{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,25]],"date-time":"2026-02-25T12:11:38Z","timestamp":1772021498485,"version":"3.50.1"},"reference-count":30,"publisher":"MDPI AG","issue":"2","license":[{"start":{"date-parts":[[2026,2,20]],"date-time":"2026-02-20T00:00:00Z","timestamp":1771545600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Antibiotics"],"abstract":"<jats:p>Background\/Objectives: The rising prevalence of extended-spectrum beta-lactamase (ESBL)-producing pathogens has emerged as a significant challenge in the treatment of pyelonephritis. This study aims to determine the frequency of ESBL-producing agents in hospitalized patients with pyelonephritis, identify associated risk factors, and assess the appropriateness of empirical antimicrobial therapy. Methods: This prospective study included patients hospitalized with pyelonephritis in the Infectious Diseases Clinic of Ankara Training and Research Hospital between 1 October 2022 and 29 February 2024. Demographic features, comorbidities, urinary system pathologies, history of urinary tract interventions, hospitalization more than one month prior, antibiotic use within the previous three months, and prior urinary tract infections were compared between patients infected with ESBL-producing and non-ESBL-producing organisms. Antimicrobial susceptibility profiles and the appropriateness of empirical treatments were evaluated. Statistical analyses were performed using SPSS version 25.0, with p &lt; 0.05 considered statistically significant. Results: Escherichia coli (n = 142) and Klebsiella spp. (n = 43) were isolated in 180 of 204 patients. ESBL positivity was detected in 95 patients (52.7%). In the multivariate logistic regression analysis, male sex (p = 0.038) and hospitalization more than one month prior (p = 0.016) were identified as independent risk factors for ESBL positivity, while prior antibiotic use in the last three months showed a borderline association (p = 0.055) and did not reach statistical significance. ESBL production was not associated with prolonged hospitalization; however, bacteremia significantly increased length of stay (p &lt; 0.001). Antimicrobial susceptibility rates were markedly lower in the ESBL-positive group. The appropriateness of empirical therapy was also significantly reduced, with piperacillin\u2013tazobactam being the most frequently inappropriate agent due to high resistance rates and unnecessary broad-spectrum use. Conclusions: ESBL-producing pathogens were highly prevalent among hospitalized patients with pyelonephritis. The low appropriateness of empirical therapy in ESBL-positive cases underscores the need for careful evaluation of ESBL risk factors prior to treatment initiation, as ESBL rates may approach 50%.<\/jats:p>","DOI":"10.3390\/antibiotics15020229","type":"journal-article","created":{"date-parts":[[2026,2,23]],"date-time":"2026-02-23T10:00:52Z","timestamp":1771840852000},"page":"229","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Prospective Evaluation of ESBL Risk Factors and Appropriateness of Empirical Therapy in Hospitalized Patients with Community-Onset Pyelonephritis"],"prefix":"10.3390","volume":"15","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-7843-4165","authenticated-orcid":false,"given":"G\u00fcl\u015fah","family":"Geli\u015fig\u00fczel","sequence":"first","affiliation":[{"name":"Infectious Disese & Clinical Microbiology Clinic, Ankara Training and Research Hospital, Ankara 06230, T\u00fcrkiye"},{"name":"Infectious Disease & Clinical Microbiology Clinic, Ankara Etlik City Hospital, Ankara 06170, T\u00fcrkiye"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9295-4578","authenticated-orcid":false,"given":"\u015eerife","family":"Altun Demircan","sequence":"additional","affiliation":[{"name":"Infectious Disese & Clinical Microbiology Clinic, Ankara Training and Research Hospital, Ankara 06230, T\u00fcrkiye"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4068-5860","authenticated-orcid":false,"given":"Murat","family":"Aysin","sequence":"additional","affiliation":[{"name":"Department of Public Health, Bal\u0131kesir University Faculty of Medicine, Bal\u0131kesir 10145, T\u00fcrkiye"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3270-4841","authenticated-orcid":false,"given":"Esra","family":"Kaya K\u0131l\u0131\u00e7","sequence":"additional","affiliation":[{"name":"Infectious Disese & Clinical Microbiology Clinic, Ankara Training and Research Hospital, Ankara 06230, T\u00fcrkiye"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Serap","family":"Ya\u011fc\u0131","sequence":"additional","affiliation":[{"name":"Medical Microbiology Clinic, Ankara Training and Research Hospital, Ankara 06230, T\u00fcrkiye"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Sami","family":"K\u0131n\u0131kl\u0131","sequence":"additional","affiliation":[{"name":"Infectious Disese & Clinical Microbiology Clinic, Ankara Training and Research Hospital, Ankara 06230, T\u00fcrkiye"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Rukiye","family":"Berkem","sequence":"additional","affiliation":[{"name":"Medical Microbiology Clinic, Ankara Training and Research Hospital, Ankara 06230, T\u00fcrkiye"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2026,2,20]]},"reference":[{"key":"ref_1","first-page":"123","article-title":"Complicated urinary tract infections: Treatment and management","volume":"78","author":"Trautner","year":"2025","journal-title":"Clin. Infect. Dis."