[Antimicrobial effect of Citrus aurantifolia extract on Enterococcus faecalis within the dentinal tubules in the presence of smear layer]

Instrumentation of the root canals results in formation of smear layer which covers the dentinal tubules. In infected teeth, it is ideal to achieve a material that has the ability to remove the smear layer besides antimicrobial activity. Therefore, this study was designed to evaluate the antimicrobial effect of Citrus aurantifolia extracts [lime juice and rind extract] on Enterococcus faecalis within dentinal tubules in the presence of smear layer. One-hundred and forty dentin tubes were prepared from bovine incisors. After removal the smear layer, the specimens were infected with Enterococcus faecalis. Then, the smear layer was reformed. Test solutions were used as the irrigants in study groups as follows: group 1: 5.25% NaOCl; group 2: 17% EDTA; group 3: NaOCl+EDTA; group 4: Lime juice; group 5: ethanolic rind extract of C.aurantifolia; group 6: 96% ethanol. Dentin chips were collected from inner and outer layers of dentinal walls and optical density was measured. The data were analyzed using one-way ANOVA and Tamphane tests. In outer layer of dentin, the efficacy of rind extract was less than that of NaOCl+EDTA [P<0.05]. Also Lime juice was less effective than EDTA, NaOCl and NaOCl+EDTA [P<0.05]. In inner layer of dentin, Lime juice was significantly less effective than NaOCl and NaOCl+EDTA [P<0.05]. The efficacy of rind extract was less than that of NaOCl + EDTA [P<0.05]. In the presence of smear layer, the antimicrobial activity of Lime juice was less than that of NaOCl but the efficacy of rind extract was similar to that of NaOCl

In vitro comparison of the antimicrobial effect of calcium hydroxide mixed with different vehicles on infected root canals

The main purpose of root canal treatment is to eliminate microorganisms and their by-products. The use of antimicrobial agents besides mechanical preparation ins necessary to achieve this goal. On the other hand, calcium hydroxide is ineffective in Killing some resistant microorganisms. The aim of this in vitro study was to compare the effectiveness of calcium hydroxide mixed with different vehicles [Distilled water, Sodium hypochlorite or Chlorhexidine] in disinfecting the root canal and dentin of the infected teeth. After root canal preparation of 130 single rooted teeth, they were sterilized and randomly divided into three experimental [n=40 in each grou] and two control groups. Then, the specimens were experimentally infected with E. faecalis and C. albicans during a period of 21 days. The infected specimens were exposed to the pastes of calcium hydroxide mixed with distilled water solution, CHX or NaOCl. Antimicrobial assessment was performed at 24h, 48h, 1 week and 2 week [n=10 in each time interval]. Microbial samples were obtained from the root canals before and after the experiment. Also, the dentin samples were obtained for evaluating dentin disinfection. The data were analyzed, using Two-way ANOVA test. This study showed that there was no significant difference between the three intracanal medicaments and also between the four periods of time [p>0.05]. However, the mixture of calcium hydroxide/distilled water did not completely eradicate E. faecalis from dentinal tubules at any period of time. According to the results of this study, calcium hydroxide mixed with CHX or NaOCl is better than calcium hydroxide mixed with distilled water for dentin disinfection in cases of persistent intracanal infection

Risk factors in neonatal anaerobic infections

Anaerobic bacteria are well known causes of sepsis in adults but there are few studies regarding their role in neonatal sepsis. In an attempt to define the incidence of neonatal anaerobic infections a prospective study was performed during one year period. A total number of 400 neonates under sepsis study were entered this investigation. Anaerobic as well as aerobic cultures were sent. The patients were subjected to comparison in two groups: anaerobic culture positive and anaerobic culture negative and this comparison were analyzed statistically. There were 7 neonates with positive anaerobic culture and 35 neonates with positive aerobic culture. A significant statistical relationship was found between anaerobic infections and abdominal distention and pneumonia. It is recommended for those neonates with abdominal distention and pneumonia refractory to antibiotic treatment to be started on antibiotics with anaerobic coverage

