Analysis of the β-lactamase plasmid of borderline methicillin-susceptible Staphylococcus aureus: Focus on bla complex genes and cadmium resistance determinants cadD and cadX

Massidda, Orietta; Mingoia, Marina; Fadda, Daniela; Whalen, Michael B.; Montanari, Maria Pia; Varaldo, Pietro E.

doi:10.1016/j.plasmid.2005.08.001

Cited by 39 publications

(30 citation statements)

References 38 publications

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“…Seven specimens generated false-negative results for MRSA on at least one of the molecular assays (Xpert MRSA/SA BC, n ϭ 2; GeneOhm, n ϭ 6). The possible causes for this include variant SCCmec cassettes, as previously discussed, the presence of the mecC resistance determinant, or high-level expression of penicillinases leading to borderline oxacillin resistance (31)(32)(33)(34). All strains were confirmed to be phenotypically methicillin resistant, demonstrating zones of inhibition ranging from undetectable to 14 mm with the cefoxitin disk diffusion test.…”

Section: Discussionmentioning

confidence: 80%

Comparison of the Next-Generation Xpert MRSA/SA BC Assay and the GeneOhm StaphSR Assay to Routine Culture for Identification of Staphylococcus aureus and Methicillin-Resistant S. aureus in Positive-Blood-Culture Broths

et al. 2015

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A bloodstream infection with Staphylococcus aureus, including methicillin-resistant S. aureus (MRSA), is a serious condition that carries a high mortality rate and is also associated with significant hospital costs. The rapid and accurate identification and differentiation of methicillin-susceptible S. aureus (MSSA) and MRSA directly from positive blood cultures has demonstrated benefits in both patient outcome and cost-of-care metrics. We compare the next-generation Xpert MRSA/SA BC (Xpert) assay to the GeneOhm StaphSR (GeneOhm) assay for the identification and detection of S. aureus and methicillin resistance in prospectively collected blood culture broths containing Gram-positive cocci. All results were compared to routine bacterial culture as the gold standard. Across 8 collection and test sites, the Xpert assay demonstrated a sensitivity of 99.6% (range, 96.4% to 100%) and a specificity of 99.5% (range, 98.0% to 100%) for identifying S. aureus, as well as a sensitivity of 98.1% (range, 87.5% to 100%) and a specificity of 99.6% (range, 98.3% to 100%) for identifying MRSA. In comparison, the GeneOhm assay demonstrated a sensitivity of 99.2% (range, 95.2% to 100%) and a specificity of 96.5% (range, 89.2% to 100%) for identifying S. aureus, as well as a sensitivity of 94.3% (range, 87.5% to 100%) and a specificity of 97.8% (range, 96.1% to 100%) for identifying MRSA. Five of six cultures falsely reported as negative for MRSA by the GeneOhm assay were correctly identified as positive by the Xpert assay, while one culture falsely reported as negative for MRSA by the Xpert assay was correctly reported as positive by the GeneOhm assay. Bloodstream infection (BSI) is a serious condition, resulting in Ͼ500,000 hospitalizations per year in the United States, accounting for up to 11% of intensive care unit admissions (1, 2). Mortality associated with BSI can range from 25% to 80%, depending on underlying illnesses, and it is higher in nosocomial versus community-acquired infections (3-5). Bloodstream infections also carry a high monetary burden, ranging from $36,000 to $40,000 in additional expenses per patient as a result of prolonged hospitalization (4-6). The leading causes of community-and hospital-acquired BSI are Staphylococcus aureus, Staphylococcus epidermidis, and various other coagulase-negative Staphylococcus (CoNS) species (5, 7). Within this group of organisms, infection with methicillin-resistant S. aureus (MRSA) is most critical and has been associated with a mortality rate 1.70 to 1.93 times higher than that of methicillin-susceptible S. aureus (MSSA) strains (8, 9). The outcome of these infections can be positively impacted by early diagnosis and effective antimicrobial therapy (10-12). Rapid diagnostic methods, such as peptide nucleic acid fluorescence in situ hybridization (PNA FISH), matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS), and nucleic acid amplification and detection have been successfully applied to directly analyze positive blood culture broths ...

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Section: Discussionmentioning

confidence: 80%

Comparison of the Next-Generation Xpert MRSA/SA BC Assay and the GeneOhm StaphSR Assay to Routine Culture for Identification of Staphylococcus aureus and Methicillin-Resistant S. aureus in Positive-Blood-Culture Broths

et al. 2015

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“…Resistance genes were detected by PCR. They included genes for penicillin resistance (53), tetracycline resistance (56), aminoglycoside resistance (9,11), macrolide and lincosamide resistance (51), chloramphenicol resistance (32), and cadmium resistance (cadDX [36]); for the detection of the other cadmium resistance genes (cadA and cadC), primer set cadA-F1 (5Ј-GTTCGATTGTAATTGGCGG) and cadA-R1 (5Ј-TTTCCTGACCATTC CGC) and primer set cadC-F1 (5Ј-GAAGATAAGGTAAACAGGGCT) and cadC-R1 (5Ј-CAAGCTGTTTAACATGCTC), respectively, were designed in this study on the basis of the gene sequences of MRSA strain 252 (GenBank accession no. BX571856).…”

