Antibacterial and Anti-biofilm Activity of AH Plus with Chlorhexidine and Cetrimide

Introduction

The use of root canal filling materials with antibacterial activity can be considered beneficial to reduce the remaining microorganisms in the root canal system, where Enterococcus faecalis is often found, and prevent recurrent infection. The aim of this study was to evaluate the antimicrobial activity and capacity for inhibiting E. faecalis biofilm formation of AH Plus, alone and mixed with chlorhexidine (CHX), cetrimide (CTR), and combinations of the two.

Methods

AH Plus alone and mixed with 1% and 2% CHX, 0.1%–0.5% CTR, and combinations of both were tested to assess antimicrobial activity by a modified direct contact test and determine inhibition of E. faecalis biofilm formation at 24 hours. The results were expressed as log₁₀ viable counts. Eradication and inhibition of biofilm formation were understood as no bacterial growth or log₁₀ reduction = 5 with respect to the control (AH Plus alone).

Results

AH Plus + CHX showed a low antimicrobial activity with respect to the control (at 2%, log₁₀ reduction = 1.30). None of the tested concentrations achieved eradication or inhibition of biofilm. AH Plus + CTR showed a direct relationship of concentration-antimicrobial effect, reaching a log₁₀ reduction of 2.92 at 0.5% and inhibition of biofilm formation at 0.2%. With the combination CHX + CTR, lower concentrations were needed for the same effect, and eradication and inhibition of biofilm were achieved.

Conclusions

The addition of CHX, CTR, or some combination of both to AH Plus confers it with bactericidal and anti-biofilm activity against E. faecalis.     

Effect of Long-term Exposure to Endodontic Disinfecting Solutions on Young and Old Enterococcus faecalis Biofilms in Dentin Canals

Introduction

The purpose of this study was to evaluate the antimicrobial activity on Enterococcus faecalis biofilms in dentin canals of short-term and long-term exposure to different endodontic disinfecting solutions by using a dentin infection model and confocal laser scanning microscopy.

Methods

Dentinal tubules in semi-cylindrical dentin blocks were filled with E. faecalis by centrifugation and incubated to form 1-day-old and 3-week-old biofilms. The young and mature biofilms in dentin were subjected to sterile water, 2% chlorhexidine, 2% sodium hypochlorite (NaOCl), and 6% NaOCl for 3, 10, and 30 minutes. After treatments, the proportion of bacteria killed by the disinfectants was analyzed by confocal laser scanning microscopy by using LIVE/DEAD bacterial viability stain.

Results

The proportion of killed bacteria was lower after 3 minutes than after 10 and 30 minutes of exposure to the disinfecting agents (P < .05). The killing of bacteria in the E. faecalis biofilms was fastest during the first 3 minutes and slowed down greatly after 10 minutes. Six percent NaOCl was the most effective antibacterial solution against both the 1-day-old and 3-week-old biofilms (P < .05). No significant difference in bacterial killing was detected between 2% chlorhexidine and 2% NaOCl (P > .05). Significantly more cells were killed in young biofilms than in old biofilms in all groups (P < .05).

Conclusions

The killing of bacteria in infected dentin by disinfecting solutions is time-dependent. However, little additional killing is obtained after the first 10 minutes of exposure.     

Antibiofilm Effects of Endodontic Sealers Containing Quaternary Ammonium Polyethylenimine Nanoparticles

Introduction

This study evaluated the antibiofilm effects of 2 endodontic sealers incorporated with quaternary ammonium polyethylenimine (QPEI) nanoparticles at a 2% concentration (w/w).

Methods

The materials tested were AH Plus and Pulp Canal Sealer EWT (PCS) in the commercial unmodified form or containing 2% QPEI. Antibiofilm assays were conducted by using direct-contact and membrane-restricted tests for evaluation of bacterial viability in biofilms grown onto membranes or paper disks and the crystal violet microtiter-plate assay to evaluate the effects of sealer extracts on the biofilm biomass. Two Enterococcus faecalis strains (ATCC and an endodontic isolate) were used.