Prevalence of anaerobic and aerobic bacteria in early onset neonatal sepsis

To determine prospectively the prevalence of anaerobic and aerobic infection in early onset [during 72 hours of age] neonatal sepsis, in Tehran Vali-e-Asr Hospital. Among all the live birth, neonates suspecting of having septicemia were investigated for isolation of microorganisms. Culture bottle containing enriched tryptic soy broth was used for standard blood culture system to detect aerobes and an ANAEROBIC/F bottle was inoculated using BACTEC 9120 continuous monitoring blood culture system to determine the growth of anaerobic bacteria. Among 1724 live births, 402 consecutive neonates suspecting of having septicemia were investigated for isolation of micro organism. A total of 27 episodes of early onset neonatal sepsis occurred with an incidence of 15.66 [11.6 aerobe + 4.0 anaerobe] per 1000 live births. Aerobic bacteria were the major etiological agents, accounting for 20 cases. 7 [26%] cases had positive blood cultures with anaerobic bacteria. Propionibacterium and Peptostreptococccus [amongst anaerobic] and coagulase-negative staphylococci and staphylococcus aureus [amongst aerobic] were the most commonly isolated organisms. Comparison of clinical findings and demographic characteristics between aerobic and anaerobic infection did not have a significant statistical difference. Our impression is that while anaerobic bacteremia in the newborn infants can occasionally cause severe morbidity and mortality, majority of cases experience a self limited illness with transient bacteremia

[Evaluation of inactivation of intracanal antiseptics by dentin, demineralized dentin, dentin matrix and mineral component of dentin]

Many studies have shown that microorganisms are the main cause of pulpal diseases and the main purpose of root canal therapy is their elimination from the root canal system. Antiseptic agents are used to reduce bacteria but their antibacterial activities differ from in vivo to in vitro studies and might be inactivated by dentin and its components in root canal space. This study was designed to investigate the effect of dentin on antibacterial activity of different antimicrobial agents. In this experimental study, two antibacterial agents [sodium hypochlorite and chlorhexidine] with different concentrations were used in four experimental groups: Group 1: dentin, Group 2: demineralized dentin with EDTA, Group 3: dentin matrix and Group 4: dentin mineral component. The species used in this study was Entrococcus faecalis. Different concentration of agents were added to mixture of each experimental group and bacteria. At the baseline and after one and 24 hours, samples were collected and cultured. After incubation period, colonies were counted. Data were analyzed by Tukey test with p<0.05 as the limit of significance. 2% and 0.2% chlorhexidine, and 5% sodium hypochlorite solutions at the three studied times eliminated Entrococcus faecalis completely. 1% sodium hypochlorite eliminated all bacteria in 1h and 24 hs. Statistical analysis showed significant differences between experimental and control groups [P<0.05]. Sodium 1% hypochlorite at time 0, could reduce bacteria significantly [P<0.05] but didn't eliminate them completely. Inactivation of intracanal antiseptics was not observed in this study. As elimination of bacteria occurred, application of these antibacterial agents are recommended in endodontic treatment. Further investigations on other antibacterial agents, other concentrations and shorter time intervals are recommended

Determination of antimicrobial resistance pattern of staphylococcus aureus isolated from clinical specimens

Staphylococcus aureus is an important cause of nosocomial and community-acquired infections. The emergence of antibiotic resistance, especially in methicillin-resistant SA [MRSA] strains, has caused difficulties in treatment of such infections. The determination of antibiotic resistance patterns, particularly domestic patterns of Iran, is essential for appropriate treatment of MRSA infections and proper infection control measures in our country. The antibiotic resistance of 338 SA isolates from various clinical specimens was determined by disk agar diffusion [DAD], minimum inhibitory concentration [MIC] and polymerase chain reaction [PCR] methods. Using the DAD method, 47% [160/338] of the SA isolates were resistant to oxacillin, and only 6% [20/338] were resistant to vancomycin. By PCR, 48% [162/338] of the isolates had the mecA gene. The MIC of oxacillin in 93% of isolates was higher than 256 micro g/mL. The MRSA isolates, showed a high resistant to gentamicin [40.5%], erythromycin [40%], and ciprofloxacin [38%]. However, only a few of the SA isolates showed a high resistance to vancomycin [5%] or erythromycin [3.5%]. The results of this study can provide guidance for physicians toward a more appropriate treatment of SA infections in Iran, thereby preventing the emergence of further antibiotic resistance among SA. Our results also revealed the need for further investigations using a higher number of specimens representing a wider variety of locations to determine the antibiotic resistance patterns in our state more precisely

