Significant Decrease In Colony Forming Units Research Articles

Optimizing Dermal Delivery of Linezolid for Treating Skin and Soft Tissue Infections: NLC-Based Gel Formulation Using Taguchi Design

Background: Uncomplicated skin and soft tissue infections account for approximately 200 million visits to ambulatory care settings annually. Linezolid (LNZ) is an oxazolidinone that has proven its effectiveness in combating skin and soft tissue infections caused by gram-positive pathogens. LNZ is administered via oral suspension, tablets, or an intravenous route in most in-stances. However, its extended therapy leads to undesirable side effects like diarrhoea, thrombo-cytopenia, myelosuppression, lactic acidosis, etc. and even life-threatening complications. The dermal administration of LNZ offers an alternative route, ensuring localized and sustained release at the site of infection. This approach may reduce systemic exposure and allow for lower doses compared to oral ingestion, which can decrease the risk of adverse effects. Objective: This research aimed to develop a nanostructured lipid carrier (NLC)-based gel for de-livering LNZ via the dermal route to treat uncomplicated skin and soft tissue infections. Methods: NLC were developed by high-shear homogenisation and sonication method using glyc-eryl trimyristate as a solid lipid and neem oil as a liquid lipid. The Taguchi design was employed to optimize NLCs using surfactant concentration (mg), drug-to-lipid ratio, and sonication time (sec) as independent variables. Their effect on particle size, zeta potential, and entrapment effi-ciency was studied. The optimized nanocarriers were developed into a gel product and evaluated for drug release, permeation, and antibacterial activity. Results: The optimised process parameters to attain outcomes were 2% surfactant, 1:1 drug-to-lipid ratio and 300 seconds of sonication. The resulting NLC had an average size of 191.2 ± 2.76 nm, a zeta potential of -30.7 ± 4.50 mV, and 84.89 ± 2.76% drug entrapment. NLC-based gel dis-played anomalous transport with a 90.16 % drug release. The gel showed a strong antibacterial effect against Staphylococcus aureus with a 7.57 ± 0.12 cm mean zone of inhibition. Ex-vivo skin permeation studies revealed 24.19 ± 0.19 % drug permeation and 64.46 ± 0.58% cutaneous depo-sition. NLC-based gel demonstrated a significant decrease in colony-forming units in infected an-imal models. Conclusion: The ex-vivo investigations demonstrated the presence of LNZ at the infection site, enhancing therapeutic effectiveness. In vitro and in-vivo findings illustrated the substantial anti-bacterial efficacy of LNZ NLC-based gel. The adoption of NLC-based gel exhibits promising po-tential as a carrier for dermal delivery of LNZ.

Comparative Evaluation of Residual Antibacterial Substantivity of Chlorhexidine, MTAD and Chitosan Against Enterococcus Faecalis in Human Root Dentin - An In vitro Study.

