Exploring the signature gut and oral microbiome in individuals of specific Ayurveda prakriti

Diagnosis and treatment of various diseases in Ayurveda, the Indian system of medicine, relies on 'prakriti' phenotyping of individuals into predominantly three constitutions, kapha, pitta and vata. Recent studies propose that microbiome play an integral role in precision medicine. A study of the relationship between prakriti - the basis of personalized medicine in Ayurveda and that of gut microbiome, and possible biomarker of an individual's health, would vastly improve precision therapy. Towards this, we analyzed bacterial metagenomes from buccal (oral microbiome) and fecal (gut microbiome) samples of 272 healthy individuals of various predominant prakritis. Major bacterial genera from gut microbiome included Prevotella, Bacteroides and Dialister while oral microbiome included Streptococcus, Neisseria, Veilonella, Haemophilus, Porphyromonas and Prevotella. Though the core microbiome was shared across all individuals, we found prakriti specific signatures such as preferential presence of Paraprevotella and Christensenellaceae in vata individuals. A comparison of core gut microbiome of each prakriti with a database of 'healthy' microbes identified microbes unique to each prakriti with functional roles similar to the physiological characteristics of various prakritis as described in Ayurveda. Our findings provide evidence to Ayurvedic interventions based on prakriti phenotyping and possible microbial biomarkers that can stratify the heterogenous population and aid in precision therapy.

Carriage of Neisseria meningitidis and other Neisseria species among children and young adults in Paraguay

Introduction. Colonization by Neisseria meningitidis is the pre-requisite for the development of disease. We present the findings of a cross-sectional investigation onto the oropharyngeal carriage of N. meningitidis and Neisseria species in the population aged 3 to 21 in Paraguay.Aim. Carriage prevalence by age groups, risk factors associated with carriage, and phenotypic and genotypic characteristics of strains are described.Methodology. We collected 2011 oropharyngeal swabs from consenting participants aged 3-21 years. Infants were recruited at immunization clinics, and older children and young adults were identified at schools and universities. A single oropharyngeal swab was collected and processed for the identification and isolation of Neisseria. Additionally, participants, or their legal guardian if these were minors, were requested to fill a standardized questionnaire.Results. N. meningitidis was isolated in 42/2011 (2.1 %) participants, while other Neisseria spp. were identified in 306/2011 (15.2 %) subjects: N. cinerea and N. lactamica were identified in 39/2011 (1.9 %) and 43/2011 (2.2 %), respectively. Meningococcal strains belonged to ten different clonal complexes, of which six are associated with invasive disease (ST-32/ET5 complex, ST-11/ET37 complex, ST-103 complex, ST-167 complex, ST-35 complex and ST-41/44 complex/lineage 3).Conclusion. Prevalence of N. meningitidis carriage was low compared to that reported from other settings, however, the overall carriage of Neisseria spp. (including N. meningitidis) was comparable to meningococcal carriage prevalence reported in the literature. This study is the first of its kind conducted in Paraguay, and one of the few known in the Southern Cone of Latin America.

Neisseria weixii sp. nov., isolated from rectal contents of Tibetan Plateau pika (Ochotona curzoniae)

Three independent isolates (10022^T, 10 009 and 10011) of a novel catalase-positive, Gram-stain-negative coccus in the genus Neisseria were obtained from the rectal contents of plateau pika on the Qinghai-Tibet Plateau, PR China. Based on 16S rRNA gene sequence analysis, our newly identified organisms were most closely related to Neisseria iguanae, Neisseria flavescens and Neisseria perflava with similarities ranging from 98.02 to 98.45 %, followed by seven other species in the genus Neisseria. Phylogenetic analysis based on 16S rRNA and rplF genes showed that our three novel isolates group with members of the genus Neisseria. Results of the average nucleotide identity (ANI) analysis confirmed that our isolates are of the same species, and the ANI values between type strain 10022^T and other Neisseria species are 74.12-85.06 %, lower than the threshold range of 95-96 %. The major cellular fatty acids for our novel species are C16 : 0 and C16:1ω7c/C16:1ω6c, which along with their phenotypic characteristics can distinguish our isolates from other Neisseria species. On the basis of polyphasic analyses, our isolates are proposed to represent a novel species in genus Neisseria, with the name Neisseria weixii sp. nov. The type strain is 10022^T (=DSM 103441^T=CGMCC 1.15732^T).

Citizen science charts two major "stomatotypes" in the oral microbiome of adolescents and reveals links with habits and drinking water composition

BACKGROUND

The oral cavity comprises a rich and diverse microbiome, which plays important roles in health and disease. Previous studies have mostly focused on adult populations or in very young children, whereas the adolescent oral microbiome remains poorly studied. Here, we used a citizen science approach and 16S profiling to assess the oral microbiome of 1500 adolescents around Spain and its relationships with lifestyle, diet, hygiene, and socioeconomic and environmental parameters.

RESULTS

Our results provide a detailed snapshot of the adolescent oral microbiome and how it varies with lifestyle and other factors. In addition to hygiene and dietary habits, we found that the composition of tap water was related to important changes in the abundance of several bacterial genera. This points to an important role of drinking water in shaping the oral microbiota, which has been so far poorly explored. Overall, the microbiome samples of our study can be clustered into two broad compositional patterns (stomatotypes), driven mostly by Neisseria and Prevotella, respectively. These patterns show striking similarities with those found in unrelated populations.

CONCLUSIONS

We hypothesize that these stomatotypes represent two possible global optimal equilibria in the oral microbiome that reflect underlying constraints of the human oral niche. As such, they should be found across a variety of geographical regions, lifestyles, and ages.

Reduced microbiome alpha diversity in young patients with ADHD

ADHD is a psychiatric disorder which is characterized by hyperactivity, impulsivity and attention problems. Due to recent findings of microbial involvement in other psychiatric disorders like autism and depression, a role of the gut microbiota in ADHD pathogenesis is assumed but has not yet been investigated. In this study, the gut microbiota of 14 male ADHD patients (mean age: 11.9 yrs.) and 17 male controls (mean age: 13.1 yrs.) was examined via next generation sequencing of 16S rDNA and analyzed for diversity and biomarkers. We found that the microbial diversity (alpha diversity) was significantly decreased in ADHD patients compared to controls (pShannon = 0.036) and that the composition (beta diversity) differed significantly between patients and controls (pANOSIM = 0.033, pADONIS = 0.006, pbetadisper = 0.002). In detail, the bacterial family Prevotellacae was associated with controls, while patients with ADHD showed elevated levels of Bacteroidaceae, and both Neisseriaceae and Neisseria spec. were found as possible biomarkers for juvenile ADHD. Our results point to a possible link of certain microbiota with ADHD, with Neisseria spec. being a very promising ADHD-associated candidate. This finding provides the basis for a systematic, longitudinal assessment of the role of the gut microbiome in ADHD, yielding promising potential for both prevention and therapeutic intervention.

