Intestinal inflammatory pseudotumour with regional lymph node involvement: identification of a new bacterium as the aetiological agent

Progressive deterioration of the upper respiratory tract and the gut microbiomes in children during the early infection stages of COVID-19

Children are less susceptible to coronavirus disease 2019 (COVID-19), and they have manifested lower morbidity and mortality after infection, for which a multitude of mechanisms may be considered. Whether the normal development of the gut-airway microbiome in children is affected by COVID-19 has not been evaluated. Here, we demonstrate that severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection alters the upper respiratory tract and the gut microbiomes in nine children. The alteration of the microbiome is dominated by the genus Pseudomonas, and it sustains for up to 25–58 days in different individuals. Moreover, the patterns of alternation are different between the upper respiratory tract and the gut. Longitudinal investigation shows that the upper respiratory tract and the gut microbiomes are extremely variable among children during the course of COVID-19. The dysbiosis of microbiome persists in 7 of 8 children for at least 19–24 days after discharge from the hospital. Disturbed development of both the gut and the upper respiratory microbiomes and prolonged dysbiosis in these nine children imply possible long-term complications after clinical recovery from COVID-19, such as predisposition to the increased health risk in the post-COVID-19 era.

A Rare Case of Inflammatory Myofibroblastic Tumor of the Prostate and Review of the Literature

BACKGROUND

Inflammatory myofibroblastic tumor (IMT) is a rare type of soft-tissue neoplasm. IMT of the urinary tract is more common in the bladder and kidneys. Prostatic IMT is extremely rare.

CASE REPORT

We present a rare case of IMT of the prostate and a literature review on this condition. The patient was a 72-year-old man who presented with urinary symptoms. Transrectal needle biopsy of the prostate revealed prostatic adenocarcinoma with nodular hyperplasia. Radical prostatectomy revealed IMT without residual adenocarcinoma. On immunohistochemical examination, the tumor cells showed positive immunoreactivity for α-smooth muscle actin, CD10, CD34, and desmin but negative immunoreactivities for anaplastic lymphoma kinase (ALK), receptor tyrosine kinase (c-KIT), and S-100 protein. The patient underwent regular follow-up examination. No recurrence was observed 4 months after the diagnosis.

CONCLUSION

This was a case of IMT arising in the prostate. Pathologists should be aware of such an entity whenever they see spindle-cell lesions in the transrectal needle biopsy of the prostate.

A Rare Case of Inflammatory Myofibroblastic Tumor of the Prostate and Review of the Literature

BACKGROUND

Inflammatory myofibroblastic tumor (IMT) is a rare type of soft-tissue neoplasm. IMT of the urinary tract is more common in the bladder and kidneys. Prostatic IMT is extremely rare.

CASE REPORT

We present a rare case of IMT of the prostate and a literature review on this condition. The patient was a 72-year-old man who presented with urinary symptoms. Transrectal needle biopsy of the prostate revealed prostatic adenocarcinoma with nodular hyperplasia. Radical prostatectomy revealed IMT without residual adenocarcinoma. On immunohistochemical examination, the tumor cells showed positive immunoreactivity for α-smooth muscle actin, CD10, CD34, and desmin but negative immunoreactivities for anaplastic lymphoma kinase (ALK), receptor tyrosine kinase (c-KIT), and S-100 protein. The patient underwent regular follow-up examination. No recurrence was observed 4 months after the diagnosis.

CONCLUSION

This was a case of IMT arising in the prostate. Pathologists should be aware of such an entity whenever they see spindle-cell lesions in the transrectal needle biopsy of the prostate.

Dietary l-arginine Supplementation Alleviates the Intestinal Injury and Modulates the Gut Microbiota in Broiler Chickens Challenged by Clostridium perfringens

Our previous reports suggested that Dietary l-arginine supplementation attenuated gut injury of broiler chickens infected with Clostridium perfringens by enhancing intestinal immune responses, absorption and barrier function, but its effect on the gut microbiome of broiler chickens remains unclear. This experiment aimed at evaluating the effects of Dietary l-arginine supplementation on the gut bacterial community composition and function of broiler chickens challenged with C. perfringens. In total, 105 1-day-old male Arbor Acres broiler chickens were assigned to three groups: Control (CTL), C. perfringens-challenged (CP), and C. perfringens-challenged and fed diet supplemented with 0.3% l-arginine (ARGCP) groups. The challenge led to macroscopic and histomorphological gut lesions, decreased villus height and increased the number of Observed species, Shannon, Chao1 and ACE indices of ileal microbiota, whereas l-arginine addition reversed these changes. Moreover, the three treatments harbored distinct microbial communities (ANOSIM, P < 0.05). At the genus level, 24 taxa (e.g., Nitrosomonas spp., Coxiella spp., Ruegeria spp., and Thauera spp.) were significantly more abundant in CP group than in CTL group (P < 0.05), whereas the levels of 23 genera of them were significantly decreased by l-arginine supplementation (P < 0.05). The abundances of only 3 genera were different between CTL and ARGCP groups (P < 0.05). At the species level, the challenge promoted the relative abundance of Nitrospira sp. enrichment culture clone M1-9, Bradyrhizobium elkanii, Nitrospira bacterium SG8-3, and Pseudomonas veronii, which was reversed by l-arginine supplementation (P < 0.05). Furthermore, the challenge decreased the levels of Lactobacillus gasseri (P < 0.05). Predictive functional profiling of microbial communities by PICRUSt showed that compared with CP group, ARGCP group had enriched pathways relating to membrane transport, replication and repair, translation and nucleotide metabolism and suppressed functions corresponding to amino acid and lipid metabolisms (P < 0.05). The relative abundances of KEGG pathways in l-arginine-fed broilers were almost equal to those of the controls. In conclusion, l-arginine alleviated the gut injury and normalized the ileal microbiota of C. perfringens-challenged chickens to resemble that of unchallenged controls in terms of microbial composition and functionality.

Hepatogastric Inflammatory Pseudotumor Presumably Deriving from Prior Amebic Infection

Introduction

Inflammatory pseudotumor is a rare entity with a clinical and radiographic presentation that is difficult to differentiate from malignancy. This is a case report of a large hepatogastric inflammatory pseudotumor that presumably developed from a prior amebic pseudocyst.

