficiency) Type 0675 Type 0041 The sheath is difficult to detect The filaments are very thin Resembles pins in a pin cushion Associated with low DO, low F:M and nutrient deficiency H. Hydrossis
Sheath This one is easy It normally occurs in bundles It’s common cause is also Low F:M Type 1851 Thiothrix I & II This one is also easy Sulfur granules are usually present The common cause is septic wastes, wastes with an appreciable amount of sulfides and/or organic acids, and wastes deficient in nitrogen
Sulfur Depositors • Type 021N • Thiothrix I & II • Type 0914 • Beggiatoa
Sulfur Depositors Cells are shaped like stacked hockey pucks Indentations at the cell septa Type 021N Cells are rectangular shaped with no indentations at the cell septa Thiothrix This is easy. This filament is the only filament that “swims”. Beggiatoa This filament has rectangular sulfur granules, the others have spherical granules Type 0914
Sulfur Depositors • The common cause of these filaments are: • the presence of reduced sulfur compounds (septic wastes) • wastes deficient in nitrogen • the presence of organic acids
FOAMING FILAMENTS Gram Stain Gram (+) (purple) Gram (-) (pink) Microthrix parvicella Nocardia Type 1863