Genus Abiotrophia Research Articles

Correlation between caries activity and salivary microbiota in preschool children.

Early childhood caries (ECC) is the most common chronic infectious oral disease in preschool children worldwide. It is closely related to the caries activity (CA) of children. However, the distribution characteristics of oral saliva microbiomes in children with different CA are largely underexplored. The aim of this study was to investigate the microbial community in saliva of preschool children with different CA and caries status, and to analyze the difference of microbial community in saliva of children with different CA and its correlation with ECC. Subjects were divided into 3 groups based on the Cariostat caries activity test: Group H, high CA (n=30); Group M, medium CA (n = 30); Group L, low CA (n=30). Questionnaire survey was used to explore the related influencing factors of CA. According to the caries status (on the basis of decayed mising filled teeth), these subjects were divided into caries-free group (dmft=0, n=19), caries-low group (0 < dmft ≤ 4, n=27) and caries-high group (dmft > 4, n=44). Microbial profiles of oral saliva were analyzed using 16S rRNA gene sequencing. There were significant differences in the microbial structure (P < 0.05). Scardovia and Selenomonas were the biomarkers of both H group and high caries group. The genus Abiotrophia and Lautropia were the biomarkers of both the L group and the low caries group, while the Lactobacillus and Arthrospira spp. were significantly enriched in the M group. The area under the ROC curve of the combined application of dmft score, age, frequency of sugary beverage intake, and the genus Scardovia, Selenomonas, and Campylobacter in screening children with high CA was 0.842. Moreover, function prediction using the MetaCyc database showed that there were significant differences in 11 metabolic pathways of salivary microbiota among different CA groups. Certain bacteria genera in saliva such as Scardovia and Selenomonas may be helpful in screening children with high CA.

The Oral Microbiome in Children with Black Stained Tooth

Black stain (BS) is a characteristic extrinsic discoloration, which occurs along the third cervical line of the buccal and/or lingual surfaces of teeth, particularly in the primary dentition of humans. BS is produced by oral bacteria and byproducts of saliva, but there is a controversy about related bacteria. The aim of this study was to identify the oral microbiome in tooth BS using pyrosequencing. It was hypothesized that the oral microbiome of BS in children might be related to black-pigment producing bacteria. Supragingival dental plaque was obtained from six children (mean 8.1 years) with BS and four children (mean 8.3 years) without BS. The bacterial metagenome was obtained by pyrosequencing. The BS group contained 348 operative taxonomic units (OTUs), whereas the control group had 293 OTUs. Microbial abundance and diversity were significantly higher in the BS group (p &lt; 0.05). In the heatmap, the correlation between samples was the same as the BS scale. At the genus level, six genera—Abiotrophia, Eikenella, Granulicatella, Neisseria, Porphyromonas and Streptococcus—were significantly different between the two groups (p &lt; 0.05). We suggested that compositional changes in the oral microbiome are essential, and several species in the genus Neisseria, Porphyromonas and Streptococcus may be major contributors for BS formation. Although the number of subjects was relatively limited, our study is the first species-level analysis of pyrosequencing data in BS formation.

Antimicrobial Susceptibilities of Oral Isolates of Abiotrophia and Granulicatella According to the Consensus Guidelines for Fastidious Bacteria.

Background: The genera Abiotrophia and Granulicatella, previously known as nutritionally variant streptococci (NVS), are fastidious bacteria requiring vitamin B6 analogs for growth. They are members of human normal oral microbiota, and are supposed to be one of the important pathogens for so-called “culture-negative” endocarditis. Methods: The type strains and oral isolates identified, by using both phenotypic profiles and the DNA–DNA hybridization method, were examined for susceptibilities to 15 antimicrobial agents including penicillin (benzylpenicillin, ampicillin, amoxicillin, and piperacillin), cephem (cefazolin, ceftazidime, ceftriaxone, and cefaclor), carbapenem (imipenem), aminoglycoside (gentamicin), macrolide (erythromycin), quinolone (ciprofloxacin), tetracycline (minocycline), glycopeptide (vancomycin), and trimethoprim-sulfamethoxazole complex. The minimum inhibitory concentration and susceptibility criterion were determined, according to the consensus guideline from the Clinical and Laboratory Standards Institute. Results: Isolates of Abiotrophia defectiva were susceptible to ampicillin, amoxicillin ceftriaxone, cefaclor, imipenem, ciprofloxacin, and vancomycin. Isolates of Granulicatella adiacens were mostly susceptible to benzylpenicillin, ampicillin, amoxicillin, cefazolin, ceftriaxone, imipenem, minocycline, and vancomycin. The susceptibility profile of Granulicatella elegans was similar to that of G. adiacens, and the susceptibility rate was higher than that of G. adiacens. Conclusions: Although Abiotrophia and Granulicatella strains are hardly distinguishable by their phenotypic characteristics, their susceptibility profiles to the antimicrobial agents were different among the species. Species-related differences in susceptibility of antibiotics should be considered in the clinical treatment for NVS related infections.