Case Report

A 14-year-old boy presented with increasing vomiting, epigastric pain, dysphagia, asthenia and weight loss. The clinical history included an amebic infection at the age of 2 months. Instrumental investigations revealed an 8 x 6 cm left subdiaphragmatic mass inseparable from the gastric fundus, which appeared to infiltrate the left hepatic lobe. Surgery disclosed a bulky mass adhering to the gastric fundus and left hepatic lobe that prompted total gastrectomy, resection of the second and third hepatic segments, and Roux-en-Y esophagojejunal loop anastomosis. Histology subsequently confirmed that this was a pseudocyst with a large calcified nucleus surrounded by myofibroblastic proliferation associated with a diffuse lymphoplasmacytic infiltrate affecting the gastric wall and hepatic parenchyma, hence the final diagnosis of inflammatory pseudotumor, presumably in response to a prior amebic pseudocyst.

Conclusions

Inflammatory pseudotumor is a rare entity that is seldom found in the stomach. The particular interest of the present case lies in the fact that it developed in the stomach and liver, presumably deriving from a previous amebic pseudocyst.

Arachidonic acid sex-dependently affects obesity through linking gut microbiota-driven inflammation to hypothalamus-adipose-liver axis

Unraveling the role of dietary lipids is beneficial to treat obesity and metabolic dysfunction. Nonetheless, how dietary lipids affect existing obesity remains unknown. Arachidonic acid (AA), a derivative of linoleic acid, is one of the crucial n-6 fatty acids. The aim of this study was to investigate whether AA affects obesity through associating microbiota-driven inflammation with hypothalamus-adipose-liver axis. Four-week old C57BL/6J mice were fed with a high-fat diet (HFD, 45% fat) for 10weeks to induce obesity, and then fed a HFD enriched with 10g/kg of AA or a continuous HFD in the following 15weeks. Systemic adiposity and inflammation, metabolic profiles, gut microbiota composition, short-chain fatty acids production, hypothalamic feeding regulators, browning process of adipocytes, hepatosteatosis, and insulin resistance in adipose were investigated. The results indicated that AA aggravates obesity for both genders whereas sex-dependently affects gut microbiota composition. Also, AA favors pro-inflammatory microbiota and reduces butyrate production and circulating serotonin, which augments global inflammation and triggers hypothalamic leptin resistance via microglia accumulation in male. AA exacerbates non-alcoholic steatohepatitis along with amplified inflammation through TLR4-NF-κB pathway and induces insulin resistance. Reversely, AA alleviates obesity-related disorders via rescuing anti-inflammatory and butyrate-producing microbiota, up-regulating GPR41 and GPR109A and controlling hypothalamic inflammation in female. Nevertheless, AA modifies adipocyte browning and promotes lipid mobilization for both genders. We show that AA affects obesity likely through a gut-hypothalamus-adipose-liver axis. Our findings formulate recommendations of n-6 fatty acids like AA from dietary intake for obese subjects preferably in a sexually dimorphic way.

Degradation of Benzene by Pseudomonas veronii 1YdBTEX2 and 1YB2 Is Catalyzed by Enzymes Encoded in Distinct Catabolism Gene Clusters

Pseudomonas veronii 1YdBTEX2, a benzene and toluene degrader, and Pseudomonas veronii 1YB2, a benzene degrader, have previously been shown to be key players in a benzene-contaminated site. These strains harbor unique catabolic pathways for the degradation of benzene comprising a gene cluster encoding an isopropylbenzene dioxygenase where genes encoding downstream enzymes were interrupted by stop codons. Extradiol dioxygenases were recruited from gene clusters comprising genes encoding a 2-hydroxymuconic semialdehyde dehydrogenase necessary for benzene degradation but typically absent from isopropylbenzene dioxygenase-encoding gene clusters. The benzene dihydrodiol dehydrogenase-encoding gene was not clustered with any other aromatic degradation genes, and the encoded protein was only distantly related to dehydrogenases of aromatic degradation pathways. The involvement of the different gene clusters in the degradation pathways was suggested by real-time quantitative reverse transcription PCR.

The arable ecosystem as battleground for emergence of new human pathogens

Disease incidences related to Escherichia coli and Salmonella enterica infections by consumption of (fresh) vegetables, sprouts, and occasionally fruits made clear that these pathogens are not only transmitted to humans via the "classical" routes of meat, eggs, and dairy products, but also can be transmitted to humans via plants or products derived from plants. Nowadays, it is of major concern that these human pathogens, especially the ones belonging to the taxonomical family of Enterobacteriaceae, become adapted to environmental habitats without losing their virulence to humans. Adaptation to the plant environment would lead to longer persistence in plants, increasing their chances on transmission to humans via consumption of plant-derived food. One of the mechanisms of adaptation to the plant environment in human pathogens, proposed in this paper, is horizontal transfer of genes from different microbial communities present in the arable ecosystem, like the ones originating from soil, animal digestive track systems (manure), water and plants themselves. Genes that would confer better adaptation to the phytosphere might be genes involved in plant colonization, stress resistance and nutrient acquisition and utilization. Because human pathogenic enterics often were prone to genetic exchanges via phages and conjugative plasmids, it was postulated that these genetic elements may be hold key responsible for horizontal gene transfers between human pathogens and indigenous microbes in agroproduction systems. In analogy to zoonosis, we coin the term phytonosis for a human pathogen that is transmitted via plants and not exclusively via animals.

Pulmonary actinomycosis as a rare cause of inflammatory myofibroblastic tumor: a case report

Pulmonary inflammatory myofibroblastic tumor encompasses a heterogeneous spectrum of reactive, infectious, and neoplastic entities. It is composed of spindle-shaped myofibroblastic cells in a background of inflammatory cells and collagen fibres. Actinomycosis is a bacterial infection. It infects the lower respiratory tracts by inhalation or aspiration of oropharyngeal or upper gastrointestinal materials. Only eight cases of pulmonary IMT associated with actinomycosis have been reported in the literature so far. This is the ninth case reported.

Recurrence of inflammatory myofibroblastic tumor in bladder secondary to prostate treated with laparoscopic radical cystectomy

BACKGROUND

Inflammatory myofibroblastic tumor (IMT) is a rare borderline tumor. The nomenclature of this disease is confused in the literature.

CASE REPORT

In this report, the case of a 62-year-old man with IMT recurrence of bladder secondary to prostate is presented. The possible etiology of IMT is discussed, along with its clinical manifestation and pathological features. The patient received a laparoscopic bladder radical resection. The pathology finding demonstrated the diagnosis of IMT and no regional lymph node involvement.

CONCLUSIONS

IMT is a borderline tumor and unlikely to metastasize to regional lymph nodes. The patient has been observed for 2 years without recurrence.

