Characterization of Small ColE-Like Plasmids Mediating Widespread Dissemination of the
            <i>qnrB19</i>
            Gene in Commensal Enterobacteria

cWe studied a collection of 105 clinical enterobacteria with unusual phenotypes of quinolone susceptibility to analyze the occurrence of plasmid-mediated quinolone resistance (PMQR) and oqx genes and their implications for quinolone susceptibility. The oqxA and oqxB genes were found in 31/34 (91%) Klebsiella pneumoniae and 1/3 Klebsiella oxytoca isolates. However, the oqxAand oqxB-harboring isolates lacking other known quinolone resistance determinants showed wide ranges of susceptibility to nalidixic acid and ciprofloxacin. Sixty of the 105 isolates (57%) harbored at least one PMQR gene [qnrB19, qnrB10, qnrB2, qnrB1, qnrS1, or aac(6=)-Ib-cr)], belong to 8 enterobacterial species, and were disseminated throughout the country, and most of them were categorized as susceptible by the current clinical quinolone susceptibility breakpoints. We developed a disk diffusionbased method to improve the phenotypic detection of aac(6=)-Ib-cr. The most common PMQR genes in our collection [qnrB19, qnrB10, and aac(6=)-Ib-cr] were differentially distributed among enterobacterial species, and two different epidemiological settings were evident. First, the species associated with community-acquired infections (Salmonella spp. and Escherichia coli) mainly harbored qnrB19 (a unique PMQR gene) located in small ColE1-type plasmids that might constitute its natural reservoirs. qnrB19 was not associated with an extended-spectrum ␤-lactamase phenotype. Second, the species associated with hospital-acquired infections (Enterobacter spp., Klebsiella spp., and Serratia marcescens) mainly harbored qnrB10 in ISCR1-containing class 1 integrons that may also have aac(6=)-Ib-cr as a cassette within the variable region. These two PMQR genes were strongly associated with an extended-spectrum ␤-lactamase phenotype. Therefore, this differential distribution of PMQR genes is strongly influenced by their linkage or lack of linkage to integrons.

Section: Fig 2 Phenotypic Approaches To Detect Aac(6=)-ib-crsupporting

confidence: 74%

Differential Distribution of Plasmid-Mediated Quinolone Resistance Genes in Clinical Enterobacteria with Unusual Phenotypes of Quinolone Susceptibility from Argentina

Andres

Lucero

Soler-Bistué

et al. 2013

“…Plasmid pPAB19-1 is identical to a plasmid that has been isolated from E. coli, E. fergusonii, E. hermanii, Enterobacter aerogenes, K. pneumoniae, S. enterica, and Kluyvera ascorbata strains from the Netherlands, Bolivia, Peru, and Colombia by different research groups and has received several names (pSGI15, pECY6-7, and pMK100) (12,17,21,22). Plasmids pPAB19-2, pPAB19-3, and pPAB19-4 are highly related to pPAB19-1 and other plasmids such as pECC14-9 (Bolivia and Peru) and pMK101 (Colombia) isolated from E. coli and S. enterica, respectively (17,21,22). A ColE1-type replication region locus is within the fragment that is common to all plasmids and share 93% identity with other non-qnrB-carrying plasmids from enterobacteria such as pJHCMW1 (29).…”

Section: Resultsmentioning

confidence: 99%

“…An interesting characteristic of the qnrB19 allele is that it has been found within large plasmids, associated to ISEcp1C-based transposons (6,9,27), and in small plasmids (ϳ3 kbp) lacking ISEcp1C or any other insertion sequence (12,17,22) (Table 1). However, in spite of being located in such dissimilar elements, the qnrB19 genes share a conserved genetic environment (22).…”

mentioning

confidence: 99%

“…The first qnrB gene (qnrB1) was identified in a plasmid from a K. pneumoniae strain isolated in South India (16), and 38 members of the family quickly followed (http://www.lahey .org/qnrStudies/) (13). The qnrB19 gene has been found in several genera of Enterobacteriaceae isolated from humans (healthy people and clinical isolates), animals, and food of animal origin in numerous geographical regions (6,9,12,17,21,22,27). An interesting characteristic of the qnrB19 allele is that it has been found within large plasmids, associated to ISEcp1C-based transposons (6,9,27), and in small plasmids (ϳ3 kbp) lacking ISEcp1C or any other insertion sequence (12,17,22) (Table 1).…”

mentioning

confidence: 99%

See 1 more Smart Citation

Small Plasmids Harboring qnrB19 : a Model for Plasmid Evolution Mediated by Site-Specific Recombination at oriT and Xer Sites

