Acute pancreatitis (AP) continues to cause significant morbidity and mortality, especially when it leads to infected pancreatic necrosis (IPN). Modern treatment of IPN frequently involves prolonged courses of antibiotics in combination with minimally invasive therapies. This study aimed to update the existing evidence base by identifying the pathogens causing IPN and therefore aid future selection of empirical antibiotics.

Clinical data, including microbiology results, of consecutive patients with IPN undergoing minimally invasive necrosectomy at our institution between January 2009 and July 2016 were retrospectively reviewed.

The results of 40 patients (22 males and 18 females, median age 60 years) with IPN were reviewed. The etiology of AP was gallstones, alcohol, dyslipidemia and unknown in 31, 2, 2 and 5 patients, respectively. The most frequently identified microbes in microbiology cultures were Enterococcus faecalis and faecium (22.5% and 20.0%) and Escherichia coli (20.0%). In 19 cases the cultures grew multiple organisms. The antibiotics with the least resistance amongst the microbiota were teicoplanin (5.0%), linezolid (5.6%), ertapenem (6.5%), and meropenem (7.4%).

The carbapenem antibiotics, ertapenem and meropenem provide good antimicrobial cover against the common, mainly enteral, microorganisms causing IPN. Culture and sensitivity results of acquired samples should be regularly reviewed to adjust prescribing and monitor for emergence of resistance.