Pyrimidine biosynthesis in Pseudomonas veronii and its regulation by pyrimidines

Pyrimidine biosynthesis in the nutritionally versatile bacterium Pseudomonas veronii ATCC 700474 appeared to be controlled by pyrimidines. When wild type cells were grown on glucose in the presence of uracil, four enzyme activities were depressed while all five enzyme activities increased in succinate-grown cells supplemented with uracil. Independent of carbon source, orotic acid-grown cells elevated aspartate transcarbamoylase, dihydroorotase, orotate phosphoribosyltransferase or OMP decarboxylase activity. Pyrimidine limitation of glucose-grown pyrimidine auxotrophic cells lacking OMP decarboxylase activity resulted in at least a doubling of the enzyme activities relative to their activities in uracil-grown cells. Less derepression of the enzyme activities was observed after pyrimidine limitation of succinate-grown mutant cells possibly due to catabolite repression. Aspartate transcarbamoylase activity in Ps. veronii was regulated at the level of enzyme activity since the enzyme was strongly inhibited by pyrophosphate, UDP, UTP, ADP, ATP and GTP. Overall, the regulation of pyrimidine biosynthesis in Ps. veronii could be used to differentiate it from other taxonomically related species of Pseudomonas.

Mesenteric myofibroblastic tumor: NSAID therapy after incomplete resection

Myofibroblastic tumors are inflammatory tumors that arise in viscera and soft tissue; their etiopathology is poorly understood. They are capable of infiltration of adjacent organs, local recurrence after surgical resection, and even of distant metastasis. These characteristics result in persistent debate as to the nature of these lesions - whether they are inflammatory or neoplastic, benign or malignant lesions? Diagnosis is almost always made based on histopathological findings. Traditional management is complete surgical excision, but this may be difficult or impossible when the lesion develops in proximity to vital structures. We report the case of a 59-year-old man who was treated in our institution for mesenteric myofibroblastic tumor. Complete resection was not possible due to local infiltration of the mesentery. Recurrence was noted 3 months after surgery; treatment with steroidal and then non-steroidal anti-inflammatory medications (NSAIDs) resulted in clinical and radiologic regression of the tumor.

Myocbacterium-avium intracellulare associated inflammatory pseudotumor of the anterior nasal cavity

In this case report, we describe an unusual case of mycobacterial associated inflammatory pseudotumor that occurred in a patient with a previous history of cocaine abuse. We discuss inflammatory pseudotumor (IPT) in general and emphasize the rare entity where an associated mycobacterial infection is seen. The histogenesis is not yet completely understood. The lesion can pose challenges for practicing pathologists and a misdiagnosis of malignancy can occur at multiple facets. A discussion about the differential diagnosis and clues to make the distinction is presented. In addition to spindle cell proliferation, the presence of a background of mixed inflammatory cell infiltrate and foamy macrophages are clues to make the diagnosis. In the case of mycobacteria associated IPT, Acid Fast Bacilli (AFB) stains will easily highlight the organisms confirming the diagnosis.

A successfully treated inflammatory myofibroblastic tumor of the mandible with long-term follow-up and review of the literature

Inflammatory myofibroblastic tumor (IMT) of the oral cavity is an extremely rare clinical and pathological disease entity. It was originally described in the lung but has recently been reported in various anatomic sites. We report such a case of inflammatory myofibroblastic tumor of the mandible in a 14-year-old girl. The patient presented with an aggressive ulcerative soft tissue mass of 3 months duration in the mandibular molar gingiva. Histologically, the lesion was composed of fibroblastic or myofibroblastic spindle cell proliferations with infiltrative margins in an inflammatory background. Immunohistochemically, the fibroblastic or myofibroblastic spindle cells were positive for vimentin, α-smooth muscle actin, and Ki-67 (MIB-1) but negative for desmin, pan-cytokeratin, S-100 protein, CD34, CD68, CD99, bcl-2, β-catenin, estrogen receptor, progesterone receptor, ALK-1, and p53. These spindle cells were focally and weakly Ki-67- (MIB-1-) positive. The MIB-1 labeling index was 5%. The results of in situ hybridization for Epstein-Barr virus-encoded-RNA were negative. The ratio of IgG4+/IgG+ plasma cells was about 10%. A pathological diagnosis of inflammatory myofibroblastic tumor was made. The postoperative course was uneventful, and the patient has had no recurrence in the 10-year follow-up period. Although no evidence of oral inflammatory myofibroblastic tumor recurrence or malignant transformation has been reported, it has been observed that in inflammatory myofibroblastic tumors of other regions, a prolonged follow-up is necessary after surgical resection. No other case of an IMT patient under 20 years of age has appeared in either the English or the Japanese literature.

Nodal inflammatory pseudotumor caused by luetic infection

Inflammatory pseudotumor of lymph nodes (IPT-LN) represents an unusual cause of lymphadenitis of unknown etiology. Upon the observation of a case of IPT-LN associated with Treponema pallidum (Tp) infection, we analyzed a series of 9 IPT-LN and 9 extranodal IPT (spleen, 4 cases; lung, orbit, gut, skin, and liver) for the presence of Tp, using a polyclonal antibody anti-Tp. At the time of biopsy, none of the patients was suspected for luetic infection, nor specific serologic tests were available. IPT-LN areas extensively involved the nodal parenchyma in 4 cases, whereas they were focal in the remaining 5 cases. Capsular thickening and inflammation (6/9), venulitis (3/9), small granulomas (3/9), and follicular hyperplasia (7/9) were observed in the associated lymphoid parenchyma. Tp were detected in 4/9 cases of LN-IPT and in none of the extranodal IPT. Tp were extremely abundant within the IPT areas and in the perivascular tissues in the surrounding parenchyma, whereas they were scattered within the capsule. In Tp+ cases, marked follicular hyperplasia was the single distinctively associated feature. Double immunostains revealed that Tp were predominantly contained in the cytoplasm of CD11c+ CD163+ macrophages, some of which co-expressed HLA-DR. In addition, scattered S100+ interdigitating dendritic cells also showed intracytoplasmic Tp. This study shows that a significant number of IPT-LN is associated with Tp infection. A spirochetal etiology can be suspected in cases of IPT-LN, independently from the extension of the lesions, especially when pronounced follicular hyperplasia is found. Infection by Tp of macrophages and dendritic cells are in keeping with in vitro data and indicate that immune mediated mechanisms may be involved in the pathogenesis of the lesions.

