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

Perforated Appendicitis in Children: Management, Microbiology, and Antibiotic Stewardship

Although appendicitis has been described for more than 300 years, its optimal management remains a topic of active investigation. Acute appendicitis is the most common cause of peritonitis in children, and rates of perforated appendicitis are much higher in children than in adults. Increased risk for perforated appendicitis in children is related to a delay in diagnosis due to age, size, access to care, and more. Surgical options include immediate appendectomy versus nonoperative management with intravenous antibiotics ± a drainage procedure, with a subsequent interval appendectomy. Microbiota of perforated appendicitis in children most often includes Escherichia coli, Bacteroides fragilis, Streptococcus, and more. Even though the most common organisms are known, there is a large variety of practice when it comes to postoperative antibiotic management in these patients. Studies discuss the benefits of mono- versus dual or triple therapy without a particular consensus regarding what to use. This is reflected across differing practices at various institutions. In this review, we aim to explore the implications of perforated appendicitis in pediatrics, common organisms seen, antibiotic regimen coverage, and the implications of variations of practice. Resistance to commonly used broad-spectrum antibiotics is evolving, therefore minimization of care variability is needed for improved patient outcomes and proper antibiotic stewardship.

Intraoperative bacterial cultures fail to reliably predict the bacterial spectrum encountered during infectious complications after appendicitis

Acute appendicitis is a common surgical emergency. Complicated appendicitis usually warrants perioperative antibiotic treatment in order to prevent infectious complications. Whether routine microbiological testing benefits the individual patient is a topic of debate. The goal of our study was to assess perioperative antibiotic prescriptions as well as the benefit of microbiological testing during the appendectomy as a predictor for bacteria encountered in infectious complications. This is a retrospective analysis of 1218 consecutive patients that underwent appendectomy at a tertiary referral center between 2014 and 2021. The patient charts were systematically analyzed regarding intraoperative outcome, microbiologic results, and postoperative infectious complications. 1218 patients were included in this study of which 768 were uncomplicated appendicitis (UA) and 450 were complicated appendicitis (CA). Microbiological testing was performed in 39.2% of UA cases (33.6% of which grew bacteria) compared to 74.9% of CA cases (78.6% positive cultures). The strongest individual predictors for SSI were gangrenous and perforated appendicitis. A total of 58 surgical-site infections developed, of which 49 were intra-abdominal fluid collections or abscesses. Thirty-two patients had revision surgery or CT-guided drainage for SSI. In the cases where microbiological testing was done both during the appendectomy and the SSI, 13/18 showed different bacteria on culture testing. The infectious outcome was favorable in 98.3%. While microbiological testing offers insights into resistance patterns, it is of little benefit for the individual patient, given the low predictive value for bacteria found during SSI. Achieving source control combined with empiric antibiotic coverage leads to favorable outcomes independent of culture results.

Association of the Bacteria of the Vermiform Appendix and the Peritoneal Cavity with Complicated Acute Appendicitis in Children

BACKGROUND

Primary infection has been questioned as the pathogenetic cause of acute appendicitis. We attempted to identify the bacteria involved and to investigate if their species, types, or combinations affected the severity of acute appendicitis in children.

METHODS

Samples from both the appendiceal lumen and the peritoneal cavity of 72 children who underwent appendectomy were collected to perform bacterial culture analysis. The outcomes were studied to identify if and how they were associated with the severity of the disease. Regression analysis was performed to identify any risk factors associated with complicated appendicitis.

RESULTS

Escherichia coli, Pseudomonas aeruginosa, and Streptococcus species were the most common pathogens found in the study population. The same microorganisms, either combined or separate, were the most common in the appendiceal lumen and the peritoneal cavity of patients with complicated appendicitis. Gram-negative bacteria and polymicrobial cultures in the peritoneal fluid and in the appendiceal lumen were associated with complicated appendicitis. Polymicrobial cultures in the peritoneal cavity presented a four times higher risk of complicated appendicitis.

CONCLUSIONS

Polymicrobial presentation and Gram-negative bacteria are associated with complicated appendicitis. Antibiotic regimens should target the combinations of the most frequently identified pathogens, speculating the value of early antipseudomonal intervention.

Optimal First-Line Antibiotic Treatment for Pediatric Complicated Appendicitis Based on Peritoneal Fluid Culture

PURPOSE

Consensus is lacking regarding the optimal antibiotic treatment for pediatric complicated appendicitis. This study determined the optimal first-line antibiotic treatment for pediatric patients with complicated appendicitis based on peritoneal fluid cultures.

METHODS

This retrospective study examined the cases of pediatric patients who underwent appendectomy for complicated appendicitis at our institution between 2013 and 2019. Peritoneal fluid specimens obtained during appendectomy were cultured for the presence of bacteria.

