Microbial Epidemiology of Acute and Perforated Appendicitis in Adults Treated with Appendectomy or Percutaneous Drain
Author(s):
Sinong Qian; Georgia Vasileiou; Andreas Larentzakis; Rishi Rattan; Tanya Zakrison; Chris Dodgion; Haytham Kaafarani; Martin Zielinski; Nicholas Namias; Daniel Yeh
Background:
A recent observational study described significant practice variation in antibiotic treatment for appendicitis, ranging from short-course narrow spectrum to long-course broad-spectrum. Appropriate empiric antibiotic selection depends upon a sound understanding of the most likely organisms involved in the infection. To our knowledge, there has not been a recent epidemiologic description of the microbial spectrum in adults in the United States. We sought to describe the modern microbial epidemiology of acute and perforated appendicitis in adults in order to help inform empiric coverage and support antibiotic stewardship initiatives.
Methods:
In this post hoc analysis of a prospective, multicenter (n=28), observational study of appendicitis in American adults conducted from 01/17-06/18, we included all subjects with a positive microbiologic culture during primary or secondary (rescue after medical failure) appendectomy or percutaneous drainage.
Results:
Out of 3,597 total subjects, 3,471 subjects underwent intervention; 230 (7%) had cultures performed, and 179/230 (78%) had positive results. Cultures were less likely to be positive in low-grade (AAST EGS Operative Grade 1 or 2) compared to high-grade (AAST EGS Operative Grade 3, 4, or 5) appendicitis, 2/18 (11%) vs. 61/70 (87%), p< .001. The distribution of microbial growth by intervention (Table 1) and AAST EGS Operative Grade (Table 2) are reported.
Conclusions:
Culturing low-grade appendicitis is low yield. E. coli is the most commonly cultured microbe in acute and perforated appendicitis. The bacterial epidemiology for appendicitis subjects selected for percutaneous drainage differs from those selected initially for operative treatment. These data help inform empiric coverage for both antibiotics alone and antibiotics as an adjunct to operative or percutaneous intervention.
Microbial Epidemiology of Acute and Perforated Appendicitis in Adults Treated with Appendectomy or Percutaneous Drain
Author(s):
Christopher Towe, Nathaly Llore, Nathalie Hirsch, Jessica Donington, Harvey Pass, Vanessa Ho, NYU Langone Medical Center
Background: Empyema can result as a complication of bacterial pneumonia or thoracic surgery procedures with mortality as high as 15%. Empyema pathogens are poorly described in the modern era. Greater understanding of common pathogens and risk factors is required to improve empiric treatment. The primary aim of this study is to describe the microbiology of empyema in the modern era.
Hypothesis: We hypothesize that parapneumonic empyema (PNE) and post-surgical empyema (PSE) will be clinically and microbiologically distinct.
Methods: All patients with positive pleural cultures between 4/2007 and 6/2012 were identified from microbiological records. Patient demographics, clinical course and microbiological information were collected. Each acute empyema was classified as PNE or PSE and differences between groups were assessed using the Chi-square test.
Results: A total of 227 microorganisms from 28 genus classes were isolated from 125 patients (74 (64%) male, mean age 61). 120 (97%) required drainage and/or decortication, while 5 were treated with antibiotics alone. Common comorbidities included: a history of immunosuppression (29%), diabetes (19%), and renal disease (14%). Mortality was 15%. Half (47.7%) of the index cultures were polymicrobial. 152 isolates (67%) were gram positive, 56 (25%) were gram negative, 16 (7%) were fungal, and 3 (1%) were unclassified. Only 7% of isolates were obligate anaerobes. The most common organisms were Streptococcus spp (27%) and Staphylococcus spp (25%), followed by Enterococcus spp (9%), Candida (6%), and Pseudomonas (6%). Of 31 isolates of S. aureus, 14 (45%) were methicillin resistant. 29% of the infections were postoperative. Patients with PSE were less likely to have had a preceding pneumonia (28% vs 65%, p<0.05). Patients with PSE had a slightly higher incidence of gram-negative pathogens but this did not reach statistical significance (40% vs 26%, p=0.1). There was no difference in outcome between the PNE and PSE patients. Conclusions: A wide variety of pathogens were isolated from infected pleural cultures. The most common pathogens isolated were aerobes and gram positives. Polymicrobial infections were common. There was no significant difference in clinical course or pathogens isolated from parapneumonic and post-surgical empyema.