Complex anatomy of the root canal system results in incomplete debridement with mechanical instrumentation, leaving some areas or root canal walls untouched. There comes the significance of endodontic irrigants with residual antibacterial substantivity which prolongs the post-antibiotic effect, thereby improving the success and predictability of endodontic treatment. To comparatively evaluate the residual antibacterial substantivity of 2% chlorhexidine, Biopure MTAD and 2% chitosan against Enterococcus faecalis at intervals of 1, 14 and 28 days. Seventy-five therapeutically extracted permanent single rooted mandibular premolars teeth were selected. Dentin blocks of 4 mm thickness were prepared and enlarged to 1.6 mm. The autoclaved blocks were inoculated with 24-hour colonies of pure cultures of E. faecalis for 14 days. After the contamination period, canals of each dentin block were irrigated with 5 ml of sterile saline and dried with sterile paper points. A total of 75 dentin blocks were randomly divided into five groups as follows: Group A (21 specimens): 2% chlorhexidine, Group B (21 specimens): Biopure MTAD, Group C (21 specimens): 2% chitosan, Group D (6 specimens): positive control (infected dentin tubes) and Group E (six specimens): negative control (sterile dentin tubes). Then, the lumens of dentin blocks were irrigated with the respective irrigants for 10 mins and were dried using sterile paper points. The specimens were then incubated at 37°C for 28 days to maintain humidity. At experimental intervals of 1, 14 and 28 days, dentin shavings were removed from the canals of respective groups by circumferential filing with sterile no. 35 Hedstrom files. The powdered dentin samples obtained with each dentin block were observed for colony forming units (CFUs) using a Digital Colony counter and were expressed as CFUs/mL. All the irrigants in the study showed a significant decrease in CFUs from day 1 to day 28 indicating that they have residual antibacterial substantivity against E. faecalis. Group B (Biopure MTAD) showed significantly least mean CFUs compared to Group A (2% CHX) and Group C (2% chitosan) against E. faecalis at B1(day 1), B2(day 14) and B3(day 28). Group A (2% CHX) showed significantly higher mean CFUs than Group C (2% chitosan) at A1(day 1). Group C (2% chitosan) showed significantly higher mean CFUs compared to Group A (2% CHX) at C2(day 14) and C3 (day 28). MTAD showed statistically higher residual antibacterial substantivity against E. faecalis at experimental periods of 1, 14 and 28 days. The residual antibacterial effect of 2% chitosan was better compared to 2% CHX at day 1. The residual antimicrobial substantivity of 2% CHX was higher compared to 2% chitosan at intervals of 14 and 28 days.

Bacterial Persistence in Urinary Tract Infection Among Postmenopausal Population.

Urinary tract infections (UTIs) are common in older-aged women. Our study examined bacterial persistence with commonly prescribed antibiotics. Bacterial growth was demonstrated despite antibiotic treatment. The aims of this study were to quantify the bacterial persister phenotype in urine collected from postmenopausal women with acute and recurrent UTI and to determine the capabilities of first-line antibiotics to effectively treat persister cells. This was an institutional review board-approved cross-sectional analysis within a large academic referral center. Uropathogens were cultured from postmenopausal women with acute or recurrent UTI and screened for persister cells using persistence assays. Demographic and clinical variables were collected and analyzed. The entire experimental process was repeated in triplicate. Data were analyzed for significance (P < 0.05) between the persister culture and antibiotic treatments using a 1-way analysis of variance with multiple comparisons in Prism 9.3.0. Forty participants were included: 62.5% White, 22.5% Black, 3% Asian, and 2% Hispanic with a mean age of 72.3 ± 11.62 years. The persister phenotype was demonstrated in all of Escherichia coli isolates. Treatment with fosfomycin demonstrated reduced colony-forming units per milliliter compared with control (P < 0.01). Among recurrent isolates, there was a statistically significant decrease in colony-forming units per milliliter after antibiotic treatment with all 4 antibiotics (P < 0.05). This study demonstrated in vitro bacterial persistence in uropathogens from urogynecology patients despite treatment with commonly prescribed antibiotics. Fosfomycin generated the least amount of persister cells. Results suggest that persistence may be one bacterial defense mechanism involved in UTIs. Further research is needed to understand the clinical implications.

Stevia vs. triple antibiotic paste: An intracanal battle?

Intracanal medicaments are vital in treating the infections of the deciduous dentition due to the large percentage of accessory canals that hasten the microbial spread to the periradicular region. Though countless medicaments have been produced to reduce the microbial load and aid symptomatic relief, they still do not fulfill every function of an ideal medicament. The aim of the present study was to evaluate and compare the antimicrobial efficacy of Stevia rebaudiana (S. rebaudiana) and triple antibiotic paste (TAP) against Enterococcus faecalis (E. faecalis). The present in vitro, parallel, double-blinded study had an equal allocation ratio. The specimens were prepared, randomly divided into 4 groups and inoculated with E. faecalis (ATCC35550). Following incubation, the first 3 groups were treated with S. rebaudiana, triple antibiotic therapy or carbopol gel, respectively, with the 4th negative control group left untreated. The microbial samples were collected before and after treatment, and the counts of colony-forming units (CFUs) were compared. The results were analyzed using the Kruskal-Wallis, Dunn's post-hoc and Wilcoxon's signed rank tests. The first 2 groups displayed a significant decrease in CFUs after drug application, while the carbopol and control groups showed an exponential increase. There was no statistically significant difference between the stevia and TAP groups (p = 0.630). Stevia gel was comparable to TAP in terms of antimicrobial efficacy, and can therefore be considered a new alternative in intracanal treatment.

