2178. Microbiological Diagnosis of Ventilator Associated Pneumonia Caused by Gram Negative Bacterias Resistant to Carbapenems Using a Fast Molecular Method.

Abstract

Abstract Background Ventilator-associated pneumonia (VAP) is one of the most important healthcare-associated infections. The burden of VAP regard morbility and mortality is significant. Most of the etiological agents of VAP are Gam negative organisms and a proportion of them could be resistant to carbapenems. GeneXpert Carba-R is a molecular test originally designed to detect rectal colonization by microorganisms expressing resistance genes to carbapenems (NDM, KPC, VIM, IMP, OXA-48). The aim of this study was to determine how useful is to use GeneXpert Carba-R in clinical samples of aspirates of bronchial secretion in patients with VAP. Methods This is a prospective observational study in a sample of patients that developed VAP at the intensive care unit in Hospital Dr. Fernando Vélez Paiz (Managua, Nicaragua) between April 2021 and December 2021. The diagnostic criterias of the CDC for VAP were used. Samples of bronchoalveolar secretions were processed using GeneXpert Carba-R and by bacteriological conventional culture. The molecular method GeneXpert Carba-R was able to detect genes as NDM, KPC, VIM, OXA-48 and IMP. The presence of any of them was considered as microorganism resistant to carbapenems and the result was correlated with the final identification and susceptibility pattern obtained in the bacteriological culture using the system Vitek2. Results A total of 45 patients were recruited in the study. Twenty-seven patients (60%) had at least one gene of resistance detected by GeneXpert Carba-R. The most frequent gene detected was NDM (81%). The cultures identified Acinetobacter baumannii (36%), Klebsiella pneumoniae (27%), and Pseudomonas aeruginosa (23%). The sensitivity and the specificity of the GeneXpert Carba-R for the diagnosis of a organism resistant to carbapenems were 86.7% (CI95%: 71.1-95-8) and 93.3% (CI95%: 80.7%-100%) respectively. The risk factors to develope a VAP with an organism expressing a gene of resistance were diabetes mellitus, extended staying in ICU, SOFA score > 2 points, mechanical ventilation ≥ 8 days, and to have had septic shock at the admission. Correlation between GeneXpert Carba-R and bacteriological culture for microbiological diagnosis of VAP caused by carbapenem-resistant bacterias. Conclusion To process GeneXpert Carba-R directly of bronchoalveolar secretions was useful in the diagnosis of VAP caused by microorganisms resistant to carbapenems. The most frequent gene detected was NDM. Disclosures All Authors: No reported disclosures.