Genomic Basis of Occurrence of Cryptic Resistance among Oxacillin- and Cefoxitin-Susceptible mecA-Positive Staphylococcus aureus
ABSTRACT The oxacillin– and cefoxitin-susceptible mecA–positive Staphylococcus aureus is a novel “stealth” methicillin-resistant S. aureus (MRSA) type. Here, we sequenced the whole genome of two oxacillin- and cefoxitin-susceptible mecA-positive MRSA isolates from breast abscesses in a lactating wom...
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| Format: | Article |
| Language: | English |
| Published: |
American Society for Microbiology
2022-06-01
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| Series: | Microbiology Spectrum |
| Subjects: | |
| Online Access: | https://journals.asm.org/doi/10.1128/spectrum.00291-22 |
| _version_ | 1818255533438664704 |
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| author | Bingshao Liang Zhile Xiong Zhuwei Liang Chao Zhang Hao Cai Yan Long Fei Gao Jielin Wang Qiulian Deng Huamin Zhong Yongqiang Xie Lianfen Huang Sitang Gong Zhenwen Zhou |
| author_facet | Bingshao Liang Zhile Xiong Zhuwei Liang Chao Zhang Hao Cai Yan Long Fei Gao Jielin Wang Qiulian Deng Huamin Zhong Yongqiang Xie Lianfen Huang Sitang Gong Zhenwen Zhou |
| author_sort | Bingshao Liang |
| collection | DOAJ |
| description | ABSTRACT The oxacillin– and cefoxitin-susceptible mecA–positive Staphylococcus aureus is a novel “stealth” methicillin-resistant S. aureus (MRSA) type. Here, we sequenced the whole genome of two oxacillin- and cefoxitin-susceptible mecA-positive MRSA isolates from breast abscesses in a lactating woman and a nasal swab of a healthy student in Guangzhou for investigating the mechanism underlying its occurrence. The reversion of these isolates was selected by exposure to sub-MICs of cefoxitin with or without mupirocin. The mecA expression of both parental strains and their revertants was determined, and the whole genome of the revertants was sequenced. Comparative whole-genome analyses performed for both strains revealed that mecA of the clinical strain was mutated by a single-bp insertion at the 262nd position in the tandem repeat region of the gene, and this mutation that led to the formation of a premature stop codon. The colonizing strain was mutated by a novel G-to-A base substitution in the second promoter region (–35 bp) of mecA. The mecA expression level of strain 697 revertant was 37 times higher than that of the parental strain. Although the mecA expression level was even higher for parental strain 199 compared with that for its revertant, its cDNA sequence contained a single-bp insertion. Collectively, both the missense and single substitution mutations of the second promoter of mecA could render MRSA isolates as “stealth” MRSA, thereby emphasizing the importance of combining phenotype tests with mecA or penicillin-binding protein 2a detection for the identification of MRSA. IMPORTANCE The oxacillin- and cefoxitin-susceptible mecA-positive Staphylococcus aureus is a novel type of “stealth” methicillin-resistant S. aureus (MRSA), which is difficult to be detected using conventional methods. To investigate the genomic basis of their occurrence, we sequenced the whole genome of two previously recovered oxacillin- and cefoxitin-susceptible mecA-positive MRSA isolates from breast abscesses in a lactating woman and a nasal swab of a healthy student in Guangzhou. Complete SCCmec structure was absent except for mecA in clinical isolate 199. Additionally, a novel single-base pair insertion was observed in the clinical strain, which resulted in premature termination and a frameshift mutation. The colonizing isolate 697 had a Scc-mec-type IVa, and the second promoter region (–35 bp) of mecA was mutated by a novel G-to-A base substitution. The reversion of oxacillin- and cefoxitin-susceptible mecA-positive S. aureus to resistant MRSA isolates was selected by exposure to subminimum inhibitory cefoxitin with or without mupirocin. |
