WHAT MICROBIOLOGISTS AND CLINICIANS SHOULD KNOW ABOUT CULTURING WOUND SWABS
Dr.T.V.Rao MD I am certain that we receive 10% of the swabs or discharges for culturing of wounds, the great limitation is who collected, and how it is collected, because it certainly hampers the results, it is most of the times entrusted to junior nursing staff or nursing students without much inputs on what a hound is what is the anatomy of wound, however these matters to be addressed by the Infection control committee,
Clinicians (including nurses, doctors and professionals allied to medicine) have responsibility for the collection and safe transportation of samples to the laboratory. The validity of test results largely depends on good practice in the “pre-test” stage and it is essential that documentation is accurate and comprehensive (Higgins 1994).
ONE MUST FOLLOW THE INSTRUCTIONS AS
Use universal precautions for collecting and handling all specimens.
Obtain the specimen prior to any dressing or cleaning procedure of the wound. This will maximize the material obtained and prevent killing of the organism by the use of antiseptics.
Use a sterile swab and gently rotate on the area to collect exudate from the wound and place into transport medium. Where there is, pus collect as much as possible in a sterile syringe or sterile container (do not use a swab) and send to the laboratory.
For detection of Mycobacterium tuberculosis, pus collected neat in to a pot or tissue biopsy is preferred, however a calcium alginate swab can be used. The alginate swab gradually dissolves maximizing the isolation of the organism as the number of organisms are usually small.
Whenever possible, collect all culture specimens prior to administration of any antimicrobial agents.
When collecting pus, specimens or impressions of wounds obtain as much material as possible as this increases the chance of isolating micro-organisms which may be difficult to grow or are minimal in number e.g. tuberculosis. Pus should be sent in a sterile specimen container, not on a swab
MICROBIOLOGISTS SHOULD NEVER RECEIVE THE SPECIMEN FOR ACID FAST BACILLI ON SWABS .
Specimens should be in tightly sealed, leak proof containers and transported in sealable, leak-proof plastic bags. Specimens for TB should be double bagged. Specimens should not be externally contaminated. Specimens grossly contaminated or compromised may be rejected.
Avoid contamination with indigenous flora. IT IS IMPORTANT IN WOUND SWABS as the surrounding of the wounds are necrotic, we get the bacteria like pseudomonas may be just colonizers and may not be true pathogens, and today many laboratories without quality controls report as drug resistant pseudomonas, Proteus, Serratia Atypical Mycobacteria and many others And it is important make some standard operating procedures, A positive wound culture does not confirm a wound infection. Opportunistic microorganisms may colonize any wound. Wound exudate, which is naturally bactericidal, inhibits the spread of surface contamination from becoming a deep wound infection. However, when wound ischemia or systemic immune compromise supervenes, pathogenic microorganisms propagate until an excessive concentration of bacteria in the wound precludes healing. This heralds a true wound infection. Multidrug resistant organisms are becoming increasingly common.
ALL ILL UNDERSTOOD COLONES TO BE STAINED AND MICROSCOPIC OBSERVATIONS TO BE MADE BEFORE PROCESSING AS PATHOGENS
WHAT CLINICIANS TO UNDERSTAND FROM MICROBIOLOGY REPORTS
Microbiological tests are not as standardized as some other lab tests; the way in which a sample is processed and the results are interpreted depend heavily on the information provided with the specimen.
Please read more at
Ref Specimen collection - microbiology and virology The great Ormond street NHS Hospital for children NHS foundation trust
Dr.T.V.Rao MD Freelance Clinical Microbiologist
Dr.T.V.Rao MD I am certain that we receive 10% of the swabs or discharges for culturing of wounds, the great limitation is who collected, and how it is collected, because it certainly hampers the results, it is most of the times entrusted to junior nursing staff or nursing students without much inputs on what a hound is what is the anatomy of wound, however these matters to be addressed by the Infection control committee,
Clinicians (including nurses, doctors and professionals allied to medicine) have responsibility for the collection and safe transportation of samples to the laboratory. The validity of test results largely depends on good practice in the “pre-test” stage and it is essential that documentation is accurate and comprehensive (Higgins 1994).
ONE MUST FOLLOW THE INSTRUCTIONS AS
Use universal precautions for collecting and handling all specimens.
Obtain the specimen prior to any dressing or cleaning procedure of the wound. This will maximize the material obtained and prevent killing of the organism by the use of antiseptics.
Use a sterile swab and gently rotate on the area to collect exudate from the wound and place into transport medium. Where there is, pus collect as much as possible in a sterile syringe or sterile container (do not use a swab) and send to the laboratory.
For detection of Mycobacterium tuberculosis, pus collected neat in to a pot or tissue biopsy is preferred, however a calcium alginate swab can be used. The alginate swab gradually dissolves maximizing the isolation of the organism as the number of organisms are usually small.
Whenever possible, collect all culture specimens prior to administration of any antimicrobial agents.
When collecting pus, specimens or impressions of wounds obtain as much material as possible as this increases the chance of isolating micro-organisms which may be difficult to grow or are minimal in number e.g. tuberculosis. Pus should be sent in a sterile specimen container, not on a swab
MICROBIOLOGISTS SHOULD NEVER RECEIVE THE SPECIMEN FOR ACID FAST BACILLI ON SWABS .
Specimens should be in tightly sealed, leak proof containers and transported in sealable, leak-proof plastic bags. Specimens for TB should be double bagged. Specimens should not be externally contaminated. Specimens grossly contaminated or compromised may be rejected.
Avoid contamination with indigenous flora. IT IS IMPORTANT IN WOUND SWABS as the surrounding of the wounds are necrotic, we get the bacteria like pseudomonas may be just colonizers and may not be true pathogens, and today many laboratories without quality controls report as drug resistant pseudomonas, Proteus, Serratia Atypical Mycobacteria and many others And it is important make some standard operating procedures, A positive wound culture does not confirm a wound infection. Opportunistic microorganisms may colonize any wound. Wound exudate, which is naturally bactericidal, inhibits the spread of surface contamination from becoming a deep wound infection. However, when wound ischemia or systemic immune compromise supervenes, pathogenic microorganisms propagate until an excessive concentration of bacteria in the wound precludes healing. This heralds a true wound infection. Multidrug resistant organisms are becoming increasingly common.
ALL ILL UNDERSTOOD COLONES TO BE STAINED AND MICROSCOPIC OBSERVATIONS TO BE MADE BEFORE PROCESSING AS PATHOGENS
WHAT CLINICIANS TO UNDERSTAND FROM MICROBIOLOGY REPORTS
Microbiological tests are not as standardized as some other lab tests; the way in which a sample is processed and the results are interpreted depend heavily on the information provided with the specimen.
Please read more at
Ref Specimen collection - microbiology and virology The great Ormond street NHS Hospital for children NHS foundation trust
Dr.T.V.Rao MD Freelance Clinical Microbiologist
No comments:
Post a Comment