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Science (New York, N.Y.) Apr 2023Type VI CRISPR-Cas systems use RNA-guided ribonuclease (RNase) Cas13 to defend bacteria against viruses, and some of these systems encode putative membrane proteins that...
Type VI CRISPR-Cas systems use RNA-guided ribonuclease (RNase) Cas13 to defend bacteria against viruses, and some of these systems encode putative membrane proteins that have unclear roles in Cas13-mediated defense. We show that Csx28, of type VI-B2 systems, is a transmembrane protein that assists to slow cellular metabolism upon viral infection, increasing antiviral defense. High-resolution cryo-electron microscopy reveals that Csx28 forms an octameric pore-like structure. These Csx28 pores localize to the inner membrane in vivo. Csx28's antiviral activity in vivo requires sequence-specific cleavage of viral messenger RNAs by Cas13b, which subsequently results in membrane depolarization, slowed metabolism, and inhibition of sustained viral infection. Our work suggests a mechanism by which Csx28 acts as a downstream, Cas13b-dependent effector protein that uses membrane perturbation as an antiviral defense strategy.
Topics: CRISPR-Cas Systems; Cryoelectron Microscopy; Membrane Proteins; RNA, Viral; Bacterial Proteins; Endodeoxyribonucleases; CRISPR-Associated Proteins; RNA Cleavage; Bacteriophages; Bacteriophage lambda; Escherichia coli; Prevotella
PubMed: 37104586
DOI: 10.1126/science.abm1184 -
Veterinary Microbiology May 2017Periodontitis is a polymicrobial infectious disease that causes occlusion change, tooth loss, difficulty in rumination, and premature culling of animals. This study...
Periodontitis is a polymicrobial infectious disease that causes occlusion change, tooth loss, difficulty in rumination, and premature culling of animals. This study aimed to detect species of the genera Porphyromonas and Prevotella present in the periodontal pocket of sheep with lesions deeper than 5mm (n=14) and in the gingival sulcus of animals considered periodontally healthy (n=20). The presence of microorganisms was evaluated by polymerase chain reaction (PCR) using specific primers for Porphyromonas asaccharolytica, Porphyromonas endodontalis, Porphyromonas gingivalis, Porphyromonas gulae, Prevotella buccae, Prevotella intermedia, Prevotella loescheii, Prevotella melaninogenica, Prevotella nigrescens, Prevotella oralis, and Prevotella tannerae. Prevalence and risk analysis were performed using Student's t-test and Spearman's correlation. Among the Prevotella and Porphyromonas species detected in the periodontal lesions of sheep, P. melaninogenica (85.7%), P. buccae (64.3%), P. gingivalis (50%), and P. endodontalis (50%) were most prevalent. P. gingivalis (15%) and P. oralis (10%) prevailed in the gingival sulcus. P. gulae and P. tannerae were not detected in the 34 samples studied. Data evaluation by t-test verified that occurrence of P. asaccharolytica, P. endodontalis, P. gingivalis, P. buccae, P. intermedia, P. melalinogenica, and P. nigrescens correlated with sheep periodontitis. The findings of this study will be an important contribution to research on pathogenesis of sheep periodontitis and development of its control measures.
Topics: Animals; Bacteria, Anaerobic; Biofilms; Periodontal Pocket; Periodontitis; Polymerase Chain Reaction; Porphyromonas; Prevotella; Sheep; Sheep Diseases
PubMed: 28619155
DOI: 10.1016/j.vetmic.2017.03.032 -
The Journal of Antimicrobial... Apr 2024Recently, reports on antimicrobial-resistant Bacteroides and Prevotella isolates have increased in the Netherlands. This urged the need for a surveillance study on the...
Antimicrobial susceptibility profile of clinically relevant Bacteroides, Phocaeicola, Parabacteroides and Prevotella species, isolated by eight laboratories in the Netherlands.
OBJECTIVES
Recently, reports on antimicrobial-resistant Bacteroides and Prevotella isolates have increased in the Netherlands. This urged the need for a surveillance study on the antimicrobial susceptibility profile of Bacteroides, Phocaeicola, Parabacteroides and Prevotella isolates consecutively isolated from human clinical specimens at eight different Dutch laboratories.
METHODS
Each laboratory collected 20-25 Bacteroides (including Phocaeicola and Parabacteroides) and 10-15 Prevotella isolates for 3 months. At the national reference laboratory, the MICs of amoxicillin, amoxicillin/clavulanic acid, piperacillin/tazobactam, meropenem, imipenem, metronidazole, clindamycin, tetracycline and moxifloxacin were determined using agar dilution. Isolates with a high MIC of metronidazole or a carbapenem, or harbouring cfiA, were subjected to WGS.
