Conjugative plasmids from the IncHI1 incompatibility group play an important role in transferring antibiotic resistance in Salmonella Typhimurium. However, knowledge of their genome structure or gene expression is limited. In this study, we determined the complete nucleotide sequences of four IncHI1 plasmids transferring resistance to antibiotics by two different next generation sequencing protocols and protein expression by mass spectrometry. Sequence data including additional 11 IncHI1 plasmids from GenBank were used for the definition of the IncHI1 plasmid core-genome and pan-genome. The core-genome consisted of approximately 123 kbp and 122 genes while the total pan-genome represented approximately 600 kbp. When the core-genome sequences were used for multiple alignments, the 15 tested IncHI1 plasmids were separated into two main lineages. GC content in core-genome genes was around 46% and 50% in accessory genome genes. A multidrug resistance region present in all 4 sequenced plasmids extended over 20 kbp and, except for tet(B), the genes responsible for antibiotic resistance were those with the highest GC content. IncHI1 plasmids therefore represent replicons that evolved in low GC content bacteria. From their original host, they spread to Salmonella and during this spread these plasmids acquired multiple accessory genes including those coding for antibiotic resistance. Antibiotic-resistance genes belonged to genes with the highest level of expression and were constitutively expressed even in the absence of antibiotics. This is the likely mechanism that facilitates host cell survival when antibiotics suddenly emerge in the environment.

• Klíčová slova
• IncHI1 plasmids, comparative genomic, proteomics,
• MeSH
• antibakteriální látky farmakologie   MeSH
• bakteriální léková rezistence genetika   MeSH
• genom bakteriální genetika   MeSH
• interakce hostitele a patogenu genetika   MeSH
• lidé MeSH
• molekulární evoluce * MeSH
• plazmidy genetika   MeSH
• regulace genové exprese u bakterií účinky léků   MeSH
• Salmonella typhimurium účinky léků   genetika   patogenita   MeSH
• salmonelóza genetika   mikrobiologie   MeSH
• sekvenční analýza DNA MeSH
• vysoce účinné nukleotidové sekvenování MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• antibakteriální látky MeSH

International trade with ornamental fish is gradually recognized as an important source of a wide range of different antibiotic resistant bacteria. In this study we therefore characterized the prevalence of selected antibiotic resistance genes in the microbiota found in the carriage water of ornamental fish originating from 3 different continents. Real-time PCR quantification showed that the sul1 gene was present in 11 out of 100 bacteria. tet(A) was present in 6 out of 100 bacteria and strA, tet(G), sul2 and aadA were present in 1-2 copies per 100 bacteria. Class I integrons were quite common in carriage water microbiota, however, pyrosequencing showed that only 12 different antibiotic gene cassettes were present in class I integrons. The microbiota characterized by pyrosequencing of the V3/V4 variable region of 16S rRNA genes consisted of Proteobacteria (48%), Bacteroidetes (29.5%), Firmicutes (17.8%), Actinobacteria (2.1%) and Fusobacteria (1.6%). Correlation analysis between antibiotic resistance gene prevalence and microbiota composition verified by bacterial culture showed that major reservoirs of sul1 sul2, tet(A), tet(B) tet(G), cat, cml, bla, strA, aacA, aph and aadA could be found among Alpha-, Beta- and Gammaproteobacteria with representatives of Enterobacteriaceae, Pseudomonadaceae, Rhizobiaceae and Comamonadaceae being those most positively associated with the tested antibiotic resistance genes.

• MeSH
• Actinobacteria účinky léků   genetika   MeSH
• antibakteriální látky farmakologie   MeSH
• Bacteria účinky léků   genetika   MeSH
• Bacteroidetes účinky léků   genetika   MeSH
• Fusobacteria účinky léků   genetika   MeSH
• integrony genetika   MeSH
• kvantitativní polymerázová řetězová reakce MeSH
• mikrobiologie vody MeSH
• mikrobiota účinky léků   genetika   MeSH
• mnohočetná bakteriální léková rezistence MeSH
• Proteobacteria účinky léků   genetika   MeSH
• RNA ribozomální 16S genetika   MeSH
• ryby MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• antibakteriální látky MeSH
• RNA ribozomální 16S MeSH