Infective Endocarditis by Rare Organism Granulicatella Adiacens

Infective endocarditis (IE) is a life-threatening infection of the cardiac valves especially in patients with preexisted valvular disease. Having a rheumatic heart disease, congenital heart disease, prosthetic valves or previous episodes of IE are some of the traditional risk factors for infective endocarditis (Hoen &amp; Duval, 2013).&#x0D; Although most cases were reported by streptococci especially streptococcus viridans, which is one of the commensal bacteria isolated from the mouth, some of the cases of IE can be caused by fastidious extracellular bacteria such as Abiotrophia, HACEK group bacteria, Clostridium, Brucella, Legionella, Mycobacterium, and Bartonella spp. These organisms need supplemented media, prolonged incubation time, and special culture conditions to grow and be isolated.&#x0D; Abiotrophia was reclassified in a new genus Granulicatella, as Granulicatella adiacens, balaenopterae, elegans and G. para adiacens. The genus Abiotrophia consists of only one species -A.defectiva.

Oral microbiome in HIV-associated periodontitis.

HIV-associated periodontal diseases (PD) could serve as a source of chronic inflammation. Here, we sought to characterize the oral microbial signatures of HIV+ and HIV- individuals at different levels of PD severity.This cross-sectional study included both HIV+ and HIV- patients with varying degrees of PD. Two tooth, 2 cheek, and 1 saliva samples were obtained for microbiome analysis. Mothur/SILVADB were used to classify sequences. R/Bioconductor (Vegan, PhyloSeq, and DESeq2) was employed to assess overall microbiome structure differences and differential abundance of bacterial genera between groups. Polychromatic flow cytometry was used to assess immune activation in CD4 and CD8 cell populations.Around 250 cheek, tooth, and saliva samples from 50 participants (40 HIV+ and 10 HIV-) were included. Severity of PD was classified clinically as None/Mild (N), Moderate (M), and Severe (S) with 18 (36%), 16 (32%), and 16 (32%) participants in each category, respectively. Globally, ordination analysis demonstrated clustering by anatomic site (R2 = 0.25, P < 0.001). HIV status and PD severity showed a statistically significant impact on microbiome composition but only accounted for a combined 2% of variation. HIV+ samples were enriched in genera Abiotrophia, Neisseria, Kingella, and unclassified Neisseriaceae and depleted in Leptotrichia and Selenomonas. The Neisseria genus was consistently enriched in HIV+ participants regardless of sampling site and PD level. Immune markers were altered in HIV+ participants but did not show association with the oral microbiome.HIV-associated changes in oral microbiome result in subtle microbial signatures along different stages of PD that are common in independent oral anatomic sites.

Oral microbiota distinguishes acute lymphoblastic leukemia pediatric hosts from healthy populations.

In leukemia, oral manifestations indicate aberrations in oral microbiota. Microbiota structure is determined by both host and environmental factors. In human hosts, how health status shapes the composition of oral microbiota is largely unknown. Taking advantage of advances in high-throughput sequencing, we compared the composition of supragingival plaque microbiota of acute lymphoblastic leukemia (ALL) pediatric patients with healthy controls. The oral microbiota of leukemia patients had lower richness and less diversity compared to healthy controls. Microbial samples clustered into two major groups, one of ALL patients and another of healthy children, with different structure and composition. Abundance changes of certain taxa including the Phylum Firmicutes, the Class Bacilli, the Order Lactobacillales, the Family Aerococcaceae and Carnobacteriaceae, as well as the Genus Abiotrophia and Granulicatella were associated with leukemia status. ALL patients demonstrated a structural imbalance of the oral microbiota, characterized by reduced diversity and abundance alterations, possibly involved in systemic infections, indicating the importance of immune status in shaping the structure of oral microbiota.

