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Analysis of 71 strains of Neisseriaceae by starch-gel electrophoresis of hexokinase, phosphoglucomutase, glucose phosphate isomerase, and L-malate-nicotinamide adenine dinucleotide phosphate oxidoreductase showed that all gonococci and all memingococci have a characteristic hexokinase isoenzyme that is specific for each species and clearly distinguishes meningococci and gonococci from each other and from other species of Neisseriaceae. Strains of gonococci that were transformed into maltose utilizers by DNA from Neisseria lactamica and Neisseria meningitidis showed no change in the isoenzymes so that they could still be differentiated from meningococci and other Neisseriaceae by isoenzyme electrophoresis. In view of the limited sensitivity and specificity of conventional tests for the identification of gonococci and the possibility that gonococci may be transformed into maltose utilizers by DNA from normal throat flora, electrophoresis of hexokinase isoenzymes should be useful for the precise laboratory identification of the pathogenic neisseriae, especially those from atypical sites and those giving indeterminate reactions.
Fast and reliable identification of microbial isolates is a fundamental goal of clinical microbiology. However, in the case of some fastidious gram-negative bacterial species, classical phenotype identification based on either metabolic, enzymatic, or serological methods is difficult, time-consuming, and/or inadequate. 16S or 23S ribosomal DNA (rDNA) bacterial sequencing will most often result in accurate speciation of isolates. Therefore, the objective of this study was to find a hypervariable rDNA stretch, flanked by strongly conserved regions, which is suitable for molecular species identification of members of the Neisseriaceae and Moraxellaceae. The inter- and intrageneric relationships were investigated using comparative sequence analysis of PCR-amplified partial 16S and 23S rDNAs from a total of 94 strains. When compared to the type species of the genera Acinetobacter, Moraxella, and Neisseria, an average of 30 polymorphic positions was observed within the partial 16S rDNA investigated (corresponding to Escherichia coli positions 54 to 510) for each species and an average of 11 polymorphic positions was observed within the 202 nucleotides of the 23S rDNA gene (positions 1400 to 1600). Neisseria macacae and Neisseria mucosa subsp. mucosa (ATCC 19696) had identical 16S and 23S rDNA sequences. Species clusters were heterogeneous in both genes in the case of Acinetobacter lwoffii, Moraxella lacunata, and N. mucosa. Neisseria meningitidis isolates failed to cluster only in the 23S rDNA subset. Our data showed that the 16S rDNA region is more suitable than the partial 23S rDNA for the molecular diagnosis of Neisseriaceae and Moraxellaceae and that a reference database should include more than one strain of each species. All sequence chromatograms and taxonomic and disease-related information are available as part of our ribosomal differentiation of medical microorganisms (RIDOM) web-based service (http://www.ridom.hygiene.uni-wuerzburg.de/). Users can submit a sequence and conduct a similarity search against the RIDOM reference database for microbial identification purposes.
Bacterial transferrin receptors that have been described in the families Pasteurellaceae and Neisseriaceae are composed of two receptor proteins, transferrin binding proteins 1 and 2 (Tbp1 and Tbp2). In contrast, bacterial lactoferrin receptors have only been described for human pathogens in the family Neisseriaceae, and were believed to consist of a single protein, Lbp1, which is highly homologous to Tbp1. We describe a modified affinity isolation procedure that facilities isolation of a second lactoferrin receptor protein Lbp2 (a presumptive Tbp2 homologue) from Neisseria meningitidis, Moraxella catarrhalis and Moraxella bovis using immobilized lactoferrin. Antiserum specific for either the M. catarrhalis Tbp1+2 molecules, the M. catarrhalis Lbp1 molecule, or for a commercial preparation of human lactoferrin did not react on western blots with the same organisms' affinity purified Lbp2. In addition, the M. catarrhalis Lbp2 could be isolated in a functional form without contaminating Lbp1 or Tbp1+2. We also demonstrate that the bovine pathogen, M. bovis, produces functional transferrin and lactoferrin receptors specific for the bovine forms of these glycoproteins. A putative lbpB gene, recently speculated to reside immediately upstream of the N. meningitidis Lbp1 structural gene, lbpA, likely encodes the newly isolated Lbp2 protein from this bacterial species.
The study of antigenic interrelations in the family Neisseriaceae resulted in the isolation of 2 main immunologically separated variants of protein complexes: the first variant was characteristic of nonpathogenic and pathogenic species of the genus Neisseria as well as of 7 taxonomically undefined Neisseria species (N. lactamicus, N. cuniculi, N. ellongata, N. ovis, N. animalis, N. cinerea, N. canis) and Gemella haemolysans; the second variant was represented by the genera Branhamella and Acinetobacter. N. caviae and 3 out of 14 Neisseria strains of undefined species had no common antigens with the genera Neisseria and Branhamella. The importance of the immunotyping of protein complexes for studying the problems connected with the taxonomy of the family Neisseriaceae was considered.
