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ORIGINAL RESEARCH article

Front. Microbiol.
Sec. Infectious Agents and Disease
Volume 15 - 2024 | doi: 10.3389/fmicb.2024.1492360

Use of BD BACTEC™ MGIT™ for the detection of nontuberculous mycobacteria in sanitary water samples

Provisionally accepted
Vincenzo Ferraro Vincenzo Ferraro 1,2Francesco Bisognin Francesco Bisognin 1,2*Federica Sorella Federica Sorella 1,2Federica Ruin Federica Ruin 1,2Paola Dal Monte Paola Dal Monte 2,3
  • 1 Department of Medical and Surgical Sciences, University of Bologna, Bologna, Emilia-Romagna, Italy
  • 2 Microbiology Unit, IRCCS Azienda Ospedaliero-Universitaria of Bologna, Bologna, Italy
  • 3 Department of Experimental, Diagnostic and Specialty Medicine, University of Bologna, Bologna, Italy

The final, formatted version of the article will be published soon.

    The most commonly used method for the detection of nontuberculous mycobacteria (NTM) is culture in BD BACTEC™ MGIT™ Mycobacteria Growth Indicator Tubes incubated in an automated growth detection reader BD BACTEC™ MGIT™ 960 Instrument. The system is currently validated for the detection of mycobacteria from clinical specimens but not environmental matrices. From November 2018 to December 2023, 1369 sanitary water samples from 92 Heater Cooler Units (HCU) and 747 sanitary water samples from 489 Haemodialysis instruments (Dialysis) were concentrated, decontaminated, and cultured on MGIT and solid Lowenstein-Jensen media to evaluate the presence of NTM. NTM positive cultures (n = 261 HCUs and n= 20 dialysis) were purified by Middlebrook 7H11 agar plate subcultures and identify by MALDI-TOF mass spectrometry technology . The purpose of this study is to evaluate the accuracy and reproducibility of the MGIT system on sanitary water from HCU and Dialysis, using as sources of NTM the two strains most frequently isolated on these devices during Emilia-Romagna surveillance programme: M. chimaera (79%) and M. saskatchewanense (100%), respectively. To evaluate accuracy, sanitary water were spiked with M. chimaera and M. saskatchewanense at the theoretical concentration of 100 and 10 CFU/ml, and all resulted positive in MGIT tube. No significant changes in Time to Positivity were observed when MGIT tubes was inoculated with NTM at the theoretical concentration of 10 and 100 CFU/ml on 3 consecutive days, indicating that detection method is reproducible. The MGIT system is suitable to detect the presence of NTM in sanitary water samples, as it was capable of detecting up to 4 CFU/ml for both M. chimaera and M. saskatchewanense. Our results indicate that MGIT system can be used for NTM detection not only for clinical samples, but also environmental matrices.

    Keywords: Nontuberculous Mycobacteria, NTM, M. chimaera, M. saskatchewanense, Sanitary water, BD BACTEC MGIT Mycobacteria Growth Indicator Tubes

    Received: 06 Sep 2024; Accepted: 14 Oct 2024.

    Copyright: © 2024 Ferraro, Bisognin, Sorella, Ruin and Dal Monte. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

    * Correspondence: Francesco Bisognin, Department of Medical and Surgical Sciences, University of Bologna, Bologna, 40126, Emilia-Romagna, Italy

    Disclaimer: All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.