Characterization of staphylococcal cassette chromosome mec in Staphylococcus haemolyticus ST3 and ST42 isolates from bovine mastitis milk: identification of novel variant in class C1 mec complex
Issued Date
2024-10-01
Resource Type
eISSN
14602091
Scopus ID
2-s2.0-85205524846
Pubmed ID
39082161
Journal Title
The Journal of antimicrobial chemotherapy
Volume
79
Issue
10
Start Page
2479
End Page
2483
Rights Holder(s)
SCOPUS
Bibliographic Citation
The Journal of antimicrobial chemotherapy Vol.79 No.10 (2024) , 2479-2483
Suggested Citation
Thanasak J., Wongsurawat T., Jenjaroenpun P., Phumthanakorn N. Characterization of staphylococcal cassette chromosome mec in Staphylococcus haemolyticus ST3 and ST42 isolates from bovine mastitis milk: identification of novel variant in class C1 mec complex. The Journal of antimicrobial chemotherapy Vol.79 No.10 (2024) , 2479-2483. 2483. doi:10.1093/jac/dkae242 Retrieved from: https://repository.li.mahidol.ac.th/handle/20.500.14594/101579
Title
Characterization of staphylococcal cassette chromosome mec in Staphylococcus haemolyticus ST3 and ST42 isolates from bovine mastitis milk: identification of novel variant in class C1 mec complex
Author's Affiliation
Corresponding Author(s)
Other Contributor(s)
Abstract
BACKGROUND: Methicillin-resistant Staphylococcus haemolyticus (MRSH) is an important pathogenic agent of bovine mastitis. Among the prominent clone lineages in dairy cows are MRSH sequence types ST3 and ST42. Little information is available on the complete characterization of SCCmec elements in MRSH. OBJECTIVE: In this study, two clinical isolates of MRSH ST3 and ST42 from bovine mastitis milk were selected, and their nontypable SCCmec structures were compared. METHODS: Two MRSH strains, MRSH-ST3 strain M62.3 and MRSH-ST42 strain M81.1, were identified from bovine mastitis milk in Thailand in 2022. Minimum inhibitory concentration was used to screen for antimicrobial resistance susceptibility. Oxford Nanopore Technologies and Illumina sequencing were performed in combination to complete the genome. Their gene organization and structure of SCCmec types were analysed and compared with the whole sequences of other strains in the same sequence types. RESULTS: Both MRSH-ST3 strain M62.3 and MRSH-ST42 strain M81.1 possessed the class C1 mec complex but lacked the ccr gene complex. Notably, MRSH-ST42 strain M81.1 contained a novel variant of C1 mec complex, which consisted of IS431-mecA-ISSha1-paaZ-upgQ-IS431, with IS431 organized in the same orientation. Apart from class C1 mec and the heavy metal-resistant cluster, the gene composition and order of the SCCmec element varied. In ST3, variations in the SCCmec type, gene content and organization were observed. CONCLUSIONS: The distinct evolution of the MRSH lineage was indicated by the various SCCmec elements. The insertion of ISSha1 resulted in a unique variant of class C1 mec complex that demonstrated the important role of the insertion sequence in SCCmec diversification.