Bacteriology of histopathologically defined appendicitis in children

Bacterial peritonitis in paediatric appendicitis; microbial epidemiology and antimicrobial management

BACKGROUND

Appendicitis remains a common surgical emergency in children. Empirical antibacterial treatment is indicated to reduce infective complications. We investigate the bacterial pathogens identified intra-operatively during appendectomies in children to guide empirical surgical antimicrobial prophylaxis options.

METHODS

A retrospective analysis of patients (< 18 years old) undergoing an appendectomy across a multisite London hospital (Nov 2019-March 2022) was undertaken. Patient-related outcomes including length of hospital stay (LOS), days of antibacterial therapy (DOT), intra-operative microbiology and post-operative radiology reports were interrogated.

RESULTS

304 patients underwent an appendectomy during this period; 39.1% of patients had intraoperative samples cultured. Bacterial pathogens were found in 73/119 (61.3%) cases; the most common isolates being Escherichia coli (42.0%), Pseudomonas aeruginosa (21.0%), milleri Streptococcus spp. (14.3%) and Bacteroides fragilis (5.9%). Polymicrobial infection was common (32/73). Isolation of Pseudomonas spp. from intra-operative sampling was associated with a greater LOS (7.0 vs. 5.0 days; p = 0.011) but nil effect on the incidence of postoperative collections. Presence of milleri Streptococcus spp. was associated with longer LOS (7.0 vs. 5.0 day; p = 0.007), DOT (12.0 vs. 8.5 day; p = 0.007) but had no observed outcome on postoperative collections (29.4% vs. 18.6%; p = 0.330). 48% of E. coli positive cultures were co-amoxiclav resistant and prolonged LOS compared to the non-resistant group (7.0 vs. 5.0 days; p = 0.040) but had no difference in post-operative collections (29.2% vs. 17.9%; p = 0.260).

CONCLUSION

A high proportion of children with appendicitis have Pseudomonas spp. isolated, leading to a prolonged LOS. Evolving Enterobacterales resistance and the presence of Pseudomonas spp. necessitate extended antibacterial coverage for paediatric appendectomies with evidence of peritonitis.

MICROBIOLOGICAL ANALYSIS OF ABDOMINAL CAVITY EXUDATE, BLOOD AND AFFECTED TISSUES SAMPLES FROM PATIENTS WITH INTRA-ABDOMINAL ABSCESSES IN COMPLICATED INFECTION OF ABDOMINAL CAVITY

OBJECTIVE

The aim: To conduct an analysis of the results of a microbiological examination of biological samples taken from patients with intra-abdominal abscesses.

PATIENTS AND METHODS

Materials and methods: Material for microbiological examination was collected from 60 patients during surgery and transported to laboratory at the same day. Isolation and identification of microbial pure cultures were performed by standard microbiological methods. Statistical analysis was performed using Statistica software.

RESULTS

Results: Analyzing the microbiological research results indicated importance of the sample collecting time (first or repeated surgery). In pa¬tient's blood taken during first surgery it was found a statistically significant predominance of no growth of microflora. In abdominal cav¬ity exudates anaerobic cultures increased statistically significantly in repeated surgery. It was noted that in samples taken during first sur¬gery mixed pathogens were represented mainly by facultative anaerobic cocci, then in repeated surgery anaerobic microorganisms were predominant. Examination of liver abscess content found that monoculture was isolated in 85.7 %. Blood and affected tissue samples in such patients were sterile. Investigation of samples from patients with multiple abdominal cavity abscesses revealed anaerobic microorganisms in 16.7 %. Blood samples of that patients in 40 % were sterile.

CONCLUSION

Conclusions: An analysis showed that in appendicular abscesses content gram-negatives were predominant. Gram-positive bacteria dominated in paravesical abscesses with 65 % isolates from gallbladder and 66.7 % from the affected tissue samples. In liver abscesses gram-positive cocci were isolated in 57.1 %. In multiple abdominal abscesses due to bowel perforation rod-shaped microflora was predominant (76 %) and represented by either obligate aerobes or obligate and facultative anaerobes.

Aspergillus appendicitis complicating chemotherapy of leukemia: A case report and review of the literature

Introduction

The diagnosis of primary Aspergillus appendicitis can be missed or delayed because of its rarity. We report our experience of a case of Aspergillus appendicitis complicating chemotherapy of leukemia.

Presentation of case

A 48-year-old man who was diagnosed with acute myeloid leukemia developed high fever and epigastric pain two weeks after administration of his fourth consolidation chemotherapy. Right lower quadrant tenderness and rebound tenderness were noticed on physical examination, and the abdomen and pelvis computed tomography suggested acute perforated appendicitis with localized peritonitis. Emergency laparoscopy showed an inflamed appendix, which was resected. Pathology reports revealed invasive aspergillosis in the appendix. The patient recovered after high-dose antifungal therapy, although he required prolonged hospitalization.

Discussion

Acute appendicitis is very rarely caused by fungi infection with an overall incidence of up to 1.15 %. Differential diagnosis of fungal appendicitis without pathology report is challenging due to low incidence.

Conclusion

Isolated Aspergillus appendicitis is a rare disease that can progress without appropriate antifungal therapy even after surgical resection of the appendix. Surgeons should pay attention to pathology reports after appendectomy to avoid missing unusual cases, especially in immunocompromised patients.

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Fungal infections principally occur in the immunocompromised.

