Peritoneal fluid culture in appendicitis: review in changing times

Management of intra-abdominal infections: recommendations by the Italian council for the optimization of antimicrobial use

Intra-abdominal infections (IAIs) are common surgical emergencies and are an important cause of morbidity and mortality in hospital settings, particularly if poorly managed. The cornerstones of effective IAIs management include early diagnosis, adequate source control, appropriate antimicrobial therapy, and early physiologic stabilization using intravenous fluids and vasopressor agents in critically ill patients. Adequate empiric antimicrobial therapy in patients with IAIs is of paramount importance because inappropriate antimicrobial therapy is associated with poor outcomes. Optimizing antimicrobial prescriptions improves treatment effectiveness, increases patients' safety, and minimizes the risk of opportunistic infections (such as Clostridioides difficile) and antimicrobial resistance selection. The growing emergence of multi-drug resistant organisms has caused an impending crisis with alarming implications, especially regarding Gram-negative bacteria. The Multidisciplinary and Intersociety Italian Council for the Optimization of Antimicrobial Use promoted a consensus conference on the antimicrobial management of IAIs, including emergency medicine specialists, radiologists, surgeons, intensivists, infectious disease specialists, clinical pharmacologists, hospital pharmacists, microbiologists and public health specialists. Relevant clinical questions were constructed by the Organizational Committee in order to investigate the topic. The expert panel produced recommendation statements based on the best scientific evidence from PubMed and EMBASE Library and experts' opinions. The statements were planned and graded according to the Grading of Recommendations Assessment, Development and Evaluation (GRADE) hierarchy of evidence. On November 10, 2023, the experts met in Mestre (Italy) to debate the statements. After the approval of the statements, the expert panel met via email and virtual meetings to prepare and revise the definitive document. This document represents the executive summary of the consensus conference and comprises three sections. The first section focuses on the general principles of diagnosis and treatment of IAIs. The second section provides twenty-three evidence-based recommendations for the antimicrobial therapy of IAIs. The third section presents eight clinical diagnostic-therapeutic pathways for the most common IAIs. The document has been endorsed by the Italian Society of Surgery.

Intra-abdominal infections survival guide: a position statement by the Global Alliance For Infections In Surgery

Intra-abdominal infections (IAIs) are an important cause of morbidity and mortality in hospital settings worldwide. The cornerstones of IAI management include rapid, accurate diagnostics; timely, adequate source control; appropriate, short-duration antimicrobial therapy administered according to the principles of pharmacokinetics/pharmacodynamics and antimicrobial stewardship; and hemodynamic and organ functional support with intravenous fluid and adjunctive vasopressor agents for critical illness (sepsis/organ dysfunction or septic shock after correction of hypovolemia). In patients with IAIs, a personalized approach is crucial to optimize outcomes and should be based on multiple aspects that require careful clinical assessment. The anatomic extent of infection, the presumed pathogens involved and risk factors for antimicrobial resistance, the origin and extent of the infection, the patient's clinical condition, and the host's immune status should be assessed continuously to optimize the management of patients with complicated IAIs.

The role of intraoperative swab during appendectomy in patients with uncomplicated and complicated appendicitis

INTRODUCTION

Bacteria play an important role not only in pathogenesis of appendicitis but also in the postoperative course of patients. However, the usefulness of an intraoperative swab during appendectomy is controversial. The primary aim of this study was to investigate the impact of intraoperative swab during appendectomy on the postoperative outcome in patients with uncomplicated and complicated appendicitis.

METHODS

A retrospective analysis was conducted on a consecutive series of 1570 adult patients who underwent appendectomy for acute appendicitis at the University Hospital Erlangen between 2010 and 2020. Data regarding the intraoperative swab were collected and analyzed for the entire cohort as well as for patients with uncomplicated and complicated appendicitis.

RESULTS

An intraoperative swab was taken in 29% of the cohort. The bacterial isolation rate in the obtained intraoperative swabs was 51%, with a significantly higher rate observed in patients with complicated appendicitis compared to those with uncomplicated appendicitis (79% vs. 35%, p < 0.001). The presence of a positive swab was significantly associated with worse postoperative outcomes, including higher morbidity, increased need for re-surgery, and longer hospital stay, when compared to patients without a swab or with a negative swab. A positive swab was an independent risk factor for postoperative morbidity (OR 9.9 (95% CI 1.2-81.9), p = 0.034) and the need for adjustment of postoperative antibiotic therapy (OR 8.8 (95% CI 1.1-72.5), p = 0.043). However, a positive swab resulted in postoperative antibiotic therapy adjustment in only 8% of the patients with bacterial isolation in the swab.

CONCLUSION

The analysis of swab samples obtained during appendectomy for acute appendicitis can help identify patients at a higher risk of a worse postoperative outcome. However, the frequency of antibiotic regime changes based on the swab analysis is low.

Bacterial pathogens in pediatric appendicitis: a comprehensive retrospective study

Background

Appendicitis is a frequent condition, with peak incidences in the second decade of life. Its pathogenesis is under debate, but bacterial infections are crucial, and antibiotic treatment remains essential. Rare bacteria are accused of causing complications, and various calculated antibiotics are propagated, yet there is no comprehensive microbiological analysis of pediatric appendicitis. Here we review different pre-analytic pathways, identify rare and common bacterial pathogens and their antibiotic resistances, correlate clinical courses, and evaluate standard calculated antibiotics in a large pediatric cohort.

Method

We reviewed 579 patient records and microbiological results of intraoperative swabs in standard Amies agar media or fluid samples after appendectomies for appendicitis between May 2011 and April 2019. Bacteria were cultured and identified via VITEK 2 or MALDI-TOF MS. Minimal inhibitory concentrations were reevaluated according to EUCAST 2022. Results were correlated to clinical courses.