RESULTS

Eighty-six pediatric patients were diagnosed with complicated appendicitis. Of them, bacteria were identified in 54 peritoneal fluid samples. The major identified bacteria were Escherichia coli (n=36 [66.7%]), Bacteroides fragilis (n=28 [51.9%]), α-Streptococcus (n=25 [46.3%]), Pseudomonas aeruginosa (n=10 [18.5%]), Enterococcus avium (n=9 [16.7%]), γ-Streptococcus (n=9 [16.7%]), and Klebsiella oxytoca (n=6 [11.1%]). An antibiotic susceptibility analysis showed E. coli was inhibited by sulbactam/ampicillin in 43.8% of cases versus cefmetazole in 100% of cases. Tazobactam/piperacillin and meropenem inhibited the growth of 96.9-100% of the major identified bacteria. E. coli (100% vs. 84.6%) and P. aeruginosa (100% vs. 80.0%) were more susceptible to amikacin than gentamicin.

CONCLUSION

Tazobactam/piperacillin or meropenem is a reasonable first-line antibiotic treatment for pediatric complicated appendicitis. In the case of aminoglycoside use, amikacin is recommended.

ANTIBIOTICS FOR APPENDICECTOMY IN CHILDREN AND ADOLESCENTS DURING THE PERIOPERATIVE PERIOD: AN INTEGRATIVE REVIEW

ABSTRACT Objective: To analyze the preoperative use of antibiotics in children and adolescents requiring appendectomy. Data source: Integrative review was performed in the MEDLINE, Latin American and Caribbean Health Sciences (LILACS) and Cochrane databases and the PubMed portal, with no time limit. The keywords used were: appendicitis, child, adolescent and antibacterial with Boolean AND. The articles included were published in Portuguese, English or Spanish and whose participants were under 18 years of age. Review articles and guidelines were excluded. The studies were classified according to their level of evidence and 24 papers were selected. Data collection and analysis: Seven randomized clinical trial studies (level of evidence II), eight cohorts (level III), seven retrospective observational studies (level V) and two historical documentary analysis (level IV) were selected. The studies addressed antibiotics used in acute appendicitis in both uncomplicated and complicated cases. Antibiotics initiated in the preoperative period showed a decrease in the rates of surgical wound infections. First-line (empiric) regimens were tested for sensitivity to microorganisms in peritoneal material cultures, however the results were controversial. Broad-spectrum antibiotics have been suggested in some studies because they have good coverage, but in others they have not been recommended because of the risk of developing bacterial resistance. Shorter administration time and earlier change to the oral route reduced hospitalization time. Conclusions: There are several clinical protocols with different antibiotics. However, there is no standardization concerning the type of antibiotic drug, time of use, or route.

Simplification of first-line antibacterial regimen for complicated appendicitis in children is associated with better adherence to guidelines and reduced use of antibiotics

Acute appendicitis in children requires early surgery and short-course antibiotics active against Enterobacteriaceae and anaerobes. Although an aminoglycoside-containing three-drug regimen has been used successfully for decades, simpler regimens with similar efficacy are increasingly used. This study evaluated the impact of a switch from the combination of cefotaxime, metronidazole and gentamicin (regimen 1) to piperacillin/tazobactam (regimen 2) as first-line regimen for complicated acute appendicitis in children. In total, 171 children were enrolled [median (IQR) age, 10 (6-13) years], treated with regimen 1 (n = 80) or regimen 2 (n = 91) following surgery for complicated acute appendicitis. The two groups were comparable except for surgical approach (through laparoscopy in 46% vs. 88% for regimens 1 and 2, respectively; P < 0.001). Post-operative complications and duration of hospital stay were similar. Deviations from antibacterial treatment protocol decreased from 36% (29/80) to 14% (13/91) (P < 0.001), with a dramatic reduction in antibacterial treatment duration from median (IQR) of 15 (12-16) days to 5 (5-8) days (P < 0.001). Post-operative intra-abdominal abscess developed in 32 children (18.7%). Female sex (OR = 2.76, 95% CI 1.18-6.48; P = 0.02) and sepsis/septic shock on admission (OR = 4.72, 95% CI 1.12-19.97; P = 0.035) were independently associated with post-operative intra-abdominal abscess, but not antibacterial regimen. This study shows that simplification of first-line antibacterial regimen for complicated appendicitis in children was associated with reduced protocol deviation, reduced duration of antibiotics, and similar outcomes (post-operative complications and duration of hospital stay).

Initial non-operative management of uncomplicated appendicitis in children: a protocol for a multicentre randomised controlled trial (APAC trial)

INTRODUCTION

Based on epidemiological, immunological and pathology data, the idea that appendicitis is not necessarily a progressive disease is gaining ground. Two types are distinguished: simple and complicated appendicitis. Non-operative treatment (NOT) of children with simple appendicitis has been investigated in several small studies. So far, it is deemed safe. However, its effectiveness and effect on quality of life (QoL) have yet to be established in an adequately powered randomised trial. In this article, we provide the study protocol for the APAC (Antibiotics versus Primary Appendectomy in Children) trial.

