https://phys.org/news/2018-07-hidden-hazards-antibiotic-resistance-genes.html

The team performed a survey of 30 ARGs across 19 cities around the world, including San Francisco, Beijing and Paris. The group studied ARGs resistant to seven common classes of antibiotics: quinolones, β-lactams, macrolides, tetracyclines, sulfonamides, aminoglycosides and vancomycins. Beijing had the most diverse group of airborne ARGs, with 18 different subtypes detected, while San Francisco had the highest overall level of airborne ARGs. Genes resistant to β-lactams and quinolones were the two most abundant types of ARGs in all the cities studied. Low levels of ARGs resistant to vancomycin, an antibiotic of last resort for MRSA treatment, were found in the air of six cities.

                                                            
                                    
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                                    Scientists map the distribution of antimicrobial resistance across Chinese major cities

Global Survey of Antibiotic Resistance Genes in AirEnvironmental Science & Technology (2018). pubs.acs.org/doi/abs/10.1021/acs.est.8b02204