MYCROBIO AND VIRO

• CLASS I cabinet

  • Allow room air to pass into cabinet and around the area and material within, sterilizing only the air to be exhausted
  • Consist of negative pressure
  • Operated in open front
• CLASS II cabinet

  • Air flows in “sheets”, which serves as a barrier to particle from outside the cabinet
  • Direct the flow of contaminated air into the filters
  • also called as VERTICAL LAMINAR FLOW BSCs
• CLASS II A cabinet - Self-contained, and 70% of the air is recirculated [most common in clinical microbiology section]
• CLASS II B cabinet - Selected for radioisotopes, toxic chemicals or carcinogenic samples
• BACTERIA - Prokaryotic unicellular organisms that lack a true

  nucleus and nuclear membrane
• NUCLEOID - Single, closed, circular chromosomes of double-stranded DNA
• PLASMIDS - small circular molecules or extrachromosomal circular DNA
• BINARY FISSION - asexual reproduction of bacteria
• Bacteria size ranges from 0.2 to 2 um in diameter and 1 to 6 um in length
• GRAM STAIN - Principal stain used for microscopic examination of

  bacteria. First devised by Hans Christian Gram during the late 19th century
• Gram-positive - take up the basic dye, crystal violet
• Gram-negative - allow crystal violet dye to wash out easily with decolorizer alcohol or acetone
• Cell wall in Gram positive - Thick (Peptidoglycan)
• Cell wall in Gram negative - Thin (Peptidoglycan)
• Lipopolysaccharide in Gram positive - Absence
• Lipopolysaccharide in Gram negative - Presence
• Gram staining in Gram positive - Purple
• Gram staining in Gram negative - red or pink
• Representation of Gram positive - Purple or Violet result
• Representation in Gram negative - Pink result
• COCCI - spherical-shaped cells
• BACILLI - rod-shaped cells
• SPIRILLA - spiral shaped cells
• VIBRIOS - comma-shaped cells
• Coccobacillus - Short rod shaped cells
• Spirochete - long, loose, helical spiral shaped cells
• FERMENTATION - Process by which bacteria catabolize carbohydrates to produce energy
• RESPIRATION - Also known as oxidation. Process of bacterial energy generation rather than fermentation
• Universal Precaution - needed to be followed throughout the collection and handling process
• THROAT (SWABS)

  • Tongue should be depressed before swabbing between the tonsillar pillars and behind the uvula

  • The cheek, tongue, and teeth should NOT be touched
• SPUTUM

  • Expectorated specimens from deep cough should be collected into a sterile specimen cup
• STOOL - should never be taken from the toilet and should not be contaminated with urine
• URINE

  • Midstream clean-catch is the most common collection method

  • Culture for catheterized urine specimens usually have less contaminating bacterial flora
• Blood - 2-3 cultures should be collected at random times during 24-hour period using venipuncture
• ADULTS: 20-30mL of blood per culture is collected
• INFANTS: 1-5mL of blood per culture is collected
• CEREBROSPINAL FLUID

  • Should be collected aseptically by PHYSICIAN

  • Should be processed immediately and not exposed to heat or refrigeration
• MEN (penile discharge)

  • Exudates may be expressed from the urethral orifice or a small-diameter swab inserted 3-4 cm into the urethra
• WOMEN (vaginal discharge)

  • A sterile swab is inserted into the cervix with an aid of speculum
  • Swab is rotated and allowed to remain for a few seconds
• Aerobic set-up - okay to be exposed in oxygen