Antimycobacterial pyridine carboxamides: From design to in vivo activity

Tuberculosis is the number one killer of infectious diseases caused by a single microbe, namely Mycobacterium tuberculosis (Mtb). The success rate of curing this infection is decreasing due to emerging antimicrobial resistance. Therefore, novel treatments are urgently needed. As an attempt to develop new antituberculars effective against both drugs-sensitive and drug-resistant Mtb, we report the synthesis of a novel series inspired by combining fragments from the first-line agents isoniazid and pyrazinamide (series I) and isoniazid with the second-line agent 4-aminosalicylic acid (series II). We identified compound 10c from series II with selective, potent in vitro antimycobacterial activity against both drug-sensitive and drug-resistant Mtb H37Rv strains with no in vitro or in vivo cytotoxicity. In the murine model of tuberculosis, compound 10c caused a statistically significant decrease in colony-forming units (CFU) in spleen. Despite having a 4-aminosalicylic acid fragment in its structure, biochemical studies showed that compound 10c does not directly affect the folate pathway but rather methionine metabolism. In silico simulations indicated the possibility of binding to mycobacterial methionine-tRNA synthetase. Metabolic study in human liver microsomes revealed that compound 10c does not have any known toxic metabolites and has a half-life of 630 min, overcoming the main drawbacks of isoniazid (toxic metabolites) and 4-aminosalicylic acid (short half-life).

In vitro comparison of the effectiveness of various antimicrobial locks with taurolidine in the treatment and prevention of catheter-related bloodstream infections in patients receiving parenteral nutrition

ObjectivesTo evaluate the effectiveness of various taurolidine solutions in the prevention and treatment of catheter-related bloodstream infections (CRBSIs) caused by the entire spectrum of microbes in patients receiving parenteral nutrition in a shorter period of time. MethodsThe in vitro method was used to test for eradication of biofilm. Different locks were used: TauroSept (2%), TauroLock (1.35%), TauroLock half concentration, and 3.5% taurolidine and tested on Staphylococcus (S.) epidermidis, S. aureus, S. hominis, methicillin-resistant S. aureus (MRSA), Pseudomonas (P.) aeruginosa (PSAE), multidrug‐resistant P. aeruginosa (MR PSAE), vancomycin-resistant enterococci, Klebsiella pneumoniae producing carbapenemase (KPC), Klebsiella pneumoniae producing extended-spectrum beta-lactamase (KLPN ESBL), Candida (C.) albicans, and C. glabrata. Broviac catheters were incubated for growth of each organism and then incubated in lock solutions. Colony forming units (CFUs) were then counted after 30 min, 60 min, and 120 min of incubation. ResultsA statistically significant decrease in CFUs was observed after 30 min of taurolidine exposure for S. hominis, PSAE, KLPN ESBL, KLPN KPC, C. albicans, and C. glabrata; after 60 min of exposure for S. epidermidis, PSAE, MR PSAE, KLPN ESBL, KPC, C. albicans, and C. glabrata; and after 120 min of exposure for S. epidermidis, S. hominis, S. aureus, PSAE, MR PSAE, KLPN ESBL, KPC, C. albicans, C. glabrata. ConclusionsThe application of taurolidine is effective in the treatment of CRBSIs. Taurolidine proved to be more effective against Gram-negative microorganisms during a 30-min exposure. Using 0.675% taurolidine is still effective. To achieve the required antimicrobial effect, the catheter must be sanitized for at least 2 h.

