Bacteriologic epidemiology and empirical treatment of pediatric complicated appendicitis

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.

Microbiome Structure and Mucosal Morphology of Jejunum Appendix and Colon of Rats in Health and Dysbiosis

Gut microbiota contributes to human health. Plenty of studies demonstrate that antibiotics can disrupt gut ecosystem leading to dysbiosis. Little is known about the microbial variation of appendix and its up/downstream intestine after antibiotic treatment. This study aimed to investigate the microbiome and mucosal morphology of jejunum, appendix, and colon of rats in health and dysbiosis. A rodent model of antibiotic-induced dysbiosis was employed. Microscopy was used to observe mucosal morphological changes. 16S rRNA sequencing was performed for identifying bacterial taxa and microbiome structure. The appendices of dysbiosis were found enlarged and inflated with loose contents. Microscopy revealed the impairment of intestinal epithelial cells. High-throughput sequencing showed the Operational Taxonomic Units changed from 361 ± 33, 634 ± 18, 639 ± 19 in the normal jejunum, appendix, colon to 748 ± 98, 230 ± 11, 253 ± 16 in the disordered segments, respectively. In dysbiosis, Bacteroidetes translocated inversely from the colon and appendix (0.26%, 0.23%) to the jejunum (13.87% ± 0.11%); the relative abundance of all intestinal Enterococcaceae increased, while Lactobacillaceae decreased. Several bacterial clusters were found correlated to the normal appendix, whereas nonspecific clusters correlated to the disordered appendix. In conclusion, species richness and evenness reduced in the disordered appendix and colon; similar microbiome patterns were shared between the appendix and colon regardless of dysbiosis; site-specific bacteria were missing in the disordered appendix. Appendix is likely a transit region involving in upper and lower intestinal microflora modulation. The limitation of this study is all the data were derived from rats. We must be cautious about translating the microbiome results from rats to humans.

Using Microbiology Culture in Pediatric Appendicitis to Risk Stratify Patients: A Cohort Study

Background: We sought to investigate the value of intra-operative microbiology samples in pediatric appendicitis. Proposed benefits include tailoring post-operative antimicrobial management, risk-stratifying patients, and reducing post-operative intra-abdominal abscess formation. Patients and Methods: All cases of appendicitis managed with appendicectomy in a single center were collected from January 2015 to August 2020. Intra-operative microbiology samples were taken routinely. Post-operative outcomes were analyzed with reference to culture and sensitivity results. Histologic findings were further categorized as normal, simple, or complex. Results: Six hundred seventy-eight children had appendicectomies, and 608 had both microbiology and histology samples taken. Intra-abdominal fluid collection and subsequent intervention rates were 22% and 9%, respectively. There were more collections in those with a culture positive result (p < 0.001), and those growing each of three recognized organisms, Escherichia coli (p < 0.001), Pseudomonas aeruginosa (p = 0.01), and Streptococcus anginosus group (p < 0.001). Intervention rate was higher in the culture-positive result group (p = 0.002) and the Streptococcus anginosus group (p < 0.001). Conclusions: This study shows an increased risk of developing a collection with the isolation of one of three key organisms (Escherichia coli, Pseudomonas aeruginosa, Streptococcus anginosus group). Sersoal swabs are an effective and practical method of gathering information on organisms. Microbiologic yield was correlated to the severity of appendicitis. Isolation of Streptococcus anginosus increases the incidence of collections to 50%. This is useful to empower surgeons to prognosticate patients' potential outcomes based on both intra-operative, and microbiologic findings, and is useful in counseling patients and managing expectations. A prolonged course of antibiotic agents or higher dose may mitigate this risk.

Differences in isolated bacteria between perforated and non-perforated appendicitis: an analysis of 680 consecutive appendicectomies in a single institution

PURPOSE

Escherichia coli and Bacteroides species are the most frequently detected species in ascites in perforated appendicitis and are generally sensitive to non-empiric cephalosporins like cefazolin or cefmetazole. However, monotherapy with such antibiotics is mostly insufficient for perforated appendicitis. To investigate this issue, this study aimed to compare bacterial floras in ascites culture between perforated and non-perforated appendicitis.

