# Antibiotic Resistance in the Farming Environment
## 6 Environmental Emissions and Human Health Risks
The inhalation route is one route of exposure of farm workers to potentially pathogenic multi-resistant strains of the genus _Staphylococcus_[37]. It has been observed that not only direct contact but also the airborne route is responsible for the transmission of \(\beta\)-lactamase-encoding genes from animals to farm workers [51]. For example, the \(\beta\)-lactam resistance gene blaTEM, quinolone resistance gene qepA, and gene blaNDM-1 conferring resistance to carbapenem can be transported through the air [113]. Based on the air contamination assessment and atmospheric dispersion modeling, [PERSON] et al. [37] found the possibility of spreading drug resistance genes from o area poultry and dairy farms by air over a distance of 10 km along the wind direction. Among the detected airborne bacteria containing antibiotic resistance genes, potentially pathogenic microorganisms were found, including those of the genera _Staphylococcus_, _Sphingomonas_, and _Acinetobacter_. It was further found that all isolated strains from poultry farms were characterized by multi-resistance (to more than three antibiotics), while 80% of them carried the methicillin resistance gene (mecA) [37]. It has been confirmed that one pathway for the spread of antibiotic-resistant bacteria may be farm dust [108]. Analysis of the microflora of pig and poultry farm dust for antibiotic resistance factors showed that farm dust had a greater diversity of genes responsible for antibiotic resistance than the intestinal microflora of farm animals [108]. This observation is important because it is the bacteria present in the dust that can easily spread through the air and travel even long distances from the farm site. When bioaerosol concentrations are high, the likelihood of transfer of antibiotic-resistant agents increases, including toward pathogenic microorganisms [39]. Studies have shown the possibility of spreading antibiotic resistance factors along with dispersed dust from large-scale beef cattle feed yards. It was found that the concentration of genes determining tetracycline resistance was significantly higher in dust samples collected downwind of feed yards compared to samples collected upwind [111]. The presence of antibiotic residues in farm dust accumulating in breeding facilities can be an important selection factor for bacteria present in the dust. [PERSON] et al. [114] conducted a study of dust samples collected over a 20-year period from the same pig breeding facilities and found residues of antibiotics such as tetracycline, chloramphenicol, sulfamethazine, and tylosin in amounts as high as 12.5 mg/kg of the dust. Leachates from waste lagoons and manure pits can be a source of contamination of surface and groundwater with resistant bacteria [30]. It has been found that close proximity to pig farms can result in elevated concentrations of both antibiotics and antibiotic resistance factors (bacteria, resistance genes) in groundwater [115]. [PERSON] et al. [116] found widespread occurrence of sul1 and sul2 genes in sediments from rivers into which animal farming wastewater was discharged. It is also worth mentioning an additional pathway for the spread of antibiotic-resistant microorganisms in the farming environment, which is various types of insects-houseflies, stable flies, and cockroaches, serving as vectors of microorganisms, primarily of fecal origin [18]. Studies conducted on cattle farms have shown that flies were vectors for multi-resistant _E. coli_ O157:H7 and EBL-producing _E. coli_[117; 118]. The pathways for the spread of antibiotic resistance agents in the agricultural work environment, including their transfer to humans are summarized in Figure 4.