Lipopolysaccharides from 5 different genera of the Neisseriaceae were analyzed on sodium dodecylsulfate-polyacrylamide gel electrophoresis, and visualized by silver staining. Significant heterogeneity in the banding patterns was observed with some of the strains producing only low molecular mass molecules and others producing O-repeating units. All genera examined except Branhamella contained strains that were able to produce an O-repeating side chain on their lipopolysaccharides. The ability to produce the repeating subunit did not correlate with the presence of plasmids.
On the basis of nucleic acid relationships, the family Neisseriaceae consists of the genera Neisseria, Kingella, Simonsiella and of Alysiella filiformis, Eikenella corrodens, and the CDC groups EF-4 and M-5. Differentiation, especially of the new members of the family, by conventional phenotypic characteristics is difficult and in some cases leads to doubtful results. On the other hand, cellular components proved to be suitable for the characterization of bacterial taxa. We investigated the cellular carbohydrates derived from whole cell hydrolysates of the above mentioned taxa with the exception of Neisseria by gas chromatography/mass-spectrometry. The analysis revealed characteristic patterns for all taxa considered, although with some species of which only few strains were investigated so far only preliminary results could be established. With the method used, the carbohydrate analysis could be completed within six hours starting from a pure culture. All strains investigated exhibited a common pattern with ribose, arabinose, glucose, and galactose. Qualitative and quantitative differences in contents of fucose, sorbose, rhamnose, threose, heptose, galactosamine and an amino sugar similar to glucosamine discriminated members of the taxa investigated. To achieve a taxonomically precise differentiation of the species investigated by conventional phenotypic features as available in commercial rapid test kits, these tests should be completed by the carbohydrate analysis technique presented.
Fourteen human periodontal isolates recovered from a purported Eikenella corrodens-selective medium containing 1 microgram of clindamycin per ml displayed biochemical traits which differed from those described for E. corrodens. These organisms were gram-negative rods which corroded agar. The isolates were oxidase positive and urease, indole, and esculin negative. They differed from E. corrodens in catalase, nitrate reduction, lysine decarboxylase, and ornithine decarboxylase activities. One isolate, strain UB-294, was presumptively identified as Kingella denitrificans. A second isolate, strain UB-204, differed from E. corrodens by being catalase positive and nitrate reduction negative. Twelve isolates, including strain UB-38T (T = type strain), were phenotypically similar to Kingella kingae except that they did not produce acid from maltose and were not beta-hemolytic. Essentially complete (1,480-base) 16S rRNA sequences were determined for strains UB-38T, UB-204, and UB-294 and the type strains of Neisseria animalis, Neisseria canis, Neisseria denitrificans, Neisseria elongata, Neisseria flavescens, Neisseria macaca, and Neisseria polysaccharea. These sequences were compared with the previously published sequences of six other species belonging to the family Neisseriaceae. On the basis of the results of the comparative sequence analysis, UB-294 was confirmed as a K. denitrificans strain, UB-204 was identified as a member of a new species which may belong in the genus Eikenella, and UB-38T was identified as a member of a new species of the genus Kingella, for which we propose the name Kingella oralis [corrected]. Since strain UB-204 was the only representative of a new species, it was not named.(ABSTRACT TRUNCATED AT 250 WORDS)
Forty-five strains classified in the family Neisseriaceae were analysed for wax esters by gas-liquid chromatography. The amounts and types of waxes varied between the taxa. Waxes were not detected in 16 strains of 'true neisseriae' (genus Neisseria) or in two strains of Kingella, but they were found in all 'false neisseriae', in all species of Moraxella except Moraxella phenylpyrouvica, in five out of 10 strains of Acintobacter, and in all strains of a group of psychrophilic, oxidase-positive organisms. The chain lengths of the wax esters ranged from C24 to C42, with C36 predominating. In all taxa, esters with even numbers of carbon atoms constituted 70 to 100% of the total. Saturated, mono-unsaturated and diunsaturated waxes were found. Acinetobacter strains were characterized by large amounts (30 to 98%) of di-unsaturated wax esters; such waxes did not exceed 8% in the 'false neisseriae' or Moraxella spp. Waxes of strains belonging to the psychrophilic, oxidase-positive group generally resembled those found in Moraxella. Wax esters with odd numbers of carbon atoms were abundant in M. lacunata (29%), M. atlantae (15%) and in the psychorophilic group (19 to 28%); long-chain esters (C40 or above) were characteristic of M. atlantae (30%) and one strain of M. osloensis (26%).
The lectin slide agglutination test for Neisseria gonorrhoeae has been modified and improved. Results show that wheat germ agglutinin and soybean lectin agglutinate 100% (193 of 193 tested) of clinical isolates of N. gonorrhoeae. Lectin-reactive meningococci can be readily identified by the hydrolysis of gamma-glutamyl-beta-naphthylamide. Branhamella catarrhalis, Neisseria lactamica, Neisseria sicca, Neisseria subflava, Neisseria perflava, and meningococcal serogroups A, B, C, X, Y, and Z do not interfere with the positive identification of N. gonorrhoeae. The frequently encountered problem of autoagglutination of members of the family Neisseriaceae may be circumvented by a short treatment of cellular suspensions with DNase. Based on agglutination assays, the enzyme treatment did not result in a loss of wheat germ agglutinin receptors from the bacteria. The lectin agglutination test, coupled with the gamma-glutamyl aminopeptidase assay, is proposed as a rapid and accurate means of identifying clinical isolates of gonococci.
