Clinical and microbiological analysis of adult perianal abscess

Causal relationship between body mass index and anal fistula: a two-sample Mendelian randomization study

Background

Significant evidence has been documented regarding the intricate connection between the development of anal fistula (AF) and the composition of Body Mass Index (BMI). Nevertheless, due to the inherent limitations of reverse causality and confounders inherent in observational studies, this relationship remains unclarified. Our study aims to reveal the causal impact between BMI and AF, as well as identify its associated risk factors, thereby providing a more comprehensive understanding of this complex interaction.

Methods

Single nucleotide polymorphisms (SNPs) identified through genome-wide association study (GWAS) databases were used as instrumental variables for analysis. BMI served as the exposure variable, with six pooled GWAS datasets included. AF was the outcome variable. The Inverse Variance Weighted (IVW) method was used as the primary analytical technique, with MR-Egger regression, Weighted Median (WME) estimation, and Multiplicity Residual Sum and Outlier (MR-PRESSO) tests serving as secondary validations of the IVW results. Odds ratios (OR) were utilized as indicators to evaluate the causal relationship between BMI and AF.

Results

A total of 738 SNPs strongly associated with the exposure were identified as instrumental variables. The IVW results demonstrated a positive correlation between BMI and the risk of AF. The MR-Egger analysis yielded p-values greater than 0.05, indicating no pleiotropic effects among the selected SNPs. Cochran's Q test also resulted in p-values greater than 0.05, suggesting no significant heterogeneity among the instrumental variables. The MR-PRESSO analysis revealed no horizontal pleiotropy or outliers potentially violating the causal assumption (p > 0.05).

Conclusion

High BMI is positively associated with the risk of AF, and correcting BMI levels may have a preventive effect on the incidence of AF.

Causal relationship between obesity and anorectal abscess: a Mendelian randomization study

Background

Observational studies have indicated that obesity is a risk factor for anorectal abscess (ARB). However, it remains unclear whether a causal genetic relationship exists between obesity and ARB.

Methods

Univariate and multivariate Mendelian randomization (MR) were conducted using data from a large, published genome-wide association study (GWAS) of European ancestry to infer a causal relationship between obesity and ARB. Inverse variance weighted (IVW) analysis served as the primary analysis method, with results reported as odds ratios (OR).

Results

MR analysis revealed that body mass index (BMI) positively affects ARB (OR 1.974, 95% confidence interval (CI) 1.548-2.519, p = 4.34 × 10-8). The weighted median method (OR = 1.879, 95% CI 1.248-2.829, p = 0.002) and Bayesian model averaging (BMA) (OR = 1.88, 95% CI 1.477-2.392, p = 2.85 × 10-7) also demonstrated consistent results. Subsequently, the impact of several obesity-related characteristics on ARB was assessed. Body fat percentage (BF), whole body fat mass (FM), waist circumference (WC), and hip circumference (HC) were found to be causally associated with an increased risk of ARB. However, these associations vanished after adjusting for BMI effects.

Conclusion

The study confirms a positive causal effect of obesity on ARB, highlighting that reasonable weight control is an important strategy to reduce the incidence of ARB.

Natural Products with Potential Effects on Hemorrhoids: A Review

Hemorrhoid disease is a common anorectal disorder affecting populations worldwide, with high prevalence, treatment difficulties, and considerable treatment costs. Compared to other treatment options, medical therapy for hemorrhoids offers minimal harm, more dignity to patients, and is more economical. Unfortunately, there are few chemical hemorrhoid medications available clinically, which makes the search for efficacious, cost-effective, and environmentally friendly new medication classes a focal point of research. In this context, searching for available natural products to improve hemorrhoids exhibits tremendous potential. These products are derived from nature, predominantly from plants, with a minor portion coming from animals, fungi, and algae. They have excellent coagulation pathway regulation, anti-inflammatory, antibacterial, and tissue regeneration activities. Therefore, we take the view that they are a class of potential hemorrhoid drugs, prevention products, and medication add-on ingredients. This article first reviews the factors contributing to the development of hemorrhoids, types, primary symptoms, and the mechanisms of natural products for hemorrhoids. Building on this foundation, we screened natural products with potential hemorrhoid improvement activity, including polyphenols and flavonoids, terpenes, polysaccharides, and other types.

Does microbiology of perianal abscesses affect the length of hospital stay?