Bacterial contamination of four commonly used dental materials

Bacterial contamination of dental materials and devices used in dental clinics and laboratories can lead to infectious diseases in patients, dentists and dental care providers. The aim of this study was to examine bacterial contamination of four dental materials. In this analytic-descriptive study, flour of pumice, zinc oxide powder, prophylaxis paste and wooden wedges of available commercial brands were tested. To assure an examiner-blind study, the samples were coded in the microbiology laboratory. In sterile conditions, the samples were inoculated in tryptycase soy broth and sodium tioglycolate for aerobic and anaerobic bacterial growth, respectively. The media was then incubated in 35 degrees centigrade and checked daily. Flour of pumice showed contamination to coagulase-negative Staphylococci, Enterococcus faecallis, bacillus and diphteroid. Some of the prophylaxis pastes were contaminated with micrococcus roseous, coagulase-negative staphylococci and diphteroid. One brand of wooden wedges demonstrated contamination to staphylococcus, diphteroid and bacilli. Zinc oxide powders were not contaminated. None of the samples showed contamination to anaerobic bacteria. Some of the investigated materials showed bacterial contamination, but the identified bacteria are not pathogen in normal situations

Study of antibiotics resistance in pediatric acute bacterial meningitis with E test method

Appropriate treatment of bacterial meningitis especially in children is a important problem due to multiple drug resistance. The determination MIC of conventional antibiotics for bacterial meningitis with quantitative E. test is exactly practical and essential. We studied MIC of conventional antibiotics in pediatric acute bacterial meningitis older than two months, center children hospital, 1382-1384. In this prospective and cross sectional process research we measured MIC of antibiotics in 30 positive bacterial culture in CSF or blood with quantitative E. test and compared with qualitative disk diffusion test. Antibiotic resistance of 10 Haemophilus influenzae type b patient was: ampicillin resistance in 90%, co- Amoxiclave R. in 10%, chlorampheicol R. in 40%, third gerenation cephlosporins R.[ceftriaxone and cefotaxime] in 0% and cotrimoxazole R. in 100% and antibiotic resistance of 20 streptococcous pneumoniae patient was: penicillin R. in 35%, chloramphenical R. in 10%, third generation cephalosporins R. in 5%,rifampin R. in 10% and cotrimoxazole R. in 60% .In comparison of two methods E-Test and Disk Diffusion we found insignificant difference. Antibiotic Resistance of our study is compatible with other studies. Therefore it seems that composition of ampicillin and chloramphenicol as empiric therapy for bacterial meningitis for many years ago,aren't appropriate today and third generation cephalosporins alone or with vancomycin is a suitable therapy

Detection of haemophilus influenzae type b in cerebrospinal fluid of suspected children with meningitis byPCR

A polymerase chain reaction [PCR] assay with primers from "hpd" gene was compared with culture for the detection of Haemophilus influenza type b [Hib] in CSF samples from children suspected of meningitis.300 cerebrospinal fluid [CSF] samples from suspected meningitis cases were studied by culture [Leventhal and Chocolate Agar] and PCR.The latter method could detect Hib in all 5 culture positive and in 2 of 295 culture negative cases, showing sensitivity, specificity, and an accuracy index of 100%, 99% and 99%, respectively. The PCR result was available within a day.This study has shown that PCR is a rapid, sensitive, and specific diagnostic test for Hib from CSF samples. Furthermore, to maximize management of meningitis cases to reduce the morbidity, mortality, and complications of invasive Hib infection a combination of culture and PCR is necessary for the detection of Hib infection. The incidence of Hib meningitis among children in Children's Medical Center in Tehran based on culture and PCR results were 2.4% and 1.7% respectively. Based on culture results, Hib causes 15.6% of all cases of bacterial meningitis in children

Evaluation of reduction in intracanal bacteria by three instrumentation technique: K-type manual system file, rotary race and profile system

