Triple-metal organic framework-based colorimetric aptasensor with aptamer-enhanced nanozyme activity for ultrasensitive detection of multidrug-resistant bacteria

Infections with multidrug-resistant bacteria (MDRB) result in high morbidity and mortality. Among the various methods currently used to detect MDRB, culture-based methods are reliable but usually time-consuming and laborious, and polymerase chain reaction is expensive or cumbersome to perform, making it difficult to meet detection needs. In this work, we developed an accurate, efficient, and convenient colorimetric aptasensor for the detection of MDRB through aptamer-mediated enhancement of FeCoMn-MOF-74 peroxidase mimetic activity. Using New Delhi metallo-β-lactamase-1 Klebsiella pneumoniae (NDM-1 KP) and Klebsiella pneumoniae carbapenemase 2 Escherichia coli (KPC-2 E. coli ) as models, the proposed colorimetric aptasensor demonstrated a wide linear range (10–10 8  CFU/mL for both) and low detection limits (7 and 9 CFU/mL for NDM-1 KP and KPC-2 E. coli, respectively) under optimized conditions. In addition, the aptasensor exhibited high specificity, excellent immunity to interference, and high stability. The utility of the constructed aptasensor was verified by spiking the assay in serum, peritoneal fluid, and cerebrospinal fluid with satisfactory recoveries, which not only confirmed the clinical utility of the aptasensor in contaminated specimens, but also revealed the capacity of FeCoMn-MOF-74 as a generalized biosensing platform for sensitive detection of other MDRB.