Novel Type XII Staphylococcal Cassette Chromosome mec Harboring a New Cassette Chromosome Recombinase, CcrC2

• Published in: Antimicrobial agents and chemotherapy 2015-12, Vol.59 (12), p.7597-7601
• Main Authors: Wu, Zhaowei, Li, Fan, Liu, Dongliang, Xue, Huping, Zhao, Xin
• Format: Article
• Language: English
• Subjects: Animals; Anti-Bacterial Agents - pharmacology; Bacterial Proteins; Bacterial Proteins - genetics; Bacterial Proteins - metabolism; Cattle; Chromosome Mapping; Chromosomes, Bacterial - chemistry; Chromosomes, Bacterial - metabolism; DNA, Bacterial; DNA, Bacterial - genetics; DNA, Bacterial - metabolism; DNA, Circular - genetics; DNA, Circular - metabolism; Female; Gene Expression; Genotype; Mastitis - drug therapy; Mastitis - microbiology; Mechanisms of Resistance; Methicillin - pharmacology; Methicillin Resistance; Methicillin Resistance - genetics; Methicillin-Resistant Staphylococcus aureus; Methicillin-Resistant Staphylococcus aureus - classification; Methicillin-Resistant Staphylococcus aureus - enzymology; Methicillin-Resistant Staphylococcus aureus - genetics; Methicillin-Resistant Staphylococcus aureus - isolation & purification; Milk; Milk - microbiology; Recombinases; Recombinases - genetics; Recombinases - metabolism; Staphylococcal Infections - drug therapy; Staphylococcal Infections - microbiology; Staphylococcus aureus
• ISSN: 0066-4804; 1098-6596
• DOI: 10.1128/AAC.01692-15

Excision and integration of staphylococcal cassette chromosome mec (SCCmec) are mediated by cassette chromosome recombinases (Ccr), which play a crucial role in the worldwide spread of methicillin resistance in staphylococci. We report a novel ccr gene, ccrC2, in the SCCmec of a Staphylococcus aureus isolate, BA01611, which showed 62.6% to 69.4% sequence identities to all published ccrC1 sequences. A further survey found that the ccrC2 gene was mainly located among coagulase-negative staphylococci (CoNS) and could be found in staphylococcal isolates from China, the United States, France, and Germany. The ccr gene complex harboring the ccrC2 gene was designated a type 9 complex, and the SCCmec of BA01611 was considered a novel type and was designated type XII (9C2). This novel SCCmec element in BA01611 was flanked by a pseudo-SCC element (ΨSCCBA01611) carrying a truncated ccrA1 gene. Both individual SCC elements and a composite SCC were excised from the chromosome based on detection of extrachromosomal circular intermediates. We advocate inclusion of the ccrC2 gene and type 9 ccr gene complex during revision of the SCCmec typing method.