Specimen collection
1. Open infections and ulcerated septic foci: swab the surface exudate with sterilized saline before specimen collection, use aspiration or swab as deep as possible into the wound, sample closely to the wound front, and sample from the bottom of the abscess or abscess wall for more effect. For chronic infection with severe contamination, it is difficult to isolate the causative organism, and the tissue under the infected site can be taken and ground into a tissue homogenate to be inoculated in a suitable medium.
2. Closed abscess: After local disinfection, aspirate the abscess wall with a needle and syringe, place all the material in a sterile test tube and send it for examination, and if anaerobic infection is suspected, immediately make bedside inoculation or place it in an anaerobic transfer device for examination (the laboratory department has not carried out routine anaerobic bacteria culture for the time being, if necessary, please contact the laboratory department). However, when taking samples, it may bring in colonized bacteria that are not related to the infection process.
3. Large trauma infection: take the infected tissue block or inner dressing stained with pus to send for examination.
Precautions
When bacteria are sensitive to dryness or only a small amount of specimens can be collected, put the specimens into liquid medium immediately after collection with cotton swabs, or dip the cotton swabs into a small amount of sterile saline before collecting the specimens to maintain humidity.
For specimens that cannot be sent for immediate examination, they should be stored at 4°C, with the exception of caustic specimens such as Neisseria gonorrhoeae and Neisseria meningitidis.
Specimens should be collected prior to drug administration whenever possible.
Local use of antimicrobial drugs or disinfectants should be avoided in the lesion before sampling.
Gram staining is performed to evaluate the specimen. The presence of epithelial cells in the smear indicates that the specimen is contaminated. The absence of epithelial cells and the presence of leukocytes indicates that the specimen was
was collected correctly.
All traumas can be contaminated with bacteria, but infection does not necessarily occur, so the isolated bacteria should be evaluated according to the condition of the trauma, the amount and species of bacteria, the processing of the collected specimens, and the mechanism of infection.
Therefore, the isolated bacteria should be analyzed and judged according to the situation of trauma, the amount and number of bacteria, the process of collecting specimens, the immunity of the body and the use of antibiotics.
Specimens should be transported in sterile containers or swabs, at room temperature, within 1 hour.
Tissue and aspirates are preferred over swab specimens
Specimens in as large a volume as possible, simple surface rubbing swabs do not qualify
Application form must indicate site of pus and secretion production
