<i>bla</i>
            <sub>CTX-M-2</sub>
            Is Located in an Unusual Class 1 Integron (In35) Which Includes Orf513

Arduino, S.; Roy, Paul H.; Jacoby, George A.; Orman, Betina; Piñeiro, Silvia A.; Centrón, Daniela

doi:10.1128/aac.46.7.2303-2306.2002

Cited by 96 publications

(81 citation statements)

References 19 publications

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“…The combination of bla CTX-M-2 linked to ISCR1 is common in clinical isolates from South America (3,4,35,50), and this resistance gene encodes 69% of the extended-spectrum ␤-lactamases found in clinical isolates from Argentinean hospitals (3). Since a bla CTX-M-2 gene linked to ISCR1 was present in strain 12863, we designed primer pairs HS819/HS820, specific for ISCR1, and HS856/HS857, specific for bla CTX-M-2 (Table 1), and screened all 21 class 1-positive strains for their presence.…”

Section: Resultsmentioning

confidence: 99%

Urinary Tract Infections in a South American Population: Dynamic Spread of Class 1 Integrons and Multidrug Resistance by Homologous and Site-Specific Recombination

et al. 2008

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One hundred four bacterial strains mediating urinary tract infections in separate individuals from a Uruguayan community were isolated. Forty-six strains conferred a multidrug resistance phenotype. All 104 strains were examined for the presence of class 1, 2, and 3 integrons. Class 1 integrons were found in 21 isolates across four distinct bacterial genera. A large class 1 integron in a Klebsiella pneumoniae strain was fully sequenced and was 29,093 bp in length. This integron probably arose by homologous recombination since it was embedded in a hybrid Tn21-like transposon backbone which comprised a Tn5036-like tnp transposition module at the IRi integron end and a Tn21 mer module at the IRt integron end. The parent integron/transposon that contributed the Tn5036 module was not related to Tn1696 since the integron insertion points in the transposon backbones were 16 bases apart. Examination of the other 20 class 1 integron-containing strains revealed further evidence of genetic exchange. This included a strain that possessed a Tn5036 module at the IRt end but not at the IRi end and another that possessed a tnp module beyond IRi that was a hybrid of Tn21 and Tn5051 and that is presumed to have arisen by site-specific recombination. This study highlights the ability of different genetic elements to act cooperatively to spread and rearrange antibiotic resistance in a community.

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Section: Resultsmentioning

confidence: 99%

Urinary Tract Infections in a South American Population: Dynamic Spread of Class 1 Integrons and Multidrug Resistance by Homologous and Site-Specific Recombination

et al. 2008

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“…There is substantial evidence linking the origin of a subset of these resistance genes to the chromosomes of environmental bacteria (1,86,103), and there is considerable circumstantial evidence that CR elements are responsible for the mobility and dissemination of many genes (23,107). CRs have also been implicated in the construction of the multidrug resistance (MDR) regions of the integrative conjugative element SXT and the Salmonella genomic island 1 (SGI1) and their variants (4,15).…”

Section: Crs and Their Discoverymentioning

confidence: 99%

IS CR Elements: Novel Gene-Capturing Systems of the 21st Century?

Toleman

Bennett

Walsh

2006

Microbiol Mol Biol Rev

528

481

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SUMMARY “Common regions” (CRs), such as Orf513, are being increasingly linked to mega-antibiotic-resistant regions. While their overall nucleotide sequences show little identity to other mobile elements, amino acid alignments indicate that they possess the key motifs of IS91-like elements, which have been linked to the mobility ent plasmids in pathogenic Escherichia coli. Further inspection reveals that they possess an IS91-like origin of replication and termination sites (terIS), and therefore CRs probably transpose via a rolling-circle replication mechanism. Accordingly, in this review we have renamed CRs as ISCRs to give a more accurate reflection of their functional properties. The genetic context surrounding ISCRs indicates that they can procure 5′ sequences via misreading of the cognate terIS, i.e., “unchecked transposition.” Clinically, the most worrying aspect of ISCRs is that they are increasingly being linked with more potent examples of resistance, i.e., metallo-β-lactamases in Pseudomonas aeruginosa and co-trimoxazole resistance in Stenotrophomonas maltophilia. Furthermore, if ISCR elements do move via “unchecked RC transposition,” as has been speculated for ISCR1, then this mechanism provides antibiotic resistance genes with a highly mobile genetic vehicle that could greatly exceed the effects of previously reported mobile genetic mechanisms. It has been hypothesized that bacteria will surprise us by extending their “genetic construction kit” to procure and evince additional DNA and, therefore, antibiotic resistance genes. It appears that ISCR elements have now firmly established themselves within that regimen.

