Structural basis of Cas3 activation in type I-C CRISPR-Cas system.

CRISPR-Cas systems function as adaptive immune mechanisms in bacteria and archaea and offer protection against phages and other mobile genetic elements. Among many types of CRISPR-Cas systems, Type I CRISPR-Cas systems are most abundant, with target interference depending on a multi-subunit, RNA-guided complex known as Cascade that recruits a transacting helicase nuclease, Cas3, to degrade the target. While structural studies on several other types of Cas3 have been conducted long ago, it was only recently that the structural study of Type I-C Cas3 in complex with Cascade was revealed, shedding light on how Cas3 achieve its activity in the Cascade complex. In the present study, we elucidated the first structure of standalone Type I-C Cas3 from Neisseria lactamica (NlaCas3). Structural analysis revealed that the histidine-aspartate (HD) nuclease active site of NlaCas3 was bound to two Fe2+ ions that inhibited its activity. Moreover, NlaCas3 could cleave both single-stranded and double-stranded DNA in the presence of Ni2+ or Co2+, showing the highest activity in the presence of both Ni2+ and Mg2+ ions. By comparing the structural studies of various Cas3 proteins, we determined that our NlaCas3 stays in an inactive conformation, allowing us to understand the structural changes associated with its activation and their implication.

Unveiling the immune dynamics of Neisseria persistent oral colonization.

Commensal bacteria are crucial in maintaining host physiological homeostasis, immune system development, and protection against pathogens. Despite their significance, the factors influencing persistent bacterial colonization and their impact on the host still need to be fully understood. Animal models have served as valuable tools to investigate these interactions, but most have limitations. The bacterial genus Neisseria, which includes both commensal and pathogenic species, has been studied from a pathogenicity to humans perspective but lacks models that study immune responses in the context of long-term persistence. Neisseria musculi, a recently described natural commensal of mice, offers a unique opportunity to study long-term host-commensal interactions. In this study, for the first time, we have used this model to study the transcriptional, phenotypic, and functional dynamics of immune cell signatures in the mucosal and systemic tissue of mice in response to N. musculi colonization. We found key genes and pathways vital for immune homeostasis in palate tissue, validated by flow cytometry of immune cells from the lung, blood, and spleen. This study offers a novel avenue for advancing our understanding of host-bacteria dynamics and may provide a platform for developing efficacious interventions against mucosal persistence by pathogenic Neisseria.

Peptidoglycan fragment release and NOD activation by commensal Neisseria species from humans and other animals.

Neisseria gonorrhoeae, a human restricted pathogen, releases inflammatory peptidoglycan (PG) fragments that contribute to the pathophysiology of pelvic inflammatory disease. The genus Neisseria is also home to multiple species of human- or animal-associated Neisseria that form part of the normal microbiota. Here we characterized PG release from the human-associated nonpathogenic species Neisseria lactamica and Neisseria mucosa and animal-associated Neisseria from macaques and wild mice. An N. mucosa strain and an N. lactamica strain were found to release limited amounts of the proinflammatory monomeric PG fragments. However, a single amino acid difference in the PG fragment permease AmpG resulted in increased PG fragment release in a second N. lactamica strain examined. Neisseria isolated from macaques also showed substantial release of PG monomers. The mouse colonizer Neisseria musculi exhibited PG fragment release similar to that seen in N. gonorrhoeae with PG monomers being the predominant fragments released. All the human-associated species were able to stimulate NOD1 and NOD2 responses. N. musculi was a poor inducer of mouse NOD1, but ldcA mutation increased this response. The ability to genetically manipulate N. musculi and examine effects of different PG fragments or differing amounts of PG fragments during mouse colonization will lead to a better understanding of the roles of PG in Neisseria infections. Overall, we found that only some nonpathogenic Neisseria have diminished release of proinflammatory PG fragments, and there are differences even within a species as to types and amounts of PG fragments released.

A novel murine model mimicking male genital Neisseria species infection using Neisseria musculi†.