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Misdiagnosis and incorrect treatment are frequent in this rare disease entity.

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Early diagnosis and prompt surgery with antifungal treatment is best

Characteristics of appendicitis after immune checkpoint inhibitor therapy among cancer patients

PURPOSE

Immune checkpoint inhibitor (ICI) therapy has revolutionized cancer care but is associated with immune-related adverse events (irAEs). Recent case reports raised the concern that acute appendicitis may be an irAE. In this study, we sought to describe the disease course of post-ICI therapy appendicitis and its associated complications.

METHODS

Adult patients who had an International Classification of Diseases code for appendicitis within the first 2 years after initiating ICI therapy from January 2010 to April 2021 and who had imaging evidence of appendicitis were studied retrospectively.

RESULTS

13,991 patients were identified who had ICI exposure during the study period, 44 had codes for appendicitis, 10 of whom met the inclusion criteria. Their median age at the time of diagnosis was 59 years. The median time from ICI therapy initiation to appendicitis onset was 188 days. The most common presenting symptoms were abdominal pain (70%) and fever (40%). Abscesses were present in two patients, and a perforation was present in one. All 10 patients received broad-spectrum antibiotics. Five patients needed surgery or interventional radiology drainage. Nine patients had resolution of appendicitis symptoms after treatment.

CONCLUSION

Post-ICI therapy appendicitis is rare but presents similarly to and has similar complications rates as conventional appendicitis. Appendectomy remains the mainstay of treatment, but its use can be limited in cancer patients. The decision to continue ICI therapy remains at the discretion of the clinician. Further studies are needed to bring awareness to and advance the understanding of this clinical entity.

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

LEVEL OF EVIDENCE

Level III.

Optimising the treatment for uncomplicated acute appendicitis (OPTIMA trial): a protocol for a multicentre, randomised, double-blinded placebo-controlled study

INTRODUCTION

Emerging evidence has shown that an antibiotic first strategy is a viable treatment option for uncomplicated acute appendicitis (AA). Although there has recently been an interest and increase in the use of antibiotics as the primary strategy for treating uncomplicated AA, there is no consensus regarding the optimum antibiotic regimen. In particular, the long-term outcomes of different antibiotic regimens, such as the recurrence rate, still lack evidence. Given that the flora of the appendix is mainly anaerobic bacteria, we hypothesised that antianaerobe regimens could decrease the recurrence rate compared with those that did not include antianaerobic antibiotics.

METHODS AND ANALYSIS

The OPTIMA(Optimising the treatment for uncomplicated acute appendicitis) trial is a multicentre, double-blinded placebo-controlled superiority randomised study aimed to evaluate the role of antianaerobic antibiotics in the resolution of uncomplicated AA. Patients (18-65 years) with uncomplicated AA (without gangrenous, perforated appendicitis, appendiceal abscess, or appendiceal fecaliths) are eligible for inclusion. The primary endpoint of this study is the success rate of the treatment, defined as the resolution of AA resulting in discharge from the hospital without surgical intervention and recurrent symptoms within one year. Secondary endpoints include mortality, postintervention complications, recurrent symptoms up to one year after treatment, hospital stay, sick leave, treatment cost, pain symptom scores and quality of life. Data are reported as the number of cases (%), median (range) and relative risk, which will be analysed using the Mann-Whitney U test or χ² test, as appropriate. P-value<0.05 will be considered significant.

ETHICS AND DISSEMINATION

The protocol has been approved by the Ethics Committee of Jinling Hospital on 13 November 2018 (2018NZKY-027-01). The trial findings will be published in peer-reviewed journals.

TRIAL REGISTRATION NUMBER

ChiCTR1800018896.

Is Routine Intra-operative Gram Stain, Culture, and Sensitivity during an Appendectomy is Effective in Decreasing the Rate of Post-operative Infective Complications?

BACKGROUND: Organisms blamed in acute appendicitis are right predictable and very susceptible to a wide range of broad-spectrum antibiotics. AIM: The aim of the study was to assess the clinical benefit of the routine intra-operative swab during an appendectomy in guiding antibiotic selection. METHODS: Four hundred and thirty patients underwent appendectomy halved into two groups, each 215. In Group 1, an intra-operative swab was routinely obtained for culture/sensitivity. The results of which were reviewed for helping direct antibiotic selection. No intra-operative swabs were obtained in Group 2. Both groups were given single-dose cefotaxime and metronidazole preoperatively intravenously at the time of induction of anesthesia. RESULTS: In swab group, 63/215 cultures (29.3%) revealed pathogens, while (70.7%) were negative or revealed isolated colonic commensals. Most cultures were negative or isolated colonic commensals. Fifty-two/63 cultures (82.54%) were sensitive to both cefotaxime and metronidazole, and only 11/63 (17.46%) reported resistant organisms to cefotaxime but not to metronidazole. Most pathogens were sensitive to empirical antibiotics. Twenty-two/215 patients (10.23%) developed infective complications, most (63.6%) had their cultures from the infected wound yielded different micro-organisms. Only 8/215 (3.72%) in the swab group needed a change in the empirical antibiotics for treating infective complications. In the non-swab group, 19/215 patients (8.83%) developed infective complications. Only 6/215 patients (2.8%) needed a change in the empirical antibiotics for treating infective complications. Collectively, only 14/430 patients (3.25%) required a change in the empirical antibiotics for treating infected wounds. CONCLUSIONS: Routine peritoneal swabs for culture/sensitivity during appendicectomy are of no clinical value. Such practice is considered a waste of laboratory resources and money. A single prophylactic dose of antibiotics has significant role in preventing surgical site infection.

