A total of 45 strains of black‐pigmented bacteroides, including Bacteroides melaninogenicus subsp. melaninogenicus, Bacteroides melaninogenicus subsp. intermedius and Bacteroides melaninogenicus subsp. asaccharolyticus, have been examined for morphological and physiological characteristics. They were also tested for the range of acidic metabolites, the typical basic amino acid of the mucopeptide, the base composition of DNA, the electrophoretic mobility of malate dehydrogenase and the susceptibility to certain antibiotics. The subspecies most commonly isolated from supragingival human dental plaque are B. melaninogenicus subsp. intermedius and B. melaninogenicus subsp. melaninogenicus. A list of tests for the differentiation of the three subspecies is given, but the separation of B. melaninogenicus subsp. asaccharolyticus from the other two subspecies of B. melaninogenicus is nevertheless recommended.

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Various subspecies of Bacteroides melaninogenicus differ in their pigmentation. Subsp. asaccharolyticus produces protohaem almost exclusively, subsp. intermedicus both protohaem and a smaller proportion of protoporphyrin, and subsp. melaninogenicus mainly protoporphyrin with a trace of protohaem. As a consequence young colonies can be differentiated by their red fluorescence in u.v. light (365nm): subsp. asaccharolyticus does not fluoresce, subsp. intermedicus shows a limited fluorescence, and subsp. melaninogenicus shows a bright fluorescence. The pigments were isolated as the dimethyl esters of protohaemin and of protoporphyrin and identified by electronic spectroscopy, mass spectrometry and comparisons by t.l.c. Incorporation of delta-aminolaevulinate into these pigments was not detected, nor was porphobilinogen formation observed. Subsp. melaninogenicus grown in the presence of [14C]protohaemin formed [14C]protoporphyrin. This appears to represent a novel biological demetallation.

During the 2010−11 summer outbreak of ostreid herpesvirus 1 (OsHV-1) in New Zealand, an opportunistic longitudinal field study was conducted. OsHV-1 PCR-negative oyster spat (Crassostrea gigas) were relocated to an OsHV-1 PCR-positive area of the North Island of New Zealand that was experiencing juvenile oyster mortalities. Over a period of 13 d, spat were monitored for mortality, sampled for histopathology, and tested for the presence of OsHV-1 using real time PCR and Vibrio culture. Histopathology showed some evidence of tissue pathology; however, no consistent progressive pathology was apparent. Field mortalities were evident from Day 6 on. After 5 and 7 d of exposure, 83 and 100% of spat, respectively, tested positive for the virus by real time PCR. Vibrio species recovered during the longitudinal study included V. splendidus and V. aestuarianus. This study offers insight into the rapidity of onset and virulence of the virus in naïve oyster spat in New Zealand waters. KEY WORDS: Ostreid herpesvirus 1 · Vibrio · Crassostrea gigas Resale or republication not permitted without written consent of the publisherDis Aquat Org 109: 231-239, 2014 al. 1972). In 1999, Le Deuff and Renault undertook initial molecular characterisation of the virus infecting Pacific oysters (Le Deuff & Renault 1999). This was followed up by the identification of the first variant (OsHV-1 Var) (Arzul et al. 2001a,b) and subsequent whole-genome sequencing of the ostreid herpesvirus 1 (OsHV-1; GenBank AY509253) (Davison et al. 2005). Segarra et al. (2010) published sequencing data on the emergence of the now problematic microvariant (OsHV-1 µVar).Several studies have identified other pathogens associated with major OsHV-1 mortality events in Europe. Vibrio species, including V. splendidus, V. aestuarianus and V. harveyi, have been isolated in association with OsHV-1 mortalities , Dégremont 2011, Schikorski et al. 2011a. Whilst Vibrio species are likely to be opportunistic pathogens, the significance of regular detection in association with OsHV-1 should not be overlooked. The major oyster mortality events in Europe are considered to be multi-factorial, with OsHV-1, Vibrio species and environmental conditions (e.g. increased water temperatures) all believed to contribute (Sauvage et al. 2009, Segarra et al. 2010, De Decker & Saulnier 2011, De Decker et al. 2011.During the summer of 2010−11 in New Zealand, OsHV-1, Vibrio species and warm water temperatures appeared to contribute to the deaths of juvenile C. gigas on the North Island of New Zealand. During the mortality event, the oyster industry provided access to pre-planned movements of apparently healthy hatchery-reared spat to an oyster growing site on the North Island where oyster mortalities attributed to OsHV-1 were occurring. This provided a unique opportunity to conduct a longitudinal study. This paper describes the molecular characterisation of the New Zealand OsHV-1 virus and results of the longitudinal study. MATERIALS AND METHODS Longitudinal studyApproximately 17 0...

The accuracy of antimicrobial susceptibility data submitted by microbiology laboratories to national and international surveillance systems has been debated for a number of years. To assess the accuracy of data submitted to the World Health Organization by users of the WHONET software, the Centers for Disease Control and Prevention distributed six bacterial isolates representing key antimicrobial-resistance phenotypes to approximately 130 laboratories, all but one of which were outside of the United States, for antimicrobial susceptibility testing as part of the World Health Organization's External Quality Assurance System for Antimicrobial Susceptibility Testing. Each laboratory also was asked to submit 10 consecutive quality control values for several key organism-drug combinations. Most laboratories were able to detect methicillin (oxacillin) resistance in Staphylococcus aureus, high-level vancomycin resistance in Enterococcus faecium, and resistance to extended-spectrum cephalosporins in Klebsiella pneumoniae. Many laboratories, particularly those using disk diffusion tests, had difficulty in recognizing reduced susceptibility to penicillin in an isolate of Streptococcus pneumoniae. The most difficult phenotype for laboratories to detect was reduced susceptibility to vancomycin in an isolate of Staphylococcus epidermidis. The proficiency testing challenge also included a request for biochemical identification of a gram-negative bacillus, which most laboratories recognized as Enterobacter cloacae. Although only a small subset of laboratories have submitted their quality control data, it is clear that many of these laboratories generate disk diffusion results for oxacillin when testing S. aureus ATCC 25923 and S. pneumoniae ATCC 49619 that are outside of the acceptable quality control range. The narrow quality control range for vancomycin also proved to be a challenge for many of the laboratories submitting data; approximately 27% of results were out of range. Thus, it is important to establish the proficiency of laboratories submitting data to surveillance systems in which the organisms are tested locally, particularly for penicillin resistance in pneumococci and glycopeptide resistance in staphylococci.Resistance to a variety of antimicrobial agents is emerging in bacterial pathogens throughout the world (8,21,50). Increases in the prevalence of penicillin resistance in Streptococcus pneumoniae (13,36,39,47), methicillin resistance in Staphylococcus aureus (1, 3, 38), vancomycin resistance in enterococci (5, 9, 16, 28), extended-spectrum ␤-lactamase-production in enteric gram-negative bacilli (2, 18, 37), and fluoroquinolone resistance in Neisseria gonorrhoeae (17) are just a few examples of the rising problem of resistance documented by both national and international surveillance systems in the past few years. The antimicrobial susceptibility testing data collected by the various surveillance systems are generated in several different fashions. In some systems, bacterial isolates are sent to a central labo...