Real-time polymerase chain reaction quantification of specific butyrate-producing bacteria, Desulfovibrio and Enterococcus faecalis in the feces of patients with colorectal cancer

Background and Aim:  Bacterial metabolites produced in the bowel are potentially related to the genesis of colorectal cancer. Butyrate is protective against cancer, whereas hydrogen sulfide and oxygen free radicals can be toxic to the epithelium. The present study was designed to quantitate Eubacterium rectale , Faecalibacterium prausnitzii (both butyrate-producing bacteria), Desulfovibrio (sulfate-reducing bacteria), and Enterococcus faecalis (that produces extracellular superoxide) in the feces of patients with colorectal cancer.
Methods:  DNA was extracted from feces of 20 patients with colorectal cancer, nine patients with upper gastrointestinal cancer and 17 healthy volunteers. Real-time polymerase chain reaction using primers aimed at 16S rDNA was used to quantitate the above bacterial species or genus, and this was expressed relative to amplification of universal sequences conserved among all bacteria.
Results:  Levels of E. rectale and F. prausnitzii were decreased approximately fourfold ( P  = 0.0088 and 0.0028, respectively) in colorectal cancer patients compared to healthy control volunteers. Levels of Desulfovibrio were not significantly different between the three groups. E. faecalis populations were significantly higher in colorectal cancer patients compared to healthy volunteers ( P  = 0.0294).
Conclusions:  Butyrate producers were decreased and E. faecalis increased in the feces of colon cancer patients. These shifts in the colonic bacterial population could potentially lead to epithelial cell damage and increased turnover and may be a factor leading to colon cancer.     

Antiviral activity of enterocin CRL35 against herpesviruses

Enterocin CRL35 is an antibacterial polypeptide of 3.5×10³ Da produced by Enterococcus faecium CRL35. A series of experiments are described that show the enterocin also had antiviral activity against thymidine-kinase positive (tk⁺) and deficient (tk⁻) strains of herpes simplex (HSV) type 1 and 2 in Vero and BHK-21 cells. This activity was observed at 100 μg/ml, 15-fold lower than the cytotoxic concentration. In both cell lines there was a 2 log inhibition of infectivity. The compound inhibited viral multiplication in a dose-dependent manner and had no virucidal effect. Enterocin CRL35 also inhibited the virion-associated host shutoff in infected Vero cells showing that intracellular viral multiplication was affected.     

777株临床分离肠球菌的分布及耐药性分析

目的了解本院临床肠球菌的菌群分布及耐药情况。方法采用回顾性调查分析方法对我院分离自各类临床标本的777株肠球菌进行统计,并对抗菌药敏试验结果进行分析。结果肠球菌菌株来源以尿液(30.5%)、胆汁(25.5%)、分泌物(17.8%)为主;2007～2010年分离的肠球菌对抗生素的耐药率有逐年增高趋势(P<0.05);屎肠球菌对多种抗生素的耐药率明显高于粪肠球菌,且在分离的肠球菌构成比有增高趋势。结论屎肠球菌在临床分离的肠球菌中越来越常见,肠球菌的多重耐药严重。     

Detection of antibiotic resistant E. coli and Enterococcus spp. in stool of healthy growing children in Portugal

From stool specimens of 118 healthy children's (1–14 years) in Portugal 92 E. coli and 101 Enterococcu s spp. strains have been isolated. Almost half (40.2%) of the E. coli isolates were resistant to ampicillin, 25.0% were resistant to tetracycline and 26.1% were resistant to streptomycin. Resistance genes detected by specific PCR included bla_TEM and/or bla_SHV and/or bla_CTX‐M (33 of 37 ampicillin and/or cefotaxime resistant isolates), tet (A) and/or tet (B) (16 of 23 tetracycline‐resistant isolates), aad A (19 of 24 streptomycin‐resistant isolates), cml A (in the two chloramphenicol‐resistant isolates), aac (3)‐II with/without aac (3)‐IV (in the four gentamicin‐resistant isolates), sul 1 and/or sul 2 and/or sul 3 (in all trimethoprim/sulfamethoxazole resistant isolates). The majority of the resistant E. coli isolates (69.1%) belonged to phylogenetic group B2. Of the enterococci isolates E. faecium (n = 53), E. faecalis (n = 41), E. hirae (n = 4) and E. durans (n = 3) more than one‐fourth (28.7%) of the isolates were resistant to tetracycline; 21.8% were resistant to erythromycin and 8.9% were resistant to kanamycin. Resistance genes detected by PCR in enterococci included aph (3)′‐IIIa (in all kanamycin‐resistant isolates), aac (6′) (in all gentamicin‐resistant isolates), tet (M) and/or tet (L) (26 of 29 tetracycline‐resistant isolates), erm (B) (17 of 22 erythromycin‐resistant isolates). This survey showed that faecal bacteria such as E. coli and enterococci of healthy growing children's could be a reservoir of antimicrobial resistance genes. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

A febrile neutropenic patient with Enterococcus gallinarum sepsis treated with daptomycin and gentamicin

Gram-positive pathogens are increasingly implicated in today's changing epidemiology of hospital-acquired infections. Staphylococci, streptococci, and enterococci are among the most frequently identified causes of surgical site, complicated skin-structure, and bloodstream infections. In accordance, the use of antimicrobial agents with gram-positive activity, especially those with activity against resistant organisms, has also increased. We describe a septic, neutropenic patient with bacteremia due to Enterococcus gallinarum. Therapeutic options were restricted due to resistance factors of the organism, limited guidance in the medical literature, and the patient's history and underlying condition. Despite these challenges, the patient was successfully treated with a combination of daptomycin and gentamicin and replacement of her indwelling central line. As antimicrobial stewards and diagnosticians, we must bear in mind that selective pressures exerted by the increasing use of agents with gram-positive activity may result in an increased prevalence of organisms such as E. gallinarum.     