BACKGROUND

Perianal abscess is a common disease among adults, necessitating surgical drainage. We aimed to assess the role of microbiology and other factors in prolonged hospitalization of patients with perianal abscesses.

METHODS

This retrospective study included all patients aged 18 or older who underwent surgical incision and drainage for perianal abscess in a single medical center between 2016 and 2020. Data regarding demographics, bacteriological cultures, and length of hospital stay were collected via electronic patient charts. A prolonged hospital stay was defined as a LOS longer than 3 days.

RESULTS

A total of 791 patients were included, of which 77.5% were male, with a mean age of 43.2. Overall, 46.1% of patients had positive cultures, of which 69.9% were polymicrobial. The most common pathogen found in obtained cultures was Escherichia coli (69.9%), followed by streptococcus species (36.7%) and Bacteroides (26.0%). Females had a significantly longer hospital stay (p = 0.03). Prolonged hospital stay was associated with older age (p < 0.0001), female gender (p = 0.04), and positive cultures for Enterococcus (p = 0.02).

CONCLUSIONS

This study identified clinical and microbiological risk factors for prolonged hospitalization in patients with perianal abscesses. Further studies are needed to evaluate the association between specific pathogens and rates of complications.

Microbiota in adult perianal abscess revealed by metagenomic next-generation sequencing

The microbiota of perianal abscesses is scarcely investigated. Identifying causative bacteria is essential to develop antibiotic therapy. However, culture-based methods and molecular diagnostics through 16S PCR technology are often hampered by the polymicrobial nature of perianal abscesses. We sought to characterize the microbiota composition of perianal abscesses via metagenomic next-generation sequencing (mNGS). Fourteen patients suffering from perianal abscesses between March 2023 and August 2023 underwent retrospective assessment. Information from medical records was used, including clinical information, laboratory data, and culture and mNGS results. Forty bacterial taxa were identified from perianal abscesses through mNGS, with Bilophila wadsworthia (71.4%), Bacteroides fragilis (57.1%), and Escherichia coli (50.0%) representing the most prevalent species. mNGS identified an increased number of bacterial taxa, with an average of 6.1 compared to a traditional culture-based method which only detected an average of 1.1 in culture-positive perianal abscess patients, predominantly E. coli (75.0%), revealing the polymicrobial nature of perianal abscesses. Our study demonstrates that a more diverse bacterial profile is detected by mNGS in perianal abscesses, and that Bilophila wadsworthia is the most prevalent microorganism, potentially serving as a potential biomarker for perianal abscess.IMPORTANCEAccurately, identifying the bacteria causing perianal abscesses is crucial for effective antibiotic therapy. However, traditional culture-based methods and 16S PCR technology often struggle with the polymicrobial nature of these abscesses. This study employed metagenomic next-generation sequencing (mNGS) to comprehensively analyze the microbiota composition. Results revealed 40 bacterial taxa, with Bilophila wadsworthia (71.4%), Bacteroides fragilis (57.1%), and Escherichia coli (50.0%) being the most prevalent species. Compared to the culture-based approach, mNGS detected a significantly higher number of bacterial taxa (average 6.1 vs 1.1), highlighting the complex nature of perianal abscesses. Notably, Bilophila wadsworthia emerged as a potential biomarker for these abscesses. This research emphasizes the importance of mNGS in understanding perianal abscesses and suggests its potential for improving diagnostic accuracy and guiding targeted antibiotic therapy in the future.

Restricted cubic spline model analysis of the association between anal fistula and anorectal abscess incidence and body mass index

Objective

The epidemiological profile of anal fistula and anorectal abscess has not been well studied. Based on the results of a retrospective cross-sectional survey, we aimed to investigate the potential influential factors associated with anal fistula and anorectal abscess.

Methods

We conducted a retrospective analysis of outpatients who visited the proctology department at China-Japan Friendship Hospital between January 2017 and May 2022. A comprehensive questionnaire was designed to collect potential influential factors, and according to formal anorectal examination and the corresponding diagnostic criteria, all the participants were divided into patients with anal fistula or perianal abscess and healthy control group. Multiple logistic regression was used to identify factors in significant association with anal fistula and perianal abscess. Additionally, we combined restricted cubic spline regression to examine the dose-response relationship between factors and the risk of developing anal fistula or anorectal abscess.