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"653","DOI":"10.1038\/nrurol.2010.190","article-title":"The epidemiology of urinary tract infection","volume":"7","author":"Foxman","year":"2010","journal-title":"Nat. Rev. Urol."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"48","DOI":"10.1056\/NEJMcp1702758","article-title":"Acute pyelonephritis in adults","volume":"378","author":"Johnson","year":"2018","journal-title":"N. Engl. J. Med."},{"key":"ref_4","unstructured":"Blaser, M.J., Cohen, J.I., and Holland, S.M. (2025). Urinary tract infections. Mandell, Douglas, and Bennett\u2019s Principles and Practice of Infectious Diseases, Elsevier. [10th ed.]."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"3945","DOI":"10.2147\/IDR.S269033","article-title":"Risk factors of extended-spectrum beta-lactamases-producing Escherichia coli community-acquired urinary tract infections: A systematic review","volume":"13","author":"Larramendy","year":"2020","journal-title":"Infect. Drug Resist."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"269","DOI":"10.1038\/nrmicro3432","article-title":"Urinary tract infections: Epidemiology, mechanisms of infection and treatment options","volume":"13","author":"Walker","year":"2015","journal-title":"Nat. Rev. Microbiol."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"780","DOI":"10.55730\/1300-0144.5641","article-title":"Multidrug resistance in pathogens of community-acquired urinary tract infections in Turkey: A multicentre prospective observational study","volume":"53","author":"Karabay","year":"2023","journal-title":"Turk. J. Med. Sci."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"678","DOI":"10.1016\/j.jsps.2018.02.023","article-title":"Risk factors for acquiring multidrug-resistant organisms in urinary tract infections: A systematic literature review","volume":"26","author":"Tenney","year":"2018","journal-title":"Saudi Pharm. J."},{"key":"ref_9","unstructured":"Belyayeva, M., Leslie, S.W., Rout, P., and Jeong, J.M. (2026, January 02). Acute Pyelonephritis. [Updated 2024 Feb 28], StatPearls [Internet], Available online: https:\/\/www.ncbi.nlm.nih.gov\/sites\/books\/NBK519537."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"581","DOI":"10.1007\/s10096-012-1795-3","article-title":"Antimicrobial agent exposure and the emergence and spread of resistant microorganisms: Issues associated with study design","volume":"32","author":"Angebault","year":"2013","journal-title":"Eur. J. Clin. Microbiol. Infect. Dis."},{"key":"ref_11","doi-asserted-by":"crossref","unstructured":"Y\u0131ld\u0131r\u0131m, \u00c7., Sar\u0131, S., Parmaks\u0131zo\u011flu Ayd\u0131n, A.M., Kilin\u00e7 Toker, A., Turun\u00e7 \u00d6zdemir, A., Erdem K\u0131vrak, E., Mermer, S., Kahraman, H., Soysal, O., and Y\u0131ld\u0131r\u0131m, H.\u00c7. (2025). Extended-Spectrum Beta-Lactamase Production and Carbapenem Resistance in Elderly Urinary Tract Infection Patients: A Multicenter Retrospective Study from Turkey. Antibiotics, 14.","DOI":"10.3390\/antibiotics14070719"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"e090665","DOI":"10.1136\/bmjopen-2024-090665","article-title":"Risk factors and drug resistance of adult community-onset urinary tract infections caused by Escherichia coli\u2013producing extended-spectrum \u03b2-lactamase in the Chongqing region, China: A retrospective case-control study","volume":"14","author":"Zhou","year":"2024","journal-title":"BMJ Open"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"e103","DOI":"10.1093\/cid\/ciq257","article-title":"International clinical practice guidelines for the treatment of acute uncomplicated cystitis and pyelonephritis in women: A 2010 update by the Infectious Diseases Society of America and the European Society for Microbiology and Infectious Diseases","volume":"52","author":"Gupta","year":"2011","journal-title":"Clin. Infect. Dis."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"ofad265","DOI":"10.1093\/ofid\/ofad265","article-title":"Epidemiology of Gram-negative bloodstream infections in the United States: Results from a cohort of 24 hospitals","volume":"10","author":"Ince","year":"2023","journal-title":"Open Forum Infect. Dis."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"148","DOI":"10.1016\/j.jgar.2021.05.016","article-title":"Impact of inappropriate empirical antibiotic treatment on clinical outcomes of urinary tract infections caused by Escherichia coli: A retrospective cohort study","volume":"26","author":"Zhu","year":"2021","journal-title":"J. Glob. Antimicrob. Resist."},{"key":"ref_16","doi-asserted-by":"crossref","unstructured":"Salam, M.A., Al-Amin, M.Y., Salam, M.T., Pawar, J.S., Akhter, N., Rabaan, A.A., and Alqumber, M.A.A. (2023). Antimicrobial resistance: A growing serious threat for global public health. Healthcare, 11.","DOI":"10.20944\/preprints202305.0555.v1"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"e51","DOI":"10.1093\/cid\/ciw118","article-title":"Implementing an antibiotic stewardship program: Guidelines by the Infectious Diseases Society of America and the Society for Healthcare Epidemiology of America","volume":"62","author":"Barlam","year":"2016","journal-title":"Clin. Infect. Dis."