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.

Eggerthella lenta bloodstream infections: two cases and review of the literature

Eggerthella lenta is an emerging and uncommon human pathogen that has been under recognized due to the limitations of phenotypic identification. Here we describe two cases of bacteremia caused by E. lenta and summarize the results of antimicrobial susceptibility testing according to some previous literatures, which illustrate the importance of identification and treatment of unusual organisms. The most reliable antibiotic treatment options to E. lenta appear to be metronidazole, amoxicillin-clavulanate, carbapenems, vancomycin, cefoxitin, chloramphenicol and clindamycin.

Potential Probiotic or Trigger of Gut Inflammation - The Janus-Faced Nature of Cannabidiol-Rich Cannabis Extract

Cannabidiol (CBD) is the major non-psychotropic phytocannabinoid present in Cannabis sativa. In 2018, Congress designated certain C. sativa plant material as "hemp," thus removing it from the DEA's list of controlled substances. As a result, CBD-containing hemp extracts and other CBD products are now widely available and heavily marketed, yet their FDA regulatory status is still hotly debated. The goal of this study was to investigate the effects of a cannabidiol-rich cannabis extract (CRCE) on the gut microbiome and associated histomorphological and molecular changes in the mouse gut mucosa. Male C57BL6/J mice were gavaged with either 0, 61.5, 184.5, or 615 mg/kg/bw of CRCE in sesame oil for 2 weeks (Mon-Fri). Substantial CRCE-induced increases in the relative abundance of A. muciniphila, a bacterial species currently accepted as probiotic, was observed in fecal samples at all doses. This was paralleled by decreases in the relative abundance of other gut bacterial species. Coincident with the observed changes in gut ecology were multiple pro-inflammatory responses, including increased expression of cytokines and chemokines-Il1ß, Cxcl1, and Cxcl2 in the colon tissue. Furthermore, dramatic increases in the relative abundance of A. muciniphila significantly decreased expression of Muc2-a gene intimately associated with gut integrity. Taken together, these findings raise concerns about the safety of long-term CBD usage and underline the need for additional well-designed studies into its tolerability and efficacy.

Streptococcus anginosus is associated with postoperative intraabdominal collections in appendicitis

AIM OF STUDY

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

METHODS

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

MAIN RESULTS

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

CONCLUSION

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

LEVEL OF EVIDENCE

Level II prognosis study.

The intra- and extraluminal appendiceal microbiome in pediatric patients: A comparative study

Intestinal microbiota is involved in metabolic processes and the pathophysiology of various gastrointestinal disorders. We aimed to characterize the microbiome of the appendix in acute pediatric appendicitis comparing extraluminal and intraluminal samples.Between January and June 2015, 29 children (3-17 years, mean age 10.7 ± 3.4 years, sex M:F = 2.6:1) undergoing laparoscopic appendectomy for acute appendicitis were prospectively included in the study. Samples for bacterial cultures (n = 29) and 16S ribosomal desoxyribonucleic acid (rDNA) sequencing (randomly chosen n = 16/29) were taken intracorporeally from the appendiceal surface before preparation ("extraluminal") and from the appendiceal lumen after removal ("intraluminal"). The degree of inflammation was histologically classified into catarrhal, phlegmonous, and gangrenous appendicitis.Seventeen bacterial species were cultivated in 28 of 29 intraluminal samples and 4 species were cultivated in 2 of 29 extraluminal samples. Using 16S rDNA sequencing, 267 species were detected in intraluminal but none in extraluminal samples. Abundance and diversity of detected species differed significantly between histological groups of acute appendicitis in bacterial cultures (P = .001), but not after 16S rDNA sequencing.The appendiceal microbiome showed a high diversity in acute pediatric appendicitis. The intraluminal microbial composition differed significantly depending on the degree of inflammation. As bacteria were rarely found extraluminally by culture and not at all by sequencing, the inflammation in acute appendicitis may start inside the appendix and spread transmurally.

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.

Paediatric splenic and rectovesical pouch abscesses caused by Eggerthella lenta

Paediatric splenic abscesses are rare, but can be fatal. An 8-year-old boy developed recurrent fever and abdominal pain 5 months after undergoing an appendectomy. A CT scan showed splenic and rectovesical pouch abscesses. The patient was successfully treated with antibiotics, and laparoscopic drainage and debridement of pus from the rectovesical pouch abscess. Eggerthella lenta was cultured from the latter lesion. Early diagnosis and treatment resulted in the satisfactory resolution of the infection.