With ~78 million cases yearly, the sexually transmitted bacterium Neisseria gonorrhoeae is an urgent threat to global public health due to continued emergence of antimicrobial resistance. In the male reproductive tract, untreated infections may cause permanent damage, poor sperm quality, and subsequently subfertility. Currently, few animal models exist for N. gonorrhoeae infection, which has strict human tropism, and available models have limited translatability to human disease. The absence of appropriate models inhibits the development of vital new diagnostics and treatments. However, the discovery of Neisseria musculi, a mouse oral cavity bacterium, offers much promise. This bacterium has already been used to develop an oral Neisseria infection model, but the feasibility of establishing urogenital gonococcal models is unexplored. We inoculated mice via the intrapenile route with N. musculi. We assessed bacterial burden throughout the male reproductive tract, the systemic and tissue-specific immune response 2-weeks postinfection, and the effect of infection on sperm health. Neisseria musculi was found in penis (2/5) and vas deferens (3/5) tissues. Infection altered immune cell counts: CD19+ (spleen, lymph node, penis), F4/80+ (spleen, lymph node, epididymus), and Gr1+ (penis) compared with noninfected mice. This culminated in sperm from infected mice having poor viability, motility, and morphology. We hypothesize that in the absence of testis infection, infection and inflammation in other reproductive is sufficient to damage sperm quality. Many results herein are consistent with outcomes of gonorrhoea infection, indicating the potential of this model as a tool for enhancing the understanding of Neisseria infections of the human male reproductive tract.

Neisseria genes required for persistence identified via in vivo screening of a transposon mutant library.

The mechanisms used by human adapted commensal Neisseria to shape and maintain a niche in their host are poorly defined. These organisms are common members of the mucosal microbiota and share many putative host interaction factors with Neisseria meningitidis and Neisseria gonorrhoeae. Evaluating the role of these shared factors during host carriage may provide insight into bacterial mechanisms driving both commensalism and asymptomatic infection across the genus. We identified host interaction factors required for niche development and maintenance through in vivo screening of a transposon mutant library of Neisseria musculi, a commensal of wild-caught mice which persistently and asymptomatically colonizes the oral cavity and gut of CAST/EiJ and A/J mice. Approximately 500 candidate genes involved in long-term host interaction were identified. These included homologs of putative N. meningitidis and N. gonorrhoeae virulence factors which have been shown to modulate host interactions in vitro. Importantly, many candidate genes have no assigned function, illustrating how much remains to be learned about Neisseria persistence. Many genes of unknown function are conserved in human adapted Neisseria species; they are likely to provide a gateway for understanding the mechanisms allowing pathogenic and commensal Neisseria to establish and maintain a niche in their natural hosts. Validation of a subset of candidate genes confirmed a role for a polysaccharide capsule in N. musculi persistence but not colonization. Our findings highlight the potential utility of the Neisseria musculi-mouse model as a tool for studying the pathogenic Neisseria; our work represents a first step towards the identification of novel host interaction factors conserved across the genus.

Neisseria leonii sp. nov., isolated from the nose, lung, and liver of rabbits.

A taxogenomic study of three strains (3986T, 51.81, and JF 2415) isolated from rabbits between 1972 and 2000 led to the description of a new Neisseria species. The highest sequence similarity of the 16S rRNA gene was found to Neisseria animalis NCTC 10212T (96.7 %). The 16S rRNA gene similarity above 99 % and average nucleotide identity (ANI) values above 96 % among the strains, indicated that they belong to the same species. At the same time, the strains shared ANI values below 81 % and dDDH values below 24 % with all described Neisseria species. In the bac120 gene phylogenetic tree, the three strains clustered near Neisseria elongata and Neisseria bacilliformis in the Neisseria clade. However, the Neisseria clade is not monophyletic, and includes the type strains of Morococcus cerebrosus, Bergeriella denitrificans, Kingella potus, Uruburuella suis, and Uruburuella testudinis. Neisseria shayeganii clustered outside the clade with members of the genus Eikenella. Amino acid identity (AAI) values were calculated, and a threshold of 71 % was used to circumscribe the genus Neisseria. According to this proposed AAI threshold, strains 3986T, 51.81, and JF 2415 were placed within the genus Neisseria. The cells of the three strains were Gram-stain-negative diplococcobacilli and non-motile. Optimal growth on trypticase soy agar occurred at 37 °C and pH 8.5 in aerobic conditions. Notably, all strains exhibited indole production in the API-NH test, which is atypical for Neisseria and the family Neisseriaceae. The strains exhibited a common set of 68 peaks in their MALDI-TOF MS profiles, facilitating the swift and accurate identification of this species. Based on genotypic and phenotypic data, it is proposed that strains 3986T, 51.81, and JF 2415 represent a novel species within the genus Neisseria, for which the name Neisseria leonii sp. nov. is proposed (type strain 3986T=R726T=CIP 109994T=LMG 32907T).

