Prevalence and Antibiotic Resistance Rates of Gram-Negative Bacteria Isolated in Blood Cultures Sent from Intensive Care Units in Baku: A Multicenter Study

Abstract

The increase in morbidity and mortality rates in intensive care units (ICUs) is frequently associated with hospital-acquired infections, representing one of the most serious threats to healthcare systems worldwide. This study aims to identify Gram-negative bacteria isolated from blood culture samples obtained from ICU patients and to evaluate their antibiotic susceptibility profiles. This study included bacteria detected in blood samples collected from patients hospitalized in the neonatal, pediatric, and adult intensive care units of three major hospitals located in Baku (Azerbaijan). Blood culture bottles submitted to our laboratory were initially placed into the BACT/ALERT 3D 60 (BIOMERIEUX, France) automated culture system. Bottles produced a positive signal were inoculated on appropriate media, and microorganisms were isolated from the cultures that showed growth. Bacterial identification was performed using VITEK 2 Compact system (BioMérieux, France). Antimicrobial susceptibility was determined using the VITEK 2 Compact system (bioMérieux, France), and the results were interpreted in accordance with the European Committee on Antimicrobial Susceptibility Testing (EUCAST) guidelines. A total of 1226 (54.5%) microorganisms were isolated from 2250 blood samples. Among the 1226 microbial growth, 759 (61.9%) were identified as Gram-positive bacteria, 385 (31.4%) as Gram-negative bacteria, and 82 (6.7%) as yeasts. The most frequently isolated Gram-negative bacteria were Serratia marcescens (n=76, 19.7%), Klebsiella pneumoniae (n=68, 17.7%) ve Acinetobacter spp. (n=47, 12.2%) respectively. High resistance rates were observed among the isolated strains, particularly in Acinetobacter baumannii (ciprofloxacin 80.9%), K. pneumoniae (ciprofloxacin 82.4%), Enterobacter spp. (cefotaxime 75.7%), Serratia spp. (imipenem 75.0%) and S. marcescens (cefotaxime and ciprofloxacin 64.5%). Our findings indicate markedly elevated resistance rates among Gram-negative isolates recovered from intensive hospital settings. Resistance to ciprofloxacin was documented in 82.7% of Acinetobacter spp. and 82.4% of Klebsiella pneumoniae isolates. Notably, carbapenem resistance reached 75.0% in Serratia spp., while 75.7% of Enterobacter spp. isolates exhibited resistance to cefotaxime. These resistance levels reflect substantial antimicrobial selection pressure within critical care units. The data highlight the urgent need for strengthened antimicrobial stewardship programs and robust infection prevention strategies in Azerbaijan, particularly in Baku.

Keywords

• Antimicrobial susceptibility
• Multidrug resistance (MDR)
• Carbapenem resistance
• Gram-negative bacteria
• Intensive care unit.

Bakü’de Yoğun Bakım Ünitelerinden Gönderilen Kan Kültürlerinde İzole Edilen Gram Negatif Bakterilerin Sıklığı ve Antibiyotik Direnç Düzeyleri: Çok Merkezli Bir Çalışma

Abstract

Yoğun bakım ünitelerinde morbidite ve mortalite oranlarındaki artış, büyük ölçüde hastane kaynaklı enfeksiyonlardan kaynaklanmakta olup, günümüzde sağlık sistemlerini tehdit eden en önemli küresel sorunlardan biri olarak kabul edilmektedir. Bu çalışma, yoğun bakım ünitelerinde yatan hastalardan alınan kan kültürü örneklerinden izole edilen Gram negatif bakterilerin tanımlanmasını ve bu bakterilerin antibiyotiklere karşı duyarlılık düzeylerinin sistematik olarak değerlendirilmesini amaçlamaktadır. Bu çalışmaya Bakü’de (Azerbaycan) bulunan üç büyük hastanenin Yenidoğan, Çocuk ve Erişkin yoğun bakım ünitelerinde yatan hastalardan alınan kan kültürü örnekleri dahil edilmiştir. Laboratuvarımıza gönderilen hemokültür şişeleri öncelikle BACT/ALERT 3D 60 (BIOMERIEUX, Fransa) otomatik sistemine yerleştirilmiştir. Cihazdan pozitif sinyal veren örnekler, uygun besiyerlerinde inkübe edilerek üreme olan kültürlerden mikroorganizmalar izole edilmiştir. Bakteri tanımlamaları VITEK 2 Compact sistemi (BioMérieux, Fransa) ile gerçekleştirilmiştir. Antibiyotik duyarlılıkları VITEK 2 Compact (BioMérieux, Fransa) sistemiyle çalışılmış ve “European Committee on Antimicrobial Susceptibility Testing” (EUCAST) kriterlerine göre değerlendirilmiştir. Toplam 2250 kan kültürü örneğinden 1226 (%54.5) mikroorganizma izole edilmiştir. Mikrobiyal üremelerin 759’u (%61.9) Gram pozitif bakteri, 385’i (%31.4) Gram- negatif bakteri ve 82’si (%6.7) maya olarak tanımlanmıştır. En sık izole edilen Gram negatif bakteriler ise sırasıyla; Serratia marcescens (n=76, %19.7), Klebsiella pneumoniae (n=68, %17.7) ve Acinetobacter spp. (n=47, %12.2) olmuştur. Yüksek direnç oranları, izole edilen türler arasında Acinetobacter baumannii’de (%80.9 siprofloksasin), K. pneumoniae’da (%82.4 siprofloksasin), Enterobacter spp.’de (%68.4 sefotaksim), Serratia spp.’de (%75.0 imipenem) ve S. marcescens’te (%64.5 sefotaksim ve siprofloksasin) belirlenmiştir. Çalışmamızda, hastanelerin kritik birimlerinden izole edilen Gram negatif suşlar arasında belirgin düzeyde yüksek antibiyotik direnç oranları saptanmış olup, siprofloksasine karşı direnç Acinetobacter spp. izolatlarında %82.7 ve Klebsiella pneumoniae izolatlarında %82.4 olarak belirlenmiştir. Ayrıca karbapenemlere karşı direnç Serratia spp. izolatlarında imipeneme %75.0 düzeyinde, sefotaksime karşı direnç ise Enterobacter spp. izolatlarında %75.7 olarak saptanmıştır. Bu sonuçlar, Bakü’de antibiyotik direncinin hastane enfeksiyonları yönetiminde ciddi bir tehdit oluşturduğunu göstermektedir. Bu nedenle, Azerbaycanda, özellikle de Bakü’de, etkin enfeksiyon kontrol önlemlerinin uygulanması ve akılcı antibiyotik kullanımının sağlanması amacıyla sürekli direnç izlemi ve kapsamlı stratejilerin hayata geçirilmesi büyük önem taşımaktadır.

Keywords

• Antimikrobiyal duyarlılık
• Çoklu ilaç direnci (MDR)
• Karbapenem direnci
• Gram-negatif bakteriler
• Yoğun bakım ünitesi.

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