Gastrointestinal malignancies in HIV-infected or immunosuppressed patients: pathologic features and review of the literature

The gastrointestinal (GI) tract is a common internal organ to be involved by human immunodeficiency virus (HIV)-related malignancies. It is the second most common site for Kaposi sarcoma after skin, and the commonest visceral site, for Kaposi sarcoma in AIDS patients. GI lymphomas have been documented in approximately 25% of AIDS patients with systemic lymphomas. Moreover, GI involvement of AIDS-lymphoma has been associated with poor prognosis and short survival. Several other malignancies that occur in the GI tract are also closely related to HIV-infected or immunosuppressed individuals; these include posttransplant lymphoproliferative disorder, Epstein-Barr virus-associated smooth muscle tumors, anal precancerous lesions, and squamous cell carcinoma. As a result of active antiretroviral therapy, patients infected with HIV are living longer and are consequently at increased risk for development of cancer. Therefore, it is possible that the number of AIDS-associated malignancies will rise and the pattern of tumors may change in the future. In this paper, the clinicopathologic features of GI malignancies associated with AIDS patients are reviewed and the differential diagnosis with other mimic lesions is discussed.

Inflammatory myofibroblastic tumors in the liver: MRI of two immunohistochemically-verified cases

In immunohistochemically-proven hepatic inflammatory myofibroblastic tumors, MRI revealed layered patterns of contrast enhancement during dynamic imaging, consisting of outer hypovascular rind and inner hypervascular stroma and mimicking the imaging features of pyogenic organized abscess with deficient central necrosis in four lesions in two patients. For the outer hypovascular rind, T2-weighted images showed hyperintensity, suggesting immature fibrosis corresponding to the area of arterial hypovascularity and delayed contrast enhancement. The patients' favorable clinical course and imaging findings reflected the benign nature of these lesions, from an infectious origin, despite the phenotypic expression of myofibroblastic proliferation in the hypervascular stroma containing chronic inflammatory cells.

Cryptococcal Inflammatory Pseudotumors

"Inflammatory pseudotumors" (IPTs) embrace a heterogeneous spectrum of reactive, infective, and neoplastic entities, that are characterized by a clinical mass composed of a histologic proliferation of spindle cells in a background of inflammatory cells and collagen fibers. Although a spectrum of microorganisms have been identified in infective IPTs, mycobacterial infective IPTs are reported most commonly. We document 5 solitary cryptococcal IPTs, in 2 males and 3 females, aged 19 to 43 years, in the soft tissues of the anterior chest wall, thigh, and arm. All were HIV-positive and had been treated for disseminated cutaneous and/or meningeal cryptococcosis with antifungal therapy, 6 to 12 months earlier. The specimens demonstrated a storiform arrangement of plump spindle cells, in addition to spindle and polygonal cells that were arranged in a haphazard manner. Background lymphocytes, plasma cells, and fibrosis were noted, in addition to scattered giant cells and focal necrosis. On high-power examination, Cryptococcus neoformans yeasts were identified within and between vacuolated spindle and polygonal cells on routine and special stains, confirming cryptococcal IPTs. Immunophenotyping of the spindle cells confirmed a mixed histiocytic and myofibroblastic lineage, with a predominance of the former. In documenting 5, hitherto unreported, pseudotumoral spindle cell reactions to C. neoformans, we not only highlight the need for intense appraisal of all IPTs for infective agents on routine and special stains and investigations, but also postulate that a complex host-fungus interaction, coupled with an exuberant, myofibroblastic response to incomplete therapy, are the pathogenetic drive for the pseudotumoral presentation.

Plasma cell granuloma associated with pulmonary actinomycosis: a case report

Plasma cell granuloma (PCG) of the lung is a rare disease that usually presents as a pulmonary nodule or mass on incidental radiographic examination without symptoms. Although the etiology of PCG is still controversial, many findings have lent support to the lesion being a reactive inflammatory process rather than a neoplastic one. We describe a 53-yr-old male who presented with a hemoptysis and have a lung mass at the left upper lobe on chest radiograph. The lung mass was primarily diagnosed as PCG by percutaneous needle aspiration and biopsy, and the patient was treated with oral steroid because he and relatives refused the operation. However, the size of the lung mass did not change and open thoracotomy and lobectomy were done therefore. He was confirmed as having pulmonary actinomycosis with PCG after surgery. To our knowledge, this is the first report of PCG associated with actinomycosis in Korea.

Intramandibular inflammatory myofibroblastic tumor--a true neoplasm or reactive lesion?

OBJECTIVE

Inflammatory myofibroblastic tumor (IMT) is an uncommon lesion reported to arise in various organs and by convention believed to be a nonneoplastic reactive inflammatory condition. Because of its radiographic and histologic similarities to malignancy, IMT can pose a considerable diagnostic dilemma. The purpose of this study is to report the first intramandibular IMT and to discuss the possible nature of this lesion.

STUDY DESIGN

Detailed documentation of clinical, radiographic, and histologic features; literature review.

RESULTS

This lesion showed distinct radiographic, histologic, and immunohistochemical features. The lesion recurred 14 months after initial removal with almost identical histology.

CONCLUSION

This is the first documented case of an intramandibular IMT. Due to the rarity of these lesions, their clinical sequelae and prognosis are undetermined. As a result of specific immunohistochemical phenotyping and clinical behavior of this lesion, we favored a diagnosis of inflammatory myofibroblastic tumor. Wide excision with a long-term clinical follow-up is required.

Oral inflammatory myofibroblastic tumor demonstrating ALK, p53, MDM2, CDK4, pRb, and Ki-67 immunoreactivity in an elderly patient

Inflammatory myofibroblastic tumor (IMT) is a controversial lesion composed of myofibroblasts, accompanied by varying numbers of inflammatory cells. Various pathogenetic factors have been proposed (ie, reactive, infectious, autoimmune, and neoplastic) but the etiology of most IMTs remains unknown. Here we review the literature of oral IMTs, detailing the demographic profile of these rare lesions. Moreover, we present an unusual case of IMT arising from the mandibular alveolar mucosa of an 82-year-old female. Microscopic examination revealed plump spindle cells set in a myxoid vascular stroma admixed with inflammatory cells. Numerous large ganglion cell-like cells were seen, some exhibiting emperipolesis of neutrophils. Ultrastructurally, prominent myofibroblasts with abundant rough endoplasmic reticulum were noted. Tumor cells were immunoreactive for vimentin, smooth muscle actin, and KP1 (CD68), and negative for desmin, S-100, and EBV-LMP. The lesion was excised without margins and the patient has manifested no evidence of disease at an 18-month recall. In an attempt to further delineate the potential neoplastic nature of this lesion, we assessed the immunohistochemical expression of various markers that have been linked to neoplastic transformation. The recorded positivity for ALK, p53, MDM2, CDK4, pRb, and Ki-67, despite the absence of bcl-2 reactivity, strongly favors the neoplastic origin of the studied tumor.

