Risk Factors and Outcomes of Community Onset Pseudomonas aeruginosa Bacteraemia in Two Malaysian District Specialist Hospitals

Introduction: Despite growing number of community onset (CO) Pseudomonas aeruginosa bacteraemia, there is only a dearth of district hospital-based researches examining this significant infection which is associated with high mortality. The objectives of this study were as following: (1) to determine the risk factors of CO Pseudomonas aeruginosa bacteraemia, (2) to compare the 30day mortality rate between Pseudomonas aeruginosa and Escherichia coli bacteraemia and (3) to identify the predictors of 30-day mortality for CO gram negative bacteremia. Materials and Methodology: We performed a retrospective case control study in Hospital Seri Manjung and Hospital Teluk Intan, Perak, Malaysia. Pseudomonas aeruginosa bacteraemia cases that occurred between 1st January 2015 to 31st December 2019 were included, whilst Escherichia coli bacteraemia cases that occurred within the same period were recruited successively until 1:2 case control ratio was achieved. Subjects below 12-year-old and subjects with polymicrobial bacteraemia were excluded. Demographic, clinical and treatment data were collected using pre-tested data collection forms by trained investigators. The data were analysed using SPSS version 20.0. Results: A total of 61 patients with Pseudomonas aeruginosa bacteraemia and 122 patients with Escherichia coli bacteraemia were included. Multiple logistic regression analysis identified following as independent predictors of CO Pseudomonal bacteraemia: recent admission in the last three months, regular haemodialysis, immunosuppressive therapy in the past 30 days, chronic wound/pressure sore at presentation and indwelling urinary catheter at presentation. The 30-day mortality rate was 34.4% in subjects with Pseudomonas aeruginosa bacteraemia and 27.0% in those with Escherichia coli bacteraemia (p=0.302). Predictors of 30-day mortality for community onset gram negative bacteraemia in multiple logistic regression were as follow: older age, underlying solid tumours, neutropaenia at presentation, in-patient mechanical ventilation and in-patient nasogastric tube insertion. Discussion/Conclusion: In the present study, pseudomonal bacteraemia was proven to be rare occurrence as only 61 episodes of CO pseudomonal bacteraemia were recorded over a span of five years period in two district hospitals. Nevertheless, pseudomonal bacteraemia still poses an existential threat as it is associated with high morbidity and mortality. Our data revealed that recent admission, regular hemodialysis, immunosuppressant use, chronic wound and indwelling urinary catheter to be significantly associated with pseudomonal bacteraemia. Haematological malignancy, solid tumours and neutropenia, which are well established risk for pseudomonal bacteraemia was not associated with increased risk of pseudomonal infection in this report. The foremost cause of this discrepancy would be that previous studies were conducted in tertiary hospital where there was a high burden of haematooncological subjects. The intuitive concept that appropriate empirical antibiotics would lead to better survival in gram negative bacteraemia was not substantiated in this report. On the contrary, we identified receipt of inappropriate empirical antibiotics which was switched later was revealed to be a predictive factor for survival. This contradictory observation emphasizes that appropriate empirical antibiotics is not the sole determinants of survival as sepsis survival involves an inter-play of multiple factors. In our opinion, we emphasize that the enthusiasm of choosing appropriate empirical antibiotics should not overshadow the importance of timely fluid resuscitation, sepsis source control, nutrition therapy, as well as judicious use of blood products and life support in intensive care unit which deserve equal attention. Overall, pseudomonal bacteraemia clinical characteristics in this study differ from previous researches undertaken in tertiary hospitals. Interestingly, observations from our data did not support the preconceived notion that Pseudomonas aeruginosa bacteraemia and delayed appropriate antibiotics were more commonly associated with increased odds of mortality. In fact, host factors display a higher influence on the mortality rate as opposed to type of infections and timeliness of antibiotics. Lastly, we recommend judicious use of anti-pseudomonal antibiotics among at risk groups keeping in mind that community onset pseudomonal bacteraemia remain a rare condition in district setting. [Disclaimer: Abstract text might vary slightly from what is displayed in the e-poster]