Isolation and characterization of Neisseria musculi sp. nov., from the wild house mouse

Members of the genus Neisseria have been isolated from or detected in a wide range of animals, from non-human primates and felids to a rodent, the guinea pig. By means of selective culture, biochemical testing, Gram staining and PCR screening for the Neisseria-specific internal transcribed spacer region of the rRNA operon, we isolated four strains of the genus Neisseria from the oral cavity of the wild house mouse, Mus musculus subsp. domesticus. The isolates are highly related and form a separate clade in the genus, as judged by tree analyses using either multi-locus sequence typing of ribosomal genes or core genes. One isolate, provisionally named Neisseria musculi sp. nov. (type strain AP2031T=DSM 101846T=CCUG 68283T=LMG 29261T), was studied further. Strain AP2031T/N. musculi grew well in vitro. It was naturally competent, taking up DNA in a DNA uptake sequence and pilT-dependent manner, and was amenable to genetic manipulation. These and other genomic attributes of N. musculi sp. nov. make it an ideal candidate for use in developing a mouse model for studying Neisseria-host interactions.

Identifying Neisseria species by use of the 50S ribosomal protein L6 (rplF) gene

The comparison of 16S rRNA gene sequences is widely used to differentiate bacteria; however, this gene can lack resolution among closely related but distinct members of the same genus. This is a problem in clinical situations in those genera, such as Neisseria, where some species are associated with disease while others are not. Here, we identified and validated an alternative genetic target common to all Neisseria species which can be readily sequenced to provide an assay that rapidly and accurately discriminates among members of the genus. Ribosomal multilocus sequence typing (rMLST) using ribosomal protein genes has been shown to unambiguously identify these bacteria. The PubMLST Neisseria database (http://pubmlst.org/neisseria/) was queried to extract the 53 ribosomal protein gene sequences from 44 genomes from diverse species. Phylogenies reconstructed from these genes were examined, and a single 413-bp fragment of the 50S ribosomal protein L6 (rplF) gene was identified which produced a phylogeny that was congruent with the phylogeny reconstructed from concatenated ribosomal protein genes. Primers that enabled the amplification and direct sequencing of the rplF gene fragment were designed to validate the assay in vitro and in silico. Allele sequences were defined for the gene fragment, associated with particular species names, and stored on the PubMLST Neisseria database, providing a curated electronic resource. This approach provides an alternative to 16S rRNA gene sequencing, which can be readily replicated for other organisms for which more resolution is required, and it has potential applications in high-resolution metagenomic studies.

The use of high-throughput DNA sequencing in the investigation of antigenic variation: application to Neisseria species

Antigenic variation occurs in a broad range of species. This process resembles gene conversion in that variant DNA is unidirectionally transferred from partial gene copies (or silent loci) into an expression locus. Previous studies of antigenic variation have involved the amplification and sequencing of individual genes from hundreds of colonies. Using the pilE gene from Neisseria gonorrhoeae we have demonstrated that it is possible to use PCR amplification, followed by high-throughput DNA sequencing and a novel assembly process, to detect individual antigenic variation events. The ability to detect these events was much greater than has previously been possible. In N. gonorrhoeae most silent loci contain multiple partial gene copies. Here we show that there is a bias towards using the copy at the 3' end of the silent loci (copy 1) as the donor sequence. The pilE gene of N. gonorrhoeae and some strains of Neisseria meningitidis encode class I pilin, but strains of N. meningitidis from clonal complexes 8 and 11 encode a class II pilin. We have confirmed that the class II pili of meningococcal strain FAM18 (clonal complex 11) are non-variable, and this is also true for the class II pili of strain NMB from clonal complex 8. In addition when a gene encoding class I pilin was moved into the meningococcal strain NMB background there was no evidence of antigenic variation. Finally we investigated several members of the opa gene family of N. gonorrhoeae, where it has been suggested that limited variation occurs. Variation was detected in the opaK gene that is located close to pilE, but not at the opaJ gene located elsewhere on the genome. The approach described here promises to dramatically improve studies of the extent and nature of antigenic variation systems in a variety of species.

Neisseria infection of rhesus macaques as a model to study colonization, transmission, persistence, and horizontal gene transfer

The strict tropism of many pathogens for man hampers the development of animal models that recapitulate important microbe-host interactions. We developed a rhesus macaque model for studying Neisseria-host interactions using Neisseria species indigenous to the animal. We report that Neisseria are common inhabitants of the rhesus macaque. Neisseria isolated from the rhesus macaque recolonize animals after laboratory passage, persist in the animals for at least 72 d, and are transmitted between animals. Neisseria are naturally competent and acquire genetic markers from each other in vivo, in the absence of selection, within 44 d after colonization. Neisseria macacae encodes orthologs of known or presumed virulence factors of human-adapted Neisseria, as well as current or candidate vaccine antigens. We conclude that the rhesus macaque model will allow studies of the molecular mechanisms of Neisseria colonization, transmission, persistence, and horizontal gene transfer. The model can potentially be developed further for preclinical testing of vaccine candidates.

First reported isolation of Neisseria canis from a deep facial wound infection in a dog

Neisseria canis was isolated in pure culture from a mandibular abscess in a dog. Ultrasound-guided fine-needle aspiration was used to obtain a sample from the abscess. Conventional bacteriological examination techniques followed by 16S rRNA gene sequencing from pure subculture and construction of a phylogenetic tree verified the isolate as N. canis. 16S rRNA sequence analysis revealed that a broader phylogenetic platform is needed in the part of the phylogenetic tree where the canine pathogenic N. canis isolate is located. The canine pathogenic isolate was found to be resistant to cephalexin and trimethoprim.

Application of atmospheric pressure matrix-assisted laser desorption/ionization mass spectrometry for rapid identification of Neisseria species

Atmospheric pressure matrix-assisted laser desorption/ionization mass spectrometry (AP-MALDI MS) was applied to develop a proteomics-based method to detect and identify Neisseria species. Heat-inactivated clinical isolate cell suspensions of Neisseria gonorrhoeae and strains belonging to five serogroups (A, B, C, W135, and Y) of Neisseria meningitidis were subjected to on-probe protein/peptide extraction and tryptic digestion followed by AP-MALDI tandem MS (MS/MS)-based proteomic analysis. Amino acid sequences derived from three protonated peptides with m/z values of 1743.8, 1894.8, and 1946.8 were identified by AP-MALDI MS/MS and MASCOT proteome database search analysis as belonging to neisserial acyl carrier protein, neisserial-conserved hypothetical protein, and neisserial putative DNA binding protein, respectively. These three peptide masses can thus be potential biomarkers for neisserial species identification by AP-MALDI MS.