Survival of bovine-associated serotypes of Salmonella enterica in bedding sand

Cattle persistently infected with bovine-adapted serotypes of Salmonella enterica are an important animal health and food safety issue. One possible mechanism by which infection is sustained in a dairy herd is by survival of Salmonella in sand used as bedding material. In this study we assessed the survival of 107 to 108 cfu bovine-associated serotypes of Salmonella enterica (sv. Cerro, Dublin, and Heidelberg) in sterile sand, recycled bedding sand, and gray water collected from a Wisconsin dairy farm. All 3 serotypes persisted at relatively high numbers (>106 cfu/g) for at least 28 d in sterile sand, with Salmonella sv. Dublin decreasing less than 1 log10 over 70 d. To our surprise, when low numbers of Salmonella sv. Dublin (103 cfu) were inoculated into sterile sand, the organism multiplied within 3 d to approximately 106 cfu/g sand and persisted at that level for 28 d. When we inoculated Salmonella sv. Dublin into recycled bedding sand or sand taken directly from cow pens, we observed a significant decrease in colony-forming units by d 7. In contrast, we observed a significant increase in colony-forming units when Salmonella sv. Dublin was inoculated into gray water from the sand recycling system. These data demonstrate that Salmonella can persist for extended periods of time in bedding sand, although this is limited to some extent by the native microbiota in recycled bedding sand.

A Comparative Study on the Effect of Spilanthes acmella and Chlorhexidine (0.2%) Mouth Rinses on Salivary Streptococcus mutans Count in Children

In the wake of an increased interest in finding natural alternatives for chemical medicinal products, this study assesses and compares the effects and acceptance of Spilanthes acmella, a widely used plant in various traditional systems of medicine, with Chlorhexidine (0.2%) mouth rinse on the dental caries causing pathogen Streptococcus mutans colonizing the oral cavity of children. The study included 40 healthy children in the age group of 8-12 years based on inclusion and extrusion criteria. In the beginning of the study, non-stimulated whole salivary samples were tested for the baseline count of colony forming units (CFU) of Streptococcus mutans using Mitis Salivarius Agar supplemented with potassium tellurite. The same process was repeated 24 hours after 15 days of regular use of mouth rinses twice daily. Results showed that there was statistically highly significant decrease in CFU in the post rinse phase in both the groups. S. acmella showed greater acceptance by study subjects when compared with the Chlorhexidine mouth rinse. It can be concluded based on the results of this study that S. acmella has beneficial effects against S. mutans and can be a potential option for preventive measures against dental caries, although more studies are needed for its validation.

Comparative Study of Antifungal Efficacy of Various Endodontic Irrigants with and without Clotrimazole in Extracted Teeth Inoculated with Candida albicans

To assess the application of clotrimazole (1%) as a complementary antifungal agent along with sodium hypochlorite (5.25%), chlorhexidine gluconate (2%), and doxycycline hydrochloride (5%) against Candida albicans. Seventy freshly extracted single-rooted premolars with matured apices were collected, stored, and handled according to the Occupational Safety and Health Administration (OSHA) and the Center for Disease Control and Prevention (CDC) guidelines and recommendations. These were divided into three groups (two tests and one control group) depending on irrigants used. The efficacy of each irrigant group was compared. The observations were statistically analyzed by the multiple intergroup comparisons using ANOVA and Scheffe multiple comparisons (p < 0.001). The sodium hypochlorite (group IA-mean 129.6) has shown a statistically significant decrease in colony-forming units (CFUs) (p < 0.01) on comparison with chlorhexidine [(IB) mean 190.2]. A similar result was obtained in comparison with the sodium hypochlorite group (IA) and doxycycline HCl group [(IC) mean 318.4] and also between the sodium hypochlorite group (IA) and the control group [(III) mean 554.2]. The intragroup comparison of group II, group IIA (mean 63.3), and group IIB (mean 73.8) showed no statistically significant difference. Group III (mean 554.2) was the least effective of all the subgroups. Sodium hypochlorite showed better antifungal efficacy than chlorhexidine and doxycycline when used alone. The addition of clotrimazole increased the efficiency of doxycycline also, but it was less compared to sodium hypochlorite and chlorhexidine. Within the limitations of this study, the inclusion of 1% clotrimazole increased the antifungal efficacy of all the three irrigants. Our study compared the efficacy of the various endodontic irrigants and also determined their efficiency with the addition of the antifungal agent. Clotrimazole (1%) addition in irrigating solutions showed better results and promoted faster healing.

