Bacteria and associated antibiotic resistance in air filter-derived biological material from utility vehicles at mechanical-biological treatment plants.

Abstract

Objectives: The study objective was to assess occupational exposure to bacteria and antimicrobial resistance genes (ARGs) present on air filters of utility vehicles used in the working environment of mechanical-biological treatment (MBT) facilities, in the context of workers health risks.

Material and methods: The study was conducted in summer 2024 in 9 air filters from utility vehicles used in MBT plants in Poland. External filters were removed from the vehicle's ventilation system, packed and shipped according to instructions. From the duplicate filters samples DNA was isolated and high-throughput next-generation sequencing (NGS) was carried out. Bioinformatic data analysis was conducted to detect bacteria and ARGs in air filters' surfaces.

Results: Totally, 34 bacterial taxa were detected in relative abundance ≥0.5%. The genera most frequently present at the highest relative abundances: Saccharomonospora, Thermobifida, Nocardiopsis, Pectobacterium, Aerococcus, Thermoactinomyces, Novibacillus and Streptomyces. Across all bacteria isolated from the analyzed filters, regardless of their relative abundance, a total of 91 taxa were classified into risk groups 2 or 3 (86 and 5 taxa, respectively). The most frequently detected ARGs were those encoding resistance to a single class of antibiotics (AAC(3)-VIIa, aadA2, ANT(6)-Ia, APH(3'')-Ia, APH(3'')-Ib, APH(6)-Id, cml, cmx, lnuA, lnuD, novA, parY, sul2, vanHF, vanJ, vanRA, vanRI, vanRO - each at least on 4 air filters). Antimicrobial resistance genes encoding multi antibiotic resistance were also detected: CRP, emtA, erm(34), erm(36), ermA, ermC, ermF, ermG, ermT, ermX, ernB, H-NS, mel, msrA, msrE, mtrA, optrA, ramA, ykkD - each at least on 1 air filter.

Conclusions: Despite the limited number of analyzed filters, the study demonstrated a high bacterial species diversity in the MBT plant environment. The MBT workers are exposed to bacteria with high pathogenic potential and to ARGs encoding resistance to antibiotics used exclusively in human medicine, used in human and veterinary medicine, and not intended for human use. Int J Occup Med Environ Health. 2026;39(2):179-201.