Application of horizontal staircase electrophoresis in agarose minigels to the random intergenic spacer analysis of clinical samples

The random intergenic spacer analysis is a recently developed technique for the study of microbial populations. The bacterial intergenic spacer (ITS) is located between 16S rRNA and 23S rRNA genes and presents different length and sequence among bacterial species. Therefore, the amplicons can be separated by electrophoresis commonly performed at low voltage during several hours. Although this technique is especially useful for unculturable microorganisms, it has not been applied before to clinical sample analysis. As these samples have a limited number of bacterial species, the size of the gels may be reduced to facilitate their handling and to reduce the running time. To obtain maximum separation among the ITS bands, we analysed in this work different electrophoretical conditions including staircase electrophoresis, a technique based on the application of several voltage steps. The results obtained showed a different behaviour of the electrical resistance during the performance of submarine horizontal and vertical staircase electrophoresis. In the first case the resistance decreased during most of the running time whereas in the second case it increased. Here, we show that the performance of horizontal staircase electrophoresis reduces the running time more than 80% with respect to conventional electrophoresis at low voltages. This procedure was applied to the separation of ITS bands from bacterial DNA present in a tissue from a vocal cord biopsy. The sequencing of these bands allowed their identification. This new procedure may be very useful in the rapid diagnosis of bacteria present in human, animal and plant tissues.

Inflammatory myofibroblastic tumor with ALK/TPM3 fusion presenting as ileocolic intussusception: an unusual presentation of an unusual neoplasm

Inflammatory myofibroblastic tumor is a rare spindle cell lesion of indeterminate malignant potential occurring in both pulmonary and extrapulmonary tissues. This report describes an unusual presentation of an unusual tumor at an unusual location: an intramural ileal case of inflammatory myofibroblastic tumor presenting with intussusception in a 29-year-old woman. We characterize this tumor through microscopic and ultrastructural analysis, extensive immunohistochemical analysis, ploidy analysis, and Epstein-Barr virus in situ hybridization, and we report the finding of an ALK/TPM3 fusion using fluorescence in situ hybridization.

Mesenteric inflammatory pseudotumor as a cause of abdominal pain in a teenager: presentation and literature review

Inflammatory pseudotumor (IP) is an unusual cause of chronic abdominal pain in children. The management of these lesions is complicated by controversies surrounding their appropriate classification and the numerous alternate names with which they are described. Successful treatment requires careful radiologic and pathologic evaluation to distinguish IPs from other lesions, along with complete surgical resection. We present the case of a 15-year-old boy with IP and review the literature in an attempt to simplify the description of these tumors.

[Inflammatory pseudotumor of lymph node]

INTRODUCTION

Inflammatory pseudotumor of lymph node is a rare case in the etiology of fever of unknown origin.

OBSERVATION

We report the observation of a woman, aged 40, hospitalized with intermittent fever revealing under-diaphragm adenopathy related to inflammatory pseudotumor of lymph node.

CONCLUSION

Inflammatory pseudotumor of lymph node is a rare pathology whose nosological definition is unclear. It should probably be considered as belonging to a category different from the inflammatory pseudotumor of other organs. The diagnosis presents itself in case of isolated adenopathy or prolonged fever and is based on an anatomopathology that essentially calls to mind a lymphoma. The evolution of the condition is shown to be favorable : it can lead to a spontaneous remission, or call for a non-steroid anti-inflammatory treatment, or a steroid therapy.

Inflammatory pseudotumor of the liver in a patient with congenital granulocytopenia and HCV infection

Inflammatory pseudotumor (IPT) of the liver is a rare pathologic lesion. Although IPTs within the liver shows spontaneous regression, these lesions are frequently misdiagnosed as malignant on the basis of the clinical manifestation and the results of diagnostic imaging. With special regard to magnetic resonance imaging (MRI), differential diagnosis such as hepatocellular or cholangiocellular carcinoma (HCC/CCC) as well as regenerative liver lesions are discussed in a case of IPT with concomitant hepatitis C virus (HCV) infection and congenital granulocytopenia.

Inflammatory pseudotumor of the spleen with EBV positivity: report of a case

Inflammatory pseudotumor (IPT) of the spleen is a rare benign tumor with unknown etiology. It causes problems in the diagnosis because of mimicking some hematopoetic malignancies. Here we report the case of a 36-yr-old woman complaining of nausea and insomnia. Laboratory investigations were limited to increase of leukocyte and thrombocyte count. Ultrasonography and magnetic resonance (MR) imaging showed circumscribed solid lobulated mass, measuring about 6.5 cm in diameter, located in the dorsal region of the spleen. Splenectomy was performed with the differential diagnosis including hamartoma and lymphoma of the spleen. Histological examination of the sharply demarcated splenic mass consisted of myofibroblasts and admixture of inflammatory cells. Immunohistochemistry and in situ hybridization were performed. IPT of the spleen was diagnosed. Epstein-Barr virus (EBV) was detected in the tumor by in situ hybridization. This rare entity is presented because of its clinical, radiological and pathological difficulties in the differential diagnosis.

Follicular dendritic reticulum cell tumor mimicking inflammatory pseudotumor of the spleen

In the course of a routine clinical check up of the 54 year old male a splenic well circumscribed tumor like mass of 12 cm in diameter was discovered. Splenectomy with removal of splenic hilar lymph nodes and liver wedge biopsy were performed. Four years later the patient is symptom free. In the removed spleen the tumor like lesion showed a pattern consistent with the diagnosis of inflammatory pseudotumor. However, besides lymphocytes, plasma cells, macrophages, eosinophils and myofibroblasts a high number of slightly polymorphic, frequently binucleated cells positive for CD21 and CD23 were seen. These cells which were scattered or formed smaller or larger groups and fascicles were considered to represent follicular dendritic reticulum cells (FDRCs) and the lesion a FDRC tumor. Flow cytometric DNA ploidy analysis showed a hyperdiploid cell population inside the tumor like lesion. Besides FDRC tumors of high and of intermediate malignancy the present case may represent a low grade type of moderate proliferation activity. The FDRCs of the lesion and a few smaller spindle cells were EBER positive indicative of the presence of EBV. No EBER positive cells were seen in the uninvolved spleen.