Dihydrofolate reductases of five species of the family Neisseriaceae were compared by means of inhibition profiles, using several structurally different inhibitors, including trimethoprim (TMP) and pyrimethamine. All enzymes were seen to be highly susceptible to the folate analog aminopterin, but exhibited moderate susceptibility to all other inhibitors tested. Approximately 200-fold higher concentrations of TMP were needed to inhibit neisserial reductases as compared to the E. coli enzyme. Besides poor penetration this is assumed to be the main basis for the low susceptibility of neisseriae to TMP. In addition to TMP all other inhibitors were also moderately active or inactive in vitro. The enzymatic differences, as seen from inhibition profiles, were statistically significant but small among all species of the genus Neisseria. Branhamella catarrhalis on the other hand was seen to be far less related to the other neisseriae, as seen by the inhibition profile of its reductase, its dihydrofolate reductase conttent, as well as by its in vitro properties.
Members of the family Neisseriaceae (554 strains) were screened for gamma-glutamyl-transferase (gamma GT) activity. gamma GT was produced by Neisseria meningitidis but not produced by any strain of N. gonorrhoeae, N. lactamica and Branhamella catarrhalis. Most non-proteolytic Acinetobacter calcoaceticus produced gamma GT whereas most A. lwoffii failed to produce gamma GT.
The cellular fatty acids of seventeen Acinetobacter strains were determined. Most acids identified were previously found in neisseriae and moraxellae. Specific for Acinetobacter was 2-hydroxydodecanoid acid and a few minor unidentified components. The fatty acid data were analysed by numerical methods and compared with previous results obtained for neisseriae and moraxellae. The findings were consistent with genetic evidence for some affinities of genus Acinetobacter to genus Moraxella and "false neisseriae". Occasionally, a high resemblance in fatty acid pattern was demonstrated between a Moraxella strain and certain strains of Acinetobacter, and also between an Acinetobacter strain and certain "true neisseriae". Still, the acinetobacters constituted one single cluster separated from the other genera of Neisseriaceae.
The immunological characteristics of protein complexes isolated from the filtrates of broth cultures, obtained after prolonged incubation, of 86 strains of N. perflava, N. flava, N. subflava, N. Flaviscens, N. sica and N. mucosa are presented. All these strains, irrespective of their species, had 11--15 common antigens and differed by 1--4 components. The presence of common antigens in all representatives of the family Neisseriaceae has been proved to be important for the study of immunological reactivity to this group of microorganisms.
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Branhamella catarrhalis and other commensal Neisseria species were isolated from 200 out of 500 sputum samples from patients with lower respiratory tract (LRT) infections at the Lagos University Teaching Hospital (LUTH). B. catarrhalis was isolated from 60 (12%). The isolation rates for other Neisseria species were as follows: N. mucosa from 45 (9%), N. sicca from 40 (8%), N. lactamica from 35 (7%), N. cinerea from 12 (2.4%) and N. subflava from 8 (1.6%). B. catarrhalis occurred in pure cultures in 15 (25%) of the 60 samples positive for this organism. Twenty (33%) out of the 60 N. catarrhalis isolates were beta-lactamase positive.
IgA proteases are extracellular enzymes of bacteria that have human immunoglobulin A of the IgA1 subclass as their only known substrate. The identification of this enzyme in neisseria prompted us to determine whether IgA protease production correlates with pathogenicity within this genus. Multiple clinical isolates of Neisseria gonorrhoeae, N. meningitidis and eight species of non-pathogenic neisseria that commonly colonize the normal human nasopharynx were examined for IgA protease activity. All N. gonorrhoeae and N. meningitidis strains were enzyme positive; all non-pathogenic strains were negative. Among meningococci, the enzyme occurred in strains carried harmlessly in the nasopharynx as well as those isolated from systemic infections. Because mucosal immune defense is largely mediated by antibodies of the IgA isotype, the finding that IgA protease activity is linked specifically to the pathogenic neisseria suggests that the enzyme may be involved in the pathogenesis of neisserial infection.
Neisseria elongata subsp. glycolytica strain 6171/75 is closely similar to the type strain of N. elongata, M2, as regards DNA base composition, fatty acid content and electrophoretic mobility of two glutamate dehydrogenases, one of which showed a reaction of identity with the corresponding enzyme from M2 in double immunodiffusion in agar. The strain showed genetic homologies with strain M2 in genetic transformation at a level suggesting species identity, and with N. meningitidis at a lower level. No affinity to Moraxella species or "false neisseriae" was demonstrated, with the exception of a production of a few transformants in the 6171/75 recipient by DNA from Kingella kingae. The strain showed the same pattern of associated variation of colony type, fimbriation and competence in transformation as that found in other Neisseria and Moraxella species. After continuous subcultivation for some time some clones of the strain appeared to have lost the ability to produce acid from glucose.