From the Guidelines
Real-time PCR is the most recommended molecular technique for detecting Carbapenem Resistant Enterobacterales (CRE) due to its rapid turnaround time, high sensitivity and specificity, and ability to quantify bacterial load and detect multiple resistance genes in a single reaction. Polymerase Chain Reaction (PCR) is a molecular technique that amplifies specific DNA sequences, making it valuable for detecting antibiotic resistance genes in bacteria. For CRE, PCR testing is essential for rapid identification, allowing for appropriate infection control measures and treatment decisions. Several PCR types are used in clinical microbiology, including conventional PCR, multiplex PCR, and real-time PCR. Real-time PCR targets common carbapenemase genes such as KPC, NDM, OXA-48, VIM, and IMP.
Key Points
- The use of molecular tests, such as real-time PCR, is strongly recommended for patients colonized or potentially infected with CRE, as it is associated with a more rapid administration of appropriate antimicrobial therapy and can lead to a reduction in mortality 1.
- Real-time PCR has a rapid turnaround time of 1-3 hours, which is significantly faster than culture-based methods that can take 24-72 hours.
- Commercial real-time PCR assays are available for CRE detection, offering standardized protocols that can be implemented in clinical laboratories.
- Phenotypic tests, such as combined disc test (CDT) and modified carbapenem inactivation method (mCIM), are also highly sensitive and specific in detecting carbapenemases and are highly consistent with genotypic tests 1.
Detection of CRE
The detection of CRE is critical for preventing the spread of these resistant bacteria and for guiding appropriate treatment. Real-time PCR is a valuable tool in this effort, offering a rapid and accurate means of identifying CRE. The advantages of real-time PCR include:
- High sensitivity and specificity
- Rapid turnaround time
- Ability to quantify bacterial load
- Capacity to detect multiple resistance genes in a single reaction Overall, real-time PCR is a crucial tool in the detection and management of CRE infections, and its use is strongly recommended in clinical practice 1.
From the Research
PCR and its Types
- PCR (Polymerase Chain Reaction) is a molecular biology technique used to amplify specific DNA sequences.
- Real-time PCR is a type of PCR that allows for the simultaneous amplification and detection of DNA sequences, making it a valuable tool for the rapid detection of pathogens, including carbapenem-resistant Enterobacteriaceae (CRE) 2, 3, 4.
Real-Time PCR for Detection of Carbapenem-Resistant Enterobacteriaceae
- Real-time PCR can be used to detect the presence of carbapenemase genes in Enterobacteriaceae, which are responsible for carbapenem resistance 3, 4.
- The Xpert Carba-R assay is a real-time PCR test that can detect the presence of carbapenemase genes, including KPC, NDM, VIM, IMP, and OXA-48 3.
- Real-time PCR has been shown to be a rapid and sensitive method for detecting carbapenem-resistant Enterobacteriaceae, with sensitivity and specificity rates comparable to other diagnostic methods 3, 4.
Comparison of Diagnostic Methods for Detecting Carbapenem-Resistant Enterobacteriaceae
- Several diagnostic methods are available for detecting carbapenem-resistant Enterobacteriaceae, including PCR, matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF MS), and phenotypic methods such as the Carba NP test and the modified Hodge test (MHT) 3, 5.
- Each method has its own advantages and disadvantages, and the choice of method depends on the specific needs of the laboratory and the clinical setting 3, 5.
- Real-time PCR has been shown to be a valuable tool for the rapid detection of carbapenem-resistant Enterobacteriaceae, and can be used in conjunction with other diagnostic methods to improve detection rates 3, 4.
Importance of Rapid Detection of Carbapenem-Resistant Enterobacteriaceae
- Rapid detection of carbapenem-resistant Enterobacteriaceae is critical for preventing the spread of these organisms and improving patient outcomes 2, 6.
- Delays in diagnosis and treatment can lead to increased mortality rates and hospital costs, making rapid detection methods a priority 6.
- The development of rapid and affordable detection techniques, such as real-time PCR, is essential for controlling the spread of carbapenem resistance and improving patient outcomes 6.