title: Serratia marcescens resistance profile and its susceptibility to photodynamic antimicrobial chemotherapy.
abstract: BACKGROUND
  Some authors have reported the antimicrobial action of photodynamic antimicrobial chemotherapy (PACT) on bacteria related to nosocomial infections but there are few studies evaluating PACT on Serratia marcescens grown as planktonic cultures or as biofilms. The purpose of this study was to analyze the S. marcescens resistance profile and its susceptibility to PACT.
  
  
  METHODS
  Initially, 55 S. marcescens strains isolated from environmental, oral and extra-oral infections were tested by antimicrobial resistance to cefotaxime (CTX), imipenem (IPM), ciprofloxacin (CIP), tobramycin (TOB) and doxycycline (DOX) using E-test(®). Following, isolates grown as planktonic cultures or biofilms were submitted to PACT using the association of a light-emitting diode and toluidine blue (TBO). The E-test(®) results demonstrated intermediated sensitive strains to CTX, IMP, TOB, and DOX; and resistant strains to CTX, TOB, DOX and CIP. Also, CTX and IMP demonstrated variation when CLSI 2007 and CLSI 2015 were compared.
  
  
  RESULTS
  Planktonic cultures and biofilms submitted to PACT demonstrated counts varying from 10(11) to 10(7) for planktonic cultures and 10(10) to 10(7) for biofilms. There were no statistical differences in the results when planktonic cultures and biofilms were compared.
  
  
  CONCLUSIONS
  Increase in the profile of S. marcescens resistance was observed when CLSI 2007 and CLSI 2015 were compared. Also, IMP remains as the drug with lower rate of resistance. Additionally, both S. marcescens planktonic cultures and early biofilms are susceptible to PACT under tested conditions.
authors.affiliation: Biotechnology Post-Graduate Program, Federal University of Ceara, Comandante Mauricélio, Rocha Pontes Street, 100, Sobral, CE 62.042-280 Brazil.
authors.forename: Ticiana Mont Alverne Lopes
authors.initials: TM
authors.lastname: Parente
authors.affiliation: Biotechnology Post-Graduate Program, Federal University of Ceara, Comandante Mauricélio, Rocha Pontes Street, 100, Sobral, CE 62.042-280 Brazil.
authors.forename: Emanuela de Lima
authors.initials: Ede L
authors.lastname: Rebouças
authors.affiliation: Brazilian Agricultural Research Corporation-EMBRAPA Goats and Sheep, Fazenda Três Lagoas, Sobral/Groaíras Road, Km 4, Sobral, CE 62010-970 Brazil.
authors.forename: Vitor Coutinho Vieira Dos
authors.initials: VC
authors.lastname: Santos
authors.affiliation: College of Dentistry, Federal University of Ceara, Coronel Estanislau Frota Street s/n, Sobral, CE 62010-560, Brazil.
authors.forename: Francisco Cesar Barroso
authors.initials: FC
authors.lastname: Barbosa
authors.affiliation: College of Dentistry, Federal University of Ceara, Coronel Estanislau Frota Street s/n, Sobral, CE 62010-560, Brazil. Electronic address: irianaz@yahoo.com.br.
authors.forename: Iriana Carla Junqueira
authors.initials: IC
authors.lastname: Zanin
mesh_terms: D000890:Anti-Infective Agents / Q000627:therapeutic use*; D003428:Cross Infection / Q000628:therapy*; D004352:Drug Resistance, Microbial; D006801:Humans; D010778:Photochemotherapy; D017319:Photosensitizing Agents / Q000494:pharmacology; D012706:Serratia marcescens
chemical_list: D000890:Anti-Infective Agents; D017319:Photosensitizing Agents
keywords: Antibiotic resistance; Biofilms; Infection disease; Photodynamic antimicrobial chemotherapy; Serratia marcescens