Oligoclonal T-cell populations in an inflammatory pseudotumor of the pancreas possibly related to autoimmune pancreatitis: an immunohistochemical and molecular analysis

Inflammatory pseudotumors (IPT), also known as inflammatory myofibroblastic tumors (IMT), are benign inflammatory processes that may have an infectious etiology and are very rare in the pancreatico-biliary region. Recent studies suggest a biological distinction between IPT and IMT, the latter being a true neoplastic process. We describe a case of pancreatic IPT, originally diagnosed as malignancy, which presumably recurred 4 months after the operation. Histologically, the tumor consisted of a smooth muscle actin and CD68-positive spindle cell population and a more abundant mononuclear inflammatory cell population, primarily composed of macrophages and T-lymphocytes. Inflammatory cells were the source of connective tissue growth factor and transforming growth factor-beta1 and tended to accumulate around nerves and blood vessels, as well as around residual pancreatic parenchymal elements, where an intense angiogenetic response was detected. Comparative genomic hybridization analysis of the tumor showed no chromosomal imbalances. Polymerase chain reaction-based analysis of T-cell receptor gamma gene rearrangement revealed an oligoclonal pattern. These findings suggest that the pathogenesis of aggressive cases of IPT could be related to the development of an intense and self-maintaining immune response, with the emergence of clonal populations of T-lymphocytes. The relation of the pancreatic IPT to autoimmune pancreatitis is emphasized.

Congenital multifocal inflammatory pseudotumor: a case report

Inflammatory pseudotumor is an uncommon benign tumor found in various sites throughout the body. The etiology is unclear with evidence to support both neoplastic and infective processes. The authors present a case with several unique features. It represents the first reported case detected antenatally. The tumor was found separately within the abdomen and thorax. The thoracic component of the tumor was managed without resection or ablative treatment but showed spontaneous regression.

Gemella bacteraemia characterised by 16S ribosomal RNA gene sequencing

AIMS

To define epidemiology, clinical disease, and outcome of gemella bacteraemia by 16S rRNA gene sequencing. To examine the usefulness of the Vitek, API, and ATB systems in identifying two gemella species.

METHODS

All alpha haemolytic streptococci other than Streptococcus pneumoniae isolated from blood cultures during a six year period were identified by conventional biochemical methods, the Vitek system, and the API system. 16S rRNA gene sequencing was performed on all isolates identified by both kits as gemella with >or= 95% confidence or by either kit as any bacterial species with < 95% confidence. The ATB expression system was used to identify the two isolates that were defined as gemella species by 16S rRNA gene sequencing.

RESULTS

Of the 302 alpha haemolytic streptococci other than S pneumoniae isolated, one was identified as Gemella morbillorum, and another as Gemella haemolysans by 16S rRNA gene sequencing. The patient with monomicrobial G morbillorum bacteraemia was a 66 year old man with community acquired infective endocarditis with septic thromboemboli. The patient with G haemolysans bacteraemia was a 41 year old woman with hospital acquired polymicrobial bacteraemia during the neutropenic period of an autologous bone marrow transplant for non-Hodgkin's lymphoma, the first case of its kind in the English literature. The API and ATB expression systems only identified the second strain as G haemolysans at 94% and 99% confidence, respectively, whereas the Vitek system identified none of the two strains correctly at > 70% confidence.

CONCLUSIONS

Gemella bacteraemia is uncommon. 16S rRNA gene sequencing is the method of choice for identification of gemella and gemella-like isolates.

Usefulness of the MicroSeq 500 16S ribosomal DNA-based bacterial identification system for identification of clinically significant bacterial isolates with ambiguous biochemical profiles

Due to the inadequate automation in the amplification and sequencing procedures, the use of 16S rRNA gene sequence-based methods in clinical microbiology laboratories is largely limited to identification of strains that are difficult to identify by phenotypic methods. In this study, using conventional full-sequence 16S rRNA gene sequencing as the "gold standard," we evaluated the usefulness of the MicroSeq 500 16S ribosomal DNA (rDNA)-based bacterial identification system, which involves amplification and sequencing of the first 527-bp fragment of the 16S rRNA genes of bacterial strains and analysis of the sequences using the database of the system, for identification of clinically significant bacterial isolates with ambiguous biochemical profiles. Among 37 clinically significant bacterial strains that showed ambiguous biochemical profiles, representing 37 nonduplicating aerobic gram-positive and gram-negative, anaerobic, and Mycobacterium species, the MicroSeq 500 16S rDNA-based bacterial identification system was successful in identifying 30 (81.1%) of them. Five (13.5%) isolates were misidentified at the genus level (Granulicatella adiacens was misidentified as Abiotrophia defectiva, Helcococcus kunzii was misidentified as Clostridium hastiforme, Olsenella uli was misidentified as Atopobium rimae, Leptotrichia buccalis was misidentified as Fusobacterium mortiferum, and Bergeyella zoohelcum was misidentified as Rimerella anatipestifer), and two (5.4%) were misidentified at the species level (Actinomyces odontolyticus was misidentified as Actinomyces meyeri and Arcobacter cryaerophilus was misidentified as Arcobacter butzleri). When the same 527-bp DNA sequences of these seven isolates were compared to the known 16S rRNA gene sequences in the GenBank, five yielded the correct identity, with good discrimination between the best and second best match sequences, meaning that the reason for misidentification in these five isolates was due to a lack of the 16S rRNA gene sequences of these bacteria in the database of the MicroSeq 500 16S rDNA-based bacterial identification system. In conclusion, the MicroSeq 500 16S rDNA-based bacterial identification system is useful for identification of most clinically important bacterial strains with ambiguous biochemical profiles, but the database of the MicroSeq 500 16S rDNA-based bacterial identification system has to be expanded in order to encompass the rarely encountered bacterial species and achieve better accuracy in bacterial identification.

Two splenic lesions in need of clarification: hamartoma and inflammatory pseudotumor

This short review is dedicated to a precise pathologic characterization of 2 uncommon and poorly defined lesions of the spleen and to their distinction from histologically similar processes. Splenic hamartoma represents an abnormally formed red pulp and is characterized by the presence of sinus-like structures lined by CD8(+) endothelia. The great variety of its morphologic appearances may result from the preponderant growth of one or another of the several components of the red pulp, ie, CD34(+) capillaries, myoid cells and macrophages. Therefore, it is proposed that "cord capillary hemangioma," myoid angio-endothelioma, and histiocyte-rich tumors are part of the spectrum of splenic hamartoma. Inflammatory pseudotumor (IPT) of the spleen is a reactive lesion, probably of multiple etiologies, characterized by a mixture of inflammatory cells and a minor, disorganized component of spindle cells. The latter include fibroblasts, SMA(+) myofibroblasts, and CD68(+) spindled histiocytes, establishing a close similarity with the IPT of the lymph node. This benign process needs to be distinguished from 2 others that have a predominant spindle cell component arranged in parallel bundles: the IPT-like follicular dendritic cell tumor, which is consistently associated with Epstein-Barr Virus; and the inflammatory myofibroblastic tumor, also often Epstein-Barr Virus-related and similar to those of the soft tissues, lung and other organs. These 2 lesions are neoplastic and therefore have a potentially worse prognosis than IPT.

