Sunday, October 13, 2013

Transport of Microbiological specimens to the laboratory

Many pathogenic organisms don’t survive for long in clinical specimens kept at room temp. Examples include Gonococci, Haemophilus, Bacteroides, anaerobic cocci and most viruses.
On the other hand, some organisms contaminating specimens from the normal flora such as Coliform and Coagulase negative Staphylococci, may rapidly grow in specimen kept at room temp.
-Urine or sputum specimens should reach the laboratory within 2hours of collection when even possible. If delay are expected immediately inoculated into transport media.
-Transport media used:
Stuart’s transport media ----- for pus or swabs for bacterial culture when delays in transport.>1/2hour or when Neisseria infections are suspected. However the inoculated transport media should be sent to the laboratory within 4h.
The investigation of eye, genital tract is best carried at the bed side when suitable culture media are directly inoculated.
-Cerebrospinal fluid(CSF) not refrigerated since other wise Meningococci may rapidly die.
-Viral transport media is necessary for virus isolation, and also for Chlamydia isolation.
Specimens for virus isolation are kept at –70ºC till time of transferring the appropriate cell line which support growth of the possible virus or Chlamydia.

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