{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,5]],"date-time":"2026-10-05T04:11:14Z","timestamp":1791173474858,"version":"4.1.0"},"reference-count":30,"publisher":"American Society for Microbiology","issue":"8","license":[{"start":{"date-parts":[[2007,8,1]],"date-time":"2007-08-01T00:00:00Z","timestamp":1185926400000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/journals.asm.org\/non-commercial-tdm-license"}],"content-domain":{"domain":["journals.asm.org"],"crossmark-restriction":true},"short-container-title":["Antimicrob Agents Chemother"],"published-print":{"date-parts":[[2007,8]]},"abstract":"<jats:title>ABSTRACT<\/jats:title>\n                  <jats:p>\n                    A survey carried out in 2005 among members of a healthy population of children living in Bolivia and Peru revealed that fecal carriage of\n                    <jats:italic>Escherichia coli<\/jats:italic>\n                    strains resistant to expanded-spectrum cephalosporins was remarkably increased compared to that observed in the same settings in 2002 (1.7% in 2005 versus 0.1% in 2002). In this work, we demonstrated that this phenomenon was mainly related to the dissemination of CTX-M-type extended-spectrum \u03b2-lactamase (ESBL) determinants among commensal\n                    <jats:italic>E. coli<\/jats:italic>\n                    strains. Of 50 ESBL-producing isolates collected in the 2005 survey, 44 harbored a CTX-M-type and 6 an SHV-type (SHV-2 or SHV-12) ESBL. Compared to 2002 results, an increased diversity of CTX-M-type ESBLs was also observed: members of the CTX-M-1 group (CTX-M-15) emerged in Bolivia (where only CTX-M-2 was observed in 2002), while members of the CTX-M-9 group (CTX-M-14 and CTX-M-24) emerged in Peru (where only CTX-M-15 and CTX-M-2 were observed in 2002). A new CTX-M-2 variant named CTX-M-56 was also detected. Molecular characterization of the CTX-M-producing isolates and gene transfer experiments suggested that different mechanisms could be involved in the spreading of different CTX-M group determinants and revealed that additional resistance determinants for non-\u03b2-lactam antibiotics were preferentially carried by plasmids encoding certain CTX-M variants (CTX-M-15 and variants of the CTX-M-2 group). Three CTX-M-15-encoding conjugative plasmids from Peruvian isolates carried the new fluoroquinolone resistance gene\n                    <jats:italic>aac(6<\/jats:italic>\n                    \u2032\n                    <jats:italic>)-Ib-cr<\/jats:italic>\n                    . To our best knowledge, this is the first report of the detection of\n                    <jats:italic>aac(6<\/jats:italic>\n                    \u2032\n                    <jats:italic>)-Ib-cr<\/jats:italic>\n                    in Latin America.\n                  <\/jats:p>","DOI":"10.1128\/aac.00026-07","type":"journal-article","created":{"date-parts":[[2007,6,4]],"date-time":"2007-06-04T20:54:50Z","timestamp":1180990490000},"page":"2720-2725","update-policy":"https:\/\/doi.org\/10.1128\/asmj-crossmark-policy-page","source":"Crossref","is-referenced-by-count":115,"title":["Rapid Dissemination and Diversity of CTX-M Extended-Spectrum \u03b2-Lactamase Genes in Commensal\n                    <i>Escherichia coli<\/i>\n                    Isolates from Healthy Children from Low-Resource Settings in Latin America"],"prefix":"10.1128","volume":"51","author":[{"given":"Lucia","family":"Pallecchi","sequence":"first","affiliation":[{"name":"Dipartimento di Biologia Molecolare, Sezione di Microbiologia, Universita\u0300 di Siena, Siena, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Alessandro","family":"Bartoloni","sequence":"additional","affiliation":[{"name":"Dipartimento Area Critica Medico Chirurgica, Clinica Malattie Infettive, Universita\u0300 di Firenze, Florence, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Costanza","family":"Fiorelli","sequence":"additional","affiliation":[{"name":"Dipartimento Area Critica Medico Chirurgica, Clinica Malattie Infettive, Universita\u0300 di Firenze, Florence, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Antonia","family":"Mantella","sequence":"additional","affiliation":[{"name":"Dipartimento Area Critica Medico Chirurgica, Clinica Malattie Infettive, Universita\u0300 di Firenze, Florence, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Tiziana","family":"Di Maggio","sequence":"additional","affiliation":[{"name":"Dipartimento di Biologia Molecolare, Sezione di Microbiologia, Universita\u0300 di Siena, Siena, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Herlan","family":"Gamboa","sequence":"additional","affiliation":[{"name":"Distrito de Salud Cordillera, Departamento Santa Cruz, Camiri, Bolivia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Eduardo","family":"Gotuzzo","sequence":"additional","affiliation":[{"name":"Instituto de Medicina Tropical Alexander von Humboldt, Universidad Peruana Cayetano Heredia, Lima, Peru"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Go\u0308ran","family":"Kronvall","sequence":"additional","affiliation":[{"name":"Department of Microbiology and Tumor Biology-MTC, Clinical Microbiology, Karolinska Institut, Stockholm, Sweden"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Franco","family":"Paradisi","sequence":"additional","affiliation":[{"name":"Dipartimento Area Critica Medico Chirurgica, Clinica Malattie Infettive, Universita\u0300 di Firenze, Florence, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Gian Maria","family":"Rossolini","sequence":"additional","affiliation":[{"name":"Dipartimento di Biologia Molecolare, Sezione di Microbiologia, Universita\u0300 di Siena, Siena, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"235","reference":[{"key":"e_1_3_2_2_2","doi-asserted-by":"publisher","DOI":"10.3201\/eid1206.051258"},{"key":"e_1_3_2_3_2","doi-asserted-by":"publisher","DOI":"10.1128\/AAC.40.2.509"},{"key":"e_1_3_2_4_2","doi-asserted-by":"publisher","DOI":"10.1086\/500936"},{"key":"e_1_3_2_5_2","doi-asserted-by":"publisher","DOI":"10.1002\/j.1460-2075.1992.tb05333.x"},{"key":"e_1_3_2_6_2","doi-asserted-by":"publisher","DOI":"10.1128\/AAC.48.1.1-14.2004"},{"key":"e_1_3_2_7_2","doi-asserted-by":"publisher","DOI":"10.1128\/AAC.48.10.3758-3764.2004"},{"key":"e_1_3_2_8_2","doi-asserted-by":"publisher","DOI":"10.1128\/CMR.14.4.933-951.2001"},{"key":"e_1_3_2_9_2","doi-asserted-by":"publisher","DOI":"10.1128\/AAC.47.6.2056-2058.2003"},{"key":"e_1_3_2_10_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.mib.2006.08.011"},{"key":"e_1_3_2_11_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.mimet.2005.03.018"},{"key":"e_1_3_2_12_2","doi-asserted-by":"publisher","DOI":"10.1128\/AEM.66.10.4555-4558.2000"},{"key":"e_1_3_2_13_2","unstructured":"Performance standards for antimicrobial disk susceptibility tests; 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