RESULTS
Bacteroides thetaiotaomicron/faecis isolates had the highest MIC90 values, whereas Bacteroides fragilis had the lowest MIC90 values for amoxicillin/clavulanic acid, piperacillin/tazobactam, meropenem, imipenem and moxifloxacin. The antimicrobial profiles of the different Prevotella species were similar, except for amoxicillin, for which the MIC50 ranged from 0.125 to 16 mg/L for Prevotella bivia and Prevotella buccae, respectively. Three isolates with high metronidazole MICs were sequenced, of which one Bacteroides thetaiotaomicron isolate harboured a plasmid-located nimE gene and a Prevotella melaninogenica isolate harboured a nimA gene chromosomally.Five Bacteroides isolates harboured a cfiA gene and three had an IS element upstream, resulting in high MICs of carbapenems. The other two isolates harboured no IS element upstream of the cfiA gene and had low MICs of carbapenems.
CONCLUSIONS
Variations in resistance between species were observed. To combat emerging resistance in anaerobes, monitoring resistance and conducting surveillance are essential.
Topics: Humans; Meropenem; Moxifloxacin; Netherlands; Metronidazole; Laboratories; Bacteroides; Anti-Bacterial Agents; Carbapenems; Bacteroides fragilis; Imipenem; Anti-Infective Agents; Microbial Sensitivity Tests; Piperacillin; Tazobactam; Prevotella; Amoxicillin; Clavulanic Acid
PubMed: 38394460
DOI: 10.1093/jac/dkae043 -
Archive of Clinical Cases 2023is a gram-negative obligate anaerobe mainly associated with infections of odontogenic origin. Non-oral monomicrobial infection by these obligate anaerobic bacteria is...
is a gram-negative obligate anaerobe mainly associated with infections of odontogenic origin. Non-oral monomicrobial infection by these obligate anaerobic bacteria is rare. Only a few cases of monomicrobial non-oral infections by have been reported in the literature. We are reporting a case of unilateral complicated pleural empyema in a patient with bronchial asthma infected by . Pleural fluid aerobic culture and blood culture reports were sterile. No acid-fast bacilli were detected by Acid Fast Bacilli (AFB) staining, and cartridge-based nucleic acid assay test (CBNAAT) reports were negative for . The isolate, was found susceptible to Metronidazole (MIC = 3 μg/ml) and resistant to Clindamycin (MIC = 256 μg/ml). In view of rising trends of antimicrobial resistance among anaerobes, it is recommended to perform anaerobic culture and sensitivity testing in clinically suspected cases of pleuropulmonary infection for appropriate diagnosis and optimal patient management. Clindamycin should be used with caution for empiric treatment.
PubMed: 38026109
DOI: 10.22551/2023.41.1004.10263 -
Cureus May 2023Necrotizing infections of deep neck spaces are a group of life-threatening infectious diseases acquired through trauma or as a descending infection from an odontogenic...
Necrotizing infections of deep neck spaces are a group of life-threatening infectious diseases acquired through trauma or as a descending infection from an odontogenic source. The isolation of pathogens is unusual because of the anaerobic nature of the infection; however, one way to achieve this is through the use of automated microbiological methods like matrix-assisted laser desorption/ionization and time-of-flight (MALDI-TOF) following standard microbiology protocols for analyzing samples from potential anaerobic infections. We present a case of a patient without risk factors for descending necrotizing mediastinitis with isolation managed at the intensive care unit with a multidisciplinary team. We present our approach and how we successfully treat this complicated infection.
PubMed: 37398802
DOI: 10.7759/cureus.39703 -
Clinical and Diagnostic Laboratory... Jul 1997Oral Prevotella and Capnocytophaga species, regularly isolated from periodontal pockets and associated with extraoral infections, secret specific immunoglobulin A1...