High-throughput 16S rRNA gene sequencing reveals alterations of mouse intestinal microbiota after radiotherapy

The mammalian gastrointestinal tract harbors a highly complex microbial community that comprises hundreds of different types of bacterial cells. The gastrointestinal microbiota plays an important role in the function of the host intestine. Most cancer patients undergoing pelvic irradiation experience side effects such as diarrhea; however, little is currently known about the effects of irradiation on the microorganisms colonizing the mucosal surfaces of the gastrointestinal tract. The aim of this study was to investigate the effects of gamma irradiation on the compositions of the large and small intestinal microbiotas. The gut microbiotas in control mice and mice receiving irradiation treatment were characterized by high-throughput sequencing of the bacterial 16S rRNA gene. Irradiation treatment induced significant alterations in the bacterial compositions of the large and small intestines at the genus level. Unexpectedly, irradiation treatment increased the number of operational taxonomic units in the small intestine but not the large intestine. In particular, irradiation treatment increased the level of the genera Alistipes in the large intestine and increased the level of the genus Corynebacterium in the small intestine. By contrast, compared with that in the corresponding control group, the level of the genera Prevotella was lower in the irradiated large intestine, and the level of the genera Alistipes was lower in the irradiated small intestine. Overall, the data presented here reveal the potential microbiological effects of pelvic irradiation on the gastrointestinal tracts of cancer patients.

Clinical and microbiological characteristics of Eggerthella lenta bacteremia

Eggerthella lenta is an emerging pathogen that has been underrecognized due to historical difficulties with phenotypic identification. Until now, its pathogenicity, antimicrobial susceptibility profile, and optimal treatment have been poorly characterized. In this article, we report the largest cohort of patients with E. lenta bacteremia to date and describe in detail their clinical features, microbiologic characteristics, treatment, and outcomes. We identified 33 patients; the median age was 68 years, and there was no gender predominance. Twenty-seven patients (82%) had serious intra-abdominal pathology, often requiring a medical procedure. Of those who received antibiotics (28/33, 85%), the median duration of treatment was 21.5 days. Mortality from all causes was 6% at 7 days, 12% at 30 days, and 33% at 1 year. Of 26 isolates available for further testing, all were identified as E. lenta by both commercially available matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) systems, and none were found to harbor a vanA or vanB gene. Of 23 isolates which underwent susceptibility testing, all were susceptible to amoxicillin-clavulanate, cefoxitin, metronidazole, piperacillin-tazobactam, ertapenem, and meropenem, 91% were susceptible to clindamycin, 74% were susceptible to moxifloxacin, and 39% were susceptible to penicillin.

Structural modulation of gut microbiota during alleviation of type 2 diabetes with a Chinese herbal formula

The gut microbiota is hypothesized to have a critical role in metabolic diseases, including type 2 diabetes (T2D). A traditional Chinese herbal formula, Gegen Qinlian Decoction (GQD), can alleviate T2D. To find out whether GQD modulates the composition of the gut microbiota during T2D treatment, 187 T2D patients were randomly allocated to receive high (HD, n=44), moderate (MD, n=52), low dose GQD (LD, n=50) or the placebo (n=41) for 12 weeks in a double-blinded trial. Patients who received the HD or MD demonstrated significant reductions in adjusted mean changes from baseline of fasting blood glucose (FBG) and glycated hemoglobin (HbA1c) compared with the placebo and LD groups. Pyrosequencing of the V3 regions of 16S rRNA genes revealed a dose-dependent deviation of gut microbiota in response to GQD treatment. This deviation occurred before significant improvement of T2D symptoms was observed. Redundancy analysis identified 47 GQD-enriched species level phylotypes, 17 of which were negatively correlated with FBG and 9 with HbA1c. Real-time quantitative PCR confirmed that GQD significantly enriched Faecalibacterium prausnitzii, which was negatively correlated with FBG, HbA1c and 2-h postprandial blood glucose levels and positively correlated with homeostasis model assessment of β-cell function. Therefore, these data indicate that structural changes of gut microbiota are induced by Chinese herbal formula GQD. Specifically, GQD treatment may enrich the amounts of beneficial bacteria, such as Faecalibacterium spp. In conclusion, changes in the gut microbiota are associated with the anti-diabetic effects of GQD.

Hitchhiking of host biology by beneficial symbionts enhances transmission

Transmission plays a key role in the evolution of symbiosis. Mixed mode transmission combines horizontal and vertical mechanisms for symbiont acquisition. However, features that enable mixed transmission are poorly understood. Here, we determine the mechanistic basis for the recruitment of the beneficial bacterium, Aeromonas veronii by the leech, Hirudo verbana. We demonstrate that host mucosal secretions complement imperfect symbiont vertical transmission. First, we show that the A. veronii population within secretions originates from the host digestive tract and proliferates synchronously with shedding frequency, demonstrating the coupling of partner biology. Furthermore, leeches are attracted to these castings with oral contact proving sufficient for symbiont transmission. Leech attraction to mucus is not affected by the symbiont state of either the host or mucus, suggesting that A. veronii exploits preexisting host behavior and physiological traits. A dual transmission mode, integrating multiple layers of host contributions, may prove evolutionarily advantageous for a wide range of symbioses. Using such a strategy, host infection is ensured, while also providing access to a higher genetic diversity of symbionts. Countless host-associated microbes exhibit mixed mode transmission, supporting the use of the leech symbiosis as a model for enhancing our understanding of the specificity, establishment and persistence of microbiotas.

Eggerthella lenta bacteremia complicated by spondylodiscitis, psoas abscess, and meningitis

Eggerthella lenta bacteremia is uncommon and generally associated with abdominal sepsis. The organism and its clinical significance have not been well characterized due to historical difficulties with identification. We report a case of severe infection in a paraplegic man complicated by psoas abscess, osteomyelitis, and meningitis and discuss treatment challenges.