Results

Of 579 analyzed patients, in 372 patients we got 1330 bacterial growths with resistograms. 1259 times, bacteria could be identified to species level. 102 different bacteria could be cultivated. 49% of catarrhal and 52% of phlegmonous appendices resulted in bacterial growth. In gangrenous appendicitis, only 38% remained sterile, while this number reduced to 4% after perforation. Many fluid samples remained sterile even when unsterile swabs had been taken simultaneously. 40 common enteral genera were responsible for 76.5% of bacterial identifications in 96.8% of patients. However, 69 rare bacteria were found in 187 patients without specifically elevated risk for complications.

Conclusion

Amies agar gel swabs performed superior to fluid samples and should be a standard in appendectomies. Even catarrhal appendices were only sterile in 51%, which is interesting in view of a possible viral cause. According to our resistograms, the best in vitro antibiotic was imipenem with 88.4% susceptible strains, followed by piperacillin-tazobactam, cefuroxime with metronidazole, and ampicillin-sulbactam to which only 21.6% of bacteria were susceptible. Bacterial growths and higher resistances correlate to an elevated risk of complications. Rare bacteria are found in many patients, but there is no specific consequence regarding antibiotic susceptibility, clinical course, or complications. Prospective, comprehensive studies are needed to further elicit pediatric appendicitis microbiology and antibiotic treatment.

Appendicitis Inflammatory Response Score in Acute Appendicitis: A Study at a Tertiary Care Center in North India

Introduction

Appendicitis is a common cause of acute abdominal pain. The diagnosis is eminently clinical and the cause is surgically correctable. However, a decision of surgery based on the clinical presentation only has a 15%-30% chance of the removal of a normal appendix. Thus, the diagnosis involves a corroboration of clinical, laboratory, and radiological findings. Appendicitis scoring systems can be considered to expedite the diagnostic and decision-making process.

Aim

The present study was conducted to study the efficacy of Appendicitis Inflammatory Response (AIR) score in the diagnosis of acute appendicitis and its correlation with the histopathological findings.

Materials and Methods

A cross-sectional study was conducted at a tertiary care center in North India comprising patients who presented to the surgery department with a provisional diagnosis of acute appendicitis and required appendectomy.

Results

Appendicitis was histopathologically proven in 54 patients. Patients with an AIR score ≥5 were 2.18 times more likely to have appendicitis. The probability of having appendicitis with AIR score ≥5 was 92.16% (positive predictive value). The diagnostic accuracy of AIR score was 82.81%.

Conclusion

AIR score has a high sensitivity and positive predictive value in the diagnosis of acute appendicitis. It is a quick and convenient system for clinical evaluation of patients in primary care or peripheral hospitals where advanced facilities such as USG scan or CT scan are not available all the time. The application of this scoring system definitely improves diagnostic accuracy and reduces negative appendectomy rate.

Antibiotic resistance is common in the cultures of intraabdominal abscess drainage after appendectomy

INTRODUCTION

Intraabdominal abscesses (IAA) are a common complication following appendectomy. Empiric antibiotic regimens may fail to prevent IAA due to changes in bacterial resistance. We aim to describe the bacteriology of pediatric patients requiring drainage of an IAA after an appendectomy for appendicitis.

METHODS

We performed a retrospective study of patients ≤18 years who underwent percutaneous drainage of an IAA following appendectomy a single U.S. children's hospital between 2015 and 2018. Patient demographics, appendicitis characteristics, antibiotic regimens, and culture data were collected.

RESULTS

In total, 71 patients required drainage of an IAA of which 48 (67%) were male, the average age was 9.81 (SD 3.31) years and 68 (95.7%) having complicated appendicitis. Ceftriaxone/metronidazole was the most common empiric regimen prior to IAA drainage occurring in 64 (90.1%) patients. IAA cultures isolated organisms in 34 (47.9%) patients. Of those with positive cultures, 17 (50%) cases demonstrated an antimicrobial resistant organism. Most notably, 20% of Escherichia coli was resistant to the empiric regimen. Empiric antimicrobial regimens did not appropriately cover 92.3% of Pseudomonas aeruginosa cultures or 100% of Enterococcus species cultures. Antimicrobial regimens were changed following IAA drainage in 30 (42.2%) instances with 23 (32.4%) instances due to resistance in culture results or lack of appropriate empiric antimicrobial coverage.

CONCLUSIONS

IAA culture data following appendectomy for appendicitis frequently demonstrates resistance to or lack of appropriate coverage by empiric antimicrobial regimens. These data support close review of IAA culture results to identify prevalent resistant pathogens along with local changes in resistance.

LEVEL OF EVIDENCE

Level III.

Case report: appendicitis induced Staphylococcus aureus and Klebsiella pneumoniae bacteremia in a young healthy male

Background

Appendicitis is one of the most frequently encountered conditions at the emergency department. Distinction is made between complicated and uncomplicated appendicitis. Complicated appendicitis may cause serious intra-abdominal infection, bacteremia, or sepsis. Emergency health providers should be highly alert to any early signs indicating such complications.

Case presentation

We present the case of a healthy young male with a gangrenous appendicitis, who received antibiotics and underwent appendectomy. Blood cultures showed unequivocal Staphylococcus aureus and concomitant Klebsiella pneumoniae bacteremia requiring prolonged antibiotic treatment and further diagnostic evaluation.

Conclusions

Although rare, appendicitis can cause Staphylococcus aureus and Klebsiella pneumoniae bacteremia with extensive implications for workup and antibiotic management. Our case stresses the importance of obtaining cultures in patients with suspicion of bacteremia given its consequences for clinical management.

