Moraxella catarrhalis induces CEACAM3-Syk-CARD9-dependent activation of human granulocytes

The human restricted pathogen Moraxella catarrhalis is an important causal agent for exacerbations in chronic obstructive lung disease in adults. In such patients, increased numbers of granulocytes are present in the airways, which correlate with bacteria-induced exacerbations and severity of the disease. Our study investigated whether the interaction of M. catarrhalis with the human granulocyte-specific carcinoembryonic antigen-related cell adhesion molecule (CEACAM)-3 is linked to NF-κB activation, resulting in chemokine production. Granulocytes from healthy donors and NB4 cells were infected with M. catarrhalis in the presence of different inhibitors, blocking antibodies and siRNA. The supernatants were analysed by enzyme-linked immunosorbent assay for chemokines. NF-κB activation was determined using a luciferase reporter gene assay and chromatin-immunoprecipitation. We found evidence that the specific engagement of CEACAM3 by M. catarrhalis ubiquitous surface protein A1 (UspA1) results in the activation of pro-inflammatory events, such as degranulation of neutrophils, ROS production and chemokine secretion. The interaction of UspA1 with CEACAM3 induced the activation of the NF-κB pathway via Syk and the CARD9 pathway and was dependent on the phosphorylation of the CEACAM3 ITAM-like motif. These findings suggest that the CEACAM3 signalling in neutrophils is able to specifically modulate airway inflammation caused by infection with M. catarrhalis.

[Melioidosis-like disease: infection with Burkholderia cocovenenans as rare differential diagnosis for Lymphadenitis colli]

INTRODUCTION

Neoplasms, autimmune disorders and infectious diseases as differential diagnoses of cervical lymphadenopathies also require the consideration of rare causes.

CASE REPORT

A 25-year-old patient presented for further diagnosis and treatment of a colliquating, high febrile cervical lymphadenopathy. The patient from Thailand who had been living in Germany for 8 years reported she worked as rice farmer during the 1980s. Examination showed a vast physical condition with severe weight loss, joint- and swallowing aches which did not respond to high doses of parenteral antibiotic treatment. The histology of a lymph node revealed a necrotizing lymphadenitis, lymphoma were excluded. During further complications (sepsis, splenic and intracerebral abscesses and osteomyelitis) multiple different cytologic samples from lympoid tissue, different wound lesions and bronchial secretion microscopically showed non-fermenting, gram-negative rods by 16S-rDNA-analysis identified as Burkholderia cocovenenans/gladioli. Thus a melioidosis-like disease (endemic in south east asia) was diagnosed. Responsible for the severe course with a lethal recurrence despite antibiotic treatment was the patients additional immune defect (anti-interferone-gamma-autoantibodies).

SUMMARY

Travelling history informations become more and more important considering increasing long-distance travelling and worldwide migration movements. Unclear inflammatory/infectious diseases require early interdisciplinary treatment. Detailed informations for the pathologist facilitate the diagnosis.

Chronic periodontal disease is associated with single-nucleotide polymorphisms of the human TLR-4 gene

Periodontitis is an inflammatory disease affecting the connective tissue surrounding the teeth leading to tooth loss. Pathogens associated with periodontitis interact with Toll-like receptors (TLRs) to induce cytokines causing and aggravating disease. We screened 197 individuals suffering from generalized periodontitis for the presence of Asp299Gly and Thr399Ile of TLR-4 as well as Arg753Gln of TLR-2 in comparison to matched controls. Single-nucleotide polymorphisms (SNPs) of TLR-4 were elevated among patients (odd's ratio 3.650, 95% CI 1.573-8.467, P < or = 0.0001), while no difference was observed for TLR-2. TLR-4 SNPs were correlated with chronic periodontitis (odd's ratio 5.562, 95% CI 2.199-14.04, P < or = 0.0001), but not with aggressive periodontitis. This observation was confirmed employing a group of periodontally healthy probands over 60 years of age. These data demonstrate that genetic variants of TLR-4 may act as risk factors for the development of generalized chronic periodontitis in humans.

Misidentification of Mycobacterium leprae as Mycobacterium intracellulare by the COBAS AMPLICOR M. intracellulare test

Commercially available nucleic acid probe- and amplification-based systems for detection and differentiation of mycobacteria are widely used in clinical microbiology laboratories. Here we report two cases of human leprosy in which the COBAS AMPLICOR Mycobacterium intracellulare test led to false- positive results. Correct identification of Mycobacterium leprae was possible only by amplification and comparative sequence analysis of the 16S rRNA gene.

