Antimicrobial photodynamic therapy against clinical isolates of carbapenem-susceptible and carbapenem-resistant Acinetobacter baumannii

Author(s)

De Mello, Mirian Marcolan ^[1] ; De Barros, Patricia Pimentel ^[1] ; Bernardes, Renata de Cassia ^[2] ; Alves, Silvio Rubens ^[2] ; Ramanzini, Naiara Pires ^[1] ; Alves Figueiredo-Godoi, Livia Mara ^[1] ; Chipoletti Prado, Ana Carolina ^[1] ; Cardoso Jorge, Antonio Olavo ^[1] ; Junqueira, Juliana Campos ^[1]

Affiliation

^[1] Sao Paulo State Univ UNESP, Inst Sci & Technol, Dept Biosci & Oral Diag, Av Engenheiro Francisco Jose Longo 777, BR-12245000 Sao Jose Dos Campos, SP - Brazil

^[2] Valeclin Clin Anal Lab, Sao Jose Campos, Sao Jose Dos Campos, SP - Brazil

• Document type: Journal article
• Source: Lasers in Medical Science; v. 34, n. 9, p. 1755-1761, DEC 2019.
• Web of Science Citations: 0

Abstract

Infections caused by Acinetobacter baumannii have become a challenge for healthcare professionals because of the rapid increase in Gram-negative bacteria resistant to carbapenem antibiotics. The objective of this study was to evaluate the effect of antimicrobial photodynamic therapy (aPDT) against different strains of A. baumannii isolated from patients with infectious process and hospitalized at the intensive care unit of the hospitals of SAo Jose dos Campos, SAo Paulo. These isolates were obtained from the Valeclin Clinical Analysis Laboratory (SP, Brazil) and were tested for susceptibility to the carbapenems imipenem and meropenem by determination of the minimal inhibitory concentration (MIC) using the broth microdilution method. The strains susceptible and resistant to these antibiotics were submitted to aPDT using methylene blue and a low-level laser with a wavelength of 660 nm and fluence of 39.5 J/cm(2) (energy of 15 J and time of 428 s). The number of colony-forming units (CFU/mL) was analyzed by ANOVA and the Tukey test. The laboratory of origin of the clinical isolates identified 1.54% of 13,715 strains tested over a period of 8 months as A. baumannii. Among the A. baumannii isolates, 58% were resistant to carbapenems by the disk diffusion test. Susceptible isolates exhibited MIC of 0.5 to 1 mu g/mL and resistant isolates of 64 to >128 mu g/mL. PDT reduced the number of A. baumannii cells for all isolates tested, with this reduction ranging from 63 to 88% for susceptible isolates and from 26 to 97% for resistant isolates. The percentage of viability was dependent on the strain analyzed. In conclusion, these data indicate that PDT could be an alternative strategy for the control of infections caused by carbapenem-resistant A. baumannii. (AU)

• FAPESP's process: 14/03937-6 - Association of antibiotics and antimicrobial photodynamic therapy for control of Acinetobacter baumannii
• Grantee: Naiara Pires Ramanzini
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• FAPESP's process: 12/15250-0 - EVALUATION OF TEMPORAL EXPRESSION OF GENES SAP5, SAP9, PLB1, PLB2, LIP9 LIP10 IN INTERACTIONS BETWEEN SPECIES C. albicans, C. tropicalis, C. glabrata and C. krusei.
• Grantee: Patrícia Pimentel de Barros
• Support Opportunities: Scholarships in Brazil - Doctorate