Reduction In Colony-forming Units Research Articles

Photochemical eradication of methicillin-resistant Staphylococcus aureus by blue light activation of riboflavin.

To compare elimination of methicillin-resistant Staphylococcus aureus (MRSA) by exposure of blue light alone and with riboflavin. A reference strain of MRSA was cultured and diluted in PBS with and without riboflavin (0.01%). Fifteen microlitre was added on a microscope slide, creating a fluid layer with a thickness of around 400 microns. Both of the bacterial suspensions were exposed to blue light, and the effect between exposure with and without riboflavin was compared. Evaluation involved two different wavelengths (412 and 450nm) of blue light with a lower (5.4J/cm2 ) and higher dose (approximately 28.5J/cm2 ). The effect of 412nm light was also evaluated for a thicker fluid layer (1.17mm). After exposure, colony-forming units (CFUs) were determined for each solution. All measurements were repeated eight times. The reductions in bacteria were similar for both wavelengths. With riboflavin, a statistically significant elimination was observed for both 412 and 450nm (p<0.001). At both dosages, the mean reduction was more pronounced with the presence of riboflavin than without it. Using the higher dose, CFU reduction was 99% and 98%, respectively, for 412 and 450nm light. The bactericidal efficacy was high also in the deeper fluid layer (93%, higher dose). Riboflavin enhanced the antibacterial effect on the exposed MRSA strain of blue light for both 412 and 450nm blue light. This indicates that blue light could be considered for possible implementation in deep corneal infections.

Physiological and Transcriptome Response of the Polycyclic Aromatic Hydrocarbon Degrading Novosphingobium sp. LH128 after Inoculation in Soil.

Soil bioaugmentation involves the inoculation of pollutant-degrading bacteria to accelerate pollutant degradation. Often the inoculum shows a dramatic decrease in Colony Forming Units (CFU) upon soil inoculation but this behavior is not well-understood. In this study, the physiology and transcriptomic response of a GFP tagged variant of Novosphingobium sp. LH128 was examined after inoculation into phenanthrene spiked soil. Four hours after inoculation, strain LH128-GFP showed about 99% reduction in CFU while microscopic counts of GFP-expressing cells were identical to the expected initial cell density, indicating that the reduction in CFU number is explained by cells entering into a Viable But Non-Culturable (VBNC)-like state and not by cell death. Transcriptome analysis showed a remarkably higher expression of phenanthrene degradation genes 4 h after inoculation, compared to the inoculum suspension concomitant with an increased expression of genes involved in stress response. This indicates that the cells were active in phenanthrene degradation while experiencing stress. Between 4 h and 10 days, CFU numbers increased to numbers comparable to the inoculated cell density. Our results suggest that strain LH128-GFP enters a VBNC-like state upon inoculation into soil but is metabolically active and that VBNC cells should be taken into account in evaluating bioaugmentation approaches.

New Irradiation Method with Indocyanine Green-Loaded Nanospheres for Inactivating Periodontal Pathogens.

Antimicrobial photodynamic therapy (aPDT) has been proposed as an adjunctive strategy for periodontitis treatments. However, use of aPDT for periodontal treatment is complicated by the difficulty in accessing morphologically complex lesions such as furcation involvement, which the irradiation beam (which is targeted parallel to the tooth axis into the periodontal pocket) cannot access directly. The aim of this study was to validate a modified aPDT method that photosensitizes indocyanine green-loaded nanospheres through the gingivae from outside the pocket using a diode laser. To establish this trans-gingival irradiation method, we built an in vitro aPDT model using a substitution for gingivae. Irradiation conditions and the cooling method were optimized before the bactericidal effects on Porphyromonas gingivalis were investigated. The permeable energy through the gingival model at irradiation conditions of 2 W output power in a 50% duty cycle was comparable with the transmitted energy of conventional irradiation. Intermittent irradiation with air cooling limited the temperature increase in the gingival model to 2.75 °C. The aPDT group showed significant bactericidal effects, with reductions in colony-forming units of 99.99% after 5 min of irradiation. This effect of aPDT against a periodontal pathogen demonstrates the validity of trans-gingival irradiation for periodontal treatment.

