Molecular analysis of multiresistant porcine Salmonella enterica subsp. enterica serovar Bredeney isolates from Southern Brazil: identification of resistance genes, integrons and a group II intron

Michael, Geovana Brenner; Cardoso, Marisa Ribeiro de Itapema; Schwarz, Štefan

doi:10.1016/j.ijantimicag.2008.02.024

Cited by 30 publications

(25 citation statements)

References 34 publications

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“…Class 2 integron had been widely distributed in Salmonella, especially in S. enterica (serovar Virchow and serovar Bredeney), S. Enteritidis and S. Typhimurium (Rodriguez et al, 2006, Michael et al,2008. Goldstein et al reported an occurrence of 5% (7/129) in Salmonella isolates (Goldstein et al, 2001).…”

Section: Class 2 Integronmentioning

confidence: 99%

Role of integrons in antimicrobial resistance: A review

Gao¹,

Li²,

Liu³

et al. 2013

Afr. J. Microbiol. Res.

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Antibiotic resistance in bacteria still remains one of the leading concerns in global public health. Horizontal transfer of resistance genes is considered to be a major cause to facilitate the rapid spread of antibiotic resistance in microbes. In recent years, the role of integrons as mobile genetic elements playing a central role in horizontal transfer of antibiotic resistance have been well studied and documented. Nevertheless, up to date, most of the available investigations and studies on integron had focused on class 1 integrons of Gram-negative microorganisms. In the last decade, class 4 integrons (also known as super integrons) has been considered a major concern in antimicrobial resistance, as well as, a significant factor in bacterial genome evolution; however, most reports had been limited to Vibrio. Thus, this review is aimed at summarizing the occurrence and prevalence of integrons in bacterial isolates, with the focus on class 1 integron within Gram-positive bacteria, class 2 and 3 integrons.

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Section: Class 2 Integronmentioning

confidence: 99%

Role of integrons in antimicrobial resistance: A review

Gao¹,

Li²,

Liu³

et al. 2013

Afr. J. Microbiol. Res.

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“…Most of the clinical isolates of ␤-lactamase-producing Salmonella synthesize class A ␤-lactamases (4), and the occurrence of isolates carrying plasmidic class C ␤-lactamases has also been reported worldwide (5,6). Regarding class D ␤-lactamases, only a few variants have been reported in Salmonella serotypes (e.g., OXA-1, -2, -53, -129, and -48) (7,8,9). In addition, the occurrence of metallo-␤-lactamase (MBL)-producing salmonellae is an infrequent event.…”

mentioning

confidence: 99%

Synthesis of Metallo-β-Lactamase VIM-2 Is Associated with a Fitness Reduction in Salmonella enterica Serovar Typhimurium

Cordeiro

Chabalgoity

Yim

et al. 2014

Antimicrob Agents Chemother

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Antibiotic resistance, especially due to ␤-lactamases, has become one of the main obstacles in the correct treatment of Salmonella infections; furthermore, antibiotic resistance determines a gain of function that may encompass a biological cost, or fitness reduction, to the resistant bacteria. The aim of this work was to determine in vitro if the production of the class B ␤-lactamase VIM-2 determined a fitness cost for Salmonella enterica serovar Typhimurium. To that end the gene bla VIM-2 was cloned into the virulent strain S. Typhimurium SL1344, using both the tightly regulated pBAD22 vector and the natural plasmid pST12, for inducible and constitutive expression, respectively. Fitness studies were performed by means of motility, growth rate, invasiveness in epithelial cells, and plasmid stability. The expression of bla VIM-2 was accompanied by alterations in micro-and macroscopic morphology and reduced growth rate and motility, as well as diminished invasiveness in epithelial cells. These results suggest that VIM-2 production entails a substantial fitness cost for S. Typhimurium, which in turn may account for the extremely low number of reports of metallo-␤-lactamase-producing Salmonella spp.

