Use of Recombinant Endolysin to Improve Accuracy of Group B Streptococcus Tests
ABSTRACT Group B Streptococcus (GBS) causes serious neonatal infection via vertical transmission. The prenatal GBS screening test is performed at the late stage of pregnancy to avoid risks of infection. In this test, enrichment culture is performed, followed by GBS identification. Selective medium i...
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| Format: | Article |
| Language: | English |
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American Society for Microbiology
2021-09-01
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| Series: | Microbiology Spectrum |
| Subjects: | |
| Online Access: | https://journals.asm.org/doi/10.1128/Spectrum.00077-21 |
| _version_ | 1818755151820750848 |
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| author | Hidehito Matsui Jumpei Uchiyama Masaya Ogata Tadahiro Nasukawa Iyo Takemura-Uchiyama Shin-ichiro Kato Hironobu Murakami Masato Higashide Hideaki Hanaki |
| author_facet | Hidehito Matsui Jumpei Uchiyama Masaya Ogata Tadahiro Nasukawa Iyo Takemura-Uchiyama Shin-ichiro Kato Hironobu Murakami Masato Higashide Hideaki Hanaki |
| author_sort | Hidehito Matsui |
| collection | DOAJ |
| description | ABSTRACT Group B Streptococcus (GBS) causes serious neonatal infection via vertical transmission. The prenatal GBS screening test is performed at the late stage of pregnancy to avoid risks of infection. In this test, enrichment culture is performed, followed by GBS identification. Selective medium is used for the enrichment; however, Enterococcus faecalis, which is a potential contaminant in swab samples, can interfere with the growth of GBS. Such bacterial contamination can lead to false-negative results. Endolysin, a bacteriophage-derived enzyme, degrades peptidoglycan in the bacterial cell wall; it is a promising antimicrobial agent for selectively eliminating specific bacterial genera/species. In this study, we used the recombinant endolysin EG-LYS, which is specific to E. faecalis; the endolysin potentially enriched GBS in the selective culture. First, in the false-negative model (coculture of GBS and E. faecalis, which disabled GBS detection in the subsequent GBS identification test), EG-LYS treatment at 0.1 mg/ml improved GBS detection. Next, we used 548 vaginal swabs to test the efficacy of EG-LYS treatment in improving GBS detection. EG-LYS treatment (0.1 mg/ml) increased the GBS-positive ratio to 17.9%, compared to 15.7% in the control (phosphate-buffered saline [PBS] treatment). In addition, there were an increased number of GBS colonies under EG-LYS treatment in some samples. The results were supported by the microbiota analysis of the enriched cultures. In conclusion, EG-LYS treatment of the enrichment culture potentially improves the accuracy of the prenatal GBS screening test. IMPORTANCE Endolysin is a bacteriophage-derived enzyme that degrades the peptidoglycan in the cell wall of host bacteria; it could be used as an antimicrobial agent for selectively eliminating specific bacterial genera/species. Group B Streptococcus (GBS) causes neonatal infection via vertical transmission; prenatal GBS screening test, in which enrichment culture is followed by bacterial identification, is used to detect the presence of GBS in pregnant women. However, the presence of commensal bacteria such as Enterococcus faecalis in clinical specimens can inhibit GBS growth in the selective enrichment culture, resulting in false-negative result. Here, we demonstrated that the application of originally isolated endolysin in the enrichment culture improved the test accuracy by inhibiting unwanted E. faecalis growth and therefore avoiding false-negative results, not only in experimental settings, but also in tests using vaginal swabs. |
| first_indexed | 2024-12-18T05:34:36Z |
| format | Article |
| id | doaj.art-a0080cbe2a0640b580e7f0219d177d32 |
| institution | Directory Open Access Journal |
| issn | 2165-0497 |
| language | English |
| last_indexed | 2024-12-18T05:34:36Z |
| publishDate | 2021-09-01 |
| publisher | American Society for Microbiology |
| record_format | Article |
| series | Microbiology Spectrum |
