Primary Aortoappendicular Fistula Arising from an Infected, Chronic, Contained, Ruptured Abdominal Aortic Aneurysm

Gastrointestinal bleeding can be caused by a variety of pathologies. Primary aortoappendicular fistula is rare and, in our case, arose in addition to a chronic contained rupture sac of an abdominal aortic aneurysm. Clinical diagnosis is difficult. Aortic aneurysmorrhaphy along with extensive debridement and emphasis on antibiotic therapy is curative.

[Pneumatosis cystoides intestini caeci--a pseudotumor presented at autopsy]

A large focus of cystic intestinal pneumatosis appeared as an accidental finding in a 59-year-old man suffering from obstructive lung disease, with cor pulmonale as the cause of death. The gas pseudocysts were found in the submucosa, muscularis propria and in the subserosal space. The pseudocysts were lined by flattened cells of connective tissue origin with presence of occasional macrophages. We believe that the lesion started by focal damage of the mucosal membrane, which was followed by penetration of stool particles with microbes into the submucosa. E. coli and Morganella morgani are the probable producers of the gas bullets.

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.

Acute isolated tuberculous appendicitis

Non-pulmonary tuberculosis is found with different frequencies in different countries of the world. It is said to constitute about 4% of all tuberculosis cases in Poland, about 25% in England and Wales and about 17% in the USA. It seems that these differences are the result of differences in rates of diagnosis and registration of new tuberculosis cases. This in turn is influenced by public health funding in the individual countries. In this work, we present a case of acute, isolated, tuberculous inflammation of the appendix. We call attention to the fact that pre-operative diagnosis is practically impossible. Clinical symptoms do not point to inflammatory changes. Only surgical evaluation, and especially the result of histopathological examination make it to possible to establish the final diagnosis to initiation of anti-tuberculous treatment.

Bacterial-induced inflammation in germ-free rabbit appendix

The intestinal ecosystem is defined by a series of interactions between the microbiota, the mucosal epithelium, and the gut-associated lymphoid tissue (GALT). Perturbations in the fine balance of the interactions between these components can result in gastrointestinal diseases such as inflammatory bowel disease (IBD). The pathophysiology of IBD is thought to develop as a result of dysregulated mucosal immune responses to normal luminal microflora. Several animal models for IBD have been developed and underscore the role of the immune system in development of disease. Most of the existing animal models studying IBD are based on the use of chemically induced IBD or of genetically modified and germ-free animals. It is, however, important to study inflammatory responses that can develop from interactions between bacteria, the mucosal epithelium, and GALT in animals that are not genetically modified or immunocompromised. In this report, we document the use of a germ-free ligated rabbit appendix model to induce inflammatory changes in response to specific bacteria. With the introduction of a Bacteroides vulgatus isolate from humans into the germ-free ligated appendix, we found chronic inflammatory changes, including glandular distortion, gland drop-out, decreased goblet cells, and crypt abscess formation. However, with the introduction of other experimental luminal contents, we observed no inflammation. These results show that specific microbial composition can induce inflammation. We suggest that this model may be useful to study the mechanism by which specific bacteria establish inflammatory responses in the gut.

Bacterial translocation in the normal human appendix parallels the development of the local immune system

Experimental modes and pathological conditions may result in bacterial translocation (BT), that is, the passage of indigenous bacteria colonizing the intestine through the intestinal mucosa to mesenteric lymph nodes. Yet no data are available on BT in the normal human gut. We determined the occurrence of BT and its extent in histologically normal, incidentally removed human vermiform appendices (VA) from individuals of different ages and correlated the findings with the development with age of associated lymphatic tissue. BT appears to pertain to normal antigen-sampling processes of the GALT in the VA. It also parallels the development of the GALT and its maintenance during adulthood. In the first two weeks after birth, when bacterial colonization of the gut evolves and when the VA lacks the protection of secretory IgA, BT was not detected. Thereafter, BT occurs along with development of the local GALT, which is fully built up after the first year. A physiological uptake of, or invasion by, bacteria may be instrumental (1) for tolerance induction against the indigenous flora and (2) for the stimulation and normal development of the GALT.