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“…Two of them (bla CTX-M-2 and bla CTX-M-9 ) were found to be associated with complex class 1 integrons related to In6 and In7, although they are not found on typical gene cassettes (1,10,23).…”

mentioning

confidence: 99%

Multiple CTX-M-Type Extended-Spectrum β-Lactamases in Nosocomial Isolates of Enterobacteriaceae from a Hospital in Northern Italy

et al. 2003

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Twelve isolates of Enterobacteriaceae (1 of Klebsiella pneumoniae, 8 of Escherichia coli, 1 of Proteus mirabilis, and 2 of Proteus vulgaris) classified as extended-spectrum ␤-lactamase (ESBL) producers according to the ESBL screen flow application of the BD-Phoenix automatic system and for which the cefotaxime MICs were higher than those of ceftazidime were collected between January 2001 and July 2002 at the Laboratory of Clinical Microbiology of the San Matteo University Hospital of Pavia (northern Italy). By PCR and sequencing, a CTX-M-type determinant was detected in six isolates, including three of E. coli (carrying bla CTX-M-1 ), two of P. vulgaris (carrying bla CTX-M-2 ), and one of K. pneumoniae (carrying bla CTX-M-15 ). The three CTX-M-1-producing E. coli isolates were from different wards, and genotyping by pulsed-field gel electrophoresis (PFGE) revealed that they were clonally unrelated to each other. The two CTX-M-2-producing P. vulgaris isolates were from the same ward (although isolated several months apart), and PFGE analysis revealed probable clonal relatedness. The bla CTX-M-1 and bla CTX-M-2 determinants were transferable to E. coli by conjugation, while conjugative transfer of the bla CTX-M-15 determinant from K. pneumoniae was not detectable. Present findings indicate that CTX-M enzymes of various types are present also in Italy and underscore that different CTX-M determinants can be found in a single hospital and can show different dissemination patterns. This is also the first report of CTX-M-2 in P. vulgaris.The CTX-M-type enzymes are a group of molecular class A extended-spectrum ␤-lactamases (ESBLs) that exhibit an overall preference for cefotaxime (CTX; hence the CTX-M name) and ceftriaxone and a higher susceptibility to tazobactam than to clavulanate. These enzymes are emerging in members of the family Enterobacteriaceae, where they can cause resistance to CTX and other expanded-spectrum ␤-lactams (7, 28).

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bla _CTX-M-2 Is Located in an Unusual Class 1 Integron (In35) Which Includes Orf513

Cited by 96 publications

References 19 publications

Urinary Tract Infections in a South American Population: Dynamic Spread of Class 1 Integrons and Multidrug Resistance by Homologous and Site-Specific Recombination

Urinary Tract Infections in a South American Population: Dynamic Spread of Class 1 Integrons and Multidrug Resistance by Homologous and Site-Specific Recombination

IS CR Elements: Novel Gene-Capturing Systems of the 21st Century?

Multiple CTX-M-Type Extended-Spectrum β-Lactamases in Nosocomial Isolates of Enterobacteriaceae from a Hospital in Northern Italy

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bla CTX-M-2 Is Located in an Unusual Class 1 Integron (In35) Which Includes Orf513

Cited by 96 publications

References 19 publications

Urinary Tract Infections in a South American Population: Dynamic Spread of Class 1 Integrons and Multidrug Resistance by Homologous and Site-Specific Recombination

Urinary Tract Infections in a South American Population: Dynamic Spread of Class 1 Integrons and Multidrug Resistance by Homologous and Site-Specific Recombination

IS CR Elements: Novel Gene-Capturing Systems of the 21st Century?

Multiple CTX-M-Type Extended-Spectrum β-Lactamases in Nosocomial Isolates of Enterobacteriaceae from a Hospital in Northern Italy

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Product

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bla _CTX-M-2 Is Located in an Unusual Class 1 Integron (In35) Which Includes Orf513