{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,5,14]],"date-time":"2025-05-14T12:07:17Z","timestamp":1747224437046,"version":"3.40.5"},"reference-count":0,"publisher":"Sri Lanka Journals Online","issue":"SI3","license":[{"start":{"date-parts":[[2024,9,19]],"date-time":"2024-09-19T00:00:00Z","timestamp":1726704000000},"content-version":"unspecified","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Ceylon Med. J."],"abstract":"<jats:p>Introduction: Varying combinations of \u03b2-lactamase genes (bla) in Enterobacterales manifest different resistant phenotypes.Objectives: This study aimed to identify bla gene types and combinations resulting in variations in phenotypic antimicrobial resistance.Methods: Minimum inhibitory concentrations (MICs) of 75 extended spectrum \u03b2-lactamase (ESBL), AmpC \u03b2-lactamase and carbapenemase-producing Entero-bacterales isolates from a variety of clinical specimens were determined by Vitek micro-broth dilution. Bla genes were detected by 16-plex tandem PCR panel and Xpert Carba-R assay. BlaCTX-M group-1 and blaOXA-48 were the most common ESBL and carbapenemase genes, respectively.Results: Majority of the isolates (92%, 69\/75) had bla gene combinations. Thirty-eight isolates (51%) carried ESBL, AmpC genes and\/or narrow spectrum bla genes without any carbapenemase genes. The common bla gene combination in these isolates was blaCTX-M group-1 + blaOXA1 which is known to confer decreased susce-ptibility to piperacillin-tazobactam. Antibiotics with potential activity against ESBL-producing bacteria such as fourth generation cephalosporins, \u03b2-lactam\/\u03b2-lactam-inhibitor combinations, quinolones and gentamicin also showed low rates of susceptibility. Highest susceptibility rates were to meropenem (92%) and amikacin (92%). Thirty-seven isolates (49%) carried carbapenemase genes as well. These isolates showed even higher resistance rates to all antibiotics, except amikacin (92%susceptible). Significantly higher MIC values for cefoxitin, ceftazidime, ceftriaxone, cefepime, meropenem, amikacin, tobramycin and trimethoprim-sulfamethoxazole were seen in isolates carrying blaNDM than blaOXA-48. However, a higher MIC for norfloxacin was seen in isolates with blaOXA-48.Conclusions: In conclusion, this study showed that Enterobacterales with different bla gene combinations manifest variations in phenotypic resistance to both \u03b2-lactam and non-\u03b2-lactam antibiotics.<\/jats:p>","DOI":"10.4038\/cmj.v69isi3.9953","type":"journal-article","created":{"date-parts":[[2024,9,19]],"date-time":"2024-09-19T05:38:32Z","timestamp":1726724312000},"page":"23-36","source":"Crossref","is-referenced-by-count":0,"title":["Phenotypic antimicrobial resistance associated with different &lt;em&gt;bla&lt;\/em&gt; genotypes and their combinations in Enterobacterales"],"prefix":"10.4038","volume":"69","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-8905-9882","authenticated-orcid":false,"given":"Vindya","family":"Perera","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6482-9649","authenticated-orcid":false,"given":"Harsha","family":"Samarasekara","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Upamali","family":"Herath","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Jayanthi","family":"Elvitigala","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7437-6375","authenticated-orcid":false,"given":"Shirani","family":"Chandrasiri","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1450-2098","authenticated-orcid":false,"given":"Enoka","family":"Corea","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"2473","published-online":{"date-parts":[[2024,9,19]]},"container-title":["Ceylon Medical Journal"],"original-title":[],"link":[{"URL":"https:\/\/account.cmj.sljol.info\/index.php\/sljo-j-cmj\/article\/download\/9953\/6897","content-type":"application\/pdf","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/account.cmj.sljol.info\/index.php\/sljo-j-cmj\/article\/download\/9953\/6897","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2024,9,19]],"date-time":"2024-09-19T05:38:40Z","timestamp":1726724320000},"score":1,"resource":{"primary":{"URL":"https:\/\/account.cmj.sljol.info\/index.php\/sljo-j-cmj\/article\/view\/9953"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2024,9,19]]},"references-count":0,"journal-issue":{"issue":"SI3","published-online":{"date-parts":[[2024,9,19]]}},"URL":"https:\/\/doi.org\/10.4038\/cmj.v69isi3.9953","relation":{},"ISSN":["2386-1274","0009-0875"],"issn-type":[{"type":"electronic","value":"2386-1274"},{"type":"print","value":"0009-0875"}],"subject":[],"published":{"date-parts":[[2024,9,19]]}}}