Uselessness of microbiological samples in acute appendicitis with frank pus: to collect or not to collect?

INTRODUCTION

Current use of antimicrobial therapy is prophylactic, empirical and broad spectrum. But, the age-old practice of obtaining cultures still remain. The aim of this study was to evaluate bacterial etiology and adequacy of antibiotic prophylaxis in patients diagnosed with acute appendicitis to help determine the utility of intraoperative cultures in guiding clinical decision-making.

MATERIALS AND METHODS

A retrospective analysis of a prospectively constructed database of all patients who underwent appendectomy from September 2013 to November 2016 was performed.

RESULTS

456 patients underwent surgery for acute appendicitis in our academic hospital. 101 patients (22.1%) had intraoperative swabs taken, and the cultures were positive in 57.4% of patients. These 101 patients comprise our study group. The most commonly recovered species were E. coli, Streptococcus spp., Bacteroides fragilis, Enterococcus faecium, Pseudomonas aeruginosa, Klebsiella pneumoniae, and Proteus. In the comparison between positive and negative swab, there were no differences in terms of surgical site infection, deep infection, and in terms of Clavien-Dindo classification. An appropriate empiric therapy was set in 88.5% and inappropriate in 11.5%. No differences in terms of surgical site infection or in length of stay (p = 0.657) were found, with a median of 7 days in both groups.

CONCLUSION

The etiological agents causing peritonitis due to acute appendicitis are predictable and empiric-targeted antibiotic therapy is effective in a high percentage of patients. The postoperative patient outcome may be dependent on the severity of the appendicitis more than on the results of the swab at the time of surgery. In this study, intraoperative culture was not associated with the choice of antibiotics, incidence of SSI, DPI or the length of stay.

Usefulness of intraoperative culture swabs in laparoscopic appendectomy for complicated appendicitis

PURPOSE

Intraabdominal abscess (IAA) is a feared complication after laparoscopic appendectomy (LA) for complicated appendicitis. Benefits of obtaining intraoperative culture swabs (ICS) still remain controversial. We aimed to determine whether ICS modify the rate and management of IAA after LA for complicated appendicitis.

METHODS

A consecutive series of patients who underwent LA for complicated appendicitis from 2008 to 2018 were included. The cohort was divided into two groups: group 1 (G1), with ICS, and group 2 (G2), without ICS. Demographics, operative variables, pathogen isolation, antibiotic sensitivity, and postoperative outcomes were analyzed.

RESULTS

A total of 1639 LA were performed in the study period. Of these, 270 (16.5%) were complicated appendicitis; 90 (33%) belonged to G1 and 180 (67%) to G2. In G1, a higher proportion of patients had generalized peritonitis (G1, 63.3%; G2, 35%; p < 0.01). Seventy-two (80%) patients had positive cultures in G1. The most frequently isolated bacteria were E. coli (66.7%), Bacteroides spp. (34.7%), and Streptococcus spp. (19.4%). In 26 (36%) patients, the initial empiric antibiotic course was modified due to bacterial resistance. The rate of IAA was higher in patients with ICS (G1, 21.1%; G2, 9.4%; p = 0.01). IAA was treated similarly in both groups. A different type of bacteria was isolated in 7 (53.8%) patients with new culture swabs.

CONCLUSIONS

Obtaining ICS in LA for complicated appendicitis with further antibiotic adjustment to the initial pathogen did not lower the incidence of postoperative IAA and did not modify the treatment needed for this complication.

Routine Intraoperative Bacterial Culture May Be Needed in Complicated Appendicitis

Purpose

Choosing the appropriate antibiotic is important for treatment of complicated appendicitis. However, increasing multidrug resistant bacteria have been a serious problem for successful treatment. This study was designed to identify bacteria isolated from patients with complicated appendicitis and reveal their susceptibilities for antibiotics and their relationship with patient clinical course.

Methods

This study included patients diagnosed with complicated appendicitis and examined the bacterial cultures and antimicrobial susceptibilities of the isolates. Data were retrospectively collected from medical records of Kangbuk Samsung Hospital from January 2008 to February 2018.

Results

The common bacterial species cultured in complicated appendicitis were as follows: Escherichia coli (n=113, 48.9%), Streptococcus spp. (n=29, 12.6%), Pseudomonas spp. (n=23, 10.0%), Bacteriodes spp. (n=22, 9.5%), Klebsiella (n=11, 4.8%), and Enterococcus spp. (n=8, 3.5%). In antibiotics susceptibility testing, the positive rate of extended-spectrum beta lactamase (ESBL) was 9.1% (21 of 231). The resistance rate to carbapenem was 1.7% (4 of 231), while that to vancomycin was 0.4% (1 of 231). E. coli was 16.8% ESBL positive (19 of 113) and had 22.1% and 19.5% resistance rates to cefotaxime and ceftazidime, respectively. Inappropriate empirical antibiotic treatment (IEAT) occurred in 55 cases (31.8%) and was significantly related with organ/space surgical site infection (SSI) (7 of 55, P=0.005).

Conclusion

The rate of antibiotic resistance organisms was high in community-acquired complicated appendicitis in Koreans. Additionally, IEAT in complicated appendicitis may lead to increased rates of SSI. Routine intraoperative culture in patients with complicated appendicitis may be an effective strategy for appropriate antibiotic regimen.

An Evaluation of Treatment Patterns and Associated Outcomes Among Adult Hospitalized Patients With Lower-Risk Community-Acquired Complicated Intra-abdominal Infections: How Often Are Expert Guidelines Followed?