Microarray analysis of microbiota of gingival lesions in noma patients

Noma (cancrum oris) is a gangrenous disease of unknown etiology affecting the maxillo-facial region of young children in extremely limited resource countries. In an attempt to better understand the microbiological events occurring during this disease, we used phylogenetic and low-density microarrays targeting the 16S rRNA gene to characterize the gingival flora of acute noma and acute necrotizing gingivitis (ANG) lesions, and compared them to healthy control subjects of the same geographical and social background. Our observations raise doubts about Fusobacterium necrophorum, a previously suspected causative agent of noma, as this species was not associated with noma lesions. Various oral pathogens were more abundant in noma lesions, notably Atopobium spp., Prevotella intermedia, Peptostreptococcus spp., Streptococcus pyogenes and Streptococcus anginosus. On the other hand, pathogens associated with periodontal diseases such as Aggregatibacter actinomycetemcomitans, Capnocytophaga spp., Porphyromonas spp. and Fusobacteriales were more abundant in healthy controls. Importantly, the overall loss of bacterial diversity observed in noma samples as well as its homology to that of ANG microbiota supports the hypothesis that ANG might be the immediate step preceding noma.

Risk factors for noma disease: a 6-year, prospective, matched case-control study in Niger

BACKGROUND

Noma is a poorly studied disease that leads to severe facial tissue destruction in children in developing countries, but the cause remains unknown. We aimed to identify the epidemiological and microbiological risk factors associated with noma disease.

METHODS

We did a prospective, matched, case-control study in Niger between Aug 1, 2001, and Oct 31, 2006, in children younger than 12 years to assess risk factors for acute noma. All acute noma cases were included and four controls for each case were matched by age and home village. Epidemiological and clinical data were obtained at study inclusion. We undertook matched-paired analyses with conditional logistic regression models.

FINDINGS

We included 82 cases and 327 controls. Independent risk factors associated with noma were: severe stunting (odds ratio [OR] 4·87, 95% CI 2·35-10·09) or wasting (2·45, 1·25-4·83); a high number of previous pregnancies in the mother (1·16, 1·04-1·31); the presence of respiratory disease, diarrhoea, or fever in the past 3 months (2·70, 1·35-5·40); and the absence of chickens at home (1·90, 0·93-3·88). After inclusion of microbiological data, a reduced proportion of Fusobacterium (4·63, 1·61-13·35), Capnocytophaga (3·69, 1·48-9·17), Neisseria (3·24, 1·10-9·55), and Spirochaeta in the mouth (7·77, 2·12-28·42), and an increased proportion of Prevotella (2·53, 1·07-5·98), were associated with noma. We identified no specific single bacterial or viral pathogen in cases.

INTERPRETATION

Noma is associated with indicators of severe poverty and altered oral microbiota. The predominance of specific bacterial commensals is indicative of a modification of the oral microbiota associated with reduced bacterial diversity.

FUNDING

Gertrude Hirzel Foundation.

Complete genome sequence of the bile-resistant pigment-producing anaerobe Alistipes finegoldii type strain (AHN2437(T))

Alistipes finegoldii Rautio et al. 2003 is one of five species of Alistipes with a validly published name: family Rikenellaceae, order Bacteroidetes, class Bacteroidia, phylum Bacteroidetes. This rod-shaped and strictly anaerobic organism has been isolated mostly from human tissues. Here we describe the features of the type strain of this species, together with the complete genome sequence, and annotation. A. finegoldii is the first member of the genus Alistipes for which the complete genome sequence of its type strain is now available. The 3,734,239 bp long single replicon genome with its 3,302 protein-coding and 68 RNA genes is part of the G enomic E ncyclopedia of Bacteria and Archaea project.

Non contiguous-finished genome sequence and description of Alistipes obesi sp. nov

Alistipes obesi sp. nov. strain ph8(T) is the type strain of A. obesi, a new species within the genus Alistipes. This strain, whose genome is described here, was isolated from the fecal flora of a 26-year-old woman suffering from morbid obesity. A. obesi is an obligately anaerobic rod. Here we describe the features of this organism, together with the complete genome sequence and annotation. The 3,162,233 bp long genome (1 chromosome but no plasmid) contains 2,623 protein-coding and 49 RNA genes, including three rRNA genes.

Microbial composition of human appendices from patients following appendectomy

The human appendix has historically been considered a vestige of evolutionary development with an unknown function. While limited data are available on the microbial composition of the appendix, it has been postulated that this organ could serve as a microbial reservoir for repopulating the gastrointestinal tract in times of necessity. We aimed to explore the microbial composition of the human appendix, using high-throughput sequencing of the 16S rRNA gene V4 region. Seven patients, 5 to 25 years of age, presenting with symptoms of acute appendicitis were included in this study. Results showed considerable diversity and interindividual variability among the microbial composition of the appendix samples. In general, however, Firmicutes was the dominant phylum, with the majority of additional sequences being assigned at various levels to Proteobacteria, Bacteroidetes, Actinobacteria, and Fusobacteria. Despite the large diversity in the microbiota found within the appendix, however, a few major families and genera were found to comprise the majority of the sequences present. Interestingly, also, certain taxa not generally associated with the human intestine, including the oral pathogens Gemella, Parvimonas, and Fusobacterium, were identified among the appendix samples. The prevalence of genera such as Fusobacterium could also be linked to the severity of inflammation of the organ. We conclude that the human appendix contains a robust and varied microbiota distinct from the microbiotas in other niches within the human microbiome. The microbial composition of the human appendix is subject to extreme variability and comprises a diversity of biota that may play an important, as-yet-unknown role in human health.