Results

Direct contact and membrane-restricted antibiofilm tests revealed that PCS 2% was the only material to promote total killing of E. faecalis ATCC biofilms. All the materials significantly reduced bacterial counts in E. faecalis ATCC biofilms when compared with the positive control in both tests (P < .05). In the direct test against E. faecalis RW35, PCS 2% was significantly more effective than the other materials and was the only one that showed significantly lower counts than the positive control (P < .05). In the crystal violet assay, only AH Plus 2% presented optical density readings significantly lower than the positive control of the ATCC strain (P < .05). No other significant effects on the biofilm biomass of the 2 E. faecalis strains were observed for any of the sealers tested (P > .05).

Conclusions

Addition of QPEI nanoparticles improved the killing ability of PCS against biofilms of both E. faecalis strains and the effects of AH Plus on the biomass of biofilms from the ATCC strain.     

双歧杆菌四联活菌片联合用药治疗小儿非感染性腹泻的效果及对血清IL-6、IL-17表达的影响

目的：探讨双歧杆菌四联活菌片治疗小儿非感染性腹泻的临床效果及对血清IL-6、IL-17表达的影响。方法选取2013年2月~2014年6月本院收治的120例非感染性腹泻小儿,将其随机分为观察组和对照组,各60例,对照组采用常规方法治疗,观察组在对照组基础上采用双歧杆菌四联活菌片治疗,比较两组的总有效率、腹泻停止时间、住院时间和IL-6、IL-17水平。结果观察组总有效率为96.67%,高于对照组的85.00%,差异有统计学意义（P<0.05）;观察组腹泻停止时间和住院时间均短于对照组,差异有统计学意义（P<0.05）;治疗72 h后,观察组IL-6、IL-17水平显著低于对照组（P<0.05）。结论双歧杆菌四联活菌片治疗小儿非感染性腹泻可缩短患儿腹泻停止时间及住院时间,降低IL-6、IL-17水平,具有显著的临床疗效,值得推广应用。     

腹腔感染病原菌及其耐药性

目的了解腹腔感染病原菌构成及其耐药性,为临床腹腔感染的治疗提供参考依据。方法对某院2011年1月—2013年12月住院患者送检的腹腔感染标本进行菌种鉴定及药物敏感性检测,并将数据输入WHONET5.6软件进行统计分析。结果 15 946份腹腔感染标本分离非重复病原菌810株,培养阳性率5.08%;革兰阴性杆菌485株(59.88%),革兰阳性菌275株(33.95%),真菌50株(6.17%);居前5位的病原菌分别为大肠埃希菌(24.20%)、屎肠球菌(15.06%)、鲍曼不动杆菌(8.89%)、肺炎克雷伯菌(7.66%)和凝固酶阴性葡萄球菌(6.91%)。产超广谱β-内酰胺酶(ESBLs)大肠埃希菌和肺炎克雷伯菌检出率分别为59.18%和32.79%,各种肠杆菌科细菌对亚胺培南仍高度敏感,但对碳青霉烯类耐药的菌株占4.08%~6.67%;多重耐药鲍曼不动杆菌占52.11%(37/71),耐甲氧西林金黄色葡萄球菌(MRSA)占53.57%(15/28),耐甲氧西林凝固酶阴性葡萄球菌(MRCNS)占71.43%(40/56),耐万古霉素屎肠球菌(VRE)占8.26%。结论该院腹腔感染病原菌主要是以大肠埃希菌为代表的革兰阴性菌,屎肠球菌是最常见革兰阳性致病菌,细菌耐药形势严峻。     