METHODS

Ascites culture results in perforated and non-perforated appendicitis cases were analyzed using a departmental database. The duration of symptoms before surgery, pre-surgical white blood cell count, C-reactive protein value, postsurgical length of stay, length of antibiotic treatment, and the rate of using second-line antibiotics or complications were also compared.

RESULTS

A total of 608 and 72 cases of non-perforated and perforated appendicitis were included. Escherichia coli and Bacteroides species were the dominant bacteria in both conditions. However, the total proportions of Pseudomonas aeruginosa, Streptococcus anginosus group, and Enterococcus group were significantly higher in perforated appendicitis than in non-perforated appendicitis.

CONCLUSION

Pseudomonas aeruginosa, Streptococcus anginosus group, and Enterococcus group have better susceptibility to penicillin-based empiric antibiotics than cephalosporins. The abundance of these bacteria might explain why non-empiric cephalosporins are not effective in perforated appendicitis and the superiority of penicillin-based empiric antibiotics.

Ceftriaxone with Metronidazole versus Piperacillin/Tazobactam in the management of complicated appendicitis in children: Results from a multicenter pediatric NSQIP analysis

BACKGROUND

Narrow-spectrum antibiotics have been found to be equivalent to anti-Pseudomonal agents in preventing organ space infections (OSI) in children with uncomplicated appendicitis. Comparative effectiveness data for children with complicated appendicitis remains limited. This investigation aimed to compare outcomes between the most common narrow-spectrum regimen (ceftriaxone with metronidazole: CM) and anti-Pseudomonal regimen (piperacillin/tazobactam: PT) used perioperatively in children with complicated appendicitis.

METHODS

Multicenter retrospective cohort study using clinical data from the NSQIP-Pediatric Appendectomy Collaborative database merged with antibiotic utilization data from the Pediatric Health Information System database. Mixed-effects multivariate regression was used to compare NSQIP-defined outcomes and resource utilization between treatment groups after adjusting for patient characteristics, disease severity, and clustering of outcomes within hospitals.

RESULTS

654 patients from 14 hospitals were included, of which 37.9% received CM and 62.1% received PT. Following adjustment, patients in both groups had similar rates of OSI (CM: 13.3% vs. PT: 18.0%, OR 0.88 [95%CI 0.38, 2.03]), drainage procedures (CM: 8.9% vs. PT: 14.9%, OR 0.76 [95%CI 0.30, 1.92]), and postoperative imaging (CM: 19.8% vs. PT: 22.5%, OR 1.17 [95%CI 0.65, 2.12]). Treatment groups also had similar rates of 30-day cumulative post-operative length of stay (CM: 6.1 vs. PT: 6.0 days, RR 1.01 [95%CI 0.81, 1.25]) and hospital cost (CM: $19,235 vs. PT: $20,552, RR 0.92 [95%CI 0.69, 1.23]).

CONCLUSIONS

Rates of organ space infection and resource utilization were similar in children with complicated appendicitis treated with ceftriaxone plus metronidazole and piperacillin/tazobactam.

LEVEL OF EVIDENCE

Level III: Treatment study - Retrospective comparative study.