Interaction of pathogenic bacteria with rabbit appendix M cells: bacterial motility is a key feature in vivo

Rabbit appendix consists mainly of lymphoid follicles (LF) covered by M cells, the specialized antigen-sampling cells of the mucosal immune system, and surrounded by glandular epithelium. Until now, these M cells have been characterized morphologically and histologically by using cellular markers. Here, the adhesion and transport of pathogenic bacteria were investigated to assess the function of M cells of the appendix. We used the enteroinvasive motile Salmonella typhimurium and the rabbit enteropathogenic non-motile Escherichia coli RDEC-1, which are known to target specifically rabbit M cells of Peyer's patches (PPs). We found that S. typhimurium efficiently attached and was transported through appendix M cells in vivo. In contrast to S. typhimurium, RDEC-1 targeted M cells only ex vivo, when bacteria were allowed to have direct contact with the surface of the follicle. The difference in interaction of the two bacteria with appendix M cells led us to investigate whether this could be correlated with the lack of motility of RDEC-1. We used an aflagellate mutant of S. typhimurium and found that it had the same infection phenotype as RDEC-1. Gene complementation restored the efficiency of infection to that of S. typhimurium wild-type strain. In conclusion, we show that M cells of the appendix display features of the canonical M cells of PP, since they efficiently sample luminal pathogenic bacteria. However, due to the morphology of the appendix, motile bacteria appear to be more potent in their interactions with appendix M cells.

[The role of enteropathogenic infection, local immunity, and autosensibilisation in pathogenesis of acute surgical diseases of peritoneal cavity by the example of acute appendicitis]

The complex of interrelated pathogenic factors in development of postoperative suppurative inflammatory complication with abdominal cavity organs lesion was studied on the example of an acute appendicitis. It includes enteropathogenic microorganisms, insufficiency of local immunity, deficiency of immunoglobulins, lysozym. Findings show the possibility in seeking the measures of prevention of emergent state, in particular, an acute appendicitis.

Role of commensal bacteria in development of gut-associated lymphoid tissues and preimmune antibody repertoire

Intestinal bacteria are required for development of gut-associated lymphoid tissues (GALT), which mediate a variety of host immune functions, such as mucosal immunity and oral tolerance. In rabbits, the intestinal microflora are also required for developing the preimmune Ab repertoire by promoting somatic diversification of Ig genes in B cells that have migrated to GALT. We studied the mechanism of bacteria-induced GALT development. Bacteria were introduced into rabbits in which the appendix had been rendered germfree by microsurgery (we refer to these rabbits as germfree-appendix rabbits). We then identified specific members of the intestinal flora that promote GALT development. The combination of Bacteroides fragilis and Bacillus subtilis consistently promoted GALT development and led to development of the preimmune Ab repertoire, as shown by an increase in somatic diversification of VDJ-C micro genes in appendix B cells. Neither species alone consistently induced GALT development, nor did Clostridium subterminale, Escherichia coli, or Staphylococcus epidermidis. B. fragilis, which by itself is immunogenic, did not promote GALT development; hence, GALT development in rabbits does not appear to be the result of an Ag-specific immune response. To identify bacterial pathways required for GALT development, we introduced B. fragilis along with stress-response mutants of B. subtilis into germfree-appendix rabbits. We identified two Spo0A-controlled stress responses, sporulation and secretion of the protein YqxM, which are required for GALT development. We conclude that specific members of the commensal, intestinal flora drive GALT development through a specific subset of stress responses.

[Actinomycosis of the appendix. Report of two cases]

INTRODUCTION

We report two patients with actinomycosis of the appendix extending to the caecum and the ileum, and diagnosed postoperatively on histological analysis, the authors reviewed the literature.

