Comparative sequence analysis of a multidrug-resistant plasmid from Aeromonas hydrophila.
Aeromonas hydrophila is a pathogenic bacterium that has been implicated in fish, animal, and human disease. Recently, a multidrug resistance (MDR) plasmid, pR148, was isolated from A. hydrophila obtained from a tilapia (Oreochromis niloticus) farm in Thailand. pR148 is a 165,906-bp circular plasmid containing 147 coding regions showing highest similarity to pNDM-1_Dok1, an MDR plasmid isolated from a human pathogen. pR148 was also very similar to other IncA/C plasmids isolated from humans, animals, food, and fish. pR148 contains a mercuric resistance operon and encodes the complete set of genes for the type 4 secretion system. pR148 encodes a Tn21 type transposon. This transposon contains the drug resistance genes qacH, bla(OXA-10), aadA1, and sul1 in a class 1 integron; tetA and tetR in transposon Tn1721; and catA2 and a duplicate sul1 in a locus showing 100% similarity to IncU plasmids isolated from fish. The bla(OXA-10) and aadA1 genes showed 100% similarity to those from the Acinetobacter baumannii AYE genome. The similarity of pR148 to a human pathogen-derived plasmid indicates that the plasmids were either transferred between different genera or that they are derived from a common origin. Previous studies have shown that IncA/C plasmids retain a conserved backbone, while the accessory region points to lateral gene transfer. These observations point out the dangers of indiscriminate use of antibiotics in humans and in animals and the necessity of understanding how drug resistance determinants are disseminated and transferred.
Aquatic Biotechnology Center of WCU Project, College of Veterinary Medicine, Gyeongsang National University, Jinju, Gyeongnam, South Korea.
Carmelo S
CS
Del Castillo
Jun-Ichi
J
Hikima
Ho-Bin
HB
Jang
Seong-Won
SW
Nho
Tae-Sung
TS
Jung
Janenuj
J
Wongtavatchai
Hidehiro
H
Kondo
Ikuo
I
Hirono
Haruko
H
Takeyama
Takashi
T
Aoki
D040981:Acinetobacter baumannii / Q000235:genetics; D016980:Aeromonas hydrophila / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D004251:DNA Transposable Elements; D024901:Drug Resistance, Multiple, Bacterial / Q000187:drug effects / Q000235:genetics*; D005398:Fisheries; D053263:Gene Regulatory Networks; D022761:Gene Transfer, Horizontal; D005798:Genes, Bacterial; D006801:Humans; D032023:Integrons; D010802:Phylogeny; D058974:Phylogeography; D010957:Plasmids / Q000737:chemistry* / Q000302:isolation & purification; D017422:Sequence Analysis, DNA; D017210:Tilapia / Q000382:microbiology; D001618:beta-Lactamases / Q000235:genetics*
D000900:Anti-Bacterial Agents; D004251:DNA Transposable Elements; D001618:beta-Lactamases