Midstream urine specimens should be collected in a sterile plastic container (wax free) with a leak-proof cap for three early mornings. Blood specimens should be collected in a sodium polyanethol sulfonate (SPS) tube and must be treated with lytic agent such as deoxycholate and should be concentrated by centrifugation before inoculating the media. Fluids should be processed promptly and inoculated into a liquid growth medium as well as a solid medium. Biopsy specimens should be immediately sent to the lab (Inderlied, 2004).
It can be expected that specimens collected from nonsterile sites will be contaminated by normal microflora. Therefore, in order to reduce contamination by normal flora, decontamination processes are necessary. The most commonly used mucolytic agents for sputum specimens are freshly-prepared N-acetyl-L-cysteine (NALC) and dithiothreitol (DTT or sputolysin). NALC and sodium hydroxide are generally used for digesting and decontaminating because they kill most bacteria and fungi. Following decontamination, specimens are neutralized with buffer and concentrated by centrifugation. Because swab specimens do not generally contain sufficient materials for culture, 1 g of tissue or 10 ML of fluid are preferred (Inderlied, 2004).
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