Chloramphenicol is a substrate for a novel nitroreductase pathway in Haemophilus influenzae

The p-nitroaromatic antibiotic chloramphenicol has been used extensively to treat life-threatening infections due to Haemophilus influenzae and Neisseria meningitidis; its mechanism of action is the inhibition of protein synthesis. We found that during incubation with H. influenzae cells and lysates, chloramphenicol is converted to a 4-aminophenyl allylic alcohol that lacks antibacterial activity. The allylic alcohol moiety undergoes facile re-addition of water to restore the 1,3-diol, as well as further dehydration driven by the aromatic amine to form the iminoquinone. Several Neisseria species and most chloramphenicol-susceptible Haemophilus species, but not Escherichia coli or other gram-negative or gram-positive bacteria we examined, were also found to metabolize chloramphenicol. The products of chloramphenicol metabolism by species other than H. influenzae have not yet been characterized. The strains reducing the antibiotic were chloramphenicol susceptible, indicating that the pathway does not appear to mediate chloramphenicol resistance. The role of this novel nitroreductase pathway in the physiology of H. influenzae and Neisseria species is unknown. Further understanding of the H. influenzae chloramphenicol reduction pathway will contribute to our knowledge of the diversity of prokaryotic nitroreductase mechanisms.

Classification of Centers for Disease Control Group Eugonic Fermenter (EF)-4a and EF-4b as Neisseria animaloris sp. nov. and Neisseria zoodegmatis sp. nov., respectively

A polyphasic taxonomic study was performed on isolates classified as Centers for Disease Control Group Eugonic Fermenter (EF)-4a and EF-4b. Comparative 16S rRNA gene sequence analysis confirmed that group EF-4a and EF-4b belong to the genus Neisseria with Neisseria canis and Neisseria dentiae as the nearest phylogenetic neighbours. DNA-DNA hybridizations and biochemical analyses demonstrated that isolates of group EF-4a and EF-4b represent two novel species within this sublineage of the genus Neisseria. Based on the results of the present study, isolates of group EF-4a and EF-4b are classified as Neisseria animaloris sp. nov. (type strain LMG 23011(T)=NCTC 12228(T)) and Neisseria zoodegmatis sp. nov. (type strain LMG 23012(T)=NCTC 12230(T)), respectively.

Neisseria bacilliformis sp. nov. isolated from human infections

Most Neisseria species are gram-negative cocci or diplococci; currently, N. elongata is the only species of human origin with a bacillary morphology. Here, we report isolation and characterization of eight strains of another bacillary Neisseria species from human infections. The organisms caused or contributed to either oral cavity-related or respiratory tract infections, and two strains were isolated from blood cultures. The 16S rRNA gene sequences of these organisms, being homogenous or nearly so (99.4 to 100% identity), matched at <96% known Neisseria species and formed a distinct group within the genus. Analysis of the cellular fatty acids showed broad similarity with a few Neisseria species. The organisms were gram negative and measured 0.6 mum by 1.3 to 3.0 mum. They grew well on chocolate agar and on sheep blood agar but did not grow on modified Thayer-Martin agar. They were positive for oxidase and negative for indole production. There was no acid production from dextrose, lactose, maltose, or sucrose. The tests for catalase reaction, nitrate reduction, and tributilin varied with the strains. These results suggest that these organisms represent a novel species within the genus Neisseria, for which the name Neisseria bacilliformis sp. nov. is proposed. The type strain is MDA2833 = ATCC BAA-1200(T) = CCUG50858(T). Distinction between N. bacilliformis and N. elongata can be made confidently by 16S rRNA gene sequencing or cellular fatty acid profiling but may be difficult by morphology or routine biochemical tests.

New approaches to identification of bacterial pathogens by surface enhanced laser desorption/ionization time of flight mass spectrometry in concert with artificial neural networks, with special reference to Neisseria gonorrhoeae

Surface enhanced laser desorption/ionization-time of flight mass spectrometry (SELDI-TOF MS) has been applied in large numbers of oncological studies but the microbiological field has not been extensively explored to date. This paper describes the application of SELDI-TOF MS in concert with a multi-layer perceptron artificial neural network (ANN) with a back propagation algorithm for the identification of Neisseria gonorrhoeae. N. gonorrhoeae, the aetiological agent of gonorrhoea, is the second most common sexually transmitted disease in the UK and USA. Analysis of over 350 strains of N. gonorrhoeae and closely related species by SELDI-TOF MS facilitated the design of an ANN model and revealed 20 ion peak descriptors of positive, negative and secondary nature that were paramount for the identification of the pathogen. The model performed with over 96 % efficiency when based on these 20 ion peak descriptors and exhibited a sensitivity of 95.7 % and a specificity of 97.1 %, with an area under the curve value of 0.996. The technology has the potential to link several ANN models for a comprehensive rapid identification platform for clinically important pathogens.

Identification of pathogen-specific genes through microarray analysis of pathogenic and commensal Neisseria species

The release of the complete genome sequences of Neisseria meningitidis MC58 and Z2491 along with access to the sequences of N. meningitidis FAM18 and Neisseria gonorrhoeae FA1090 allowed the construction of a pan-Neisseria microarray, with every gene in all four genomes represented. The microarray was used to analyse a selection of strains including all N. meningitidis serogroups and commensal Neisseria species. For each strain, genes were defined as present, divergent or absent using gack analysis software. Comparison of the strains identified genes that were conserved within N. meningitidis serogroup B strains but absent from all commensal strains tested, consisting of mainly virulence-associated genes and transmissible elements. The microarray was able to distinguish between pilin genes, pilC orthologues and serogroup-specific capsule biosynthetic genes, and to identify dam and drg genotypes. Previously described N. meningitidis genes involved in iron response, adherence to epithelial cells, and pathogenicity were compared to the microarray analysis. The microarray data correlated with other genetic typing methods and were able to predict genotypes for uncharacterized strains and thus offer the potential for a rapid typing method. The subset of pathogen-specific genes identified represents potential drug or vaccine targets that would not eliminate commensal neisseriae and the associated naturally acquired immunity.

Neisserial pilin genes display extensive interspecies diversity

All Neisseria live in association with host cells, however, little is known about the genetic potential of nonpathogenic Neisseria species to express attachment factors such as pili. In this study, we demonstrate that type IV pilin-encoding genes are present in a wide range of Neisseria species. N. sicca, N. subflava, and N. elongata each contain two putative pilE genes arranged in tandem, while single genes were identified in N. polysaccharea, N. mucosa, and N. denitrificans. Neisserial pilE genes are highly diverse and display features consistent with a history of horizontal gene transfer.