Treponema putidum sp. nov., a medium-sized proteolytic spirochaete isolated from lesions of human periodontitis and acute necrotizing ulcerative gingivitis

So far, little phenotypic heterogeneity has been detected in cultured oral treponemes with trypsin-like proteolytic activity, and all have been assigned to the species Treponema denticola. However, comparisons of protein patterns and antigen expression in our collection of proteolytic oral treponemes occasionally identified isolates with a unique phenotype; e.g. strain OMZ 830 (=ATCC 700768), which qualified as a ‘pathogen-related oral spirochaete’ due to the presence of a ∼37 kDa protein reactive with the Treponema pallidum FlaA-specific mAb H9-2. In addition to such single isolates, a homogeneous group of seven independent strains is described that were highly motile, medium-sized, proteolytic but asaccharolytic spirochaetes and were cultured from human gingivitis, periodontitis and acute necrotizing ulcerative gingivitis in medium OMIZ-Pat supplemented with 1 % human serum and antibiotics. Growth of these spirochaetes in OMIZ-Pat was not dependent on, but was stimulated by, human or bovine serum. Carbohydrates were neither required nor stimulatory for growth. The protein and antigen patterns of total cell extracts of these organisms separated by SDS-PAGE were distinct from those of all previously cultured spirochaetes, with highest similarity to T. denticola. The novel spirochaete has a 2 : 4 : 2 arrangement of the periplasmic flagella, similar to T. denticola. However, the flagellin pattern as detected by immunostaining or glycan staining of Western blots readily distinguished the novel group from T. denticola. Also, distinct from reference strains of T. denticola, none of the novel isolates displayed sialidase or dentilisin activities, both of which are expressed by most strains of T. denticola. Trypsin-like activity and other enzymes as detected by API ZYM test were similar to those of T. denticola. The status of a novel species is supported by the 16S rRNA gene sequence, with 98·5 % similarity to its closest cultured relative, T. denticola. The name Treponema putidum sp. nov. is proposed (type strain OMZ 758T=ATCC 700334T=CIP 108088T).

A case of septicemia with Pediococcus acidilactici after long-term antibiotic treatment

Presented here is a case of septicemia caused by an uncommon, multiresistant, gram-positive microorganism (Pediococcus acidilactici) after long-term antibiotic treatment. Pediococcus spp. are rarely cultivated from clinical specimens, and species differentiation is difficult due to the paucity of phenotypic traits. In this case, a polyphasic approach consisting of phenotypic and molecular genetic analyses was used, and the identification of Pediococcus acidilactici was conclusive. Precise identification and antimicrobial susceptibility testing of rarely isolated bacteria are required in order to provide adequate treatment to infected patients and to determine the pathogenic role of these organisms.

A novel technique for monitoring the development of bacterial biofilms in human periodontal pockets

A new technique is presented for analyzing subgingival bacterial plaque. Different materials (polytetrafluoroethylene, gold, dentin) kept for several days in periodontal pockets of patients suffering from periodontitis were analyzed by electron microscopy and fluorescence in situ hybridization (FISH). Those parts of the carriers extending into the deepest zone of the pockets were predominantly colonized by spirochetes and Gram-negative bacteria whereas those segments in contact with a shallower region were colonized by streptococci. Independent of the material used, the bacterial colonization of the carriers appears to be similar. FISH using eubacteria- and species-specific oligonucleotides on semi-thin cross-sections of the carriers in combination with confocal laser scanning microscopy allowed detailed analysis of the architecture of biofilms and identification of putative periodontal pathogens with single cell resolution.

Chemotaxis in pathogenic spirochetes: directed movement toward targeting tissues?

Chemotaxis is an important feature of motile organisms that allows navigation through various environments. It enables them to detect nutrients and to avoid unfavorable or dangerous conditions. Motility and chemotaxis are widely acknowledged as important virulence factors for pathogenic bacteria. In this review, we try to explore the role of chemotaxis in the pathogenesis of spirochetes. Chemotaxis might be involved in tissue identification and penetration, and represents a possible mechanism for evasion of the host's immune defense. The recent development of genetic tools for pathogenic spirochetes and "tracking" techniques, employing fluorescent in situ hybridization (FISH), could revolutionize our understanding of the importance of chemotaxis for infection and persistence of these bacteria in their host.

