Sanitary Waters: Is It Worth Looking for Mycobacteria?

Area of Science:

• Environmental microbiology
• Clinical microbiology
• Genomics

Background:

• Freshwater environments support nontuberculous mycobacteria (NTMs) growth.
• NTMs pose a risk to sanitary water systems, acting as potential transmission vectors.
• Hospital water systems are critical areas for investigating NTM occurrence.

Purpose of the Study:

• To investigate the presence of NTMs, specifically Mycobacterium saskatchewanense, in hospital water systems.
• To support surveillance and control strategies for potentially pathogenic NTMs.
• To analyze the genetic variability of M. saskatchewanense strains found in dialysis fluid.

Main Methods:

• Analysis of 722 ultrapure dialysis fluid samples from Emilia Romagna Dialysis Services.
• Identification and isolation of Mycobacterium saskatchewanense.
• Whole-genome sequencing (WGS) for strain characterization and variability analysis.

Main Results:

• 35 out of 722 samples tested positive for M. saskatchewanense.
• Exclusive presence of M. saskatchewanense was detected in the analyzed dialysis machines.
• Low genetic variability (<15 different alleles) was observed among all M. saskatchewanense strains.
• WGS-based ML tree analysis confirmed strong similarity among strains with no distinct clusters.

Conclusions:

• The study highlights the presence and genetic homogeneity of M. saskatchewanense in hospital dialysis systems.
• There is a critical need for enhanced surveillance protocols for NTMs in healthcare settings.
• Investigating potential links to human infections and improving infection control measures are urgent priorities.