Some strains of gonorrhoea ( Neisseria gonorrhoeae ; orange) are resistant to several antibiotics. Credit: Science Photo Library Global map of resistance genes in livestock manure reveals their risk to human health Livestock farming relies heavily on antibiotics, and manure contains drug-resistant bacteria that can infect people . A study led by researchers at China’s Northwest A&F University in Shaanxi mapped the global patterns of livestock-associated antibiotic-resistance genes that threaten human health. Nature Outlook: Antimicrobial resistance The scientists analysed more than 4,000 samples of manure from pigs, chickens and cattle in 26 countries over 14 years. They found more than 3,000 uncharacterized antibiotic-resistance genes, showing that manure hosts a more diverse set of resistant bacteria than was thought. To assess the potential impact on human health, the researchers calculated each gene’s likelihood of affecting how well antibiotics worked.…