Results

The present study included 1,223 participants, including 1,018 males and 206 females, with 275 anal fistulas, 184 anorectal abscesses, and 765 healthy controls. We found no statistically significant differences between patients and controls in basic information and preoperative assessment of life factors, except for body mass index. It was indicated that people with overweight or obesity were more prone to anal fistula (OR overweight = 1.35, 95% CI: 1.00-1.82, P = 0.047; OR obesity = 3.44, 95% CI: 2.26-5.26, P < 0.001) or anorectal abscess (OR overweight = 1.41, 95% CI: 1.00-1.99, P = 0.05; OR obesity: 2.24, 95% CI: 1.37-3.67, P = 0.001) than normal-weight individuals. The dose-response research indicated the J-shaped trend between the ascending BMI levels and the higher risk of suffering from anal fistula and anorectal abscess.

Conclusions

Our findings indicate that overweight and obesity are risk factors for anal fistula and anorectal abscess, which plays a role in the prevention of anorectal diseases. This provides some theoretical basis for clinicians to provide health education to their patients.

Bacteriophages and Their Host Range in Multidrug-Resistant Bacterial Disease Treatment

The rapid emergence of multidrug-resistant (MDR) bacteria in recent times has prompted the search for new and more potent antibiotics. Bacteriophages (commonly known as phages) are viruses that target and infect their bacterial hosts. As such, they are also a potential alternative to antibiotics. These phages can be broadly categorized into monovalent (with a narrow host range spectrum and specific to a single bacterial genus) and polyvalent (with a broad host range and specific to more than two genera). However, there is still much ambiguity in the use of these terms, with researchers often describing their phages differently. There is considerable research on the use of both narrow- and broad-host range phages in the treatment of infections and diseases caused by MDR bacteria, including tuberculosis, cystic fibrosis, and carbapenem-resistant Enterobacterales (CRE) infectious diseases. From this, it is clear that the host range of these phages plays a vital role in determining the effectiveness of any phage therapy, and this factor is usually analyzed based on the advantages and limitations of different host ranges. There have also been efforts to expand phage host ranges via phage cocktail development, phage engineering and combination therapies, in line with current technological advancements. This literature review aims to provide a more in-depth understanding of the role of phage host ranges in the effectiveness of treating MDR-bacterial diseases, by exploring the following: phage biology, the importance of phages in MDR bacteria diseases treatment, the importance of phage host range and its advantages and limitations, current findings and recent developments, and finally, possible future directions for wide host range phages.

New Perianal Sepsis Risk Score Predicts Outcome of Elderly Patients with Perianal Abscesses

Antibiotic therapy following surgical perianal abscess drainage is debated, but may be necessary for high-risk patients. Frailty has been shown to increase the risk of unfavorable outcomes in elderly surgical patients. This study aims to identify high-risk patients by retrospectively analyzing a single-center cohort and using a pretherapeutic score to predict the need for postoperative antibiotics and extended nursing care following perianal abscess drainage surgery. The perianal sepsis risk score was developed through univariable and multivariable analysis. Internal validation was assessed using the area under receiver-operating characteristic curve. Elderly, especially frail patients exhibited more severe perianal disease, higher frequency of antibiotic therapy, longer hospitalization, poorer clinical outcomes. Multivariable analysis revealed that scores in the 5-item modified frailty index, severity of local infection, and preoperative laboratory markers of infection independently predicted the need for prolonged hospitalization and anti-infective therapy after abscess drainage surgery. These factors were combined into the perianal sepsis risk score, which demonstrated better predictive accuracy for prolonged hospitalization and antibiotic therapy compared with chronological age or frailty status alone. Geriatric assessments are becoming increasingly important in clinical practice. The perianal sepsis risk score identifies high-risk patients before surgery, enabling early initiation of antibiotic therapy and allocation of additional nursing resources.

Disease- and Medication-Specific Differences of the Microbial Spectrum in Perianal Fistulizing Crohn's Disease-Relevant Aspects for Antibiotic Therapy

Perianal fistulizing Crohn's Disease (CD) with abscess formation represents an aggressive phenotype in Inflammatory Bowel Disease (IBD) with increased morbidity. Treatment is multidisciplinary and includes antibiotics, but knowledge about the microbial spectrum is rare often resulting in inadequate antimicrobial therapy. In this single center retrospective study, all patients who were operated due to perianal abscess formation were retrospectively analyzed and the microbial spectrum evaluated. Patients were divided into a CD and non-CD group with further subgroup analysis. 138 patients were finally included in the analysis with 62 patients suffering from CD. Relevant differences were detected for the microbial spectrum with anaerobic bacteria being significantly more often isolated from non-CD patients. In a subgroup-analysis of CD patients only, medical therapy had a relevant effect on the microbial spectrum since Streptococcus groups and Enterobacterales were significantly more often isolated in patients treated with steroids compared to those being treated by antibodies. In conclusion, the microbial spectrum of patients suffering from CD varies significantly from non-CD patients and immunosuppressive medication has a relevant effect on isolated pathogens. Based on that, adaption of antibiotic treatment might be discussed in the future.

