title: Morphine increases susceptibility to oral Salmonella typhimurium infection.
abstract: This study examined the effect of morphine on oral infection with virulent Salmonella typhimurium. Animals were treated with a 75-mg slow-release morphine pellet followed by inoculation with salmonellae. Morphine markedly sensitized mice to oral infection, as assessed by survival, mean survival time, and colony culture. By 24 h after Salmonella inoculation, morphine-treated mice had a 105-fold difference in number of organisms in the Peyer's patches, compared with controls. The opioid antagonist naltrexone significantly blocked Salmonella colonization in Peyer's patches and reduced Salmonella burden in other organs, indicating that morphine acts at least in part via an opioid receptor-mediated pathway. The data show that morphine markedly potentiates Salmonella infection at the gastrointestinal portal of entry and enhances subsequent dissemination of Salmonella organisms. The results have implications for potentiating gastrointestinal opportunistic infections in intravenous drug abusers and in opioid-medicated postsurgical patients.
authors.affiliation: Departments of Microbiology and Immunology, Temple University School of Medicine, Philadelphia, PA 19140, USA.
authors.forename: A S
authors.initials: AS
authors.lastname: MacFarlane
authors.forename: X
authors.initials: X
authors.lastname: Peng
authors.forename: J J
authors.initials: JJ
authors.lastname: Meissler
authors.forename: T J
authors.initials: TJ
authors.lastname: Rogers
authors.forename: E B
authors.initials: EB
authors.lastname: Geller
authors.forename: M W
authors.initials: MW
authors.lastname: Adler
authors.forename: T K
authors.initials: TK
authors.lastname: Eisenstein
mesh_terms: D000818:Animals; D016207:Cytokines / Q000096:biosynthesis / Q000235:genetics; D004198:Disease Susceptibility; D005260:Female; D005856:Germ-Free Life; D051379:Mice; D008809:Mice, Inbred C3H; D009020:Morphine / Q000494:pharmacology*; D009055:Mouth / Q000382:microbiology; D009059:Mouth Diseases / Q000209:etiology / Q000382:microbiology*; D009271:Naltrexone / Q000494:pharmacology; D019001:Nitric Oxide Synthase / Q000096:biosynthesis / Q000235:genetics; D052247:Nitric Oxide Synthase Type II; D010581:Peyer's Patches / Q000382:microbiology; D012333:RNA, Messenger / Q000096:biosynthesis; D012481:Salmonella Infections, Animal / Q000209:etiology*; D012486:Salmonella typhimurium
chemical_list: D016207:Cytokines; D012333:RNA, Messenger; D009271:Naltrexone; D009020:Morphine; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; C496317:Nos2 protein, mouse