microbiology Flashcards
Classes of Biosafety 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 I
Classes of Biosafety 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
Classes of Biosafety Cabinet
-self-contained, and 70% of the air is recirculated.
Class IIA
Classes of Biosafety Cabinet
-selected for radioisotopes, toxic chemicals or carcinogenic samples
Class IIB
-very simple microbes, consisting of nucleic acid, a few proteins, and (in some) a lipid envelope.
-completely dependent on the cells they infect for their survival and replication.
virus
-with both RNA and DNA, metabolic machinery for self-replication, and a complex cell wall structure.
Prokaryotic - simple unicellular organisms
bacteria, prokaryotik
-subdivided into single-celled organisms (yeasts) or multi-celled organisms
(molds), with a few medically important members existing in both forms (dimorphic fungi).
fungi
-subdivided into single-celled organisms(protozoa) or multi-celled organisms (worms and bugs).
parasites
• Prokaryotic unicellular organisms that lack a true nucleus and nuclear membrane
• Single, closed, circular chromosomes of double-stranded DNA called
NUCLEOID.
• PLASMIDS: small circular molecules of extrachromosomal circular DNA
• May either be GRAM POSITIVE or GRAM NEGATIVE
BACTERIA
asexual reproduction of bacteria
BINARY FISSION:
size: range from 0.2 to 2um in diameter and 1 to 6um in length
Gram Stain
• Principal stain used for microscopic examination of bacteria
• First devised by Hans Christian Gram during the late 19th century
• Divide most bacterial species into two large groups:
• Gram-positive: take up the basic dye, crystal violet
• Gram-negative: allow crystal violet dye to wash out easily with decolorizer alcohol or acetone
BACTERIA
spherical-shaped cells
COCCI:
rod-shaped cells
BACILLI
spiral shaped cells
SPIRILLA
comma- shaped cells
VIBRIOS
-Process by which bacteria catabolize carbohydrates to produce energy
FERMENTATION
-also known as oxidation
-Process of bacterial energy generation rather than fermentation
RESPIRATION
• Universal Precautions are followed throughout the collection and handling process.
• Persons collecting or handling specimens should wear gloves and a laboratory gown
• Eye protection should also be worn if splashing
• Accidents or injuries (needle prick) must be reported immediately.
Safety
• Specimen should be from the infection site and not contaminated by the surrounding area
• Specimen should be collected before antimicrobials are administered
(Antibiotics)
• Appropriate collection devices and containers should be used and must be
STERILE! ASEPTIC TECHNIQUE is required.
• Specimen container should LABELED with patient’s identification, the date and time of collection and the source of specimen
General Guidelines
• Tongue should be depressed before swabbing between the tonsillar pillars and behind the uvula.
• The cheek, tongue, and teeth should NOT be touched.
Throat (Swabs)
• Expectorated specimens from deep cough should be collected into a sterile specimen cup
• NOTE: Early morning specimens are the best.
Sputum
• Should never be taken from the toilet and should not be contaminated with urine
Stool
• Midstream clean-catch is the most common collection method.
• Culture for catheterized urine specimens usually have less contaminating bacterial flora
Urine
• 2 to 3 cultures should be collected at random times during 24-hour period.
• Skin is disinfected with 70% alcohol, followed by lodine
Blood
