# Antibiotic Resistance in the Farming Environment
## 6 Environmental Emissions and Human Health Risks  
Farm workers are an occupational group that, due to the nature of their work, can be particularly exposed to antibiotic-resistant microflora [21]. [PERSON] et al. [39] estimated that inhalation intake of antibiotic-resistant bacteria potentially pathogenic to humans for pig farm workers can be up to three times higher than for hospital employees. An important role in the spread of antibiotic resistance in the farming environment is played by the air dust route, droplet dust route, direct skin contact, and to some extent the oral route [37; 100]. Systematic contact with farm animals can contribute to the spread of drug-resistant microorganisms via direct transmission [25]. [PERSON] et al. [85] noted the fact of the evolution of antibiotic-resistant bacteria and their adaptation to new environments and organisms of new hosts. A strain of methicillin-resistant _Staphylococcus aureus_ isolated in Finland was not only detected in livestock--pigs, cattle, and poultry--in subsequent years but the possibility of its transmission to humans was also found [101]. There are data supporting the possibility of similar and even the same resistant strains of _E. coli_ and _Enterococcus_ spp. in livestock, in samples collected on farms, and in farm workers [102; 103; 104; 51]. Antibiotic-resistant ESBL-producing _E. coli_ strains were found in more than 70% of healthy animal farm workers in Thailand and were also reported in 76.7% of pigs and over 40% of poultry broilers [105]. It was observed that the mcr-1 gene that determines resistance to colistin, one of the important antibiotics in human therapy was present in _E. coli_ isolated from both pigs and farmers [106]. Pig farm workers have also been reported to have elevated antibiotic resistance genes in the nasopharyngeal microbiota [107]. Moreover, some similarities were found between the microbiome of the nasal or nasopharyngeal cavity of pig farmers and microorganisms present in the farm air [108]. [PERSON] et al. [109] studied the occurrence of antibiotic resistance genes in poultry, in the air of poultry housing, and in samples from the nasopharynx of farm workers in China, and found some similarities in the distribution and structure of the environments studied in terms of antibiotic resistance genes. It confirms that the transmission of antibiotic-resistant bacteria from animals to humans can also occur indirectly--as a result of contamination with resistant microorganisms in the air around livestock facilities and in surface water and soil. [PERSON] et al. [110] tested for antibiotic resistance strains of _E. coli_ isolated from the air and leachate from the grounds of and around a cattle farm in Spain. The authors found that of the isolated strains, nearly 22% showed resistance traits to antibiotics such as tetracycline, ampicillin, and trimethoprim/sulfamethoxazole, among others. Single strains were resistant to chloramphenicol and gentamicin-tobramycin. Among the antibiotic resistance genes identified were blaTEM-1, tet(A), tet(B), cmLA, flor, sul1, sul2, sul3. About 14% of the strains showed features of multi-resistance. [PERSON] et al. [63] isolated antibiotic-resistant strains of _E. coli_ and bacteria of the genera _Staphylococcus_ and _Salmonella_ from the samples related to poultry farming, including litter, exhaust air samples, and nearby surface waters and groundwater. The role of air as a pathway for the spread of antibiotic-resistant agents in the agricultural work environment has been also pointed out by [PERSON] et al. [111], [PERSON] et al. [112], [PERSON] et al. [80], and [PERSON] et al. [39]. It was observed that the air microflora on pig farms was characterized by resistance to tetracyclines, imcosamides, and aminoglycos, with the presence of antibiotic resistance genes detected in potentially pathogenic strains of the genera _Clostridium_, _Streptococcus_, and _Aerococcus_, among others [39].