The microbiome of the appendix differs in patients with and without appendicitis: A prospective cohort study.

BACKGROUND: Appendicitis seems to be a disease of infectious origin, but the detailed pathogenesis is unknown. We aimed to investigate the microbiome of the appendix lumen in patients with and without appendicitis, including a comparison of the subgroups of complicated versus uncomplicated appendicitis. METHODS: This prospective observational cohort study included adult patients undergoing laparoscopic appendectomy for suspected appendicitis. According to histopathologic findings, the investigated groups consisted of patients with and without appendicitis, including subgroups of complicated versus uncomplicated appendicitis based on the surgical report. A swab of the appendix lumen was analyzed for genetic material from bacteria with shotgun metagenomics, and outcomes included analyses of microbiome diversity and differential abundance of bacteria. RESULTS: A total of 53 swabs from patients with suspected appendicitis were analyzed: 42 with appendicitis (16 complicated) and 11 without appendicitis. When comparing patients with and without appendicitis, they were equally rich in bacteria (alpha diversity), but the microbiome composition was dissimilar between these groups (beta diversity) (P < .01). No consistent bacterial species were detected in all patients with appendicitis, but a least 3 genera (Blautia, Faecalibacterium, and Fusicatenibacter) and 2 species, Blautia faecis and Blautia wexlerae, were more abundant in patients without appendicitis. For the subgroups complicated versus uncomplicated appendicitis, both measures for microbiome diversity were similar. CONCLUSION: The appendix microbiome composition of genetic material from bacteria in adult patients with and without appendicitis differed, but the microbiome was similar for patients with complicated versus uncomplicated appendicitis. Trial registration NCT03349814.

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.

Hungatella hathewayi bacteremia due to acute appendicitis: A case report and a narrative review.

Hungatella species, including Hungatella hathewayi and Hungatella effluvii, previously identified as part of the Clostridium genus, are anaerobic bacteria primarily residing in the gut microbiome, with infrequent implications in human infections. This article presents the case of an 87-year-old Asian male admitted for a hyperosmolar hyperglycemic state with septic shock secondary to Hungatella hathewayi bacteremia originating from acute appendicitis. Remarkably, the bacterium was detected in the blood 48 hours before the emergence of clinical and radiographic evidence of acute appendicitis. Additionally, we conducted a literature review to identify all documented human infections caused by Hungatella species. Timely microbial identification in such cases is essential for implementing targeted antibiotic therapy and optimizing clinical outcomes.

Beyond a vestigial organ: effects of the appendix on gut microbiome and colorectal cancer.

The role of appendectomy in the pathogenesis of colorectal cancer (CRC) is a recent topic of contention. Given that appendectomy remains one of the most commonly performed operations and a first-line management strategy of acute appendicitis, it is inherently crucial to elucidate the association between prior appendectomy and subsequent development of CRC, as there may be long-term health repercussions. In this review, we summarize the data behind the relationship of CRC in post-appendectomy patients, discuss the role of the microbiome in relation to appendectomy and CRC pathogenesis, and provide an appraisal of our current understanding of the function of the appendix. We seek to piece together the current landscape surrounding the microbiome and immunological changes in the colon post-appendectomy and suggest a direction for future research involving molecular, transcriptomic, and immunologic analysis to complement our current understanding of the alterations in gut microbiome.

A comprehensive microbial analysis of pediatric patients with acute appendicitis.