Action of an Argon/Water Vapor Plasma Jet in the Sterilization of Silicone Contaminated with Candida albicans

This work evaluates the influence of argon/water vapor plasma jet exposure time on surface sterilization of a silicone substrate contaminated with Candida albicans. For this purpose, gliding arc-type geometry was used to generate a nonthermal plasma jet at an applied power on the order of 20 W under water vapor carried by an argon flow of 5 L/min. C. albicans biofilms were grown on silicone plates with a 2cm2 area. Samples were treated with a plasmajet for different exposure times, resulting in the following sample groups: nontreated (A) or treated with plasma for 2 min (B), 5 min (C), 10 min (D), and 20 min (E). Experiments were performed in triplicate. To evaluate the action of the plasma jet on the contaminated samples, colony-forming units (CFUs) were counted before and after plasma exposure. Scanning electron microscopy (SEM) was used to analyze the morphological modification of the treated substrate, whereas Fourier transform infrared spectroscopy (FT-IR) was used to analyze the bare substrate after exposure to plasma. Optical emission spectroscopy was used to investigate the plasma species in the ultraviolet range. Results indicated reductions in CFUs of 42.4%, 74.2%, 83.7%, and 97.5% for groups B, C, D, and E, respectively. SEM images showed that groups D and E suffered more external cellular changes with shriveled, swollen, and/or deformed aspects. These effects can be attributed to reactive species in the plasma such as hydroxyl radicals (OH), which were increased considerably with the presence of water vapor in the mixture with argon gas. A quality change in the surface of the silicone material after 20 min of plasma treatment was observed with the results of the SEM and FT-IR analyses. Finally, the argon/water plasma jet promoted only a slight increase in substrate temperature (up to 310 K) for the investigated conditions, which is very convenient for thermal-sensitive material sterilization.

Efficacy Evaluation of Iclaprim in a Neutropenic Rat Lung Infection Model with Methicillin-Resistant Staphylococcus aureus Entrapped in Alginate Microspheres

BackgroundThe objective of this study was to demonstrate the effect of iclaprim, a new generation diaminopyrimidine, in a neutropenic rat lung infection model with methicillin resistant Staphylococcus aureus (MRSA).Methods S. aureus strain AH1252, a thymidine knockout of the MRSA wild type AW6 strain, was utilized for this study. The bacterial strain was diluted in a 2% alginate buffer, which was added dropwise in a ratio of 1:5 into 50 mM MgCl to form alginate beads. The alginate beads reduce the efficacy of bacterial clearance similar to that seen in the cystic fibrosis population. A 5.25 × 104 bacterial inoculum was administered intratracheally to groups of 9 rats with prepared alginate bacteria suspensions, under isoflurane anesthesia. Beginning 2 hours post infection, rats received either iclaprim or vancomycin for 3 days via subcutaneous injection every 12 hours. Twelve hours after the last treatment, rats were euthanized and lungs collected for CFU determination.ResultsThe Table below shows survival, CFU/gram of lung, and change in CFUs (Standard Error of the Mean (S.E.M.) from baseline by treatment or vehicle group.ConclusionIn this rat lung infection model increased survival was observed in both iclaprim and vancomycin treatment groups, compared with the infection controls. Rats receiving iclaprim demonstrated a 5.34 log10 CFU reduction from the 72 hour infection whereas vancomycin-treated rats showed a 3.38 log10 CFU reduction from the 72 hour infection controls.#8232;Based on these data, further evaluation of iclaprim for S. aureus lung infections among the cystic fibrosis population is warranted.Disclosures D. Huang, Motif Bio: Employee, Salary

Evaluation of the Efficacy of CD101, a Novel Echinocandin, in the Treatment of Candida auris Infection Using a Murine Model of Disseminated Candidiasis

