CCL2 and infection: Significant difference in MCP-1 expression between 24 and 48 hr post-infection was detected in response to all Mtb strains (sensitive [rank of difference: -1.55; P=0.008]; INHR [rank of difference: -1.3; P=0.006]; MDR [rank of difference: -0.97; P=0.01]; XDR [rank of difference: -1.8; P=0.008]) other than RifR [rank of difference: -0.54; P=0.05].