BACKGROUND: Pathogenesis of pediatric acute appendicitis (AA) is yet to be elucidated. Therefore, we performed a comprehensive microbial analysis of saliva, feces, and appendiceal lumen of AA patients using 16S ribosomal RNA (rRNA) gene amplicon sequencing to elucidate the pathogenesis of pediatric AA. METHODS: This study included 33 AA patients and 17 healthy controls (HCs) aged <15 y. Among the AA patients, 18 had simple appendicitis, and 15 had complicated appendicitis. Salivary and fecal samples were obtained from both groups. The contents of the appendiceal lumen were collected from the AA group. All samples were analyzed using 16S rRNA gene amplicon sequencing. RESULTS: The relative abundance of Fusobacterium was significantly higher in the saliva of AA patients as compared to that in HCs (P = 0.011). Bacteroides, Escherichia, Fusobacterium, Coprobacillus, and Flavonifractor were significantly increased in the feces of AA patients, as compared to that in HCs (P = 0.020, 0.010, 0.029, 0.031, and 0.002, respectively). In the appendiceal lumen, Bacteroides, Parvimonas, Fusobacterium, and Alloprevotella were the top bacterial genera with an average relative abundance >5% (16.0%, 9.1%, 7.9%, and 6.0%, respectively). CONCLUSIONS: The relative abundance of Fusobacterium was high in the appendiceal lumen of pediatric AA patients. Moreover, the relative abundance of Fusobacterium was significantly higher in the saliva and feces of pediatric AA patients than in those of healthy children. These results suggest that ectopic colonization of oral Fusobacterium in the appendix might play an important role in the pathogenesis of pediatric AA.

Non-culture-based studies of the appendiceal microbiota: a systematic review.

Aims: To review studies examining the appendiceal microbiota and microbial changes in acute appendicitis. Methods: After a systematic literature search, 11 studies examining the appendiceal microbiota (414 samples) using non-culture-based methods were included. Results: The appendiceal microbiota showed decreased α-diversity compared with fecal microbiota. Inflamed and uninflamed appendices showed differences in ß-diversity, and there was an increased abundance of oral-associated bacteria in inflamed versus uninflamed appendices. Conclusion: The appendiceal microbiota exhibits lower α-diversity than the fecal microbiota, with an increased abundance of oral-associated bacteria. Compared with uninflamed appendices, the appendix microbiota in acute appendicitis also showed increased abundance of oral-associated bacteria, but no bacterial profile unique to either complicated or uncomplicated appendicitis was found.

This article represents a summary of the current literature examining the bacteria in the human appendix. We aimed to describe the bacterial community in the appendix and look for evidence of bacterial differences between diseased and healthy appendices, as well as evidence of bacteria being the cause of acute appendicitis. We found that the bacteria in the appendix are different from the bacteria in stool. Furthermore, bacteria are different when comparing diseased and healthy appendices. The diseased appendix had more types of bacteria that are normally found in the mouth than the healthy appendix. Our summary did not find any evidence that bacteria are the main cause of developing acute appendicitis.

Lacticaseibacillus rhamnosus dfa1 Attenuate Cecal Ligation-Induced Systemic Inflammation through the Interference in Gut Dysbiosis, Leaky Gut, and Enterocytic Cell Energy.

Despite an uncommon condition, the clinical management of phlegmon appendicitis (retention of the intra-abdominal appendiceal abscess) is still controversial, and probiotics might be partly helpful. Then, the retained ligated cecal appendage (without gut obstruction) with or without oral Lacticaseibacillus rhamnosus dfa1 (started at 4 days prior to the surgery) was used as a representative model. At 5 days post-surgery, the cecal-ligated mice demonstrated weight loss, soft stool, gut barrier defect (leaky gut using FITC-dextran assay), fecal dysbiosis (increased Proteobacteria with reduced bacterial diversity), bacteremia, elevated serum cytokines, and spleen apoptosis without kidney and liver damage. Interestingly, the probiotics attenuated disease severity as indicated by stool consistency index, FITC-dextran assay, serum cytokines, spleen apoptosis, fecal microbiota analysis (reduced Proteobacteria), and mortality. Additionally, impacts of anti-inflammatory substances from culture media of the probiotics were demonstrated by attenuation of starvation injury in the Caco-2 enterocyte cell line as indicated by transepithelial electrical resistance (TEER), inflammatory markers (supernatant IL-8 with gene expression of TLR4 and NF-κB), cell energy status (extracellular flux analysis), and the reactive oxygen species (malondialdehyde). In conclusion, gut dysbiosis and leaky-gut-induced systemic inflammation might be helpful clinical parameters for patients with phlegmon appendicitis. Additionally, the leaky gut might be attenuated by some beneficial molecules from probiotics.

