Longitudinal evaluation of the cutaneous and rectal microbiota of German shepherd dogs with perianal fistulas undergoing therapy with ciclosporin and ketoconazole.

BACKGROUND: Perianal fistulas are painful ulcers or sinus tracts that disproportionately affect German shepherd dogs and are proposed as a spontaneous animal model of fistulising Crohn's disease. OBJECTIVES: To characterise the rectal and cutaneous microbiota in German shepherd dogs with perianal fistulas and to investigate longitudinal shifts with lesion resolution during immunomodulatory therapy. ANIMALS: Eleven German shepherd dogs with perianal fistulas and 15 healthy German shepherd dogs. MATERIALS AND METHODS: Affected dogs were evaluated and swabbed at three visits, 30 days apart, while undergoing treatment with ciclosporin and ketoconazole. Healthy German shepherd dogs were contemporaneously sampled. Sites included the rectum, perianal skin and axilla. The microbiome was evaluated following sequencing of the V4 hypervariable region of the 16S ribosomal RNA (rRNA) gene. RESULTS: Alpha diversity was not significantly different between healthy and affected dogs at each of the three body sites (p > 0.5), yet rectal and perianal beta diversities from affected dogs differed significantly from those of healthy dogs at Day 0 (p = 0.004). Rectal and perianal relative abundance of Prevotella spp. increased and perianal Staphylococcus spp. relative abundance decreased in affected dogs over time, coincident with lesion resolution. CONCLUSIONS AND CLINICAL RELEVANCE: Changes in lesional cutaneous and rectal microbiota occur in German shepherd dogs with perianal fistulas and shift over time with lesion resolution during immunomodulatory therapy. Further investigations of the role of cutaneous and enteric microbiota in the pathogenesis of perianal fistulas, and whether manipulation of microbial populations may ameliorate disease, are needed.

Dysbiosis in a canine model of human fistulizing Crohn's disease.

Crohn's disease (CD) is a chronic immune-mediated inflammatory condition caused by the loss of mucosal tolerance toward the commensal microbiota. On average, 29.5% and 42.7% CD patients experience perianal complications at 10 and 20 y after diagnosis, respectively. Perianal CD (pCD) result in high disease burden, diminished quality of life, and elevated health-care costs. Overall pCD are predictors of poor long-term outcomes. Animal models of gut inflammation have failed to fully recapitulate the human manifestations of fistulizing CD. Here, we evaluated dogs with spontaneous canine anal furunculosis (CAF), a disease with clinical similarities to pCD, as a surrogate model for understanding the microbial contribution of human pCD pathophysiology. By comparing the gut microbiomes between dogs suffering from CAF (CAF dogs) and healthy dogs, we show CAF-dog microbiomes are either very dissimilar (dysbiotic) or similar (healthy-like), yet unique, to healthy dog's microbiomes. Compared to healthy or healthy-like CAF microbiomes, dysbiotic CAF microbiomes showed an increased abundance of Bacteroides vulgatus and Escherichia coli and a decreased abundance of Megamonas species and Prevotella copri. Our results mirror what have been reported in previous microbiome studies of patients with CD; particularly, CAF dogs exhibited two distinct microbiome composition: dysbiotic and healthy-like, with determinant bacterial taxa such as E. coli and P. copri that overlap what it has been found on their human counterpart. Thus, our results support the use of CAF dogs as a surrogate model to advance our understanding of microbial dynamics in pCD.

Clinical, microbiological, immunological and imaging characteristics of tunnels and fistulas in hidradenitis suppurativa and Crohn's disease.