BackgroundThe first case of an invasive infection caused by C. auris was reported in July of 2016. Multiple cases have since been reported with high mortality rates due to the multidrug-resistant nature of C. auris. Although C. auris shows increased susceptibility to the echinocandin class of antifungals, the use of these drugs is restricted to multiple IV administrations. CD101 is a novel echinocandin with enhanced stability and pharmacokinetics, allowing for once weekly high dose administration. In this study, we evaluated the efficacy of CD101 in the treatment of disseminated C. auris infection using a murine model of disseminated candidiasis.MethodsFemale 6–8 week old CD-1 mice were immunosuppressed with cyclophosphamide (200 mg/kg) 3 days prior to infection and 150 mg/kg 1 day post-infection. On the day of infection, mice were inoculated with 3 x 107C. auris blastospores via the lateral tail vein. Mice were randomized into 5 groups (n = 5 for colony forming units (CFU) and n = 10 for survival): CD101 20 mg/kg administered by intraperitoneal (IP) injection, fluconazole 20 mg/kg administered per os (PO), amphotericin B 0.3 mg/kg IP, and a vehicle control. Treatments were administered 2 hours post-infection (day 1) and again on day 4 of the study for a total of 2 doses. Mice were monitored daily and a survival curve was generated. CFU groups were sacrificed on day 8 of the study. One kidney was removed from each mouse, homogenized, plated on potato dextrose agar (PDA), and incubated at 35°C for 2 days to determine CFU. The remaining survival mice were monitored until the end of the study (day 14).ResultsCD101 showed an average 3 log reduction in kidney CFU compared with fluconazole, amphotericin B, and vehicle treated groups, which was statistically significant (P = 0.03, 0.03, and 0.04, respectively). At the end of the study, percent survival of mice in CD101, fluconazole, amphotericin B, vehicle, and untreated groups was 80, 0, 30, 20, and 0%, respectively (Figure 1).ConclusionTaken together, our findings show that CD101 possesses potent antifungal activity against C. auris infection in a disseminated model of candidiasis. Additionally, treatment with CD101 resulted in a significantly higher overall percent survival. Further investigation of this drug is warranted.Figure 1.Survival curve of mice in all treatment groups after 14 days.Disclosures M. Ghannoum, Amplyx Pharmaceuticals: Consultant, Research Contractor and Scientific Advisor, Consulting fee and Research grant; Cidara Therapeutics: Consultant and Research Contractor, Consulting fee and Research grant

Antibacterial efficacy of several intracanal medicaments for endodontic therapy.

The antibacterial efficacy of intracanal medicaments for 2 and 7 days, in open apex root canals contaminated with Enterococcus faecalis biofilms was compared. One hundred and thirty-eight standardized uniradicular human roots were inoculated with E. faecalis. Colony forming units (CFU) were recorded before and after medication. Samples were divided in two (2/7 days), and subdivided (n=8/group): triple antibiotic paste (TAP); double antibiotic paste (DAP); dental base paste (DBP), consisting of calcium hydroxide, propylene glycol and calcium carbonate; DBP+0.2% chlorhexidine (CHX); DBP+0.2% cetrimide (CTR); DBP+0.2% CHX+0.2% CTR; 2.5% sodium hypochlorite (NaOCl); and distilled water. At both periods TAP, DAP, DBP+0.2% CHX, DBP+0.2% CTR and DBP+0.2% CHX+0.2% CTR exhibited no growth (NG) of E. faecalis. Distilled water and 2.5% NaOCl obtained the lowest CFU reduction. No growth with DBP was reached only at 7 days. CHX and/or CTR pastes were as effective as DAP and TAP. A 2-day period provided an effective disinfection.

Surface Disinfectants for Burn Units Evaluated by a New Double Method, Using Microorganisms Recently Isolated From Patients, on a Surface Germ-Carrier Model.