[The diagnostic specificity of the antigen-binding lymphocyte test in Neisseria-induced infections]

Neisseria-induce different infections, but many representatives of this genus are saprophytes. In this connection it is important to evaluate the species, and for N. meningitidis also group specificity of the immunological diagnostics of meningococcal infection and gonorrhea. In this work the specificity of the antigen-binding lymphocyte test was studied in experiments with the immunization of rabbits and the examination of patients. In the tests of indirect rosette-formation and its inhibition the role of antigenic relationships between different pathogenic and nonpathogenic Neisseria was excluded and the species and group specificity of our Neisseria immunoreagents, used in the diagnostics of meningococcal infection and gonorrhea, was proved.

Molecular cloning and functional characterization of fumarases C in Neisseria species

Fumarase is one of the key enzymes in the TCA cycle and has been implicated in virulence and survival of some microorganisms under suboptimal environmental conditions. In this study, the fumC genes that encode fumarase C (FUMCs) from Neisseria meningitidis, N. gonorrhoeae and N. subflava were identified by homology-based analysis, cloned by polymerase chain reactions and fully sequenced. The inferred primary sequence of neisserial FUMCs showed a high degree of conservation with 97.8-98.7% amino acid identity. However, phylogenetic analysis revealed that these neisserial FUMCs are divergent from class II fumarases found in other microorganisms, rat and human. The putative fumC genes were subcloned into the expression vector, pGEX-6P-1 and efficiently expressed in Esherichia coli BL21. The purified recombinant fusion proteins obtained by affinity chromatography demonstrated high catalytic activities (120-180 U/mg), thus authenticating the identities and functionalities of the cloned genes. Whether FUMC has any physiological relevance to the pathogenesisity of Neisseriae must await future gene disruption or mutagenesis studies.

Endocarditis due to a new rod-shaped Neisseria sp

We report the first case of pacemaker endocarditis due to a new rod-shaped Neisseria sp. isolated from blood culture. On the basis of rrs sequencing, the isolate was found to be most closely related to an uncultured organism from human subgingival plaque and was identified as Neisseria sp. group AK105. A cure was achieved after a combination of surgical and antibiotic treatment. Oral flora-induced pacemaker endocarditis is a rare condition that reinforces the need for good oral hygiene as an important preventive measure.

Fuzzy species among recombinogenic bacteria

Background

It is a matter of ongoing debate whether a universal species concept is possible for bacteria. Indeed, it is not clear whether closely related isolates of bacteria typically form discrete genotypic clusters that can be assigned as species. The most challenging test of whether species can be clearly delineated is provided by analysis of large populations of closely-related, highly recombinogenic, bacteria that colonise the same body site. We have used concatenated sequences of seven house-keeping loci from 770 strains of 11 named Neisseria species, and phylogenetic trees, to investigate whether genotypic clusters can be resolved among these recombinogenic bacteria and, if so, the extent to which they correspond to named species.

Results

Alleles at individual loci were widely distributed among the named species but this distorting effect of recombination was largely buffered by using concatenated sequences, which resolved clusters corresponding to the three species most numerous in the sample, N. meningitidis, N. lactamica and N. gonorrhoeae. A few isolates arose from the branch that separated N. meningitidis from N. lactamica leading us to describe these species as 'fuzzy'.

Conclusion

A multilocus approach using large samples of closely related isolates delineates species even in the highly recombinogenic human Neisseria where individual loci are inadequate for the task. This approach should be applied by taxonomists to large samples of other groups of closely-related bacteria, and especially to those where species delineation has historically been difficult, to determine whether genotypic clusters can be delineated, and to guide the definition of species.

Vaccine potential of the Neisseria meningitidis 2086 lipoprotein

A novel antigen that induces cross-reactive bactericidal antibodies against a number of Neisseria meningitidis strains is described. This antigen, a approximately 28-kDa lipoprotein called LP2086, was first observed within a complex mixture of soluble outer membrane proteins (sOMPs) following a series of fractionation, protein purification, and proteomics steps. Approximately 95 different neisserial isolates tested positive by Western blotting and PCR screening methods for the presence of the protein and the gene encoding LP2086. The strains tested included isolates of N. meningitidis serogroups A, B, C, W135, and Y, Neisseria gonorrhoeae, and Neisseria lactamica. To better understand the microheterogeneity of this protein, the 2086 genes from 63 neisserial isolates were sequenced. Two different subfamilies of LP2086 were identified based on deduced amino acid sequence homology. A high degree of amino acid sequence similarity exists within each 2086 subfamily. The highest degree of genetic diversity was seen between the two subfamilies which share approximately 60 to 75% homology at the nucleic acid level. Flow cytometry (fluorescence-activated cell sorting) analyses and electron microscopy indicated that the LP2086 is localized on the outer surface of N. meningitidis. Antiserum produced against a single protein variant was capable of eliciting bactericidal activity against strains expressing different serosubtype antigens. Combining one recombinant lipidated 2086 (rLP2086) variant from each subfamily with two rPorA variants elicited bactericidal activity against all strains tested. The rLP2086 family of antigens are candidates worthy of further vaccine development.

[Studies on the infection status of seven species Mycoplasma, three species of Chlamydia, Neisseria gonorrhoeae and Garderella vaginalis in 76 patients with sexual transmitted diseases]

OBJECTIVE

To study the infectious status of seven species of Mycoplasma, three species of Chlamydia, Neisseria gonorrhoeae and Garderella vaginalis in the 76 male sexual transmitted disease (STD) patients in Yangzhou city.

METHODS

Twelve species of pathogens including Ureaplasma urealyticum (Uu), Mycoplasma hominis (Mh), Mycoplasma pneumoniae (Mpn), Mycoplasma genitalium (Mg), Mycoplasma fermentans (Mf), Mycoplasma penetrans (Mpe), Mycoplasma prium (Mpi), Chlamydia trachomatis (Ct), Chlamydia pneumoniae (Cpn), Chlamydia psittaci (Cps), Neisseria gonorrhoeae (Ng) and Garderella vaginalis (GV) were detected by nested polymerase chain reaction including PPNG.

RESULTS

The positive rates of Uu, Mh, Mpn, Mg, Mf, Mpe, Ct, Ng were 64.5%, 27.6%, 26.3%, 18.4%, 2.6%, 2.6%, 31.6%, 36.8%, in which Penicillinase-producing neisseria gonorrhoeae (PPNG) accounted for 14.3%, GV 15.8%. No Mpi, Cpn or Cps were found. There was more significant therapeutic effects on the detectable rate of Mycoplasma nucleic acid between positive gonococcus and negative gonococcus in male STDs patients (chi(2) = 3.848, P < 0.05).

CONCLUSION

The infection rates of Mycoplasma, Chlamydia, Ng and GV were high among male STD patients in Yangzhou city. In clinical practice, more attention should be paid on correct diagnosis and treatment for patients, with Gonococcus, Chlamydia, Mycoplasma and GV.

Application of denaturing gradient gel electrophoresis (DGGE) to the analysis of microbial communities of subgingival plaque

OBJECTIVES

Denaturing gradient gel electrophoresis (DGGE) was applied to the microbiologic examination of subgingival plaque.