Drug resistant bacteria in perianal abscesses are frequent and relevant

Perianal abscesses are frequent diseases in general surgery. Principles of standard patient care are surgical drainage with exploration and concomitant treatment of fistula. Antiinfective therapy is frequently applied in cases of severe local disease and perianal sepsis. However, the role of microbiologic testing of purulence from perianal abscesses is disputed and the knowledge concerning bacteriology and bacterial resistances is very limited. A retrospective cohort study was performed of consecutive patients (≥ 12 years of age) from a tertiary care hospital, who underwent surgical treatment for perianal abscess from 01/2008 to 12/2019. Subdividing the cohort into three groups regarding microbiological testing results: no microbiological testing of purulence (No_Swab, n = 456), no detection of drug resistant bacteria [DR(−), n = 141] or detection of bacteria with acquired drug resistances from purulence [DR(+), n = 220]. Group comparisons were performed using Kruskall–Wallis test and, if applicable, followed by Dunn´s multiple comparisons test for continuous variables or Fishers exact or Pearson’s X² test for categorical data. Fistula persistence was estimated by Kaplan Meier and compared between the groups using Log rank test. Corralation analysis between perioperative outcome parameters and bacteriology was performed using Spearman´s rho rank correlation. Higher pretherapeutic C-reactive protein (p < 0.0001) and white blood cell count (p < 0.0001), higher rates of supralevatoric or pararectal abscesses (p = 0.0062) and of complicated fistula-in-ano requiring drainage procedure during index surgery (p < 0.0001) reflect more severe diseases in DR(+) patients. The necessity of antibiotic therapy (p < 0.0001), change of antibiotic regimen upon microbiologic testing results (p = 0.0001) and the rate of re-debridements during short-term follow-up (p = 0.0001) were the highest, the duration until definitive fistula repair was the longest in DR(+) patients (p = 0.0061). Escherichia coli, Bacteroides, Streptococcus and Staphylococcus species with acquired drug resistances were detected frequently. High rates of resistances against everyday antibiotics, including perioperative antibiotic prophylaxis were alarming. In conclusion, the knowledge about individual bacteriology is relevant in cases of complex and severe local disease, including locally advanced infection with extended soft tissue affection and perianal sepsis, signs of systemic inflammatory response as well as the need of re-do surgery for local debridements during short-term and fistula repair during long-term follow-up. Higher rates of acquired antibiotic resistances are to be expected in patients with more severe diseases.

Multiple Secondary Healthcare-Associated Infections Due to Carbapenem-Resistant Organisms in a Critically Ill COVID-19 Patient on Extensively Prolonged Venovenous Extracorporeal Membrane Oxygenation Support-A Case Report

Patients with severe Coronavirus disease 2019 (COVID-19) are at high risk for secondary infection with multidrug-resistant organisms (MDROs). Secondary infections contribute to a more severe clinical course and longer intensive care unit (ICU) stays in patients with COVID-19. A man in his 60s was admitted to the ICU at a university hospital for severe COVID-19 pneumonia requiring mechanical ventilation. His respiratory condition worsened further due to persistent bacteremia caused by imipenem-non-susceptible Klebsiella aerogenes and he required VV-ECMO. Subsequently, he developed a catheter-related bloodstream infection (CRBSI) due to Candida albicans, ventilator-associated pneumonia (VAP) due to multidrug-resistant Pseudomonas aeruginosa (MDRP), and a perianal abscess due to carbapenem-resistant K. aerogenes despite infection control procedures that maximized contact precautions and the absence of MDRO contamination in the patient’s room environment. He was decannulated from VV-ECMO after a total of 72 days of ECMO support, and was eventually weaned off ventilator support and discharged from the ICU on day 138. This case highlights the challenges of preventing, diagnosing, and treating multidrug-resistant organisms and healthcare-associated infections (HAIs) in the critical care management of severe COVID-19. In addition to the stringent implementation of infection prevention measures, a high index of suspicion and a careful evaluation of HAIs are required in such patients.