Jaundice and Thrombocytopenia in an acute abdomen with concurrent Appendicitis and spontaneous Rectal perforation: An unusual presentation of human leptospirosis.

Leptospirosis, a bacterial infection attributed to the group leptospira, remains a globally emerging public-health issue in many endemic tropical, subtropical and temperate zones of the world. The burden is expected to inflate with population shifts related to violent storms and urban floods leading to poor housing and inadequate sanitation. Leptospirosis may mimic other illnesses such as influenza, dengue fever, typhoid and malaria due to its myriad presentation ranging from a mild, self-limiting febrile illness to hepatorenal dysfunction, myocarditis, pulmonary haemorrhage, meningitis, optic neuritis and rhabdomyolysis. The classical gastrointestinal manifestation of leptospirosis without hepatorenal dysfunction (Weil's disease) is a rare entity. We report a rare presentation of concurrent appendicitis and rectal perforation in a patient, whose jaundice and thrombocytopenia led to a suspicion of leptospirosis, confirmed by serology and fulfilment of parameters under the modified Faine's criteria. The patient was managed successfully and discharged in a stable condition.

Roseomonas gilardii in patient with leukemia and acute appendicitis: case report and review.

Appendicitis is one of the most common abdominal conditions requiring emergency surgery. However, acute appendicitis in patients with leukemia is a rare condition. We report herein the case of an 18-year-old female with acute lymphoblastic leukemia (ALL), who was hospitalized in hematology department because of abdominal pain and fever. Ultrasound (US) of the abdomen revealed appendicitis and the patients underwent open appendectomy. The patient recovered without complications and was discharged in a good condition. The day of the operation blood and peritoneal fluid cultures were taken and Roseomonas gilardii was detected and healed empirically. The correct diagnosis of appendicitis in patients with leukemia and their management is challenging for physicians. Very rare microorganisms can be detected in these patients.

Modified Antibiotic Regimen for Pediatric Complicated Appendicitis to Reduce Infectious Morbidity in Taiwan.

We compared our previous hospital-based antibiotic protocol and an optimum modified one by reviewing hospital records of children younger than 18 years with complicated appendicitis between 2010-2016. The modified protocol showed no infectious morbidity, which is significantly different from that of our previous protocol (mortality rate, 21.4%). An optimum hospital-based antibiotic protocol for complicated appendicitis can reduce the infectious morbidity rate without increasing hospital cost.

Acute appendicitis is associated with appendiceal microbiome changes including elevated Campylobacter jejuni levels.

OBJECTIVES: To compare the appendiceal microbiomes and examine the prevalence of Campylobacter species in the appendices of adult subjects with confirmed acute non-perforated appendicitis and controls with healthy appendices. DESIGN: Archived samples of formalin-fixed paraffin-embedded appendiceal tissues were obtained from 50 consecutive female subjects who underwent appendectomy for acute, non-perforated appendicitis, and 35 consecutive female controls who underwent incidental appendectomy during gynaecological surgery. RESULTS: 16S rRNA gene sequencing revealed that the relative abundances (RAs) of the major phyla in appendiceal tissues (Firmicutes, Proteobacteria, Bacteroidetes, and Actinobacteria) were similar in both groups. Beta diversity was significantly different due to differences in Bacteroidetes and Proteobacteria (p<0.0001). Within Proteobacteria, RAs of classes Alphaproteobacteria (~21%, fold change (FC)=1.31, false discovery rate (FDR) p value=0.03) and Epsilonproteobacteria (~1%, FC=0.25, FDR p value>0.05) were increased in acute appendicitis samples. RAs of unknown genera from families Burkholderiaceae and Enterobacteriaceae were decreased in appendicitis samples, and 14 genera were increased, including Neisseria, Acinetobacter and Campylobacter. Quantitative PCR revealed that levels of Campylobacter jejuni DNA, but not other Campylobacter species or pathogens tested, were significantly higher in appendicitis samples than in controls (p=0.013). Using a cut-off of 0.31 pg/µL, 40% of appendicitis cases and 6% of controls were positive for C. jejuni, indicating specificity of 93.7% (95% Cl 79.2 to 99.2), sensitivity of 40.9% (95% Cl 24.7 to 54.5), and OR of 10.38 (Fisher's p value=0.0006, 95% Cl 2.3 to 47.4). CONCLUSIONS: Our findings indicate that Campylobacter jejuni may be a significant cause of acute appendicitis. This supports earlier studies and suggests that targeted antibiotic therapies could be an alternative treatment for a subset of non-complicated acute appendicitis cases.

