Microbial Spectrum in Infected Pancreatic Necrosis: An Analysis From Endoscopic Ultrasound Guided Drainage

Abstract

Introduction: Necrotizing pancreatitis is a potentially life-threatening condition. Necrosis can remain sterile or infected leading to infected pancreatic necrosis (IPN) with a mortality rate as high as 30% - 50%. Antibiotics play an important role in IPN management. However, inappropriately chosen broadspectrum antibiotics will lead to the development of resistance over time. Therefore, microbiological analysis of the necrosum will help in selecting the appropriate antibiotics. Common causative organisms are gram-negative; however, some recent studies show the change in predominance to gram-positive organisms which has been attributed to the use of prophylactic antibiotics targeting gram negatives. Despite this, some reports from India and China continued to show predominant gram-negative infections. The primary aim was to identify the microbial spectrum in the IPN with the cultures obtained from Endoscopic Ultrasound (EUS) guided drainage at Asian Institute of Gastroenterology (AIG), a tertiary care center in India. Methods: A retrospective analysis of prospectively collected data of patients diagnosed with IPN at AIG from October 2013 to December 2014 was included in the study. IPN was diagnosed using computed tomography, as per revised Atlanta classification. All patients underwent EUS guided drainage of the IPN. The first aspirated sample from the pancreatic fluid collection on puncture with the 19G needle was sent for microbial analysis. The subsequent drainage procedure was completed with placement of either multiple plastic or FCSEMS. Results: A total of 113 patients (93 males, 20 females) aged 11-69 years were included in the study. Aspirates from 45 of 113 (40%) patients showed positive cultures. 38 out of 45 positive cultures were polymicrobial and 6 were monomicrobial. The most common organisms identified in the microbial spectrum were gram negatives and they were seen in 95.5% of the aspirates. The most common bacteria were Escherichia Coli which was seen in 49% of the aspirates followed by Klebsiella (40%). Remaining organisms include Pseudomonas (6%), Acinetobacter (6%) and Citrobacter (4.5%). Gram positives were seen in 2 patients (4.5%) and fungus was seen in 0 patients. Conclusion: While the recent studies demonstrate the predominance of gram-positive organisms in IPN, the findings in our study are contrary to them with gram-negative predominance. Microbial cultures and local antibiogram should be taken into account while treating IPN for better patient outcomes.81_A Figure 1. No Caption available.81_B Figure 2. No Caption available.