Treatments for the amelioration of persistent factors in complex anal fistula

Anal fistulae are abnormal hollow connections between the wall of the anal canal and the perianal skin around the anus that have remained a burden on the medical sector for centuries. The complexity of this disease is attributed to a number of factors such as the degree of associated sphincter muscle, concomitant illnesses, existence of multiple fistulous tracts and the number of previous interventions. Persistence of a complex anal fistula can cause a decline in patient's physical quality of life as well as impact on the psychological status of patients who often suffer from anxiety and depression. Surgical intervention remains the gold standard for treatment, however; the risk of incontinence and high recurrence potential has led to interest into developing alternative treatment approaches such as the use of biologics, bioactives and biomaterials. One potential reason for these varied outcomes could be the multifactorial interplay between genetic, immune-related, environmental, and microbial persistence factors on tissue regeneration. Recent observations have proposed that adverse inflammatory mediators may contribute more than microbial factors. The moderate to high success rates of biotechnological advances (mesenchymal stem cells and biomaterial scaffolds) show promise as therapies for the amelioration of adverse persistent factors while facilitating a means to closing the fistula tract. The purpose of this review is to outline recent advances in biologics and combination therapies to treat persistent factors associated with complex anal fistula.

Coinfection of Clostridium perfringens and Escherichia coli in gas-producing perianal abscess diagnosed by 16S rDNA sequencing: a case report

BACKGROUND

Gas-producing perianal abscess raises the possibility of clostridial infection, with Clostridium perfringens being the most common causative agent, which is highly lethal if untreated timely. As the treatment of clostridial infections often differs from that of non-clostridial infections, which they may closely resemble, the importance of accurate pathogenic organism identification cannot be overemphasized. The 16S rDNA of bacteria is highly conserved within a species and among species of the same genus but demonstrates substantial variation between different species, thus making it a suitable genomic candidate for bacterial detection and identification.

CASE PRESENTATION

Here, we report the case of a 53-year-old patient who was admitted to the hospital for a gas-producing perianal abscess. The patient was managed with ceftizoxime and ornidazole and then received debridement and drainage at the lesion on the second day after admission. The bacterial cultures of the patient isolates from the debridement showed a coinfection of Escherichia coli and Enterococcus faecium. Although perianal redness and swelling subsided obviously after the surgery, the patient was febrile to 38.3℃ with his left upper thigh red and swollen, aggravated with tenderness and crepitus. Considering insufficient debridement and the risk of incorrect identification of pathogens, a second debridement and drainage were performed 4 days after the primary operation, and 16S rDNA sequencing of the isolates implicated Clostridium perfringens infection. Given the discrepancies in diagnostic results and the treatment outcomes, Enterococcus faecium was identified as sample contamination, and a diagnosis of coinfection of Clostridium perfringens and Escherichia coli in gas-producing perianal abscess was confirmed. The patient was then successfully treated with meropenem and vancomycin and was discharged at 27 days of admission.

CONCLUSIONS

This case represents the first report of coinfection of both clostridial and non-clostridial organisms in gas-producing perianal abscess and the first case reporting the use of 16S rDNA sequencing in the diagnosis of perianal abscess. Timely pathogen identification is critical for treating gas-producing perianal abscess and an antibiotic regimen covering both aerobic and anaerobic organisms is recommended before true pathogens are identified.

Occurrence and characterization of hyperviscous K1 and K2 serotype in Klebsiella pneumoniae

BACKGROUND:

Klebsiella pneumoniae causes both nosocomial and community-associated infections. Hypervirulent K. pneumoniae (hvKP), new variant of K. pneumoniae, can cause invasive infections in young healthy individuals as well as in the immunocompromised population. Hypervirulent strains frequently belong to capsular serotypes K1 or K2. Emergence of antimicrobial resistance in hvKP is a cause for concern.

AIM AND OBJECTIVE:

The present study was done to detect the K1 and K2 serotypes among clinical isolates of K. pneumoniae, spectrum of infections caused by them and presence of common beta-lactamases encoding genes in them.

