ABSTRACTTwo A/C incompatibility group (IncA/C family) plasmids from the 1960s have been sequenced and classified into the A/C2type 1 group. R16a and IP40a contain novel antibiotic resistance islands and a complete GIsul2 genomic island not previously found in the family. In the 173.1-kb R16a, the 29.9-kb antibiotic resistance island (ARI) is located in a unique backbone position not utilized by ARIs. ARIR16aconsists of Tn1, Tn6020, and Tn6333, harboring the resistance genesblaTEM-1DandaphA1band amermodule, respectively; a truncated Tn5393copy; and a gene cluster with unknown function. Plasmid IP40a is 170.4 kb in size and contains a 5.6-kb ARI inserted into thekfrAgene. ARIIP40acarryingblaTEM-1DandaphA1bgenes is composed of Tn1with a Tn6023insertion. Additionally, IP40a harbors single IS2, IS186, and Tn1000insertions scattered in the backbone; an IS150copy in GIsul2; and a complete Tn6333carrying amermodule at the position of ARIR16a. Loss of resistance markers in R16a, IP40a, and R55 was observed during stability tests. Every phenotypic change proved to be the result of recombination events involving mobile elements. Intramolecular transposition of IS copies that generated IP40a derivatives lacking large parts of the backbone could account for the formation of other family members, too. The MinION platform proved to be a valuable tool in bacterial genome sequencing since it generates long reads that span repetitive elements and facilitates full-length plasmid or chromosome assembly. Nanopore technology enables rapid characterization of large, low-copy-number plasmids and their rearrangement products.
Rapid evolution and host immunity drive the rise and fall of carbapenem resistance during an acute Pseudomonas aeruginosa infection
