Recombination among plasmid-borne genetic platforms containing blaOXA-58 genes in the pan-dissemination of carbapenem resistance in Acinetobacter spp

CAMERANESI MARÍA M.; MORÁN BARRIO JORGELINA; LIMANSKY ADRIANA S.; VIALE ALEJANDRO M

Córdoba

Congreso; XI Congreso Argentino de Microbiología General; 2015

SAMIGE

Over-production of carbapenem-hydrolyzing class D b-lactamases (CHDLs) is the most frequentcause of carbapenem resistance among multi-drug resistant (MDR) ACB complex members such asthe Acinetobacter baumannii, A. pittii and A. nosocomialis which account for the majority ofb-lactamases (CHDLs) is the most frequentcause of carbapenem resistance among multi-drug resistant (MDR) ACB complex members such asthe Acinetobacter baumannii, A. pittii and A. nosocomialis which account for the majority ofAcinetobacter baumannii, A. pittii and A. nosocomialis which account for the majority ofAcinetobacter infections (1). Short genomic sequences designated Re27 sequences are implicated insite specific recombination processes involved in the evolution of many plasmids (2). Thesesequences have been associated with particular replicase genes and could constitute favoredinsertion sites for structures carrying CHDL genes (3).We characterized here a non-conjugative plasmid (pAb242) from a carbapenem- andaminoglycoside-resistant MDR A. baumannii strain carrying a genetic platform containing blaOXA-58infections (1). Short genomic sequences designated Re27 sequences are implicated insite specific recombination processes involved in the evolution of many plasmids (2). Thesesequences have been associated with particular replicase genes and could constitute favoredinsertion sites for structures carrying CHDL genes (3).We characterized here a non-conjugative plasmid (pAb242) from a carbapenem- andaminoglycoside-resistant MDR A. baumannii strain carrying a genetic platform containing blaOXA-58A. baumannii strain carrying a genetic platform containing blaOXA-58andaphA6 genes, and searched for the presence of Re27-like sites in this structure. We alsoconducted a comparative analysis with similar platforms present in previously reported plasmids fromother Acinetobacter spp.The pAb242 platform encompasses ~9 kbp and is bracketed by two Re27-like recombination sites,and is contiguous to a resolvase gene of the serine-recombinase family thus containing all necessaryresources for intra-genomic mobilization. blaOXA-58 is embedded in this platform into an imperfectcomposite Tn3-like transposon in which the upstream 5´-ISAba3 was targeted by an ISAba825aphA6 genes, and searched for the presence of Re27-like sites in this structure. We alsoconducted a comparative analysis with similar platforms present in previously reported plasmids fromother Acinetobacter spp.The pAb242 platform encompasses ~9 kbp and is bracketed by two Re27-like recombination sites,and is contiguous to a resolvase gene of the serine-recombinase family thus containing all necessaryresources for intra-genomic mobilization. blaOXA-58 is embedded in this platform into an imperfectcomposite Tn3-like transposon in which the upstream 5´-ISAba3 was targeted by an ISAba825Acinetobacter spp.The pAb242 platform encompasses ~9 kbp and is bracketed by two Re27-like recombination sites,and is contiguous to a resolvase gene of the serine-recombinase family thus containing all necessaryresources for intra-genomic mobilization. blaOXA-58 is embedded in this platform into an imperfectcomposite Tn3-like transposon in which the upstream 5´-ISAba3 was targeted by an ISAba825blaOXA-58 is embedded in this platform into an imperfectcomposite Tn3-like transposon in which the upstream 5´-ISAba3 was targeted by an ISAba8253-like transposon in which the upstream 5´-ISAba3 was targeted by an ISAba825element. araC1 and lysE regulatory genes were found downstream of the second ISAba3 of the Tn3araC1 and lysE regulatory genes were found downstream of the second ISAba3 of the Tn3element, being lysE disrupted by TnaphA6. MAUVE comparisons with other nine platforms fromlysE disrupted by TnaphA6. MAUVE comparisons with other nine platforms fromAcinetobacter plasmids showed in all cases a similar arrangement containing blaOXA-58, araC1 andplasmids showed in all cases a similar arrangement containing blaOXA-58, araC1 andlysE genes. On the contrary, distinctive features were found between similar platforms such asdifferent ISs disrupting the 5´-ISAba3 element at different positions, and different insertions sites forTnaphA6 into lysE. Re27-like recombination sites were identified bordering the correspondingplatforms in seven of the above arrangements. These Re27-like sequences allow the occurrence ofmultiple recombination processes, thus promoting different arrangements of blaOXA-58 containingregions such as inversion mechanisms and plasmid concatenate formation. These platforms wereidentified in different context, i.e. 30-100 kbp plasmids, some of them containing more than one repgenes. On the contrary, distinctive features were found between similar platforms such asdifferent ISs disrupting the 5´-ISAba3 element at different positions, and different insertions sites forTnaphA6 into lysE. Re27-like recombination sites were identified bordering the correspondingplatforms in seven of the above arrangements. These Re27-like sequences allow the occurrence ofmultiple recombination processes, thus promoting different arrangements of blaOXA-58 containingregions such as inversion mechanisms and plasmid concatenate formation. These platforms wereidentified in different context, i.e. 30-100 kbp plasmids, some of them containing more than one repAba3 element at different positions, and different insertions sites forTnaphA6 into lysE. Re27-like recombination sites were identified bordering the correspondingplatforms in seven of the above arrangements. These Re27-like sequences allow the occurrence ofmultiple recombination processes, thus promoting different arrangements of blaOXA-58 containingregions such as inversion mechanisms and plasmid concatenate formation. These platforms wereidentified in different context, i.e. 30-100 kbp plasmids, some of them containing more than one repaphA6 into lysE. Re27-like recombination sites were identified bordering the correspondingplatforms in seven of the above arrangements. These Re27-like sequences allow the occurrence ofmultiple recombination processes, thus promoting different arrangements of blaOXA-58 containingregions such as inversion mechanisms and plasmid concatenate formation. These platforms wereidentified in different context, i.e. 30-100 kbp plasmids, some of them containing more than one repblaOXA-58 containingregions such as inversion mechanisms and plasmid concatenate formation. These platforms wereidentified in different context, i.e. 30-100 kbp plasmids, some of them containing more than one repi.e. 30-100 kbp plasmids, some of them containing more than one repgene.