MATERIALS AND METHODS:

A total of 370 isolates of K. pneumoniae, isolated from various clinical samples over a period of 1 year was included in this study. Antibiotic susceptibility testing to various classes of antimicrobials was done as per Clinical and Laboratory Standard Institute guidelines. The presence of K2A (specific to serotype K2), magA (specific to serotype K1), and rmpA genes was detected by multiplex polymerase chain reaction (PCR). Extended-spectrum beta-lactamases (TEM, SHV, and CTX-M), plasmid-mediated AmpCs (MOX, CIT, DHA, ACC, EBC, and FOX), and carbapenemase genes (IMP, VIM, NDM, KPC, and OXA-48) were also determined by PCR.

RESULTS:

Among the 370 isolates, 8 harbored K2A gene and one harbored magA. rmpA gene was detected in three isolates along with K1 or K2 serotypes. Seven K2A-positive isolates were resistant to one or more classes of antimicrobials. The studied ESBL genes were present in four isolates. Two isolates harbored carbapenemase genes (NDM-1, OXA-48) along with ESBLs.

CONCLUSION:

K2 serotype is more prevalent among hvKP isolates. They can harbor ESBLs and Carbapenemase genes. K1 serotype is rather uncommon in K. pneumoniae. Acquisition of multidrug-resistant genes by these strains adds to their virulence and limits the treatment options.

Characterisation of virulence genes associated with pathogenicity in Klebsiella pneumoniae

Purpose

This study was undertaken to characterise the virulence factors in clinical strains of Klebsiella pneumoniae and analyse their association with various infections caused and also to determine the association between virulence factors and antimicrobial resistance profile.

Materials and Methods

A total number of 370 clinically significant, non-duplicate isolates of K. pneumoniae isolated from both hospitalised patients and patients attending clinics were included in this study. Polymerase chain reaction (PCR) was carried out for the detection of various virulence genes such as mucoviscosity-associated gene A (magA), gene associated with allantoin metabolism (allS), Klebsiella ferric iron uptake(Kfu), capsule-associated gene A (K2A), regulator of mucoid phenotype A (rmpA), enterobactin (entB), yersiniabactin (YbtS), aerobactin, Fimbrial adhesin (FimH) and uridine-diphosphate galacturonate 4-epimerase (uge). Antimicrobial susceptibility testing and PCR-based detection of beta-lactamase-encoding genes such as extended-spectrum beta-lactamases, AmpCs and carbapenemases were performed. Univariate analysis was done to find the association between virulence genes and mortality.

Results

The siderophore, entB, was present in most (90.5%) of the isolates. Of the 370 isolates, 345 carried multiple virulence genes; 15 harboured single virulence genes and 10 did not harbour any of the studied virulence genes. The most common combination of occurrence was entB and FimH. A mortality rate of 12.75% (38/298) was observed among hospitalised patients. None of the virulence genes had any significant association with mortality.

Conclusion

Pathogenic K. pneumoniae can harbour single to multiple virulence genes. Invasive infection with even a single virulence gene-harbouring K. pneumoniae can lead to poor outcomes. Both multidrug-resistant (MDR) and non-MDR K. pneumoniae can harbour a variety of virulence genes. None of the virulence genes have a significant association with mortality.

Epidemiology and outcomes of anal abscess in patients on chronic dialysis: a 14-year retrospective study

OBJECTIVES

We conducted this retrospective study to elucidate the clinical presentation and outcomes of anal abscess in chronic dialysis patients.

METHODS

We performed a chart review of patients who were hospitalized for anal abscess from Jan. 2002 to Dec. 2015. A total of 3,074 episodes of anal abscess were identified. Of these, 43 chronic dialysis patients with first-time anal abscess were enrolled. Patients were divided into a surgical group and a nonsurgical group according to the treatment received during hospitalization. The baseline characteristics, clinical findings, treatments and outcomes were obtained and analyzed. The endpoints of this study were in-hospital mortality, one-year mortality and one-year recurrence.

RESULTS

Of the 43 patients, 27 (62.7%) received surgical treatment, and 16 (37.2%) received antibiotic treatment alone. There was no significant difference in age, sex, body mass index, smoking habits, comorbidities, or dialysis characteristics between the two groups. Perianal abscess was the most common type of anal abscess, and 39.5% of patients experienced fistula formation. Most patients had mixed aerobic and anaerobic flora. Our data demonstrate that there was no significant difference in hospital stay, one-year survival or recurrence rate between the surgical group and nonsurgical group. However, there was a trend toward better in-hospital survival in patients who received surgical treatment (p=0.082).

