Microbiology

Hi everybody! Time pssed so fast, SIP is going to end soon!
This week, I am going to share something in the microbiology lab.
Microbiology lab is a place where safety issues are particular important. So I want to talk about the four-biosafety levels.

Biosafety level 1
Biosafety Level 1 is suitable for work involving well-characterized agents not known to consistently cause disease in healthy adult humans, and of minimal potential hazard to laboratory personnel and the environment. Work is generally conducted on open bench tops using standard microbiological practices. Laboratory personnel have specific training in the procedures conducted in the laboratory.(Eg: normal routine bench in the microbiology lab)

Biosafety level 2
Biosafety Level 2 is similar to Biosafety Level 1 and is suitable for work involving agents of moderate potential hazard to personnel and the environment. It differs from BSL-1 in that laboratory personnel have specific training in handling pathogenic agents and are directed by competent scientists; access to the laboratory is limited when work is being conducted.
Certain procedures in which infectious aerosols or splashes may be created are conducted in biological safety cabinets.(Eg: the bench working on the respiratory specimen)

Biosafetty level 3
Biosafety Level 3 is applicable to the place where work is done with exotic agents which may cause serious or potentially lethal disease through the inhalation route. Laboratory personnel have specific training in handling pathogenic and potentially lethal agents, and are supervised by competent scientists who are experienced in working with these agents. All procedures involving the manipulation of infectious materials are conducted within biological safety cabinets or other physical containment devices, or by personnel wearing appropriate personal protective clothing and equipment. The laboratory has special engineering and design features.

Biosafety level 4
Biosafety Level 4 is required for work with dangerous and exotic agents that pose a high individual risk of aerosol-transmitted laboratory infections and life-threatening disease. The laboratory director strictly controls the access to the laboratory. The facility is either in a separate building or in a controlled area within a building, which is completely isolated from all other areas of the building.

I want to share one more biochemistry test kit in the micro-lab also. It is PYR rapid colorimetric test.

PYR
PYR is a rapid colorimetric test for the determination of PYRase activity in Streptococci and Citrobacter spp. PYRase activity distinguishes Group A streptococci and enterococci from other streptococcal groups including Group D streptococci.
PYR test kit uses Test Cards impregnated with L-pyroglutamic acid 7-amino-4-methyl-coumarin (7AMC) and dimethylamino-cinnamaldehyde for the detection of PYRase activity. The enzymatic hydrolysis of this substrate by enterococci, Group A streptococci and Citrobacter spp. produces a purple colour followed by the addition of the Developing Solution.

Specimen preparation
When identifying enterococci and Group A streptococci, fresh primary or secondary cultures grown overnight on non selective media such as blood agar give best results. Colonies tested must be Gram-positive cocci and catalase-negative. In case of insufficient growth, a subculture should be performed.When identifying Citrobacter spp. from Salmonella spp. and Enterbacteriaceae, colonies from non-selective media such as (XLD Medium, MLCB Agar, Desoxycholate Citrate Agar, Salmonella Shigella Agar, Brilliant Green Agar or Hektoen Enteric Agar) may be tested. Colonies should be Gram-negative, oxidase-negative and urease-negative.

Test procedure
1. Apply one suspect colony (0.5mm or larger) onto the test area (enough to make a visible smear).

2. Moisten test area with 1 drop of Buffer.

3. Incubate the inoculated Test Card at room temperature (15-30°C) for 5 minutes.

4. Dispense I drop of Developing solution onto the test area. Development of a vivid purple colour on and around the colonies within 20 seconds confirms PYRase activity.

www.labcenter.com.br/novidades.htm

ok that's all~

Enjoy reading:)

Liu Qian

0503935I