Background

Expert guidelines discourage use of antipseudomonal β-lactams and fluoroquinolones in lower-risk patients with community-acquired complicated intra-abdominal infection (CA cIAI). Compliance with these recommendations across US hospitals is unclear. This study sought to determine treatment patterns and associated outcomes among adult hospitalized lower-risk patients with CA cIAI.

Methods

A study using data from the Premier Healthcare Database (10/2015–12/2017) was performed. Inclusion criteria: age ≥18 years; hospitalized; had a cIAI at admission; and received antibiotics within the first 4 hospital days. Patients were excluded if they were high risk, were transferred from another health care facility, had a recent hospital admission, or received dialysis within 30 days of admission. Empiric antibiotic treatment patterns and associated outcomes were quantified.

Results

Overall, 46722 (66%) patients with cIAIs met the lower-risk CA IAI study criteria. Among lower-risk CA IAI patients, the mean (SD) age was 53.4 (18.2) years, and 71% had a Charlson Comorbidity Index score of 0. The most common diagnosis was acute appendicitis with peritonitis (59.7%). Among lower-risk CA IAI patients, 54% received piperacillin/tazobactam, 20% received a fluoroquinolone (FQ), 11% received ceftriaxone, and 7% received ampicillin/sulbactam. Overall, the median hospital length of stay was 4 days and median costs were $12345 USD. Nearly 90% of patients were discharged home, and <1% died. Outcomes were similar across all empiric treatments received.

Conclusions

Overuse of antipseudomonal β-lactams and fluoroquinolones was commonplace among lower-risk CA IAI patients. These findings can serve as the basis for an antimicrobial stewardship initiative in hospitals aspiring to reduce the use of broad-spectrum antibiotics.

Comparison of Raja Isteri Pengiran Anak Saleha Appendicitis and modified Alvarado scoring systems in the diagnosis of acute appendicitis

BACKGROUND

The diagnosis of acute appendicitis (AA) is mainly dependent on clinical evaluation. There are several scoring systems developed for an accurate and early diagnosis of AA. Modified Alvarado score is one of the most common systems. The Raja Isteri Pengiran Anak Saleha Appendicitis (RIPASA) scoring system was developed in 2010. The aim of this study is to evaluate and compare the accuracy of modified Alvarado and RIPASA scoring systems for the diagnosis of AA.

METHODS

A total of 100 cases with the clinical diagnosis of AA were included in the study. All the cases were treated surgically. For all cases, modified Alvarado and RIPASA scores were calculated and recorded. According to the calculated cut-off values, sensitivity, specificity, negative and positive predictive values and total accuracy were calculated for each scoring systems.

RESULTS

According to the receiver operating characteristic curve. the optimal score of modified Alvarado score for AA was found to be 5.5 with a sensitivity of 88% and specificity of 69%. According to the receiver operating characteristic curve, the optimal score of RIPASA score for AA was found to be 8.75 with a sensitivity of 94% and specificity of 88%. With the cut-off value of 8.75, total accuracy of RIPASA scoring was found to be 85.2%. Although there is no significant difference in negative appendicectomy rate, both sensitivity and the specificity of the RIPASA were found to be significantly higher than the modified Alvarado.

CONCLUSION

According to the current study, RIPASA scoring system was found to be superior to modified Alvarado in the prediction of cases with AA.

Contemporary Microbiology and Antimicrobial Treatment of Complicated Appendicitis: The Value of a Short-term Study

BACKGROUND

Antimicrobial stewardship interventions to curtail the use of third-generation cephalosporins and antipseudomonal penicillins for the treatment of complicated appendicitis in children are challenging given the tendency to treat complicated disease with broad-spectrum antimicrobials. Reasons for this are unclear, but there is a paucity of contemporary microbiologic data associated with the child presenting with either acute perforated or gangrenous appendicitis. This study aimed to justify the appropriateness of an empiric regimen consisting of ampicillin, tobramycin/gentamicin plus metronidazole and to analyze duration of postoperative therapy.

METHODS

We conducted a retrospective cohort study from February 1, 2017, to October 31, 2018, in children who underwent appendectomy or interventional radiologic drainage for primary complicated appendicitis. The primary outcome was the proportion of patients who had a pathogen isolated from peritoneal fluid culture that was not susceptible to the recommended empiric therapy. The secondary outcomes were the total duration of antimicrobial therapy and the proportion of patients with a postoperative infectious complication within 30 days after intervention.

RESULTS

Of 425 children with primary acute appendicitis, 158 (37%) had complicated appendicitis at presentation. Culture was performed in 53 (40%) of the 133 who underwent a surgical or interventional radiologic intervention. The group with peritoneal cultures was more likely to present with longer symptom duration before admission [3 (interquartile range, 2-5) vs 2 (interquartile range, 1-2) days; P < 0.001] and with purulent peritonitis [47% (25/53) vs 13% (10/80); P < 0.001]. The most common pathogens isolated were anaerobes (81%), Escherichia coli (74%) and Streptococcus anginosus group (62%). Only 4% of isolated bacteria were resistant to empiric therapy. Postoperative infectious complications were documented in 23 (17%) patients and were not associated with the presence of a resistant pathogen or the choice of antimicrobial agents but with more severe disease and higher C-reactive protein values (303 vs 83 mg/L; P=0.03) at presentation.

CONCLUSIONS

In a cohort of previously healthy children presenting with complicated appendicitis requiring surgical drainage, the most common bacteria from peritoneal cultures continue to be S. anginosus, aminoglycoside-susceptible Gram-negative bacilli and anaerobes. In an attempt to reduce extended-spectrum cephalosporin use, these data were useful in supporting the use of metronidazole with ampicillin and an aminoglycoside, rather than third-generation cephalosporins.

