{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,22]],"date-time":"2026-09-22T13:33:42Z","timestamp":1790084022962,"version":"4.0.1"},"reference-count":29,"publisher":"MDPI AG","issue":"1","license":[{"start":{"date-parts":[[2023,1,12]],"date-time":"2023-01-12T00:00:00Z","timestamp":1673481600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"NSTDA RDI Research Grant","award":["P20-50-967"],"award-info":[{"award-number":["P20-50-967"]}]},{"name":"NSTDA RDI Research Grant","award":["B05F640141"],"award-info":[{"award-number":["B05F640141"]}]},{"name":"NSRF via Program Management Unit for Human Resources &amp; Institutional Development Research and Innovation","award":["P20-50-967"],"award-info":[{"award-number":["P20-50-967"]}]},{"name":"NSRF via Program Management Unit for Human Resources &amp; Institutional Development Research and Innovation","award":["B05F640141"],"award-info":[{"award-number":["B05F640141"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Antibiotics"],"abstract":"<jats:p>Streptococcus suis is a zoonotic pathogen causing disease in both animals and humans, and the emergence of increasingly resistant bacteria to antimicrobial agents has become a significant challenge globally. The objective of this study was to investigate the genetic basis for declining susceptibility to penicillin and other \u03b2-lactams among S. suis. Antimicrobial susceptibility testing and penicillin-binding proteins (PBP1a, PBP2a, PBP2b, and PBP2x) sequence analysis were performed on 225 S. suis isolated from diseased pigs. This study found that a growing trend of isolates displayed reduced susceptibility to \u03b2-lactams including penicillin, ampicillin, amoxicillin\/clavulanic acid, and cephalosporins. A total of 342 substitutions within the transpeptidase domain of four PBPs were identified, of which 18 substitutions were most statistically associated with reduced \u03b2-lactams susceptibility. Almost all the S. suis isolates which exhibited penicillin-non-susceptible phenotype (71.9%) had single nucleotide polymorphisms, leading to alterations of PBP1a (P409T) and PBP2a (T584A and H588Y). The isolates may manifest a higher level of penicillin resistance by additional mutation of M341I in the 339STMK active site motif of PBP2x. The ampicillin-non-susceptible isolates shared the mutations in PBP1a (P409T) and PBP2a (T584A and H588Y) with additional alterations of PBP2b (T625R) and PBP2x (T467S). The substitutions, including PBP1a (M587S\/T), PBP2a (M433T), PBP2b (I428L), and PBP2x (Q405E\/K\/L), appeared to play significant roles in mediating the reduction in amoxicillin\/clavulanic acid susceptibility. Among the cephalosporins, specific mutations strongly associated with the decrease in cephalosporins susceptibility were observed for ceftiofur: PBP1a (S477D\/G), PBP2a (E549Q and A568S), PBP2b (T625R), and PBP2x (Q453H). It is concluded that there was genetically widespread presence of PBPs substitutions associated with reduced susceptibility to \u03b2-lactam antibiotics.<\/jats:p>","DOI":"10.3390\/antibiotics12010158","type":"journal-article","created":{"date-parts":[[2023,1,12]],"date-time":"2023-01-12T03:47:01Z","timestamp":1673495221000},"page":"158","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":18,"title":["Relationship between Penicillin-Binding Proteins Alterations and \u03b2-Lactams Non-Susceptibility of Diseased Pig-Isolated Streptococcus suis"],"prefix":"10.3390","volume":"12","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-4080-763X","authenticated-orcid":false,"given":"Kamonwan","family":"Lunha","sequence":"first","affiliation":[{"name":"National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, Pathum Thani 12120, Thailand"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Wiyada","family":"Chumpol","sequence":"additional","affiliation":[{"name":"National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, Pathum Thani 12120, Thailand"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Surasak","family":"Jiemsup","sequence":"additional","affiliation":[{"name":"National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, Pathum Thani 12120, Thailand"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4823-858X","authenticated-orcid":false,"given":"Sukuma","family":"Samngamnim","sequence":"additional","affiliation":[{"name":"Department of Veterinary Medicine, Faculty of Veterinary Science, Chulalongkorn University, Bangkok 10330, Thailand"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Pornchalit","family":"Assavacheep","sequence":"additional","affiliation":[{"name":"Department of Veterinary Medicine, Faculty of Veterinary Science, Chulalongkorn University, Bangkok 10330, Thailand"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Suganya","family":"Yongkiettrakul","sequence":"additional","affiliation":[{"name":"National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, Pathum Thani 12120, Thailand"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2023,1,12]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Segura, M., Aragon, V., Brockmeier, S.L., Gebhart, C., Greeff, A., Kerdsin, A., O\u2019Dea, M.A., Okura, M., Sal\u00e9ry, M., and Schultsz, C. 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