The Gut Microbiota and Inflammatory Factors in Pediatric Appendicitis

Background. The study analyzed gut microflora’s composition and investigated the associations between the associations between gut dysbiosis and inflammatory indicators in pediatric patients with acute appendicitis. Methods. High-throughput sequencing and bioinformatics analysis were used to investigate the composition and diversity of gut microflora in 20 pediatric patients with acute appendicitis and 11 healthy children. Endpoints measured were operational taxonomic units (OTU) of gut microflora. The OTU and its abundance analysis, sample diversity analysis, principal component analysis of samples, differential analysis, and analysis of biomarkers were performed. Results. Overall fecal microbial richness and diversity were similar in patients and controls. Yet richness within the group of Bilophila, Eggerthella, Clostridium, Parvimonas, Megasphaera, Atopobium, Phascolarctobacterium, Adlercreutzia, Barnesiella, Klebsiella, Enterococcus, and Prevotella genera was higher in patients. Adlercreutzia was significantly positively correlated with IL-10, while the three other genera, comprising Klebsiella, Adlercreutzia, and Prevotella, were positively correlated with B cells level. Conclusion. Gut microbiome components are significantly different in pediatric patients with acute appendicitis and healthy children. The differential abundance of some genera is correlated with the production of inflammatory markers in appendicitis.

Amoxycillin/Clavulanic acid monotherapy in complicated paediatric appendicitis: Good enough?

BACKGROUND

Antibiotic choice for complicated appendicitis should be based on both microbiological effectiveness as well as ease of administration and cost especially in lower resourced settings. Data is limited on comparative morbidity outcomes for antibiotics with similar microbiological spectrum of activity. Incidence and morbidity of surgical site infection after appendectomy for complicated appendicitis was assessed after protocol change from triple antibiotic (ampicillin, gentamycin, and metronidazole) regimen to single agent (amoxycillin/clavulanic acid).

METHODS

Surgical site infection (SSI) rate, relook surgery rate and length of hospital stay were retrospectively compared in patients treated for acute appendicitis preceding (2014, 2015; "triple-therapy, TT") and following (2017, 2018; "single agent, SA") antibiotic protocol change.

RESULTS

The rate of complicated appendicitis was similar between groups; 72.6% in TT and 66% in SA (p = 0.239). Significantly, SSI occurred in 22.7% of the SA group compared to 13.3% in TT group (OR 1.920, 95% CI 1.000-3.689, p = 0.048). Use of laparoscopy increased from 31% in TT to 89% in SA, but with subgroup analysis this was not associated with increased SSI (17.3% in open and 20.6% in laparoscopic; OR 0.841, 95% CI 0.409-1.728, p = 0.637). Relook rate (OR 1.444, 95% CI 0.595-3.507, p = 0.093) length of hospital stay (U = 6859, z = -1.163, p = 0.245), and ICU admission (U = 7683, z = 0.634 p = 0.522) were equivocal. Neither group had mortalities.

CONCLUSIONS

Despite increased SSI with SA, overall morbidity relating to ICU admission, relook rate and length of hospital stay was similar in both groups. More prospective research is required to confirm equivalent overall morbidity and that single agent therapy is more cost-effective with acceptable clinical outcomes.

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.

Microbial Epidemiology of Acute and Perforated Appendicitis: A Post-Hoc Analysis of an EAST Multicenter Study

BACKGROUND

There are significant practice variations in antibiotic treatment for appendicitis, ranging from short-course narrow spectrum to long-course broad-spectrum. We sought to describe the modern microbial epidemiology of acute and perforated appendicitis in adults to help inform appropriate empiric coverage and support antibiotic stewardship initiatives.

METHODS

This is a post-hoc secondary analysis of the Multicenter Study of the Treatment of Appendicitis in America: Acute, Perforated, and Gangrenous (MUSTANG) which prospectively enrolled adult patients (age ≥ 18 years) diagnosed with appendicitis between January 2017 and June 2018 across 28 centers in the United States. We included all subjects with positive microbiologic cultures during primary or secondary (rescue after medical failure) appendectomy or percutaneous drainage. Culture yield was compared between low- and high-grade appendicitis as per the AAST classification.

RESULTS

A total of 3,471 patients were included: 230 (7%) had cultures performed, and 179/230 (78%) had positive results. Cultures were less likely to be positive in grade 1 compared to grades 3, 4, or 5 appendicitis with 2/18 (11%) vs 61/70 (87%) (p < .001). Only 1 subject had grade 2 appendicitis and culture results were negative. E. coli was the most common pathogen and cultured in 29 (46%) of primary appendectomy samples, 16 (50%) of secondary, and 44 (52%) of percutaneous drainage samples.