Nationwide observational study of mortality from complicated intra-abdominal infections and the role of bacterial cultures

BACKGROUND

The benefit of taking intra-abdominal cultures during source control procedures in patients with complicated intra-abdominal infection (CIAI) is unknown. The aim of this study was to evaluate whether intra-abdominal cultures reduce the mortality rate of CIAI.

METHODS

The Japanese Diagnosis Procedure Combination database was used to identify adult patients with CIAI who had undergone source control procedures on the first day of admission to hospital between April 2014 and March 2016. In-hospital mortality was compared between patients who did and those who did not have intra-abdominal cultures taken. A generalized linear mixed-effect logistic regression model and a random intercept per hospital were used to adjust for baseline confounders and institutional differences. Subgroup analyses were also performed according to disease cause, site of onset and severity of CIAI.

RESULTS

Intra-abdominal cultures were taken from 16 303 of 41 495 included patients. Multivariable logistic regression analysis showed that patients with intra-abdominal cultures had a significantly lower mortality than those without (odds ratio 0·85, 95 per cent c.i. 0·77 to 0·95). Subgroup analyses revealed statistically significant differences in mortality between patients with and without cultures among those with lower intestinal perforation, biliary tract infection/perforation, healthcare-associated CIAI and high-risk community-acquired CIAI.

CONCLUSIONS

Intra-abdominal cultures obtained during source control procedures may reduce in-hospital mortality, especially in patients with lower intestinal perforation, biliary tract infection/perforation, or healthcare-associated or high-risk community-acquired CIAI.

Intraoperative cultures during appendectomy in children are poor predictors of pathogens and resistance patterns in cultures from postoperative abscesses

BACKGROUND

Intraoperative cultures are commonly sent in complicated appendicitis. Culture-guided antibiotics used to prevent postoperative infectious complications are debated. In this study, we describe the microbial overlap between intraoperative and abscess cultures, and antibiotic resistance patterns.

METHOD

A local register of a children's hospital treating children 0-15 years old with appendicitis between 2006 and 2013 was used to find cases with intraoperative cultures, and cultures from drained or aspirated postoperative intraabdominal abscesses. Culture results, administered antibiotics, their nominal coverage of the identified microorganisms, and rationales given for changes in antibiotic regimens were collected from electronic medical records.

RESULTS

In 25 of 35 patients who met inclusion criteria, there was no overlap between the intraoperative and abscess cultures. In 33 of 35 patients, all identified intraoperative organisms were covered with postoperative antibiotics. In 14 patients, organisms in the abscess culture were not covered by administered antibiotics. Enterococci not found in the intraoperative culture were found in 12 of 35 abscesses. We found no difference in the antibiotic coverage between rationales given for antibiotic changes.

CONCLUSION

The overlap between intraoperative cultures and cultures from subsequent abscesses was small. Lack of antibiotic coverage of intraoperative cultures was not an important factor in abscess formation.

Microbiologic Analysis of Complicated and Uncomplicated Acute Appendicitis

BACKGROUND

Microbiologic studies suggest that complicated (CAA) and uncomplicated (UAA) acute appendicitis are different entities. Routine peritoneal fluid cultures continue to be controversially related to a low positive rate, found mainly in UAA; to isolation of typical micro-organisms with expected susceptibilities; and to a community-acquired intra-abdominal infection. The aim of this study was to describe microbiologic isolates in CAA and UAA and the usefulness of peritoneal fluid cultures to determine the susceptibilities to our antibiotic therapy guidelines.

METHODS

This study was a retrospective review of a prospective database collected at University San Juan Hospital (Spain) between June 2014 and June 2017. Complicated acute appendicitis was defined as gangrenous or perforated, whereas UAA was defined as phegmonous or suppurative. Our antibiotic recommendations are amoxicillin-clavulanic acid and in patients with β-lactam allergies, metronidazole plus aztreonam, and an aminoglycoside (gentamicin or tobramycin). Microbiologic cultures were performed in 264 patients, 157 with a CAA and 107 with a UAA.

RESULTS

The positive culture rate was significantly higher in CAA (59%) than in UAA (24.3%). Gram-positive cocci (51.6% CAA; 23.1% UAA), including Streptococcus constellatus (29% CAA; 3.8% UAA), and anaerobes (67.7% CAA; 42.3% UAA) were significantly more common in CAA. The rates of antibiotic resistance were amoxicillin-clavulanic acid 14% (17.2% CAA; 3.8% UAA), gentamicin or tobramycin 8.4% (9.7% CAA; 3.8% UAA), ciprofloxacin 5.9% (6.5% CAA; 3.8% UAA), and ertapenem 10.9% (14% CAA; 0 UAA).

CONCLUSIONS

The culture-positive rate was higher in CAA, with different isolates and susceptibilities than in UAA, identifying a higher frequency of gram-positive cocci (including S. constellatus) and anaerobes. We recommend obtaining peritoneal fluid cultures in CAA, which frequently will lead to a change in the antimicrobial drug therapy guidelines, creating specific recommendations in AA.

Bacterial culture and antibiotic susceptibility in patients with acute appendicitis

PURPOSE

Essential treatment of acute appendicitis is surgical resection with the use of appropriate antibiotics. In order to effectively treat acute appendicitis, it is important to identify the microorganism of acute appendicitis and evaluate the effective antibiotics.

METHODS

A total of 694 patients who underwent appendectomy for acute appendicitis and had positive microbial result between 2006 and 2015 were recruited. For microbial assessment, luminal contents of the appendix were swabbed after appendectomy. In patients with periappendiceal abscess, the specimens were obtained from abscess fluid. The patient characteristics, operative data, use of antibiotics, the results of microbiology, and postoperative morbidities including surgical site infection (SSI) were retrospectively reviewed.