Embolic necrosuppurative pneumonia in domestic cats induced by a novel Neisseria species.

Three cats, aged 2 to 11 years, presented to the University of Minnesota Veterinary Diagnostic Laboratory over a 3-year period following euthanasia or death due to respiratory distress. Thoracic radiographs revealed nodular, soft tissue opacities throughout the lung fields in all cases. On postmortem examination, approximately 60% to 80% of the lung parenchyma were expanded by multifocal to coalescing, well-demarcated, beige, semi-firm nodules. Histologically, large numbers of neutrophils, fewer macrophages, fibrin, and cellular and karyorrhectic debris effaced the pulmonary parenchyma. The inflammatory foci contained aggregates of gram-negative cocci. 16s rRNA Sanger sequencing and whole-genome sequencing identified the bacteria isolated from the lung of all cats under aerobic conditions as a novel Neisseria spp. Based on whole-genome sequence analysis, all 3 sequences shared 92.71% and 92.67% average nucleotide identity with closely related Neisseria animaloris NZ LR134440T and Neisseria animaloris GCA 002108605T, respectively. The in silico DNA-DNA hybridization identity compared to our isolates was 46.6% and 33.8% with strain DSM Neisseria zoodegmatis 21642 and strain DSM 21643, respectively. All 3 sequences have less than 95% average nucleotide identity and less than 70% DNA-DNA hybridization identity, suggesting that the 3 isolates are a novel species of the genus Neisseria. Infection with Neisseria spp. induces an embolic pneumonia in cats that radiographically and pathologically resembles a metastatic neoplastic process and should be considered among the etiologic differential diagnoses in cases of infectious pulmonary disease with a disseminated, nodular lung pattern.

Secretory expression of amylosucrase in Bacillus licheniformis through twin-arginine translocation pathway.

Amylosucrase (EC 2.4.1.4) is a versatile enzyme with significant potential in biotechnology and food production. To facilitate its efficient preparation, a novel expression strategy was implemented in Bacillus licheniformis for the secretory expression of Neisseria polysaccharea amylosucrase (NpAS). The host strain B. licheniformis CBBD302 underwent genetic modification through the deletion of sacB, a gene responsible for encoding levansucrase that synthesizes extracellular levan from sucrose, resulting in a levan-deficient strain, B. licheniformis CBBD302B. Neisseria polysaccharea amylosucrase was successfully expressed in B. licheniformis CBBD302B using the highly efficient Sec-type signal peptide SamyL, but its extracellular translocation was unsuccessful. Consequently, the expression of NpAS via the twin-arginine translocation (TAT) pathway was investigated using the signal peptide SglmU. The study revealed that NpAS could be effectively translocated extracellularly through the TAT pathway, with the signal peptide SglmU facilitating the process. Remarkably, 62.81% of the total expressed activity was detected in the medium. This study marks the first successful secretory expression of NpAS in Bacillus species host cells, establishing a foundation for its future efficient production. ONE-SENTENCE SUMMARY: Amylosucrase was secreted in Bacillus licheniformis via the twin-arginine translocation pathway.

Penicillin and Cefotaxime Resistance of Quinolone-Resistant Neisseria meningitidis Clonal Complex 4821, Shanghai, China, 1965-2020.

