From the Guidelines
No, an MRSA DNA amplified probe is not a swab itself, but rather a laboratory testing method used to detect the presence of methicillin-resistant Staphylococcus aureus (MRSA) genetic material. The swab is the collection device used to obtain the patient sample from sites like the nose, throat, or wound, as recommended by guidelines for MRSA screening, which suggest a combination of throat and nasal swab specimens 1. After collection, the swab specimen is processed in a laboratory where DNA amplification techniques such as polymerase chain reaction (PCR) are applied to detect specific DNA sequences unique to MRSA. This molecular diagnostic approach works by making multiple copies of target DNA sequences from the bacteria, allowing for rapid and sensitive detection of MRSA even when present in small quantities. DNA amplification methods typically provide results within hours, compared to traditional culture methods which may take 24-48 hours, enabling faster clinical decision-making for infection control and treatment. Key considerations for implementing MRSA screening include determining who should be screened, when they should be screened, and how they should be screened, with guidelines suggesting that patients at high risk of carriage should be screened at admission and potentially at intervals during their hospitalization 1.
From the Research
MRSA DNA Amplified Probe
- The MRSA DNA amplified probe is a diagnostic tool used to detect methicillin-resistant Staphylococcus aureus (MRSA) in clinical specimens 2, 3, 4, 5.
- This probe can be used in conjunction with a swab to collect samples from patients, which can then be tested for the presence of MRSA 5.
- The use of a single swab for both culture and rapid testing by PCR has been evaluated, and while it is possible, it may not be the most optimal method due to potential inhibition of the PCR reaction 5.
Types of Swabs
- Nasal swabs and wound swabs can be used to collect samples for MRSA testing 2, 5.
- Groin swabs can also be used, especially in cases where patients are at high risk of MRSA colonization 5.
- The type of swab used may affect the sensitivity and specificity of the test results 5.
Sensitivity and Specificity
- The sensitivity and specificity of the MRSA DNA amplified probe can vary depending on the specific test used and the type of sample being tested 3, 5.
- Studies have reported sensitivity and specificity ranges of 57-93% and 86.7-100%, respectively 3, 5.
- The use of a single swab for both culture and rapid testing by PCR may affect the sensitivity and specificity of the test results 5.
Clinical Applications
- The MRSA DNA amplified probe can be used in clinical settings to rapidly identify patients who are colonized or infected with MRSA 2, 5.
- This can help to inform infection control measures and guide treatment decisions 2, 6.
- The use of the MRSA DNA amplified probe can also help to reduce the risk of nosocomial transmission of MRSA 2.