RESULTS

The mean age was 38.2 (± 19.8) years, and 422 patients (60.8%) were male. Most of the operations were performed by conventional laparoscopy (83.1%), followed by single-port laparoscopy (11.8%). The most common microorganism was Escherichia coli (64.6%), which was susceptible to amoxicillin/clavulanate, ciprofloxacin, most cephalosporins, piperacillin/tazobactam, and imipenem. The second most common microorganism was Pseudomonas aeruginosa (16.4%), which was resistant to amoxicillin/clavulanate and cefotaxime. The rate of postoperative morbidity was 8.6%, and the most common type was superficial SSI (6.2%), followed by ileus (1.2%), gastroenteritis (0.7%), and organ/space SSI (0.3%). P. aeruginosa (odds ratio = 2.128, 95% confidence interval 1.077-4.206, P = 0.030) was the only significant microorganism associated with SSI according to multivariate analysis adjusting for other clinical factors.

CONCLUSIONS

In perforated appendicitis, the use of empirical antibiotics seems to be safe. In some cases of Pseudomonas infection, adequate antibiotics should be considered.

Streptococcus anginosus is associated with postoperative intraabdominal collections in appendicitis

AIM OF STUDY

Streptococcus anginosus group (SA) (formerly Streptococcus milleri) are pathogens recognised to have a high risk of postoperative collection in appendicitis, although little data exist specifically in children. We performed a retrospective review of all microbiological data from appendicectomies to assess whether there was an association in children.

METHODS

A retrospective case note review of patients admitted to a paediatric tertiary centre coded for appendicitis from January 2015 to October 2016 was completed. Initial length of stay (LOS), cumulative hospital days, histology, microbiology, and radiology reports were recorded. The postoperative antibiotic regimen was based on surgeon's choice and not standardised.

MAIN RESULTS

231 children were identified, and 18 were excluded. In the remainder, 169 (78.9%) had positive microbiology cultures, and of these 45 were positive for SA (26.6%). There was no significant variation in monthly incidence (P=0.58). Patients with SA+ve cultures were associated with complicated appendicitis on histology (P=0.01), longer LOS and cumulative hospital days (P=0.001), and increased likelihood of developing postoperative collections (P=0.001). The relative risk of developing a postoperative collection with SA+ve cultures was 2.40. There was no difference in time to presentation, histology, or intervention between SA and non-SA patients who developed collections. All SA cultures were sensitive to penicillin and erythromycin.

CONCLUSION

SA cultured from intraoperative serial swabs is associated with an increased risk of developing postoperative collection (2.40). Using this information with standardisation of antimicrobial management may reduce the rate of postoperative complications in paediatric appendicitis.

LEVEL OF EVIDENCE

Level II prognosis study.

Which One is Better? Comparison of the Acute Inflammatory Response, Raja Isteri Pengiran Anak Saleha Appendicitis and Alvarado Scoring Systems

Purpose

Acute appendicitis (AA) is one of the most common causes of an acute abdomen. The accuracies of the Alvarado and the acute inflammatory response (AIR) scores in the diagnosis of appendicitis is very low in Asian populations, so a new scoring system, the Raja Isteri Pengiran Anak Saleha Appendicitis (RIPASA) system, was designed recently. We applied and compared the Alvarado, AIR, and RIPASA scores in the diagnoses of appendicitis in the Iranian population.

Methods

We prospectively compared the RIPASA, Alvarado, and AIR systems by applying them to 100 patients. All the scores were calculated for patients who presented with right quadrant pain. Appendectomies were performed; then, the postoperative pathology reports were correlated with the scores. Scores of 8, 7, and 5 or more are optimal cutoffs for the RIPASA, Alvarado, and AIR scoring systems, respectively. The sensitivities, specificities, positive predictive values, negative predictive values (NPVs), positive and negative likelihood ratios (LRs) for the 3 systems were determined.

Results

The sensitivity and the specificity of the RIPASA score were 93.18% and 91.67%, respectively. The sensitivities of the Alvarado and the AIR scores were both 78.41%. The specificities of the Alvarado and the AIR scores were 100% and 91.67%, respectively. The RIPASA score correctly classified 93% of all patients confirmed with histological AA compared with 78.41% for the Alvarado and the AIR scores.

Conclusion

The RIPASA scoring system had more sensitivity, better NPV, a positive LR, and a less negative LR for the Iranian population whereas the Alvarado scoring system was more specific.

Bad bacteria in acute appendicitis: rare but relevant

PURPOSE

Bacterial infections are a factor for morbidity in patients with acute appendicitis (AA). The spreading of multidrug-resistant (MDR) bacteria is a significant problem in surgery, and the most relevant MDR pathogens are summarized as Enterobacteriaceae, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterococci (ESKAPE) bacteria. Data regarding the species and distribution of bacteria in AA are available, but information about the resistances and their relevance is deficient.

METHODS

In this retrospective study, we analyzed microbiological swabs of patients with AA. The outcome parameters of patients after laparoscopic appendectomy were analyzed against microbiological results, including antibiotic resistance testing. Positive swabs were compared with bacteria cultivated after alternative abdominal emergency surgery (AES).

RESULTS

In total, 584 patients with AA were included and had a mean age of 35.5 years. In 216 patients (36.9%), a swab was taken, and in 128 (59.3%) swabs, bacteria could be cultivated. The most frequent organisms were Escherichia coli, Bacteroides species, and Pseudomonas. In 9.4% of the positive AA swabs, MDR germs were cultivated, and all of them were ESKAPE pathogens. Patients with MDR bacteria in AA suffered more infectious complications (p = 0.006) and needed longer hospitalizations (p < 0.009). In AES, aside from appendicitis, a different spectrum containing more MDR bacteria was cultivated (5.9 vs. 20.9%; p < 0.0001).

