title: Association of multicellular behaviour and drug resistance in Salmonella enterica serovars isolated from animals and humans in Ethiopia.
abstract: OBJECTIVE
  To determine the association between multicellular behaviour, integron status and antibiotic resistance among 87 Ethiopian Salmonella enterica isolates of animal and human origin.
  
  
  RESULTS
  Isolates were characterized for their biofilm forming ability, antimicrobial susceptibility and the presence and characteristics of a class 1 integron and Salmonella genomic island 1 (SGI1). The majority of isolates grown at environmental temperatures (20°C) exhibited robust biofilm formation (72·4%) and displayed RDAR colony morphology on Congo red agar plates. The presence of a class 1 integron correlated with the extent of drug resistance and ability to exhibit multicellular behaviour.
  
  
  CONCLUSIONS
  Although cellulose production and RDAR morphology correlated with increased multicellular behaviour, neither was required for biofilm formation. Contrary to previous reports, colony morphology was generally consistent within a serovar. No integrons were detected in isolates deficient for multicellular behaviour, indicating a potential role of bacterial community formation in transfer of genetic elements among environmental isolates.
  
  
  CONCLUSIONS
  Infection by Salm. enterica is a major public health problem worldwide. The dominance of multidrug resistance and multicellular behaviour in Salmonella isolates of Ethiopian origin highlights a need for integrated surveillance and further detailed phenotypic and molecular studies of isolates from this region.
authors.affiliation: Aklilu Lemma Institute of Pathobiology, Addis Ababa University, P.O. Box 1176, Addis Ababa, Ethiopia.
authors.forename: Tadesse
authors.initials: T
authors.lastname: Eguale
authors.affiliation: Department of Microbial Infection and Immunity, Center for Microbial Interface Biology, The Ohio State University, Biomedical Research Tower, 460 West 12th, Columbus, OH 43210-1214.
authors.forename: Joanna
authors.initials: J
authors.lastname: Marshall
authors.affiliation: Department of Veterinary Preventive Medicine, The Ohio State University, 1920 Coffey Rd., Columbus, Ohio 43210.
authors.forename: Bayleyegn
authors.initials: B
authors.lastname: Molla
authors.affiliation: Department of Microbial Infection and Immunity, Center for Microbial Interface Biology, The Ohio State University, Biomedical Research Tower, 460 West 12th, Columbus, OH 43210-1214.
authors.forename: Aditi
authors.initials: A
authors.lastname: Bhatiya
authors.affiliation: Department of Veterinary Preventive Medicine, The Ohio State University, 1920 Coffey Rd., Columbus, Ohio 43210.
authors.forename: Wondwossen A
authors.initials: WA
authors.lastname: Gebreyes
authors.affiliation: Department of Pharmacology School of Pharmacy, College of Health Sciences, Addis Ababa University, Churchill Avenue, P.O. Box 1176, Addis Ababa, Ethiopia.
authors.forename: Ephrem
authors.initials: E
authors.lastname: Engidawork
authors.affiliation: Department of Microbiology, Immunology & Parasitology, School of Medicine, College of Health Sciences, Addis Ababa University, Churchill Avenue, P.O. Box 9086, Addis Ababa, Ethiopia.
authors.forename: Daniel
authors.initials: D
authors.lastname: Asrat
authors.affiliation: Department of Microbial Infection and Immunity, Center for Microbial Interface Biology, The Ohio State University, Biomedical Research Tower, 460 West 12th, Columbus, OH 43210-1214.
authors.forename: John S
authors.initials: JS
authors.lastname: Gunn
mesh_terms: D000818:Animals; D018441:Biofilms / Q000254:growth & development; D002482:Cellulose / Q000378:metabolism; D024901:Drug Resistance, Multiple, Bacterial / Q000235:genetics; D005002:Ethiopia; D044404:Genomic Islands; D006801:Humans; D032023:Integrons / Q000235:genetics; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D012480:Salmonella Infections / Q000382:microbiology*; D012481:Salmonella Infections, Animal / Q000382:microbiology*; D019779:Salmonella enterica / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification* / Q000502:physiology
chemical_list: D002482:Cellulose
keywords: Ethiopia; Salmonella; antimicrobials; biofilms; integron