Hidradenitis suppurativa (HS) tunnels and Crohn's disease (CD) fistulas are a challenge to treat. Although pathogenic similarities have been described between HS and CD, recent studies indicate that clinical, microbiological, immunological and imaging characteristics differ between these diseases. This review highlights the differences between HS tunnels and CD fistulas. Next-generation sequencing studies demonstrate a microbiome in HS tunnels dominated by Porphyromonas spp., Prevotella spp. whereas no specific bacteria have been associated with cutaneous CD. Immunologically, TNF has been found upregulated in HS tunnels along with various interleukins (IL-8, IL-16, IL-1α and IL-1ß). In CD fistulas, Th1, Th17, IL-17, IFN-ɤ, TNF and IL-23 are increased. US imaging is an important tool in HS. US of HS tunnels depict hypoechoic band-like structure across skin layers in the dermis and/or hypodermis connected to the base of a widened hair follicle. In CD, MR imaging of simple perianal fistulas illustrates a linear, non-branching inflammatory tract relating to an internal opening in the anus or low rectum and an external opening to the skin surface. An increased awareness of the immediate potential differences between HS tunnels and CD fistulas may optimize treatment regimens of these intractable skin manifestations.

Perianal Tuberculosis: Lessons Learned in 57 Patients From 743 Samples of Histopathology and Polymerase Chain Reaction and a Systematic Review of Literature.

BACKGROUND: Few data are published on perianal tuberculosis. OBJECTIVE: This study aimed to determine the best method to diagnose tuberculosis in patients with fistula-in-ano and to conduct a systematic review to determine the incidence and characteristics of tuberculosis fistula-in-ano. DATA SOURCES: The prospective study data and existing literature were derived from PubMed, Google scholar, and Scopus STUDY SELECTION:: Prospective analysis of patients with tuberculous fistula-in-ano treated between 2014 and 2018 was conducted, and a systematic review of studies describing ≥3 patients with tuberculosis fistula-in-ano was completed. INTERVENTION: Testing of tuberculosis was performed by histopathology or polymerase chain reaction of tissue or pus from the fistula tract. MAIN OUTCOME MEASURES: The primary outcomes measured were the detection rate of various tests to detect tuberculosis in fistula-in-ano and the prevalence rate of tuberculosis in simple versus complex fistulas. RESULTS: In 637 samples (410 patients) tested, tuberculosis was detected in 49 samples (43 patients). Additional samples (n = 106) sent in patients with a high index of suspicion tested positive in 14 more patients. Thus, overall, 63 samples tested positive in 57 patients (total: 743 samples in 410 patients were tested). Tuberculosis was detected in 2 of 181 patients (1.1%) in tissue (histopathology), in 28 of 341 patients (8.2%) in tissue (polymerase chain reaction), and in 19 of 115 patients (16.5%) in pus (polymerase chain reaction) samples. To detect tuberculosis, tissue (polymerase chain reaction) was significantly better than tissue (histopathology) (28/341 vs 2/181, p < 0.00001) and pus (polymerase chain reaction) was significantly better than tissue (polymerase chain reaction) (19/115 vs 28/341, p < 0.0009). Tuberculosis was significantly more common in complex fistulas than in simple fistulas (20.3% vs 7.2%, p = 0.0002). The systematic review (n = 199) highlighted that tubercular fistulas are more common in recurrent and complex fistulas and in tuberculosis endemic regions. LIMITATIONS: The true sensitivity and specificity of each testing modality could not be determined because not all patients with tuberculosis fistula-in-ano were tested by every diagnostic modality studied. CONCLUSIONS: The tuberculosis detection rate of polymerase chain reaction was significantly higher than histopathology. Among polymerase chain reaction, pus had higher detection rate than tissue. Tuberculosis was associated with more complex and recurrent fistulas.

A Distinct Gut Microbiota Exists Within Crohn's Disease-Related Perianal Fistulae.

BACKGROUND: Gut bacteria are strongly suspected to play a key role in the pathogenesis of Crohn's disease (CD). Studies have demonstrated alterations in the gut microbiota in this patient population. The purpose of this study was to characterize the gut microbiota of fistulizing perianal CD. MATERIALS AND METHODS: Stool and fistula samples were obtained from patients undergoing surgery for CD-related anorectal fistulae. Microbial compositions of matched stool and fistula samples were characterized using 16S rRNA gene profiling. The effect of sample type, patient gender, disease classification (Montreal A/B), disease activity (Harvey Bradshaw Index), antibiotic use, and presence of active proctitis on microbial composition was assessed. RESULTS: Samples were obtained from 18 patients. Bacteroides was the most abundant genera across all samples collected, followed by Streptococcus and Bifidobacterium. Bifidobacterium was present at significantly higher levels in fecal samples than fistula samples, whereas Achromobacter and Corynebacterium were present at significantly higher levels in fistula samples. Antibiotic, but not thiopurine or antitumor necrosis factor medication, exposure affected the gut microbial composition. Patient gender, disease classification, disease activity, and presence of active proctitis did not alter stool or fistula microbiota. CONCLUSIONS: Our data show that the gut microbiota within CD-related anorectal fistulae is distinct from that in stool samples obtained from the same patients. We also observe a dysbiosis in patients treated with antibiotics compared with those not treated with antibiotics.

