Integrons as tools for epidemiological studies

Severino, Patrícia; Magalhães, Vanda D.

doi:10.1111/j.1469-0691.2004.00769.x

Cited by 20 publications

(20 citation statements)

References 42 publications

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“…Although at least six classes of integron have been described (13,20), class 1 integrons are by far the most common in clinical isolates of gram-negative bacteria (16), including acinetobacters (12,15,23). Class 2 integrons have been found in Acinetobacter species (15,21) but are rare.…”

Section: Discussionmentioning

confidence: 99%

Detection and Typing of Integrons in Epidemic Strains of Acinetobacter baumannii Found in the United Kingdom

Turton¹,

Kaufmann²,

Glover³

et al. 2005

J Clin Microbiol

135

118

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Integrons were sought in Acinetobacter isolates from hospitals in the United Kingdom by integrase gene PCR. Isolates were compared by pulsed-field gel electrophoresis, and most belonged to a small number of outbreak strains or clones of A. baumannii, which are highly successful in the United Kingdom. Class 1 integrons were found in all of the outbreak isolates but in none of the sporadic isolates. No class 2 integrons were found. Three integrons were identified among the main outbreak strains and clones. While a particular integron was usually associated with a strain or clone, some members carried a different integron. Some integrons were associated with more than one strain. The cassette arrays of two of the integrons were very similar, both containing gene aacC1, which confers resistance to gentamicin, two open reading frames coding for unknown products (orfX, orfX), and gene aadA1a, which confers resistance to spectinomycin and streptomycin. The larger of these integrons had two copies of the first (orfX) of the gene cassettes coding for unknown products. The third integron, with a cassette array containing gene aacA4, which codes for amikacin, netilmicin, and tobramycin resistance; a chloramphenicol acetyltransferase, catB8; and gene aadA1, conferring resistance to spectinomycin and streptomycin, was associated with an OXA-23 carbapenemase-producing clone, which has spread rapidly in hospitals in the United Kingdom during 2003 and 2004. These integron cassette arrays have been found in other outbreak strains of A. baumannii from other countries. We conclude that integrons are useful markers for epidemic strains of A. baumannii and that integron typing provides valuable information for epidemiological studies.

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Section: Discussionmentioning

confidence: 99%

Detection and Typing of Integrons in Epidemic Strains of Acinetobacter baumannii Found in the United Kingdom

Turton¹,

Kaufmann²,

Glover³

et al. 2005

J Clin Microbiol

135

118

View full text Add to dashboard Cite

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“…This arrangement has been used as a polymerase chain reaction (PCR) tool for the simple recovery of cassette arrays irrespective of knowledge of the many and varied cassettes that may be present [11,12]. In addition to recovering and analysing cassettes from specific isolates, PCR has also been used as a tool in broader epidemiological studies [13]. However, this method has some limitations.…”

Section: Introductionmentioning

confidence: 99%

Class 1 integrons in environmental and clinical isolates of Pseudomonas aeruginosa

Ruiz-Martínez

López-Jiménez

Fusté

et al. 2011

International Journal of Antimicrobial Agents

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The aims of this study were to ascertain the presence and spread of class 1 integrons among environmental and clinical isolates of Pseudomonas aeruginosa and to characterise their variable regions. A total of 76 isolates (56 clinical and 20 environmental) were studied. The presence of plasmids was explored, and polymerase chain reaction (PCR) was used for integron detection. All amplicons were sequenced. PCR detected class 1 integrons in 26 of the 56 clinical isolates; environmental isolates were integron-free. No plasmids were found, thus all the integrons found are possibly on the chromosome. Most isolates presented one amplicon, except PA110514 and PA116136, which showed two PCR products each.Variable regions revealed that 18 strains carried only one gene involved in aminoglycoside resistance, whereas in 3 strains gene cassettes were not found. The most prevalent cassettes among isolates were those encoding aminoglycoside adenyltransferase B (aadB). Several of the strains had acquired the same or a highly similar cassette array as those detected in geographically distant P. aeruginosa. This finding suggests that contact with bacterial reservoirs contributes to the evolution of this pathogen towards multiresistance. Empty structures found may represent a reservoir increasing the capacity to adapt to the environment. However, these integrons are not retained when the selective pressure disappears. It is hypothesised that integrons containing gene cassettes are crucial vehicles for the rapid horizontal transfer of resistance. If this is so, reduced use of antibiotics may lead to a significant decrease in the carriage of integrons among P. aeruginosa strains.

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“…This arrangement has been used as a PCR tool for the simple recovery of cassette arrays irrespective of knowledge of the many and varied cassettes that may be present (24,36). As well as being able to recover and analyze cassettes from specific isolates, this method has also been used as a tool in broader epidemiological studies (19,38). The use of PCR for array analysis in the latter type of studies, however, has limitations.…”

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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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Integrons as tools for epidemiological studies

Cited by 20 publications

References 42 publications

Detection and Typing of Integrons in Epidemic Strains of Acinetobacter baumannii Found in the United Kingdom

Detection and Typing of Integrons in Epidemic Strains of Acinetobacter baumannii Found in the United Kingdom

Class 1 integrons in environmental and clinical isolates of Pseudomonas aeruginosa

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

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