Granulicatella adiacens isolated from sterile body fluids: A case series from India

The genera Abiotrophia and Granulicatella spp. (previously known as nutritionally variant Streptococcus) are infrequently isolated from clinical specimens. Literature quotes that they account for about 56% of the infective endocarditis and bacteremia, and lesser in CNS infections (post instrumentation) and others. The objective of the study was to assess the clinical significance and outcome of the patients with laboratory isolations of <i>Granulicatella adiacens</i>. Case Series: We reviewed the clinical records from 201112 noting down the demographic details, identifiable risk factors, management of patients in whom <i>Granulicatella adiacens</i> was isolated. Seven cases of <i>Granulicatella adiacens</i> were reported. Five were children (<2 years) and two were male adults. Six strains were from blood and one was isolated from cerebrospinal fluid shunt fluid and were regarded as clinically significant. Pre-existing co-morbidities like nephrotic syndrome, premature birth and dysmorphism were noted in almost all the children. One of the patients had undergone invasive ventriculoperitoneal shunt insertion. All the patients except one (discharged against medical advice) recovered. Conclusion: The study describes the spectrum of infections by <i>Granulicatella adiacens</i>. <i>G. adiacens</i> can grow on routine sheep blood agar without pyridoxal supplementation in CO2 incubator when sub-cultured from automated blood culture bottles. This is one of the largest study from India.

Meningitis caused by Abiotrophia defectiva: case report and literature review

The genus Abiotrophia comprises fastidious Gram-positive bacteria previously classified as nutritionally variant streptococci (NVS). The isolation of NVS from the central nervous system (CNS) is very rare. We describe a case of meningitis due to Abiotrophia defectiva in a patient who underwent a total hip arthroplasty 4 days previously. It is possible that the organism could be introduced through the spinal anesthesia. We also review all cases of CNS infections caused by NVS.

Granulicatella infection: diagnosis and management

Granulicatella species, along with the genus Abiotrophia, were originally known as 'nutritionally variant streptococci'. They are a normal component of the oral flora, but have been associated with a variety of invasive infections in man and are most noted as a cause of bacterial endocarditis. It is often advised that Granulicatella endocarditis should be treated in the same way as enterococcal endocarditis. We review here the published data concerning diagnosis and treatment of Granulicatella infection, and include some observations from local cases, including four cases of endocarditis.

Endocardiac infectivity and binding to extracellular matrix proteins of oralAbiotrophiaspecies

Microorganisms of the genus Abiotrophia, formerly known as nutritionally variant streptococci, are members of the oral flora and often isolated from patients with endocarditis, but pathogenicity of oral Abiotrophia species has not been examined yet. In this study, 17 strains isolated from healthy human oral cavities and 7 reference strains (all derived from patients with endocarditis) of Abiotrophia spp. were tested for their abilities to cause infections in damaged heart tissues in catheterized rats and to adhere to extracellular matrix proteins in vitro. The reference strains of A. defectiva and A. adiacens showed high infectivities in the rats. Four oral isolates of these two species showed similarly high infectivities and three had moderate infectivities. Most of 10 oral strains of A. para-adiacens and A. elegans were found to be generally less infective. The highly infective A. adiacens strains showed markedly high fibronectin-binding capacity, suggesting a possible relationship between the fibronectin-binding capacity and damaged heart tissue infectivity of the Abiotrophia species. A. defectiva strains which were also highly infective had moderate levels of binding to fibronectin and other extracellular matrix proteins. Most of A. para-adiacens and A. elegans strains showed low or negligible binding capacities to any extracellular matrix proteins tested.

Endocardiac infectivity and binding to extracellular matrix proteins of oral Abiotrophia species

Microorganisms of the genus Abiotrophia, formerly known as nutritionally variant streptococci, are members of the oral flora and often isolated from patients with endocarditis, but pathogenicity of oral Abiotrophia species has not been examined yet. In this study, 17 strains isolated from healthy human oral cavities and 7 reference strains (all derived from patients with endocarditis) of Abiotrophia spp. were tested for their abilities to cause infections in damaged heart tissues in catheterized rats and to adhere to extracellular matrix proteins in vitro. The reference strains of A. defectiva and A. adiacens showed high infectivities in the rats. Four oral isolates of these two species showed similarly high infectivities and three had moderate infectivities. Most of 10 oral strains of A. para-adiacens and A. elegans were found to be generally less infective. The highly infective A. adiacens strains showed markedly high fibronectin-binding capacity, suggesting a possible relationship between the fibronectin-binding capacity and damaged heart tissue infectivity of the Abiotrophia species. A. defectiva strains which were also highly infective had moderate levels of binding to fibronectin and other extracellular matrix proteins. Most of A. para-adiacens and A. elegans strains showed low or negligible binding capacities to any extracellular matrix proteins tested.