There are currently limited data available on the microbial composition of the human appendix. It has been suggested, however, that it may serve as a “safe house” for commensal bacteria that can reinoculate the gut at need. The present study is the first comprehensive view of the microbial composition of the appendix as determined by high-throughput sequencing. We have determined that the human appendix contains a wealth of microbes, including members of 15 phyla. Important information regarding the associated bacterial diversity of the appendix which will help determine the role, if any, the appendix microbiota has in human health is presented.

Genome sequence and description of Alistipes senegalensis sp. nov

Alistipes senegalensis strain JC50^T is the type strain of A. senegalensis sp. nov., a new species within the Alistipes genus. This strain, whose genome is described here, was isolated from the fecal flora of an asymptomatic patient. A. senegalensis is an anaerobic Gram-negative rod-shaped bacterium. Here we describe the features of this organism, together with the complete genome sequence and annotation. The 4,017,609 bp long genome (1 chromosome, but no plasmid) contains 3,113 protein-coding and 50 RNA genes, including 5 rRNA genes.

Risk and prognostic factors among patients with bacteremia due to Eggerthella lenta

Eggerthella lenta is a Gram-positive non-spore forming anaerobic commensal bacilli that can cause bacteremia due to abdominal or soft tissue sources. Patients are frequently bedridden and infection is associated with a high mortality rate. Absence of fever at presentation and need for ICU stay are risk factors for 30-day mortality.

Streptococcus milleri in intraabdominal abscesses in children after appendectomy: incidence and course

INTRODUCTION

Intraabdominal abscesses are a common complication after appendectomy, especially in children. In this study, we describe the incidence and course of this complication in relation to the cultured pathogens found in intraabdominal abscesses.

METHODS

The charts of all patients between 1 and 18 years of age undergoing appendectomy in 3 hospitals between January 2006, and July 2009, were retrospectively reviewed. Presence of an intraabdominal abscess was confirmed with abdominal ultrasound examination. We collected all details concerning the appendectomy, pus cultures, and postoperative course in these patients.

RESULTS

Two hundred fifty-nine patients underwent appendectomy during the study period. Subsequently, abdominal ultrasound studies showed an intraabdominal abscess in 18 (7%) patients. Intraabdominal abscesses developed more frequently after perforated appendicitis (23%) than after simple appendicitis (2%). The incidence of postoperative abscesses did not differ significantly between open (5.6%) or laparoscopic (6.3%) appendectomy. However, the rate was high (38%) in the patients in whom the appendectomy was converted from laparoscopic to open. In 15 out of the 18 patients with a postoperative abscess drainage was performed. In pus cultures of the drained abscesses Streptococcus milleri and Escherichia coli were the most commonly isolated pathogens. Presence of S milleri was associated with prolonged hospital stay (13.9 versus 9.0 days, P = .105) and prolonged antibiotic treatment (11.3 versus 4.8 days, P = .203).

CONCLUSIONS

The incidence of intraabdominal abscesses is high after perforated appendicitis in children (23%). Our data suggest that the presence of S milleri correlates with a more complicated postoperative course after appendectomy in children.

Appendectomy versus antibiotic treatment for acute appendicitis

BACKGROUND

Acute appendicitis is one of the most common causes of acute abdominal pain. Present day treatment of choice for acute appendicitis is appendectomy, however complications are inherent to operative treatment. Though surgical appendectomy remains the standard treatment, several investigators have investigated conservative antibiotic treatment of acute appendicitis and reported good results.

OBJECTIVES

Is antibiotic treatment as effective as surgical appendectomy (laparoscopic or open) in patients with acute appendicitis on recovery within two weeks, without major complications (including recurrence) within one year?

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (The Cochrane Library Issue 6, 2011); MEDLINE (until June 2011); EMBASE (until June 2011); Prospective Trial Registers (June 2011) and reference lists of articles.

SELECTION CRITERIA

Randomised and quasi-randomised clinical trials (RCT and qRCT) comparing antibiotic treatment with appendectomy in patients with suspected appendicitis were included. Excluded were studies which primarily focused on the complications of acute appendicitis.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial quality and extracted data. The review authors contacted the trial authors for additional information if required. Statistical analysis was carried out using Review Manager and MetaAnalyst. A non-inferiority analysis was performed, comparing antibiotic treatment (ABT) to the gold standard (appendectomy). By consensus, a 20% margin of non-inferiority was considered clinically relevant.

MAIN RESULTS

Five RCT's (901 patients) were assessed. In total 73.4% (95% CI 62.7 to 81.9) of patients who were treated with antibiotics and 97.4 (95% CI 94.4 to 98.8) patients who directly got an appendectomy were cured within two weeks without major complications (including recurrence) within one year. The lower 95% CI was 15.2% below the 20% margin for the primary outcome.

AUTHORS' CONCLUSIONS

The upper bound of the 95% CI of ABT for cure within two weeks without major complications crosses the 20% margin of appendectomy, so the outcome is inconclusive. Also the quality of the studies was low to moderate, for that reason the results should be interpret with caution and definite conclusions cannot be made. Therefore we conclude that appendectomy remains the standard treatment for acute appendicitis. Antibiotic treatment might be used as an alternative treatment in a good quality RCT or in specific patients or conditions were surgery is contraindicated.

