(P-470) Antibiotic Resistance Pattern and Treatment Outcomes Among Empyema Thoracis Patients: A Cross-sectional Study

Background: Empyema thoracis is an infectious disease which causes the accumulation of frank pus in the pleural space of lungs.

Objectives: This study aims to analyze the spectrum of microorganisms, antibiotic resistance pattern, and treatment outcomes among empyema thoracis patients. We also analyzed the factors associated with unsuccessful treatment outcome and duration of hospital stay.

Methods: This was a descriptive, cross-sectional study carried out in the Pulmonology Ward of the Bahawal Victoria Hospital, Pakistan. All empyema thoracis patients who were registered at the study site from October 2019 to September 2020 were included in the study. Medical records of the patients were used to obtain their socio-demographic and clinical data. The outcome variables included; spectrum of microorganisms, antibiotic resistance pattern, and treatment outcomes. Treatment outcomes were reported as; treatment completed with clinical improvement, no clinical improvement, loss to follow up and death. Multivariate regression analysis was used to analyze the factors associated with duration of hospital stay and unsuccessful treatment outcome.

Results: A total 110 patients were included in the study. Most of the patients (n= 73, 66.4%) were treated with piperacillin/ tazobactam alone and in combination with either one or more than one antibiotics as an empiric therapy. Culture was positive in 58 (52.7%) patients and the most commonly identified organisms included, gram-negative Pseudomonas aeruginosa (n = 20; 18.8%) and Klebsiella (n= 11, 10%) followed by same proportion of E. coli. These bacterial isolates showed high level of resistance against empiric therapy, while these showed low level of resistance against amoxicillin, clarithromycin, colistin, tigecycline, vancomycin etc. In this study, 82 (74.5%) patients successfully completed the treatment, while 12 (11%) showed no clinical improvement, 5 (4.5%) lost to follow up and 11 (10%) died. In multivariate binary logistic regression analysis, none of the patient attributes were significantly associated with unsuccessful treatment outcome, while in multivariate linear regression analysis, the factors significantly associated with duration of hospital stay included; duration of symptoms less than two weeks prior to admission (p-value= 0.008, beta= -0.247) and resistance to five antibiotic classes (p-value= 0.02, beta= 0.280).

Conclusions: Close to 25% of the patients did not complete the treatment successfully. Commonly identified bacterial isolates showed high level of resistance against the broad-spectrum antibiotics used as an empiric therapy. This is alarming. However, better sensitivity of common bacterial isolates against standardized first-line treatment for empyema thoracis is promising.