OBJECTIVE: To construct a model of Enterococcus faecalis (E. faecalis) infection in dentinal tubules by gradient centrifugation and to evaluate the antibacterial effect of low-temperature plasma on E. faecalis in dentinal tubules. METHODS: Standard dentin blocks of 4 mm×4 mm×2 mm size were prepared from single root canal isolated teeth without caries, placed in the E. faecalis bacterial solution, centrifuged in gradient and incubated for 24 h to establish the model of dentinal tubule infection with E. faecalis. The twenty dentin blocks of were divided into five groups, low-temperature plasma jet treatment for 0, 5 and 10 min, calcium hydroxide paste sealing for 7 d and 2% chlorhexidine gel sealing for 7 d. Scanning electron microscopy and confocal laser scanning microscope were used to assess the infection in the dentinal tubules and the antibacterial effect of low-temperature plasma. RESULTS: The results of scanning electron microscopy and confocal laser scanning microscopy showed that after 24 h of incubation by gradient centrifugation, E. faecalis could fully enter the dentinal tubules to a depth of more than 600μm indicating that this method was time-saving and efficient and could successfully construct a model of E. faecalis infection in dentinal tubules. Low-temperature plasma could enter the dentinal tubules and play a role, the structure of E. faecalis was still intact after 5 min of low-temperature plasma treatment, with no obvious damage, and after 10 min of low-temperature plasma treatment, the surface morphology of E. faecalis was crumpled and deformed, the cell wall was seriously collapsed, and the normal physiological morphology was damaged indicating that the majority of E. faecalis was killed in the dentinal tubules. The antibacterial effect of low-temperature plasma treatment for 10 min exceeded that of the calcium hydroxide paste sealing for 7 d and the 2% chlorhexidine gel sealing for 7 d. These two chemicals had difficulty entering deep into the dentinal tubules, and therefore only had a few of antibacterial effect on the bacterial biofilm on the root canal wall, and there was also no significant damage to the E. faecalis bacterial structure. CONCLUSION Gradient centrifugation could establish the model of E. faecalis dentin infection successfully. Low-temperature plasma treatment for 10 min could kill E. faecalis in dentinal tubules effectively, which is superior to the calcium hydroxide paste sealing for 7 d and the 2% chlorhexidine gel sealing for 7 d.
Chlorhexidine/pharmacology* ; Calcium Hydroxide/pharmacology* ; Enterococcus faecalis/physiology* ; Temperature ; Dentin ; Biofilms ; Anti-Bacterial Agents/pharmacology* ; Root Canal Irrigants/pharmacology* ; Dental Pulp Cavity

Root canal therapy is the common treatment for endodontic infections. Successful root canal therapy depends on favorable root canal preparation, root canal medication and three-dimensional obturation of the root canal system. The key to successful root canal therapy is to prevent re-infection of the highly complex root canal systems by removing infecious biofilms and bacterial toxins in the root canal system. The present paper reviews the pathogenic mechanism of the Enterococcus faecalis in the harsh environment of root canal system, the inflammation and immunity of refractory periapical periodontitis and the progress of infection control methods.
Dental Pulp Cavity ; Enterococcus faecalis ; Humans ; Periapical Periodontitis/therapy* ; Persistent Infection ; Root Canal Irrigants ; Root Canal Preparation ; Root Canal Therapy

ABSTRACT The goal of endodontic treatment is to prevent and control of pulp and periradicular infections. Calcium hydroxide has a beneficial biological property as an intracanal medicament and can be combined with cresotin to disinfect bacteria in root canals, especially Enterococcus faecalis (E. faecalis) which is the most frequently isolated strain in the root canals. The aim of this study was to investigate in vitro the antimicrobial activity of calcium hydroxide, cresotin, and combination calcium hydroxide and cresotin (Ca[OH]2+Cresotin, 1:1 and 1:2) against E. faecalis. Antibacterial activity was determined by the agar diffusion method. The test medicaments were placed inside the hole that made in the inoculated agar medium. The zone of growth inhibition was measured and recorded after incubation for each plate, and the result was analysed statistically with ANOVA. The in vitro antimicrobial effects of combination calcium hydroxide and cresotin (Ca[OH]2+Cresotin, 1:2) has more prominent antimicrobial activity than others, and calcium hydroxide is more effective than cresotin alone. The antimicrobial activity of combined calcium hydroxide and cresotin is more effective in killing E. faecalis in comparison to the other treatments.
Calcium Hydroxide--therapeutic use ; Root Canal Therapy ; Enterococcus faecalis