MATERIALS AND METHODS

The PCR primers were designed from conserved nucleotide sequences on 16S ribosomal RNA gene (16SrDNA) with GC rich clamp at the 5'-end. Polymerase chain reaction (PCR) was performed using the primers and genomic DNAs of typical periodontal bacteria. The generated 16SrDNA fragments were separated by denaturing gel.

RESULTS

Although the sizes of the amplified DNA fragments were almost the same among the species, 16SrDNAs of the periodontal bacteria were distinguished according to their specific sequences. The microflora of clinical plaque samples were profiled by the PCR-DGGE method, and the dominant 16SrDNA bands were cloned and sequenced. Simultaneously, Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis and Prevotella intermedia were detected by an ordinary PCR method. In the deep periodontal pockets, the bacterial community structures were complicated and P. gingivalis was the most dominant species, whereas the DGGE profiles were simple and Streptococcus or Neisseria species were dominant in the shallow pockets. The species-specific PCR method revealed the presence of A. actinomycetemcomitans, P. gingivalis and P. intermedia in the clinical samples. However, corresponding bands were not always observed in the DGGE profiles, indicating a lower sensitivity of the DGGE method.

CONCLUSION

Although the DGGE method may have a lower sensitivity than the ordinary PCR methods, it could visualize the bacterial qualitative compositions and reveal the major species of the plaque. The DGGE analysis and following sequencing may have the potential to be a promising bacterial examination procedure in periodontal diseases.

Aortic prosthetic endocarditis with Neisseria elongata subspecies nitroreducens

A case of Neisseria elongata subsp. nitroreducens endocarditis with a favourable course is presented. Dental foci were involved as the infective origin. Only conservative therapy was performed for 6 weeks; no complications were registered in 3 months of follow-up. The other 12 cases with similar aetiology communicated in the past 30 y were reviewed.

Utilization of 16S ribosomal DNA sequencing for diagnosis of septicemia due to Neisseria elongata subsp. glycolytica in a neutropenic patient

Septicemia due to Neisseria elongata subsp. glycolytica occurs infrequently. We report a case of septicemia in a patient undergoing antimitotic chemotherapy. Gram-negative coccobacilli were isolated from blood cultures. The identity of the isolate by phenotypic methods was uncertain. In contrast, identity was confirmed by 16S ribosomal DNA sequencing, which appeared to be very useful for correct identification.

Evaluation of the BactiCard Neisseria for identification of pathogenic Neisseria species and Moraxella catarrhalis

The BactiCard Neisseria (Remel, USA) is a chromogenic enzyme substrate system for identifying Neisseria gonorrhoeae, Neisseria meningitidis, Neisseria lactamica, and Moraxella catarrhalis. The identification system consists of a card with four test circles impregnated with chromogenic substrates for indoxyl butyrate esterase (IB), prolyl aminopeptidase (PRO), gamma-glutamyl aminopeptidase (GLUT), and ss-galactosidase (BGAL). These substrates permit the identification of Moraxella catarrhalis, Neisseria gonorrhoeae, Neisseria meningitidis, and Neisseria lactamica, respectively. After hydration of the circles with buffer, colonies from growth on selective media or a subculture are applied to the four circles. IB and BGAL reactions are read for a blue-green color after 2 and 15 min, respectively. PRO and GLUT reactions are read at 15 min for a red color after addition of a developer reagent. Identifications obtained with the BactiCard Neisseria were compared with those obtained using conventional procedures for 558 isolates in a blinded fashion. The BactiCard Neisseria identified 100% of 254 Neisseria gonorrhoeae, 100% of 125 Neisseria meningitidis, 53 (98.2%) of 54 Neisseria lactamica, and 123 (98.4%) of 125 Moraxella catarrhalis isolates. The BactiCard Neisseria is an accurate and rapid system for identification of these microorganisms in the clinical laboratory.

Cell adhesion receptors - signaling capacity and exploitation by bacterial pathogens

Cell adhesion receptors play an essential role in multicellular organisms by mediating the direct association of cells with each other and with proteins of the extracellular matrix. Members of different protein families such as integrins, cadherins, immunoglobulin superfamily cell adhesion molecules (IgCAMs), selectins, and syndecans not only support the structural integrity of cells and tissues, but also contribute to the transduction of signals. Interestingly, several of these molecules are exploited by bacterial pathogens to establish tight contact with eukaryotic cells. Using the example of integrins, cadherins, and IgCAMs, this review illustrates the signaling capacity of cell adhesion receptors and highlights a number of bacterial adhesins that are known to engage these receptors. Where applicable, the role of the receptor-adhesin interaction in the course of the infection is discussed.

Actinobacillus actinomycetemcomitans in a rural adult population in southern Thailand

The prevalence of Actinobacillus actinomycetemcomitans isolates was examined in a rural population of southern Thailand. Sixty individuals aged 30-39 and 50-59 years were randomly selected from a group of 363 persons, living in four villages, who had been clinically examined previously. A subgingival plaque sample was taken with a curette from the mesial aspect of the two upper and lower first molars. Each sample was dispersed in 3.3 ml of VMGA III transport medium and spread onto Trypticase Soy Broth with Bacitracin and Vancomycin (TSBV)-agar plates on the same day. After incubation in 10% CO2 for 5 days the plates were examined for typical A. actinomycetemcomitans colonies which were tested for catalase activity. Each strain was further tested for biochemical characteristics, serotyped against serotype-specific antisera a-e and ribotyped after DNA digestion using the restriction endonucleases HindIII and EcoRI. For 53 (88%) of the 60 individuals, A. actinomycetemcomitans was present in at least one subgingival sample, which is considerably higher than the prevalence in Western European adults. In 11 individuals, two or three different strains were found. Serotypes a and c were the most prevalent, and serotype b was found only once among 46 tested isolates. Eleven ribotypes were found among the 46 strains. While the same ribotype could be found among individuals of the same village, no ribotype of A. actinomycetemcomitans was unique for individuals of any one village. The study demonstrated a high prevalence of A. actinomycetemcomitans among adults of the rural population of southern Thailand and indicates that this species is present as part of the resident oral flora in this population.

Prevalence and risk indicators for destructive periodontal diseases in 3 urban American minority populations

BACKGROUND, AIMS

Destructive periodontal diseases have been reported disproportionately more prevalent and severe in African-Americans relative to other American populations. Differences in subgingival microbiota and host immune response have also been reported for African-Americans, implying that risk factors for disease progression may also differ for these populations. Since it is not clear whether these differences are truly genetic or due to confounding variables such as social economic status, we examined a series of clinical, environmental, demographic, and microbiologic features associated with periodontal disease status in a group of 185 urban minority subjects resident within the greater New York metropolitan area.