Assessment methods of surface disinfection based on international standards (Environmental Protection Agency, European Norms, etc) do not correspond to hospital reality. New evaluation methods of surfaces disinfection are proposed to choose the most suitable disinfectant to act against clinically relevant microorganisms detected on the surfaces of burn units. 1) "Immediate effect": 6 products were compared using a glass germ-carrier and 20 recently isolated microorganisms from different patients in the intensive care units. Disinfectants were applied with microfiber cloths. Log10 reductions were calculated for colony forming units produced after 15 minutes of disinfectant application. 2) "Residual effect": the glass germ-carriers were previously impregnated with one of the studied disinfectants. After a 30-minute wait period, they were then contaminated with 1 microorganism (from the 20 above-mentioned). After 15 minutes, the disinfectant was inhibited and the log10 reduction of colony forming units was assessed. The immediate effect (disinfection and microorganism dragging and transferring from the surface to the cloth) produced complete elimination of the inoculums for all products used except one (a diluted quaternary ammonium). The average residual effect found on the 20 microorganisms was moderate: 2 to 3 log10 colony forming unit reduction with chlorine dioxide or 0.5% chlorhexidine (and lower with the other products), obtaining surfaces refractory to recontamination, at least, during 30 minutes. Two tests should be performed before advising surface disinfectant: 1) direct effect and 2) residual efficacy. These characteristics should be considered when a new surface disinfectant is chosen. Chlorine dioxide has a similar or better direct effect than sodium hypochlorite and a similar residual effect than chlorhexidine.

Development of a sensitive and false-positive free PMA-qPCR viability assay to quantify VBNC Escherichia coli and evaluate disinfection performance in wastewater effluent

The detection and quantification of viable Escherichia coli cells in wastewater treatment plant effluent is very important as it is the main disinfection efficacy parameter for assessing its public health risk and environmental impact. The aim of this study was to develop a sensitive and false-positive free propidium monoazide-quantitative polymerase chain reaction (PMA-qPCR) assay to quantify the viable but non-culturable (VBNC) E. coli present in secondary wastewater effluent after chlorine disinfection. The qPCR target was the E. coli uidA gene, and native Taq was used to eliminate false positives caused by the presence of contaminant E. coli DNA in recombinant Taq polymerase reagents. Due to issues with qPCR inhibitors in wastewater, this study explored several pre-DNA extraction treatment methods for qPCR inhibitor removal. PMA-qPCR validation was done using salmon testes DNA (Sketa DNA) as an exogenous control added directly to the wastewater samples and amplified using a separate qPCR assay. After disinfection of secondary effluent with 2ppm chlorine at the plant, the mean Log10 CFU reduction in E. coli was 2.85 from a mean CFU of 3.48/10mL compared to 0.21 Log10 CCE mean reduction of the uidA gene from a mean CCE of 3.16/10mL. The VBNC cell concentrations were calculated as 2.32 Log10/10mL by subtracting the colony forming units (CFU) obtained from membrane filtration from the calculated CFU equivalent (CCE) values obtained from PMA-qPCR. These results demonstrate the effective use of a PMA-qPCR method for the quantification of the E. coli uidA gene and indicate there are high numbers (2.01×103CCE/100mL) of VBNC E. coli cells leaving the wastewater treatment plant in the final effluent after chlorine treatment. VBNC bacterial cells are of concern as they have the potential to resuscitate and grow, regain virulence, affect natural microbiome in the discharge sites, and pass on antimicrobial resistant genes to other microorganisms.

Antimicrobial and wear performance of Cu-Zr-Al metallic glass composites

The antimicrobial and wear behaviour of metallic glass composites corresponding to the Cu50+x(Zr44Al6)50−x system with x=(0, 3 and 6) has been studied. The three compositions consist of crystalline phases embedded in an amorphous matrix and they exhibit crystallinity increase with increasing Cu content, i.e., decrease of the glass-forming ability. The wear resistance also increases with the addition of Cu as indirectly assessed from H/Er and H3/Er2 parameters obtained from nanoindentation tests. These results are in agreement with scratch tests since for the alloy with highest Cu content, i.e., Cu56Zr38.7Al5.3, reveals a crack increase, lower pile-up, prone adhesion wear in dry sliding and higher scratch groove volume to pile-up volume. Samples with higher Cu content revealed higher hydrophilicity. Time-kill studies revealed higher reduction in colony-forming units for E. coli (gram-negative) and B. subtilis (gram-positive) after 60min of contact time for the Cu56Zr38.7Al5.3 alloy and all the samples achieved a complete elimination of bacteria in 250min.