[Perianal abscess after anal intercourse should raise suspicion of rectal gonorrhoeae infection].

Neisseria gonorrhoeae infection is a sexually transmitted disease. Rectal gonorrhoea is often asymptomatic, the most common symptoms are anal pain, bleeding and purulent discharge. This case report describes a younger man, who experienced increasing anal pain and later fever after anal intercourse. N. gonorrhoeae infection was verified, before a clinical examination revealed a perianal abscess. During incision of the abscess an anal fistula was suspected, and six weeks after primary surgery and treatment with relevant antibiotics, transanal ultrasonography showed perianal scarring and no signs of anocutaneous fistula.

Pathogenesis and persistence of cryptoglandular anal fistula: a systematic review.

Anal fistulas continue to be a problem for patients and surgeons alike despite scientific advances. While patient and anatomical characteristics are important to surgeons who are evaluating patients with anal fistulas, their development and persistence likely involves a multifaceted interaction of histological, microbiological, and molecular factors. Histological studies have shown that anal fistulas are variably epithelialized and are surrounded by dense collagen tissue with pockets of inflammatory cells. Yet, it remains unknown if or how histological differences impact fistula healing. The presence of a perianal abscess that contains gut flora commonly leads to the development of anal fistula. This implies a microbiological component, but bacteria are infrequently found in chronic fistulas. Recent work has shown an increased expression of proinflammatory cytokines and epithelial to mesenchymal cell transition in both cryptoglandular and Crohn's perianal fistulas. This suggests that molecular mechanisms may also play a role in both fistula development and persistence. The aim of this study was to examine the histological, microbiological, molecular, and host factors that contribute to the development and persistence of anal fistulas.

Comparison of histopathology and real-time polymerase chain reaction (RT-PCR) for detection of Mycobacterium tuberculosis in fistula-in-ano.

PURPOSE: Histopathology is commonly used to diagnose tuberculosis in fistula-in-ano. The aim was to compare the sensitivity of polymerase chain reaction and histopathology in detecting tuberculosis in fistula-in-ano. METHODS: The histopathology and polymerase chain-reaction of tissue (fistula tract) was done in all the consecutive operated cases. When pus sample was also available, polymerase chain reaction-pus was also done RESULTS: Three hundred forty seven samples (179 patients) were tested over 2 years (median 6.5 months). The mean age was 38.8 ± 10.7 years, and male/female was 170/9. Histopathology and polymerase chain reaction of tissue (fistula tract) was done in 152 and 165 patients, respectively. Polymerase chain reaction (pus) could be done in 30 patients. Overall, tuberculosis was detected in 20/179 (11.2%) patients. Of these, tuberculosis was detected by histopathology (tissue) in 1/152 (0.7%) and by polymerase chain reaction (tissue) in 14/165 (8.5%) patients. In pus, polymerase chain reaction detected tuberculosis in 6/30 (20%) patients. Both polymerase chain reaction of tissue and pus were positive in one patient. Polymerase chain reaction (tissue) and polymerase chain reaction (pus) were significantly more sensitive than histopathology (tissue) for detecting tuberculosis [histopathology 1/152 vs. polymerase chain reaction (tissue) 14/165, p = 0.0009] [histopathology 1/152 vs. polymerase chain reaction (pus) 6/30, p < 0.0001]. In 20 patients detected to have tuberculosis, four drug anti-tubercular therapy was recommended for 6 months. The therapy was completed in 13 patients and 12/13 (92.3%) were cured. The therapy is continuing in 3/20 patients. Four patients did not take the therapy. None of them was cured. CONCLUSIONS: Polymerase chain reaction was significantly more sensitive than histopathology in detecting tuberculosis in fistula-in-ano. Histopathology might be missing out tuberculosis in many patients leading to recurrence of the fistula.