Phylogenetic analysis of rhizosphere-associated beta-subclass proteobacterial ammonia oxidizers in a municipal wastewater treatment plant based on rhizoremediation technology

In wastewater treatment plants based on the rhizosphere zone (rhizoremediation technology), ammonia-oxidizing bacteria (AOB) play an important role in the removal of fixed nitrogen. However, the diversity of these bacteria in rhizoremediation wastewater treatment plants is largely unknown. We employed direct PCR amplification and cloning of 16S rRNA genes to determine the phylogenetic affiliation of AOB occurring in root and soil samples of a wastewater treatment plant (Merzdorf plant, Brandenburg, Germany). 16S rDNA clone libraries were screened by hybridization using an oligonucleotide probe specific for AOB of the beta subclass of proteobacteria. Comparative sequence analysis of all hybridization-positive clones revealed that the majority of rDNA sequences was affiliated to members of the genus Nitrosospira and formed a novel subcluster (SM cluster), whereas only three sequences were most closely related to Nitrosomonas species. Affiliation of the novel Nitrosospira-like sequences with those of isolates from soil and rhizosphere suggests that phylogenetic clusters reflect physiological differences between members of this genus.

Fluorescence in situ hybridization (FISH) for direct visualization of microorganisms

As a technique allowing simultaneous visualization, identification, enumeration and localization of individual microbial cells, fluorescence in situ hybridization (FISH) is useful for many applications in all fields of microbiology. FISH not only allows the detection of culturable microorganisms, but also of yet-to-be cultured (so-called unculturable) organisms, and can therefore help in understanding complex microbial communities. In this review, methodological aspects, as well as problems and pitfalls of FISH are discussed in an examination of past, present and future applications.

Treponema lecithinolyticum sp. nov., a small saccharolytic spirochaete with phospholipase A and C activities associated with periodontal diseases

Strong phospholipase A (PLA) and phospholipase C (PLC) activities as potential virulence factors are the outstanding characteristics of eight strains of small oral spirochaetes isolated from deep periodontal lesions. By qualitative dot-blot DNA-DNA hybridization and 16S rDNA sequence comparison, these spirochaetes form a distinct phylogenetic group, with Treponema maltophilum as its closest cultivable relative. Growth of these treponemes, cells of which contain two endoflagella, one at each pole, was autoinhibited by the PLA-mediated production of lysolecithin unless medium OMIZ-Pat was prepared without lecithin. N-Acetylglucosamine was essential and D-ribose was stimulatory for growth. All isolates were growth-inhibited when 1% foetal calf serum was added to the medium. Growth on agar plates supplemented with human erythrocytes produced haemolysis. In addition to PLA and PLC, the new isolates displayed strong activities of alkaline and acid phosphatases, beta-galactosidase, beta-glucuronidase, N-acetyl-beta-glucosaminidase and sialidase, intermediate activities of C4- and C8-esterases, naphthol phosphohydrolase and alpha-fucosidase and a distinctive 30 kDa antigen detectable on Western blots. This phenotypically and genotypically homogeneous group is proposed as a novel species, Treponema lecithinolyticum sp. nov., with isolate OMZ 684T designated as the type strain. A molecular epidemiological analysis using a T. lecithinolyticum-specific probe showed this organism to be associated with affected sites when compared with unaffected sites of periodontitis patients. This association was more pronounced in patients with rapidly progressive periodontitis than in those with adult periodontitis.

Cloning and characterization of a gene (mspA) encoding the major sheath protein of Treponema maltophilum ATCC 51939(T)

The major sheath protein-encoding gene (mspA) of the oral spirochete Treponema maltophilum ATCC 51939(T) was cloned by screening a genomic library with an anti-outer membrane fraction antibody. The mspA gene encodes a precursor protein of 575 amino acids with a predicted molecular mass of 62.3 kDa, including a signal peptide of 19 amino acids. The native MspA formed a heat-modifiable, detergent- and trypsin-stable complex which is associated with the outer membrane. Hybridization with an mspA-specific probe showed no cross-reactivity with the msp gene from Treponema denticola.