Impact of Photobiomodulation and Condition Medium on Mast Cell Counts, Degranulation, and Wound Strength in Infected Skin Wound Healing of Diabetic Rats.

Background: Numerous people suffer from diabetes mellitus (DM) and resultant diabetic foot ulcers (DFU), which lack effective treatment. Photobiomodulation (PBM) has accelerated wound healing in diabetic animals and patients in some studies. However, there is scant information on the number and activation state of skin mast cells (MCs) in PBM-treated diabetic wounds. Objective: We intend to assess the influence of the number of MCs and degranulation in the remodeling step of an infected wound model on wound strength and its microbial flora in a type 1 DM (T1DM) rat model by administration of PBM, condition medium (CM) derived from human bone marrow mesenchymal stem cells (hBMMSCs), and the combination of PBM+CM. Methods: We prepared CM by culturing hBMMSCs. T1DM was induced in 72 rats and, after 1 month, we created one excisional wound in each rat. All wounds were infected with methicillin-resistant Staphylococcus aureus (MRSA). We divided the rats into four groups: (n = 18): (i) control; (ii) PBM; (iii) CM, and (iv) PBM+CM. On days 4, 7, and 15, we conducted microbiological, tensiometrical, and stereological analyses. The type of MCs (T1MCs, T2MCs, or T3MCs) and total number of MCs (TOMCs) were counted by light microscopy. Results: On day 15, the PBM+CM, PBM, and CM groups had significantly increased wound strength compared with the control group. There was a significant decrease in colony-forming units (CFU) at all time points in the PBM+CM and PBM groups. The PBM+CM and PBM groups had more stable MCs (T1MCs), less significant degranulated MCs (T2MCs), less significant disintegrated MCs (T3MCs), and less significant TOMCs compared with the control group at all time points. Conclusions: PBM+CM and PBM treatments significantly increased the healing process in an ischemic and MRSA-infected wound model of T1DM rats. PBM+CM and PBM significantly decreased both TOMCs and their degranulation, and significantly decreased CFU.

Optimal Irrigation and Debridement of Infected Total Joint Implants with Chlorhexidine Gluconate

Previous study at our institution demonstrated that scrubbing a methicillin-resistant Staphylococcus aureus (MRSA)-coated titanium disk with chlorhexidine gluconate (CG) solution achieved superior biofilm eradication compared to alternative solutions. The current study aimed to identify the minimum CG concentration for effective bacteria eradication of an in vitro periprosthetic joint infection (PJI) model. MRSA colony-forming units (CFUs) were counted following simulated irrigation and debridement with varying CG solutions before and after a 24-hour reincubation period. Significant decrease was noted on all disks before reincubation. Postreincubation, significant decrease in CFUs was found in the 4% and 2% groups. This study demonstrated that I+D of an infected PJI model with 4% CG solution was effective at treating MRSA biofilm at concentrations as low as 2%.

In vitro and ex vivo antimicrobial efficacy of nano-MgO in the elimination of endodontic pathogens.

