Multiplex PCR scheme for variant plasmid mediated class C β-lactamase typing.

Background: An increasing of prevalence and diversification of plasmid-mediated AmpC (pAmpC) has been emerged worldwide. The incidence of pAmpC resulted in increasing β-lactamase production and conferred resistance to almost all β-lactam antibiotics excluding carbapenems. The lack of standard method for pAmpC identification and classification exert a challenge in epidemiological surveillance and infection control practices.

Methods: A robust, single tube multiplex PCR has been developed to classify six different pAmpC groups including CIT (CMY-2 like, LAT and CFE), ECB (ACT, MIR), MOX & CMY-1 like, DHA, ACC, and FOX. The developed method was optimized and validated by testing of sensitivity and specificity.

Results: Developed method can detect crude extracted DNA template at nano-scale (2.5 ηg) and has high discriminatory power as compared to phenotypic and commercial genotypic method.

Conclusion: The developed method can be utilized for tracking the changes of clinically important resistance patterns and further investigation of occurrence and distribution of plasmid-mediated AmpC types.