{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,13]],"date-time":"2026-05-13T15:58:59Z","timestamp":1778687939095,"version":"3.51.4"},"reference-count":15,"publisher":"SAGE Publications","issue":"6","license":[{"start":{"date-parts":[[2015,12,1]],"date-time":"2015-12-01T00:00:00Z","timestamp":1448928000000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/journals.sagepub.com\/page\/policies\/text-and-data-mining-license"}],"content-domain":{"domain":["journals.sagepub.com"],"crossmark-restriction":true},"short-container-title":["Microbial Drug Resistance"],"published-print":{"date-parts":[[2015,12]]},"abstract":"<jats:p>\n                    <jats:bold>\n                      <jats:italic toggle=\"yes\">Background:<\/jats:italic>\n                    <\/jats:bold>\n                    OmpK35 and OmpK36 are the major outer membrane porins of\n                    <jats:italic toggle=\"yes\">Klebsiella pneumoniae<\/jats:italic>\n                    . We aimed to study the effect of combined porin loss and production of extended-spectrum \u03b2-lactamases (ESBLs) on imipenem susceptibility among\n                    <jats:italic toggle=\"yes\">K. pneumoniae<\/jats:italic>\n                    clinical isolates.\n                    <jats:bold>\n                      <jats:italic toggle=\"yes\">Materials and Methods:<\/jats:italic>\n                    <\/jats:bold>\n                    This study included 91 suspected ESBL-producing\n                    <jats:italic toggle=\"yes\">K. pneumoniae<\/jats:italic>\n                    clinical isolates, isolated from different patient specimens at the Cairo University hospital from January to June 2010. All isolates were subjected to genotypic analysis of the outer membrane protein gene expression using reverse transcription-PCR (RT-PCR) and analysis of OmpK35\/36 of 38 isolates by sodium dodecyl sulfate\u2013polyacrylamide gel electrophoresis (SDS-PAGE).\n                    <jats:bold>\n                      <jats:italic toggle=\"yes\">Results:<\/jats:italic>\n                    <\/jats:bold>\n                    By RT-PCR, loss of Omp35 was detected in 78 (85.7%) isolates, loss of Omp36 was detected in 64 (70.32%), and loss of both porins was detected in 62 (68.1%). Out of 91 isolates, 45 (49.5%) were resistant to cefoxitin, and 17 (18.7%) were confirmed as derepressed AmpC producers. Omp35 was lost in all FOX-resistant isolates, whereas Omp36 was lost in 42 (93.3%) (\n                    <jats:italic toggle=\"yes\">p-<\/jats:italic>\n                    value 0.002). The mean of ceftazidime inhibition zone diameter was significantly decreased among ESBL-producing isolates with loss of Omp35\/36 (\n                    <jats:italic toggle=\"yes\">p<\/jats:italic>\n                    -value 0.041 and 0.006), respectively. The mean of imipenem minimal inhibitory concentration (MIC) was markedly increased to 8.55\u2009\u03bcg\/ml among AmpC-producing isolates with Omp35\/36 loss, while the mean of imipenem MIC among the 66 confirmed ESBL producers was 0.32\u2009\u03bcg\/ml.\n                    <jats:bold>\n                      <jats:italic toggle=\"yes\">Conclusion:<\/jats:italic>\n                    <\/jats:bold>\n                    Imipenem MIC was markedly increased among\n                    <jats:italic toggle=\"yes\">K. pneumoniae<\/jats:italic>\n                    isolates showing AmpC production with loss of both porins OmpK35\/36. Meanwhile, the association of porin OmpK35\/36 loss with ESBL production was not a direct cause of resistance to imipenem.