Gastrointestinal microbiome signatures of pediatric patients with irritable bowel syndrome

BACKGROUND & AIMS

The intestinal microbiomes of healthy children and pediatric patients with irritable bowel syndrome (IBS) are not well defined. Studies in adults have indicated that the gastrointestinal microbiota could be involved in IBS.

METHODS

We analyzed 71 samples from 22 children with IBS (pediatric Rome III criteria) and 22 healthy children, ages 7-12 years, by 16S ribosomal RNA gene sequencing, with an average of 54,287 reads/stool sample (average 454 read length = 503 bases). Data were analyzed using phylogenetic-based clustering (Unifrac), or an operational taxonomic unit (OTU) approach using a supervised machine learning tool (randomForest). Most samples were also hybridized to a microarray that can detect 8741 bacterial taxa (16S rRNA PhyloChip).

RESULTS

Microbiomes associated with pediatric IBS were characterized by a significantly greater percentage of the class γ-proteobacteria (0.07% vs 0.89% of total bacteria, respectively; P < .05); 1 prominent component of this group was Haemophilus parainfluenzae. Differences highlighted by 454 sequencing were confirmed by high-resolution PhyloChip analysis. Using supervised learning techniques, we were able to classify different subtypes of IBS with a success rate of 98.5%, using limited sets of discriminant bacterial species. A novel Ruminococcus-like microbe was associated with IBS, indicating the potential utility of microbe discovery for gastrointestinal disorders. A greater frequency of pain correlated with an increased abundance of several bacterial taxa from the genus Alistipes.

CONCLUSIONS

Using 16S metagenomics by PhyloChip DNA hybridization and deep 454 pyrosequencing, we associated specific microbiome signatures with pediatric IBS. These findings indicate the important association between gastrointestinal microbes and IBS in children; these approaches might be used in diagnosis of functional bowel disorders in pediatric patients.

Single incision versus conventional multi-incision appendicectomy for suspected appendicitis

BACKGROUND

Appendicectomy is a well established surgical procedure used in the management of acute appendicitis.  The operation can be performed with minimally invasive surgery (laparoscopic) or as an open procedure. A recent development in appendicectomy has been the introduction of less invasive single incision laparoscopic surgery, using a single multi-luminal port or multiple mono-luminal ports, through a single skin incision. There are yet unanswered questions regarding the efficacy of this new and novel technique including: patient benefit and satisfaction, complications, long-term outcomes, and survival.

OBJECTIVES

The aim of this review is to perform meta-analysis using data from available trials comparing single incision with conventional multi-incision laparoscopic appendicectomy for appendicitis, in order to ascertain any differences in outcome.

SEARCH STRATEGY

We searched the electronic databases including MEDLINE/PubMed (from 1980 to December 2010), EMBASE/Ovid (from 1980 to December 2010) and CENTRAL (The Cochrane Library 2010, Issue 11) with pre-specified terms. We also searched reference lists of relevant articles and reviews, conference proceedings and ongoing trial databases.

SELECTION CRITERIA

Randomised or quasi-randomised controlled trials of patients with appendicitis, or symptoms of appendicitis, undergoing laparoscopic appendicectomy, in which at least one arm involves single incision procedures and another multi-incision procedures.

DATA COLLECTION AND ANALYSIS

There were no RCTs or prospectively controlled trials found that met the inclusion criteria.

MAIN RESULTS

Three authors performed study selection independently.No studies that met the inclusion criteria of this review were identified. Current evidence exists only the form of case-series.This review has been authored as 'empty' pending the results of 5 ongoing trials.

AUTHORS' CONCLUSIONS

No RCTs comparing single incision laparoscopic appendectomy with multi-incision surgery could be identified. No definitive conclusions can be made at this time. Well designed prospective RCTs are required in order to evaluate benefit or harm from laparoscopic surgical approaches for appendicectomy. Until appropriate data has been reported, the institutional polices of healthcare providers must be based on the clinical judgement of experts in the field.

Re-assessment of phenotypic identifications of Bacteroides putredinis to Alistipes species using molecular methods

Alistipes (previously Bacteroides) are strictly anaerobic gram-negative rods that resemble the Bacteroides fragilis group in that most species are bile-resistant and indole-positive; however, they are only weakly saccharolytic and most species produce light brown pigment only on laked rabbit blood agar. In this retrospective study, we re-identified 18 organisms previously identified phenotypically as "Bacteroides putredinis-like", but that did not produce pigment on routine media. The strains were identified with 16S rDNA sequencing and pigment production was evaluated on several different culture media. Only 12/18 strains had molecular identifications of Alistipes species, while the remaining strains phylogenetically resembled Butyricimonas and Odoribacter spp. Pigment production was not a reliable test for those Alistipes strains that are described as pigment producers.

Osteomyelitis of the iliac crest: a rare complication following perforated appendicitis

BACKGROUND

Appendicitis is a common surgical emergency with numerous postoperative infective complications. We report an unusual case of iliac crest osteomyelitis as a late complication following emergency appendectomy for perforated gangrenous appendicitis.

METHODS

Review of the pertinent English language literature.

RESULTS

To the best of our knowledge, this is the first report in the English literature to describe iliac crest osteomyelitis as an infective complication of perforated gangrenous appendicitis. The diagnosis was made with the aid of magnetic resonance imaging and radioisotope bone scans. The complication was treated successfully with broad-spectrum intravenous antibiotics and physiotherapy.