[Perianal infection in patients with hemoblastosis: Risk factors and possibilities of prevention]. / Perianal'naya infektsiya u bol'nykh gemoblastozami: faktory riska i vozmozhnosti profilaktiki.

AIM: to identify poor prognostic factors for perianal infection (PI) in patients with hemoblastosis and to define an effective tactic for preventive and therapeutic measures. SUBJECTS AND METHODS: The prospective study enrolled 72 patients (37 men and 35 women; mean age, 47 years) with hemoblastosis that was complicated by the development of one of the following forms of PI: abscess, infiltrate, multiple ulcers. Different clinical and laboratory characteristics of the patients were examined to identify risk factors for PI. The species-specific concordance of microorganisms isolated from the anus and blood in the development of PI was assessed to record the latter as a source of sepsis. Treatment policy was defined according to the clinical form of PI. RESULTS: Acute myeloid leukemias and lymphomas were the most common background diseases in 30 (41.7%) and 22 (30.6%) patients, respectively. During induction chemotherapy cycles, perianal tissue infection occurred twice more frequently (66%) than totally at the onset of hemoblastosis (13%) and after achievement of remission (during consolidation and maintenance therapy) (21%; Fisher's exact test; p=0.01). PI in agranulocytosis was more than twice as common as in its absence: 69.4% vs 30.6% (p=0.01) and was responsible for sepsis in 9 (18%) of 50 patients. The main source of perianal tissue infection in patients with granulocytopenia was anal fissures and fistulas and ulcers of the anal canal: 44 (88%) cases of the 50 cases. In PI as an abscess, the average white blood cell count was 5 times higher (p=0.01) than that in PI as an infiltrate (or multiple ulcers): 6.6·109/l and 1.2·109 g/l. Abscess formation was observed in 16 (22.2%) patients and an indication for surgical drain. The inflammatory infiltrate was found to develop in 48 (66.7%) patients; multiple ulcers were seen in 8 (11.1%); in this group, parenteral antimicrobial therapy proved to be effective in 36 (78%) patients. 29 patients were operated on for anal fissures and fistulas at intercycle intervals. After continuing CT, PI recurrences were observed in 4 (9.1%) patients. In the operated versus medically treated patients, the risk of complications associated with abnormalities in the perianal area during continued CT was 5 times statistically significantly lower (odds ratio=0.2; 95% confidence interval 0.1 to 0.5; p=0.04; Cochran-Mantel test). CONCLUSION: Induction CT cycles, the status of granulocytopenia, and the presence of infection sources in the anal canal as an anal fissure, skin ulcerations, or a fistula should be considered as independent statistically significant prognostic risk factors for PI. The number of granulocytes determines the form of inflammation, the course of infection, and the chance of developing sepsis. The effective prevention encompassing surgical treatment for anal canal diseases reduces the risk of septic complications and the number of paraproctitis recurrences, contributing to the implementation of a planned CT program in patients with hemoblastosis.

CT of acute perianal abscesses and infected fistulae: a pictorial essay.

