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Unexpected occurrence of plasmid-mediated quinolone resistance determinants in environmental Aeromonas spp.

Cattoir V, Poirel L, Aubert C, Soussy CJ, Nordmann P - Emerging Infect. Dis. (2008)

Bottom Line: The qnrS2 genes were identified from Aeromonas punctata subsp. punctata and A. media.The qnrS2 gene was located on IncU-type plasmids in both isolates, which resulted in increased MIC values of quinolones and fluoroquinolones, once they were transferred into Escherichia coli.This identification of plasmid-mediated qnr genes outside Enterobacteriaceae underlines a possible diffusion of those resistance determinants within gram-negative rods.

View Article: PubMed Central - PubMed

Affiliation: Institut Nationale de la Santé et de la Recherche Médicale Unité 914, Le Kremlin-Bicêtre, France.

ABSTRACT
We searched for plasmid-mediated quinolone resistance determinants of the Qnr type in several water samples collected at diverse locations from the Seine River (Paris, France). The qnrS2 genes were identified from Aeromonas punctata subsp. punctata and A. media. The qnrS2 gene was located on IncU-type plasmids in both isolates, which resulted in increased MIC values of quinolones and fluoroquinolones, once they were transferred into Escherichia coli. The qnrS2 gene identified in A. punctata was part of novel genetic structure corresponding to a mobile insertion cassette element. This identification of plasmid-mediated qnr genes outside Enterobacteriaceae underlines a possible diffusion of those resistance determinants within gram-negative rods.

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Genetic environments of the qnrS2 gene in plasmid p37 from Aeromonas punctata 37 and comparison with related plasmid structures. Plasmid pFBAOT6 is from A. punctata from the United Kingdom (23); plasmids pGNB2 and pMG308 are from a wastewater treatment plant from Germany (unknown bacterial reservoir) (24) and from a non-Typhi Salmonella clinical isolate from the United States (25), respectively. Recombinant plasmid pAS37 has been obtained from our study. Open reading frames (ORFs) are indicated by horizontal arrows. The right and left inverted repeats (IRR and IRL) are indicated, and duplication sites (CCTCC) are represented by black triangles. The EcoRI- restriction sites that have been used for cloning experiments are indicated. The identified mobile insertion cassette element is bracketed by IRL and IRR of 22-bp size (bases in black are identical, and bases in white are different).
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Figure 2: Genetic environments of the qnrS2 gene in plasmid p37 from Aeromonas punctata 37 and comparison with related plasmid structures. Plasmid pFBAOT6 is from A. punctata from the United Kingdom (23); plasmids pGNB2 and pMG308 are from a wastewater treatment plant from Germany (unknown bacterial reservoir) (24) and from a non-Typhi Salmonella clinical isolate from the United States (25), respectively. Recombinant plasmid pAS37 has been obtained from our study. Open reading frames (ORFs) are indicated by horizontal arrows. The right and left inverted repeats (IRR and IRL) are indicated, and duplication sites (CCTCC) are represented by black triangles. The EcoRI- restriction sites that have been used for cloning experiments are indicated. The identified mobile insertion cassette element is bracketed by IRL and IRR of 22-bp size (bases in black are identical, and bases in white are different).

Mentions: Cloning of EcoRI-restricted DNA from whole-cell DNA of A. punctata 37 produced a recombinant plasmid, pAS37, containing a 19,050-bp insert that contained the qnrS2 gene. Sequencing showed that the qnrS2 gene was located in a plasmid-encoded genetic structure previously identified in an IncU-related plasmid, pFBAOT6 (84,748 bp), isolated from an A. punctata strain recovered from hospital sewage in Kendal (United Kingdom) in 1997 (23). This region consisted of 15 open reading frames (Figure 2). Detailed analysis of pAS37 showed that a fragment of 1,375 bp containing the qnrS2 gene (657 bp) was inserted within the mpR gene coding for a putative zinc metalloprotease (MpR) (Figure 2). Sequencing of the full insert in plasmid pAS37 identified the same rep region as reported from the IncU-related pFBAOT6 plasmid, which indicated that p37 was a member of the IncU incompatibility group. PCR amplification that used specific primers of this rep gene also gave positive results from whole-cell DNA of E. coli (p42) transformant, indicating that p42 also belonged to IncU-type plasmid family. In addition, cloning of EcoRI-restricted DNA from whole-cell DNA of A. media 42 showed that the qnrS2 gene was inserted into the mpR gene in plasmid p42. No tetA gene encoding resistance to tetracycline was detected by PCR in plasmids p37 and p42, whereas it was identified in plasmid pFBAOT6 (23).