Clonal complex 4821 (CC4821) Neisseria meningitidis, usually resistant to quinolones but susceptible to penicillin and third-generation cephalosporins, is increasing worldwide. To characterize the penicillin-nonsusceptible (PenNS) meningococci, we analyzed 491 meningococci and 724 commensal Neisseria isolates in Shanghai, China, during 1965-2020. The PenNS proportion increased from 0.3% in 1965-1985 to 7.0% in 2005-2014 and to 33.3% in 2015-2020. Of the 26 PenNS meningococci, 11 (42.3%) belonged to the CC4821 cluster; all possessed mutations in penicillin-binding protein 2, mostly from commensal Neisseria. Genetic analyses and transformation identified potential donors of 6 penA alleles. Three PenNS meningococci were resistant to cefotaxime, 2 within the CC4821 cluster. With 96% of the PenNS meningococci beyond the coverage of scheduled vaccination and the cefotaxime-resistant isolates all from toddlers, quinolone-resistant CC4821 has acquired penicillin and cefotaxime resistance closely related to the internationally disseminated ceftriaxone-resistant gonococcal FC428 clone, posing a greater threat especially to young children.

Neisseria lisongii sp. nov. and Neisseria yangbaofengii sp. nov., isolated from the respiratory tracts of marmots.

Four Gram-stain-negative, oxidase-positive, non-motile, cocci-shaped bacteria strains (ZJ106T, ZJ104, ZJ785T and ZJ930) were isolated from marmot respiratory tracts. Phylogenetic analyses based on 16S rRNA genes, 53 ribosomal protein sequences and 441 core genes supported that all four strains belonged to the genus Neisseria with close relatives Neisseria weixii 10022T and Neisseria iguanae ATCC 51483T. Average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values were below the species-level thresholds (95-96 % for ANI, and 70 % for dDDH). The major fatty acids of all four strains were C16 : 1 ω7c /C16 : 1 ω6c, C16 : 0 and C18 : 1 ω9c. Major polar lipids were composed of diphosphatidylglycerol, phosphatidylethanolamine and phosphatidylglycerol. MK-8 was the major menaquinone. Based on Virulence Factor Database analysis, the four strains were found to contain NspA and PorB H-factor binding proteins that promote evasion of host immunity. Strains ZJ106T and ZJ104 contained structures similar to the capsule synthesis manipulator of Neisseria meningitidis. Based on phenotypic and phylogenetic evidence, we propose that strains ZJ106T and ZJ785T represent two novel species of the genus Neisseria, respectively, with the names Neisseria lisongii sp. nov. and Neisseria yangbaofengii sp. nov. The type strains are ZJ106T (=GDMCC 1.3111T=JCM 35323T) and ZJ785T (=GDMCC 1.1998T=KCTC 82336T).

Visualizing multistep elevator-like transitions of a nucleoside transporter.

Membrane transporters move substrates across the membrane by alternating access of their binding sites between the opposite sides of the membrane. An emerging model of this process is the elevator mechanism, in which a substrate-binding transport domain moves a large distance across the membrane. This mechanism has been characterized by a transition between two states, but the conformational path that leads to the transition is not yet known, largely because the available structural information has been limited to the two end states. Here we present crystal structures of the inward-facing, intermediate, and outward-facing states of a concentrative nucleoside transporter from Neisseria wadsworthii. Notably, we determined the structures of multiple intermediate conformations, in which the transport domain is captured halfway through its elevator motion. Our structures present a trajectory of the conformational transition in the elevator model, revealing multiple intermediate steps and state-dependent conformational changes within the transport domain that are associated with the elevator-like motion.

Neisseria montereyensis sp. nov., Isolated from Oropharynx of California Sea Lion (Zalophus californianus): Genomic, Phylogenetic, and Phenotypic Study.