BACKGROUND: The isolation of carbapenemase-producing Enterobacteriaceae (CPE) has become increasingly common. Continuous surveillance for these organisms is essential because their infections are closely related to outbreaks of illness and are associated with high mortality rates. The aim of this study was to develop and evaluate multiplex PCR as a means of detecting several important CPE genes simultaneously. METHODS: We aimed to develop a multiplex PCR that could detect seven CPE genes simultaneously. The multiplex PCR was composed of seven primer sets for the detection of KPC, IMP, VIM, NDM-1, GES, OXA-23, and OXA-48. We designed different PCR product sizes of at least 100 bp. We evaluated the performance of this new test using 69 CPE-positive clinical isolates. Also, we confirmed the specificity to rule out false-positive reactions by using 71 carbapenem-susceptible clinical strains. RESULTS: A total of 69 CPE clinical isolates showed positive results and were correctly identified as KPC (N=14), IMP (N=13), OXA-23 (N=12), OXA-48 (N=11), VIM (N=9), GES (N=5), and NDM (N=5) by the multiplex PCR. All 71 carbapenem-susceptible clinical isolates, including Enterococcus faecalis , Escherichia coli, Klebsiella pneumoniae, Acinetobacter baumannii, and Pseudomonas aeruginosa, showed negative results. CONCLUSION: This multiplex PCR can detect seven CPE genes at a time and will be useful in clinical laboratories.
Acinetobacter baumannii ; Disease Outbreaks ; Enterobacteriaceae ; Enterococcus faecalis ; Escherichia coli ; Klebsiella pneumoniae ; Mortality ; Multiplex Polymerase Chain Reaction ; Polymerase Chain Reaction ; Pseudomonas aeruginosa ; Sensitivity and Specificity

BACKGROUND: Enterococcus faecalis strains with low-level resistance to linezolid (an oxazolidinone antibiotic) have become common. No large-scale study has examined the underlying mechanisms in linezolid-resistant E. faecalis (LRE) strains. We investigated these mechanisms and molecular characteristics in Chongqing, China. METHODS: A total of 1,120 non-duplicated E. faecalis strains collected from August 2014 to June 2017 underwent drug susceptibility testing. LRE strains were screened for optrA, cfr, and mutations in the 23S rRNA and ribosomal proteins L3 and L4 by PCR amplification and sequencing. Multi-locus sequence typing (MLST) and pulsed-field gel electrophoresis (PFGE) were used for epidemiological analysis. RESULTS: All 43 low-level LRE strains (minimum inhibitory concentration: 8–16 mg/L) harbored optrA; cfr and 23S rRNA mutations were not detected. Novel mutations in the ribosomal proteins L3 and L4—one deletion (Q103del) and four substitutions (S113L, T35A, I98V, and N79D)—were identified. Novel amino acid substitutions at positions E60K, G197D, and T285P of the OptrA protein were observed. MLST revealed 20 types of LRE strains; the most common type was ST16 (32.6%). PFGE showed 14 strains of ST16 with unique banding patterns. Eight novel sequence types (ST823 to ST830) and one allele (gki95) were identified for the first time in China. CONCLUSIONS: optrA plays an important role in linezolid resistance and may serve as a marker for resistance screening. Since the L3 and L4 mutations did not simultaneously occur in the same strain, they play a negligible role in linezolid resistance. Epidemiological investigation suggested that the LRE cases were sporadic.
Alleles ; Amino Acid Substitution ; China* ; Electrophoresis, Gel, Pulsed-Field ; Enterococcus faecalis* ; Enterococcus* ; Epidemiology ; Linezolid ; Mass Screening ; Molecular Epidemiology* ; Polymerase Chain Reaction ; Ribosomal Proteins

No abstract available.
Endophthalmitis ; Enterococcus faecalis ; Enterococcus

BACKGROUND: Antimicrobial resistance (AMR) is an issue not only with regard to public health, but also in terms of economic impact. AMR surveillance has mainly been carried out in general hospitals, and not in nursing hospitals. This study was conducted to investigate the AMR rate for bacterial strains isolated from nursing hospital samples.METHODS: Antimicrobial susceptibility testing (AST) results from a total of 23,518 bacterial isolates recovered from clinical specimens taken in 61 nursing hosals were analyzed. AST was conducted using Vitek 2 with AST cards specific for the bacterial strains.RESULTS: A total of 19,357 Gram-negative and 4,161 Gram-positive bacterial strains were isolated. Pseudomonas aeruginosa (n=6,384) and Escherichia coli (n=5,468) were the most prevalent bacterial species and, among Gram-positive bacteria, Staphylococcus aureus (n=1,565) was common. The AMR rate was high for the following strains: cefotaxime-resistant Klebsiella pneumoniae, 77.4%; cefotaxime-resistant E. coli, 70.6%; imipenem-resistant Acinetobacter baumannii, 90.3%; imipenem-resistant P. aeruginosa, 49.3%; oxacillin-resistant S. aureus, 81.1%, penicillin-resistant Enterococcus faecalis, 44.8%, and vancomycin-resistant Enterococcus faecium, 53.5%. AMR rate change varied by bacterial species and antimicrobial drug.CONCLUSION: AMR rates of major pathogens from nursing hospitals were higher than those from general hospitals with the exception of imipenem-resistant A. baumannii. Continuous monitoring and infection control strategies are needed.
Acinetobacter baumannii ; Enterococcus faecalis ; Enterococcus faecium ; Escherichia coli ; Gram-Positive Bacteria ; Hospitals, General ; Infection Control ; Klebsiella pneumoniae ; Nursing ; Pseudomonas aeruginosa ; Public Health ; Staphylococcus aureus

