Manual of basic techniques for a health laboratory - libdoc.who.int

5. Bacteriology 205● Parasites: eggs of pulmonary flukes and, very rarely, eggs of schistosomes andadult worms of Mammomonogamus laryngeus.Culture is often necessary for the identification of the infective agents.5.4.1 Materials and reagents●●●●●●●●MicroscopeMicroscope slidesWide-necked, leakproof containers for sputum specimens, such as jars or stiffpaper boxes (see section 2.5.5)Sterile cotton wool swabsTongue depressor or spatulaTest-tubesSodium chloride crystalsN-cetylpyridinium chloride● Distilled water.If possible, sterile cotton wool swabs should be prepared at a central-level laboratory;otherwise, the following technique may be used.1. Prepare some thin sticks of wood (or aluminium wire), 18cm long and 2mm indiameter. Prepare strips of cotton wool, 6cm long by 3cm wide and as thin aspossible.2. Roll the cotton wool round one end of the stick (or wire).3. Mould the swab into a conical shape.4. Place in a glass test-tube. Plug with non-absorbent cotton wool. Sterilize (seesection 3.5.5).5.4.2 MethodCollection of specimensSputum specimensSputum specimens should be collected early in the morning.1. Ask the patient to take a deep breath and then cough deeply, spittingwhat he or she brings up into the container (Fig. 5.18).Secure the top and label the container with the name and number ofthe patient.Check that a sufficient amount of sputum has been produced.2. If the specimen is to be dispatched to a laboratory for culture of Mycobacteriumtuberculosis (see section 5.4.4), ask the patient to expectoratedirectly into a wide-mouthed, screw-topped jar containing 25ml ofthe following solution:N-cetylpyridinium chloride5 gSodium chloride10 gFig. 5.18 Collecting a sputum sampleDistilled water to1000ml.Screw on the top and label the jar with the patient’s name and the date of collectionof the specimen (see section 3.7.1).Important: Liquid frothy saliva and secretions from the nose and pharynx arenot suitable for bacteriological examination. Ask the patient to produce anotherspecimen.