Oral Prevotella and Capnocytophaga species, regularly isolated from periodontal pockets and associated with extraoral infections, secret specific immunoglobulin A1 (IgA1) proteases cleaving human IgA1 in the hinge region into intact Fab and Fc fragments. To investigate whether these enzymes are subject to inhibition in vivo in humans, we tested 34 sera from periodontally diseased and healthy individuals in an enzyme-linked immunosorbent assay for the presence and titers of inhibition of seven Prevotella and Capnocytophaga proteases. All or nearly all of the sera inhibited the IgA1 protease activity of Prevotella buccae, Prevotella oris, and Prevotella loescheii. A minor proportion of the sera inhibited Prevotella buccalis, Prevotella denticola, and Prevotella melaninogenica IgA1 proteases, while no sera inhibited Capnocytophaga ochracea IgA1 protease. All inhibition titers were low, ranging from 5 to 55, with titer being defined as the reciprocal of the dilution of serum causing 50% inhibition of one defined unit of protease activity. No correlation between periodontal disease status and the presence, absence, or titer of inhibition was observed. The nature of the low titers of inhibition in all sera of the IgA1 proteases of P. buccae, P. oris, and P. loescheii was further examined. In size exclusion chromatography, inhibitory activity corresponded to the peak volume of IgA. Additional inhibition of the P. oris IgA1 protease was found in fractions containing both IgA and IgG. Purification of the IgG fractions of five sera by passage of the sera on a protein G column resulted in recovery of inhibitory IgG antibodies against all three IgA1 proteases, with the highest titer being for the P. oris enzyme. These finding indicate that inhibitory activity is associated with enzyme-neutralizing antibodies.
Topics: Adolescent; Adult; Aged; Antibodies, Bacterial; Binding, Competitive; Capnocytophaga; Humans; Immunoglobulin A; Immunoglobulin G; Middle Aged; Periodontal Diseases; Prevotella; Serine Endopeptidases; Serine Proteinase Inhibitors
PubMed: 9220164
DOI: 10.1128/cdli.4.4.458-464.1997 -
Cell Reports Mar 2019Type VI CRISPR-Cas systems contain programmable single-effector RNA-guided RNases, including Cas13b, one of the four known family members. Cas13b, which has been used...
Type VI CRISPR-Cas systems contain programmable single-effector RNA-guided RNases, including Cas13b, one of the four known family members. Cas13b, which has been used for both RNA editing and nucleic acid detection, is unique among type VI CRISPR effectors in its linear domain architecture and CRISPR RNA (crRNA) structure. Here, we report the crystal structure of Prevotella buccae Cas13b (PbuCas13b) bound to crRNA at 1.65 Å resolution. This structure, combined with biochemical experiments assaying the stability, kinetics, and function of Cas13b, provides a mechanistic model for Cas13b target RNA recognition and identifies features responsible for target and cleavage specificity. Based on these observations, we generated Cas13b variants with altered cleavage preferences, which may expand the utility of nuclease-based RNA detection assays and other applications of Cas13b in mammalian cells.
Topics: Bacterial Proteins; CRISPR-Cas Systems; Crystallography, X-Ray; Endonucleases; Enzyme Stability; Prevotella; Protein Binding; Protein Domains; RNA; Substrate Specificity
PubMed: 30917325
DOI: 10.1016/j.celrep.2019.02.094 -
Head & Face Medicine Sep 2013To detect predominant bacteria associated with radicular cysts and discuss in light of the literature.
PURPOSE
To detect predominant bacteria associated with radicular cysts and discuss in light of the literature.
MATERIAL AND METHODS
Clinical materials were obtained from 35 radicular cysts by aspiration. Cultures were made from clinical materials by modern laboratory techniques, they underwent microbiologic analysis.
RESULTS
The following are microorganisms isolated from cultures: Streptococcus milleri Group (SMG) (23.8%) [Streptococcus constellatus (19.1%) and Streptococcus anginosus (4.7%)], Streptococcus sanguis (14.3%), Streptococcus mitis (4.7%), Streptococcus cremoris (4.7%), Peptostreptococcus pevotii (4.7%), Prevotella buccae (4.7%), Prevotella intermedia (4.7%), Actinomyces meyeri (4.7%), Actinomyces viscosus (4.7%), Propionibacterium propionicum (4.7%), Bacteroides capillosus (4.7%), Staphylococcus hominis (4.7%), Rothia denticariosa (4.7%), Gemella haemolysans (4.7%), and Fusobacterium nucleatum (4.7%).
CONCLUSIONS
Results of this study demonstrated that radicular cysts show a great variety of anaerobic and facultative anaerobic bacterial flora. It was observed that all isolated microorganisms were the types commonly found in oral flora. Although no specific microorganism was found, Streptococcus spp. bacteria (47.5%) - especially SMG (23.8%) - were predominantly found in the microorganisms isolated. Furthermore, radicular cysts might be polymicrobial originated. Although radicular cyst is an inflammatory cyst, some radicular cyst fluids might be sterile.