A novel Neisseria strain, designated CSL10203-ORH2T, was isolated from the oropharynx of a wild California sea lion (Zalophus californianus) that was admitted to The Marine Mammal Center in California, USA. The strain was originally cultured from an oropharyngeal swab on BD Phenylethyl Alcohol (PEA) agar with 5% sheep blood under aerobic conditions. Phylogenetic analyses based on 16S rRNA, rplF, and rpoB gene sequences and the core genome sequences indicated that the strain was most closely related to only N. zalophi CSL 7565T. The average nucleotide identity and digital DNA-DNA hybridization values between strain CSL10203-ORH2T and the closely related species N. zalophi CSL 7565T were 89.84 and 39.70%, respectively, which were significantly lower than the accepted species-defined thresholds for describing novel prokaryotic species at the genomic level. Both type strains were phenotypically similar but can be easily and unambiguously distinguished between each other by the analysis of their housekeeping genes, e.g., rpoB, gyrB, or argF. The major fatty acids in both type strains were C12:0, C16:0, C16:1-c9, and C18:1-c11. Based on the genomic, phenotypic, and phylogenetic properties, the novel strain represents a novel species of the genus Neisseria, for which the name Neisseria montereyensis sp. nov. with the type strain CSL10203-ORH2T (= DSM 114706T = CCUG 76428T = NCTC 14721T) is proposed. The genome G + C content is 45.84% and the complete draft genome size is 2,310,535 bp.

Pathogenic Neisseria Bind the Complement Protein CFHR5 via Outer Membrane Porins.

Neisseria meningitidis and Neisseria gonorrhoeae are important human pathogens that have evolved to bind the major negative regulator of the complement system, complement factor H (CFH). However, little is known about the interaction of pathogens with CFH-related proteins (CFHRs) which are structurally similar to CFH but lack the main complement regulatory domains found in CFH. Insights into the role of CFHRs have been hampered by a lack of specific reagents. We generated a panel of CFHR-specific monoclonal antibodies and demonstrated that CFHR5 was bound by both pathogenic Neisseria spp. We showed that CFHR5 bound to PorB expressed by both pathogens in the presence of sialylated lipopolysaccharide and enhanced complement activation on the surface of N. gonorrhoeae. Our study furthered our understanding of the interactions of CFHRs with bacterial pathogens and revealed that CFHR5 bound the meningococcus and gonococcus via similar mechanisms.

Severe Dysbiosis and Specific Haemophilus and Neisseria Signatures as Hallmarks of the Oropharyngeal Microbiome in Critically Ill Coronavirus Disease 2019 (COVID-19) Patients.

BACKGROUND: At the entry site of respiratory virus infections, the oropharyngeal microbiome has been proposed as a major hub integrating viral and host immune signals. Early studies suggested that infections with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are associated with changes of the upper and lower airway microbiome, and that specific microbial signatures may predict coronavirus disease 2019 (COVID-19) illness. However, the results are not conclusive, as critical illness can drastically alter a patient's microbiome through multiple confounders. METHODS: To study oropharyngeal microbiome profiles in SARS-CoV-2 infection, clinical confounders, and prediction models in COVID-19, we performed a multicenter, cross-sectional clinical study analyzing oropharyngeal microbial metagenomes in healthy adults, patients with non-SARS-CoV-2 infections, or with mild, moderate, and severe COVID-19 (n = 322 participants). RESULTS: In contrast to mild infections, patients admitted to a hospital with moderate or severe COVID-19 showed dysbiotic microbial configurations, which were significantly pronounced in patients treated with broad-spectrum antibiotics, receiving invasive mechanical ventilation, or when sampling was performed during prolonged hospitalization. In contrast, specimens collected early after admission allowed us to segregate microbiome features predictive of hospital COVID-19 mortality utilizing machine learning models. Taxonomic signatures were found to perform better than models utilizing clinical variables with Neisseria and Haemophilus species abundances as most important features. CONCLUSIONS: In addition to the infection per se, several factors shape the oropharyngeal microbiome of severely affected COVID-19 patients and deserve consideration in the interpretation of the role of the microbiome in severe COVID-19. Nevertheless, we were able to extract microbial features that can help to predict clinical outcomes.