The use of metal oxide nanoparticles has attracted lots of attention, mostly because of their promising antimicrobial activity along with their biocompatibility with mammalian cells. This study aims to investigate the in vitro and ex vivo antimicrobial efficiency of nano-magnesium oxide (MgO) aqueous solution against endodontic pathogens. The cytotoxicity of different concentrations of nano-MgO was assessed using lactate dehydrogenase cytotoxicity assay (LDH assay). A comparison of the antimicrobial efficiency of several concentrations of nano-MgO solution, sodium hypochlorite (NaOCl), and chlorhexidine (CHX) gluconate against Staphylococcus aureus, Enterococcus faecalis, and Candida albicans was made using the direct contact method. An ex vivo model of decoronated and experimentally infected human teeth was employed to compare the efficiency of nano-MgO (5 mg/L) solution with NaOCl (5.25 %) in the elimination of E. faecalis. There was no statistically significant difference between nano-MgO solutions (10 and 5 mg/L), 5.25 % NaOCl, and 2 % CHX gluconate in terms of the required time to inhibit the growth of the tested pathogens (p > 0.05). The LDH assay showed no cytotoxicity of different concentrations of nano-MgO used in this study (p < 0.001). In the ex vivo model of infected human teeth, 6 h post-irrigation, there was no statistically significant difference between colony-forming units (CFU) per milliliter of nano-MgO (5 mg/L) and NaOCl (5.25 %)-treated teeth (5-6 log scale reduction). However, the nano-MgO group showed a significant decrease in colony-forming units per milliliter (7 log scale), 24 h post-irrigation (p < 0.05). At other tested time points-24, 48, 72, and 168 h-the levels of CFU per milliliter were significantly less in the nano-MgO group (2-3 log scale difference) compared to the NaOCl group, indicating long-term antibacterial activity of nano-MgO (p < 0.05). At 72 and 168 h post-irrigation, no detectable bacterial growth was observed in the nano-MgO group. The detection limit was 10 CFU/mL. Nano-MgO aqueous solutions represent promising antimicrobial activities, both in vitro and ex vivo with minimal toxicity. Compared to NaOCl (5.25 %), nano-MgO (5 mg/L) exhibits statistically significant long-term efficiency in the elimination of E. faecalis in the root canal system. After further investigations, nano-MgO could be considered as a new root canal irrigant.

Anti‐biofilm Effects of Honey Against Wound Pathogens Proteus mirabilis and Enterobacter cloacae

Biofilm growth and its persistence within wounds have recently been suggested as contributing factors to impaired healing. The goal of this study was to investigate the anti-biofilm effects of several honey samples of different botanical origin, including manuka honey against Proteus mirabilis and Enterobacter cloacae wound isolates. Quantification of biofilm formation was carried out using a microtiter plate assay. All honeys at a sub-inhibitory concentration of 10% (w/v) significantly reduced the biofilm development of both isolates. Similarly, at a concentration of 50% (w/v), each of the honeys caused significant partial detachment of Pr. mirabilis biofilm after 24 h. On the other hand, no honey was able to significantly detach Ent. cloacae biofilm. In addition, treatment of Ent. cloacae and Pr. mirabilis biofilms with all honeys resulted in a significant decrease in colony-forming units per well values in a range of 0.35-1.16 and 1.2-7.5 log units, respectively. Of the tested honeys, manuka honey possessed the most potent anti-biofilm properties. Furthermore, methylglyoxal, an antibacterial compound of manuka honey, was shown to be responsible for killing biofilm-embedded wound bacteria. These findings suggest that manuka honey could be used as a potential therapy for the treatment of wounds containing Pr. mirabilis or Ent. cloacae.

白色LED照射による&lt;i&gt;Porphyromonas gingivalis&lt;/i&gt;の殺菌効果

Photodynamic therapy (PDT) is a medical treatment for cancers and infections with light irradiation and photosensitizers, which are excited by being exposed to light of a specific wavelength. Recently, PDT is applied to the treatment of periodontal disease. In this study, we investigated the bactericidal effect against Porphyromonas gingivalis, which is a periodontopathogenic bacteria, by white LED (light-emitting diode) irradiation with a higher visibility in the oral cavity. P. gingivalis (ATCC33277) was anaerobically cultured in brain-heart infusion (BHI) media, adjusted to an optical density of 0.3 using a photoelectrometer, and was then used as the bacterial solution for this experiment. After the bacterial solution was dispensed into a 96-well, clear, flat-bottom plate at 100 μL/well, the samples were irradiated with a white LED (irradiation intensities: 10, 20, 30 J/cm2, irradiation distance: 15 mm). The bacterial solutions were diluted and anaerobically cultured on blood agar at 37°C for 7 days. Then, the colony forming units (CFU) were counted and compared to that of the control group (LED non-irradiation) to determine the bactericidal effect. Irradiation with the white LED resulted in a statistically significant decrease in CFU, with the number of CFU decreasing as the irradiation intensity increased. In the second part of the study, we examined two photosensitizers: Protoporphyrin IX and Fluorescein, for use in PDT with white LED as a light source. The irradiation intensity of white LED was set at 20 J/cm2, and the concentration of each of the photosensitizers was set at 100 μM. A photosensitizer group (addition of the bacterial solution with photosensitizer and LED non-irradiation), an LED-irradiated group (bacterial solution alone and LED irradiation) and a combination group (addition of the bacterial solution with photosensitizer and LED irradiation) were compared to a control group (bacterial solution alone and LED non-irradiation), with the bactericidal effect evaluated by CFU measurements as described above. Neither of the photosensitizers affected the bactericidal effect. On the other hand, CFU of the combination group showed a statistically significant decrease compared to that of the LED-irradiated group. These results indicate that white LED irradiation has a bactericidal effect against P. gingivalis, and suggest that PDT with a combination of white LED irradiation and Protoporphyrin IX or Fluorescein added as a photosensitizer increase the bactericidal effect more than white LED irradiation alone.

