[Rapid identification of ESBL--positive clinical samples using real-time PCR method]

Area of Science:

• Clinical microbiology
• Molecular diagnostics
• Infectious diseases

Background:

• Extended-spectrum beta-lactamase (ESBL) production in Enterobacteriaceae is a growing public health concern.
• Rapid detection of ESBL-producing bacteria is crucial for effective patient management and infection control.

Purpose of the Study:

• To develop and evaluate a novel real-time PCR method for direct detection of ESBL genes (blaCTX-M and blaSHV) in clinical specimens.
• To compare the performance of the real-time PCR assay with standard microbiological culture methods.

Main Methods:

• Real-time PCR using locked nucleic acid oligonucleotides was employed to detect blaCTX-M and blaSHV genes.
• Tracheal aspirates from mechanically ventilated patients were analyzed.
• Samples were also subjected to standard microbiological culture for phenotypic ESBL determination.

Main Results:

• The real-time PCR method identified 18% (27/150) of samples as ESBL-positive, compared to 8.7% (13/150) by culture.
• The blaCTX-M gene was detected in 24 samples, blaSHV in 2, and both genes in 1 sample.
• All culture-positive samples were also positive by real-time PCR.

Conclusions:

• The developed real-time PCR assay offers a significantly faster method for detecting ESBL-producing Enterobacteriaceae, reducing detection time from 48 to 6 hours.
• This rapid diagnostic capability is vital for timely antimicrobial therapy in patients with severe nosocomial pneumonia.