EXEGESIS

Actinomycosis of the appendix can be acute or chronic. Diagnosis may be obtained preoperatively on the analysis of aspiration or biopsy material under CT scan control. It is frequently done postoperatively on the analysis of surgical specimen. Actinomycosis can be treated with antibiotics only during six months if the diagnosis is made preoperative, by surgery followed by antibiotics during 6-12 months, according to the extension of the actinomycosis, if the diagnosis is made after surgery, and by a combination of a surgery and antibiotics in complex forms.

CONCLUSION

Actinomycosis of the appendix is an infrequent pathology that merits to be known. With antibiotic therapy, we can avoid surgery or wide resections.

Helicobacter pylori infection in patients undergoing appendectomy

AIMS

Helicobacter pylori has been found in the upper gastrointestinal tract; it is incriminated as aetiological factor in various pathological conditions. This prospective study assesses the presence of this microorganism in the appendix flora and the possible role of its infection in the pathogenesis of acute appendicitis.

METHODS

H. pylori was investigated in 46 consecutive patients undergoing emergent appendectomy for presumed acute appendicitis. Blood sample for serological test of H. pylori infection was drawn before operation. The removed appendix specimen was stained for H. pylori; confirmation was made by PCR (Polymerase Chain Reaction) analysis. The intensity of inflammation was determined pathologically grading from no inflammation to gangrenous appendicitis. Statistical analysis was made using the chi-square test.

RESULTS

Seropositivity for H. pylori infection was found in 18 patients (39%), but the microbe was detected in just two appendix specimens (4%). In all seropositive patients acute appendicitis was confirmed by the pathology study; serous (33%) and purulent or gangrenous (67%). The latter incidence in the seronegative patients was 50%. There were found eight specimens (17%) negative for inflammation dealing all with seronegative patients.

CONCLUSIONS

It seems that H. pylori colonizes the appendix in small proportion and is unlikely to be associated in direct correlation with acute appendicitis. However, seropositive patients with acute inflammation are likely to suffer from purulent or gangrenous form.

Initial nonoperative management for periappendiceal abscess

PURPOSE

Our goal was to compare initial operative and nonoperative management for periappendiceal abscess complicating appendicitis.

METHODS

This study is a retrospective review of 155 consecutive patients with appendicitis complicated by periappendiceal abscess treated between 1992 and 1998. Eighty-eight patients were treated initially nonoperatively, and 67 patients were treated operatively. All patients had localized abdominal tenderness and either computed tomography or intraoperative documentation of an abscess.

RESULTS

Our patient population consisted of 107 males and 48 females, with an average age of 33 (range, 16-75) years. Age, gender, comorbidity, white blood cell count, temperature, and heart rate did not differ significantly between groups. For the initial nonoperative management group, the failure rate was 5.8 percent and the appendicitis recurrence rate was 8 percent after a mean follow-up of 36 weeks. The response to treatment of the initial nonoperative group and the initial operative group was compared by length of stay (9 +/- 5 days vs. 9 +/- 3 days; P = not significant), days until white blood cell count normalized (3.8 +/- 4 days vs. 3.1 +/- 3 days; P = not significant), days until temperature normalized (3.2 +/- 3 days vs. 3.1 +/- 2 days; P = not significant), and days until a regular diet was tolerated (4.7 +/- 4 days vs. 4.6 +/- 3 days; P = not significant). Complication rate was significantly lower in the nonoperative group (17 vs. 36 percent; P = 0.008).

CONCLUSIONS

Initial nonoperative management of appendicitis complicated by periappendiceal abscess is safe and effective. Patients undergoing initial nonoperative management have a lower rate of complications, but they are at risk for recurrent appendicitis.