Genetic heterogeneities and phenotypic characteristics of strains of the genus Abiotrophia and proposal of Abiotrophia para-adiacens sp. nov.

The genus Abiotrophia represents a heterogeneous group of fastidious cocci that show a dependence on pyridoxal hydrochloride analogs for growth. The genetic heterogeneity in the genus Abiotrophia was examined by DNA-DNA hybridization, PCR assay of genomic DNA sequences, and restriction fragment length polymorphism and sequence homology analyses of the PCR-amplified 16S rRNA gene. Nine type or reference strains of Abiotrophia defectiva, Abiotrophia adiacens, and Abiotrophia elegans and 36 oral Abiotrophia isolates including the ones presumptively identified as Gemella morbillorum by the rapid ID32 STREP system were divided into four groups: A. defectiva (genotype 1), A. adiacens (genotype 2), A. elegans (genotype 4), and a fourth species (genotype 3) which we propose be named Abiotrophia para-adiacens sp. nov. A PCR assay specific for detection and identification of the novel Abiotrophia species was developed. A. para-adiacens generally produced beta-glucosidase but did not produce alpha- or beta-galactosidase or arginine dihydrolase, did not ferment, trehalose, pullulan, or tagatose, and was serotype IV, V, or VI. Thus, it was distinguished phenotypically from A. adiacens, A. elegans, and A. defectiva as well as, apparently, from the recently described species Abiotrophia balaenopterae sp. nov., which produces arginine dihydrolase and which ferments pullulan but not sucrose (P. A. Lawson et al., Int. J. Syst. Bacteriol. 49:503-506, 1999). Strain ATCC 27527, currently listed as G. morbillorum, was a member of the species A. para-adiacens.

The genus Abiotrophia (Kawamura et al.) is not monophyletic: proposal of Granulicatella gen. nov., Granulicatella adiacens comb. nov., Granulicatella elegans comb. nov. and Granulicatella balaenopterae comb. nov.

The genus Abiotrophia currently includes four species, Abiotrophia defectiva, Abiotrophia adiacens, Abiotrophia balaenopterae and Abiotrophia elegans. Recent 16S rRNA gene sequencing studies have demonstrated that the genus is not monophyletic and is in need of taxonomic revision. Phylogenetically, the genus Abiotrophia consists of two distinct lines, A. defectiva, the type species of the genus, and a robust group consisting of A. adiacens, A. balaenopterae and A. elegans. Therefore, it is formally proposed that the genus Abiotrophia should be restricted to A. defectiva and that A. adiacens, A. balaenopterae and A. elegans should be reclassified in a new genus, Granulicatella, as Granulicatella adiacens comb. nov., Granulicatella balaenopterae comb. nov. and Granulicatella elegans comb. nov.

Transfer of Streptococcus adjacens and Streptococcus defectivus to Abiotrophia gen. nov. as Abiotrophia adiacens comb. nov. and Abiotrophia defectiva comb. nov., respectively.

We performed this study to determine the 16S rRNA sequences of the type strains of Streptococcus adjacens and Streptococcus defectivus and to calculate the phylogenetic distances between these two nutritionally variant streptococci (NVS) and other members of the genus Streptococcus. S. adjacens and S. defectivus belonged to one cluster, but this cluster was not closely related to other streptococcal species. A comparative analysis of the sequences of these organisms and other low-G+C-content gram-positive bacteria revealed that the two NVS species formed a distinct cluster and were only remotely related to the Aerococcus and Carnobacterium clusters. The highest level of homology (93.7%) was found between S. adjacens and Carnobacterium divergens. Carnobacterium species have meso-diaminopimelic acid in their cell walls, but S. adjacens and S. defectivus have L-lysine as the diamino acid at position 3 in their peptidoglycan tetrapeptides. On the basis of our findings and the results of previous phenotypic studies, we propose that the NVS species should be placed in a new genus, the genus Abiotrophia, as Abiotrophia adiacens comb. nov. and Abiotrophia defectiva comb. nov.