{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,10]],"date-time":"2026-02-10T14:13:01Z","timestamp":1770732781863,"version":"3.49.0"},"reference-count":0,"publisher":"Journal of Infection in Developing Countries","issue":"01","license":[{"start":{"date-parts":[[2026,1,31]],"date-time":"2026-01-31T00:00:00Z","timestamp":1769817600000},"content-version":"unspecified","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["J Infect Dev Ctries"],"abstract":"<jats:p>Introduction: Ceftolozane-tazobactam (CLZ-TAZ) and ceftazidime-avibactam (CAZ-AVB) are recently developed \u03b2-lactam\/\u03b2-lactamase inhibitor combinations active against resistant Gram-negative bacteria. This study compared the in vitro activities of ceftazidime, meropenem, piperacillin-tazobactam (PIP-TAZ), CLZ-TAZ, and CAZ-AVB in Klebsiella pneumoniae isolates from Hacettepe University hospitals and investigated the carbapenemase types detected over the past five years.\nMethodology: A total of 550 K. pneumoniae isolates were collected consecutively from invasive clinical samples between 2015 and 2022 according to the SENTRY protocol. Identification was performed using matrix-assisted laser desorption ionization\u2013time of flight mass spectrometry (MALDI-TOF MS). Susceptibility testing for ceftazidime, meropenem, PIP-TAZ, CLZ-TAZ, and CAZ-AVB was carried out by broth microdilution and interpreted according to EUCAST standards. Carbapenemase genes were determined by whole-genome sequencing.\nResults: Isolates were obtained from blood (n = 191), skin\/soft tissue (n = 130), urine (n = 102), respiratory (n = 86), and intra-abdominal (n = 41) samples. Resistance rates were 62.3% for ceftazidime, 29.7% for meropenem, 60.4% for PIP-TAZ, 43.1% for CLZ-TAZ, and 8.7% for CAZ-AVB. The predominant carbapenemases were OXA-48, OXA-232, NDM-1, OXA-181, and KPC-2. Multiple carbapenemases coexisted in 10% of carbapenem-resistant isolates.\nConclusions: CAZ-AVB demonstrated superior activity compared to CLZ-TAZ in this high-resistance setting, While OXA-48 and NDM-1 remain the most frequent carbapenemases, emerging enzymes including OXA-181, OXA-232, KPC-3, and NDM-5 were also detected. The coexistence of multiple enzymes in single isolates highlights a growing therapeutic challenge, emphasizing the need for continued surveillance and effective antimicrobial stewardship.<\/jats:p>","DOI":"10.3855\/jidc.21385","type":"journal-article","created":{"date-parts":[[2026,2,9]],"date-time":"2026-02-09T18:07:44Z","timestamp":1770660464000},"page":"98-103","source":"Crossref","is-referenced-by-count":0,"title":["Ceftolozane-tazobactam and ceftazidime-avibactam efficacy against K. pneumoniae: first NDM-5 and OXA-232 report from T\u00fcrkiye"],"prefix":"10.3855","volume":"20","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-8352-9692","authenticated-orcid":false,"given":"Belgin","family":"Altun","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4546-9729","authenticated-orcid":false,"given":"G\u00fcl\u015fen","family":"Haz\u0131rolan","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Deniz","family":"G\u00fcr","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"2222","published-online":{"date-parts":[[2026,1,31]]},"container-title":["The Journal of Infection in Developing Countries"],"original-title":[],"link":[{"URL":"https:\/\/www.jidc.org\/index.php\/journal\/article\/download\/21385\/3810","content-type":"application\/pdf","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/www.jidc.org\/index.php\/journal\/article\/download\/21385\/3810","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,2,9]],"date-time":"2026-02-09T18:07:44Z","timestamp":1770660464000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.jidc.org\/index.php\/journal\/article\/view\/21385"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,1,31]]},"references-count":0,"journal-issue":{"issue":"01","published-online":{"date-parts":[[2026,1,31]]}},"URL":"https:\/\/doi.org\/10.3855\/jidc.21385","relation":{},"ISSN":["1972-2680"],"issn-type":[{"value":"1972-2680","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,1,31]]}}}