The emergence of the ceftriaxone-resistant Neisseria gonorrhoeae FC428 clone by transfer of resistance from an oral Neisseria subflava reservoir of resistance.

BACKGROUND: The ceftriaxone-resistant Neisseria gonorrhoeae FC428 clone was first discovered in Japan in 2015. OBJECTIVES: We investigated the possibility of horizontal gene transfer from Neisseria subflava harbouring the mosaic-like PBP-2 in the emergence of the FC428 clone. We also analysed whether there were fitness costs associated with the sustained international dissemination of the clone. METHODS: Sequencing of the penA gene in ceftriaxone-resistant N. subflava strains was performed. For transformation experiments between donor N. subflava and ciprofloxacin-resistant wild-type penA N. gonorrhoeae recipient, the full-length PCR amplification product of the penA gene, including DUS regions, was used as the donor DNA. Biological fitness of the transformants was measured by growth competition assays. The impact of QRDR and mtrR mutations, which have been reported as compensatory mutations, on fitness was also assessed. RESULTS: The penA mosaic allele of the FC428 clone showed 100%, 91.8%, and 89.8% homology, respectively, with penA genes of three ceftriaxone-resistant N. subflava strains, No. 30, No. 9 and No. 14. Results were consistent with homologous recombination with the donated penA mosaic allele. In co-cultures with the parent strain, transformants showed comparable growth indicating that a gyrA mutation compensates for the fitness cost of mosaic penA alleles. CONCLUSIONS: Our findings support the hypothesis that the FC428 clone was generated by transformation of the mosaic penA allele from oropharyngeal N. subflava to N. gonorrhoeae. Furthermore, it suggests that mutations in the gyrA QRDR region compensate for fitness costs and contribute to the continued transmission of the FC428 clone.

Global epidemiology of antimicrobial resistance in commensal Neisseria species: A systematic review.

BACKGROUND: Commensal Neisseria species (spp). represent an important reservoir of antimicrobial resistance genes for pathogenic Neisseria spp. In this systematic review, we aimed to assess the antimicrobial susceptibility of commensal Neisseria spp. and how this has evolved over time. We also aimed to assess if commensal Neisseria spp. showed intrinsic resistance to four antimicrobials - penicillin, azithromycin, ceftriaxone and ciprofloxacin. METHODS: Pubmed and Google Scholar were searched following the PRISMA guidelines. Articles reporting MICs of commensal Neisseria spp. were included according to inclusion/exclusion criteria, and the quality of the articles was assessed using a pre-designed tool. Individual and summary measures of penicillin, azithromycin, ceftriaxone and ciprofloxacin MICs were collected. Additional data was sought to perform a comparison between the MICs of pathogenic and commensal Neisseria spp. RESULTS: A total of 15 studies met our criteria.We found no evidence of intrinsic AMR in commensal Neisseria spp. We did find evidence of an increasing trend in MICs of commensal Neisseria spp. over time for all antimicrobials assessed. These findings were similar in various countries. Eight additional studies were included to compare pathogenic and commensal Neisseria spp. CONCLUSION: The MICs of commensal Neisseria spp. appear to be increasing in multiple countries. Surveillance of MICs in commensals could be used as an early warning system for antimicrobial resistance emergence in pathogens. Our findings underline the need for antibiotic stewardship interventions, particularly in populations with high antimicrobial consumption.

Genomic sequence of the non-pathogen Neisseria sp. strain MA1-1 with antibiotic resistance and virulence factors isolated from a head and neck cancer patient.

