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Serratia marcescens resistance profile and its susceptibility to photodynamic antimicrobial chemotherapy

Ticiana Mont Alverne Lopes Parente1, Emanuela de Lima Rebouças1, Vitor Coutinho Vieira Dos Santos2

  • 1Biotechnology Post-Graduate Program, Federal University of Ceara, Comandante Mauricélio, Rocha Pontes Street, 100, Sobral, CE 62.042-280 Brazil.

Photodiagnosis and Photodynamic Therapy
|April 18, 2016
PubMed
Abstract

Insights

Photodynamic antimicrobial chemotherapy (PACT) effectively targets both planktonic Serratia marcescens and biofilms. This study highlights increasing resistance to common antibiotics, underscoring PACT

Area of Science:

  • Antimicrobial chemotherapy
  • Microbiology
  • Infectious diseases

Background:

  • Limited studies evaluate photodynamic antimicrobial chemotherapy (PACT) efficacy against Serratia marcescens.
  • PACT's effectiveness on planktonic cultures and biofilms of S. marcescens requires further investigation.
  • Nosocomial infections caused by S. marcescens necessitate novel treatment strategies.

Purpose of the Study:

  • To assess the antibiotic resistance profile of Serratia marcescens.
  • To determine the susceptibility of S. marcescens planktonic cultures and biofilms to PACT.
  • To compare antibiotic resistance patterns using CLSI 2007 and CLSI 2015 guidelines.

Main Methods:

  • Antimicrobial susceptibility testing of 55 S. marcescens strains using E-test® against cefotaxime, imipenem, ciprofloxacin, tobramycin, and doxycycline.
  • Application of PACT using a light-emitting diode and toluidine blue (TBO) on planktonic cultures and biofilms.
  • Analysis of resistance data comparing Clinical and Laboratory Standards Institute (CLSI) 2007 and 2015 guidelines.

Main Results:

  • S. marcescens exhibited intermediate sensitivity to cefotaxime, imipenem, tobramycin, and doxycycline, with resistance to cefotaxime, tobramycin, doxycycline, and ciprofloxacin.
  • A notable increase in S. marcescens resistance was observed between CLSI 2007 and CLSI 2015 standards.
  • PACT demonstrated significant bacterial reduction in both planktonic cultures (10^11 to 10^7) and biofilms (10^10 to 10^7) without statistical difference.
  • Imipenem showed the lowest resistance rate among the tested antibiotics.

Conclusions:

  • Serratia marcescens demonstrates evolving resistance to common antibiotics, with imipenem remaining a more effective agent.
  • Photodynamic antimicrobial chemotherapy (PACT) is a viable treatment option for both planktonic S. marcescens and early-stage biofilms.
  • The findings support PACT as a promising therapeutic strategy against S. marcescens infections, including those in biofilm states.
Keywords:
Antibiotic resistanceBiofilmsInfection diseasePhotodynamic antimicrobial chemotherapySerratia marcescens

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