Computed tomography (CT) is an effective, readily available diagnostic imaging tool for evaluation of the emergency room (ER) patients with the clinical suspicion of perianal abscess and/or infected fistulous tract (anorectal sepsis). These patients usually present with perineal pain, fever, and leukocytosis. The diagnosis can be easy if the fistulous tract or abscess is visible on inspection of the perianal skin. If the tract or abscess is deep, then the clinical diagnosis can be difficult. Also, the presence of complex tracts or supralevator extension of the infection cannot be judged by external examination alone. Magnetic resonance imaging (MRI) is the best imaging test to accurately detect fistulous tracts, especially when they are complex (Omally et al. in AJR 199:W43-W53, 2012). However, in the acute setting in the ER, this imaging modality is not always immediately available. Endorectal ultrasound has also been used to identify perianal abscesses, but this modality requires hands-on expertise and can have difficulty localizing the offending fistulous tract. It may also require the use of a rectal probe, which the patient may not be able to tolerate. Contrast-enhanced CT is a very useful tool to diagnose anorectal sepsis; however, this has not received much attention in the recent literature (Yousem et al. in Radiology 167(2):331-334, 1988) aside from a paper describing CT imaging following fistulography (Liang et al. in Clin Imaging 37(6):1069-1076, 2013). An infected fistula is indicated by a fluid-/air-filled soft tissue tract surrounded by inflammation. A well-defined round to oval-shaped fluid/air collection is indicative of an abscess. The purpose of this article is to demonstrate the usefulness of contrast-enhanced CT in the diagnosis of acute anorectal sepsis in the ER setting. We will discuss the CT appearance of infected fistulous tracts and abscesses and how CT imaging can guide the ER physician in the clinical management of these patients.

What role do bacteria play in persisting fistula formation in idiopathic and Crohn's anal fistula?

AIM: The aetiology of Crohn's disease-related anal fistula remains obscure. Microbiological, genetic and immunological factors are thought to play a role but are not well understood. The microbiota within anal fistula tracts has never been examined using molecular techniques. The present study aimed to characterize the microbiota in the tracts of patients with Crohn's and idiopathic anal fistula. METHOD: Samples from the fistula tract and rectum of patients with Crohn's and idiopathic anal fistula were analysed using fluorescent in situ hybridization, Gram staining and scanning electron microscopy were performed to identify and quantify the bacteria present. RESULTS: Fifty-one patients, including 20 with Crohn's anal fistula, 18 with idiopathic anal fistula and 13 with luminal Crohn's disease and no anal fistula, were recruited. Bacteria were not found in close association with the luminal surface of any of the anal fistula tracts. CONCLUSION: Anal fistula tracts generally do not harbour high levels of mucosa-associated microbiota. Crohn's anal fistulas do not seem to harbour specific bacteria. Alternative explanations for the persistence of anal fistula are needed.

Acute diarrhea and metabolic acidosis caused by tuberculous vesico-rectal fistula.

Acquired vesico-rectal fistula is an uncommon complication of pelvic malignant tumors, surgical injury, inflammatory disorders such as tuberculosis infection, radiotherapy and less commonly diverticulum of the urinary tract. The fistula is often identified by urinary tract abnormalities such as dysuria, recurrent urinary tract infection, pneumaturia, and fecaluria. Here, we report an unusual case of a patient with a vesico-rectal fistula of tuberculous origin, presenting with severe acute diarrhea, metabolic acidosis, hyperchloremia and hypokalemia while with only mild urinary tract symptoms. The patient was cured by tuberculostatic therapy.

Clinical and microbiological characteristics of perianal infections in adult patients with acute leukemia.

BACKGROUND: Perianal infection is a common problem for patients with acute leukemia. However, neutropenia and bleeding tendency are relatively contraindicated to surgical intervention. The epidemiology, microbiology, clinical manifestations and outcomes of perianal infection in leukemic patients are also rarely discussed. METHOD: The medical records of 1102 adult patients with acute leukemia at a tertiary medical center in Taiwan between 2001 and 2010 were retrospectively reviewed and analyzed. RESULT: The prevalence of perianal infection was 6.7% (74 of 1102) in adult patients with acute leukemia. Twenty-three (31%) of the 74 patients had recurrent episodes of perianal infections. Patients with acute myeloid leukemia had higher recurrent rates than acute lymphoblastic leukemia patients (p = 0.028). More than half (n = 61, 53%) of the perianal infections were caused by gram-negative bacilli, followed by gram-positive cocci (n = 36, 31%), anaerobes (n = 18, 15%) and Candida (n = 1, 1%) from pus culture. Eighteen patients experienced bacteremia (n = 24) or candidemia (n = 1). Overall 41 (68%) of 60 patients had polymicrobial infection. Escherichia coli (25%) was the most common micro-organism isolated, followed by Enterococcus species (22%), Klebsiella pneumoniae (13%), and Bacteroides species (11%). Twenty-five (34%) of 74 patients received surgical intervention. Acute leukemia patients with surgically managed anal fistulas tended to have fewer recurrences (p = 0.067). Four (5%) patients died within 30 days after diagnosis of perianal infection. Univariate analysis of 30-day survival revealed the elderly (≧ 65 years) (p = 0.015) and patients with shock (p<0.001) had worse outcome. Multivariate analysis showed septic shock to be the independent predictive factor of 30-day crude mortality of perianal infections (p = 0.016). CONCLUSION: Perianal infections were common and had high recurrence rate in adult patients with acute leukemia. Empirical broad-spectrum antibiotics with anaerobic coverage should be considered. Shock independently predicted 30-day crude mortality. Surgical intervention for perianal infection remains challenging in patients with acute leukemia.

