Detection of bla KPC and bla NDM genes by duplex PCR with lateral flow dipsticks from sterile body fluid samples.

Duplex polymerase chain reaction with lateral flow dipsticks (duplex PCR-LFD) was developed for the simultaneous detection of beta-lactamase Klebsiella pneumoniae carbapenemase (bla _KPC ) and beta-lactamase New Dehli metallo-beta-lactamase (bla _NDM ) genes in body fluid samples. This method was validated using well-characterized isolates. The assessment of the specificity of duplex PCR-LFD showed that there was no cross-reactivity with other targets. The detection limit of the duplex PCR-LFD assay was 20 CFU per ml for bla _KPC and bla _NDM . Among 177 sterile body fluid samples tested by the duplex PCR-LFD assay, 40 were bla _KPC -positive and five were bla _NDM -positive. The results obtained from 122 corresponding Gram-negative bacteria which were isolated from these clinical samples and tested by duplex PCR-LFD assay showed that there were 37 strains carrying bla _KPC genes in 40 bla _KPC -positive samples and three strains carrying bla _NDM genes in five bla _NDM -positive samples. Statistical analysis indicated that there was no significant difference between the direct detection of bla _KPC and bla _NDM genes in clinical sterile body fluid samples and their corresponding clinical isolates. Therefore, duplex PCR-LFD can be effective for the simultaneous detection of bla _KPC and bla _NDM in clinical isolates and directly from clinical samples, which may be helpful for the administration of appropriate antimicrobial treatment.
(© 2021 The Society for Applied Microbiology.)