Investigating the Origin of Mycobacterium chimaera Contamination in Heater-Cooler Units: Integrated Analysis with Fourier Transform Infrared Spectroscopy and Whole-Genome Sequencing

• DOI: 10.1128/spectrum.02893-22
• Publication Date: 2022-10-12T14:02:39Z
• Authors: F. Bisognin; F. Messina; O. Butera; C. Nisii; A. Mazzarelli; S. Cristino; M. R. Pascale; G. Lombardi; A. Cannas; P. Dal Monte
• Keywords: Chimera (genetics)

Mycobacterium chimaera is ubiquitously spread in the environment, including factory and hospital water systems. Invasive cases of M. infection have been associated with aerosols produced by use heater-cooler units (HCU) during cardiac surgery. The aim this study was to evaluate for first time performance IR-Biotyper system on a large number isolates collected from longitudinal environmental HCUs samples sources hospitals located three Italian provinces. In addition, results were compared whole-genome sequencing (WGS) analysis, reference method molecular epidemiology, investigate origin contamination HCUs. From November 2018 May 2021, 417 52 (Stockert 3T, n = 41 HCU40, 11) 23 taps (used fill HCU tanks) concentrated, decontaminated, cultured chimaera. Positive cultures (n 53) purified agar plate subcultures analyzed platform Ion Torrent system. spectra using statistical approach dimensionality reduction linear discriminant analysis (LDA), generating separate clusters chimaera, ascribable each hospital. Furthermore, only chimaera-positive sample tap clustered same hospital, confirming that plumbing could represent source and, potentially, patient infection. According genome-based phylogenies following classification proposed van Ingen collaborators 2017, distinct groups appear contaminated systems: subgroups 1.1, 2.1, branch 2. Most strains isolated at share highly similar genetic profile. nonrandom distribution obtained WGS leads hypothesis subtypes circulating local colonize through absolute filter, addition current occurs production site. This opens possibility other medical equipment, such as endoscope reprocessing device or hemodialysis systems, be IMPORTANCE Our manuscript focuses interventions reduce waterborne disease transmission, improve sanitation, control Sanitary can nontuberculous Mycobacteria, causative agent invasive infections immunocompromised patients. We found phenotypic profiles used surgery thermo-regulate patients' body temperature, water. These lead adding equipment sanitized water, devices suggesting need surveillance measures.