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.
Highlights
The growing resistance of bacteria isolated from inpatients to antibiotics is a serious problem all over the world, but in certain regions it reached an alarming level, e.g. in Eastern Europe and Latin America, where 37.7% and 19.1% of isolates were Extended-spectrum β-lactamases (ESBL) – producing Gram– negative microorganisms, respectively [1]
Our study showed that pandrug-resistant Pseudomonas aeruginosa was present in the environment of the intensive care units (ICUs) because hygiene was not stringently and continuously kept
Since all isolates in the ICU that we investigated, were pandrugresistant to antimicrobials, it seems that this ICU already came to the bottom of the spiral, after passing numerous circles
Summary
The growing resistance of bacteria isolated from inpatients to antibiotics is a serious problem all over the world, but in certain regions it reached an alarming level, e.g. in Eastern Europe and Latin America, where 37.7% and 19.1% of isolates were Extended-spectrum β-lactamases (ESBL) – producing Gram– negative microorganisms, respectively [1]. Differentiating colonization from infection is not straightforward, and sometimes antibiotics are prescribed unnecessarily if a clinician relies only on susceptibility report from microbiology lab [4], further promoting antimicrobial resistance. Among the actions undertaken by hospital management in this direction one was to make a survey of the susceptibility of isolates of Pseudomonas aeruginosa to ceftolozane/tazobactam from the patients in central ICU. At the beginning of 2018 the first reports came from the hospital’s microbiology lab, all related to Pseudomonas aeruginosa isolated from tracheal aspirates. Both clinicians and hospital management were confused with the results - all isolates (at least a dozen) were pandrug-resistant to all tested antibiotics, including ceftolozane/tazobactam, carbapenems, piperacillin/tazobactam and colistin. The reports were based only on isolation of Pseudomonas of aeruginosa (without a threshold), and not on quantitative endotracheal aspirate [5, 6], and ceftolozane/ tazobactam was never used previously in this hospital, a doubt on efficacy of this new antibiotic was raised among the clinicians and threatened to hamper its introduction in clinical practice
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