| spelling | doaj.art-a0080cbe2a0640b580e7f0219d177d322022-12-21T21:19:21ZengAmerican Society for MicrobiologyMicrobiology Spectrum2165-04972021-09-019110.1128/Spectrum.00077-21Use of Recombinant Endolysin to Improve Accuracy of Group B Streptococcus TestsHidehito Matsui0Jumpei Uchiyama1Masaya Ogata2Tadahiro Nasukawa3Iyo Takemura-Uchiyama4Shin-ichiro Kato5Hironobu Murakami6Masato Higashide7Hideaki Hanaki8Ōmura Satoshi Memorial Institute, Kitasato University, Tokyo, JapanDepartment of Bacteriology, Graduate School of Medicine Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, JapanSchool of Veterinary Medicine, Azabu University, Sagamihara, Kanagawa, JapanSchool of Veterinary Medicine, Azabu University, Sagamihara, Kanagawa, JapanSchool of Veterinary Medicine, Azabu University, Sagamihara, Kanagawa, JapanKochi University, Kochi, JapanSchool of Veterinary Medicine, Azabu University, Sagamihara, Kanagawa, JapanKotobiken Medical Laboratories, Inc., Tsukuba, Ibaraki, JapanŌmura Satoshi Memorial Institute, Kitasato University, Tokyo, JapanABSTRACT Group B Streptococcus (GBS) causes serious neonatal infection via vertical transmission. The prenatal GBS screening test is performed at the late stage of pregnancy to avoid risks of infection. In this test, enrichment culture is performed, followed by GBS identification. Selective medium is used for the enrichment; however, Enterococcus faecalis, which is a potential contaminant in swab samples, can interfere with the growth of GBS. Such bacterial contamination can lead to false-negative results. Endolysin, a bacteriophage-derived enzyme, degrades peptidoglycan in the bacterial cell wall; it is a promising antimicrobial agent for selectively eliminating specific bacterial genera/species. In this study, we used the recombinant endolysin EG-LYS, which is specific to E. faecalis; the endolysin potentially enriched GBS in the selective culture. First, in the false-negative model (coculture of GBS and E. faecalis, which disabled GBS detection in the subsequent GBS identification test), EG-LYS treatment at 0.1 mg/ml improved GBS detection. Next, we used 548 vaginal swabs to test the efficacy of EG-LYS treatment in improving GBS detection. EG-LYS treatment (0.1 mg/ml) increased the GBS-positive ratio to 17.9%, compared to 15.7% in the control (phosphate-buffered saline [PBS] treatment). In addition, there were an increased number of GBS colonies under EG-LYS treatment in some samples. The results were supported by the microbiota analysis of the enriched cultures. In conclusion, EG-LYS treatment of the enrichment culture potentially improves the accuracy of the prenatal GBS screening test. IMPORTANCE Endolysin is a bacteriophage-derived enzyme that degrades the peptidoglycan in the cell wall of host bacteria; it could be used as an antimicrobial agent for selectively eliminating specific bacterial genera/species. Group B Streptococcus (GBS) causes neonatal infection via vertical transmission; prenatal GBS screening test, in which enrichment culture is followed by bacterial identification, is used to detect the presence of GBS in pregnant women. However, the presence of commensal bacteria such as Enterococcus faecalis in clinical specimens can inhibit GBS growth in the selective enrichment culture, resulting in false-negative result. Here, we demonstrated that the application of originally isolated endolysin in the enrichment culture improved the test accuracy by inhibiting unwanted E. faecalis growth and therefore avoiding false-negative results, not only in experimental settings, but also in tests using vaginal swabs.https://journals.asm.org/doi/10.1128/Spectrum.00077-21endolysingroup B streptococcusEnterococcus faecalisStreptococcus agalactiaeGBS culture test |
| spellingShingle | Hidehito Matsui Jumpei Uchiyama Masaya Ogata Tadahiro Nasukawa Iyo Takemura-Uchiyama Shin-ichiro Kato Hironobu Murakami Masato Higashide Hideaki Hanaki Use of Recombinant Endolysin to Improve Accuracy of Group B Streptococcus Tests Microbiology Spectrum endolysin group B streptococcus Enterococcus faecalis Streptococcus agalactiae GBS culture test |
| title | Use of Recombinant Endolysin to Improve Accuracy of Group B Streptococcus Tests |
| title_full | Use of Recombinant Endolysin to Improve Accuracy of Group B Streptococcus Tests |
| title_fullStr | Use of Recombinant Endolysin to Improve Accuracy of Group B Streptococcus Tests |
| title_full_unstemmed | Use of Recombinant Endolysin to Improve Accuracy of Group B Streptococcus Tests |
| title_short | Use of Recombinant Endolysin to Improve Accuracy of Group B Streptococcus Tests |
| title_sort | use of recombinant endolysin to improve accuracy of group b streptococcus tests |
| topic | endolysin group B streptococcus Enterococcus faecalis Streptococcus agalactiae GBS culture test |
| url | https://journals.asm.org/doi/10.1128/Spectrum.00077-21 |
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