Antibacterial Efficacy of a New Sonic Irrigation Device for Root Canal Disinfection

IntroductionPassive ultrasonic irrigation (PUI) is the most widespread method used to activate irrigation solutions. Concerns have been raised that PUI is less effective in curved root canals and is not passive at all. Our aim was to compare a novel passive sonic irrigation (PSI) device (6000 Hz) with PUI and manual irrigation (MI) with respect to their efficiency in removing different endodontic microorganisms from curved and straight root canals. MethodsWe performed 2 experiments as follows. In a 3-day infection model, we included 8 groups of single or dual microbial species that were rinsed with 0.9% sodium chloride using PSI, PUI, or MI. Colony-forming units (CFUs) were counted after incubation, and log10 transformations were performed for statistical comparisons. In a 21-d infection model, we tested the same irrigation protocols on 4 groups of microorganisms and used 1.5% sodium hypochlorite as an irrigant. Infection control samples were taken at day 0, 3, 5, and 7 after treatment and were subsequently reincubated. ResultsUsing sodium chloride as an irrigant, the amount of reduction in CFUs compared with the negative control was approximately 3 log10 units for PSI at 6000 Hz, 2 log10 units for PUI, and 1 log10 unit for MI. PSI reduced the microorganism CFUs significantly better than PUI. Using sodium hypochlorite led to a significant reduction in microorganism CFUs even with MI. After 3 days, compared with MI, microorganism regrowth significantly reduced after PSI and PUI treatment, but in these groups, in at least half of the samples, microorganisms were detectable after 7 days. ConclusionsPSI at 6000 Hz might be at least equal to PUI with respect to reduction of the microbial load in curved and straight root canals.

Can ultraviolet light C decrease the environmental burden of antimicrobial-resistant and -sensitive bacteria on textiles?

The environment is important in transmission of bacteria. Textiles are difficult and time consuming to clean; ultraviolet light C (UVC) is germicidal and may be an effective disinfection method for textile surfaces. This study evaluated the efficacy of UVC, a commercial quaternary ammonium compound antimicrobial spray (FAS) and UVC+FAS combined for reducing bacterial colonization on experimentally contaminated textiles. Microfibre, cotton and polyester were inoculated with meticillin-sensitive and -resistant Staphylococcus aureus (MSSA and MRSA), Staphylococcus pseudintermedius (MSSP and MRSP), Pseudomonas aeruginosa or Escherichia coli. ATCC® strains were used except for MRSP, for which ten canine clinical isolates were collected. Textiles were treated with three doses of UVC (13 mJ/cm2 , 54 mJ/cm2 or 270 mJ/cm2 ), FAS or both (FAS and UVC at 270 mJ/cm2 ). UVC was delivered using a modified mercury-based lamp. Bleach (8.25%) was used as a positive control. Negative controls received no treatment. Surface bacterial counts were determined 24 h post-treatment. The lower dosages (13 mJ/cm2 and 54 mJ/cm2 ) of UVC had >90% colony forming unit (CFU) reduction, 270 mJ/cm2 had >99% CFU reduction and combined UVC+FAS had 100% CFU reduction against all bacterial strains on all surfaces (P < 0.05). Ten experiments showed that treatment with UVC had a greater CFU reduction when compared to FAS alone (P < 0.05). A majority of those experiments (seven of 10) involved Gram-negative species (P. aeruginosa or E. coli). UVC quickly reduced the bacterial burden on textiles to greater than 90%; UVC may be a better disinfecting agent than FAS for Gram-negative species.