Recent research has claimed virulence factors or antimicrobial resistance in commensal or non-pathogenic Neisseria spp. This study aimed to isolate and analyze commensal microorganisms related to the genus Neisseria from the oral cavity of a patient with head and neck cancer. We successfully isolated strain MA1-1 and identified its functional gene contents. Although strain MA1-1 was related to Neisseria flava based on 16S rRNA gene sequence similarity, genomic relatedness analysis revealed that strain MA1-1 was closely related to Neisseria mucosa, reported as a commensal Neisseria species. The strain MA1-1 genome harbored genes for microaerobic respiration and the complete core metabolic pathway with few transporters for nutrients. A number of genes have been associated with virulence factors and resistance to various antibiotics. In addition, the comparative genomic analysis showed that most genes identified in the strain MA1-1 were shared with other Neisseria spp. including two well-known pathogens, Neisseria gonorrhoeae and Neisseria meningitidis. This indicates that the gene content of intra-members of the genus Neisseria has been evolutionarily conserved and is stable, with no gene recombination with other microbes in the host. Finally, this study provides more fundamental interpretations for the complete gene sequence of commensal Neisseria spp. and will contribute to advancing public health knowledge.

Sequential markerless genetic manipulations of species from the Neisseria genus.

The development of simple and highly efficient strategies for genetic modifications is essential for postgenetic studies aimed at characterizing gene functions for various applications. We sought to develop a reliable system for Neisseria species that allows for both unmarked and accumulation of multiple genetic modifications in a single strain. In this work, we developed and validated three-gene cassettes named RPLK and RPCC, comprising of an antibiotic resistance marker for positive selection, the phenotypic selection marker lacZ or mCherry, and the counterselection gene rpsL. These cassettes can be transformed with high efficiency across the Neisseria genus while significantly reducing the number of false positives compared with similar approaches. We exemplified the versatility and application of these systems by obtaining unmarked luminescent strains (knock-in) or mutants (knock-out) in different pathogenic and commensal species across the Neisseria genus in addition to the cumulative deletion of six loci in a single strain of Neisseria elongata.

Antimicrobial Peptides as a Promising Therapeutic Strategy for Neisseria Infections.

Antibiotic resistance is already widespread in the world, and it has become a great health problem. Therefore, comprehensive efforts are needed to minimize the resistance. The exploration of alternative therapies may offer a more targeted approach with less susceptibility to resistance. Even though antimicrobial peptides (AMPs) have been introduced as emerging antibiotic sources, they are not widely discussed in the literature. Since Neisseria infections show resistance to different types of antibiotics, the purpose of this review was to discuss the currently investigated AMPs with anti-Neisseria properties. In the present review, we provide an overview of 24 AMPs with in vitro anti-Neisseria properties.

Clinical study showing a lower abundance of Neisseria in the oral microbiome aligns with low birth weight pregnancy outcomes.

OBJECTIVES: The objective of this study was to examine the association between the oral microbiome and pregnancy outcomes, specifically healthy or preterm low birth weight (PLBW) in individuals with and without periodontal disease (PD). MATERIAL AND METHODS: In this prospective clinical trial, we recruited 186 pregnant women, 17 of whom exhibited PD and delivered PLBW infants (PD-PLBW group). Of the remaining women, 155 presented PD and delivered healthy infants; 18 of these subjects with similar periodontal condition and age matched to the PD-PLBW group, and they became the PD-HD group. From the total group, 11 women exhibited healthy gingiva and had a healthy delivery (HD) and healthy infants (H-HD group), and 3 exhibited healthy gingiva and delivered PLBW infants (H-PLBW group). Periodontal parameters were recorded, and subgingival plaque and serum were collected during 26-28 gestational weeks. For the plaque samples, microbial abundance and diversity were accessed by 16S rRNA sequencing. RESULTS: Women with PD showed an enrichment in the genus Porphyromonas, Treponema, and Filifactor, whereas women with healthy gingiva showed an enrichment in Streptococcus, Actinomyces, and Corynebacterium, independently of the birth status. Although no significant difference was found in the beta diversity between the 4 groups, women that had PLBW infants presented a significantly lower abundance of the genus Neisseria, independently of PD status. CONCLUSION: Lower levels of Neisseria align with preterm low birth weight in pregnant women, whereas a higher abundance of Treponema, Porphyromonas, Fretibacterium, and Filifactor and a lower abundance of Streptococcus may contribute to periodontal disease during pregnancy. CLINICAL RELEVANCE: The oral commensal Neisseria have potential in the prediction of PLBW.