Antibacterial effect of calcium hydroxide on intraluminal and intratubular enterococcus faecalis.

Root canal treatment involves the elimination of intraradicular microorganisms. Calcium hydroxide [Ca(OH)(2)] is the most widely used canal dressing material. Enterococcus faecalis (E. faecalis) has been reported to be resistant to Ca(OH)(2) in-vivo. The purpose of this study was to evaluate the efficacy of Ca(OH)(2) on the elimination of intraluminal and intratubular E. faecalis. Thirty six human single-rooted teeth were contaminated with E. faecalis. Thirty specimens in the experimental group were treated with 10% Ca(OH)(2); six specimens were treated with normal saline as the positive control (n=6). Specimens from experimental group were randomly divided into two subgroups of 15 each. In subgroup A, specimens were incubated and sampled after one day and in subgroup B, they were tested at day seven. Paper points and Gates Glidden burs were used to obtain the intraluminal and intratubular E. faecalis respectively. Samples obtained from these root canal preparations were analyzed for bacterial load by counting the number of colony forming units (CFUs). Mann-Whitney and t-test were used for analysis. Group B had significant decrease in CFUs compared with group A with both sampling methods (P<0.001). No differences were observed between the antimicrobial properties of Ca(OH)(2) against intraluminal and intratubular E. faecalis. After 1 week, there was a significant reduction in CFU load with Ca(OH)(2) intra canal medication. Ca(OH)(2) showed the same antimicrobial efficacy on intraluminal and intratubular E. faecalis.

Effectiveness of the Proton Pump Inhibitor Omeprazole Associated with Calcium Hydroxide as Intracanal Medication: An In Vivo Study

Introduction The objective of this study was to evaluate the efficacy of the association of a proton pump inhibitor (omeprazole) with Ca(OH) 2 as intracanal medication in a rat model of periapical lesions. Methods Periapical lesions were induced on the first right mandibular molar tooth of 36 male Wistar rats (6 per group). After 28 days, the distal canal of each tooth was prepared, filled with the respective dressing (negative control group, PEG 400; positive control group, Ca(OH) 2 + PEG400; test group, Ca(OH) 2 + omeprazole + PEG 400), and sealed with amalgam for 15 or 28 days. Microbiological samples were taken in 3 periods: S1, after 28 days of lesion induction; S2, after the biomechanical preparation; and S3, after the medication (15 and 28 days). Results The radiographic and histologic analysis revealed that either Ca(OH) 2 or Ca(OH) 2 plus omeprazole dressings produced a reduction of periapical lesions at 28 days, when compared with the negative control group. The reduction of periapical lesions and inflammatory cell infiltration was visibly improved by associating omeprazole with Ca(OH) 2, with an increase of reparative bone areas. The microbiological assessment showed a significant decrease of colony-forming units count from S1 to S2 or S3 collecting times, but no differences were observed between the S2 and the S3 time-periods or among the experimental groups within the S3 period. Further bacterial characterization showed a possible selective activity of the medications. Conclusions Our data showed that association of omeprazole with Ca(OH) 2 favored a superior repair of rat periapical lesions and seemed to display different selective activity over endodontic microbiota, in comparison with the conventional Ca(OH) 2 dressing.