Interactions of linezolid and second-line anti-tuberculosis agents against multidrug-resistant Mycobacterium tuberculosis in vitro and in vivo

The objectives of this study were to evaluate the interactions between linezolid (LZD) and second-line anti-tuberculosis (TB) agents in susceptible and multidrug-resistant (MDR) TB in vitro, and to validate the in vitro results in a murine TB model. The minimum inhibitory concentrations of LZD and seven second-line anti-TB drugs against H37Rv and three multidrug-resistant clinical isolates were determined by Alamar Blue assay, and the interaction patterns of LZD and the seven second-line anti-TB agents against the four isolates were studied using a dynamic checkerboard method. The activities of these combinations against Mycobacterium tuberculosis were evaluated in a murine model of TB. The combination of LZD + capreomycin exhibited partial synergism for three of four isolates, LZD + para-aminosalicylic acid exhibited partial synergism for two of four isolates, and LZD + levofloxacin and LZD + amikacin exhibited partial synergism for one of four isolates; all other combinations showed indifference or an additive effect in vitro. The activities of six combinations and the standard regimen rifampicin + isoniazid + pyrazinamide were investigated in a murine model of TB (infection with H37Rv). Significant reductions in colony-forming units (CFU) were found in LZD + capreomycin and LZD + clofazimine groups when the CFU in the lungs on day 0 (the day of beginning treatment) was compared with the CFU in the lungs after 2 months of treatment. These combinations of LZD and second-line anti-TB drugs were all active against MDR-TB with indifference or an additive effect, except LZD + capreomycin, which showed partial synergy.

Effect of fiber insertion depth on antibacterial efficacy of photodynamic therapy against Enterococcus faecalis in rootcanals.

This in vitro study evaluated the effect of fiber insertion depth on antimicrobial efficacy of antimicrobial photodynamic therapy (aPDT) using a photosensitizer (PS; toluidine blue) and a red light-emitting diode (LED) in root canals infected with Enterococcus faecalis. Single-rooted extracted teeth were prepared with nickel-titanium-instruments, sterilized, contaminated with E. faecalis, and incubated for 72h. Roots were randomly divided into four experimental groups: PS only, LED only, aPDT with LED in the apical third, aPDT with LED in the coronal third, as well as into infection and sterile controls (each n=10). Samples were taken by collecting standardized dentine shavings from the root canal walls. After serial dilution and culturing on blood agar, colony-forming units (CFU) were counted. Both aPDT groups showed a CFU reduction of 1-2 log10 steps compared with the infection control, whereas the effect of fiber insertion depth was negligible (<0.5 log10 steps). CFU reduction of approximately 0.5 log10 steps for PS alone was detected compared with the infection control, but PS alone was less effective than both aPDT groups. No antibacterial effect was detected for LED alone. aPDT reduced E. faecalis within the root canal, whereas fiber insertion depth had a negligible influence on antimicrobial effectiveness of aPDT. The insertion depth of the light-emitting diode may not influence the antibacterial efficacy of photodynamic therapy against E. faecalis in straight root canals.

Comparative Evaluation of the Antimicrobial Efficacy of Three Immersion Chemical Disinfectants on Clinically Derived Poly(Vinyl Siloxane) Impressions

To comparatively evaluate the antimicrobial efficacy of freshly prepared electrolyzed oxidizing water (EOW) with that of 2.4% glutaraldehyde (GA) and 1% sodium hypochlorite (SH) on clinically derived poly vinyl siloxane (PVS) impressions. Four clinically derived PVS impressions each were obtained from 10 subjects. One impression from each subject was randomly kept as control (group I), without disinfection. The remaining three impressions were randomly disinfected by immersion in either 2.4% GA (group II), 1% SH (group III), or freshly prepared EOW (group IV). The samples were subjected to microbial culture individually on brain heart infusion (BHI) agar medium. The organisms isolated were confirmed by visual examination and gram staining. Mean colony forming units (CFU) were counted, log10 reduction obtained and compared. Data were statistically analyzed using one-way ANOVA, followed by multiple comparisons using Tukey-HSD post hoc tests (p < 0.05). Streptococci, Staphylococci, Pseudomonas, Candida, Proteus, Klebsiella, and E. coli were isolated from all impressions including the controls, except those disinfected by EOW. All three disinfectants showed significant reduction in CFU and log10 reduction values as compared to the controls. EOW showed significantly higher reduction in log10 values compared to GA and SH, whereas GA and SH showed similar reductions. EOW, GA, and SH showed kill rates of 100%, 99.60%, and 99.82%, respectively. EOW showed significant antimicrobial efficacy as evidenced by reduction in log10 values when used as an immersion disinfectant for PVS impressions when compared with the results obtained using GA and SH. These results need further investigation. EOW shows high antimicrobial efficacy when used as an immersion disinfectant as compared to GA and SH for clinically derived PVS impressions.

