P51
Integrated Analysis of Mycobacterium chimaera strains isolated from contaminated heater-cooler units using Fourier Transform Infrared (FTIR) Spectroscopy and Whole Genome Sequencing
F Bisognin(1) F Messina(2) O Butera(2) C Nisii(2) A Mazzarelli(2) S Cristino(3) M R Pascale(3) G Lombardi(1) A Cannas(2) P Dal Monte(1)
1:IRCSS, Azienda Ospedaliero-Universitaria di Bologna; 2:National Institute for Infectious Diseases "L. Spallanzani", IRCCS, Rome, Italy; 3:BiGeA, Alma Mater Studiorum - Università di Bologna
Mycobacterium chimaera is ubiquitously widespread in the environment, including factories and hospitals water systems. Recently, invasive cases of M. chimaera have been associated with the aerosol produced by the use of Heater-Cooler Units (HCU) during cardiac surgery. This study is part of the regional surveillance for the research of M. chimera in water from HCU devices.
The goal of this study is to evaluate the performance of Fourier transform infrared spectroscopy (FTIRS) for subtyping of M. chimaera, comparing with Whole Genome Sequencing (WGS) analysis. The study was carried out on a high number of M. chimaera isolates coming from longitudinal environmental HCUs and water sources, sampling from three different hospitals.
From November 2018 to May 2021, 440 waters were concentrated, decontaminated and cultured for M. chimaera. Positive cultures (n= 54) were purified by plate subcultures and typed by IR-Biotyper® and WGS (Ion Torrent sequencing system).
IR-Biotyper® generated 3 different clusters: 21/21 M chimaera isolates belonging to hospital A fell in cluster n.1, 28/28 belonging to hospital M in cluster n. 2 and 5/5 from hospital S fell in cluster n. 3. According to WGS analysis 19/21 strains from Hospital A were classified as 1.1 subgroup, 1/21 as ungrouped and 1/21 as 2.1 subgroup. 5/5 strains from Hospital S were classified as 1.1; 23/28 strains from Hospital M were classified as Branch 2 and 5/28 as ungrouped.
An integrated use of WGS and IR Biotyper could be useful to investigate possible instruments contaminations, as they returned similar phylogenetic results.