Background: Acinetobacter baumannii is the leading multidrug resistant agent in Vietnamese health care systems in the second decade of the 21st century. Nowadays, an effective treatment for Acinetobacter baumannii carrying the genes encoding the enzymes hydrolyzed carbapenemase the most important problem for the clinicians. Objective: Determination of antibiotic resistance characteristics, ratio of genes related to carbapenem resistance and in-vitro bactericidal effect of antibiotic combinations on A. baumannii. Method: Retrospective descriptive analysis study. Carbapenem-resistant A. baumannii were collected from patients with HAP in Thongnhat General Hospital of Dongnai Province from January 2013 to December 2017. Results: Number of A. baumannii strains studied was 105. A. baumannii was 100% sensitive to colistin and 99.1% with tigecycline. 100% A. baumannii has MIC of meropenem ≥ 32µg/ml. There are 87% MIC colistin with 1µg/ml and 0.9% MIC tigecycline> 2 µg/ml. Meropenem/colistin and meropenem/rifampicin combinations have synergistic and additive effects with very high rates, 94.3% and 81.9%, respectively, to A. baumannii. However, tigecycline/colistin combination only gives synergistic additive effects at a rate of 36.2%. The effect of colistin at concentration of 1 µg/ml or rifampicin at a concentration of 2 µg/ml under MIC can convert A. baumannii from non-sensitive to meropenem to susceptible ones at high rates. Class D carbapenemase coding genes include blaOXA-51, blaOXA-23, blaOXA-58 distributed in A. baumannii with 97.1%; 79% and 7.6%, respectively. Whereas, blaNDM-1 carbapenemase gene of class B was distributed in A. baumannii with the rate of 13.3% and no blaKPC gene of class A carbapenemase encoded in A. baumannii was recorded. In this study, 93.3% of carbapenem resistant A. baumannii strains carried ISAba1. Conclusion: A. baumannii is resistant to carbapenem due to carrying multiple carbapenemase genes and in-vitro tigecycline/colistin combination for a lower bactericidal effect for A. baumannii than meropenem/colistin and meropenem/rifampicin.
Dr. Nguyen Si-Tuan graduated with a master’s degree in Molecular microbiology at Paris sud11 University in 2010 and graduated with a PhD’s degree in Biotechnology at Ho Chi Minh National University in 2014. He has published 8 ISI papers with 18 citations and 3 h-index. I am the Head of the Department of Clinical Microbiology of Thongnhat General Hospital of Dongnai Province, Vietnam from 2014 to the present.
Activities (From 2013 – 2019):
➢ Speaker at 12th ASIAN Network for Clinical Laboratory Standardization and Harmonization (ANCLS) International Congress in 2013.
➢ Poster presentation at 11th International Symposium on the Biology of Acinetobacter in 2017.
➢ Speaker at the 8th ASEAN Conference on Tropical Medicine and Parasitology (ACTMP) 2018.
➢ Poster presentation at the ASM (American Society for Microbiology) Conference on Rapid Applied Microbial Next-Generation Sequencing and Bioinformatics Pipelines, September 23 – 26, 2018 in Tysons, VA, USA.
➢ Speaker at the 1st International Congress on Microbiology and One – Health in 2018.
➢ Speaker at the 4th Pan – ASIAN Biomedical Science Conference help in 2018.
➢ Speaker at the 7th European Clinical Microbiology Congress, November 01 – 02, 2018 at London, United Kingdom.
➢ Speaker at the 9th International Congress of the Asia Pacific Society of Infectious Control in 2019