\n                  <\/jats:p>","DOI":"10.1089\/mdr.2014.0226","type":"journal-article","created":{"date-parts":[[2015,5,6]],"date-time":"2015-05-06T15:23:52Z","timestamp":1430925832000},"page":"577-580","update-policy":"https:\/\/doi.org\/10.1177\/sage-journals-update-policy","source":"Crossref","is-referenced-by-count":30,"title":["The Role of OmpK35, OmpK36 Porins, and Production of \u03b2-Lactamases on Imipenem Susceptibility in\n                    <i>Klebsiella pneumoniae<\/i>\n                    Clinical Isolates, Cairo, Egypt"],"prefix":"10.1177","volume":"21","author":[{"given":"Mona","family":"Wassef","sequence":"first","affiliation":[{"name":"Cairo University","place":["Egypt"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Mona","family":"Abdelhaleim","sequence":"additional","affiliation":[{"name":"Cairo University","place":["Egypt"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Eiman","family":"AbdulRahman","sequence":"additional","affiliation":[{"name":"Cairo University","place":["Egypt"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Doaa","family":"Ghaith","sequence":"additional","affiliation":[{"name":"Cairo University","place":["Egypt"]}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"179","published-online":{"date-parts":[[2015,12]]},"reference":[{"key":"e_1_3_2_2_2","doi-asserted-by":"crossref","first-page":"177","DOI":"10.11604\/pamj.2014.19.177.4307","article-title":"Prevalence of extensively drug-resistant gram negative bacilli in surgical intensive care in Egypt","volume":"19","author":"Hasanin A.","year":"2014","unstructured":"Hasanin A., , Eladawy A., , Mohamed H., , Salah Y., , Lotfy A., , Mostafa H., , Ghaith D., , and Mukhtar A. 2014. Prevalence of extensively drug-resistant gram negative bacilli in surgical intensive care in Egypt. Pan Afr. Med. J., 19:177.","journal-title":"Pan Afr. Med. J."},{"key":"e_1_3_2_3_2","doi-asserted-by":"publisher","DOI":"10.4103\/0255-0857.13867"},{"key":"e_1_3_2_4_2","unstructured":"Clinical and Laboratory Standards Institute. 2010. Performance standards for antimicrobial susceptibility testing: 19th informational supplement. Document M100-S29. Clinical and Laboratory Standards Institute Wayne PA."},{"key":"e_1_3_2_5_2","doi-asserted-by":"crossref","first-page":"191","DOI":"10.1016\/j.ijid.2006.07.008","article-title":"Detection of plasmid-mediated Class C \u03b2-lactamases","volume":"11","author":"Doi Y.","year":"2007","unstructured":"Doi Y., , and Paterson D.L. 2007. Detection of plasmid-mediated Class C \u03b2-lactamases. Int. J. Infect. Dis., 11:191\u2013197.","journal-title":"Int. J. Infect. Dis."},{"key":"e_1_3_2_6_2","doi-asserted-by":"crossref","first-page":"3332","DOI":"10.1128\/AAC.47.10.3332-3335.2003","article-title":"Role of Klebsiella pneumoniae OmpK35 porin in antimicrobial resistance","volume":"47","author":"Dom\u00e9nech-S\u00e1nchez A.","year":"2003","unstructured":"Dom\u00e9nech-S\u00e1nchez A., , Mart\u00ednez-Mart\u00ednez L., , Hern\u00e1ndez-All\u00e9s S., , Conejo M.C., , \u00c1. Pascual, Tom\u00e1s J.M., , Albert\u00ed S., , and Bened\u00ed V.J. 2003. Role of Klebsiella pneumoniae OmpK35 porin in antimicrobial resistance. Antimicrob. Agents Chemother., 47:3332\u20133335.","journal-title":"Antimicrob. Agents Chemother."