Environmental superbugs: The case study of Pedobacter spp.

Area of Science:

• Environmental microbiology
• Antimicrobial resistance
• Genomics

Background:

• Antibiotic resistance genes (ARGs) are prevalent in environmental reservoirs.
• Multidrug-resistant (MDR) environmental isolates are understudied.
• Pedobacter species are found in various environments, including soil and water.

Purpose of the Study:

• To investigate the antibiotic susceptibility of Pedobacter lusitanus NL19 and related species.
• To characterize the antibiotic resistance genes and mechanisms in Pedobacter spp.
• To assess the potential of Pedobacter spp. as environmental reservoirs of ARGs.

Main Methods:

• Phenotypic antibiotic susceptibility testing of Pedobacter strains.
• Whole-genome sequencing and analysis of Pedobacter isolates.
• Characterization of specific beta-lactamase enzymes (LUS-1 and PLN-1) in E. coli.

Main Results:

• All investigated Pedobacter strains exhibited multidrug resistance (MDR) to beta-lactams, colistin, aminoglycosides, and ciprofloxacin.
• Pedobacter spp. likely possess intrinsic resistance to beta-lactams, including ertapenem.
• 6%-8% of Pedobacter genes encode diverse ARGs, including highly abundant beta-lactamases (Class C, B3, A).
• PLN-1, a Class B3 beta-lactamase, demonstrated carbapenemase activity, conferring resistance to ertapenem, imipenem, and meropenem.

Conclusions:

• Pedobacter species harbor a significant and diverse array of antibiotic resistance mechanisms.
• These bacteria represent potential environmental superbugs due to their extensive resistance profiles.
• Understanding Pedobacter's role in ARG dissemination is crucial for environmental antibiotic resistance surveillance.