Bacteriologic culture in specific media.
See general instructions.
Extraction date is required.
- Insert the cotton swab into the thinner flask and break the stick so that only the swab remains in the bottle.
- Wipe the second dry cotton swab in the same area selected with the first swab.
- Insert the second swab in the flask from the same way as before.
The plates, once collected, will be sealed around with "Parafilm" to avoid the ball caps and possible accidental contamination, and must be transported refrigerated (2-4 º C) and protected from light. Similarly the swabs were sent. In addition, they shall be entered in the date and time of sampling.
The type of specimen sent is required.
Prior sampling considerations
In the environment and in the hands of technicians responsible for sampling, saprophytic microorganisms are present and that may lead to a misinterpretation of cultures due to improper handling of instruments. Hence the importance of using maximum measures of asepsis as well as an established order for sampling, avoiding as much as possible, the accidental contamination of the plates and mistakes in labeling the place where the sample has been obtained.
For all this, it is important to consider the following steps:
- Hand washing and use of sterile gloves.
- Form for data collection; label the plates with the appropriate culture medium and following the pre-established.
- After each sample, seal the used material for the sampling to avoid contamination in situ.
The samples shall be implemented before the start of the surgical activity and upon completion of the hygiene of the area to study, with the least possible number of people present, without opening doors or moving any object while performing the sampling.
The culture media to be used will depend on the sample surface:
in accessible areas are pressing contact plates placed on the surface and hold still, and as evenly as possible during the contact.
In cases of irregular surfaces or difficult access to the contact plates, sterile cotton swabs must be used, and proceed as follows:
- Moisten the cotton swab with liquid transport media.
- Rub cotton swab doing lines together and side to side of the turunda.
- Insert the swab into the diluent's flask and break the stick so that only the swab remains in the bottle.
- Wipe the same area selected with the second swab dry.
- Insert the swab into the same flask and break the stick so that only the swab remains in the bottle.
In cases of flat or regular surfaces proceed the following way:
- Select an area of 100cm² for sampling with the assistance of a template.
- Humidify the cotton swab with the liquid media transport.
- Pressure the template firmly and moving it horizontally and then side to side.
For this reason the choice of the culture medium will also be conditioned and will be studied for each particular case.
Quantitative interpretation of data varies depending on the studied surface. But generally, for bacteria recounts:
a very clean environment would be less than 25UFC/cm ², and an acceptable environment would be less than 50 CFU / cm ².
From the sample can be obtained quantitative data, the number of microorganisms present in a specific surface area (for smooth surfaces or flat:
UFC / cm ², for uneven surfaces: UFC / area sampled). And qualitative data, being the different species of microorganisms that have been collected in the study sample.
The detection limits of microorganisms and the type of pathogen to study, go on the basis of epidemiological data and / or health on the pollutants expected to be encountered in an environment (surfaces in an operating room in a specific location, etc.) But in most cases is not possible prior identification of the microorganism, so it is not ruling out the simultaneous use of both systems (contact plate and swab) to ensure a complete collection of all possible microorganisms.