First Detection and Genomic Characterization of Linezolid-Resistant <i>Enterococcus faecalis</i> Clinical Isolates in Bulgaria
Linezolid is an oxazolidinone antibiotic and is considered a last-resort treatment option for serious infections caused by problematic Gram-positive pathogens, including vancomycin-resistant enterococci. The present study aimed to explore the linezolid resistance mechanisms and genomic characteristi...
Saved in:
| Main Authors: | , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2025-01-01
|
| Series: | Microorganisms |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2076-2607/13/1/195 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1832587858555174912 |
|---|---|
| author | Tanya V. Strateva Preslava Hristova Temenuga J. Stoeva Hristina Hitkova Slavil Peykov |
| author_facet | Tanya V. Strateva Preslava Hristova Temenuga J. Stoeva Hristina Hitkova Slavil Peykov |
| author_sort | Tanya V. Strateva |
| collection | DOAJ |
| description | Linezolid is an oxazolidinone antibiotic and is considered a last-resort treatment option for serious infections caused by problematic Gram-positive pathogens, including vancomycin-resistant enterococci. The present study aimed to explore the linezolid resistance mechanisms and genomic characteristics of two vancomycin-susceptible <i>Enterococcus faecalis</i> isolates from Bulgaria. The strains designated Efs2503-bg (inpatient from Pleven) and Efs966-bg (outpatient from Varna) were recovered from wounds in 2018 and 2023, respectively. Antimicrobial susceptibility testing, whole-genome sequencing, multilocus sequence typing, and phylogenomic analysis based on 332 linezolid-resistant <i>E. faecalis</i> genomes were performed. Efs2503-bg was high-level resistant to linezolid (MIC > 256 mg/L) and displayed the G2576T mutation affecting three of the four 23S rDNA loci. Efs966-bg (MIC = 8 mg/L) carried a plasmid-located <i>optrA</i> determinant surrounded by <i>fexA</i> and <i>ermA</i>. No mutations in the genes encoding for ribosomal proteins L3, L4, and L22 were detected. The isolates belonged to the sequence types ST6 (Efs2503-bg) and ST1102 (Efs966-bg). Phylogenomic analysis revealed that Efs2503-bg and Efs966-bg are genetically distinct, with a difference of 12,051 single-nucleotide polymorphisms. To our knowledge, this is the first report of linezolid-resistant enterococci in Bulgaria. Although the global incidence of linezolid-resistant enterococci is still low, their emergence is alarming and poses a growing clinical threat to public health. |
| format | Article |
| id | doaj-art-778cf023b2624745912bd7be771a6aac |
| institution | Kabale University |
| issn | 2076-2607 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Microorganisms |
| spelling | doaj-art-778cf023b2624745912bd7be771a6aac2025-01-24T13:43:00ZengMDPI AGMicroorganisms2076-26072025-01-0113119510.3390/microorganisms13010195First Detection and Genomic Characterization of Linezolid-Resistant <i>Enterococcus faecalis</i> Clinical Isolates in BulgariaTanya V. Strateva0Preslava Hristova1Temenuga J. Stoeva2Hristina Hitkova3Slavil Peykov4Department of Medical Microbiology “Corr. Mem. Prof. Ivan Mitov, MD, DMSc”, Faculty of Medicine, Medical University of Sofia, 2 Zdrave Str., 1431 Sofia, BulgariaDepartment of Microbiology and Virology, Faculty of Pharmacy, Medical University of Pleven, 1 St. Kliment Ohridski Str., 5800 Pleven, BulgariaDepartment of Microbiology and Virology, Faculty of Medicine, Medical University of Varna, 55 Marin Drinov Str., 9002 Varna, BulgariaDepartment of Microbiology and Virology, Faculty of Pharmacy, Medical University of Pleven, 1 St. Kliment Ohridski Str., 5800 Pleven, BulgariaDepartment of Medical Microbiology “Corr. Mem. Prof. Ivan Mitov, MD, DMSc”, Faculty of Medicine, Medical University of Sofia, 2 