University:
Swansea University
Course:
PM134 | Microbiology
Academic year:

2021
Views:

200

Pages:

1
Author:

Prince Sampson

Based on the image provided, here is the text from the Bacterial Identification Flowchart. Bacterial Identification Flowchart GRAM STAIN Positive → (Morphology?) → Cocci (spherical-shaped cells) | | | → Cocci → (Catalase?) → Positive → (Coagulase +/-) → Coagulase +ve → Staphylococcus Aureus (clumps together, shiny beige colonies) → Gram +ve cocci | | | → Coagulase -ve → Staphylococcus Epidermidis & Staphylococcus Saprophyticus (white colonies) | | | → Bacilli (rod-shaped cells) → (Respiration?) → Facultative Anaerobes → (Appearance on MacConkey agar?) → E.coli (pink colonies) & Salmonella spp. (colourless colonies) | | | → Obligate Anaerobes → Clostridium perfringens & Clostridium tetani Additional Notes N.B. May also encounter Candida Albicans (obligate aerobe), a yeast that stains Gram positive. Streptococcus Pyogenes: Lance-field group A, B-hemolysis, penicillin sensitive Streptococcus Pneumoniae: 0.5-1mm colonies α-hemolysis Optochin sensitive Streptococcus Viridans: 0.5-1mm colonies α-hemolysis Optochin resistant Details for the flowchart branches: Gram Positive, Cocci: All are catalase positive, besides Streptococcus. Gram Negative, Cocci: Neisseria gonorrhoeae and Neisseria meningitidis are both Gram negative cocci. Gram Negative, Bacilli: Facultative Anaerobes: The key to differentiating between E.coli and Salmonella is their appearance on a MacConkey agar plate. E.coli turns the agar pink, while Salmonella colonies are colorless. Obligate Anaerobes: Clostridium perfringens (grows in anaerobic conditions, produces toxins, causes gas gangrene) & Clostridium tetani (produces a neurotoxin that causes tetanus). Gram Positive, Bacilli: Obligate Anaerobes and Facultative Anaerobes Obligate Anaerobes: Clostridium perfringens, Clostridium botulinum (causes botulism) Facultative Anaerobes: Bacillus cereus, Bacillus anthracis