1.Purpose: To take secretions from the pharynx and tonsils for bacterial culture or viral isolation to assist in diagnosis.
2. Materials used Sterile throat swab culture tube, alcohol lamp, matches, sterile saline, tongue depressor.
3. Methods of operation Prepare all the supplies, label them well, and explain the purpose and methods of cooperation to the patient in order to obtain cooperation. Light the alcohol lamp, the swab out dipped in sterile saline (if necessary, with a tongue depressor gently press the tongue), asked the patient to send "ah" sound to make the mouth open wide, with brisk movements, quickly wipe both sides of the palatal arches and pharyngeal, tonsil secretions, quickly disinfect the mouth of the test tube on the flame of the alcohol lamp, the swab will be inserted into the test tube tightly plugged and immediately sent for testing. After the test, inoculation was carried out, planted on the culture medium and put into the incubator.
4. Precautions pharyngeal swab culture, should be in the early morning after first rinsing with saline (about 1%), before sampling specimens, so that the oral cavity can be cleaned out of bacteria, in order to accurately find out the upper respiratory tract and the lower respiratory tract infections bacteria.
5. Others If pathogenic bacteria are detected in sputum and pharyngeal swab secretions, it is considered a respiratory tract infection. The site of respiratory tract infection can be diagnosed in combination with other tests (X-ray, ultrasound, etc.). Common bacteria in respiratory tract infections include staphylococcus, pneumococcus, Haemophilus influenzae, Klebsiella pneumoniae, staphylococcus, streptococcus, Pseudomonas aeruginosa, Escherichia coli, and so on. If Mycobacterium tuberculosis is detected in the culture, then it is tuberculosis. If the culture of yeast-like bacteria, then consider whether the use of antibiotics during the infection is inappropriate or overdose, should immediately stop using antibiotics, switch to antifungal drugs, such as amphotericin B, ashwagandha, clotrimazole and so on.
6. It can be identified according to the following characteristics
(1) If there is a hemolytic ring around the colony which is 2~4mm wide, clearly defined and completely transparent, and the smear is gram-positive coccus and is arranged in a chain, then it may be beta-hemolytic streptococcus.
(2) Small, translucent colonies with a grass-green hemolytic ring and gram-positive cocci arranged in chains may be type A hemolytic streptococci. When further differentiation from pneumococcus is needed, bile lysis test and inulin fermentation reaction can be done.
(3) If the colonies are small and translucent, not hemolytic, and the smear is a gram-positive, chain-like arrangement of the cocci, it is streptococcus C. The results of this study are summarized in the following table.
(4) When the colonies are flat with raised edges and slightly concave centers, translucent, grass-green hemolytic, Gram-positive diplocococci, and arranged in spearheads, they are pneumococci, and should be differentiated from A-hemolytic streptococci by bile lysis and inulin fermentation reaction.
(5) If the colonies are medium-sized, smooth, gray, Gram-negative diplocococci, and arranged in a kidney shape, they may be meningococci, and need to be further tested for the oxidase test and the sugar fermentation test (inoculated in serum-containing tubes of glucose, maltose, and sucrose fermentation tubes).
(I) Chlamydia pneumonia
Nasopharyngeal swab smears stained with Giemsa's stain show iodine-stained intracytoplasmic inclusions of the pathogen; cell culture is used to isolate the pathogen; double serum checks for antibodies or antigen detection can help diagnosis; or monoclonal antibodies are used to make a rapid diagnosis by direct fluorescent staining or ELISA for antigen detection.
(2)Fungal pneumonia
1.Candida pneumonia
(1)Fungal examination: pharyngeal swabs, sputum, feces, focal tissue or pseudomembrane, exudate, etc. can be.
(2) direct smear microscopy: put a little of the above specimen on a slide, add 1 drop of 10% potassium hydroxide, put a coverslip and heat it slightly, then microscopy, you can see the pseudohyphae and spores. Because healthy people can carry bacteria, must be repeatedly positive microscopy or in the part of the bacteria usually do not parasitize the specimen, positive microscopy to have diagnostic significance.
(3) Fungal culture: the above specimens can be inoculated with the commonly used fungal culture medium (Shah's medium) at the same time. Most in 3~4d appeared milky white smooth colonies, such as the number of colonies 50% is diagnostic significance.
2. Pulmonary aspergillosis
(1) direct smear examination: the specimen obtained from the affected area, make a direct smear, microscopic examination can be seen mycelium or Aspergillus spores.
(2) culture: sputum, blood, local damaged tissues can do Aspergillus culture. Aspergillus is a common contaminant in the laboratory, so only repeated culture of the same Aspergillus and combined with clinical manifestations, before the diagnostic value.
(C) capillary bronchiolitis
Nasopharyngeal swab bacterial culture is not significantly different from that of healthy children (both can be bacterial).