CONCLUSION

Culturing low-grade appendicitis is low yield. E. coli is the most commonly cultured microbe in acute and perforated appendicitis. This data helps inform empiric coverage for both antibiotics alone and as an adjunct to operative or percutaneous intervention.

Updates on bacterial resistance and empirical antibiotics treatment of complicated acute appendicitis in children

OBJECTIVE

Through historical comparison with our previous study published 10 years ago, this paper aims to provide latest analysis of local bacteriology of acute complicated appendicitis and evaluate the effects of early escalation of potent antibiotics on course of postoperative recovery.

METHODS

A 5-year retrospective review of all children receiving emergency laparoscopic appendicectomies for acute appendicitis from December 2014 to November 2019 was conducted.

RESULTS

257 cases of acute appendicitis were included, 126 were complicated appendicitis (38 gangrenous, 88 ruptured). 96 had positive peritoneal swab culture, 53 (42.1%) grew resistant bacterial strains, including extended spectrum beta-lactamase producing E. coli (ESBL E. coli), Pseudomonas aeruginosa, against traditional empirical triple antibiotics. The prevalence had significantly increased over the past decade (p = 0.008). In our patients, piperacillin/tazobactam, ertapenem, gentamicin provided coverage of 69.8%, 45.3% and 45.3% respectively. For patients with early escalation of postoperative antibiotics, no statistical significance was identified in terms of postoperative complications (p = 0.883), or duration of antibiotics (p = 0.0615).

CONCLUSION

Growing prevalence of resistant strains were observed over the decade. Piperacillin/tazobactam provided the best coverage (69.8%) against resistant bacterial strains in our patients. Early escalation of antibiotics failed to reduce postoperative complications and antibiotics duration.

TYPE OF STUDY

Clinical Research, Retrospective Historical Comparative Study Level of Evidence: Level III.

Sensibilidad antimicrobiana en aislamientos de líquido peritoneal de niños intervenidos por abdomen agudo e infección intraabdominal

Introducción. La apendicitis aguda es causa frecuente de infección intraabdominal en pediatría. La elección del antibiótico se basa en los hallazgos quirúrgicos macroscópicos, el criterio médico, las guías locales o internacionales y, en pocas ocasiones, en el resultado de los aislamientos bacterianos en cultivos de líquido peritoneal y las tasas locales de resistencia. Se analizaron la frecuencia y la sensibilidad microbiológica de los cultivos de muestras de líquido peritoneal de pacientes de un mes a 16 años de edad con manejo quirúrgico por abdomen agudo con sospecha de infección intraabdominal. Materiales y métodos. Se llevó a cabo un estudio prospectivo de cohorte con análisis de las historias clínicas y de resultados de laboratorio de niños sometidos a cirugía por abdomen agudo, en la que el cirujano tomó muestra del líquido peritoneal para la tipificación y determinación de los perfiles de sensibilidad de los microorganismos aislados. Los datos se analizaron con el programa Stata™, versión15.0. Resultados. Se identificaron 303 casos, de los cuales el 93,6 % recibió profilaxis antibiótica con ampicilina-sulbactam y clindamicina-amikacina. El 95,3 % de los procedimientos fueron apendicectomías. Se tomó cultivo del 50 % de las apendicitis perforadas. Se aislaron 48 microorganismos; el más frecuente (2,7 %) fue Escherichia coli positiva para BLEE. El 100 % de los microorganismos resultaron ser sensibles a la amikacina, el 97,2 % al meropenem, y el 94,4 %, a la ciprofloxacina, el cefepime y el ceftazidime. La resistencia más frecuente (37,1 %) fue contra la combinación de ampicilina y sulbactam, en los gérmenes Gram negativos. Discusión. La evaluación de la sensibilidad antimicrobiana de los aislamientos de líquido peritoneal de los procedimientos quirúrgicos en pediatría, es una buena práctica clínica que orienta al cirujano en la adecuada selección del esquema antibiótico y, además, disminuye el riesgo de falla terapéutica temprana y la posibilidad de mayor resistencia o complicaciones infecciosas.

