Drug resistance and molecular epidemiology of OS-MRSA in Hulunbuir，Inner Mongolia

doi:10.3969/j.issn.1673-8640.2025.06.006

Abstract

Abstract:

Objective To analyze the drug resistance and molecular epidemiological characteristics of oxacillin-sensitive methicillin-resistant Staphylococcus aureus（OS-MRSA） in Hulunbuir，Inner Mongolia. Methods Staphylococcus aureus isolated clinically from 5 medical institutions in Hulunbuir from 2015 to 2021 were collected. Methicillin-resistant Staphylococcus aureus（MRSA） and methicillin-sensitive Staphylococcus aureus（MSSA） were screened based on the results of in vitro drug susceptibility test. The mecA and mecC of MSSA were determined by polymerase chain reaction（PCR），and the OS-MRSA isolates were screened out. Multilocus sequence typing（MLST） and Staphylococcus protein A typing（Spa） were performed. Results The determination rate of OS-MRSA in Hulunbuir was 1.20%. The sensitivities of OS-MRSA to tigecycline，moxifloxacin，linezolid，oxacillin，cefoxitin，rifampicin and vancomycin were 100.00%，the penicillin resistance rate was 100.00%，and OS-MRSA was resistant to erythromycin，sulfamethoxazole，gentamicin，clindamycin，tetracycline，ciprofloxacin and levofloxacin to varying degrees. Spa determined 10 types，and MLST determined 8 types. Conclusions No dominant type of OS-MRSA has been found in Hulunbuir，and it is sporadic overall. The conventional drug resistance phenotypic determination methods are prone to wrongly identify OS-MRSA as MSSA. The determination of mecA and mecC genes and drug resistance phenotypic determination should be combined to reduce the missed determination rate of OS-MRSA.

Key words: Oxacillin-sensitive methicillin-resistant Staphylococcus aureus, Methicillin-resistant Staphylococcus aureus, Drug resistance, Molecular typing

CLC Number:

R378.1

SUN Gang, SUN Hui, BAO Lina, LIU Xianwei, LU Mingyang, LIU Jing, TIAN Yuan. Drug resistance and molecular epidemiology of OS-MRSA in Hulunbuir，Inner Mongolia[J]. Laboratory Medicine, 2025, 40(6): 551-554.

Figures/Tables 3

References 14

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抗菌药物	敏感	中介	耐药
替加环素	13（100.00）	0（0.00）	0（0.00）
莫西沙星	13（100.00）	0（0.00）	0（0.00）
利奈唑胺	13（100.00）	0（0.00）	0（0.00）
苯唑西林	13（100.00）	0（0.00）	0（0.00）
万古霉素	13（100.00）	0（0.00）	0（0.00）
头孢西丁	13（100.00）	0（0.00）	0（0.00）
利福平	13（100.00）	0（0.00）	0（0.00）
环丙沙星	11（84.62）	1（7.69）	1（7.69）
四环素	11（84.62）	0（0.00）	2（15.38）
左氧氟沙星	11（84.62）	1（7.69）	1（7.69）
克林霉素	10（76.92）	0（0.00）	3（23.08）
庆大霉素	6（46.15）	2（15.38）	5（38.46）
复方磺胺甲噁唑	7（53.85）	0（0.00）	6（46.15）
红霉素	3（23.08）	0（0.00）	10（76.92）
青霉素	0（0.00）	0（0.00）	13（100.00）

抗菌药物	敏感	中介	耐药
替加环素	13（100.00）	0（0.00）	0（0.00）
莫西沙星	13（100.00）	0（0.00）	0（0.00）
利奈唑胺	13（100.00）	0（0.00）	0（0.00）
苯唑西林	13（100.00）	0（0.00）	0（0.00）
万古霉素	13（100.00）	0（0.00）	0（0.00）
头孢西丁	13（100.00）	0（0.00）	0（0.00）
利福平	13（100.00）	0（0.00）	0（0.00）
环丙沙星	11（84.62）	1（7.69）	1（7.69）
四环素	11（84.62）	0（0.00）	2（15.38）
左氧氟沙星	11（84.62）	1（7.69）	1（7.69）
克林霉素	10（76.92）	0（0.00）	3（23.08）
庆大霉素	6（46.15）	2（15.38）	5（38.46）
复方磺胺甲噁唑	7（53.85）	0（0.00）	6（46.15）
红霉素	3（23.08）	0（0.00）	10（76.92）
青霉素	0（0.00）	0（0.00）	13（100.00）

苯唑西林MIC值	菌株数/株	百分比/%
≤0.25 mg·L^-1	7	53.85
0.5 mg·L^-1	5	38.46
>0.5 mg·L^-1	1	7.69

苯唑西林MIC值	菌株数/株	百分比/%
≤0.25 mg·L^-1	7	53.85
0.5 mg·L^-1	5	38.46
>0.5 mg·L^-1	1	7.69

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