METHODS

The study population consisted of 56 Asian-American, 71 African-American and 58 Hispanic subjects. Clinical data recorded included pocket depth, attachment level, gingival erythema, bleeding upon probing, suppuration, and the presence of supragingival plaque. Environmental and demographic data recorded included smoking history, years resident in the United States, whether the subject reported a private dentist and occupational status. Subgingival plaque was sampled from the mesial aspect of all teeth exclusive of third molars and the levels of 40 subgingival species enumerated using checkerboard DNA-DNA hybridization.

RESULTS

The African-American group had more missing teeth, deeper periodontal pocket depth and more attachment loss than the Asian-American or Hispanic groups. However, the African-American group were less likely to report having a private dentist, had a greater proportion of smokers and a greater proportion of unskilled individuals. The profile of subgingival species differed among the three ethnic/racial groups with A. actinomycetemcomitans, N. mucosa, S. noxia and T. socranskii significantly elevated in the Asian-American group and P. micros significantly elevated in the African-American group. When subset by occupational status, numbers of missing teeth, pocket depth, attachment level and prior disease activity were all found increased in the unskilled relative to the professional group. Local factors including the mean % of sites with plaque, marginal gingival erythema, bleeding upon probing and suppuration were also elevated in the unskilled group. The microbial profile differed among the 3 occupational groups with the unskilled group having elevated numbers of species associated with destructive periodontal diseases.

CONCLUSIONS

Although greater destructive periodontal disease prevalence and severity were found in the African-American group, these results suggest that environmental and demographic variables, such as occupational status, may have a greater influence on risk indicators associated with disease prevalence and progression in these populations.

Comparative whole-genome analyses reveal over 100 putative phase-variable genes in the pathogenic Neisseria spp

Previously, a complete genome analysis of Neisseria meningitidis strain MC58 revealed the largest repertoire of putative phase-variable genes described in any species to date. Initial comparisons with two incomplete Neisseria spp. genome sequences available at that time revealed differences in the repeats associated with these genes in the form of polymorphisms, the absence of the potentially unstable elements in some alleles, and in the repertoire of the genes that were present. Analyses of the complete genomes of N. meningitidis strain Z2491 and Neisseria gonorrhoeae strain FA1090 have been performed and are combined with a comprehensive comparative analysis between the three available complete genome sequences. This has increased the sensitivity of these searches and provided additional contextual information that facilitates the interpretation of the functional consequences of repeat instability. This analysis identified: (i) 68 phase-variable gene candidates in N. meningitidis strain Z2491, rather than the 27 previously reported; (ii) 83 candidates in N. gonorrhoeae strain FA1090; and (iii) 82 candidates in N. meningitidis strain MC58, including an additional 19 identified through cross-comparisons with the other two strains. In addition to the 18 members of the opa gene family, a repertoire of 119 putative phase-variable genes is described, indicating a huge potential for diversification mediated by this mechanism of gene switching in these species that is central to their interactions with the host and environmental transitions. Eighty-two of these are either known (14) or strong (68) candidates for phase variation, which together with the opa genes make a total of 100 identified genes. The repertoires of the genes identified in this analysis diverge from the different species groupings, indicating horizontal exchange that significantly affects the species and strain complements of these genes.

The changing face of odontogenic infections

PURPOSE

The purpose of this investigation was to compare characteristics of patients hospitalized with odontogenic infections during the 1980s to those of the 1990s.

PATIENTS AND METHODS

This study was a retrospective record review that compared 2 cohorts of patients admitted to the same institution during two 81-month periods, one decade apart. Admission criteria were face or neck swelling suggesting abscess or cellulitis and one or more of the following: temperature above 38 degrees C, white blood cell (WBC) count greater than 10.8 x 10(3)/microL, or concern about airway compromise. Characteristics reviewed were age, gender, race, admission temperature, admission WBC count, fascial space(s) involved, tooth of etiology, duration of hospitalization, and bacteria isolated. Data were compared for statistical significance (P <.05).

RESULTS

No significant differences were found between the 2 cohorts for age, gender, race, admission temperature, admission WBC count, space involvement, or length of stay (P <.05). One tooth (mandibular left first molar) of 52 was involved more frequently in the 1990 group (P <.03). Gram-positive cocci were isolated significantly more frequently from the 1990s patients than from the 1980s patients (P <.03). There were also significant differences (P <.02) between cohorts in the isolation frequency of individual genera, such as alpha-hemolytic Streptococci, coagulase negative staphylococci, Staphylococcus epidermidis, Bacteroides melanogenicus, beta-lactamase positive Bacteroides, Eikenella corrodens, and Neisseria species. Eighty-one percent of the bacteria cultured from the 1990s patients were resistant to one or more common antibiotics; 47% of these organisms were Staphylococcus aureus.

CONCLUSION

No clinically significant differences existed in the characteristics of patients hospitalized with odontogenic infections between the 1980s and the 1990s. Although there were differences in the type and prevalence of bacteria isolated, this was probably a result of changes in nomenclature, identification protocols, and isolation techniques.

Genetic diversity of Neisseria lactamica strains from epidemiologically defined carriers

We assessed the genetic diversity of 26 Neisseria lactamica strains from epidemiologically related sources, i.e., groups of kindergartens and primary schools in three Bavarian towns, by the partial sequencing of the argF, rho, recA, and 16S ribosomal genes. We found a total of 17 genotypes, of which 12 were found only in one strain. The genotypes comprised 5 alleles of the argF gene, 9 of rho, 8 of recA, and 10 of the 16S ribosomal DNA. Sequence analysis by determination of homoplasy ratios and split decomposition analysis revealed abundant recombination within N. lactamica.

Oral colonization of aerobic and facultatively anaerobic gram-negative rods and cocci in irradiated, dentate, xerostomic individuals