CONCLUSIONS

Although they occur less frequently in appendectomy compared to emergency surgeries for other abdominal diseases, MDR bacteria are traceable in this common disease and contribute to additional morbidity.

The management of intra-abdominal infections from a global perspective: 2017 WSES guidelines for management of intra-abdominal infections

Intra-abdominal infections (IAIs) are common surgical emergencies and have been reported as major contributors to non-trauma deaths in the emergency departments worldwide. The cornerstones of effective treatment of IAIs are early recognition, adequate source control, and appropriate antimicrobial therapy. Prompt resuscitation of patients with ongoing sepsis is of utmost important. In hospitals worldwide, non-acceptance of, or lack of access to, accessible evidence-based practices and guidelines result in overall poorer outcome of patients suffering IAIs. The aim of this paper is to promote global standards of care in IAIs and update the 2013 WSES guidelines for management of intra-abdominal infections.

The Surgical Infection Society Revised Guidelines on the Management of Intra-Abdominal Infection

BACKGROUND

Previous evidence-based guidelines on the management of intra-abdominal infection (IAI) were published by the Surgical Infection Society (SIS) in 1992, 2002, and 2010. At the time the most recent guideline was released, the plan was to update the guideline every five years to ensure the timeliness and appropriateness of the recommendations.

METHODS

Based on the previous guidelines, the task force outlined a number of topics related to the treatment of patients with IAI and then developed key questions on these various topics. All questions were approached using general and specific literature searches, focusing on articles and other information published since 2008. These publications and additional materials published before 2008 were reviewed by the task force as a whole or by individual subgroups as to relevance to individual questions. Recommendations were developed by a process of iterative consensus, with all task force members voting to accept or reject each recommendation. Grading was based on the GRADE (Grades of Recommendation Assessment, Development, and Evaluation) system; the quality of the evidence was graded as high, moderate, or weak, and the strength of the recommendation was graded as strong or weak. Review of the document was performed by members of the SIS who were not on the task force. After responses were made to all critiques, the document was approved as an official guideline of the SIS by the Executive Council.

RESULTS

This guideline summarizes the current recommendations developed by the task force on the treatment of patients who have IAI. Evidence-based recommendations have been made regarding risk assessment in individual patients; source control; the timing, selection, and duration of antimicrobial therapy; and suggested approaches to patients who fail initial therapy. Additional recommendations related to the treatment of pediatric patients with IAI have been included.

SUMMARY

The current recommendations of the SIS regarding the treatment of patients with IAI are provided in this guideline.

Management of intra-abdominal infections: recommendations by the WSES 2016 consensus conference

This paper reports on the consensus conference on the management of intra-abdominal infections (IAIs) which was held on July 23, 2016, in Dublin, Ireland, as a part of the annual World Society of Emergency Surgery (WSES) meeting. This document covers all aspects of the management of IAIs. The Grading of Recommendations Assessment, Development and Evaluation recommendation is used, and this document represents the executive summary of the consensus conference findings.

Antimicrobials: a global alliance for optimizing their rational use in intra-abdominal infections (AGORA)

Intra-abdominal infections (IAI) are an important cause of morbidity and are frequently associated with poor prognosis, particularly in high-risk patients. The cornerstones in the management of complicated IAIs are timely effective source control with appropriate antimicrobial therapy. Empiric antimicrobial therapy is important in the management of intra-abdominal infections and must be broad enough to cover all likely organisms because inappropriate initial antimicrobial therapy is associated with poor patient outcomes and the development of bacterial resistance. The overuse of antimicrobials is widely accepted as a major driver of some emerging infections (such as C. difficile), the selection of resistant pathogens in individual patients, and for the continued development of antimicrobial resistance globally. The growing emergence of multi-drug resistant organisms and the limited development of new agents available to counteract them have caused an impending crisis with alarming implications, especially with regards to Gram-negative bacteria. An international task force from 79 different countries has joined this project by sharing a document on the rational use of antimicrobials for patients with IAIs. The project has been termed AGORA (Antimicrobials: A Global Alliance for Optimizing their Rational Use in Intra-Abdominal Infections). The authors hope that AGORA, involving many of the world's leading experts, can actively raise awareness in health workers and can improve prescribing behavior in treating IAIs.

[Comparison of two protocols of prophylactic antibiotic therapy in childhood appendectomy]

OBJECTIVE

Antibiotic administration during acute appendicitis in children continues to be debated. The purpose of this study was to compare efficacy of two prophylactic antibiotic treatment guidelines in acute appendicitis and peritonitis in children.

MATERIEL AND METHODS

The infectious complication rate after appendicectomy was compared during two distinct periods (before/after study). During the first period, the guidelines for antibiotic administration were based on ticarcillin-clavulanic acid. During the second period, the guidelines were based on amoxicillin-clavulanic acid for non-perforated appendicitis or appendicitis with localized peritonitis, and clavulanic acid was reserved for general peritonitis. All children younger than 16 years of age who underwent appendicectomy during the periods studied were included. Data were retrospectively collected from surgical and anesthetics charts.

RESULTS

Ninety-five children during the first period and 238 during the second were included. In the children with non-perforated appendicitis, no postoperative infectious complication occurred in 74 children during the first period versus two out of 153 (1%) during the second period. In cases of perforated appendicitis, postoperative infectious complications occurred two cases (10%) during the first period versus nine (11%) during the second. There were no significant differences between the two periods.