Assessment of microbiota and peptidoglycan in perianal fistulas.

Transanal advancement flap repair has been advocated as the treatment of choice for high transsphincteric perianal fistulas, but fails in 1 of every 3 patients. Persistence of the fistula after flap repair might be the result of ongoing disease in the remaining fistula tract. In 10 specimens of the distal part of the fistula, microbiota was assessed by means of conventional microbiological culture and 16S rRNA gene sequencing. Proinflammatory bacterial peptidoglycan and recognition proteins were assessed by immunohistochemistry. Bacterial species were bowel derived, skin derived, or a combination of both. No mycobacterium species were identified. 16S rRNA gene sequencing failed to identify bacteria in all but 1 specimen, most likely as a result of low numbers of organisms. Peptidoglycan was detected in 90% of the patients, and a host response to peptidoglycan in 60%. Therefore, we suggest that peptidoglycan might play a role in the ongoing inflammation in perianal fistulas.

Perianal abscess and fistula-in-ano in children: clinical characteristic, management and outcome.

PURPOSE: The aims of this study are to evaluate the clinical characteristics of perianal abscess and fistula-in-ano in children, and to assess our experience in treatment, and to identify factors that affected the clinical outcomes. METHODS: A retrospective review of children with perianal abscess and fistula-in-ano was carried out in a tertiary care children's hospital from January 2005 to December 2010. Demographic information of the patients, localization of the lesions, treatment procedures, microbial organisms in pus, usage of antibiotics, abscess recurrence, development of fistula-in-ano, and duration of symptoms were recorded. Patients with systemic diseases and inflammatory bowel diseases were excluded from the study. RESULTS: A total of 158 children (146 males, 12 females) treated for perianal abscess and fistula-in-ano with a median age of 7.2 months (ranging 16 days to 18 years) were eligible for the study. Initial examination of the 136 patients revealed perianal abscess and 22 patients with fistula-in-ano. Primary treatment was incision and drainage (I/D) for the fluctuating perianal abscess (73.5%), and local care for the spontaneously (S/D) drained abscess (26.5%) with or without antibiotic therapy. Patients were divided into two groups according to age distribution, 98 of the patients were younger than 12 months, and 60 were older than 12 months of age. There was no significant difference in sex distribution, localization of the lesions, treatment procedures, recurrence of abscess and fistula-in-ano formation between the two age groups (p > 0.05). Recurrence rates (27% in I/D and 30.6% in S/D, p > 0.05) and development of fistula-in-ano (20% in I/D and 27.8 in S/D, p > 0.05) were not significant I/D and S/D groups. Kind of the microorganisms in pus swaps did not effect the fistula-in-ano formation. Usage of antibiotics significantly reduced the development of fistula-in-ano (p = 0.001), but did not effect the recurrence of perianal abscess (p > 0.05). The mean follow-up period was 10.6 ± 8.6 months. While the 9 of the overall 52 fistula-in-ano (22 initial, 30 after abscess treatment) were resolved spontaneously, 43 of the remaining needed surgical intervention (fistulotomy/fistulectomy). CONCLUSIONS: Although management of perianal abscess is still controversial, simple drainage of the perianal abscess with additional antibiotic therapy reduces the development of fistula-in-ano. Fistula-in-ano within children has a chance of spontaneous resolution thus the immediate surgical intervention should be avoided.