Topics: Adult; Bacteria, Anaerobic; Female; Humans; Male; Mandibular Diseases; Maxillary Diseases; Microbiological Techniques; Mouth Mucosa; Radicular Cyst; Young Adult
PubMed: 24011184
DOI: 10.1186/1746-160X-9-25 -
BMJ Case Reports Jan 2022Torticollis in children can be a sign of a potentially dangerous disease; the correct diagnosis is not always obvious on history and physical examination. The use of...
Torticollis in children can be a sign of a potentially dangerous disease; the correct diagnosis is not always obvious on history and physical examination. The use of point-of-care ultrasound (POCUS) helps to limit the differential diagnosis and direct appropriate further laboratory and radiology-performed evaluation. We present a case of a 10-year-old child whose deep neck infection (DNI) was timely diagnosed in the paediatric emergency department by early use of POCUS and drained under POCUS guidance after admission to the hospital. The culture from the fluid grew This case demonstrates that DNIs occur in children with acute acquired torticollis, even without fever and demonstrates the importance of early use of POCUS in cases where DNI is a potential diagnosis. Moreover, this case emphasises the importance of microbiological identification of DNIs that can be the key to successful treatment.
Topics: Child; Emergency Service, Hospital; Humans; Neck; Point-of-Care Systems; Torticollis; Ultrasonography
PubMed: 34992062
DOI: 10.1136/bcr-2021-244331 -
Mikrobiyoloji Bulteni Apr 2020Prevotella species, being members of the human microbiota, are obligate anaerobic gram-negative bacteria. These organisms may cause opportunistic infections, including...
Prevotella species, being members of the human microbiota, are obligate anaerobic gram-negative bacteria. These organisms may cause opportunistic infections, including specific oral infections, local or systemic infections. A significant increase of resistance to some antimicrobials has been detected among Prevotella species. The frequency of resistance vary among isolates from different infection sources and between geographic locations. The knowledge about the antimicrobial susceptibility patterns of different Prevotella species is limited in Turkey. Providing the antimicrobial susceptibility data of these bacteria is very important for effective empirical treatment. In this study, we aimed to determine susceptibility data for 12 antimicrobial agents against Prevotella strains originating from human infections, collected in two centers in Turkey. A total of 118 Prevotella strains, isolated from different clinical samples in Marmara University Faculty of Medicine Medical Microbiology and Istanbul University Faculty of Dentistry Oral Microbiology Laboratories between January 2014-December 2017, were tested. Organisms were identified by using MALDI-TOF MS and by 16S rRNA gene sequencing. Minimal inhibitor concentrations of ampicillin, ampicillin-sulbactam, piperacillin-tazobactam, cefoxitin, meropenem, imipenem, clindamycin, tetracycline, tigecycline, moxifloxacin and metronidazole were determined using gradiyent test methodology (E-test; bioMerieux, France) and the European Committee on Antimicrobial Susceptibility Testing, Clinical and Laboratory Standards Institute and Food and Drug Administration guidelines were used for interpretation. Thirteen different Prevotella species were identified, Prevotella bivia and Prevotella nigrescens were the most prevalent species (n= 21) followed by Prevotella buccae (n= 19). All Prevotella strains were susceptible to piperacillin-tazobactam, cefoxitin, meropenem, imipenem and tigecycline. A total of 2 (1.7%) isolates were resistant to metronidazole and 1 (0.8%) isolate was intermediately resistant to ampicillin/sulbactam. The frequency of resistant isolates against ampicillin, clindamycin, tetracycline and moxifloxacin were 57.6%, 36.4%, 18% and 16.3%, respectively. In conclusion, piperacillin/tazobactam, cefoxitin, and tigecycline displayed high in vitro activity against Prevotella spp. and they all remained good candidates for empiric therapy. Imipenem and meropenem were also found to be very active, but the usage of carbapenems should be reserved for serious mixed infections, potentially accompanied by other resistant organisms. Intermediate resistance to ampicillinsulbactam and the resistance against metronidazole emphasized the need of periodic monitoring of their susceptibility patterns. The high rates of non-susceptibility to ampicillin, clindamycin, tetracycline and moxifloxacin indicated that these antimicrobials should not be used for treatment of infections without prior antimicrobial susceptibility testing.
Topics: Anti-Bacterial Agents; Bacteria, Anaerobic; Bacteroidaceae Infections; Humans; Microbial Sensitivity Tests; Prevotella; RNA, Ribosomal, 16S; Turkey
PubMed: 32723280
DOI: 10.5578/mb.69309