Clinical and microbiological characteristics of gram- negative bacteremias in Hacettepe University İhsan Dogramaci Children's Hospital

Bloodstream infections caused by Gram-negative bacteria emerge as an important cause of mortality and morbidity in pediatric clinics. In this study, we aimed that to determine the most isolated Gram-negative bacteria from blood cultures, their resistance and the variation over the years, the epidemiologic changes of bacteria, the differences in the clinical conditions of the patients according to bacteria, and the risk factors that predispose to a Gram-negative bacteremia in pediatric patients. In the study, 412 episodes of 349 patients with Gram-negative bacteriemia and the data of children aged 0-18 years who were hospitalized in Hacettepe University Ihsan Dogramacı Children's Hospital between 2017 and 2021 were retrospectively analyzed. In addition, the data were compared with our previous findings. Of all, 154 (44.2%) were female and 195 (55.8%) were male. The median age was calculated as 12.5 months and 252 (61%) of the patients were under 2 years of age. Of the Gram-negative bacteremia, 43 (10.4%) were community-acquired, and 369 (89.5%) were nosocomial. The most common microorganisms were Klebsiella spp. (43.9%, n=181), E. coli (13.5%, n=56), Acinetobacter spp. (10.6%, n=44), Pseudomonas spp. and Enterobacter spp. (7.2%, n= 30). Carbapenem resistance was present in 27.6% of all Gram-negative bacteria, 41.2% of the bacteria were MDR (multi drug resistance), 13.5% were XDR (extensively drug resistance) and 0.4% were PDR (pandrug resistance). In addition, it was determined that carbapanem resistance increased by 2% over the years. The most common underlying diseases were hematological and oncological malignancies (22.9%), primary immunodeficiencies (12.6%), and cardiovascular diseases (11.7%). The most common risk factors for the development of Gram-negative bacteremia were the presence of a central venous catheter (77%), hospitalization in the intensive care unit (67%) and the use of broad-spectrum antibiotics within the last month (45.6%). Infection-related mortality was 15.7% and overall mortality rate was 28%. Being hospitalized in the ICU, presence of central venous catheter, receiving mechanical ventilator support, need for inotropic medication, and receiving peritoneal dialysis support were found to be associated with clinical unresponsiveness and infection-related mortality in patients with Gram- negative bacteremia. The increase in multi-resistant Klebsiella spp. seems to be one of the biggest obstacles ahead in our fight against nosocomial infections. Increasing carbapenem resistance in Gram-negative bacteria over the years affects both the clinical response of bloodstream infections and increases mortality. Close follow-up of these local data is very important both in the fight against increasing resistance and in determining the ideal empirical antimicrobial treatments.