Root canal cleaning and elimination of the source of infection are the most important basis and the main requirements for successful root treatment since the main cause of failure in root treatment is the permeation of bacteria or their products into the periapical tissues. Nowadays, the newly designed and prcsented instruments for canal instrumentation can improve root treatment. The aim of this study was to compare the decrease in the number of intracanal Enterococcus-faecalis [Ef] among three mechanical instrumentation methods: manual [K-type] and rotary [Race, Profile]. In this experimental study, 30 single rooted teeth were selected. Three cases were considered as negative and three cases as posetive controls and 24 remainder cases were divided into three experimental groups. All root canals were inoculated by Ef and samples were taken from all canals to prepare microbial cultures. The three instrumentation procedures were: - Crown- down technique with K-type manual system file - Crown- down technique with Profile rotary system - Crown- down technique wiht Race rotary system After instrumentation, microbial cultures were taken from root canals and the reduction rate of bacteria were evaluated and compared using one way ANOVA test with P<0.05 as the limit of significance. There was no significant difference among the three instrumentation procedures regarding bacterial elimination. According to the finding of this study, K-type manual file, Profile and Race rotary systems, all can be used in canal instrumentaion. However, since manual files are more accessible and require less equipment compared with rotary systems, and since the ability of all of these methods is identical regarding bacterial elimination, manual files can be used in straight canal instead of rotary systems

[Evaluation of bacterial leakage of four root-end filling materials: Gray Pro Root MTA, white Pro Root MTA, Root MTA and Portland cement [type I]]

Today several materials have been used for root- end filling in endodontic surgery. Optimal properties of Pro Root MTA in in-vitro and in-vivo studies has been proven. On the other hand, based on some studies, Root MTA [Iranian Pro Root MTA] and Portland cement are similar to Pro Root MTA in physical and biologic properties. The aim of this study was to evaluate bacterial leakage [amount and mean leakage time] of four root- end filling materials. In this experimental in-vitro study, seventy six extracted single- rooted human teeth were randomly divided into six groups for root-end filling with gray Pro Root MTA, white Pro Root MTA, Root MTA [Iranian Pro Root MTA], Portland Cement [type I] and positive and negative control groups. Root canals were instrumented using the step- back technique. Root- end filling materials were placed in 3mm ultra sonic retro preparations. Samples and microleakage model system were sterilized in autoclave. The apical 3-4 mm of the roots were immersed in phenol red with 3% lactose broth culture medium. The coronal access of each specimen was inoculated every 24h with a suspension of Streptococcus sanguis [ATCC 10556]. Culture media were observed every 24h for colour change indicating bacterial contamination for 60 days. Statistical analysis was performed using log- rank test with P<0.05 as the limit of significance. At the end of study 50%, 56.25%, 56.25% and 50% of specimens filled with Gray Pro Root MTA, White Pro Root MTA. Root MTA and Portland Cement [type I] had evidence of leakage respectively. The mean leakage time was 37.19 +/- 6.29, 36.44 +/- 5.81, 37.69 +/- 5.97 and 34.81 +/- 6.67 days respectively. Statistical analysis of data showed no significant difference among the leakage [amount and mean leakage time] of the four tested root- end filling materials [P=0.9958]. Based on the results of this study, there were no significant differences in leakage among the four tested groups at 60 days. The results suggest that Root MTA and Portland Cement can be used as less expensive root filling materials

[ survey on the disinfectant effects of HcloNa solution of different concentrations on Gutta Percha cones contaminated by microbial species]

Background and aim: nowadays, Gutta Percha cones are widely used as a canal filling material. Since these materials can not be sterilized through common methods of dry or wet heat, quick sterilization of Gutta Percha cones, while and prior to manipulation, is a necessity as a substantial factor in a successful endodontic treatment

Materials and Methods: the purpose of this study was to assess the disinfectant effect of HcIoNa solution of various concentrations on Gutta percha cones artificially contaminated by Enterococcus fecalis and Bacillus subtilis spore

Results: in this study, 160 Gutta percha cones No.80 of Ariadent brand were used. Gutta percha cones were initially immersed in microbial solutions for thirty minutes. Having been transferred to vessels containing sterile filter paper, they were dried for ten minutes in room temperature. caries were then transferred to plastic containers each separately in a sterile condition and immersed in HcloNa solution of 0.5%, 1%, 2% and 5.25% concentrations for 1, 3 and 5 minutes. All cones were then transferred into tubes containing serum physiology and thiosulfate [0.6%]. This solution was mixed for twenty seconds by Vortex mixer and samples of undiluted solution [5.25%] and 0.5%, 1% and 2% diluted ones were cultured in tryptic agar environment. The number of colonies were then counted and reported in CFUML

Conclusion: considering that all HcloNa solutions of different concentrations showed anti-bacterial and anti-spore properties, Gutta percha cones sterilization by HcloNa [0.5%] solution for one minutes, is recommended