It is important not to assume that:
(1) a swab and transport system will work.
(2) a swab and transport system that works for one micro-organism will work for another.
Problems that occur with various swabs:
(1) toxic effect on micro-organisms
(2) toxic effect on tissue culture cells required for growth of the microorganism
(3) inhibition of amplification during PCR or other molecular analysis
Problems with various transport systems:
(1) drying out of the swab
(2) failure to control extremes in pH with adequate buffering
(3) failure to maintain on optimum osmolarity for the organism
(4) failure to support the organism during transport
(5) failure to maintain a proper temperature
(6) failure to maintain an optimum atmosphere that is nontoxic for the organism
Materials in swabs may include:
(1) calcium alginate (made by addition of calcium chloride with calcium alginate)
(2) cotton
(3) synthetic fiber
(4) wooden shaft
(5) aluminum or other metal shaft
The evaluation may include:
(1) sterility of an unused system
(2) a positive result with known or spiked samples, with an adequate detection threshold
If an unexpected result occurred it is important to determine the cause.
