| Autor: |
Scharn CR; Department of Medical Microbiology and Immunology, Creighton University School of Medicine, Omaha, Nebraska, USA., Tickler IA; Cepheid, Sunnyvale, California, USA., Tenover FC; Cepheid, Sunnyvale, California, USA., Goering RV; Department of Medical Microbiology and Immunology, Creighton University School of Medicine, Omaha, Nebraska, USA. |
| Jazyk: |
angličtina |
| Zdroj: |
Antimicrobial agents and chemotherapy [Antimicrob Agents Chemother] 2022 Apr 19; Vol. 66 (4), pp. e0237421. Date of Electronic Publication: 2022 Mar 07. |
| DOI: |
10.1128/aac.02374-21 |
| Abstrakt: |
Staphylococcal cassette chromosome mec (SCC mec ) represents a sequence of clear clinical and diagnostic importance in staphylococci. At a minimum the chromosomal cassette contains the mecA gene encoding PBP2a but frequently also includes additional antibiotic resistance genes (e.g., ermA and aadC ; macrolide and aminoglycoside resistance, respectively). Certain regions within SCC mec elements are hot spots for sequence instability due to cassette-specific recombinases and a variety of internal mobile elements. SCC mec changes may affect not only cassette stability but the integrity of adjacent chromosomal sequences (e.g., the staphylococcal protein A gene; spa ). We investigated SCC mec stability in methicillin-resistant Staphylococcus aureus (MRSA) strains carrying one of four SCC mec types cultured in the absence of antimicrobial selection over a 3-month period. SCC mec rearrangements were first detected in cefoxitin-susceptible variants after 2 months of passage, and most commonly showed precise excision of the SCC mec element. Sequence analysis after 3 months revealed both precise SCC mec excision and a variety of SCC mec internal deletions, some including extensive adjacent chromosomal loss, including spa . No empty cassettes (i.e., loss of just mecA from SCC mec ) were observed among the variants. SCC mec stability was influenced both by internal mobile elements (IS 431 ) as well as the host cell environment. Genotypically similar clinical isolates with deletions in the spa gene were also included for purposes of comparison. The results indicate a role for host-cell influence and the IS 431 element on SCC mec stability. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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