Papel de los espermatozoides en la transmisión de bacterias uropatógenas: Escherichia coli y Enterococcus faecalis

IntroductionSperm travel through female reproductive tract seeking an oocyte to fertilise. During this journey, the sperm may interact with various substances and microorganisms that change its biology, interfering with reproductive success. The aim of this study was to evaluate the ability of human sperm to interact with and carry the bacteria Escherichia coli (E. coli) and Enterococcus faecalis (E. faecalis). Materials and methodsHuman sperm selected from semen samples of apparently healthy volunteers were incubated with increasing concentrations of E. coli and E. faecalis for one hour. Subsequently, quantitative cultures of the bacteria-sperm mixture were grown in MacConckey and chocolate agars with and without washing or post-infection treatment with trypsin. ResultsSperm interact and carry bacteria. Washes and trypsin treatment together cause a statistically significant reduction in colony-forming units for E. faecalis ATCC 29212, E. faecalis ATCC 51299 and E. coli ATCC 25922. ConclusionHuman sperm create strong interactions with E. coli and E. faecalis bacteria, promoting their dissemination in the female reproductive tract.

Antibacterial Efficacy of Several Surgical Hand Preparation Products Used by Veterinary Students.

To compare the antibacterial efficacy of different surgical hand antisepsis protocols used by veterinary students. Prospective, randomized, controlled study. Third year veterinary students (n=45). The participants were randomly assigned to 4 of the following 12 hand preparation product/time combinations: nonabrasive hand scrub method with 4% chlorhexidine gluconate (CH); hand rub with a mixture of 30% 1-propanol and 45% 2-propanol solution (MPS), 70% 2-propanol solution (IPS), or 61% ethanol solution with 1% chlorhexidine gluconate (ES/CH), with a contact time of 1.5, 3, or 5 minutes. Antibacterial efficacy was assessed after surgical hand preparation and at the end of surgery. Log reductions of total bacterial colony forming unit (CFU)/mL and positive aerobic culture rates were compared using multivariable analysis of variance and multivariable logistic regression, respectively. After surgical hand preparation, CH and ES/CH provided significantly higher log CFU reduction and lower positive culture rate for Gram-positive and spore-forming bacteria compared to MPS and IPS. Increase in contact time did not provide significant improvement in bacterial reduction. At the end of surgery, ES/CH provided significantly higher log CFU reduction compared to IPS and lower positive culture rate for Gram-positive bacteria compared to CH, MPS, and IPS. Increase in contact time significantly improved log CFU reduction in ES/CH and MPS groups. In our population of veterinary students ES/CH hand rubs or CH scrubs were more effective in reducing bacterial CFU during surgical hand preparation than MPS or IPS.