Dying in Yoghurt: The Number of Living Bacteria in Probiotic Yoghurt Decreases under Exposure to Room Temperature

Background/Aims: While probiotic bacteria are successfully used in the treatment of ulcerative colitis, the effect of commercially available probiotic products is still controversial. Here, we study whether the number of living probiotic bacteria in yoghurts is altered by an interruption of the cold chain. Methods: Three commonly available probiotic yoghurts were kept at 4°C or put at room temperature (RT) for 6 h or 24 h. An aliquot of each yoghurt was applied on Man-Rogosa-Sharpe agar and incubated at 37°C for 48 h. Colony forming units (CFU) were counted by microscopy. Results: The first yoghurt, containing Lactobacillus johnsonii, showed a significant decrease in CFU after 6 h of storage at RT, which was further pronounced after 24 h. The number of CFU of the second yoghurt, containing Lactobacillus GG, was also decreased after 6 h and further diminished after 24 h at RT. From the third yoghurt, containing Lactobacillus acidophilus, only 53.8% of the CFU remained after 6 h at RT; after 24 h, only about one fourth of the CFU were found. Conclusions: Our data demonstrate that the number of living probiotic bacteria in yoghurt products decreases dramatically after exposure to RT. This represents an important information for consumers of such products.

Phototoxicity assessment of drugs and cosmetic products using E. coli

A gram negative bacteria Escherichia coli (Dh5α strain) was developed as an alternate test system of phototoxicity. Eight drugs (antibiotics) and cosmetic products (eight face creams) were examined for their phototoxicity using this test system. Five known phototoxic compounds were used to validate the test system. UVA-radiation induced phototoxicity of these compounds was tested by agar gel diffusion assay. Decrease in colony forming units (CFU) was taken as an end point of phototoxicity. The phototoxic compounds and antibiotics produced significant reduction in CFU ( p < 0.001) at 80 μg/ml concentrations under exposure to UVA-radiation (5.4–10.8 J/cm 2). One face cream was found phototoxic and produced significant decrease in CFU of E. coli at 1.0 mg/ml concentration under UVA exposure (10.8 J/cm 2). The minimum effective concentration of tetracycline and dose of UVA-radiation were also determined by observing growth inhibition of E. coli through disc diffusion assay. The observations suggested that E. coli can be used as an alternative test system for phototoxicity evaluation of chemicals. A battery of test systems is required to conclude the toxic/phototoxic potential of a chemical agent. In view of the speed, easiness, sensitivity and low cost, E. coli is introduced as one of the alternate test system for phototoxicity studies in safety evaluation of various chemical ingredients or formulations used in cosmetics and drugs.

Experimental intraabdominal candidiasis in rabbits: therapy with low-total-dose intravenous amphotericin B.

By using a recently developed rabbit model, we examined the efficacy of relatively low-total-dose intravenous amphotericin B (Am-B; 7 to 14 mg/kg) in the treatment of intraabdominal candidiasis due to Candida albicans. Forty-eight percent of the rabbits developed evidence of hematogenously disseminated infection (Candida endophthalmitis) before therapy. By day 7 of therapy, there was a significant decrease in the mean log10 colony-forming units per gram of peritoneal abscess in comparison with both pretherapy cultures and concomitantly sacrificed controls (no Am-B treatment; P less than 0.25). By day 11 of therapy, peritoneal abscesses were sterilized by Am-B, whereas control rabbit cultures remained positive. In contrast, low-dose Am-B therapy produced no significant decrease in colony-forming units per gram of renal or chorioretinal abscess in rabbits which developed hematogenously disseminated candidiasis. Serum Am-B levels approached or exceeded the minimal fungistatic concentrations for this C. albicans strain in most animals tested. Low-dose Am-B was effective in eradicating intraabdominal candidiasis, but was not curative when extraperitoneal dissemination occurred.