| first_indexed | 2024-12-12T17:13:22Z |
| format | Article |
| id | doaj.art-56bd46769056487e9a9acd02d1cf5214 |
| institution | Directory Open Access Journal |
| issn | 2165-0497 |
| language | English |
| last_indexed | 2024-12-12T17:13:22Z |
| publishDate | 2022-06-01 |
| publisher | American Society for Microbiology |
| record_format | Article |
| series | Microbiology Spectrum |
| spelling | doaj.art-56bd46769056487e9a9acd02d1cf52142022-12-22T00:17:50ZengAmerican Society for MicrobiologyMicrobiology Spectrum2165-04972022-06-0110310.1128/spectrum.00291-22Genomic Basis of Occurrence of Cryptic Resistance among Oxacillin- and Cefoxitin-Susceptible mecA-Positive Staphylococcus aureusBingshao Liang0Zhile Xiong1Zhuwei Liang2Chao Zhang3Hao Cai4Yan Long5Fei Gao6Jielin Wang7Qiulian Deng8Huamin Zhong9Yongqiang Xie10Lianfen Huang11Sitang Gong12Zhenwen Zhou13Clinical Laboratory, Guangzhou Women and Children’s Medical Center, Guangzhou Medical University, Guangzhou, People’s Republic of ChinaClinical Laboratory, Guangzhou Women and Children’s Medical Center, Guangzhou Medical University, Guangzhou, People’s Republic of ChinaClinical Laboratory, Guangzhou Women and Children’s Medical Center, Guangzhou Medical University, Guangzhou, People’s Republic of ChinaClinical Laboratory, Guangzhou Women and Children’s Medical Center, Guangzhou Medical University, Guangzhou, People’s Republic of ChinaClinical Laboratory, Guangzhou Women and Children’s Medical Center, Guangzhou Medical University, Guangzhou, People’s Republic of ChinaClinical Laboratory, Guangzhou Women and Children’s Medical Center, Guangzhou Medical University, Guangzhou, People’s Republic of ChinaClinical Laboratory, Guangzhou Women and Children’s Medical Center, Guangzhou Medical University, Guangzhou, People’s Republic of ChinaClinical Laboratory, Guangzhou Women and Children’s Medical Center, Guangzhou Medical University, Guangzhou, People’s Republic of ChinaClinical Laboratory, Guangzhou Women and Children’s Medical Center, Guangzhou Medical University, Guangzhou, People’s Republic of ChinaClinical Laboratory, Guangzhou Women and Children’s Medical Center, Guangzhou Medical University, Guangzhou, People’s Republic of ChinaClinical Laboratory, Guangzhou Women and Children’s Medical Center, Guangzhou Medical University, Guangzhou, People’s Republic of ChinaClinical Laboratory, Guangzhou Women and Children’s Medical Center, Guangzhou Medical University, Guangzhou, People’s Republic of ChinaDepartment of Gastroenterology, Guangzhou Women and Children’s Medical Center, Guangzhou Medical University, Guangzhou, People’s Republic of ChinaClinical Laboratory, Longgang District Maternity and Child Healthcare Hospital, Shenzhen, People’s Republic of ChinaABSTRACT The oxacillin– and cefoxitin-susceptible mecA–positive Staphylococcus aureus is a novel “stealth” methicillin-resistant S. aureus (MRSA) type. Here, we sequenced the whole genome of two oxacillin- and cefoxitin-susceptible mecA-positive MRSA isolates from breast abscesses in a lactating woman and a nasal swab of a healthy student in Guangzhou for investigating the mechanism underlying its occurrence. The reversion of these isolates was selected by exposure to sub-MICs of cefoxitin with or without mupirocin. The mecA expression of both parental strains and their revertants was determined, and the whole genome of the revertants was sequenced. Comparative whole-genome analyses performed for both strains revealed that mecA of the clinical strain was mutated by a single-bp insertion at the 262nd position in the tandem repeat region of the gene, and