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.

Successful treatment with matched unrelated donor peripheral blood stem cell transplantation for very severe aplastic anemia in presence of active infections: A case report.

RATIONALE: Very severe aplastic anemia (vSAA) with active infections is always fatal. Adequate infection control before hematopoietic stem cell transplantation is recommended. PATIENT CONCERNS: A 38-year-old woman with vSAA suffered from acute perforated appendicitis and invasive pulmonary fungal infection, and she failed to respond to intense antimicrobial therapies. DIAGNOSIS: She was diagnosed with refractory vSAA with stubborn acute perforated appendicitis and invasive pulmonary fungal infection. INTERVENTIONS: We successfully completed an emergent reduced intensity conditioning-matched unrelated donor (MUD)-peripheral blood stem cell transplantation (PBSCT) as a salvage therapy in the presence of active infections. The conditioning regimens consisted of reduced cyclophosphamide 30 mg/kg/day from day-5 to day-3, fludarabine 30 mg/m/day from day-5 to day-3 and porcine-antilymphocyte immunoglobulin 15 mg/kg/day from day-4 to day-2 without total body irradiation. Cyclosporin A, mycophenolate mofetil and short-term methotrexate were administered as graft-versus-host disease (GVHD) prophylaxis. Neutrophils and platelets were engrafted on day+15 and day+21. Appendiceal abscess and severe pneumonia developed after neutrophil engraftment, which were successfully managed with intense antimicrobial therapy and surgical intervention. OUTCOMES: Only limited cutaneous chronic GVHD was observed 5 months after transplantation. The patient still lives in a good quality of life 2 years after transplantation. LESSONS: Active infections may be no longer a contraindication to hematopoietic stem cell transplantation for some patients with vSAA.

Stromal Cells Covering Omental Fat-Associated Lymphoid Clusters Trigger Formation of Neutrophil Aggregates to Capture Peritoneal Contaminants.

The omentum is a visceral adipose tissue rich in fat-associated lymphoid clusters (FALCs) that collects peritoneal contaminants and provides a first layer of immunological defense within the abdomen. Here, we investigated the mechanisms that mediate the capture of peritoneal contaminants during peritonitis. Single-cell RNA sequencing and spatial analysis of omental stromal cells revealed that the surface of FALCs were covered by CXCL1+ mesothelial cells, which we termed FALC cover cells. Blockade of CXCL1 inhibited the recruitment and aggregation of neutrophils at FALCs during zymosan-induced peritonitis. Inhibition of protein arginine deiminase 4, an enzyme important for the release of neutrophil extracellular traps, abolished neutrophil aggregation and the capture of peritoneal contaminants by omental FALCs. Analysis of omental samples from patients with acute appendicitis confirmed neutrophil recruitment and bacterial capture at FALCs. Thus, specialized omental mesothelial cells coordinate the recruitment and aggregation of neutrophils to capture peritoneal contaminants.