Microbial analysis of endodontic infections in teeth with post-treatment apical periodontitis before and after medication

This study aimed to determine the intraradicular microbiota of previously root canal-treated teeth with apical periodontitis and to investigate the antibacterial effectiveness of different intracanal medicaments. Sixteen patients with post-treatment apical periodontitis were allocated into two groups according to the intracanal medicament used: calcium hydroxide (CH) and 2% chlorhexidine gluconate gel (CHX) group. Total bacterial loads, as well as the amount of Enterococcus faecalis (E. faecalis) were determined before (S1) and after (S2) chemomechanical preparation and finally, after intracanal medication (S3) by means of ddPCR. The unpaired t test was used to compare parametric. S3-total bacteria copy number of the CH group was lower than the CHX group (p < 0.05). There was no statistical difference between the CHX- and the CH groups in terms of E.faecalis copy number (p > 0.05). But in terms of total bacteria, CH is better than CHX. Consequently, CH can be used to optimise the antibacterial efficiency of chemomechanical preparation in previously root canal-treated teeth with apical periodontitis.     

Antimicrobial action of four herbal plants over mixed-species biofilms of Candida albicans with four different microorganisms

This study aimed to evaluate the antimicrobial effect of four herbal plants glycolic extracts over mixed-species biofilm composed of Candida albicans (C. albicans) and another pathogenic bacterium as alternative therapy to be investigated. Four plants extract of Pfaffia paniculata roots; Hamamelis virginiana leaf, Stryphnodendron barbatiman tree bark and Gymnema sylvestre stem and leaves were tested over multi-species biofilm of C. albicans (ATCC 18804) and Streptococcus mutans (ATCC 35688), Staphylococcus aureus (ATCC 6538), Enterococcus faecalis (ATCC 4083) or Pseudomonas aeruginosa (ATCC 15442) for 5 min and 24 h and colony forming units per millilitre was calculated. The data were analysed using Kruskal–Wallis with Dunn's test (p ≤ 0.05). All tested extracts showed antimicrobial action over the mixed-species biofilms after 24 h. Some extracts eliminated totally the biofilms. The glycolic extract of P. paniculata, H. virginiana, S. barbatiman and G. sylvestre are effective over mixed-species biofilms and may be indicated as endodontic irrigant or intracanal medication.     

Bacterial leakage in root canals filled with AH Plus and dentine bonding agents

Objective. The aim of this study was to compare the efficacy of different dentine adhesives in delaying the coronal bacterial leakage of Enterococcus faecalis in filled root canals. Materials and methods. Ninety-five lower incisors of patients >65 years of age were instrumented using the ProTaper® system and were irrigated with 1 mL of 2.5% sodium hypochlorite (NaOCl) alternated with 1 mL 17% EDTA between each file change. Final irrigation was performed with 5 mL of 17% EDTA and then flushed with 5 mL of distilled water. The teeth were randomly divided into five experimental groups (n = 15/group) and one of the following dentine adhesives was applied: (1) AdheSE®; (2) Excite® DSC; (3) Clearfil^? Protect Bond; (4) One Coat 7.0; or (5) Control group without adhesive. After filling the root canals, the samples were mounted on a double chamber device to evaluate the bacterial filtration of E. faecalis during a period of 240 days. The results underwent non-parametric Kaplan-Meier survival analysis and comparisons among groups were done using the Log-Rank test. Results. At 240 days, E. faecalis was detected in samples of all groups in the lower chamber. The highest survival value was obtained by One Coat 7.0, giving statistically significant differences from the other groups, whereas Clearfil^? Protect Bond, AdheSE® and Excite® DSC showed similar behaviours, likewise similar to the Control group. Conclusions. One Coat 7.0 adhesive system provides the longest survival value to delay E. faecalis coronal leakage in filled root canals.     

Assessment of depth of penetration and antibiofilm properties of Boswellia sacra compared with calcium hydroxide intracanal medicament (in vitro study)

Successful endodontic treatment requires advanced materials to eliminate biofilm This study aims to assess the penetration depth and the effectiveness of Boswellia sacra as a novel intracanal medicament compared with calcium hydroxide against Enterococcus faecalis biofilm. 60 single-rooted teeth were decoronated, prepared and sterilised. Fifty teeth were contaminated with a culture of E. faecalis (ATCC 19433) for 21 days. Two teeth were used to confirm the biofilm using scanning electron microscope. For colony-forming unit (CFU), 40 samples were divided into one control group (calcium hydroxide) and the other experimental group (B. sacra). Each group was divided into two subgroups to be tested at 3 and 7 days. The minimum inhibitory concentration (MIC) of B. sacra was determined, and the B. sacra's ethanolic extract medicament was prepared. Eight discs divided into groups similar to CFU were used to evaluate live/dead bacteria using confocal laser scanning microscopy (CLSM). Ten teeth were selected for penetration depth using CLSM. The intracanal medicaments were mixed with 0.1% rhodamine B. were inserted into the root canals 0.2 slices were dissected and viewed under CLSM. The MIC of B. sacra was 1.25 mg/ml. The CFU evaluation proved that B. sacra are more effective than calcium hydroxide in the 3 days groups. However, it was statistically insignificant compared with calcium hydroxide after 7 days. The depth of penetration of B. sacra exceeds that of calcium hydroxide. B. sacra is an effective intracanal medicament.