Comparison of antibacterial effect of photodynamic therapy using indocyanine green (Emundo) with 2% metronidazole and 2% chlorhexidine gel on Porphyromonas gingivalis (an in-vitro study)

BackgroundThe treatment of periodontal disease focuses on eradication or suppression of the pathogenic microbiota within the periodontal pocket. There are some mechanical and chemical ways, and recently antimicrobial photodynamic therapy to eliminate the bacteria.The aim of this in vitro study was to compare the effects of 2% chlorhexidine gel, 2% metronidazole in Orabase, antimicrobial photodynamic therapy with Emundo solution and Emundo solution on P. gingivalis. MethodsThe antibacterial activities of 2% CHX gel, 2% Metronidazole in Orabase, Emundo+Laser (an infra-red laser diode of 810nm, 300mW, continuous mode radiation, 30s and energy density of 11.5J/cm2), and Emundo against P. gingivalis was tested in vitro using two different methods; (1) Counting CFU/mL and (2) agar diffusion test (ADT). Data of CFU/mL were analyzed using one way ANOVA and Post hoc Tukey test (p<0.05). Data obtained from ADT test were analyzed using Kruskal-Wallis. ResultsThe percentage of colony-forming units reduction was (99.75, 99.98) in Metronidazole, (99.66, 99.85) in CHX, and (96.68, 96.68) in Laser+Emundo (96.68, 96.68) groups after 24 and 48h, respectively. The amount of bacterial reduction in terms of log10 CFU/mL was decreased in the Metronidazole, CHX, Laser+Emundo and, Emundo groups, respectively after 48h (p<0.05). The inhibition zone radius was decreased in CHX, Metronidazole and, Laser+Emundo, respectively (p<0.05). ConclusionsIt can be concluded that within the limitations of this in-vitro study, although photodynamic therapy with Emundo reduced the amount of P. gingivalis significantly, the use of metronidazole 2% in Orabase performed better in terms of reducing the amount of the bacteria. Also, the antibacterial effect of 2% CHX gel on P. gingivalis was significantly more than photodynamic therapy with Emundo.

Antibacterial ability of a novel Cu-bearing 2205 duplex stainless steel against Pseudomonas aeruginosa biofilm in artificial seawater

Marine microbiologically influenced corrosion (MMIC), initiated or promoted by biofilms of marine microorganisms, is becoming a leading cause of marine materials destruction, resulting in economic losses of billions of dollars each year. Copper ions released from the surface of an alloy can efficiently inhibit the attachment and the growth of some biofilm bacteria. The current study showed that the a novel copper-bearing 2205 duplex stainless steel (2205-Cu DSS) was effective against Pseudomonas aeruginosa in artificial seawater, achieving reductions of colony-forming units of 33.1%, 56.0% and 70.3% after incubation for 1, 3, and 5 days, respectively. More importantly, 2205-Cu DSS significantly decreased the thickness of the biofilm and induced cell death as compared to the 2205 DSS control. These results collectively suggest that 2205-Cu DSS may effectively mitigate the corrosive P. aeruginosa biofilm in applications as a potential anti-MMIC material in the marine environment.

Evaluation of a pulsed xenon ultraviolet light device for isolation room disinfection in a United Kingdom hospital

Pathogen transmission from contaminated surfaces can cause hospital-associated infections. Although pulsed xenon ultraviolet (PX-UV) light devices have been shown to decrease hospital room bioburden in the United States, their effectiveness in United Kingdom (UK) hospitals is less understood. Forty isolation rooms at the Queens Hospital (700 beds) in North London, UK, were sampled for aerobic bacteria after patient discharge, after manual cleaning with a hypochlorous acid-troclosene sodium solution, and after PX-UV disinfection. PX-UV device efficacy on known organisms was tested by exposing inoculated agar plates in a nonpatient care area. Turnaround times for device usage were recorded, and a survey of hospital staff for perceptions of the device was undertaken. After PX-UV disinfection, the bacterial contamination measured in colony forming units (CFU) decreased by 78.4%, a 91% reduction from initial bioburden levels prior to terminal cleaning. PX-UV exposure resulted in a 5-log CFU reduction for multidrug-resistant organisms (MDROs) on spiked plates. The average device turnaround time was 1 hour, with minimal impact on patient throughput. Ward staff were enthusiastic about device deployment, and device operators reported physical comfort in usage. PX-UV use decreased bioburden in patient discharge rooms and on agar plates spiked with MDROs. The implementation of the PX-UV device was well received by hospital cleaning and ward staff, with minimal disruption to patient flow.