Gram Negative bacteria  Cocci: The family Neisseriaceae comprises the genera Neisseria, Moraxella, Kingella, and Acinetobacter. The only significant human pathogens are N gonorrhoeae, the agent of gonorrhea, and N. meningitidis, an agent of acute bacterial meningitidis. N gonorrhoeae infections have a high prevalence and low mortality, whereas N meningitidis infections have a low prevalence and high mortality. Moraxella is an oxidase-positive bacterium, sometimes mistaken for Neisseria, that may be isolated from eye infections and respiratory tract infections. Moraxella catarrhalis causes lower respiratory infection in adults with chronic lung disease and is a common cause of otitis media, sinusitis, and conjunctivitis in children. Kingella and Eikenella species are short bacilli or coccoid bacteria that act as opportunistic pathogens. They are sometimes secondary invaders of damaged tissues

Pseudomonas aeruginosa Gram

• Gram –Ve diplococci .

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Gram stain:(or Gram’s method) is a method of differentiating bacterial species into two large groups (Gram positive and Gram negative).

Gram Stain

It is based on the chemical and physical properties of their cell walls. Primarily, it detects peptidoglycan, which is present in a thick layer in Gram positive bacteria. A Gram positive results in a purple/blue color while a Gram negative results in a pink/red color.
The Gram stain is almost always the first step in the identification of a bacterial organism, and is the default stain performed by laboratories over a sample when no specific culture is referred.
While Gram staining is a valuable diagnostic tool in both clinical and research settings, not all bacteria can be definitively classified by this technique, thus forming Gram-variable and Gram-indeterminate groups as well.
The word Gram is always spelled with a capital, referring to Hans Christian Gram, the inventor of Gram staining.

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Gram positive bacteria: are those that are stained dark blue or violet by Gram staining. This is in contrast to Gram-negative bacteria, which cannot retain the crystal violet stain, instead taking up the counterstain (safranin or fuchsine) and appearing red or pink. Gram-positive organisms are able to retain the crystal violet stain because of the high amount of peptidoglycan in the cell wall. Gram-positive cell walls typically lack the outer membrane found in Gram negative bacteria.

 Characteristics

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Clostridium botulinum : Bacteria of the family Clostridium SPP Of a group gram positive bacilli

Characteristics

•  larg Gr +Ve bacilli
  

  Clostridium botulinum

•  sporng , motile bacilli
•  sporing are oval , terminal or subterminal & projecting
•  non capsulate bacilli
•  obligate anaerobes
•  fastidious growth.

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Clostridium difficile : Bacteria of the family Clostridium SPP Of a group gram positive bacilli.

Characteristics

•  larg Gr+ Ve bacilli usually arranged in chain
  

  Clostridium difficile

•  sporing , motile bacilli
•  spores are oval
•  obligate anaerobes
•  part of the normal intestinal flora

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Clostridium perfringens : Bacteria of the family Clostridium SPP Of a group gram positive bacilli

Characteristics

•  relatively larg Gr + Ve bacilli , usually arranged
  

  Clostridium perfringens

• in chain
•  non motile bacilli & capsulate bacilli
•  spores are oval , subterminal & non – projecting
•  spores rarely seen in infected materials
•  anaerobes , but it can tolerate exposure to air for short time
•  hemolytic in culture.
•  Replicate rapidly

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Clostridium tetani : Bacteria of the family Clostridium SPP Of a group gram positive bacilli

Characteristics

•  larg Gr+ Ve bacilli
•  sporing , motile bacilli
  

  Clostridium tetani

•  spores are spherical , terminal ( drumstick )
•  non capsulate bacilli
•  obligate anaerobes
•  difficult to grow.because the organism is extremely sensitive to oxygen toxicity.
•  Not ferment carbohydrates.

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Clostridium SPP : Clostridium SPP:is a genus of Gram-positive bacteria, belonging to the Firmicutes. They are obligate anaerobes capable of producing endospores (Anaerobic, spore-forming,Gram-positive Rods) .

• All anaerobic, gram-positive rods capable of forming endospores was placed in the genus ” Clostridium “
• -Clostridium spp was defined by four properties

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corynebacterium gram positive bacilli : Group of bacteria gram positive bacilli

Characteristics

•  gram +Ve bacilli (( club shaped )) .
•  aerobic and faculitative anaerobic .
•  non spore forming .
•  non Acid fast .
•  non motile .

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Corynebacterium diphtheriae: bacteria gram positive bacilli Non Acid Fast or None Spore

Characteristics

• Gr+ Ve Polymorphic bacilli (club-shaped) .
• cells appear in chineses-letter arrangement .
• non capsulate , non sporing , non motile .
• Facultative anaerobes .
• Ferment carbohydrate .
•  Most grow well in lipid free media .

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