Inflammatory pseudotumor of the spleen in a 6-year-old child: a clinicopathologic study

Inflammatory pseudotumors of the spleen are extremely rare in children. To our knowledge, only 3 cases of splenic inflammatory pseudotumors have been reported. An inflammatory pseudotumor of the spleen was found incidentally during the workup of vesicoureteral reflux disease in a 6-year-old girl. The clinical, pathologic, immunophenotypic, and molecular features and the differential diagnostic features are discussed here. Splenic inflammatory pseudotumors, although rare, should be considered in the differential diagnosis of a mass lesion of the spleen in children.

Pseudobacteraemia in a patient with neutropenic fever caused by a novel paenibacillus species: Paenibacillus hongkongensis sp. nov

AIMS

To characterise a strain of Gram negative aerobic straight or slightly curved rods (HKU3) isolated from the blood culture of a 9 year old Chinese boy with neutropenic fever and pseudobacteraemia.

METHODS

The isolate was phenotypically investigated by standard biochemical methods using conventional biochemical tests, scanning electron microscopy, and transmission electron microscopy. Genotypically, the 16S rRNA gene of the bacterium was amplified by the polymerase chain reaction (PCR) and sequenced. The sequence of the PCR product was compared with known 16S rRNA gene sequences in the Genbank by multiple sequence alignment. The G + C content was determined by thermal denaturation. A phylogenetic tree was constructed by the PileUp method.

RESULTS

The cells of the bacterial strain were aerobic, sporulating, Gram negative straight or slight curved rods. The bacterium grew on horse blood agar as non-haemolytic, grey colonies of 1 mm in diameter after 24 hours of incubation at 37 degrees C in ambient air. No enhancement of growth was seen in 5% CO(2). It grew at 50 degrees C as pinpoint colonies after 72 hours of incubation, but did not grow at 65 degrees C or on MacConkey agar. It was non-motile. It produced catalase (weakly positive) and cytochrome oxidase. It reduced nitrate, produced beta galactosidase, hydrolysed esculin, and utilised sodium acetate. A scanning electron micrograph of the bacterium showed straight or slightly curved rods. A transmission electron micrograph of the cell wall of the bacterium revealed multiple electron dense layers, including the outer membrane, middle murein layer, and inner cytoplasmic membrane, compatible with its Gram smear appearance. 16S rRNA gene sequencing showed that there were 7.7%, 8.0%, 8.2%, and 8.6% differences between the 16S rRNA gene sequence of the bacterium and those of Paenibacillus macerans, Paenibacillus borealis, Bacillus ehimensis, and Paenibacillus amylolyticus, respectively. The mean (SD) G + C content of the bacterium was 47.6 (2.1) mol%. Phylogenetically, it belongs to the genus paenibacillus (previously called group 3 bacillus).

CONCLUSIONS

A bacterium that exhibited phenotypic and genotypic characteristics that are very different from closely related members of paenibacillus was the cause of pseudobacteraemia in a patient with neutropenic fever. A new species, Paenibacillus hongkongensis sp. nov. is proposed, for which HKU3 is the type strain.

Analysis of a viridans group strain reveals a case of bacteremia due to lancefield group G alpha-hemolytic Streptococcus dysgalactiae subsp equisimilis in a patient with pyomyositis and reactive arthritis

Streptococcus dysgalactiae is classified by a combination of phenotypic and genotypic characteristics into Lancefield group C alpha-hemolytic Streptococcus dysgalactiae subsp. dysgalactiae and Lancefield group C, group G, and group L beta-hemolytic Streptococcus dysgalactiae subsp. equisimilis. In this study, we report the isolation of a catalase-negative, alpha-hemolytic, optochin- and bacitracin-resistant viridans group strain, which does not grow in 10 or 40% bile, on MacConkey agar or bile esculin agar, or in 6% NaCl, from the blood culture of a 73-year-old woman with pyomyositis and poststreptococcal reactive arthritis. Lancefield grouping revealed that the strain was a group G streptococcus. The Vitek system (GPI) showed that it was unidentified, and the API system (20 STREP) showed that it was 95.7% S. dysgalactiae subsp. dysgalactiae. 16S rRNA gene sequencing showed that it was a strain of S. dysgalactiae. Based on phylogenetic affiliation with 16S rRNA gene or GroEL amino acid (another bacterial gene, in addition to 16S rRNA gene, that is highly conserved) sequences, the strain is most closely related to Lancefield group C beta-hemolytic S. dysgalactiae subsp. equisimilis. PCR amplification and sequencing of the streptolysin S structural gene (sagA) and M protein gene (emm) hypervariable region showed the presence of these suspected primary virulence factors. Further studies would delineate whether the isolate is just a hemolysin-deficient variant of group G beta-hemolytic S. dysgalactiae subsp. equisimilis or a novel type of S. dysgalactiae. The present case showed that group G alpha-hemolytic S. dysgalactiae subsp. equisimilis can be associated with serious invasive infection and poststreptococcal sequelae.

Single gene target bacterial identification. groEL gene sequencing for discriminating clinical isolates of Burkholderia pseudomallei and Burkholderia thailandensis

