Microbiologia
URI permanente desta comunidadehttps://locus.ufv.br/handle/123456789/11840
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Item Evidence of illegitimate recombination between two pasteurellaceae plasmids resulting in a novel multi-resistance replicon, pM3362MDR, in Actinobacillus pleuropneumoniae(Frontiers in Microbiology, 2018-10) Silva, Giarlã Cunha da; Li, Yinghui; Li, Yanwen; Rossi, Ciro C.; Crespo, Roberto Fernandez; Williamson, Susanna M.; Langford, Paul R.; Bazzolli, Denise Mara Soares; Bossé, Janine T.Evidence of plasmids carrying the tetracycline resistance gene, tet(B), was found in the previously reported whole genome sequences of 14 United Kingdom, and 4 Brazilian, isolates of Actinobacillus pleuropneumoniae. Isolation and sequencing of selected plasmids, combined with comparative sequence analysis, indicated that the four Brazilian isolates all harbor plasmids that are nearly identical to pB1001, a plasmid previously found in Pasteurella multocida isolates from Spain. Of the United Kingdom isolates, 13/14 harbor plasmids that are (almost) identical to pTetHS016 from Haemophilus parasuis. The remaining United Kingdom isolate, MIDG3362, harbors a 12666 bp plasmid that shares extensive regions of similarity with pOV from P. multocida (which carries bla ROB−1 , sul2, and strAB genes), as well as with pTetHS016. The newly identified multi-resistance plasmid, pM3362MDR, appears to have arisen through illegitimate recombination of pTetHS016 into the stop codon of the truncated strB gene in a pOV-like plasmid. All of the tet(B)-carrying plasmids studied were capable of replicating in Escherichia coli, and predicted origins of replication were identified. A putative origin of transfer (oriT) sequence with similar secondary structure and a nic-site almost identical to that of RP4 was also identified in these plasmids, however, attempts to mobilize them from an RP4-encoding E. coli donor strain were not successful, indicating that specific conjugation machinery may be required.Item Antimicrobial resistance, biofilm formation and virulence reveal Actinobacillus pleuropneumoniae strains' pathogenicity complexity(Research in Veterinary Science, 2018-06) Pereira, Monalessa Fábia; Rossi, Ciro César; Seide, Larissa Eler; Martins Filho, Sebastião; Dolinski, Cláudia de Melo; Bazzolli, Denise Mara SoaresPorcine pleuropneumonia is an important cause of lowered productivity and economic loss in the pig industry worldwide, associated primarily with Actinobacillus pleuropneumoniae infection. Its colonization and persistence within the upper respiratory tract of affected pigs depends upon interactions between a number of genetically controlled virulence factors, such as pore-forming repeats-in-toxin exoproteins, biofilm formation, and antimicrobial resistance. This study investigated correlations between biofilm-forming capacity, antimicrobial resistance, and virulence of A. pleuropneumoniae obtained from clinical outbreaks of disease, using a Galleria mellonella alternative infection model. Results suggest that virulence is diverse amongst the 21 strains of A. pleuropneumoniae examined and biofilm formation correlated with genetic control of antimicrobial resistance.Item p518, a small floR plasmid from a south american isolate of Actinobacillus pleuropneumoniae(Veterinary Microbiology, 2017-04-21) Silva, Giarlã Cunha da; Rossi, Ciro César; Santana, Mateus Ferreira; Langford, Paul R.; Bossé, Janine T.; Bazzolli, Denise Mara SoaresA small (3.9 kb) plasmid (p518), conferring resistance to florfenicol (MIC >8 μg/mL) and chloramphenicol (MIC >8 μg/mL) was isolated from an Actinobacillus pleuropneumoniae clinical isolate from Southeastern Brazil. To date, this is the smallest florfenicol resistance plasmid isolated from a member of the Pasteurellaceae. The complete nucleotide of this plasmid revealed a unique gene arrangement compared to previously reported florfenicol resistance plasmids found in other members of the Pasteurellaceae. In addition to the floR gene and a lysR gene, common to various florfenicol resistance plasmids, p518 also encodes strA and a partial strB sequence. An origin of replication (oriV) similar to that in the broad host range plasmid, pLS88, was identified in p518, and transformation into Escherichia coli MFDpir confirmed the ability to replicate in other species. Mobilisation genes appear to have been lost, with only a partial mobC sequence remaining, and attempts to transfer p518 from a conjugal donor strain (E. coli MFDpir) were not successful, suggesting this plasmid is not mobilisable. Similarly, attempts to transfer p518 into a competent A. pleuropneumoniae strain, MIDG2331, by natural transformation were also not successful. These results suggest that p518 may be only transferred by vertical descent.