This paper examines tourist perceptions of the potential for the elimination of travel agencies in the presence of the Internet. The opinions of 413 tourists on making transactions through both Internet‐based (hereafter, online) and traditional distribution channels were analysed. Experimental results illustrated that tourists still used professional services and advice offered by travel agencies. Tourists also agreed that more information could be found through the Internet. Following the findings, the paper suggests that both online and traditional distributional channels can coexist in the future.

A bacterium was isolated from the blood and empyema of a cirrhotic patient. The cells were facultatively anaerobic, nonsporulating, gram-negative, seagull shaped or spiral rods. The bacterium grows on sheep blood agar as nonhemolytic, gray colonies 1 mm in diameter after 24 h of incubation at 37°C in ambient air. Growth also occurs on MacConkey agar and at 25 and 42°C but not at 4, 44, and 50°C. The bacterium can grow in 1 or 2% but not 3, 4, or 5% NaCl. No enhancement of growth is observed with 5% CO 2 . The organism is aflagellated and nonmotile at both 25 and 37°C. It is oxidase, catalase, urease, and arginine dihydrolase positive, and it reduces nitrate. It does not ferment, oxidize, or assimilate any sugar tested. 16S rRNA gene sequencing showed that there are 91 base differences (6.2%), 112 base differences (7.7%), and 116 base differences (8.2%) between the bacterium and Microvirgula aerodenitrificans, Vogesella indigofera, and Chromobacterium species, respectively. The G؉C content (mean and standard deviation) is 68.0% ؎ 2.43%, and the genomic size is about 3 Mb. Based on phylogenetic affiliation, the bacterium belongs to the Neisseriaceae family of the ␤-subclass of Proteobacteria. For these reasons, a new genus and species, Laribacter hongkongensis gen. nov., sp. nov., is proposed, for which HKU1 is the type strain. Further studies should be performed to ascertain the potential of this bacterium to become an emerging pathogen.Since the discovery of PCR and DNA sequencing, comparison of the gene sequences of bacterial species has shown that the 16S rRNA gene is highly conserved within a species and among species of the same genus and hence can be used as the new gold standard for the identification of bacteria to the species level. Using this new standard, phylogenetic trees based on base differences between species can be constructed, and bacteria can be classified and reclassified into new genera (7,8). Furthermore, noncultivable organisms and organisms with ambiguous biochemical profiles can be classified and identified (10, 11). Recently, this technique was used for the identification of a strain of Mycobacterium neoaurum with ambiguous biochemical and whole-cell fatty acid profiles isolated from a patient with acute lymphoblastic leukemia (18), a strain of Escherichia coli with an ambiguous biochemical profile isolated from a bone marrow transplant recipient (16), a strain of Enterobacter cloacae with an ambiguous biochemical profile isolated from a renal transplant recipient (14), a strain of tube coagulase-negative Staphylococcus aureus isolated from a patient with refractory anemia with excessive blasts in transformation (19), a strain of Arcobacter cryaerophilus isolated from a traffic accident victim (13), and a noncultivable strain of Pseudomonas veronii from a patient with a pseudotumor (3).In this study, we report the isolation of a bacterial strain from the blood and empyema of a cirrhotic patient. The strain, named HKU1, exhibited phenotypic characteristics that do not fit into the patter...

Streptococcus iniae, a fish pathogen causing infections in aquaculture farms worldwide, has only been reported to cause human infections in North America. In this article, we report the first two cases of invasive S. iniae infections in two Chinese patients outside North America. While the first patient presented with bacteremic cellulitis, which is the most common presentation in previous cases, the second patient represents the first recognized case of S. iniae osteomyelitis. Both S. iniae strains isolated from the two patients were either misidentified or unidentified by three commercial systems and were only identified by 16S rRNA gene sequencing. Since no currently available commercial system for bacterial identification includes S. iniae in its database, 16S rRNA gene sequencing is the most practical and reliable method to identify the bacterium at the moment. In contrast to the distinct genetic profile described previously in clinical isolates from Canada, the present two isolates and a clinical isolate from a Canadian patient were found to be genetically unrelated, as demonstrated by pulsed-field gel electrophoresis. Morphologically, colonies of both isolates were also larger, more beta-hemolytic and mucoid, which differ from the usual morphotype described for S. iniae. Owing to their habit of cooking and eating fresh fish, the Asian population is strongly associated with S. iniae infections. As a result of the difficulty in making microbiological diagnosis in patients with cellulitis and the problem of identification in most clinical microbiology laboratories, the prevalence of S. iniae infections, especially in the Asian population, may have been under-estimated.

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.Identification of bacteria in clinical microbiology laboratories is traditionally performed by isolation of the organisms and study of their phenotypic characteristics, including Gram staining, morphology, culture requirements, and biochemical reactions. However, these methods of bacterial identification have major drawbacks. First, they cannot be used for noncultivable organisms. Second, we are occasionally faced with organisms exhibiting biochemical characteristics that do not fit into patterns of any known genus and species. Third,...

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 . 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°C in 5% CO 2 . It grew at 15°C, 25°C, and 37°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.T he identification of bacteria in the clinical microbiology laboratory is traditionally performed by the isolation of the organism and the study of its phenotypic characteristics, including Gram staining, morphology, cultural requirements, and biochemical reactions, which have been the gold standard of bacterial identification. However, these methods of bacterial identification have two major drawbacks. First, they cannot be used for non-cultivable organisms and, second, organisms with biochemical characteristics that do not fit into the patterns of any known genus and species pose diagnostic problems."The 16S ribosomal RNA gene is hig...