Mycobacterial spindle cell pseudotumor of the appendix vermiformis in a patient with aids

Mycobacterial pseudotumor (MP) is a rare pathologic presentation of both Mycobacterium tuberculosis and non-tuberculous mycobacterial disease, hitherto reported to occur only in immunosuppressed patients with or without human immunodeficiency virus infection. This lesion shares close pathologic resemblance to certain mesenchymal neoplasms, particularly Kaposi's sarcoma (KS), from which it must be properly differentiated due to distinct prognosis and therapy. We report a case of MP obliterating the lumen of the appendix vermiformis in a 34-year-old patient who died of complications of AIDS at our hospital in Rio de Janeiro. A total of 24 cases of MP (including our patient) have been described in the literature. MP has been found especially in lymph nodes, but extranodal lesions have been described in the skin, spleen, lung, bone marrow, brain and, in our patient, the appendix vermiformis. We offer a review of the other 23 published case reports of MP in both HIV-infected and uninfected patients and discuss the pathologic features that differentiate MP from KS.

The role of Yersinia enterocolitica and Yersinia pseudotuberculosis in granulomatous appendicitis: a histologic and molecular study

Granulomatous appendicitis is an enigmatic entity. Purported causes include Crohn's disease, foreign body reactions, sarcoidosis, and infectious agents; however, most cases remain idiopathic. Yersinia enterocolitica (YE) and Y. pseudotuberculosis (YP) have been implicated as causes of appendicitis, ileocolitis, and mesenteric adenitis. The authors examined the potential role of YE and YP in granulomatous appendicitis using histologic and molecular methods. Forty cases of granulomatous appendicitis were evaluated for histologic features including transmural inflammation, number and character of granulomas, and mucosal changes. Twort Gram, Grocott methenamine-silver (GMS), and Ziehl-Neelsen stains were evaluated, and polymerase chain reaction (PCR) analysis was performed to identify pathogenic YP and YE. Twenty-five percent (10 of 40) of the cases were positive for pathogenic Yersinia by PCR (four YE, four YP, and two with both species). Prominent histologic features included epithelioid granulomas with lymphoid cuffing, transmural inflammation with lymphoid aggregates, mucosal ulceration, and cryptitis. One Yersinia-positive case contained mural Gram-negative bacilli; fungal and acid-fast bacilli stains were all negative. Except for one culture-negative case, serologies and cultures were not done or results were unavailable. Two Yersinia-positive patients were diagnosed subsequently with Crohn's disease, suggesting a possible relationship between the two entities. No other patients developed significant sequelae. YE and YP are important causes of granulomatous appendicitis, and Yersinia infection may mimic Crohn's disease. No histologic features distinguish reliably between Yersinia species, or between Yersinia-positive and Yersinia-negative cases. Because special stains and cultures are often not diagnostic, PCR analysis is an excellent technique for the diagnosis of Yersinia.

In vitro antibiotic susceptibility of Bacteroides fragilis strains isolated from excised appendix of patients with phlegmonous or gangrenous appendicitis

Out of 34 studied after-appendectomy tissues of adult and child patients 86 different strains of anaerobes were isolated. The antibiotic susceptibility of 30 isolated B. fragilis strains was tested using E tests. All studied strains were sensitive to imipenem, clindamycin and penicillin/tazobactam. Sensitivity to penicillin and cefoxitin was variable among these strains. One strain resistant to metronidazole (MIC--256 mg/L) and 3 strains with increased MIC to metronidazole were detected. Most of isolated strains were beta-lactamase producers.

