Association Between Rectal Colonization of Acinetobacter baumannii and Subsequent Invasive Infections in a Neonatal Intensive Care Unit

Abstract

Objective: Acinetobacter spp. is a significant nosocomial pathogen in neonatal intensive care units due to its environmental persistence and multidrug resistance profile. Rectal colonization in neonates may precede invasive infections such as bloodstream infection and ventilator-associated pneumonia, serving as a potential marker for subsequent clinical deterioration. However, the factors associated with progression from rectal colonization to systemic infection in this vulnerable population remain insufficiently defined.

Materials and Methods: This retrospective cohort study was conducted between January 2018 and January 2023. Neonates with rectal Acinetobacter spp. colonization detected by surveillance cultures were included. Patients were classified according to the development of culture-confirmed bloodstream infection (BSI) and/or ventilator-associated pneumonia (VAP) during follow-up. The primary outcome was the development of invasive Acinetobacter infection after rectal colonization, and its association with recurrent colonization episodes was evaluated.

Results: A total of 73 neonates with rectal Acinetobacter spp. colonization were included. During follow-up, 10 patients (13.7%) developed BSI and 5 (6.8%) developed VAP caused by Acinetobacter spp. Birth weight, gestational age, prematurity, central venous catheter use, and duration of respiratory support were comparable between groups (all p > 0.05). However, neonates who developed invasive infection had a significantly higher number of positive rectal surveillance cultures. The overall in-hospital mortality rate was 16.4%, with a higher but not statistically significant mortality observed in patients with invasive infection (30% vs. 14%, p = 0.14).

Conclusion: Among neonates with rectal Acinetobacter spp. colonization, recurrent positivity in surveillance cultures appears to be associated with an increased risk of subsequent invasive infection, suggesting that persistence of colonization may serve as a practical clinical marker to identify high-risk patients who require intensified monitoring and infection control measures.

Keywords

• Neonate
• Bloodstream infection
• Ventilator associated pneumonia
• Rectal swab
• Acinetobacter spp.

Rektal Acinetobacter baumannii Kolonizasyonu ile Yenidoğan Yoğun Bakım Ünitesinde İnvaziv Enfeksiyon Arasındaki İlişkinin Değerlendirilmesi

Abstract

Amaç: Acinetobacter spp., çevresel dirençliliği ve çoklu ilaç direnci profili nedeniyle yenidoğan yoğun bakım ünitelerinde önemli bir nozokomiyal patojendir. Yenidoğanlarda rektal kolonizasyon, kan dolaşımı enfeksiyonu ve ventilatör ilişkili pnömoni gibi invaziv enfeksiyonlardan önce görülebilir ve klinik kötüleşmenin potansiyel bir belirteci olabilir. Ancak bu hassas popülasyonda rektal kolonizasyondan sistemik enfeksiyona progresyonla ilişkili faktörler yeterince tanımlanmamıştır.
Gereç ve Yöntem: Bu retrospektif kohort çalışma Ocak 2018 – Ocak 2023 tarihleri arasında yürütüldü. Sürveyans kültürlerinde rektal Acinetobacter spp. kolonizasyonu saptanan yenidoğanlar çalışmaya dahil edildi. Hastalar takip sürecinde kültürle doğrulanmış kan dolaşımı enfeksiyonu (KDE) ve/veya ventilatör ilişkili pnömoni (VİP) gelişimine göre sınıflandırıldı. Birincil sonlanım noktası, rektal kolonizasyon sonrası invaziv Acinetobacter enfeksiyonu gelişimiydi ve bunun tekrarlayan kolonizasyon atakları ile ilişkisi değerlendirildi.
Bulgular: Rektal Acinetobacter spp. kolonizasyonu olan toplam 73 yenidoğan çalışmaya dahil edildi. İzlem süresince 10 hastada (%13,7) Acinetobacter kaynaklı KDE, 5 hastada (%6,8) ise VİP gelişti. Doğum ağırlığı, gebelik haftası, prematürite, santral venöz kateter kullanımı ve solunum desteği süresi açısından gruplar arasında anlamlı fark saptanmadı (tüm p > 0,05). Ancak invaziv enfeksiyon gelişen yenidoğanlarda pozitif rektal sürveyans kültürü sayısı anlamlı olarak daha yüksekti. Genel hastane içi mortalite oranı %16,4 olup, invaziv enfeksiyon gelişen hastalarda mortalite daha yüksek olmakla birlikte istatistiksel olarak anlamlı değildi (%30’a karşı %14, p = 0,14).

Sonuç: Rektal Acinetobacter spp. kolonizasyonu olan yenidoğanlarda sürveyans kültürlerinde tekrarlayan pozitiflik, sonraki invaziv enfeksiyon gelişme riski ile ilişkili görünmektedir. Kolonizasyonun persistan seyri, yoğun izlem ve enfeksiyon kontrol önlemlerinin artırılması gereken yüksek riskli hastaların belirlenmesinde pratik bir klinik belirteç olabilir.

Keywords

• Yenidoğan
• kan dolaşımı enfeksiyonu
• ventilatör ilişkili pnömoni
• rektal sürüntü
• Acinetobacter spp.

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