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"147","DOI":"10.1111\/j.1469-0691.2009.02941.x","article-title":"Risk factors for extended-spectrum beta-lactamase positivity in uropathogenic Escherichia coli isolated from community-acquired urinary tract infections","volume":"16","author":"Azap","year":"2010","journal-title":"Clin. Microbiol. Infect."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"421","DOI":"10.1007\/s10096-021-04392-2","article-title":"Inasing rates of extended-spectrum \u03b2-lactamase-producing Escherichia coli and Klebsiella pneumoniae in uncomplicated and complicated acute pyelonephritis and evaluation of empirical treatments based on culture results","volume":"41","author":"Kayaaslan","year":"2022","journal-title":"Eur. J. Clin. Microbiol. Infect. Dis."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"175","DOI":"10.1097\/00000441-200610000-00004","article-title":"The clinical impact of bacteremia in complicated acute pyelonephritis","volume":"332","author":"Hsu","year":"2006","journal-title":"Am. J. Med. Sci."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"e935478","DOI":"10.12659\/MSM.935478","article-title":"Retrospective study of the etiology, laboratory findings, and management of patients with urinary tract infections and urosepsis from a urology center in Silesia, southern Poland between 2017 and 2020","volume":"28","author":"Gofron","year":"2022","journal-title":"Med. Sci. Monit."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"79","DOI":"10.1016\/j.ijid.2015.03.006","article-title":"Urinary tract infections due to extended-spectrum beta-lactamase-producing Gram-negative bacteria: Identification of risk factors and outcome predictors in an Australian tertiary referral hospital","volume":"34","author":"Osthoff","year":"2015","journal-title":"Int. J. Infect. Dis."},{"key":"ref_23","unstructured":"World Health Organization (2025). WHO Regional Office for Europe Antimicrobial Medicines Consumption (AMC) Network: AMC Data 2023, World Health Organization Regional Office for Europe. Available online: https:\/\/iris.who.int\/handle\/10665\/380848."},{"key":"ref_24","doi-asserted-by":"crossref","unstructured":"Tamma, P.D., Aitken, S.L., Bonomo, R.A., Mathers, A.J., van Duin, D., and Clancy, C.J. (2023). Infectious Diseases Society of America 2023 Guidance on the Treatment of Antimicrobial-Resistant Gram-Negative Infections. Clin. Infect. Dis.","DOI":"10.1093\/cid\/ciad428"},{"key":"ref_25","doi-asserted-by":"crossref","unstructured":"Muteeb, G., Rehman, M.T., Shahwan, M., and Aatif, M. (2023). Origin of antibiotics and antibiotic resistance, and their impacts on drug development: A narrative review. Pharmaceuticals, 16.","DOI":"10.20944\/preprints202306.1921.v1"},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"985","DOI":"10.1016\/j.jiph.2020.03.004","article-title":"Impact of antibiotic de-escalation on hospitalized patients with urinary tract infections: A retrospective cohort single center study","volume":"13","author":"Alshareef","year":"2020","journal-title":"J. Infect. Public Health"},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"e2444495","DOI":"10.1001\/jamanetworkopen.2024.44495","article-title":"Guidelines for the prevention, diagnosis, and management of urinary tract infections in pediatrics and adults: A WikiGuidelines Group consensus statement","volume":"7","author":"Nelson","year":"2024","journal-title":"JAMA Netw. Open"},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"799","DOI":"10.1067\/j.cpradiol.2020.11.004","article-title":"Appropriateness of computed tomography and ultrasound for abdominal complaints in the emergency department","volume":"50","author":"Francisco","year":"2021","journal-title":"Curr. Probl. Diagn. Radiol."},{"key":"ref_29","unstructured":"European Committee on Antimicrobial Susceptibility Testing (EUCAST) (2022). Breakpoint Tables for Interpretation of MICs and Zone Diameters, EUCAST. Available online: https:\/\/www.eucast.org."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"46","DOI":"10.4111\/icu.2019.60.1.46","article-title":"Investigation of risk factors for community-a;quired urinary tract infections caused by extended-spectrum beta-lactamase Escherichia coli and Klebsiella species","volume":"60","author":"Koksal","year":"2019","journal-title":"Investig. Clin. Urol."}],"container-title":["Antibiotics"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2079-6382\/15\/2\/229\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,2,25]],"date-time":"2026-02-25T11:27:43Z","timestamp":1772018863000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2079-6382\/15\/2\/229"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,2,20]]},"references-count":30,"journal-issue":{"issue":"2","published-online":{"date-parts":[[2026,2]]}},"alternative-id":["antibiotics15020229"],"URL":"https:\/\/doi.org\/10.3390\/antibiotics15020229","relation":{},"ISSN":["2079-6382"],"issn-type":[{"value":"2079-6382","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,2,20]]}}}