Conjugal mobilization of the mega element carryingmef(E) fromStreptococcus salivariustoStreptococcus pneumoniae

Santagati, Maria; Lupo, Agnese; Scillato, Marina; Martino, Andrea Di; Stefani, Stefania

doi:10.1111/j.1574-6968.2008.01408.x

Cited by 11 publications

(8 citation statements)

References 36 publications

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“…This genetic element has been reported by Brenciani et al to be frequent in viridans group streptococci (15). It can contribute to the dissemination of erythromycin resistance genes, since conjugative mobilization of MEGA from viridans group streptococci to S. pyogenes and S. pneumoniae has been reported (51,52). Forty-six strains that harbor a MEGA element also carry a conjugative element related to ICESt3 or Tn916 that could participate in the conjugative mobilization of MEGA.…”

Section: Discussionmentioning

confidence: 99%

Resistance Genes and Genetic Elements Associated with Antibiotic Resistance in Clinical and Commensal Isolates of Streptococcus salivarius

Chaffanel

Charron-Bourgoin

Libante

et al. 2015

Appl Environ Microbiol

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The diversity of clinical (n ‫؍‬ 92) and oral and digestive commensal (n ‫؍‬ 120) isolates of Streptococcus salivarius was analyzed by multilocus sequence typing (MLST). No clustering of clinical or commensal strains can be observed in the phylogenetic tree. Selected strains (92 clinical and 46 commensal strains) were then examined for their susceptibilities to tetracyclines, macrolides, lincosamides, aminoglycosides, and phenicol antibiotics. The presence of resistance genes tet(M), tet(O), erm(A), erm(B), mef(A/ E), and catQ and associated genetic elements was investigated by PCR, as was the genetic linkage of resistance genes. High rates of erythromycin and tetracycline resistance were observed among the strains. Clinical strains displayed either the erm(B) (macrolide-lincosamide-streptogramin B [MLS B ] phenotype) or mef(A/E) (M phenotype) resistance determinant, whereas almost all the commensal strains harbored the mef(A/E) resistance gene, carried by a macrolide efflux genetic assembly (MEGA) element. A genetic linkage between a macrolide resistance gene and genes of Tn916 was detected in 23 clinical strains and 5 commensal strains, with a predominance of Tn3872 elements (n ‫؍‬ 13), followed by Tn6002 (n ‫؍‬ 11) and Tn2009 (n ‫؍‬ 4) elements. Four strains harboring a mef(A/E) gene were also resistant to chloramphenicol and carried a catQ gene. Sequencing of the genome of one of these strains revealed that these genes colocalized on an IQ-like element, as already described for other viridans group streptococci. ICESt3-related elements were also detected in half of the isolates. This work highlights the potential role of S. salivarius in the spread of antibiotic resistance genes both in the oral sphere and in the gut. Streptococcus salivarius is a Gram-positive commensal bacterium that is a major bacterial constituent of saliva and of biofilms found on the human tongue dorsum (1). It belongs to the early microbial community that colonizes the oral cavities of newborns (2) and persists in the adult oral flora (3). This species is considered to contribute to oral health by preventing the colonization of mucosal surfaces with pathogens involved in upper respiratory tract infections (4). For instance, S. salivarius strains have been reported to inhibit biofilm formation by Streptococcus pyogenes (5) and Streptococcus mutans (6) as well as adherence by Candida albicans (7). S. salivarius is also commonly detected as an inhabitant of the gastrointestinal tracts of healthy humans and has been described as a typical small intestine commensal species (8). However, some strains have been associated with opportunistic infections: a growing number of meningitis cases (9, 10), several cases of endocarditis (11), bacteremia in immunocompromised patients (12, 13), and invasion of the guts of patients with liver cirrhosis (14).Macrolides and tetracyclines are commonly used for the treatment of streptococcal infections, but high rates of resistance to these antibiotics have been observed among pathogenic and commensal strept...

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Section: Discussionmentioning

confidence: 99%

Resistance Genes and Genetic Elements Associated with Antibiotic Resistance in Clinical and Commensal Isolates of Streptococcus salivarius

Chaffanel

Charron-Bourgoin

Libante

et al. 2015

Appl Environ Microbiol

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“…This element, designated the 5216IQ complex of 30.5 kb, includes portions derived from Tn5252 and Tn916, genetic elements frequently found in S. pneumoniae, in association with a novel element enclosing mef(I) and catQ and designated the IQ element (17). Some elements, such as Tn1207.3 and ⌽m46.1 of S. pyogenes and mega of Streptococcus salivarius, are transferable by conjugation (22,23), while the mef-containing elements of S. pneumoniae appear to be nonconjugative.…”

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confidence: 99%

Genetic Resistance Elements Carrying mef Subclasses Other than mef (A) in Streptococcus pyogenes