Zdrave Str., 1431 Sofia, BulgariaLinezolid is an oxazolidinone antibiotic and is considered a last-resort treatment option for serious infections caused by problematic Gram-positive pathogens, including vancomycin-resistant enterococci. The present study aimed to explore the linezolid resistance mechanisms and genomic characteristics of two vancomycin-susceptible <i>Enterococcus faecalis</i> isolates from Bulgaria. The strains designated Efs2503-bg (inpatient from Pleven) and Efs966-bg (outpatient from Varna) were recovered from wounds in 2018 and 2023, respectively. Antimicrobial susceptibility testing, whole-genome sequencing, multilocus sequence typing, and phylogenomic analysis based on 332 linezolid-resistant <i>E. faecalis</i> genomes were performed. Efs2503-bg was high-level resistant to linezolid (MIC > 256 mg/L) and displayed the G2576T mutation affecting three of the four 23S rDNA loci. Efs966-bg (MIC = 8 mg/L) carried a plasmid-located <i>optrA</i> determinant surrounded by <i>fexA</i> and <i>ermA</i>. No mutations in the genes encoding for ribosomal proteins L3, L4, and L22 were detected. The isolates belonged to the sequence types ST6 (Efs2503-bg) and ST1102 (Efs966-bg). Phylogenomic analysis revealed that Efs2503-bg and Efs966-bg are genetically distinct, with a difference of 12,051 single-nucleotide polymorphisms. To our knowledge, this is the first report of linezolid-resistant enterococci in Bulgaria. Although the global incidence of linezolid-resistant enterococci is still low, their emergence is alarming and poses a growing clinical threat to public health.https://www.mdpi.com/2076-2607/13/1/195<i>Enterococcus faecalis</i>linezolid resistancewhole-genome sequencingG2576T mutation<i>optrA</i>pAR0780 plasmid |
| spellingShingle | Tanya V. Strateva Preslava Hristova Temenuga J. Stoeva Hristina Hitkova Slavil Peykov First Detection and Genomic Characterization of Linezolid-Resistant <i>Enterococcus faecalis</i> Clinical Isolates in Bulgaria Microorganisms <i>Enterococcus faecalis</i> linezolid resistance whole-genome sequencing G2576T mutation <i>optrA</i> pAR0780 plasmid |
| title | First Detection and Genomic Characterization of Linezolid-Resistant <i>Enterococcus faecalis</i> Clinical Isolates in Bulgaria |
| title_full | First Detection and Genomic Characterization of Linezolid-Resistant <i>Enterococcus faecalis</i> Clinical Isolates in Bulgaria |
| title_fullStr | First Detection and Genomic Characterization of Linezolid-Resistant <i>Enterococcus faecalis</i> Clinical Isolates in Bulgaria |
| title_full_unstemmed | First Detection and Genomic Characterization of Linezolid-Resistant <i>Enterococcus faecalis</i> Clinical Isolates in Bulgaria |
| title_short | First Detection and Genomic Characterization of Linezolid-Resistant <i>Enterococcus faecalis</i> Clinical Isolates in Bulgaria |
| title_sort | first detection and genomic characterization of linezolid resistant i enterococcus faecalis i clinical isolates in bulgaria |
| topic | <i>Enterococcus faecalis</i> linezolid resistance whole-genome sequencing G2576T mutation <i>optrA</i> pAR0780 plasmid |
| url | https://www.mdpi.com/2076-2607/13/1/195 |
| work_keys_str_mv | AT tanyavstrateva firstdetectionandgenomiccharacterizationoflinezolidresistantienterococcusfaecalisiclinicalisolatesinbulgaria AT preslavahristova firstdetectionandgenomiccharacterizationoflinezolidresistantienterococcusfaecalisiclinicalisolatesinbulgaria AT temenugajstoeva firstdetectionandgenomiccharacterizationoflinezolidresistantienterococcusfaecalisiclinicalisolatesinbulgaria AT hristinahitkova firstdetectionandgenomiccharacterizationoflinezolidresistantienterococcusfaecalisiclinicalisolatesinbulgaria AT slavilpeykov firstdetectionandgenomiccharacterizationoflinezolidresistantienterococcusfaecalisiclinicalisolatesinbulgaria |