CONCLUSION

In this population, antibiotic administration guidelines based on amoxicillin-clavulanic acid for stages I-III of appendicitis maintained a low rate of postoperative infectious complications and were not associated with a higher postoperative infectious complication rate than guidelines based on ticarcillin-clavulanic acid.

The microbiology of bacterial peritonitis due to appendicitis in children

AIM

The aim of this study was to investigate the microbiology of secondary bacterial peritonitis due to appendicitis and the appropriateness of current antimicrobial practice in one institution.

METHODS

A 14-year retrospective single-centre study of 69 consecutive paediatric patients (age 1-14 years) with appendicitis-related peritonitis and positive peritoneal specimen cultures was conducted. Post-operative outcomes, microbiology and antibiotic susceptibility of peritoneal isolates were analysed in all patients.

RESULTS

Escherichia coli was identified in 56/69 (81 %) peritoneal specimens; four isolates were resistant to amoxicillin-clavulanate, and one other isolate was resistant to gentamicin. Anaerobes were identified in 37/69 (54 %) peritoneal specimens; two anaerobic isolates were resistant to amoxicillin-clavulanate and one isolate was resistant to metronidazole. Pseudomonas aeruginosa was identified in 4/69 (6 %) peritoneal specimens, and all were susceptible to gentamicin. Streptococcal species (two Group F streptococci and three β-haemolytic streptococci) were identified in 5/69 (7 %) specimens, and all were susceptible to amoxicillin-clavulanate. Combination therapy involving amoxicillin-clavulanate and aminoglycoside is appropriate empirical treatment in 68/69 (99 %) patients. Addition of metronidazole to this regime would provide 100 % initial empirical coverage. Inadequate initial empiric antibiotic treatment and the presence of amoxicillin-clavulanate resistant E. coli were independent predictors of the post-operative infectious complications observed in 14/69 (20 %) patients.

CONCLUSION

E. coli and mixed anaerobes are the predominant organisms identified in secondary peritonitis from appendicitis in children. Inadequate initial empirical antibiotic and amoxicillin-clavulanate resistant E. coli may contribute to increased post-operative infectious complications. This study provides evidence-based information on choice of combination therapy for paediatric appendicitis-related bacterial peritonitis.

2013 WSES guidelines for management of intra-abdominal infections

Despite advances in diagnosis, surgery, and antimicrobial therapy, mortality rates associated with complicated intra-abdominal infections remain exceedingly high.The 2013 update of the World Society of Emergency Surgery (WSES) guidelines for the management of intra-abdominal infections contains evidence-based recommendations for management of patients with intra-abdominal infections.

Bacterial studies of complicated appendicitis over a 20-year period and their impact on empirical antibiotic treatment

BACKGROUND

Multiresistant bacterial strains tend to develop, especially enterobacteriacae, in intraabdominal infections. The aim of this study was to characterize the evolution of the bacterial biota in complicated appendicitis in children over the past 20 years and their acquired resistance rates to antibiotics.

MATERIALS AND METHODS

All pediatric patients admitted in the emergency unit for complicated appendicitis were retrospectively reviewed during 3 periods: 1989 to 1991, 1999 to 2000, and 2009 to 2010. Results of peritoneal swabs were analyzed regarding bacterial species and resistance to antibiotics. Statistical significance was set at P < .05.

RESULTS

Thirty-four, 48, and 85 patients from the 3 periods, respectively, were included, with 1 to 6 bacterial strains found in each peritoneal sample. During the first period, 80% of the biota was composed of enterobacteriacae and anaerobes and then decreased to 65%, whereas streptococci levels increased from 0 to 22%. Pansusceptibility rates remained stable (17%, 16.8%, and 15.6% for the 3 periods, respectively). Piperacillin, vancomycin, ticarcillin-clavulanic acid, and fluoroquinolones were associated with increased resistance rates, unlike antibiotic associations currently used as postoperative treatments.

CONCLUSION

No significant increase in resistance rates of bacteriacae in complicated appendicitis in children was found over the last 20 years. Empirical antibiotherapy protocols currently recommended remain efficient on this particular biota.

[Microbiological diagnosis of intra-abdominal infections]

Intra-abdominal infections represent a large and wide group of diseases which include intra- and retro-peritoneal infections. Some of them could be defined as uncomplicated, where the infectious process is limited to the organ or tissue of origin (appendicitis, diverticulitis, cholecystitis…). Complications occur when the infection spreads to the peritoneum, triggering localised peritonitis and abdominal abscesses. Most intra-abdominal infections are due to perforation or inflammation of the intestinal wall. The microorganisms that cause these infections come from the gastrointestinal flora, and therefore produce polymicrobial infections mixed with a predominance of anaerobic bacteria. Microbiological diagnosis is essential to determine the aetiology and the susceptibility of antimicrobial agents of the microorganism involved, especially in nosocomial infections or in community infections in predisposed patients due to increasing bacterial resistance to antimicrobial agents, multidrug resistance and fungal involvement. Despite the advances in microbiological diagnosis, in the case of intra-abdominal infections it still remains direct, being based on stains and cultures, the most notable progress is the introduction of mass spectrometry (MALDI-TOF) for the rapid identification of the pathogens involved. This review will provide recommendations on the collection, transport and microbiological processing of clinical specimens. Comments on the pathogenesis, clinical and microbiological diagnosis of peritonitis primary, secondary, tertiary and peritonitis (and other infections) associated with peritoneal dialysis, intra-abdominal abscesses (intraperitoneal, retroperitoneal and visceral), biliary tract infections, appendicitis and diverticulitis are also presented.