Grosso

Camilli

Barbabella

et al. 2011

Antimicrob Agents Chemother

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In Streptococcus pyogenes, efflux-mediated erythromycin resistance is associated with the mef gene, represented mostly by mef(A), although a small portion of strains carry different mef subclasses. We characterized the composite genetic elements, including mef subclasses other than mef(A), associated with other resistance genes in S. pyogenes isolates. Determination of the genetic elements was performed by PCR mapping. The strains carrying mosaic mef(A/E), in which the 5 region was identical to mef(A) and the 3 region was identical to mef(E), also carried tet(O). The two genes were found enclosed in an element similar to S. pyogenes prophage ⌽m46.1, designated the ⌽m46.1-like element. In S. pyogenes strains carrying mef(E) and tet(M), mef(E) was included in a typical mega element, and in some strains, it was physically associated with tet(M) in the composite element Tn2009. S. pyogenes strains carrying mef(I) also carried catQ; the two genes were linked in a fragment representing a portion of the 5216IQ complex of Streptococcus pneumoniae, designated the defective IQ element. In the only isolate carrying a novel mef gene, this was associated with catQ and tet(M) in a genetic element similar to the 5216IQ complex of S. pneumoniae (5216IQ-like complex), suggesting that the novel mef is in fact a variant of mef(I). This study demonstrates that the composite elements containing mef are shared between S. pyogenes and S. pneumoniae and suggests that it is important to distinguish the mef subclass on the basis of the genetic element containing it.Efflux-mediated macrolide resistance in Streptococcus pyogenes and Streptococcus pneumoniae is conferred by mef and the adjacent msr(D) gene, which code for a two-component transport system (1). The resistance phenotype acquired by the microorganisms is defined as M, since the efflux mechanism confers resistance to macrolides only, as opposed to the MLS B phenotype (resistance to macrolides, lincosamides, and streptogramin B) conferred by the Erm methylase (16).Several allelic variants or subclasses of the mef gene have been described for S. pyogenes and S. pneumoniae, including the more common mef(A) and mef(E) and the rarely encountered mef(I) and mef(O) (3,15,17,20).Although the mef subclasses show a high level of identity at the nucleotide level (from 88% to 94%), each is found embedded in a different genetic element, suggesting a different evolutionary and transmission route (23). In S. pyogenes the most common mef subclass is mef(A) (5, 14), which is carried by two similar genetic elements: Tn1207.3, of approximately 52 kb, and ⌽10394.4, a prophage of approximately 59 kb (2, 21). In S. pneumoniae, mef(A) is carried by Tn1207.1, a defective element of 7.2 kb corresponding to the leftmost mef-containing region of Tn1207.3 (21). In S. pyogenes, a sequence similar to that of Tn1207.1 including mef(A) was found associated with tet(O) in ⌽m46.1, a prophage element of 55.1 kb, also present as a free circular form in the bacterial culture (4).The mef(E) subclass is common in S. ...

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“…Cultures were incubated overnight at 37°C in 5% CO 2 in air atmosphere. A total of 81 a-haemolytic streptococci were isolated and identified by API Strep and sequencing of 16S rRNA gene and the sodA gene encoding for superoxide dismutase and used for correct speciation (Santagati et al, 2009;Teles et al, 2011).…”

Section: Methodsmentioning

confidence: 99%

“…Total bacterial DNA was extracted in agarose plugs as described before (Santagati et al, 2009). After digestion with the SacII enzyme (TaKaRa BIO), macro-restriction fragments were resolved in a 1% agarose gel using 0.59 tris-borate-ethylene diamine tetra-acetic acid buffer (BioRad) at 14°C.…”

Section: Pulsed-field-gel-electrophoresis and Dna Hybridizationmentioning

confidence: 99%

“…Genes responsible for bacteriocin production (salA, sboB, sivA, srtA, scnA, nisA, nisF, nsuB, mutII, mutIII, srtF, lanB, and lanC) were amplified by PCR using primers previously published (Hynes et al, 1993;Karaya et al, 2001;Upton et al, 2001;Wescombe et al, 2006;Wirawan et al, 2006) and those designed for this study see Table 1. For mef(E) detection and PCR, we used previously published protocols (Santagati et al, 2009).…”

Section: Detection Of Bacteriocin-encoding Genesmentioning

confidence: 99%

See 1 more Smart Citation

Bacteriocin-producing oral streptococci and inhibition of respiratory pathogens

Santagati

Scillato

Patanè

et al. 2012

FEMS Immunol Med Microbiol

Self Cite

126

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The use of bacteria as probiotics is in continuous development, thanks to their capacity to maintain or restore a host's natural microbiome by interference with and/or inhibition of other microorganisms mediated by antimicrobial peptide production such as bacteriocins. In the oral cavity, Streptococcus salivarius, a non-pathogenic and predominant oral species, is one of the major bacteriocin producers that is able to coexist in this environment and reduce the frequency of colonization of the main pathogens involved in upper respiratory tract infections. The aim of this study was to screen oral bacteria colonizing healthy children for their use as potential oral probiotics. Eighty-one α-hemolytic streptococci isolated from nasal and/or pharyngeal swabs of 31 healthy children aged between two and twelve years were isolated. Among them, 13 α-hemolytic streptococci were selected for their bacteriocin-like inhibitory activity against potential pathogens. These strains were tested for bacteriocin production and assayed for their capacity to adhere to HEp-2 cell lines. Our data showed that 13 bacteriocin producer strains were able to inhibit different gram-positive pathogens. Among them one strain, S. salivarius 24SMB, deposited as DSM 23307, was selected as a potential oral probiotic, thanks to its safety assessment, ability to inhibit Streptococcus pneumoniae and the absence of virulence and antibiotic resistance genes.

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Conjugal mobilization of the mega element carryingmef(E) fromStreptococcus salivariustoStreptococcus pneumoniae

Cited by 11 publications

References 36 publications

Resistance Genes and Genetic Elements Associated with Antibiotic Resistance in Clinical and Commensal Isolates of Streptococcus salivarius

Resistance Genes and Genetic Elements Associated with Antibiotic Resistance in Clinical and Commensal Isolates of Streptococcus salivarius

Genetic Resistance Elements Carrying mef Subclasses Other than mef (A) in Streptococcus pyogenes

Bacteriocin-producing oral streptococci and inhibition of respiratory pathogens

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