Detecting bacteria contamination on medical device surfaces using an integrated fiber-optic mid-infrared spectroscopy sensing method

Abstract

Bacterial contamination on medical device surfaces is a critical public health concern. In order to detect bacteria on medical device surface, alternative methods for quantitative, accurate, easy-to-use, and real-time detection and identification of microorganism contamination are needed. We have recently presented a novel proof-of-concept platform for non-contact, label-free and real-time detection of surface contamination employing a fiber-optic Fourier transform infrared (FO-FTIR) spectroscopy sensing methodology in the mid-infrared (mid-IR) spectral range of 1.6–12μm. In the present study, we demonstrate the detection capability and sensitivity of the integrated FO-FTIR approach using four species of commonly encountered bacteria: Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa and Streptococcus pneumoniae. FO-FTIR combined with multivariate approaches such as hierarchical clustering and principal component analysis provided specific mid-IR spectral differentiation of the four microorganisms including when the sample contained mixtures of bacteria types. To assess the sensitivity of the FO-FTIR platform, bacteria samples were prepared at 109 colony forming unit (CFU)/μL and then serially diluted 1:10 eight times. The salient findings of this investigation showed that the integrated FO-FTIR based sensor can detect the presence of the bacteria at concentrations between 103 and 104CFU/2μL, producing unique bacteria signatures with high reproducibility. The advanced features of this sensing method in terms of sensitivity, specificity and repeatability employing non-contact, label-free, and real-time approaches, demonstrate its potential use as an alternative effective screening tool for routine monitoring of bacterial contaminated surfaces.