Treponema brennaborense sp. nov., a novel spirochaete isolated from a dairy cow suffering from digital dermatitis

A novel Treponema species was isolated from an ulcerative lesion of a cow suffering from digital dermatitis (DD), a disease which causes painful ulcerations along the coronary band. Among other anaerobic bacteria, high numbers of spirochaetes have been regularly found in DD lesions. Here data are presented of a spirochaete isolated from a DD ulcer. By chemotaxonomy, protein analysis and comparative 16S rDNA sequence analysis this isolate was classified as a treponeme that differed from all Treponema species described previously. The only isolate, DD5/3T, for which the name Treponema brennaborense is proposed, is designated the type strain of the novel species. The strain is a small, highly motile spirochaete that has two periplasmic flagella, one flagellum being attached at each cell pole. Strain DD5/3T exhibits alpha-glucosidase and N-acetyl-beta-glucosaminidase activity and growth is inhibited by rabbit serum. T. brennaborense was phylogenetically most closely related (89.5% 16S rRNA similarity) to Treponema maltophilum, an oral spirochaete isolated from a periodontitis patient.

Molecular epidemiology of oral treponemes associated with periodontal disease

Periodontitis, a disease responsible for tooth loss worldwide, is characterized by chronic inflammation of the periodontium, eventually leading to destruction of periodontal ligaments and supporting alveolar bone. Spirochetes, identified by dark-field microscopy as being the most predominant bacteria in advanced lesions, are thought to play a causative role. Various spirochetal morphotypes were observed, but most of these morphotypes are as yet uncultivable. To assess the role of these organisms we designed oligonucleotide probes for the identification of both cultivable and so far uncultivable spirochetes in periodontitis patients. Subgingival plaque specimens taken from diseased sites (n = 200) and healthy control sites (n = 44) from 53 patients with rapidly progressive periodontitis (RPP) were submitted to direct in situ hybridization or dot blot hybridization after prior amplification with eubacterial primers. Spirochetes were found in all patients, but their distributions varied considerably. Parallel use of oligonucleotide probes specific for cultivable or so far uncultivable treponemes suggested the presence of novel yet unknown organisms at a high frequency. These uncultivable treponemes were visualized by fluorescence in situ hybridization, and their morphologies, sizes, and numbers could be estimated. All RPP patients included in this study harbored oral treponemes that represent either novel species, e.g., Treponema maltophilum, or uncultivable phylotypes. Therefore, it is necessary to include these organisms in etiologic considerations and to strengthen efforts to cultivate these as yet uncultivable treponemes.

[Diagnostic value of protected bronchoalveolar lavage in HIV-associated pneumonia]

OBJECTIVE

The concept of the protected bronchoalveolar lavage (PBAL) is to improve the diagnostic yield in bacterial pneumonia by unifying the high sensitivity of bronchoalveolar lavage (BAL) and specificity of the protected specimen brush (PSB). HIV-infected patients have been shown to have a high incidence of bacterial pneumonia as well as bacterial colonisation of the tracheobronchial tree. We therefore studied the value of PBAL in this population.

METHODS

During a period of twelve months 40 episodes in 36 patients with symptoms suggestive of pneumonia were investigated retrospectively. In all cases without infiltrates on chest radiograph a CT-scan of the chest was performed. Patients without infiltrates also in CT-scan served as controls. Bronchoscopic investigation included a PSB and a PBAL in the same lung segment most prominently affected. Microbiological workup was performed for bacterial agents, mycobacteria, fungi, viruses and parasites. Quantitative cultures for bacteria were considered significant in case of > or equal to 10(3) cfu/ml in PSB and > or equal to 10(4) cfu/ml in PBAL.

RESULTS

32 episodes in 28 patients were identified as pneumonia. A definite diagnosis could be established in 19/32 (59%) of cases. Bacteria accounted for 10/19 (53%). Pneumocystis carinii for 9/19 (47%) of cases including one case that revealed mixed infection with Streptococcus pneumoniae and Pneumocystis carinii. Another pneumonia was due to Aspergillus fumigatus. The sensitivity for bacterial pneumonia was 44% for PSB and 56% for PBAL, the specificity 100%. The overall diagnostic accuracy was 60% and 68%, respectively. The yield for Pneumocystis carinii was 8/9 (89%).

CONCLUSIONS

PBAL as compared to PSB had a superior diagnostic yield for bacterial pneumonia. As PBAL additionally conserved the yield of BAL reported for Pneumocystis carinii, it may represent a rational diagnostic technique for pneumonia in HIV-infected patients.