{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,29]],"date-time":"2026-07-29T14:59:58Z","timestamp":1785337198541,"version":"3.55.0"},"reference-count":36,"publisher":"MDPI AG","issue":"15","license":[{"start":{"date-parts":[[2026,7,29]],"date-time":"2026-07-29T00:00:00Z","timestamp":1785283200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["J. Clin. Med.","JCM"],"abstract":"<jats:p>Objective: The purpose of this study was to evaluate the factors, particularly post-vaccination C-reactive protein (CRP) and the neutrophil-to-lymphocyte ratio (NLR), associated with the clinical decision to initiate antibiotic treatment following the 2-month diphtheria\u2013acellular pertussis\u2013tetanus\u2013Haemophilus influenzae Type B\u2013inactivated poliovirus (DaBT-Hib-IPV) vaccine in hospitalized infants. Methods: A retrospective review was conducted on the medical records of 46 infants. The study included infants hospitalized between 2022 and 2024 at Mersin City Training and Research Hospital who received the 2-month vaccine and subsequently underwent post-vaccination laboratory testing. Infants were categorized based on whether they received antibiotic treatment. Results: Antibiotics were administered to 20 infants, and 26 were observed without any treatment. Despite having a significantly higher gestational age (p = 0.027), the hospital stays of the antibiotic group were significantly longer (median 99 vs. 78 days, p &lt; 0.001). C-reactive protein (CRP) and the neutrophil-to-lymphocyte ratio (NLR) were elevated in the antibiotic group (CRP = 2.82 vs. 1.63 mg\/dL, p &lt; 0.001; NLR= 0.90 vs. 0.72, p = 0.041). Culture positivity was low in antibiotic recipients (3\/20, 15%). CRP was the only independent predictor of antibiotic administration when adjusted for gestational age and weight at vaccination (Exp(B) = 3.997, p = 0.003). Conclusions: In this cohort of NICU-hospitalized, predominantly preterm infants, a population that does not represent the general population of vaccinated 2-month-old infants, post-vaccination elevations in CRP and NLRs were associated with the clinical decision to initiate antibiotic treatment; however, in the absence of a validated infection reference standard, these markers cannot be assumed to reliably differentiate true infection from vaccine-induced inflammation. To prevent unnecessary antibiotic use and optimize patient management, these markers must be evaluated in conjunction with clinical findings, culture results, and supplementary biomarkers.<\/jats:p>","DOI":"10.3390\/jcm15155934","type":"journal-article","created":{"date-parts":[[2026,7,29]],"date-time":"2026-07-29T13:53:31Z","timestamp":1785333211000},"page":"5934","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Factors Associated with Antibiotic Initiation After DaBT-Hib-IPV Vaccination in NICU-Hospitalized Preterm Infants: The Role of C-Reactive Protein"],"prefix":"10.3390","volume":"15","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-3453-6802","authenticated-orcid":false,"given":"H\u00fcseyin","family":"\u015eim\u015fek","sequence":"first","affiliation":[{"name":"Neonatology Department, Mersin City Training and Research Hospital, 33240 Mersin, T\u00fcrkiye"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mustafa","family":"Ak\u00e7al\u0131","sequence":"additional","affiliation":[{"name":"Neonatology Department, Mersin City Training and Research Hospital, 33240 Mersin, T\u00fcrkiye"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4041-2777","authenticated-orcid":false,"given":"Mehtap","family":"Durukan Tosun","sequence":"additional","affiliation":[{"name":"Neonatology Department, Mersin City Training and Research Hospital, 33240 Mersin, T\u00fcrkiye"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5054-8507","authenticated-orcid":false,"given":"Berfin","family":"\u00d6zmen","sequence":"additional","affiliation":[{"name":"Department of Pediatric Infectious Diseases, Mersin City Training and Research Hospital, 33240 Mersin, T\u00fcrkiye"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Suna","family":"\u00d6zdem","sequence":"additional","affiliation":[{"name":"Department of Pediatric Infectious Diseases, Mersin City Training and Research Hospital, 33240 Mersin, T\u00fcrkiye"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,7,29]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"e2021052456","DOI":"10.1542\/peds.2021-052456","article-title":"Early-Onset Sepsis Among Very Preterm Infants","volume":"148","author":"Flannery","year":"2021","journal-title":"Pediatrics"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"F9","DOI":"10.1136\/adc.2009.178798","article-title":"Neonatal infections in England: The NeonIN surveillance network","volume":"96","author":"Vergnano","year":"2011","journal-title":"Arch. 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