VanC型肠球菌与屎肠球菌对常用抗菌药的耐药状况研究

目的：比较VanC型肠球菌及屎肠球菌对常用抗菌药物的敏感性。方法针对56株VanC型肠球菌及299株屎肠球菌,用琼脂二倍稀释法进行药物敏感性分析;检测高水平耐万古霉素屎肠球菌的万古霉素耐药基因型。结果VanC型肠球菌万古霉素最低抑菌浓度（ MIC）众数为4 mg? L－1,未发现对氨苄西林、万古霉素、替考拉宁及利奈唑胺耐药的VanC型肠球菌。屎肠球菌对氨苄西林、左氧氟沙星、红霉素及利福平的耐药率均达85％以上;对万古霉素和替考拉宁的耐药率分别为1．7％和0．7％;未发现对利奈唑胺和替加环素耐药的屎肠球菌。屎肠球菌万古霉素MIC众数为0．5 mg? L－1。5株万古霉素屎肠球菌万古霉素耐药基因均为vanA型。结论屎肠球菌对万古霉素尚保持较高敏感性,万古霉素对VanC型肠球菌最低抑菌浓度较屎肠球菌高。     

Antimicrobial susceptibility among E. faecalis and E. faecium from France,Germany, Italy,Spain and the UK (T.E.S.T. Surveillance Study, 2004-2009)

Abstract

We report on antimicrobial activity against E. faecalis and E. faecium collected in France, Germany, Italy, Spain, and the UK between 2004 and 2009 as part of the Tigecycline Evaluation and Surveillance Trial (UK in vitro data not included due to low isolate numbers). Overall, 1·1% (n?=?23/2068) of E. faecalis and 11·5% (n?=?103/893) of E. faecium were vancomycin-resistant. High levels of minocycline-resistant E. faecalis were reported in Germany, Spain, France, and Italy (40·2–44·2%); levofloxacin resistance was high in Germany, Italy, and Spain (31·1–41·6%). Minocycline non-susceptibility increased significantly among E. faecalis in Spain and Italy (P<0·001). No tigecycline-resistant E. faecalis were reported. Among E. faecium, resistance ranged from 72·9% (France) to 93·3% (Germany) for ampicillin, from 56·1% (France) to 90·2% (Germany) for levofloxacin, and from 75·3% (Italy) to 94·7% (Germany) for penicillin. Levofloxacin non-susceptibility increased significantly among E. faecium in France and Spain (P<0·001). The lowest rates of antimicrobial resistance among E. faecium were reported for tigecycline (2/893; 0·2%) and linezolid (3/893; 0·3%).     

Prevalence,outcome and risk factor associated with vancomycin-resistant Enterococcus faecalis and Enterococcus faecium at a Tertiary Care Hospital in Northern India

Purpose: To determine the prevalence, genotype, risk factors and mortality in patients having vancomycin-resistant Enterococcus faecalis (VR E. faecalis) and Enterococcus faecium (VR E. faecium) infection or colonisation. Materials and Methods: A total of 1488 clinical isolates of E. faecalis and E. faecium were tested for vancomycin resistance by phenotypic (disk diffusion, E-test and broth micro-dilution test) and genotypic polymerase chain reaction methods. Records of all 1488 patients who had E. faecalis or E. faecium infection or colonisation were reviewed for the identification of host, hospital and medication related risk factors associated with VR E. faecalis and VR E. faecium. Results: Of 1488 isolates, 118 (7.9%) were vancomycin-resistant and their distributions were as follows: E. faecalis =72 (61%) and E. faecium =46 (39%). All 118 vancomycin-resistant isolates were vanA genotype (minimum inhibitory concentration [MIC] to vancomycin ≥64 μg/ml and MIC to teicoplanin ≥32 μg/ml) and none of the isolates was vanB genotype. Multivariate logistic regression analysis identified ventilator support and hospital stay for ≥48 h as independent risk factors associated with VR E. faecalis and VR E. faecium infection or colonisation. Hospital stay ≥48 h was the only independent risk factor for mortality in patients infected with vancomycin-resistant enterococci. Conclusions: Strategies to limit the nosocomial infection especially in patients on ventilator support can reduce VRE incidence and related mortality.