},{"key":"e_1_3_2_7_2","doi-asserted-by":"crossref","first-page":"639","DOI":"10.1016\/j.annemergmed.2008.11.007","article-title":"Invasive infection with hypermucoviscous Klebsiella pneumoniae: multiple cases presenting to a single emergency department in the United States","volume":"53","author":"Frazee B.W.","year":"2009","unstructured":"Frazee B.W., , Hansen S., , and Lambert L. 2009. Invasive infection with hypermucoviscous Klebsiella pneumoniae: multiple cases presenting to a single emergency department in the United States. Ann. Emerg. Med., 53:639\u2013642.","journal-title":"Ann. Emerg. Med."},{"key":"e_1_3_2_8_2","doi-asserted-by":"crossref","first-page":"4742","DOI":"10.1128\/AAC.00309-11","article-title":"OmpK26, a novel porin associated with carbapenem resistance in Klebsiella pneumoniae","volume":"55","author":"Garc\u00eda-Sureda L.","year":"2011","unstructured":"Garc\u00eda-Sureda L., , Dom\u00e9nech-S\u00e1nchez A., , Barbier M., , Juan C., , Gasc\u00f3 J., , and Albert\u00ed S. 2011. OmpK26, a novel porin associated with carbapenem resistance in Klebsiella pneumoniae. Antimicrob. Agents Chemother., 55:4742\u20134747.","journal-title":"Antimicrob. Agents Chemother."},{"key":"e_1_3_2_9_2","doi-asserted-by":"crossref","first-page":"1803","DOI":"10.1128\/AAC.01441-10","article-title":"Role of Klebsiella pneumoniae LamB porin in antimicrobial resistance","volume":"55","author":"Garc\u00eda-Sureda L.","year":"2011","unstructured":"Garc\u00eda-Sureda L., , Juan C., , Dom\u00e9nech-S\u00e1nchez A., , and Albert\u00ed S. 2011. Role of Klebsiella pneumoniae LamB porin in antimicrobial resistance. Antimicrob. Agents Chemother., 55:1803\u20131805.","journal-title":"Antimicrob. Agents Chemother."},{"key":"e_1_3_2_10_2","doi-asserted-by":"crossref","first-page":"673","DOI":"10.1099\/13500872-145-3-673","article-title":"Porin expression in clinical isolates of Klebsiella pneumoniae","volume":"145","author":"Hern\u00e1ndez-All\u00e9s S.","year":"1999","unstructured":"Hern\u00e1ndez-All\u00e9s S., , Albert\u00ed S., , Alvarez D., , Dom\u00e9nech-S\u00e1nchez A., , Mart\u00ednez-Mart\u00ednez L., , Gil J., , Tom\u00e1s J.M., , and Bened\u00ed V.J. 1999. Porin expression in clinical isolates of Klebsiella pneumoniae. Microbiology, 145: 673\u2013679.","journal-title":"Microbiology"},{"key":"e_1_3_2_11_2","doi-asserted-by":"crossref","first-page":"3203","DOI":"10.1128\/AAC.48.8.3203-3206.2004","article-title":"Role of \u03b2-lactamases and porins in resistance to ertapenem and other \u03b2-lactams in Klebsiella pneumoniae","volume":"48","author":"Jacoby G.A.","year":"2004","unstructured":"Jacoby G.A., , Mills D.M., , and Chow N. 2004. Role of \u03b2-lactamases and porins in resistance to ertapenem and other \u03b2-lactams in Klebsiella pneumoniae. Antimicrob. Agents Chemother., 48:3203\u20133206.","journal-title":"Antimicrob. Agents Chemother."},{"key":"e_1_3_2_12_2","doi-asserted-by":"crossref","first-page":"3396","DOI":"10.1128\/AAC.00285-06","article-title":"High-level carbapenem resistance in a Klebsiella pneumoniae clinical isolate is due to the combination of blaACT-1 \u03b2-lactamase production, porin OmpK35\/36 insertional inactivation, and down regulation of the phosphate transport porin PhoE","volume":"50","author":"Kaczmarek F.M.","year":"2006","unstructured":"Kaczmarek F.M., , Dib-Hajj F., , Shang W., , and Gootz T.D. 2006. High-level carbapenem resistance in a Klebsiella pneumoniae clinical isolate is due to the combination of blaACT-1 \u03b2-lactamase production, porin OmpK35\/36 insertional inactivation, and down regulation of the phosphate transport porin PhoE. Antimicrob. Agents Chemother., 50:3396\u20133406.","journal-title":"Antimicrob. Agents Chemother."