This study aimed at investigating the oral colonization of aerobic and facultatively anaerobic gram-negative rods and cocci in head- and neck-irradiated, dentate, xerostomic individuals. Subjects were recruited from a nasopharyngeal carcinoma clinic and were segregated into group A: <60 years (n=25, 48+/-6 years, 5+/-5 years post-irradiation) and group B: >or=60 years (n=8, 67+/-4 years, 2+/-2 years post-irradiation) and were compared with age- and sex-matched normal individuals, group C: <60 years (n=20, 44+/-12 years) and group D: >or=60 years (n=10, 70+/-3 years). Selective culture of the oral rinse samples was carried out to isolate, quantify and speciate (using API 20E kit) aerobic and facultatively anaerobic gram-negative rods and cocci recovery. All test subjects were put under comprehensive oral and preventive care for 3 months, and 12 group A and 5 group B subjects were recalled for reassessment of aerobic and facultatively anaerobic gram-negative rods and cocci colonization. All identical isolates, pre- and post-hygienic care, were phenotypically (Vitek, Hazelwood, MA and antibiogram profile) and genotypically (pulsed-field gel electrophoresis) evaluated. The aerobic and facultatively anaerobic gram-negative rods and cocci isolated from the first round oral rinse samples included: Acinetobacter, Neisseria, Chryseomonas, Flavimonas, Pseudomonas, Citrobacter, Enterobacter, Escherichia, Klebsiella, Flavobacterium and Weeksella species. The aerobic and facultatively anaerobic gram-negative rods and cocci isolation rate was high for irradiated individuals, and they were 64/25% and 100/80% for groups A/C and B/D, respectively. Recovery of aerobic and facultatively anaerobic gram-negative rods and cocci and Klebsiella pneumoniae subsp. pneumoniae in oral rinse samples were found to be significantly more prevalent in the irradiated subjects (groups A and B). Enterobacteriaceae were more frequently isolated from oral rinse samples of aged irradiated subjects (group B vs D, P<0.05), where the quantity of Citrobacter freundii (colony-forming units/ml oral rinse) was also significantly elevated. The isolation rate of aerobic and facultatively anaerobic gram-negative rods and cocci after hygienic care remained unchanged; 3 of 12 and 3 of 5 of the recalled subjects from groups A and B, respectively, harbored same aerobic and facultatively anaerobic gram-negative rods and cocci species. However, only two pairs of K. pneumoniae subsp. pneumoniae, sequentially isolated from same patients in group B, were found to be identical by pulsed-field gel electrophoresis. This may be due to reinfection of the microbes from the same source or permanent colonization. In conclusion, irradiation-induced xerostomia seems to favor frequent, repeated, transient intraoral colonization of aerobic and facultatively anaerobic gram-negative rods and cocci.

Use of the neisserial lipoprotein (Lip) for subtyping Neisseria gonorrhoeae

The pathogenic Neisseria species N. meningitidis and N. gonorrhoeae possess an outer membrane lipoprotein, designated Lip, which is present in all strains tested. The predicted protein sequence of Lip consists of a consensus AAEAP amino acid repeat. The objective of this study was to determine the feasibility of using the Lip repeat number and sequence for subtyping of Neisseria gonorrhoeae. The lip genes of each isolate were amplified by PCR and sequenced to determine the repeat number and sequence. Among the 46 strains we examined, eight different Lip repeat numbers were identified, with lengths of 11 (1 strain), 12 (14 strains), 13 (2 strains), 14 (10 strains), 15 (5 strains), 16 (10 strains), 17 (3 strains), and 20 (1 strain) repeats. Analysis indicated differences in the sequences within the repeats that resulted in amino acid alterations in repeat classes that contained multiple strains. Among the 46 isolates examined, we were able to identify 17 unique Lip subtyping patterns.

Carriage of N. lactamica in a population at high risk of meningococcal disease

Carriage of Neisseria lactamica among household contacts of meningococcal disease (MCD) cases was investigated during an epidemic in Auckland, New Zealand. The overall carriage rate for N. lactamica was 10.5% (95% CI 7.4-13.5%) with a peak carriage rate in 2-year-olds of 61.5% (95% CI 26.6-88.1%). Factors associated with a significant (P < 0.05) increase in the likelihood of carriage included runny nose, the number of people per bedroom and youth. Genetic analysis of isolates revealed a striking correlation of strains within the same household but a high level of diversity between households, suggesting that household contact is an important factor in acquisition. For household contacts aged less than 5 years, there was a higher rate of carriage amongst those in contact with MCD cases under 8 years old than for contacts of cases aged 8 years and over. It is likely that development of MCD is a reflection of the nature and intensity of the exposure to a virulent strain of N. meningitidis, coupled with an absence of host resistance among those individuals not carrying N. lactamica.

A comparative analysis of pilin genes from pathogenic and nonpathogenic Neisseria species

Pathogenic Neisseria species elaborate type IV pili, which are considered important for virulence. In this study, we examined pilin-encoding expression loci (pilE) in nonpathogenic Neisseria species. PCR based screening detected homology to a conserved N-terminal region of pilE in 12 of 15 Neisseria species, including all human commensal isolates. The three species failing to display homology were isolated from nonhuman sources. We have also characterized complete pilE loci from the human commensal species N. lactamica and N. cinerea. As anticipated, the predicted protein sequences from these species display features typical of all type IV pilins. In addition, these commensal pilins possess two highly conserved regions, SV2 and CYS2, which are shared among all neisserial pilins. However, a comparative analysis of pilE loci from pathogenic and nonpathogenic Neisseria species reveals two distinct structural groups, one composed of the pilin genes from N. lactamica, N. cinerea, and the class II pilin-producing subset of N. meningitidis isolates, the other of gonococcal and meningococcal class I pilin-encoding genes. Since both class I and class II pilin-producing meningococci can act as pathogens, structural relationships among neisserial pilin genes do not obviously reflect either species membership or ability to cause human disease.

Intensity of bacteraemia associated with conservative dental procedures in children

OBJECTIVES

To explore the individual dento-gingival manipulative procedures that together lead to the placement of a restoration and to estimate the associated intensity of bacteraemia.

PATIENTS AND METHODS

Healthy children receiving dental treatment under general anaesthesia provided blood samples 30 seconds after one of four dento-gingival manipulative procedures: 1. Placement of rubber dam, 2. Use of the high speed drill, 3. Use of the slow speed drill, and 4. Placement of matrix band and wedge. Blood cultures were processed to give the percentage prevalence of bacteraemia, the intensity of organisms per millilitre of blood and the identity of the organisms cultured.

RESULTS

A total of 257 children were recruited to the study. The percentage positive prevalence of blood cultures was baseline--9.3%, rubber dam placement--31.4%, slow drill--12.2%, fast drill--4.3%, and matrix band and wedge--32.1%. The intensity of bacteraemia was baseline--1.2 cfu, rubber dam placement--1,962 cfu, slow drill--0.3 cfu, fast drill--1.9 cfu, matrix band and wedge--4.8 cfu.

CONCLUSIONS

These data indicate that dento-gingival manipulative procedures comprising a simple dental restoration can lead to a bacteraemia comparable to that from dental extractions. It is suggested that these data may indicate the need for antibiotic prophylaxis for some aspects of conservative dentistry.

Networks and groups within the genus Neisseria: analysis of argF, recA, rho, and 16S rRNA sequences from human Neisseria species

To understand the pattern of nucleotide sequence variation among bacteria that frequently exchange chromosomal genes, we analyzed sequences of the recA, argF, and rho genes, as well as part of the small-subunit (16S) rRNA gene, from about 50 isolates of human commensal Neisseria species and the pathogenic N. meningitidis and N. gonorrhoeae. Almost all isolates of these species could be assigned to five phylogenetic groups that are found for all genes examined and generally are supported by high bootstrap values. In contrast, the phylogenetic relationships among groups varied according to the gene analyzed with notable incongruences involving N. cinerea and N. lactamica. Further analysis using split decomposition showed that for each gene, including 16S rRNA, the patterns of sequence divergence within N. meningitidis and closely related species were inconsistent with a bifurcating treelike phylogeny and better represented by an interconnected network. These data indicate that the human commensal Neisseria species can be separated into discrete groups of related species but that the relationships both within and among these groups, including those reconstructed using 16S rRNA, have been distorted by interspecies recombination events.