We have performed Monte Carlo calculations t.o determine the charge accumulation on &reading edge dislocations in GaN as a function of the dislocation density and background dopant density. Four possible core structures have been examined, each of which produces defect levels in the gap and may therefore act as electron or hole traps. Our results indicate that charge accumulation, and the resulting electrostatic interactions, can change the relative stabilities of the different. core structures. Structures having Ga and N vacancies at the dislocation core are predicted to be st.able under nitrogen-rich and gallium-rich growth conditions, respectively. Due to dopant depletion at. high dislocat.ion density and the rnult.itude of charge states, the line charge exhibits complex crossover behaxior as the dopant. and dislocat.ion densities vary.Gallium nit,ride films grown on sapphire substrates t y p ically contain bet.ween lo8 and 1O'O threading dislocations per cm2 as a result* of the subst,ant,ial film-substrate chemical and 1att.ice mismatch.l Nevertheless, it. has been possible t.0 fabricate bright and efficient light,-emitt.ing diodes from films composed of GaN alloyed wit.h InN and A1N.2 This success led several researchers t.o specu1at.e early on t.hat t.hreading dislocat.ions in GaN might not act. as efficient. minority-carrier recombination sit.es.' Recent. experiment.al studies, however, have confirmed that there is significant opt.ica13 and elect.rica14 activity associat,ed with these defects. In particular, results from a recent. scanning-capacit.ance microscopy study5 suggest that dislocations are negatively charged in n-type GaN, and studies of transverse mobility in n-type GaN indicate that elect,rons are scattered from these negatively charged dislocations.Recent, charge-st,ate calculations for AlN and GaN' indicate that threading edge disloqations produce defect levels in the forbidden energy gap. These calculations provide estimat.es for these defect. levels. In agreement wit.h experiment.al studies, edge dislocations are predicted to be negatively charged in n-type GaN. However, the amount of charge accumulation could not be quantified because electrostatic interactions between charged defect sites and between defect. sites and ionized dopants were not included in the calculations. In this study, we treat coulomb interactions explicitly and therefore are able t.o predict. the amount. of charge accumulation on an edge dislocation under a variety of doping condit.ions.We examine t.he zero-temperature behavior of threading dis1ocat.ions using simulat,ed annealing.' The simulat.ion cell conbains one dislocation and is of lateral dimension u::' 2 , where u& is t.he dislocation densit.y. Elect.rons, modelled as point charges, can t.ransfer bet,ween dopants (donors or accept,orsf and defect. leveis at. t.he dislocat.ion cores, and among the dopants themselves. The dislocat,ion consists of 50-1000 defect sit.es situated 5.185A apart. We have examined the four dislocat.ion core st,ruct.ures previously cons...

A bacterium was isolated from the blood culture of a patient with infective endocarditis. The cells were facultative anaerobic, nonsporulating, gram-positive cocci arranged in chains. The bacterium grows on sheep blood agar as alpha-hemolytic, gray colonies of 0.5 to 1 mm in diameter after 24 h of incubation at 37°C in ambient air. Growth also occurs in 10 or 40% bile and on bile esculin agar but not in 6% NaCl. No enhancement of growth is observed in 5% CO 2 . It is nongroupable with Lancefield groups A, B, C, D, F, or G antisera and is resistant to optochin and bacitracin. The organism is aflagellated and is nonmotile at both 25 and 37°C. It is Voges-Proskauer test positive. It produces leucine arylamidase and ␤-glucosidase but not catalase, urease, lysine decarboxylase, or ornithine decarboxylase. It hydrolyzes esculin and arginine. It utilizes glucose, lactose, salicin, sucrose, pullulan, trehalose, cellobiose, hemicellulase, mannose, maltose, and starch. 16S rRNA gene sequencing showed that there were 3.6, 3.7, 4.3, 4.7, and 5.9% differences between the 16S rRNA gene sequence of the bacterium and those of Streptococcus gordonii, Streptococcus intermedius, Streptococcus constellatus, Streptococcus sanguis, and Streptococcus anginosus, respectively. The G؉C content of it (mean ؎ standard deviation) was 53.0% ؎ 2.9%. Based on phylogenetic affiliation, it belongs to the mitis or anginosus group of Streptococcus. For these reasons a new species, Streptococcus sinensis sp. nov., is proposed, for which HKU4 is the type strain. Further studies should be performed to ascertain the potential of this bacterium to become an emerging cause of infective endocarditis.Since the discovery of PCR and DNA sequencing, comparison of the gene sequences of bacterial species showed that the 16S rRNA gene is highly conserved within a species and among species of the same genus, and hence it can be used as the new gold standard for speciation of bacteria. Using this new standard, phylogenetic trees, based on base differences between species, are constructed, and bacteria are classified and reclassified into new genera (9, 10). Furthermore, noncultivable organisms and organisms with ambiguous biochemical profiles can be classified and identified (11,12). Recently we have reported the use of this technique for the identification of bacterial strains with ambiguous biochemical profiles (14,15,16,19,23), species that are rarely encountered clinically (6,18,20), and a bacterium that is noncultivable (2); discovery of a novel clinical syndrome (22) and a novel genus and species (24); and characterization of beta-hemolytic Lancefield group G streptococcal bacteremia (21).In this study, we report the isolation of a bacterial strain from the blood culture of a patient with infective endocarditis. The strain, named HKU4, exhibited phenotypic characteristics that do not fit into patterns of any known species. 16S rRNA gene sequencing showed that there was only 96.4% base identity between the 16S rRNA gene of HKU4 and that of the most closely r...

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