CONCLUSION

Iliac crest osteomyelitis is indeed a rare complication of appendicitis. A heightened awareness and better understanding of this complication would necessitate early diagnosis and treatment.

[Changes in epidemiology, etiology, diagnostics, and therapy of acute appendicitis]

The frequency of acute appendicitis has fallen in the last three decades in developed industrialized countries. From 1961 to 1991 the number of appendectomies performed annually in Hungary decreased significantly. Since 1991 the numbers are essentially unchanged. Appendix lumen obstruction was formerly believed to be crucial in the etiology of the illness, while today mixed aerobic, anaerobic bacterial infection is considered more important. The inflammation process - according to immunogenetic differences - may lead to recovery or tissue necrosis and perforation. To date, no methods are known that could timely distinguish spontaneously healing or conservatively treatable appendicitis from those resulting in tissue necrosis, although routine usage of abdominal ultrasound technique is added to the clinical picture's modern diagnostic arsenal. The operative method for removing the appendix also has changed. Experience has confirmed that laparoscopic appendectomy is usually more favorable in the treatment of acute appendicitis than traditional surgery.

Intra-operative culture swabs in acute appendicitis: a waste of resources

INTRODUCTION

Antibiotics gained a place in the management of acute appendicitis when the bacterial aetiology was demonstrated. Culture swabs were obtained routinely during appendicectomies to guide antibiotic use. Although current antimicrobial therapy use has become prophylactic, empirical and broad spectrum, this age-old practice still remains. Our study questions the value of this traditional practice.

MATERIALS AND METHODS

All adult and paediatric patients undergoing emergency appendicectomy over three years were retrospectively reviewed. Microbiology and appendix histology reports were retrieved. Occurrence of infective post-operative morbidity was recorded via hospital notes.

RESULTS

A total of 652 appendectomies (age 1 month to 81 years, median 20 years) were performed in a 36 month period. Four hundred and thirty-five/six hundred and fifty-two (66.7%) had intra-operative swabs taken. One hundred and forty/four hundred and thirty-five (32%) revealed presence ofa pathogens. One hundred and twenty-two/four hundred and thirty-five (28%) were sensitive to broad spectrum empirical antibiotics and only 18/435 (4.1%) cultured resistant strains. Forty-two/six-hundred and fifty-two (6.4%) patients had postoperative infective complications. Twenty-nine/forty-two (68%) had a different organism responsible for this complication. The highest proportion of positive cultures and post-operative infective complications was observed in the extremes of ages (< 10 and > 50 years) and in gangrenous appendicitis.

CONCLUSION

A majority of intra-operative swabs were negative or isolated commensal flora. Pathogens causing postoperative morbidity were frequently different from those isolated intra-operatively. None of the patients had a change of management based on the swab results. Hence routine intra-peritoneal swabs remains of little clinical value.

Identification of Bilophila wadsworthia by specific PCR which targets the taurine:pyruvate aminotransferase gene

The bile-resistant, strictly anaerobic bacterium Bilophila wadsworthia is found in human faecal flora, in human infections and in environmental samples. A specific PCR primer set for the gene encoding the first metabolic enzyme in the degradative pathway for taurine in B. wadsworthia, taurine:pyruvate aminotransferase (tpa), was developed and tested. In addition, enrichment cultures were started from faecal samples of primates and felines and shown to contain B. wadsworthia. These were subcultured on agar media and then identified by PCR fingerprinting. PCR for tpa was successful in all positive enrichment cultures and showed no amplification signal in a variety of other bacterial species. Therefore, this PCR method could be a promising tool for rapid detection of B. wadsworthia in biological samples.

Molecular detection of Campylobacter jejuni in archival cases of acute appendicitis

The role of enteric bacteria in the pathogenesis of acute appendicitis is a controversial subject. Campylobacter jejuni has been previously demonstrated in a minority of cases of acute appendicitis using microbiological or immunohistochemical methods, notably in cases where inflammation was limited to the mucosa/submucosa. Our goal was to evaluate cases of acute appendicitis for C. jejuni DNA using molecular methods, and to compare our findings to the histologic features. In total, 50 archival cases of acute appendicitis were selected, and PCR was performed using primers targeting a 286-bp fragment of the mapA gene specific to C. jejuni. Twenty histologically unremarkable appendectomy specimens served as negative controls. Cases were reviewed with attention to particular histological features including mucosal ulceration, cryptitis, depth of inflammatory infiltrate, and the presence of mural necrosis. Of acute appendicitis cases, 22% (11/50) were positive for C. jejuni DNA by PCR analysis. Control cases were negative for C. jejuni DNA. All patients presented with signs and symptoms typical of acute appendicitis. Of the C. jejuni positive cases, only 27% contained acute inflammation limited to the mucosa/submucosa, whereas the remainder had mural or transmural inflammation; therefore, the histological features of C. jejuni-positive acute appendicitis cases were indistinguishable from C. jejuni-negative cases. In summary, C. jejuni DNA was detected in a significant percentage (22%) of acute appendicitis cases, a much higher percentage than previous studies using other methodologies. As C. jejuni is an enteric pathogen that does not exist as a commensal or nonpathogenic organism, the presence of C. jejuni DNA implies current or recent infection. Further study is needed to determine whether the presence of C. jejuni DNA in acute appendicitis indicates appendiceal involvement by C. jejuni enteritis, or if there is a true causative role for C. jejuni in acute appendicitis.