Ventilator-associated lower respiratory tract infections: Etiology and diagnosis

Objective. To review a literature published over the past 5 years and our own data on the etiology of lower respiratory tract infections (LRTI), antimicrobial resistance and its relationships between sepsis and choice of appropriate antibiotic therapy. Materials and methods. National Nosocomial Infections Surveillance (NNIS) criteria were used to diagnose LRTI. A review of the articles regarding LRTI from the Russian and international English language journals published over 6 years was performed. Identification of microorganisms was performed by culture over the period of 2003-2013;since 2014, MALDI-TOF MS method was used for this purpose. Results. Despite the ongoing policy to limit the use of antimicrobial therapy in the ICUs, there is an increase in carbapenemase-producing isolates in the ICUs from 2.2% (2018) to 11.7% (2020, 9 months). Along with the trend to increase in carbapenemase-producing pathogens causing LRTI, their variability is also increasing. In particular, it applies to strains producing carbapenemases OXA-48 or combination of OXA- 48 with KPC;with the trend to combined production of carbapenemase beginning at 2019. Conclusions. Carbapenemase producers are becoming more widespread in the ICU settings, including the lower respiratory tract in mechanically ventilated patients. Practitioners didn’t get used to associate VAP with the Sepsis-3 criteria. The changes in etiology include the increased rate of carbapenem-resistant Enterobacterales and non-fermenting Gram-negative bacteria, primarily Acinetobacter spp., in Russia. It’s due to improved quality of respiratory support and increased consumption of carbapenems, tigecycline and polymyxins. Significant increase of OXA-48-producing pathogens is likely to be associated with a poor compliance with temporary guidelines on COVID-19 with regard to antibiotic therapy. © 2021, Interregional Association for Clinical Microbiology and Antimicrobial Chemotherapy. All rights reserved.