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.

Recovery of aerobic and anaerobic bacteria from patients with acute appendicitis using blood culture bottles

Introducción.

La apendicitis aguda es la primera causa de abdomen agudo; sin embargo, poco se conoce sobre las bacterias asociadas y su perfil de sensibilidad.

Objetivo.

Identificar y determinar el patrón de resistencia de las bacterias aerobias y anaerobias aisladas en cultivo de líquido periapendicular tomado de los pacientes con apendicitis aguda, y establecer la proporción de bacterias según la fase clínica.

Materiales y métodos.

Se llevó a cabo un estudio descriptivo y prospectivo en el Hospital Universitario de San José de Bogotá (Colombia), en pacientes mayores de 16 años sometidos a apendicectomía abierta. Se tomaron muestras de líquido periapendicular, las cuales se sembraron directamente en botellas de hemocultivos para aerobios y anaerobios.

Resultados.

Se incluyeron 154 pacientes. Del total de cultivos, el 87 % (n=134) fueron positivos: 77 % (n=118) para aerobios y 51 % (n=79) para anaerobios. La proporción de cultivos positivos fue inferior en los casos de apendicitis no complicada, en comparación con aquellos de apendicitis complicada (80 % (66/83) Vs. 95 % (67/71); p=0,003). Los microorganismos aislados con mayor frecuencia fueron: Escherichia coli (53 %) (n=84), Bacteroides sp. (25 %) (n=25), Propionibacterium acnes (21 %) (n=21), Staphylococci coagulasa negativo (17 %) (n=27), Enterococcus sp. (10 %) (n=15) y Fusobacterium sp. (11 %) (n=11). La sensibilidad de E. coli a la amplicilina sulbactam fue de 30 %. La sensibilidad de Bacteroides spp. a la clindamicina y la ampicilina sulbactam fue de 91 %. El 100 % de los anaerobios fueron sensibles a piperacilina tazobactam, ertapenem, meropenem y metronidazol.

Conclusiones.

Los cultivos intraoperatorios son pertinentes en la apendicitis para determinar el patrón epidemiológico local, y establecer los antibióticos profilácticos y terapéuticos para esta enfermedad. Su siembra directa en botellas de hemocultivo permite una gran recuperación de microorganismos.

Microbiota of Children With Complex Appendicitis: Different Composition and Diversity of The Microbiota in Children With Complex Compared With Simple Appendicitis

BACKGROUND

Two types of appendicitis are hypothesized, simple and complex, with potential different treatment strategies. To improve differentiation, underlying pathogeneses need to be further unraveled.

AIM

To determine if the microbial composition in the appendix differs between children with simple and complex appendicitis.

METHODS

Two-center, prospective cohort study including 40 children (0-17 years old) undergoing appendectomy for suspected appendicitis. Appendix tissue was used for IS-pro analysis to identify bacterial species by their length of 16S-23S rDNA interspacer (IS) region. Cluster analysis, based on IS-profiles, and correspondence with type of appendicitis, using Fisher exact test, was performed. Simple and complex appendicitis were compared regarding bacterial presence, intensity and diversity, using Fisher exact test and Mann-Whitney U test, respectively.

RESULTS

Appendicitis was confirmed in 36 of 40 patients (16 simple, 20 complex). Cluster analysis identified 2 clusters, encompassing 34 patients. Distribution of simple and complex appendicitis was 12 (80%) and 3 (20%) versus 3 (16%) and 16 (84%) patients for clusters 1 and 2, respectively (P < 0.001). Complex appendicitis was on phylum level characterized by an increased intensity (Bacteroidetes P = 0.001, Firmicutes, Actinobacteria, Fusobacteria and Verrucomicrobia (FAFV) P = 0.005 and Proteobacteria P < 0.001) and diversity (Bacteroidetes P = 0.001 and Proteobacteria P = 0.016) and an increased abundance of 5 species (Alistipes finegoldii P = 0.009, Bacteroides fragilis P = 0.002, Escherichia coli P = 0.014, Parvimonas micra P = 0.022 and Sutterella spp P = 0.026).