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“…The idea of reverse transcription became plausible when it was reported that a group IIC intron identified as Serratia marcescens I2 (S.ma.I2) was inserted into a mobile integron between a structural gene and its associated attC site in the multiresistant Serratia marcescens SCH909 strain (1). Since then, a specific lineage of several group IIC introns, named the group IIC-attC introns, has been identified inside cassettes of mobile or chromosomal integrons (22,26,32,47,51) or adjacent to isolated attC sites (18, 32). Group II introns are catalytic RNAs and mobile retroelements that self-splice (41).…”

mentioning

confidence: 99%

Group IIC Intron with an Unusual Target of Integration in Enterobacter cloacae

Rodríguez-Martínez

Nordmann

Poirel

2011

Journal of Bacteriology

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A potential role of group IIC-attC introns in integron gene cassette formation, that is, the way in which they could provide the attC sequence essential for recombination, has been proposed. Group IIC introns usually target the attC site of gene cassettes and more specifically their inverse core. Here we characterized a novel group IIC intron targeting the core site of the aadA1 gene cassette attC site (aadA1-qacE⌬1 gene cassette junction) from enterobacterial isolates. Intron mobility (retrohoming) was analyzed using a two-plasmid assay performed in Escherichia coli. Intron mobility assays confirmed the mobilization-integration of the group II intron into the core site of the aadA2, bla VIM-2 , bla CARB-2 , aac(6=)-Ib, dfrXVb, arr2, cmlA4, and aadB gene cassettes but not into the attI site. This mobility was dependent on maturase activity. Reverse transcriptase PCR showed that this intron was transcriptionally active, and an intermediate circular form was detected by inverse PCR. This element was linked to the bla VEB-1 extended-spectrum ␤-lactamase gene in a high number of enterobacterial isolates. A phylogenetic tree showed that the identified element was located in a branch separate from group IIC-attC introns, being an IIC intron possessing the ability to integrate using the core site of the attC sites as target. Integrons play an important role in the development of antibiotic resistance in Gram-negative pathogens. Class 1 and class 2 integrons have a worldwide distribution and are described from bacteria colonizing humans, animals, and farmed fish (6,19,21,45). In particular, class 1 integrons are increasingly reported to be a source of diffusion and expression of antibiotic resistance genes in Gram-negative bacteria, but the way in which they are built remains largely unknown (5). Their prevalence is increasing, in particular, in clinical enterobacterial isolates, playing a major role in the overall increased rate of antibiotic resistance worldwide (5, 42). The backbone structure of an integron contains a conserved region encoding an integrase (intI) and a variable region with integrated gene cassettes (45). A gene cassette usually contains a single open reading frame (ORF) and a recombination site, the attC site. The attC sites consist of an inverse core site and a core site separated by an imperfect intervening palindrome of variable length. The inverse core site is defined as RYYYAAC, and the core site is defined as GTTRRRY (10,45,46). The attC sites can vary in length (57 to 141 bp), and their sequence similarities are primarily restricted to the boundaries, which correspond to two pairs of conserved inverted repeats, 1L-2L and 2R-1R (46). It has been proposed that the coding DNA and the attC site originally had separate origins and that these elements have been joined through a specific assembly process (34, 38). Considering the unique structural characteristics of most integron cassettes (i.e., the absence of promoters, the paucity of noncoding sequence, and the presence of only one gene), it has b...

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Molecular analysis of multiresistant porcine Salmonella enterica subsp. enterica serovar Bredeney isolates from Southern Brazil: identification of resistance genes, integrons and a group II intron

Cited by 30 publications

References 34 publications

Role of integrons in antimicrobial resistance: A review

Role of integrons in antimicrobial resistance: A review

Synthesis of Metallo-β-Lactamase VIM-2 Is Associated with a Fitness Reduction in Salmonella enterica Serovar Typhimurium

Group IIC Intron with an Unusual Target of Integration in Enterobacter cloacae

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