{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,4]],"date-time":"2026-05-04T19:22:01Z","timestamp":1777922521857,"version":"3.51.4"},"reference-count":0,"publisher":"SAGE Publications","issue":"3","license":[{"start":{"date-parts":[[2004,9,1]],"date-time":"2004-09-01T00:00:00Z","timestamp":1093996800000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/journals.sagepub.com\/page\/policies\/text-and-data-mining-license"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Microbial Drug Resistance"],"published-print":{"date-parts":[[2004,9]]},"abstract":"<jats:p>The prevalence of the internalization-associated prtF1 gene was studied in 837 isolates of Streptococcus pyogenes\nobtained from 713 pediatric patients presenting with acute pharyngotonsillitis before and after antibiotic\ntherapy. Its association with macrolide resistance and with bacteriological treatment failure was determined.\nThe bacterial population isolated from baseline pharyngeal swabs showed an overall prtF1 positivity\nrate of 33%. A higher prtF1 positivity was found among erythromycin-resistant strains (45%) showing, however,\nmarked differences between the inducible (iMLS), constitutive (cMLS), and efflux pump (M) resistance\nphenotypes. The prevalence was statistically higher (p &lt; 0.001) in strains belonging to iMLS (84%) and cMLS\n(67%) phenotypes as compared to the M phenotype (15%). Interestingly, the prevalence of the prtF1 gene\nwas significantly lower (p = 0.04) in strains belonging to M resistance phenotype as compared to erythromycinsusceptible\nstrains (28%). Failed bacterial eradication was demonstrated in 124 patients. The prtF1 positivity\nrate remained unchanged in strains isolated before and after therapy in patients treated with macrolides\n(9\/54). On the other hand, the positivity rate for the prtF1 gene was significantly higher (p = 0.015) in strains\nisolated after therapy with \u03b2-lactams (21\/70) as compared to baseline isolates (6\/70), indicating a differential\nselection imposed on the organism by these agents. Finally, a high overall eradication rate (88%) of prtF1-\npositive isolates, belonging to both the erythromycin-susceptible and -resistant phenotypes, was demonstrated\nfollowing macrolide treatment.<\/jats:p>","DOI":"10.1089\/mdr.2004.10.264","type":"journal-article","created":{"date-parts":[[2004,10,23]],"date-time":"2004-10-23T03:31:43Z","timestamp":1098502303000},"page":"264-268","source":"Crossref","is-referenced-by-count":6,"title":["Prevalence of the Internalization-Associated Gene prtF1 in aBacterial Population of Streptococcus pyogenes Isolated fromChildren with Acute Pharyngotonsillitis before and afterAntibiotic Therapy"],"prefix":"10.1177","volume":"10","author":[{"given":"C.E.","family":"Cocuzza","sequence":"first","affiliation":[{"name":"Department of Clinical Medicine, Prevention and Biotechnologies, University of Milano-Bicocca, Monza, Italy."}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"A.","family":"Lanzafame","sequence":"additional","affiliation":[{"name":"Institute of Microbiology, University of Milan, Milan, Italy."}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"F.","family":"Sisto","sequence":"additional","affiliation":[{"name":"Institute of Microbiology, University of Milan, Milan, Italy."}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"F.","family":"Broccolo","sequence":"additional","affiliation":[{"name":"Department of Clinical Medicine, Prevention and Biotechnologies, University of Milano-Bicocca, Monza, Italy."}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"R.","family":"Mattina","sequence":"additional","affiliation":[{"name":"Institute of Microbiology, University of Milan, Milan, Italy."}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"179","published-online":{"date-parts":[[2004,9]]},"container-title":["Microbial Drug Resistance"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/journals.sagepub.com\/doi\/pdf\/10.1089\/mdr.2004.10.264","content-type":"application\/pdf","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/journals.sagepub.com\/doi\/pdf\/10.1089\/mdr.2004.10.264","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,5,1]],"date-time":"2026-05-01T20:22:46Z","timestamp":1777666966000},"score":1,"resource":{"primary":{"URL":"https:\/\/journals.sagepub.com\/doi\/full\/10.1089\/mdr.2004.10.264"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2004,9]]},"references-count":0,"journal-issue":{"issue":"3","published-print":{"date-parts":[[2004,9]]}},"alternative-id":["10.1089\/mdr.2004.10.264"],"URL":"https:\/\/doi.org\/10.1089\/mdr.2004.10.264","relation":{},"ISSN":["1076-6294","1931-8448"],"issn-type":[{"value":"1076-6294","type":"print"},{"value":"1931-8448","type":"electronic"}],"subject":[],"published":{"date-parts":[[2004,9]]}}}