Section: Methodsmentioning

confidence: 99%

Novel Characteristics of Community-Acquired Methicillin-Resistant Staphylococcus aureus Strains Belonging to Multilocus Sequence Type 59 in Taiwan

Takano

Higuchi

Otsuka

et al. 2008

Antimicrob Agents Chemother

150

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“…MICs were determined by broth microdilution as recommended by the Clinical and Laboratory Standards Institute (9). Susceptibility to cadmium sulfate (BDH Laboratory Supplies, Poole, United Kingdom) was determined by a spectrophotometric assay as described elsewhere (24).…”

Section: Methodsmentioning

confidence: 99%

Different Genetic Elements Carrying the tet (W) Gene in Two Human Clinical Isolates of Streptococcus suis

Palmieri

Princivalli

Brenciani

et al. 2011

Antimicrob Agents Chemother

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The genetic support for tet(W), an emerging tetracycline resistance determinant, was studied in two strains of Streptococcus suis, SsCA and SsUD, both isolated in Italy from patients with meningitis. Two completely different tet(W)-carrying genetic elements, sharing only a tet(W)-containing segment barely larger than the gene, were found in the two strains. The one from strain SsCA was nontransferable, and aside from an erm(B)-containing insertion, it closely resembled a genomic island recently described in an S. suis Chinese human isolate in sequence, organization, and chromosomal location. The tet(W)-carrying genetic element from strain SsUD was transferable (at a low frequency) and, though apparently noninducible following mitomycin C treatment, displayed a typical phage organization and was named ⌽SsUD.1. Its full sequence was determined (60,711 bp), the highest BLASTN score being Streptococcus pyogenes ⌽m46.1. ⌽SsUD.1 exhibited a unique combination of antibiotic and heavy metal resistance genes. Besides tet(W), it contained a MAS (macrolide-aminoglycoside-streptothricin) fragment with an erm(B) gene having a deleted leader peptide and a cadC/cadA cadmium efflux cassette. The MAS fragment closely resembled the one recently described in pneumococcal transposons Tn6003 and Tn1545. These resistance genes found in the ⌽SsUD.1 phage scaffold differed from, but were in the same position as, cargo genes carried by other streptococcal phages. The chromosome integration site of ⌽SsUD.1 was at the 3 end of a conserved tRNA uracil methyltransferase (rum) gene. This site, known to be an insertional hot spot for mobile elements in S. pyogenes, might play a similar role in S. suis. tet(W)is an emerging tetracycline resistance determinant whose host range, including Gram-positive, Gram-negative, aerobic, and anaerobic bacteria, is second only to that of tet(M) among ribosomal protection tet genes (26). tet(W) was first identified in the rumen anaerobe Butyrivibrio fibrisolvens (3), where it was associated with a transposable chromosomal element. It was subsequently detected in several other bacteria of the animal and human gastrointestinal tract, associated with either conjugative or nonconjugative elements (1, 5, 13, 14, 19, 29-31, 33, 37).In 2008 we first described tet(W) in Streptococcus suis, in a human isolate from a sporadic case of meningitis in Italy (23). S. suis, a major swine pathogen worldwide, is emerging as a zoonotic agent, the most common human clinical manifestations being meningitis and sepsis (20,39). Most cases of human S. suis infection have originated in Southeast Asia, where pig rearing is widespread, and large outbreaks have occurred in China (20). In industrialized countries human infections are rare, albeit probably underdiagnosed, and usually arise as sporadic cases. The growing interest in this emerging pathogen is reflected by recent whole-genome sequencing studies of selected isolates directed at elucidating the occurrence and evolution of the genetic determinants of its pathogenicity and dru...

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Analysis of the β-lactamase plasmid of borderline methicillin-susceptible Staphylococcus aureus: Focus on bla complex genes and cadmium resistance determinants cadD and cadX

Cited by 39 publications

References 38 publications

Comparison of the Next-Generation Xpert MRSA/SA BC Assay and the GeneOhm StaphSR Assay to Routine Culture for Identification of Staphylococcus aureus and Methicillin-Resistant S. aureus in Positive-Blood-Culture Broths

Comparison of the Next-Generation Xpert MRSA/SA BC Assay and the GeneOhm StaphSR Assay to Routine Culture for Identification of Staphylococcus aureus and Methicillin-Resistant S. aureus in Positive-Blood-Culture Broths

Novel Characteristics of Community-Acquired Methicillin-Resistant Staphylococcus aureus Strains Belonging to Multilocus Sequence Type 59 in Taiwan

Different Genetic Elements Carrying the tet (W) Gene in Two Human Clinical Isolates of Streptococcus suis

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