CONCLUSIONS

The microbial composition of the appendix differs between children with simple and complex appendicitis, regarding both composition and diversity. Future research should focus on the role of these bacteria in the pathogenesis of both types and its implications for preoperative diagnostics.

An Atypical Case of Abdominal Pain in a Toddler: A Diagnostic Challenge

Abdominal pain in the pediatric patient presents a unique diagnostic challenge for emergency department (ED) providers due to the wide range of possible etiologies and sequelae. The list of differential diagnoses is extensive and includes the spectrum of conditions that range from benign and self-limiting to those that are potentially life-threatening. This article describes a case of a young toddler with an acute appendicitis complicated by perforation and abscess formation. Although acute appendicitis is uncommon in infants and younger children, it does occur and, as this case illustrates, is often misdiagnosed, which leads to delayed treatment and a higher incidence of complications. This article includes a discussion of the challenges faced by ED providers in the clinical-decision making process when caring for a pediatric patient with abdominal pain due to an acute appendicitis. This discussion includes the age-associated epidemiology, pathophysiology, clinical presentation, and evidence-based recommendations for diagnosis and treatment.

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.

Pus Samples in Complicated Appendicitis: An Important Investigation or a Waste of Resources: A Prospective Cohort Study

BACKGROUND AND AIMS:

Appendicitis is a common presentation to hospital with appendectomy being the treatment of choice. Pre-operative administration of broad-spectrum antibiotics is common, but obtaining intra-abdominal pus samples is not. After an initial 6-month retrospective audit and departmental teaching on the importance of intra-peritoneal pus sampling, we aimed to determine whether intra-operative pus samples changed antibiotic management.

MATERIALS AND METHODS:

Following the initial audit cycle, a 6-month prospective cohort study was conducted. Clinical data were collected on a predetermined proforma to assess the effectiveness of the intervention and antibiotic prescribing practice. The data collected during the whole 1-year period was analyzed.

RESULTS:

During the 1-year period, 440 patients were identified as undergoing a laparoscopic procedure. After exclusion, 261 patients were identified as undergoing laparoscopic appendectomies, of which 141 (54%) were classified as complicated laparoscopic appendectomies. A total of 35 out of 141 (25%) pus samples were sent of which 24 (17%) resulted in positive cultures, with only nine of these positive cultures reported prior to the patient being discharged. No patient had their antibiotic regimen changed as a result of the culture results. There were three cases of cultures resistant to local antibiotics, but without significant clinical outcome. One of these patients developed a post-operative complication, but the antibiotic regimen was changed to broad spectrum rather than a specific antibiotic based on culture sensitivity. Of the 141 patients with complicated laparoscopic appendectomies, five (3.5%) developed post-operative complications: one readmission requiring a laparoscopic washout for pelvic collection, three (2%) cases of pelvic collections managed conservatively, and one case of prolonged paralytic ileus managed non-operatively.

CONCLUSION:

Overall, none of the patients with positive cultures had a change in prescribed antibiotics based on culture results. Hence, the routine practice of intra-peritoneal pus sampling following complicated appendicitis remains of little clinical value.

