Reduction of the Carbapenemase Inactivation Method (CIM) assay time by real-time PCR

Area of Science:

• Microbiology
• Molecular Biology
• Clinical Diagnostics

Background:

• Carbapenemase-producing Gram-negative bacteria pose a significant public health threat.
• The Carbapenemase Inactivation Method (CIM) is a phenotypic test to detect carbapenemase production.
• Traditional CIM requires 6-24 hours for meropenem inactivation assessment.

Purpose of the Study:

• To develop a rapid and accurate method for detecting carbapenemase production in Gram-negative bacteria.
• To reduce the turnaround time for carbapenemase detection compared to the conventional CIM.
• To validate a nucleic acid testing approach for carbapenemase detection.

Main Methods:

• Modification of the Carbapenemase Inactivation Method (CIM).
• Utilizing real-time PCR to measure the growth of the E. coli indicator strain ATCC 25922.
• Development of a nucleic acid testing CIM (natCIM).

Main Results:

• The natCIM significantly reduces the detection time for carbapenemase production.
• Detection time was decreased from 6-24 hours to approximately 4 hours.
• The natCIM provides a faster alternative for identifying carbapenemase-producing Gram-negative bacteria.

Conclusions:

• The nucleic acid testing CIM (natCIM) is a rapid and effective method for detecting carbapenemase.
• natCIM offers a substantial time advantage over the traditional CIM.
• This rapid detection method can aid in timely clinical decisions and infection control.