METHODS AND ANALYSIS

This multicentre, non-inferiority, randomised controlled trial randomises children aged 7-17 years with imaging-confirmed simple appendicitis between appendectomy and NOT. Patients are recruited in 15 hospitals. The intended sample size, based on the primary outcome, rate of complications and a non-inferiority margin of 5%, is 334 patients.NOT consists of intravenous antibiotics for 48-72 hours, daily blood tests and ultrasound follow-up. If the patient meets the predefined discharge criteria, antibiotic treatment is continued orally at home. Primary outcome is the rate of complications at 1-year follow-up. An independent adjudication committee will assess all complications and their relation to the allocated treatment. Secondary outcomes include, but are not limited to, delayed appendectomies, QoL, pain and (in)direct costs.The primary outcome will be analysed both according to the intention-to-treat principle and the per-protocol principle, and is presented with a one-sided 97.5% CI. We will use multiple logistic and linear regression for binary and continuous outcomes, respectively, to adjust for stratification factors.

ETHICS AND DISSEMINATION

The protocol has been approved by the Medical Ethics Review Committee of the Academic Medical Center, Amsterdam. Data monitoring is performed by an independent institute and a Data Safety Monitoring Board has been assigned. Results will be presented in peer-reviewed academic journals and at (international) conferences.

TRIAL REGISTRATION NUMBER

NCT02848820; NTR5977; Pre-results.

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.

Epidemiology and Antimicrobial Susceptibility of Gram-Negative Pathogens Causing Intra-abdominal Infections in Pediatric Patients in Europe-SMART 2011-2014

BACKGROUND

The most common type of intra-abdominal infection (IAI) is appendicitis, which occurs most frequently in children and young adults. Yet, few studies on the microbiology of pediatric IAI are available, which is problematic because antimicrobial therapy for IAI usually needs to be initiated before microbiological culture results are available. With this study, we aimed to assess whether resistance patterns in pediatric IAI in Europe that would help clinicians select empiric therapy can be identified.

METHODS

Gram-negative pathogens (n = 1259) were collected from pediatric patients as part of the Study for Monitoring Antimicrobial Resistance Trends (SMART) in 16 European countries from 2011 to 2014. Minimal inhibitory concentrations (MICs) and extended-spectrum β-lactamase (ESBL) phenotype were determined by broth microdilution according to Clinical and Laboratory Standards Institute guidelines, and susceptibility was interpreted according to European Committee on Antimicrobial Susceptibility Testing guidelines. An IAI was defined as hospital- or community-associated if cultured ≥48 or <48 hours after admission, respectively.

RESULTS

Overall, only imipenem and amikacin exceeded 90% susceptibility when all Gram-negative pathogens were combined, and ertapenem, cefepime, ceftazidime, piperacillin-tazobactam, and levofloxacin reached at least 85%. However, resistance, ESBL-positive, and multidrug-resistance (MDR) rates were substantially higher in isolates from patients with hospital-associated IAI than from those with community-associated IAI (eg, 14.1% vs 5.1% MDR isolates, respectively, among all Gram-negative pathogens), higher in isolates from intensive care units than in those from general wards, and higher in isolates from infants than in those from children ≥1 year of age. In addition, MDR rates varied markedly within Europe.

CONCLUSIONS

These results indicate that empiric therapy of pediatric IAI in Europe should reflect not only regional and local resistance patterns but also higher resistance rates in hospital-associated infections, intensive care units, and infants.

Guidelines for management of intra-abdominal infections

Intra-abdominal infections are one of the most common gastrointestinal emergencies and a leading cause of septic shock. A consensus conference on the management of community-acquired peritonitis was published in 2000. A new consensus as well as new guidelines for less common situations such as peritonitis in paediatrics and healthcare-associated infections had become necessary. The objectives of these Clinical Practice Guidelines (CPGs) were therefore to define the medical and surgical management of community-acquired intra-abdominal infections, define the specificities of intra-abdominal infections in children and describe the management of healthcare-associated infections. The literature review was divided into six main themes: diagnostic approach, infection source control, microbiological data, paediatric specificities, medical treatment of peritonitis, and management of complications. The GRADE(®) methodology was applied to determine the level of evidence and the strength of recommendations. After summarising the work of the experts and application of the GRADE(®) method, 62 recommendations were formally defined by the organisation committee. Recommendations were then submitted to and amended by a review committee. After 2 rounds of Delphi scoring and various amendments, a strong agreement was obtained for 44 (100%) recommendations. The CPGs for peritonitis are therefore based on a consensus between the various disciplines involved in the management of these patients concerning a number of themes such as: diagnostic strategy and the place of imaging; time to management; the place of microbiological specimens; targets of empirical anti-infective therapy; duration of anti-infective therapy. The CPGs also specified the value and the place of certain practices such as: the place of laparoscopy; the indications for image-guided percutaneous drainage; indications for the treatment of enterococci and fungi. The CPGs also confirmed the futility of certain practices such as: the use of diagnostic biomarkers; systematic relaparotomies; prolonged anti-infective therapy, especially in children.

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.