Perforation risk in pediatric appendicitis: assessment and management

Perforated appendicitis, as defined by a visible hole in the appendix or an appendicolith free within the abdomen, carries significant morbidity in the pediatric population. Accurate diagnosis is challenging as there is no single symptom or sign that accurately predicts perforated appendicitis. Younger patients and those with increased duration of symptoms are at higher risk of perforated appendicitis. Elevated leukocytosis, bandemia, high C-reactive protein, hyponatremia, ultrasound, and CT are all useful tools in diagnosis. Distinguishing patients with perforation from those without is important given the influence of a perforation diagnosis on the management of the patient. Treatment for perforated appendicitis remains controversial as several options exist, each with its indications and merits, illustrating the complexity of this disease process. Patients may be managed non-operatively with antibiotics, with or without interval appendectomy. Patients may also undergo appendectomy early in the course of their index hospitalization. Factors known to predict failure of non-operative management include appendicolith, leukocytosis greater than 15,000 white blood cells per microliter, increased bands, and CT evidence of disease beyond the right lower quadrant. In this review, the indications and benefits of each treatment strategy will be discussed and an algorithm to guide treatment decisions will be proposed.

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).

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.

Pediatric Appendicitis

Appendicitis is one of the most common surgical pathologies in children. It can present with right lower quadrant pain. Scoring systems in combination with selective imaging and surgical examination will diagnose most children with appendicitis. Clinical pathways should be used. Most surgical interventions for appendicitis are now almost exclusively laparoscopic, with trials demonstrating better outcomes for children who undergo index hospitalization appendectomies when perforated. Nonoperative management has a role in the treatment of both uncomplicated and complicated appendicitis. This article discusses the workup and management, modes of treatment, and continued areas of controversy in pediatric appendicitis.

The Role of DNA Amplification and Cultural Growth in Complicated Acute Appendicitis

Bacterial growth of peritoneal fluid specimens obtained during surgical procedures for acute appendicitis may be useful to optimize further antibiotic therapy in complicated cases. DNA amplification represents a fast technique to detect microbial sequences. We aimed to compare the potential of DNA amplification versus traditional bacterial growth culture highlighting advantages and drawbacks in a surgical setting. Peritoneal fluid specimens were collected during surgery from 36 children who underwent appendectomy between May and December 2012. Real-time polymerase chain reaction (RT-PCR) and cultures were performed on each sample. RT-PCR showed an amplification of 16S in 18/36 samples, Escherichia coli (in 7 cases), Pseudomonas aeruginosa (3), Fusobacterium necrophorum (3), Adenovirus (2), E.coli (1), Klebsiella pneumoniae (1), Serratia marcescens/Enterobacter cloacae (1). Bacterial growth was instead observed only in four patients (3 E.coli and 1 P.aeruginosa and Bacteroides ovatus). Preoperative C-reactive protein and inflammation degree, the most reliable indicators of bacterial translocation, were elevated as expected. DNA amplification was a quick and useful method to detect pathogens and it was even more valuable in detecting aggressive pathogens such as anaerobes, difficult to preserve in biological cultures; its drawbacks were the lack of biological growths and of antibiograms. In our pilot study RT-PCR and cultures did not influence the way patients were treated.

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.

Response-based therapy for ruptured appendicitis reduces resource utilization

PURPOSE

We examined the effectiveness of a postoperative ruptured appendicitis protocol that eliminated Pseudomonas coverage and based the duration of IV antibiotic treatment and length of hospital stay on the patient's clinical response.

METHODS

In our new protocol, IV antibiotics were administered until the patient met discharge criteria: adequate oral intake, pain control with oral medications, and afebrile for 24h. We collected data on all patients with ruptured appendicitis at our institution following protocol implementation (May 1, 2012, to April 30, 2013) and compared them to a control group.

RESULTS

306 patients were treated (154 prior protocol, 152 new protocol). The new clinical response-based protocol led to a decrease in hospital stay from 134h (SD 66.1) to 94.5h (SD 61.7) (p<0.001) and total cost of care per patient also decreased from $13,610 (SD $6859) to $9870 (SD $5670) (p<0.001).

CONCLUSION

Our clinical response-based protocol for pediatric patients with ruptured appendicitis decreased LOS, cost, and IV antibiotics use without significant changes in adverse events.