Intestinal microflora and diversification of the rabbit antibody repertoire

The rabbit establishes its primary Ab repertoire by somatically diversifying an initial repertoire that is limited by restricted VH gene segment usage during VDJ gene rearrangement. Somatic diversification occurs in gut-associated lymphoid tissue (GALT), and by about 1-2 mo of age nearly all Ig VDJ genes are somatically diversified. In other species that are known to establish their primary Ab repertoire by somatic diversification, such as chicken, sheep, and cattle, diversification appears to be developmentally regulated: it begins before birth and occurs independent of exogenous factors. Because somatic diversification in rabbit occurs well after birth in GALT, the diversification process may not be developmentally regulated, but may require interaction with exogenous factors derived from the gut. To test this hypothesis, we examined Ab repertoire diversification in rabbits in which the appendix was ligated shortly after birth to prevent microbial colonization and all other organized GALT was surgically removed. We found that by 12 wk of age nearly 90% of the Ig VDJ genes in PBL were undiversified, indicating that intestinal microflora are required for somatically diversifying the Ab repertoire. We also examined repertoire diversification in sterilely derived remote colony rabbits that were hand raised away from contact with conventional rabbits and thereby acquired a different gut microflora. In these remote colony rabbits, GALT was underdeveloped, and 70% of the Ig VDJ genes in PBL were undiversified. We conclude that specific, currently unidentified intestinal microflora are required for Ab repertoire diversification.

Comparative in vitro activities of trovafloxacin (CP-99,219) against 221 aerobic and 217 anaerobic bacteria isolated from patients with intra-abdominal infections

Four hundred thirty-eight bacteria cultured from specimens of patients with serious intra-abdominal infections were tested by agar dilution against trovafloxacin and other quinolones and antimicrobial agents. Trovafloxacin inhibited 435 strains (99.3%) at < or =2 microg/ml. All the quinolones had similar activities against Enterobacteriaceae and Pseudomonas sp., but trovafloxacin showed superior activities against streptococci, enterococci, and anaerobic organisms. Because of its excellent in vitro activities against diverse bacteria, trovafloxacin has potential use as a single agent for polymicrobial infections.

Characteristics of an unusual anaerobic pigmented gram-negative rod isolated from normal and inflamed appendices

During our studies of the bacterial etiology of appendicitis, we often isolated a previously undescribed anaerobic gram-negative rod. This organism resembled the Bacteroides fragilis group because it was resistant to bile and because of its special-potency-disk pattern (resistant to vancomycin, kanamycin, and colistin), but unlike the B. fragilis group, this bacterium produced brown pigment on media containing hemolysed blood. The cellular fatty acid pattern, with iso-C15:0 being the predominant acid, was most closely related to the fatty acid profile of Porphyromonas species; however, this organism differed from Porphyromonas species by being bile-resistant and by not producing butyrate as a metabolic endproduct. Enzymatic activities of 31 isolates were determined with use of the API ZYM system and Rosco diagnostic tablets. These profiles were different from those of Prevotella, Porphyromonas, and related species. This organism was isolated from 40% of appendiceal tissue samples; no obvious qualitative or quantitative difference in rates of isolation from patients with inflamed or normal appendices was observed.

Efficacy of azithromycin and rifabutin in preventing infection by Mycobacterium avium complex in beige mice

We investigated the potential of the azalide, azithromycin, and rifabutin in preventing disseminated infection due to Mycobacterium avium complex (MAC) in beige mice. Azithromycin 200 mg/kg, rifabutin (30 mg/kg or 60 mg/kg) were administered by gavage 6 days before mice were challenged orally with 10(8) cfu MAC and daily for 10 days thereafter during which time the mice were again challenged with the same inoculum on alternate days (days +1, +3, +5, +7, and +9). Sixty-four days later, the presence of bacteria in the blood and the number of viable bacteria in liver, spleen and appendix were estimated. Treatment with azithromycin and 60 mg/kg/day rifabutin but not 30 mg/kg/day, significantly decreased the incidence of bacteraemia and the number of bacteria in the appendix. The administration of azithromycin resulted in significantly fewer MAC in the liver and spleen but not in the appendix whereas the converse was true of 60 mg/kg rifabutin. Our results indicate that both azithromycin and rifabutin can prevent MAC disseminated infection, but that the azalide is more effective than the rifamycin in reducing the burden of infection.