this mutation that led to the formation of a premature stop codon. The colonizing strain was mutated by a novel G-to-A base substitution in the second promoter region (–35 bp) of mecA. The mecA expression level of strain 697 revertant was 37 times higher than that of the parental strain. Although the mecA expression level was even higher for parental strain 199 compared with that for its revertant, its cDNA sequence contained a single-bp insertion. Collectively, both the missense and single substitution mutations of the second promoter of mecA could render MRSA isolates as “stealth” MRSA, thereby emphasizing the importance of combining phenotype tests with mecA or penicillin-binding protein 2a detection for the identification of MRSA. IMPORTANCE The oxacillin- and cefoxitin-susceptible mecA-positive Staphylococcus aureus is a novel type of “stealth” methicillin-resistant S. aureus (MRSA), which is difficult to be detected using conventional methods. To investigate the genomic basis of their occurrence, we sequenced the whole genome of two previously recovered oxacillin- and cefoxitin-susceptible mecA-positive MRSA isolates from breast abscesses in a lactating woman and a nasal swab of a healthy student in Guangzhou. Complete SCCmec structure was absent except for mecA in clinical isolate 199. Additionally, a novel single-base pair insertion was observed in the clinical strain, which resulted in premature termination and a frameshift mutation. The colonizing isolate 697 had a Scc-mec-type IVa, and the second promoter region (–35 bp) of mecA was mutated by a novel G-to-A base substitution. The reversion of oxacillin- and cefoxitin-susceptible mecA-positive S. aureus to resistant MRSA isolates was selected by exposure to subminimum inhibitory cefoxitin with or without mupirocin.https://journals.asm.org/doi/10.1128/spectrum.00291-22methicillin–resistant Staphylococcus aureusoxacillin– and cefoxitin–susceptible mecA–positive Staphylococcus aureusmecAblaZthird-generation sequencingquantitative polymerase chain reaction |
| spellingShingle | Bingshao Liang Zhile Xiong Zhuwei Liang Chao Zhang Hao Cai Yan Long Fei Gao Jielin Wang Qiulian Deng Huamin Zhong Yongqiang Xie Lianfen Huang Sitang Gong Zhenwen Zhou Genomic Basis of Occurrence of Cryptic Resistance among Oxacillin- and Cefoxitin-Susceptible mecA-Positive Staphylococcus aureus Microbiology Spectrum methicillin–resistant Staphylococcus aureus oxacillin– and cefoxitin–susceptible mecA–positive Staphylococcus aureus mecA blaZ third-generation sequencing quantitative polymerase chain reaction |
| title | Genomic Basis of Occurrence of Cryptic Resistance among Oxacillin- and Cefoxitin-Susceptible mecA-Positive Staphylococcus aureus |
| title_full | Genomic Basis of Occurrence of Cryptic Resistance among Oxacillin- and Cefoxitin-Susceptible mecA-Positive Staphylococcus aureus |
| title_fullStr | Genomic Basis of Occurrence of Cryptic Resistance among Oxacillin- and Cefoxitin-Susceptible mecA-Positive Staphylococcus aureus |
| title_full_unstemmed | Genomic Basis of Occurrence of Cryptic Resistance among Oxacillin- and Cefoxitin-Susceptible mecA-Positive Staphylococcus aureus |
| title_short | Genomic Basis of Occurrence of Cryptic Resistance among Oxacillin- and Cefoxitin-Susceptible mecA-Positive Staphylococcus aureus |
| title_sort | genomic basis of occurrence of cryptic resistance among oxacillin and cefoxitin susceptible meca positive staphylococcus aureus |
| topic | methicillin–resistant Staphylococcus aureus oxacillin– and cefoxitin–susceptible mecA–positive Staphylococcus aureus mecA blaZ third-generation sequencing quantitative polymerase chain reaction |
| url | https://journals.asm.org/doi/10.1128/spectrum.00291-22 |
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