},{"key":"e_1_3_2_13_2","first-page":"1","article-title":"Prevalence of OmpK35 and OmpK36 porin expression in beta-lactamase and non-beta lactamase-producing Klebsiella pneumoniae","volume":"6","author":"Shakib P.","year":"2012","unstructured":"Shakib P., , Ghafourian S., , Zolfaghary M.R., , Hushmandfar R., , Ranjbar R., , and Sadeghifard N. 2012. Prevalence of OmpK35 and OmpK36 porin expression in beta-lactamase and non-beta lactamase-producing Klebsiella pneumoniae. Biologics, 6:1\u20134.","journal-title":"Biologics"},{"key":"e_1_3_2_14_2","doi-asserted-by":"crossref","first-page":"125","DOI":"10.1179\/1973947813Y.0000000099","article-title":"The presence of blaKPC-mediated resistance in Enterobacteriaceae in Cairo University hospitals in Egypt and its correlation with in vitro carbapenem susceptibility","volume":"26","author":"Helal S.F.","year":"2014","unstructured":"Helal S.F., , El-Rachidi N. G., , AbdulRahman E.M., , and Hassan D.M. 2014. The presence of blaKPC-mediated resistance in Enterobacteriaceae in Cairo University hospitals in Egypt and its correlation with in vitro carbapenem susceptibility. J. Chemother., 26:125\u2013128.","journal-title":"J. Chemother."},{"key":"e_1_3_2_15_2","doi-asserted-by":"crossref","first-page":"1485","DOI":"10.1128\/AAC.01275-10","article-title":"Klebsiella pneumoniae outer membrane porins OmpK35 and OmpK36 play roles in both antimicrobial resistance and virulence","volume":"55","author":"Tsai Y.","year":"2011","unstructured":"Tsai Y., , Fung C., , Lin J., , Chen J., , Chang F., , Chen T., , and Siu L.K. 2011. Klebsiella pneumoniae outer membrane porins OmpK35 and OmpK36 play roles in both antimicrobial resistance and virulence. Antimicrob. Agents Chemother., 55:1485\u20131493.","journal-title":"Antimicrob. Agents Chemother."},{"key":"e_1_3_2_16_2","doi-asserted-by":"crossref","first-page":"366","DOI":"10.1007\/s00284-009-9364-4","article-title":"Combined porin loss and extended spectrum beta-lactamase production is associated with an increasing imipenem minimal inhibitory concentration in clinical Klebsiella pneumoniae strains","volume":"58","author":"Yang D.Y.","year":"2009","unstructured":"Yang D.Y., , Guo Y., , and Zhang Z. 2009. Combined porin loss and extended spectrum beta-lactamase production is associated with an increasing imipenem minimal inhibitory concentration in clinical Klebsiella pneumoniae strains. Curr. Microbiol., 58:366\u2013370.","journal-title":"Curr. Microbiol."}],"container-title":["Microbial Drug Resistance"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/journals.sagepub.com\/doi\/full-xml\/10.1089\/mdr.2014.0226","content-type":"application\/xml","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/journals.sagepub.com\/doi\/pdf\/10.1089\/mdr.2014.0226","content-type":"application\/pdf","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/journals.sagepub.com\/doi\/pdf\/10.1089\/mdr.2014.0226","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,5,1]],"date-time":"2026-05-01T20:29:04Z","timestamp":1777667344000},"score":1,"resource":{"primary":{"URL":"https:\/\/journals.sagepub.com\/doi\/full\/10.1089\/mdr.2014.0226"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2015,12]]},"references-count":15,"journal-issue":{"issue":"6","published-print":{"date-parts":[[2015,12]]}},"alternative-id":["10.1089\/mdr.2014.0226"],"URL":"https:\/\/doi.org\/10.1089\/mdr.2014.0226","relation":{},"ISSN":["1076-6294","1931-8448"],"issn-type":[{"value":"1076-6294","type":"print"},{"value":"1931-8448","type":"electronic"}],"subject":[],"published":{"date-parts":[[2015,12]]}}}