Evaluation of AMPLICOR Neisseria gonorrhoeae PCR using cppB nested PCR and 16S rRNA PCR

Certain strains of Neisseria subflava and Neisseria cinerea are known to produce false-positive results with the AMPLICOR Neisseria gonorrhoeae PCR (Roche Diagnostic Systems, Branchburg, N.J.). The analytical sensitivity and analytical specificity of three PCR tests were assessed with 3 geographically diverse N. gonorrhoeae strains and 30 non-N. gonorrhoeae Neisseria spp. The sensitivities of the in-house nested cppB gene and the 16S rRNA PCR methods were greater than that of the AMPLICOR N. gonorrhoeae PCR with purified DNA from all 3 N. gonorrhoeae strains. Six of 14 clinical strains of N. subflava (1 from a vaginal swab, 5 from respiratory sites) produced false-positive AMPLICOR N. gonorrhoeae PCR results and were negative by the two other PCR methods. When applied to 207 clinical specimens selected from a population with a high prevalence ( approximately 9%) of infection, the results for 15 of 96 (15.6%) AMPLICOR-positive specimens and 14 of 17 (82.3%) AMPLICOR-equivocal specimens were not confirmed by the more sensitive nested cppB PCR method. Only 2 of 94 (2.1%) of AMPLICOR N. gonorrhoeae PCR-negative specimens from the same population tested positive by the nested cppB method. These results suggest that for this population the AMPLICOR N. gonorrhoeae PCR test is suitable as a screening test only and all positive results should be confirmed by a PCR method that is more specific and at least as sensitive. This study also illustrates that caution should be used when introducing commercially available nucleic acid amplification-based diagnostic tests into the regimens of tests used for populations not previously tested with these products.

Carriage of Neisseria meningitidis and Neisseria lactamica among ethnic Greek school children from Russian immigrant families in Athens

During February and March 1995, a survey of meningococcal carriage in 625 school children was carried out in a suburb of Athens in which there was a large number of ethnic Greeks who had immigrated from Russia beginning in the early 1990s. The objectives of the study were: (1) to determine if factors associated with carriage of meningococci observed in a previous study of Greek school children were similar for the immigrant population; (2) to compare phenotypic characteristics of meningococci from the immigrant population with those isolated from children in Athens. Overall isolation rate for meningococci was 82/625 (13.1%), significantly higher than that found for school children in Athens (5.8%) during the winter of 1990 1991 (5.8%) (chi=25.98, P=0.0000003). By univariate analysis, carriage was not associated with sex, number of individuals per household, blood group, secretor status, socioeconomic level or maternal smoking; however, it was associated with fathers' smoking. The high proportion of men who smoked compared with the low proportion of women smokers might contribute to this finding. The main serogroup of meningococci isolated from this population was A (28%). While serogroup A appears to be more prevalent among Russian and Kurdish immigrants (14%) than among Greek school children or military recruits (4%), there has not been an increase in group A meningococcal disease in Greece. The isolation rate for N. lactamica was high 105/625 (17.3%). A few of these strains bound some of the monoclonal antibodies used for meningococcal serotyping and subtyping, and they are being examined in greater detail.

Septicaemia with Neisseria elongata ssp. nitroreducens in a patient with hypertrophic obstructive cardiomyopathia

Neisseria elongata ssp. nitroreducens, a commensal of the human upper respiratory tract, is a newly recognized cause of endocarditis. We report the isolation of the organism from blood cultures of a 30-y-old man with hypertrophic obstructive cardiomyopathy. The patient was successfully treated with benzylpenicillin and netilmicin in combination, followed by ceftriaxone and amoxicillin.

Association of Neisseria cinerea with ocular infections in paediatric patients

Twenty-two strains of Neisseria cinerea were recovered from paediatric patients over a 7-year period and forwarded to the Microbial Diseases Laboratory for biochemical identification and/or confirmation. Eighteen of these 22 strains (82%) were recovered from the eyes of very young children (< or = 1 year), > 50% occurring during the neonatal period. The majority of eye isolates were involved in a variety of ocular infections including orbital cellulitis, conjunctivitis, and eye discharge (most common); in four of the 13 instances (31%) where laboratory data was available, Neisseria cinerea was recovered in pure culture. Neisseria cinerea isolates were often submitted to the Microbial Diseases Laboratory as possible 'N. gonorrhoeae' or 'Neisseria species' due to problems resulting from the use of commercial assays or unfamiliarity with the organism. These observations indicate that N. cinerea can produce eye infections in very young children, who presumably acquire this organism vertically from the mother during birth. Accurate identification of N. cinerea in such infants can preclude the social trauma and possible legal ramifications which can initially result from its misidentification as N. gonorrhoeae.

Traversal of a polarized epithelium by pathogenic Neisseriae: facilitation by type IV pili and maintenance of epithelial barrier function

BACKGROUND

Gonococci (GC) and meningococci (MC) are gram-negative bacterial pathogens that infect human mucosal epithelia. We would like to understand the functions of specific bacterial components at each stage of mucosal colonization: adhesion, cell invasion, and traversal into subepithelial tissues. As no animal model of mucosal colonization by GC or MC is available, increasingly sophisticated in vitro approaches have been used to address these issues.

MATERIALS AND METHODS

We adapted the polarized T84 human epithelial cell system to study GC and MC colonization. Epithelial barrier function was monitored by permeability to soluble tracers and with electrical resistance measurements. Polarized cells were used to assay bacterial traversal of the monolayers, and cells grown on plastic were used to assay adhesion and cell invasion.

RESULTS

All pathogenic Neisseriae examined traversed the monolayers. The traversal times were species specific and identical to times established previously in organ culture studies. In contrast to experiments with some enteric pathogens, transmigration by GC and MC was not accompanied by disruption of the epithelial barrier. GC mutants lacking type IV pili were compromised in adhesion, invasion, and traversal of T84 cells.

CONCLUSIONS

Experiments with polarized T84 cells mimic key features of organ culture infections and reveal additional aspects of neisserial infection. Epithelial barrier function can be retained during bacterial traversal. Experiments with a nonpiliated GC mutant and its wild-type parent indicated an unexpected role for pili in cell invasion. Our results are consistent with the hypothesis that bacterial adhesion, invasion, or both are rate-limiting for traversal across the epithelium.