CONCLUSION

In chronic dialysis patients with anal abscess, there was no statistically significant difference in clinical presentation and outcomes between the surgical and nonsurgical groups, although the surgical group had a trend of better in-hospital survival.

Clinical Features and Recurrence Pattern of Perianal Abscess in Patients with Acute Myeloid Leukemia

INTRODUCTION

Perianal abscess may develop during neutropenia periods in patients with acute myeloid leukemia (AML). The standard of care for perianal abscess in AML is unclear.

METHODS

We retrospectively collected patient data in our institute from 2009 to 2012.

RESULTS

Two hundred ninety-two patients with AML were analyzed. In total, 1,051 chemotherapy sessions were administered. Twenty-three patients experienced perianal abscess. Patients with perianal abscess were younger than those without (44 vs. 60 years, p < 0.0001). Perianal abscess developed in various phases of treatment and in the stem cell transplantation period. Twelve recurrences developed in 6 patients. Patients with a prior perianal abscess have a 10-fold risk of developing a subsequent abscess following further chemotherapy. The microbiology profile revealed that most pathogens were derived from the intestinal tracts, which was similar to the findings of previous studies. The 28-day mortality was 14.3% and the direct cause of death was not perianal abscess in any case. Surgical interventions had no impact on recurrence or survival.

CONCLUSION

In patients with AML, perianal abscess results from gastrointestinal tract pathogens. Many patients do not require surgical interventions. The mortality is low but recurrence is common following subsequent chemotherapies. Therefore, awareness of recurrence is important for the timely management of perianal abscess in AML.

Perianal Abscess and Proctitis by Klebsiella pneumoniae

Klebsiella pneumoniae (K. pneumoniae) can at times cause invasive infections, especially in patients with diabetes mellitus and a history of alcohol abuse. A 61-year-old man with diabetes mellitus and a history of alcohol abuse presented with abdominal and anal pain for two weeks. After admission, he underwent sigmoidoscopy, which revealed multiple ulcerations with yellowish exudate in the rectum and sigmoid colon. The patient was treated with ciprofloxacin and metronidazole. After one week, follow up sigmoidoscopy was performed owing to sustained fever and diarrhea. The lesions were aggravated and seemed webbed in appearance because of damage to the rectal mucosa. Abdominal computed tomography and rectal magnetic resonance imaging were performed, and showed a perianal and perirectal abscess. The patient underwent laparoscopic sigmoid colostomy and perirectal abscess incision and drainage. Extended-spectrum beta-lactamase-producing K. pneumoniae was identified in pus culture. The antibiotics were switched to ertapenem. He improved after surgery and was discharged. K. pneumoniae can cause rapid invasive infection in patients with diabetes and a history of alcohol abuse. We report the first rare case of proctitis and perianal abscess caused by invasive K. pneumoniae infection.

Treatment of anal fistula and abscess

The glands of Hermann and Desfosses, located in the thickness of the anal canal, drain into the canal at the dentate line. Infection of these anal glands is responsible for the formation of abscesses and/or fistulas. When this presents as an abscess, emergency drainage of the infected cavity is required. At the stage of fistula, treatment has two sometimes conflicting objectives: effective drainage and preservation of continence. These two opposing constraints explain the existence of two therapeutic concepts. On one hand the laying-open of the fistulous tract (fistulotomy) in one or several operative sessions remains the treatment of choice because of its high cure rates. On the other hand surgical closure with tract ligation or obturation with biological components preserves sphincter function but suffers from a higher failure rate.

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.

Candida albicans as the Sole Organism Cultured from a Perirectal Abscess

Perirectal abscess is a common colorectal condition that may be present with or without a fistula. In most cases where a fistula coexists the organisms cultured are gut-derived organisms whereas skin-derived organisms are more common in patients without fistula formation. Candida albicans, despite being an microorganism often found in the gastrointestinal tract, has not previously been reported as an isolate from a perirectal abscess culture. Here we report the case of a patient taking cefazolin in whom a perirectal abscess was diagnosed via computed tomography and aspiration of which demonstrated growth of only C. albicans. Prior literature has demonstrated that the microorganisms cultured from patients with perirectal abscesses do not differ between patients in whom antimicrobials had been used previously and those who were antimicrobial-naïve, suggesting that there is a possibility that C. albicans is the sole organism responsible for the perirectal abscess in our patient. The patient underwent surgical drainage and was discharged with fluconazole and piperacillin/tazobactam, which led to the satisfactory recovery of the patient.