{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,7]],"date-time":"2026-04-07T16:58:08Z","timestamp":1775581088101,"version":"3.50.1"},"reference-count":56,"publisher":"Index Copernicus","issue":"6","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Pol Przegl Chir"],"published-print":{"date-parts":[[2025,11,21]]},"abstract":"<ns3:p>&lt;b&gt;Introduction:&lt;\/b&gt; Anaerobic bloodstream infections caused by Gram-negative bacilli are rare, but the mortality rate remains high. Increasing resistance complicates treatment strategies.&lt;b&gt;Aim:&lt;\/b&gt; This study aimed to assess the clinical and microbiological characteristics of BSIs caused by &lt;i&gt;Bacteroides&lt;\/i&gt; spp. and related genera, and to evaluate the antibiotic susceptibility of isolated strains in adult patients hospitalized in a multidisciplinary Polish hospital over a 10-year period.&lt;b&gt;Materials and methods:&lt;\/b&gt; A retrospective, observational, single-center study included adult patients diagnosed with anaerobic BSIs between 2014 and 2023. Microbiological identification was performed using MALDI-TOF MS. Antimicrobial susceptibility was evaluated &lt;i&gt;via&lt;\/i&gt; gradient diffusion assay and interpreted according to EUCAST.&lt;b&gt;Results:&lt;\/b&gt; Anaerobic BSIs caused by &lt;i&gt;Bacteroides&lt;\/i&gt; spp. and &lt;i&gt;Phocaeicola &lt;\/i&gt;spp. were identified in 24 patients (mean age: 65.6 years). &lt;i&gt;B. fragilis &lt;\/i&gt;was the most common isolate (62.5%). Mortality among these hospitalized patients was 46%, with a significantly higher risk observed in elderly patients (median age of deceased: 83 years). All isolates were susceptible to metronidazole and carbapenems; 25% showed resistance to clindamycin.&lt;b&gt;Discussion:&lt;\/b&gt; The study confirmed high mortality, significant age-related risk, and variable antimicrobial susceptibility. Notably, &lt;i&gt;Bacteroides&lt;\/i&gt;-related BSIs often originated from gastrointestinal and urinary sources and were associated with chronic comorbidities, including renal failure.&lt;b&gt;Conclusions:&lt;\/b&gt; Empirical treatment regimens must consider increasing resistance among anaerobes. Timely microbiological diagnostics, including anaerobic cultures and susceptibility testing, are essential to guide therapy and improve patient outcomes.&lt;b&gt;Significance:&lt;\/b&gt; This study underscores the necessity for ongoing surveillance of anaerobic BSIs and highlights gaps in empirical treatment practices, advocating for broader clinical awareness and targeted antimicrobial stewardship.<\/ns3:p>","DOI":"10.5604\/01.3001.0055.4473","type":"journal-article","created":{"date-parts":[[2025,12,30]],"date-time":"2025-12-30T10:56:24Z","timestamp":1767092184000},"page":"48-56","source":"Crossref","is-referenced-by-count":1,"title":["Bloodstream infections caused by Bacteroides and Phocaeicola: clinical relevance and antimicrobial susceptibility. Presentation of twenty-four cases."],"prefix":"10.5604","volume":"97","author":[{"given":"Marta","family":"Kierzkowska","sequence":"first","affiliation":[{"name":"1.\tLaboratory of Microbiology, University Center of Laboratory Medicine, Medical University of Warsaw, 1a Banacha Str., Warsaw 02-097, Poland\n2.\tHuman Biome Institute, 1 Starodworska Str., Gdansk 80-137, Poland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Dariusz","family":"Kawecki","sequence":"additional","affiliation":[{"name":"Department of Medical Microbiology, Chalubinski 5 Str. Medical University of Warsaw, Poland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Edyta","family":"Podsiad\u0142y","sequence":"additional","affiliation":[{"name":"1.\tLaboratory of Microbiology, University Center of Laboratory Medicine, Medical University of Warsaw, 1a Banacha Str., Warsaw 02-097, Poland\n2.\tDepartment of Dental Microbiology, Medical University of Warsaw,1a Banacha Str., Warsaw 02-097, Poland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9036-7452","authenticated-orcid":false,"given":"Anna","family":"Majewska","sequence":"additional","affiliation":[{"name":"Department of Medical Microbiology, Chalubinski 5 Str. Medical University of Warsaw, Poland"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"3689","reference":[{"key":"633856r1","doi-asserted-by":"crossref","unstructured":"Niederman M.S., Baron R.M., Bouadma L. et al.: Initial antimicrobial management of sepsis. 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