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.

Delay in the diagnosis of measles complicated by pneumonitis and appendicitis in a returning traveller.

A 40-year-old British man presented to the emergency department for the second time in 10 days following a 2-week holiday in Thailand with malaise, bilateral conjunctivitis and a morbilliform rash. He had previously seen his general practitioner and ophthalmology and was diagnosed with conjunctivitis. We confirmed measles following RNA detection on a mouth swab. Four days after admission he developed abdominal pain and a CT abdomen demonstrated acute appendicitis with large appendicoliths. A perforated appendix was identified intraoperatively. Measles RNA was detected in the resected appendix. Preoperatively he developed hypoxia with right upper lobe changes seen on a CT pulmonary angiogram. Bronchoalveolar lavage performed in theatre isolated measles RNA at high level, consistent with measles pneumonitis. He required ventilatory support in the intensive care unit and was also treated with intravenous antibiotics. He made a complete recovery.

Recovery of aerobic and anaerobic bacteria from patients with acute appendicitis using blood culture bottles / Recuperación de bacterias aerobias y anaerobias de pacientes con apendicitis aguda mediante botellas de hemocultivo

Introduction: Acute appendicitis is the first cause of acute abdomen, however, there is a little information about the associated bacteria and its sensibility profile. Objetive: To identify and to determine the resistance pattern of aerobic and anaerobic bacteria isolated in periapendicular fluid cultures taken in patients with acute appendicitis and to establish the proportions of isolates according to the clinical phase. Materials and methods: A descriptive and prospective study was undertaken at the Hospital Universitario de San José (Bogotá, Colombia) of patients older than sixteen years of age, undergoing an open appendectomy. A sample of periappendiceal fluid was taken, which was deposited directly into aerobic and anaerobic blood culture bottles. Results: One hundred and fifty-four patients were included. The overall positivity of cultures was 87% (n=1344); 77% (n=118) for aerobes and 51% (n=79) for anaerobes. The proportion of positive cultures was lower in the uncomplicated appendicitis cases as compared to the complicated ones (80% (66/83) vs. 95%(67/71), p = 0.003). The microorganisms isolated most frequently were: Escherichia coli (53%) (n=84); Bacteroides spp. (25%) (n=25); Propionibacterium acnes (21%) (n=21); coagulase negative Staphylococci (17%) (n=27); Enterococcus spp. (11%) (n=15), and Fusobacterium spp. (11%) (n=11). The sensitivity of E. coli to ampicillin/sulbactam was 30%. The sensitivity of Bacteroides spp. to clindamycin and ampicillin/sulbactam was 91%. All anaerobe isolates were sensitive to piperacillin/tazobactam, ertapenem, meropenem and metronidazole. Conclusions: Intraoperative cultures in acute appendicits are relevant in order to determine the local epidemiological pattern and to establish prophylactic and therapeutic antibiotics for this pathology; direct inoculation in blood culture bottles allows a high recovery of microorganisms.

Introduccción. 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.

Streptococcus pyogenes peritonitis: a rare, lethal imitator of appendicitis.

Streptococcus pyogenes is a common cause of infection. Since 2010, the Centers for Disease Control has noted a 24% rise in invasive S. pyogenes infections with a mortality rate of 10%. We present a case series and review of the English literature. Two patients presented with findings concerning for appendicitis, each underwent laparoscopic appendectomies. Both had diffuse peritoneal inflammation without appendicitis, cultures grew S. pyogenes and both recovered with appropriate antibiotics. Thirty cases were identified in a review of the English literature. The average age was 27 years, 75% were in women, 9% were immunocompromised, 15% had rashes and 88% underwent surgical intervention. Previous work identified female gender, immunosuppression and preceding varicella infection as risk factors for invasive S. pyogenes. Given the similarities to appendicitis, early suspicion can influence antibiotic therapy and possibly improve outcomes.

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.