Objectives: To determine the rate of Staphylococcus aureus faecal carriage in 101 wild small mammals in Spain and to characterize the isolates obtained.
Methods: Faecal samples were seeded on mannitol salt agar and ORSAB plates. The presence of the resistance genes mecA, mecC and blaZ and the new blaZ allotype associated with staphylococcal cassette chromosome mec (SCCmec) XI (blaZ-SCCmecXI) was studied by PCR. S. aureus isolates were characterized by spa typing, agr typing and multilocus sequence typing. The presence of immune evasion cluster (IEC) genes and virulence genes was analysed by PCR.
Results: S. aureus was detected in 13/101 studied faecal samples and one isolate per positive sample was further studied. Two S. aureus isolates were methicillin-resistant S. aureus (MRSA) (recovered from wood mice, Apodemus sylvaticus) and 11 were methicillin-susceptible S. aureus (MSSA). Both MRSA isolates harboured the mecC gene and the novel blaZ-SCCmecXI, were typed as spa-t1535/agrIII/ST1945(CC130)/SCCmecXI (where ST stands for sequence type and CC stands for clonal complex), carried the exfoliative toxin etd2 gene and were IEC type E. Eight different spa types were identified among the 11 MSSA isolates (five new) and six different sequence types were identified (two new). All MSSA strains were susceptible to the antibiotics tested except one blaZ-positive penicillin-resistant isolate (spa-t120/agrII/ST15). MSSA isolates were ascribed to the CCs (number of strains) CC5 (1), CC1956 (4) and singleton (6). Nine of 11 MSSA isolates carried the cna virulence gene. Only one MSSA isolate carried IEC genes (type C).
Conclusions: This is the first report of MRSA carrying mecC in faecal samples of wild small mammals in Spain. These resistant isolates carried genes of the IEC system, unusual in S. aureus from animals. Wild small mammals could be a reservoir of the mecC gene with important implications for public health.
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http://dx.doi.org/10.1093/jac/dku100 | DOI Listing |
J Extracell Vesicles
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IPMC, UMR7275 CNRS-UniCA, INSERM U1323, team certified "Laboratory of Excellence (LABEX) Distalz", Valbonne, France.
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January 2025
Key Laboratory of Green Chemistry & Technology of Ministry of Education, College of Chemistry, Sichuan University, Chengdu 610064, Sichuan, China.
Isothermal nucleic acid amplification techniques are promising alternatives to polymerase chain reaction (PCR) for amplifying and detecting nucleic acids under resource-limited conditions. While many isothermal amplification strategies, such as recombinase polymerase amplification (RPA), offer comparable sensitivity to PCR, they often lack the specificity and robustness for discriminating single nucleotide variants (SNVs), mainly due to the uncontrolled production of massive amplicons. Herein, we introduce a mismatch-guided DNA assembly (MGDA) approach capable of discriminating SNVs in the presence of high concentrations of wild-type (WT) interferences.
View Article and Find Full Text PDFBMC Plant Biol
January 2025
College of Life Science, Henan Agricultural University, Zhengzhou, China.
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January 2025
Shanghai Institute of Materia Medica Chinese Academy of Sciences, Chemical Biology Research Center, 201203, Shanghai, CHINA.
Aldolases are powerful C-C bond-forming enzymes for asymmetric organic synthesis because of their supreme stereoselectivity, diverse electrophiles and nucleophiles, and promising scalability. Stereodivergent engineering of aldolases to tune the selectivity for the synthesis of stereoisomers of chiral molecules is highly desirable but has rarely been reported. This study documented the semirational engineering of the decarboxylative aldolase UstD with the focused rational iterative site-specific mutagenesis (FRISM) strategy to perform a C-C bond-forming reaction with dione electrophiles.
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November 2024
CAS Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, Yunnan, PR China.
Genome skimming has dramatically extended DNA barcoding from short DNA fragments to next generation barcodes in plants. However, conserved DNA barcoding markers, including complete plastid genome and nuclear ribosomal DNA (nrDNA) sequences, are inadequate for accurate species identification. Skmer, a recently proposed approach that estimates genetic distances among species based on unassembled genome skims, has been proposed to effectively improve species discrimination rate.
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