Antibiotic Resistance and Serotypes Distribution in Streptococcus agalactiae Bulgarian Clinical Isolates During the Years of 2021–2024

Streptococcus agalactiae (group B Streptococcus, GBS) is an important human and animal pathogen. In recent years, the number of streptococcal isolates resistant to antimicrobial agents has increased in many parts of the world. Various mechanisms of antimicrobial resistance and capsular serotypes of...

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Main Authors: Boyanov Vasil S., Alexandrova Alexandra S., Hristova Preslava M., Hitkova Hristina Y., Gergova Raina T.
Format: Article
Language:English
Published: Sciendo 2024-12-01
Series:Polish Journal of Microbiology
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Online Access:https://doi.org/10.33073/pjm-2024-042
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author Boyanov Vasil S.
Alexandrova Alexandra S.
Hristova Preslava M.
Hitkova Hristina Y.
Gergova Raina T.
author_facet Boyanov Vasil S.
Alexandrova Alexandra S.
Hristova Preslava M.
Hitkova Hristina Y.
Gergova Raina T.
author_sort Boyanov Vasil S.
collection DOAJ
description Streptococcus agalactiae (group B Streptococcus, GBS) is an important human and animal pathogen. In recent years, the number of streptococcal isolates resistant to antimicrobial agents has increased in many parts of the world. Various mechanisms of antimicrobial resistance and capsular serotypes of GBS with different geographical distributions can be found. A prospective cross-sectional study was conducted from September 2021 to May 2024. The survey included 257 GBS isolates from Bulgarian inpatients and outpatients with streptococcal infections. Antibiotic resistance genes and capsular serotypes were detected and evaluated using polymerase chain reaction (PCR). We classified GBS isolates into groups according to their source as vaginal samples (191) and extra-vaginal samples (66), subdivided as invasive (36) and non-invasive specimens (30). The most common serotypes were Ia (26.5%), III (20.2%), and V (19.8%). Antimicrobial susceptibility testing revealed that all examined isolates were susceptible to penicillin and vancomycin. Resistance to macrolides, lincosamides, and tetracyclines was observed in 60.3%, 24.9%, and 89.1% of the isolates. The distribution of phenotypes was cMLSb 47.4%, iMLSb 30.8%, M-type 21.2%, and L-type 0.6%. PCR analysis revealed nine genes associated with macrolide and lincosamide resistance: ermB (54.2%), ermA/TR (30.3%), mefA (20.7%), ermC (18.1%), msrD (14.8%), mefE (8.4%), IsaC (8.4%), InuB (7.7%), and IsaE (6.5%). Two genes linked to tetracycline resistance tetM (89.1%) and tetO (14.4%) were detected. Compared to the previous period, we observed increased antibiotic resistance. There was no statistical significance between the distribution of serotypes and antimicrobial non-susceptibility depending on the sample source.
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spelling doaj-art-d14f8a4fba24453898d35c5ee7125bd02025-08-20T02:36:12ZengSciendoPolish Journal of Microbiology2544-46462024-12-0173450551410.33073/pjm-2024-042Antibiotic Resistance and Serotypes Distribution in Streptococcus agalactiae Bulgarian Clinical Isolates During the Years of 2021–2024Boyanov Vasil S.0Alexandrova Alexandra S.1Hristova Preslava M.2Hitkova Hristina Y.3Gergova Raina T.4Department of Medical Microbiology, Medical Faculty, Medical University of Sofia, Sofia, BulgariaDepartment of Medical Microbiology, Medical Faculty, Medical University of Sofia, Sofia, BulgariaDepartment of Microbiology and Virology, Medical University − Pleven, Pleven, BulgariaDepartment of Microbiology and Virology, Medical University − Pleven, Pleven, BulgariaDepartment of Medical Microbiology, Medical Faculty, Medical University of Sofia, Sofia, BulgariaStreptococcus agalactiae (group B Streptococcus, GBS) is an important human and animal pathogen. In recent years, the number of streptococcal isolates resistant to antimicrobial agents has increased in many parts of the world. Various mechanisms of antimicrobial resistance and capsular serotypes of GBS with different geographical distributions can be found. A prospective cross-sectional study was conducted from September 2021 to May 2024. The survey included 257 GBS isolates from Bulgarian inpatients and outpatients with streptococcal infections. Antibiotic resistance genes and capsular serotypes were detected and evaluated using polymerase chain reaction (PCR). We classified GBS isolates into groups according to their source as vaginal samples (191) and extra-vaginal samples (66), subdivided as invasive (36) and non-invasive specimens (30). The most common serotypes were Ia (26.5%), III (20.2%), and V (19.8%). Antimicrobial susceptibility testing revealed that all examined isolates were susceptible to penicillin and vancomycin. Resistance to macrolides, lincosamides, and tetracyclines was observed in 60.3%, 24.9%, and 89.1% of the isolates. The distribution of phenotypes was cMLSb 47.4%, iMLSb 30.8%, M-type 21.2%, and L-type 0.6%. PCR analysis revealed nine genes associated with macrolide and lincosamide resistance: ermB (54.2%), ermA/TR (30.3%), mefA (20.7%), ermC (18.1%), msrD (14.8%), mefE (8.4%), IsaC (8.4%), InuB (7.7%), and IsaE (6.5%). Two genes linked to tetracycline resistance tetM (89.1%) and tetO (14.4%) were detected. Compared to the previous period, we observed increased antibiotic resistance. There was no statistical significance between the distribution of serotypes and antimicrobial non-susceptibility depending on the sample source.https://doi.org/10.33073/pjm-2024-042streptococcus agalactiaegbsantimicrobial resistancecapsular serotypespcr
spellingShingle Boyanov Vasil S.
Alexandrova Alexandra S.
Hristova Preslava M.
Hitkova Hristina Y.
Gergova Raina T.
Antibiotic Resistance and Serotypes Distribution in Streptococcus agalactiae Bulgarian Clinical Isolates During the Years of 2021–2024
Polish Journal of Microbiology
streptococcus agalactiae
gbs
antimicrobial resistance
capsular serotypes
pcr
title Antibiotic Resistance and Serotypes Distribution in Streptococcus agalactiae Bulgarian Clinical Isolates During the Years of 2021–2024
title_full Antibiotic Resistance and Serotypes Distribution in Streptococcus agalactiae Bulgarian Clinical Isolates During the Years of 2021–2024
title_fullStr Antibiotic Resistance and Serotypes Distribution in Streptococcus agalactiae Bulgarian Clinical Isolates During the Years of 2021–2024
title_full_unstemmed Antibiotic Resistance and Serotypes Distribution in Streptococcus agalactiae Bulgarian Clinical Isolates During the Years of 2021–2024
title_short Antibiotic Resistance and Serotypes Distribution in Streptococcus agalactiae Bulgarian Clinical Isolates During the Years of 2021–2024
title_sort antibiotic resistance and serotypes distribution in streptococcus agalactiae bulgarian clinical isolates during the years of 2021 2024
topic streptococcus agalactiae
gbs
antimicrobial resistance
capsular serotypes
pcr
url https://doi.org/10.33073/pjm-2024-042
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AT hristovapreslavam antibioticresistanceandserotypesdistributioninstreptococcusagalactiaebulgarianclinicalisolatesduringtheyearsof20212024
AT hitkovahristinay antibioticresistanceandserotypesdistributioninstreptococcusagalactiaebulgarianclinicalisolatesduringtheyearsof20212024
AT gergovarainat antibioticresistanceandserotypesdistributioninstreptococcusagalactiaebulgarianclinicalisolatesduringtheyearsof20212024