Bacteriology and changes in antibiotic susceptibility in adults with community-acquired perforated appendicitis

This study evaluated bacterial etiology and antibiotic susceptibility in patients diagnosed with community-acquired perforated appendicitis over a 12-year-period. We retrospectively reviewed records of adult patients diagnosed with perforated appendicitis at an 800-bed teaching hospital between January 2000 and December 2011. In total, 415 culture-positive perforated appendicitis cases were analyzed. Escherichia coli was the most common pathogen (277/415, 66.7%), followed by Streptococcus species (61/415, 14.7%). The susceptibility of E. coli to ampicillin, piperacillin/tazobactam, ceftriaxone, cefepime, amikacin, gentamicin, and imipenem was 35.1%, 97.1%, 97.0%, 98.2%, 98.9%, 81.8%, and 100%, respectively. The overall susceptibility of E. coli to quinolones (ciprofloxacin or levofloxacin) was 78.7%. During the study period, univariate logistic regression analysis showed a significant decrease in E. coli susceptibility to quinolones (OR = 0.91, 95% CI 0.84-0.99, P = 0.040). We therefore do not recommend quinolones as empirical therapy for community-acquired perforated appendicitis.

[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.

Acute appendicitis in children is associated with an abundance of bacteria from the phylum Fusobacteria

BACKGROUND

Although luminal obstruction has traditionally been viewed as the underlying cause of appendicitis, recent evidence has suggested that the disease may result directly from invasion by specific pathogens, e.g. Fusobacterium nucleatum. The purpose of this study was to survey microbial communities within pediatric appendectomy specimens using a culture-independent approach.

METHODS

We performed 16S ribosomal gene sequence analysis to profile the microbiota present within luminal fluid obtained from 22 pediatric appendectomy specimens. These included 10 simple appendicitis cases, 5 perforated appendicitis cases, 2 interval appendectomies, and 5 incidental appendectomies.

RESULTS

Samples could be divided into 2 distinct clusters based upon the composition of the appendiceal bacterial communities. Appendicitis samples contained an increased abundance of Fusobacterium spp. and a reduced abundance of Bacteroides spp. relative to non-appendicitis cases. Appendicitis samples also contained variable amounts of other oral taxa such as Porphyromonas, Parvimonas, and Gemella, whereas these taxa were generally absent from non-appendicitis samples.

CONCLUSIONS

Acute appendicitis is associated with an abundance of Fusobacterium spp. and other pathogens commonly found in the oral cavity. Further research is needed to determine whether these organisms directly cause appendicitis or rather proliferate in the appendix as a secondary consequence of inflammation.

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.

[Bacteriology of community-acquired peritonitis in children treated in the university hospital of Marrakech]

INTRODUCTION

The available microbiological data on community-acquired peritonitis in children are inadequate, and antibiotic therapy is not consensual. Our work aims to study the bacteriology of peritonitis in children in our region and discuss the appropriate antibiotherapy.

PATIENTS AND METHODS

A descriptive study spread over one year. We collected cases of peritonitis in which a microbiological study of peritoneal fluid was performed.

RESULTS

Of 38 cases, the most frequently isolated bacteria is Escherichia coli (E. coli) (50%). Its sensitivity was 64% to amoxicillin-clavulanate, 93.33% to third generation cephalosporins (C3G) and 100% to ertapenem and aminozides.

CONCLUSION

We find a high rate of resistance of E. coli to amoxicillin-clavulanic acid. This prompts us to reconsider our therapeutic approach. We believe that the association C3G+aminoglycoside+metronidazole should be used first-line in the pediatric peritonitis in our context.

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.

Diagnosis and management of pediatric appendicitis, intussusception, and Meckel diverticulum

Three of the most common causes of surgical abdominal pain in pediatric patients include appendicitis, Meckel diverticulum, and intussusception. All 3 can present with right lower quadrant pain, and can lead to significant morbidity and even mortality. Although ultrasound is the preferred method of diagnosis with appendicitis and intussusception, considerable variety exists in the modalities needed in the diagnosis of Meckel diverticulum. This article discusses the pathways to diagnosis, the modes of treatment, and the continued areas of controversy.