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Genomic insights into arsenic and antibiotic resistance in Comamonas thiooxydans strains F1-6 and A7-5
Author(s)
Sitlaothaworn, Kanchana
Phongsopitanun, Wongsakorn
Chitpirom, Kitja
Lee, Jung Sook
Tanasupawat, Somboon
Date Issued
April 1, 2026
Type
Article
Abstract
Two arsenic-resistant, Gram-negative, aerobic rod-shaped bacterial strains, F1-6 and A7-5, which were isolated from agricultural soil in Thailand, were systematically studied. They grew at 30 °C, pH 5–11, and in 3% (w/v) NaCl. Ubiquinone with eight isoprene units (Q-8) and the cellular fatty acids C16:0, C18:1 ω7c, and C17:0 CYCLO were the major components. Phylogenetic analysis via 16S rRNA gene sequences revealed that strains F1-6 and A7-5 were affiliated with the genus Comamonas and closely related to C. thiooxydans DF2T and C. testosteroni KCTC 2990T, with 99.79% and 99.86% similarity, respectively. The average nucleotide identity and digital DNA-DNA hybridization values between F1-6 and C. thiooxydans DF2T were 97.89% and 85.7%, respectively, whereas those between A7-5 and C. thiooxydans DF2T were 97.23% and 81.3%, respectively. Thus, both the F1-6 and A7-5 were identified as C. thiooxydans. The draft genome sizes of F1-6 and A7-5 were 5.2 and 5.3 Mb, comprising 87 and 84 contigs, with DNA G+C contents of 61.5% and 61.4%, respectively. The genomes of both strains contained ars cluster genes and many genes for growth and resistance to heavy metals and antibiotics, similar to those of C. testosteroni ATCC 11996T, C. thiooxydans CNB-1 substr. CNB-2 Chr, and C. terrae NBRC 106524T. Nevertheless, the acr3, qacG, and vanH genes in the vanO cluster were found only in C. terrae NBRC 106524T. This study provides more comprehensive insight into As-resistant bacteria and could be applied to the bioremediation of As and other heavy metals in the future.
Citation
Scienceasia, 52(2), 2026