Study co-author Mark Merchant, a biochemist at McNeese State University in Lake Charles, Louisiana, was among the first to notice alligators’ unusual resistance. He was intrigued that, despite living in swampy environments where bacteria thrive, alligators that suffered frequent scratches and bruises rarely developed fatal infections. Merchant therefore created human and alligator serum-protein-rich blood plasma that has been able to remove clotting agents, and exposed each of them to 23 strains of bacteria.
The word ’bruises’ in the paragraph is closest in meaning to ....