Proper identification of Burkholderia pseudomallei and Burkholderia thailandensis is crucial in guiding clinical management of patients with suspected melioidosis, as more than 99% of cases of melioidosis are caused by B. pseudomallei, whereas B. thailandensis is only responsible for causing less than 1% of the cases. However, the difference between the 16S ribosomal RNA gene sequences of B. pseudomallei and that of B. thailandensis is only 1%, and is therefore not discriminative enough for distinguishing the 2 species confidently. In this study, we amplified and sequenced the groEL genes of 7 strains of B. thailandensis and 6 strains of B. pseudomallei, and compared the sequences with 7 other groEL gene sequences of Burkholderia species. BLAST analysis revealed that the putative protein encoded by the groEL gene of B. thailandensis has 99.6%, 99.5%, 98.4%, 98.5%, and 96.5% amino acid identity with the groEL of B. pseudomallei, B. mallei, B. cepacia, B. vietnamiensis, and B. fungorum respectively. The amino acid sequences of GroEL of the strains of B. thailandensis and B. pseudomallei all showed >99.5% amino acid identity with each other. The nucleotide sequence of the groEL gene of any of the strains of B. thailandensis showed >99.8% nucleotide identity with that of any of the other strains of B. thailandensis, and the nucleotide sequence of the groEL gene of any of the strains of B. pseudomallei showed >99.5% nucleotide identity with that of any of the other strains of B. pseudomallei. However, the nucleotide sequence of any of the strains of B. thailandensis showed <97.6% nucleotide identity with any of the strains of B. pseudomallei. The amino acid sequences of GroEL of the 20 strains of Burkholderia species all showed >96% amino acid identity with each other. Furthermore, the nucleotide sequence of the groEL genes of the 2 strains of B. cepacia showed >99.5% nucleotide identity with each other, and the nucleotide sequence of the groEL gene of B. mallei showed >99.5% nucleotide identity with any of the strains of B. pseudomallei. The groEL gene sequence is therefore good for distinguishing between B. thailandensis and B. pseudomallei, and the GroEL amino acid and groEL nucleotide sequences of this single gene locus may potentially be useful for a 2-tier hierarchical identification of medically important Burkholderia at the genus and species levels respectively.

Catheter-related Microbacterium bacteremia identified by 16S rRNA gene sequencing

We describe the application of 16S rRNA gene sequencing in defining two cases of catheter-related Microbacterium bacteremia. In the first case, a gram-positive bacillus was isolated from both the blood culture and central catheter tip of a 39-year-old woman with chronic myeloid leukemia. The API Coryne system identified the isolate as 98.9% Aureobacterium or Corynebacterium aquaticum. In the second case, a gram-positive bacillus was recovered from five sets of blood cultures from both central catheter and percutaneous venipuncture of a 5-year-old girl with acute myeloid leukemia. The isolate was identified by the API Coryne system as 99.7% Cellulomonas or Microbacterium species. Further phenotypic tests failed to identify the two isolates. 16S rRNA gene sequencing showed 99.4% similarity between the first isolate and Microbacterium oxydans and 98.7% similarity between the second isolate and Microbacterium trichotecenolyticum, indicating that both isolates were Microbacterium species. Microbacterium infections are rarely reported in the literature. Although the central venous catheter was previously proposed to be a source of bacteremia, the first case in this report represents the first culture-documented case of catheter-related Microbacterium bacteremia.

Diagnosis of pelvic actinomycosis by 16S ribosomal RNA gene sequencing and its clinical significance

Traditional ways of identification of anaerobic Gram-positive non-sporulating bacilli by isolation of the organism and studying it phenotypically by elucidation of its morphologic and biochemical characteristics and metabolic end products are associated with a need for special equipment and expertise, and strains that are "unidentified" because of ambiguous biochemical profiles. In this study, an anaerobic Gram-positive non-sporulating bacterium was isolated from the intrauterine contraceptive device of a 36-year old woman with pyosalpinx. The Vitek system (ANI) showed that it was 99% Propionibacterium granulosum; whereas the API system (20A) showed that it was 78% Actinomyces meyeri/odontolyticus. The 16S ribosomal RNA gene of the strain was amplified and sequenced. There was 0 base difference between the isolate and A. odontolyticus (GenBank Accession no. AJ234047), indicating the isolate most closely resembled a strain of A. odontolyticus. Identification of the organism in this study was important because the duration of antibiotic therapy would be entirely different. In the present case, identification of the bacterium as A. odontolyticus inferred that the patient suffered from an intermediate form of pelvic actinomycosis. A prolonged course of antibiotics would be more desirable, as the relapse rate of actinomycosis after a short course of antibiotics is high.

Epstein-Barr virus-associated smooth muscle tumour: a distinctive mesenchymal tumour of immunocompromised individuals

immunosuppressed patients are predisposed to the development of smooth muscle tumours which show near consistent association with Epstein-Barr virus (EBV). This report describes a 37-year-old patient with acquired immunodeficiency syndrome who initially presented with two masses in the liver. Image-guided core biopsy revealed a spindle cell tumour with histological and immunological features of smooth muscle neoplasm which was shown by in situ hybridisation for EBV early RNAs to be EBV-associated. The literature on this uncommon entity is critically reviewed and the differential diagnosis is also discussed.

Identification by 16S ribosomal RNA gene sequencing of Arcobacter butzleri bacteraemia in a patient with acute gangrenous appendicitis

AIMS

To identify a strain of Gram negative facultative anaerobic curved bacillus, concomitantly isolated with Escherichia coli and Streptococcus milleri, from the blood culture of a 69 year old woman with acute gangrenous appendicitis. The literature on arcobacter bacteraemia and arcobacter infections associated with appendicitis was reviewed.

METHODS

The isolate was phenotypically investigated by standard biochemical methods using conventional biochemical tests. Genotypically, the 16S ribosomal RNA (rRNA) gene of the bacterium was amplified by the polymerase chain reaction (PCR) and sequenced. The sequence of the PCR product was compared with known 16S rRNA gene sequences in the GenBank by multiple sequence alignment. Literature review was performed by MEDLINE search (1966-2000).

RESULTS

The bacterium grew on blood agar, chocolate agar, and MacConkey agar to sizes of 1 mm in diameter after 24 hours of incubation at 37 degrees C in 5% CO2. It grew at 15 degrees C, 25 degrees C, and 37 degrees C; it also grew in a microaerophilic environment, and was cytochrome oxidase positive and motile, typically a member of the genus arcobacter. Furthermore, phenotypic testing showed that the biochemical profile of the isolate did not fit into the pattern of any of the known arcobacter species. 16S rRNA gene sequencing showed one to two base differences between the isolate and A butzleri, but 35 to 39 base differences between the isolate and A cryaerophilus, indicating that the isolate was a strain of A butzleri. Only three cases of arcobacter bacteraemia with detailed clinical characteristics were found in the English literature. The sources of the arcobacter species in the three cases were largely unknown, although the gastrointestinal tract is probably the portal of entry of the A butzleri isolated from the present case because the two concomitant isolates (E coli and S milleri) in the blood culture were common flora of the gastrointestinal tract. In addition, A butzleri has previously been isolated from the abdominal contents or peritoneal fluid of three patients with acute appendicitis.

CONCLUSIONS

16S rRNA gene sequencing was useful in the identification of the strain of A butzleri isolated from the blood culture of a patient with acute gangrenous appendicitis. Arcobacter bacteraemia is rare. Further studies using selective medium for the delineation of the association between A butzleri and acute appendicitis are warranted.