OBJECTIVE: This work aims to uncover the promoting effect of 17% ethylenediaminetetraacetic acid (EDTA) irrigation on the dentin adhesion of Enterococcus faecalis (E. faecalis). METHODS: Forty-eight half split samples and twelve dentin slices were randomly divided into three experimental groups and one control group. The experimental groups and the control group were soaked with EDTA in different time lengths and with normal saline, respectively. E. faecalis was inoculated, and its dentin adhesion was measured via scanning electron microscopy, confocal laser scanning microscopy (CLSM), colony forming unit counts, and histological Gram staining. RESULTS: According to histological Gram staining, the depth showed no statistically significant differences between 1 min group and the control group, 1 min group and 3 min groups (P>0.05). E. faecalis intruded in the dentine tubules (measured by CLSM), and the thickness of the biofilm on the dentin surface and the colony numbers of experimental groups were greater than those of the control group (P<0.05). The differences between the three experimental groups were statistically signi-ficant (P<0.05). CONCLUSIONS EDTA (17%) irrigation can promote E. faecalis adhesion to dentin. This adhesion would in turn prolong EDTA treatment time.
Biofilms ; Dentin ; Edetic Acid ; Enterococcus faecalis ; Microscopy, Confocal ; Root Canal Irrigants ; Sodium Hypochlorite

BACKGROUND: Factors affecting oral function include tooth number, oral muscle strength, and oral diseases. This study aimed to investigate the relationship among oral environment, muscle, and microbiology. METHODS: Fifty-six elderly individuals in a day care center were included in the study. The survey regarding tongue and lip muscle strength and oral microorganisms was conducted from November to December 2018. RESULTS: Tongue and lip muscle strength were greater in men than women (p>0.05). Tongue muscle strength was greater in the ≤80-year-old group (34.94±9.85) than the ≥90-year-old group (25.57±7.54) (p<0.05). Tongue muscle strength and lip muscle strength were greater in the ≥15 functional teeth group (34.08±9.31 and 9.25±1.63, respectively) than in the <15 functional teeth group (28.08±7.53 and 7.76±1.51, respectively) (p<0.05). Age was significantly correlated with functional tooth number, denture use, and tongue muscle strength. The number of functional teeth was positively correlated with tongue muscle strength, lip muscle strength, and oral microorganisms. Denture use was negatively correlated with tongue and lip muscle strength. Tongue muscle strength was significantly correlated with lip muscle strength. The number of Eubacterium nodatum was higher in men than women. The number of Parvimonas micra and Enterococcus faecalis was higher in the groups with ≥15 functional teeth, denture use, and greater tongue and lip muscle strength. The number of Lactobacillus casei was higher in the group that uses dentures and with greater tongue strength. CONCLUSION: Oral microbiology is more important in oral environment and management than oral muscle function. The correlation between oral muscle and oral microorganism requires further study. Therefore, oral care training should be conducted to improve the oral care practice of elderly individuals, maintain oral health through oral care, and prevent the decrease in saliva secretion by aging.
Aged ; Aging ; Day Care, Medical ; Dentures ; Enterococcus faecalis ; Eubacterium ; Female ; Humans ; Lactobacillus casei ; Lip ; Male ; Muscle Strength ; Oral Health ; Oral Hygiene ; Saliva ; Tongue ; Tooth

Enterococcus faecalis is a major causative agent of endodontic treatment failure. The purpose of this study was to investigate bactericidal effects of ethanol extract of Garcinia mangostana L. (mangosteen extract) on five strains of E. faecalis that were isolated from human oral cavities. The bactericidal effects of mangosteen extract were assessed by measurement of minimum bactericidal concentration (MBC) value. The cytotoxicity of mangosteen extract on immortalized human gingival fibroblasts, hTERT-hNOF, was determined based on cell counting method. The data revealed the MBC value of mangosteen extract against the E. faecalis strains was 4 µg/ml. Additionally, the cell viability of mangosteen extract on hTERT-hNOF was 83.7–89.1% at the 1 to 16 µg/ml. These findings indicated that mangosteen extract could be used as a root canal cleaner during management of endodontic treatment failure caused by E. faecalis.
Cell Count ; Cell Survival ; Dental Pulp Cavity ; Enterococcus faecalis ; Enterococcus ; Ethanol ; Fibroblasts ; Garcinia mangostana ; Garcinia ; Humans ; Methods ; Mouth ; Treatment Failure