Hospital Pharmacology (Jan 2019)
Pandrug-resistant Pseudomonas aeruginosa isolated from qualitative endotracheal aspirate could rather be contaminant than causative agent of respiratory infections in intensive care unit patients: Case study
Abstract
Introduction: Differentiating colonization from infection is not straightforward, and sometimes antibiotics are prescribed unnecessarily if a clinician relies only on susceptibility report from microbiology lab, further promoting antimicrobial resistance. Aim: The aim of our study was to investigate whether pandrug-resistant Pseudomonas aeruginosa (PA) isolated from qualitative endotracheal aspirates of ICU patients was primarily external colonization from environmental reservoirs. Subjects and Methods: An instrumental case study was conducted using qualitative research methodology. An ICU with level 2 or 3 of intensive care from Clinical Center Kragujevac, Serbia, was chosen for the case, and research questions were triangulated by direct observation, interviewing personnel of the ICU and by epidemiological survey. Results: Pandrug-resistant PA was present in environment of the ICU because hygiene was not stringently kept. It eventually arrived to respiratory circuits of mechanically ventilated patients and gradually descended to endotracheal tube and trachea. Reliance on qualitative endotracheal aspirate in patients with suspected respiratory tract infection led to diagnosing colonization as infection in 50% of cases with isolation of PA. Inadequate hygiene and avoidance of aseptic working techniques together with understaffing and insufficient funding of the ICUs leads to contamination of personnel and environment with Pseudomonas aeruginosa coming from ill patients. It is then cross-transferred to other patients, who are over-treated with reserve antibiotics due to low specificity of qualitative microbiological analyses and the fact that 50% of patients are only colonized. Conclusions: Pressure made by antimicrobial treatment of colonization creates at first multi drug-, and then pandrug-resistant clones of PA which gradually populate environment of the ICU, becoming serious threat for new patients. This vicious spiral could be broken by improvement of hygiene, provision of enough trained personnel and necessary materials, continuous control of personnel's compliance to working standards for ICUs and by introduction of quantitative microbiological analysis of samples.
