Antibacterial effect of acetic acid during an outbreak of carbapenem-resistant Acinetobacter baumannii in an ICU (II)

Abstract

Introduction: Acetic acid (AA) has been commonly used in medicine as an antiseptic agent for the past 6000 years. This study evaluated the antibacterial effect of AA during an outbreak in an intensive care unit (ICU) facility in Baja California Sur, México.

Methodology: Thirty-five environmental samples were collected, subsequently, disinfection with AA (4%) was performed, and two days later the same areas were sampled inside the ICU facility. Carbapenem-resistant A. baumannii (CRAB) was detected with loop-mediated isothermal amplification assay (Garciglia-Mercado et al. companion paper), targeting blaOXA-23-like, blaOXA-24-like, blaOXA-51-like, blaOXA-58-like, blaIMP and blaVIM genes. CRAB isolates before and after disinfection were compared by PFGE.

Results: Eighteen (54.5%) and five (14.3%) of thirty-five environmental samples were identified as Acinetobacter baumannii before and after disinfection, respectively, showing a significant decrease of 85.7% (p < 0.05) both by Loop-mediated isothermal amplification (LAMP) and polymerase chain reaction (PCR). Furthermore, the presence of blaOXA-23-like and blaOXA-58-like genes significantly decreased (p < 0.05) both by LAMP and PCR methods. PFGE genotype showed high similarity among CRAB isolates before and after disinfection, suggesting wide clonal dissemination in the ICU facility.

Conclusions: This study demonstrated the novel application of AA with the LAMP assays developed for detecting CRAB. AA promises to be a cheap and efficacious disinfectant alternative to both developed and especially developing countries, preventing the spread of this organism in the environment and to other susceptible patients in health care settings.

Keywords: Acinetobacter baumannii; Carbapenem-resistance; acetic acid; loop-mediated isothermal amplification.