Ticiana Mont Alverne Lopes Parente1, Emanuela de Lima Rebouças1, Vitor Coutinho Vieira Dos Santos2, Francisco Cesar Barroso Barbosa3, Iriana Carla Junqueira Zanin4. 1. Biotechnology Post-Graduate Program, Federal University of Ceara, Comandante Mauricélio, Rocha Pontes Street, 100, Sobral, CE 62.042-280 Brazil. 2. Brazilian Agricultural Research Corporation-EMBRAPA Goats and Sheep, Fazenda Três Lagoas, Sobral/Groaíras Road, Km 4, Sobral, CE 62010-970 Brazil. 3. College of Dentistry, Federal University of Ceara, Coronel Estanislau Frota Street s/n, Sobral, CE 62010-560, Brazil. 4. College of Dentistry, Federal University of Ceara, Coronel Estanislau Frota Street s/n, Sobral, CE 62010-560, Brazil. Electronic address: irianaz@yahoo.com.br.
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.
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: Mathijs J P Theelen; W David Wilson; Barbara A Byrne; Judy M Edman; Philip H Kass; Lapo Mughini-Gras; K Gary Magdesian Journal: J Vet Intern Med Date: 2020-02-05 Impact factor: 3.333