Tran

Andres

Petroni

et al. 2012

Plasmids pPAB19-1, pPAB19-2, pPAB19-3, and pPAB19-4, isolated from Salmonella and Escherichia coli clinical strains from hospitals in Argentina, were completely sequenced. These plasmids include the qnrB19 gene and are 2,699, 3,082, 2,989, and 2,702 nucleotides long, respectively, and they share extensive homology among themselves and with other previously described small qnrB19-harboring plasmids. The genetic environment of qnrB19 in all four plasmids is identical to that in these other plasmids and in transposons such as Tn2012, Tn5387, and Tn5387-like. Nucleotide sequence comparisons among these and previously described plasmids showed a variable region characterized by being flanked by an oriT locus and a Xer recombination site. We propose that this arrangement could play a role in the evolution of plasmids and present a model for DNA swapping between plasmid molecules mediated by site-specific recombination events at oriT and a Xer target site. Qnrs are pentapeptide repeat proteins that mediate resistance to quinolones by protecting type II DNA topoisomerases (14, 28). They are known since 1998 when the first qnr gene was found in the multiresistance plasmid pMG252 harbored by a Klebsiella pneumoniae strain isolated from the urine of a patient at the University of Alabama (20). Since then five qnr families (qnrA, qnrB, qnrC, qnrD, and qnrS) have been found, usually hosted in large plasmids (31). The first qnrB gene (qnrB1) was identified in a plasmid from a K. pneumoniae strain isolated in South India (16), and 38 members of the family quickly followed (http://www.lahey .org/qnrStudies/) (13). The qnrB19 gene has been found in several genera of Enterobacteriaceae isolated from humans (healthy people and clinical isolates), animals, and food of animal origin in numerous geographical regions (6,9,12,17,21,22,27). An interesting characteristic of the qnrB19 allele is that it has been found within large plasmids, associated to ISEcp1C-based transposons (6,9,27), and in small plasmids (ϳ3 kbp) lacking ISEcp1C or any other insertion sequence (12,17,22) (Table 1). However, in spite of being located in such dissimilar elements, the qnrB19 genes share a conserved genetic environment (22).We have recently analyzed a collection of clinical enterobacterial isolates with decreased quinolone susceptibility, and we found four small plasmids harboring qnrB19 (2). We describe here their molecular features and characterize their relationships with other qnrB19-harboring genetic platforms. Furthermore, we propose possible pathways of evolution of the qnrB19 environment as well as a site-specific recombination-based model for DNA modifications at a variable region found in these plasmids. MATERIALS AND METHODSBacterial strains and plasmids. The plasmids pPAB19-1, pPAB19-2, pPAB19-3, and pPAB19-4 analyzed in the present study were isolated from Salmonella enterica serovar Infantis M7849, Escherichia coli M9996, E. coli M9888, and Salmonella sp. strain M9397, respectively (Table 1). Salmonella Infantis M7849 was isolated at the ...

“…PCR-based inc/rep typing (PBRT) and plasmid sizing determined that the qnrB19 plasmid was a 7-kb ColE PB plasmid, while the qnrB6 plus aac(6Ј)-1b-cr plasmid was a 60-kb IncN and ColE-type plasmid (2,7,13). Of the four remaining plasmids, two were 60 kb and two were 80 kb in size, and all were untypeable for the replicons currently included in the PBRT scheme.…”

mentioning

confidence: 99%

Decreased Susceptibility to Ciprofloxacin among Shigella Isolates in the United States, 2006 to 2009

Folster

Pecic

Bowen

et al. 2011

We characterized 20Shigellaisolates with decreased susceptibility to fluoroquinolones. Most patients (80%) from whom a travel history was obtained reported travel to South or Southeast Asia. Mutations within the quinolone resistance determining regions ofgyrAandparCand plasmid-mediated resistance determinants (qnrB,qnrS, andaac(6′)-Ib-cr) were identified. The rise in antimicrobial resistance amongShigellaisolates may necessitate the increased use of extended-spectrum cephalosporins or macrolides in some patients.