Unexpected occurrence of plasmid-mediated quinolone resistance determinants in environmental Aeromonas spp.

Cattoir V, Poirel L, Aubert C, Soussy CJ, Nordmann P - Emerging Infect. Dis. (2008)

Genetic environments of the qnrS2 gene in plasmid p37 from Aeromonas punctata 37 and comparison with related plasmid structures. Plasmid pFBAOT6 is from A. punctata from the United Kingdom (23); plasmids pGNB2 and pMG308 are from a wastewater treatment plant from Germany (unknown bacterial reservoir) (24) and from a non-Typhi Salmonella clinical isolate from the United States (25), respectively. Recombinant plasmid pAS37 has been obtained from our study. Open reading frames (ORFs) are indicated by horizontal arrows. The right and left inverted repeats (IRR and IRL) are indicated, and duplication sites (CCTCC) are represented by black triangles. The EcoRI- restriction sites that have been used for cloning experiments are indicated. The identified mobile insertion cassette element is bracketed by IRL and IRR of 22-bp size (bases in black are identical, and bases in white are different).
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Related In: Results  -  Collection

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Figure 2: Genetic environments of the qnrS2 gene in plasmid p37 from Aeromonas punctata 37 and comparison with related plasmid structures. Plasmid pFBAOT6 is from A. punctata from the United Kingdom (23); plasmids pGNB2 and pMG308 are from a wastewater treatment plant from Germany (unknown bacterial reservoir) (24) and from a non-Typhi Salmonella clinical isolate from the United States (25), respectively. Recombinant plasmid pAS37 has been obtained from our study. Open reading frames (ORFs) are indicated by horizontal arrows. The right and left inverted repeats (IRR and IRL) are indicated, and duplication sites (CCTCC) are represented by black triangles. The EcoRI- restriction sites that have been used for cloning experiments are indicated. The identified mobile insertion cassette element is bracketed by IRL and IRR of 22-bp size (bases in black are identical, and bases in white are different).
Mentions: Cloning of EcoRI-restricted DNA from whole-cell DNA of A. punctata 37 produced a recombinant plasmid, pAS37, containing a 19,050-bp insert that contained the qnrS2 gene. Sequencing showed that the qnrS2 gene was located in a plasmid-encoded genetic structure previously identified in an IncU-related plasmid, pFBAOT6 (84,748 bp), isolated from an A. punctata strain recovered from hospital sewage in Kendal (United Kingdom) in 1997 (23). This region consisted of 15 open reading frames (Figure 2). Detailed analysis of pAS37 showed that a fragment of 1,375 bp containing the qnrS2 gene (657 bp) was inserted within the mpR gene coding for a putative zinc metalloprotease (MpR) (Figure 2). Sequencing of the full insert in plasmid pAS37 identified the same rep region as reported from the IncU-related pFBAOT6 plasmid, which indicated that p37 was a member of the IncU incompatibility group. PCR amplification that used specific primers of this rep gene also gave positive results from whole-cell DNA of E. coli (p42) transformant, indicating that p42 also belonged to IncU-type plasmid family. In addition, cloning of EcoRI-restricted DNA from whole-cell DNA of A. media 42 showed that the qnrS2 gene was inserted into the mpR gene in plasmid p42. No tetA gene encoding resistance to tetracycline was detected by PCR in plasmids p37 and p42, whereas it was identified in plasmid pFBAOT6 (23).

Bottom Line: The qnrS2 genes were identified from Aeromonas punctata subsp. punctata and A. media.The qnrS2 gene was located on IncU-type plasmids in both isolates, which resulted in increased MIC values of quinolones and fluoroquinolones, once they were transferred into Escherichia coli.This identification of plasmid-mediated qnr genes outside Enterobacteriaceae underlines a possible diffusion of those resistance determinants within gram-negative rods.

View Article: PubMed Central - PubMed

Affiliation: Institut Nationale de la Santé et de la Recherche Médicale Unité 914, Le Kremlin-Bicêtre, France.

ABSTRACT
We searched for plasmid-mediated quinolone resistance determinants of the Qnr type in several water samples collected at diverse locations from the Seine River (Paris, France). The qnrS2 genes were identified from Aeromonas punctata subsp. punctata and A. media. The qnrS2 gene was located on IncU-type plasmids in both isolates, which resulted in increased MIC values of quinolones and fluoroquinolones, once they were transferred into Escherichia coli. The qnrS2 gene identified in A. punctata was part of novel genetic structure corresponding to a mobile insertion cassette element. This identification of plasmid-mediated qnr genes outside Enterobacteriaceae underlines a possible diffusion of those resistance determinants within gram-negative rods.

Show MeSH
Related in: MedlinePlus